Science.gov

Sample records for protection system actuation

  1. Flight control actuation system

    NASA Technical Reports Server (NTRS)

    Wingett, Paul T. (Inventor); Gaines, Louie T. (Inventor); Evans, Paul S. (Inventor); Kern, James I. (Inventor)

    2004-01-01

    A flight control actuation system comprises a controller, electromechanical actuator and a pneumatic actuator. During normal operation, only the electromechanical actuator is needed to operate a flight control surface. When the electromechanical actuator load level exceeds 40 amps positive, the controller activates the pneumatic actuator to offset electromechanical actuator loads to assist the manipulation of flight control surfaces. The assistance from the pneumatic load assist actuator enables the use of an electromechanical actuator that is smaller in size and mass, requires less power, needs less cooling processes, achieves high output forces and adapts to electrical current variations. The flight control actuation system is adapted for aircraft, spacecraft, missiles, and other flight vehicles, especially flight vehicles that are large in size and travel at high velocities.

  2. Flight control actuation system

    NASA Technical Reports Server (NTRS)

    Wingett, Paul T. (Inventor); Gaines, Louie T. (Inventor); Evans, Paul S. (Inventor); Kern, James I. (Inventor)

    2006-01-01

    A flight control actuation system comprises a controller, electromechanical actuator and a pneumatic actuator. During normal operation, only the electromechanical actuator is needed to operate a flight control surface. When the electromechanical actuator load level exceeds 40 amps positive, the controller activates the pneumatic actuator to offset electromechanical actuator loads to assist the manipulation of flight control surfaces. The assistance from the pneumatic load assist actuator enables the use of an electromechanical actuator that is smaller in size and mass, requires less power, needs less cooling processes, achieves high output forces and adapts to electrical current variations. The flight control actuation system is adapted for aircraft, spacecraft, missiles, and other flight vehicles, especially flight vehicles that are large in size and travel at high velocities.

  3. Firewater system inadvertent actuation frequencies

    SciTech Connect

    Schroeder, J.A.; Eide, S.A.

    1993-04-01

    This paper presents some recommended generic values for fire protection system inadvertent actuation frequencies. The frequencies are based on actual data from Department of Energy and commercial reactor plant facilities.

  4. Firewater system inadvertent actuation frequencies

    SciTech Connect

    Schroeder, J.A. ); Eide, S.A. )

    1993-01-01

    This paper presents some recommended generic values for fire protection system inadvertent actuation frequencies. The frequencies are based on actual data from Department of Energy and commercial reactor plant facilities.

  5. Tendon Driven Finger Actuation System

    NASA Technical Reports Server (NTRS)

    Ihrke, Chris A. (Inventor); Reich, David M. (Inventor); Bridgwater, Lyndon (Inventor); Linn, Douglas Martin (Inventor); Askew, Scott R. (Inventor); Diftler, Myron A. (Inventor); Platt, Robert (Inventor); Hargrave, Brian (Inventor); Valvo, Michael C. (Inventor); Abdallah, Muhammad E. (Inventor); Permenter, Frank Noble (Inventor); Mehling, Joshua S. (Inventor)

    2013-01-01

    A humanoid robot includes a robotic hand having at least one finger. An actuation system for the robotic finger includes an actuator assembly which is supported by the robot and is spaced apart from the finger. A tendon extends from the actuator assembly to the at least one finger and ends in a tendon terminator. The actuator assembly is operable to actuate the tendon to move the tendon terminator and, thus, the finger.

  6. Torsional Ratcheting Actuating System

    SciTech Connect

    BARNES,STEPHEN MATTHEW; MILLER,SAMUEL L.; RODGERS,M. STEVEN; BITSIE,FERNANDO

    2000-01-24

    A new type of surface micromachined ratcheting actuation system has been developed at the Microelectronics Development Laboratory at Sandia National Laboratories. The actuator uses a torsional electrostatic comb drive that is coupled to an external ring gear through a ratcheting scheme. The actuator can be operated with a single square wave, has minimal rubbing surfaces, maximizes comb finger density, and can be used for open-loop position control. The prototypes function as intended with a minimum demonstrated operating voltage of 18V. The equations of motion are developed for the torsional electrostatic comb drive. The resonant frequency, voltage vs. displacement and force delivery characteristics are predicted and compared with the fabricated device's performance.

  7. Enhancing the force capability of permanent magnet latching actuators for electromechanical valve actuation systems

    NASA Astrophysics Data System (ADS)

    Rens, J.; Clark, R. E.; Jewell, G. W.; Howe, D.

    2005-05-01

    This article introduces a topology of parallel-polarized permanent magnet latching actuator for use in electromagnetic valve actuation systems for internal combustion engines. The actuator has a number of advantages over reluctance actuators, commonly employed in such systems, in terms of reduced starting currents and fail-safe capability. The influence of a number of design features on actuator performance, such as tooth tapering, additional magnets to improve the main magnet flux path and prevent the onset of saturation, and mechanical clearances required to protect the permanent magnet from shock loads are investigated. The design study findings are verified by measurements on a prototype actuator.

  8. Solar actuated drain system

    SciTech Connect

    Sarver, G. E.; Worstell, B. W.

    1985-04-30

    A temperature actuated drain system is provided that comprises a siphon that has an inlet end for immersing in a pool of water to be drained from a roof surface and a discharge end communicating with a pressure-responsive one-way valve. A solar actuated enclosed chamber that contains a solar heat energy collector is located on the roof surface and is in open communication with the siphon by means of a tubular member that has its inlet end positioned closely adjacent the bottom of the interior of the chamber. The arrangement causes any appreciable amounts of water that accumulate within the chamber to be discharged from the chamber during the pumping action created by the heating and cooling of air within the chamber.

  9. Machine Protection System for the Stepper Motor Actuated SyLMAND Mirrors

    NASA Astrophysics Data System (ADS)

    Subramanian, V. R.; Achenbach, S.; Dolton, W.; Wells, G.; Hallin, E.; Klymyshyn, D. M.; Augustin, M.

    2010-06-01

    SyLMAND, the Synchrotron Laboratory for Micro and Nano Devices at the Canadian Light Source, consists of a dedicated X-ray lithography beamline on a bend magnet port, and process support laboratories in a clean room environment. The beamline includes a double mirror system with flat, chromium-coated silicon mirrors operated at varying grazing angles of incidence (4 mrad to 45 mrad) for spectral adjustment by high energy cut-off. Each mirror can be independently moved by two stepper motors to precisely control the pitch and vertical position. We present in this paper the machine protection system implemented in the double mirror system to allow for safe operation of the two mirrors and to avoid consequences of potential stepper motor malfunction.

  10. Machine Protection System for the Stepper Motor Actuated SyLMAND Mirrors

    SciTech Connect

    Subramanian, V. R.; Dolton, W.; Wells, G.; Hallin, E.; Achenbach, S.; Klymyshyn, D. M.; Augustin, M.

    2010-06-23

    SyLMAND, the Synchrotron Laboratory for Micro and Nano Devices at the Canadian Light Source, consists of a dedicated X-ray lithography beamline on a bend magnet port, and process support laboratories in a clean room environment. The beamline includes a double mirror system with flat, chromium-coated silicon mirrors operated at varying grazing angles of incidence (4 mrad to 45 mrad) for spectral adjustment by high energy cut-off. Each mirror can be independently moved by two stepper motors to precisely control the pitch and vertical position. We present in this paper the machine protection system implemented in the double mirror system to allow for safe operation of the two mirrors and to avoid consequences of potential stepper motor malfunction.

  11. Self-actuating reactor shutdown system

    DOEpatents

    Barrus, Donald M.; Brummond, Willian A; Peterson, Leslie F.

    1988-01-01

    A control system for the automatic or self-actuated shutdown or "scram" of a nuclear reactor. The system is capable of initiating scram insertion by a signal from the plant protection system or by independent action directly sensing reactor conditions of low-flow or over-power. Self-actuation due to a loss of reactor coolant flow results from a decrease of pressure differential between the upper and lower ends of an absorber element. When the force due to this differential falls below the weight of the element, the element will fall by gravitational force to scram the reactor. Self-actuation due to high neutron flux is accomplished via a valve controlled by an electromagnet and a thermionic diode. In a reactor over-power, the diode will be heated to a change of state causing the electromagnet to be shorted thereby actuating the valve which provides the changed flow and pressure conditions required for scramming the absorber element.

  12. Hybrid electromechanical actuator and actuation system

    NASA Technical Reports Server (NTRS)

    Su, Ji (Inventor); Xu, Tian-Bing (Inventor)

    2008-01-01

    A hybrid electromechanical actuator has two different types of electromechanical elements, one that expands in a transverse direction when electric power is applied thereto and one that contracts in a transverse direction when electric power is applied thereto. The two electromechanical elements are (i) disposed in relation to one another such that the transverse directions thereof are parallel to one another, and (ii) mechanically coupled to one another at least at two opposing edges thereof. Electric power is applied simultaneously to the elements.

  13. Electromechanical propellant control system actuator

    NASA Technical Reports Server (NTRS)

    Myers, W. Neill; Weir, Rae Ann

    1990-01-01

    New control mechanism technologies are currently being sought to provide alternatives to hydraulic actuation systems. The Propulsion Laboratory at Marshall Space Flight Center (MSFC) is involved in the development of electromechanical actuators (EMA's) for this purpose. Through this effort, an in-house designed electromechanical propellant valve actuator has been assembled and is presently being evaluated. This evaluation will allow performance comparisons between EMA and hydraulics systems. The in-house design consists of the following hardware: a three-phase brushless motor, a harmonic drive, and an output spline which will mate with current Space Shuttle Main Engine (SSME) propellant control valves. A resolver and associated electronics supply position feedback for the EMA. System control is provided by a solid-state electronic controller and power supply. Frequency response testing has been performed with further testing planned as hardware and test facilities become available.

  14. NASA pyrotechnically actuated systems program

    NASA Technical Reports Server (NTRS)

    Schulze, Norman R.

    1993-01-01

    The Office of Safety and Mission Quality initiated a Pyrotechnically Actuated Systems (PAS) Program in FY-92 to address problems experienced with pyrotechnically actuated systems and devices used both on the ground and in flight. The PAS Program will provide the technical basis for NASA's projects to incorporate new technological developments in operational systems. The program will accomplish that objective by developing/testing current and new hardware designs for flight applications and by providing a pyrotechnic data base. This marks the first applied pyrotechnic technology program funded by NASA to address pyrotechnic issues. The PAS Program has been structured to address the results of a survey of pyrotechnic device and system problems with the goal of alleviating or minimizing their risks. Major program initiatives include the development of a Laser Initiated Ordnance System, a pyrotechnic systems data base, NASA Standard Initiator model, a NASA Standard Linear Separation System and a NASA Standard Gas Generator. The PAS Program sponsors annual aerospace pyrotechnic systems workshops.

  15. Biomaterial systems for mechanosensing and actuation.

    PubMed

    Fratzl, Peter; Barth, Friedrich G

    2009-11-26

    Living organisms use composite materials for various functions, such as mechanical support, protection, motility and the sensing of signals. Although the individual components of these materials may have poor mechanical qualities, they form composites of polymers and minerals with a remarkable variety of functional properties. Researchers are now using these natural systems as models for artificial mechanosensors and actuators, through studying both natural structures and their interactions with the environment. In addition to inspiring the design of new materials, analysis of natural structures on this basis can provide insight into evolutionary constraints on structure-function relationships in living organisms and the variety of structural solutions that emerged from these constraints. PMID:19940914

  16. 30 CFR 75.1103-6 - Automatic fire sensors; actuation of fire suppression systems.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Automatic fire sensors; actuation of fire... Protection § 75.1103-6 Automatic fire sensors; actuation of fire suppression systems. Point-type heat sensors or automatic fire sensor and warning device systems may be used to actuate deluge-type water...

  17. 30 CFR 75.1103-6 - Automatic fire sensors; actuation of fire suppression systems.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Automatic fire sensors; actuation of fire... Protection § 75.1103-6 Automatic fire sensors; actuation of fire suppression systems. Point-type heat sensors or automatic fire sensor and warning device systems may be used to actuate deluge-type water...

  18. 30 CFR 75.1103-6 - Automatic fire sensors; actuation of fire suppression systems.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Automatic fire sensors; actuation of fire... Protection § 75.1103-6 Automatic fire sensors; actuation of fire suppression systems. Point-type heat sensors or automatic fire sensor and warning device systems may be used to actuate deluge-type water...

  19. 30 CFR 75.1103-6 - Automatic fire sensors; actuation of fire suppression systems.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Automatic fire sensors; actuation of fire... Protection § 75.1103-6 Automatic fire sensors; actuation of fire suppression systems. Point-type heat sensors or automatic fire sensor and warning device systems may be used to actuate deluge-type water...

  20. 30 CFR 75.1103-6 - Automatic fire sensors; actuation of fire suppression systems.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Automatic fire sensors; actuation of fire... Protection § 75.1103-6 Automatic fire sensors; actuation of fire suppression systems. Point-type heat sensors or automatic fire sensor and warning device systems may be used to actuate deluge-type water...

  1. Digital flight control actuation system study

    NASA Technical Reports Server (NTRS)

    Rossing, R.; Hupp, R.

    1974-01-01

    Flight control actuators and feedback sensors suitable for use in a redundant digital flight control system were examined. The most appropriate design approach for an advanced digital flight control actuation system for development and use in a fly-by-wire system was selected. The concept which was selected consisted of a PM torque motor direct drive. The selected system is compatible with concurrent and independent development efforts on the computer system and the control law mechanizations.

  2. Conducting IPN actuators for biomimetic vision system

    NASA Astrophysics Data System (ADS)

    Festin, Nicolas; Plesse, Cedric; Chevrot, Claude; Teyssié, Dominique; Pirim, Patrick; Vidal, Frederic

    2011-04-01

    In recent years, many studies on electroactive polymer (EAP) actuators have been reported. One promising technology is the elaboration of electronic conducting polymers based actuators with Interpenetrating Polymer Networks (IPNs) architecture. Their many advantageous properties as low working voltage, light weight and high lifetime (several million cycles) make them very attractive for various applications including robotics. Our laboratory recently synthesized new conducting IPN actuators based on high molecular Nitrile Butadiene Rubber, poly(ethylene oxide) derivative and poly(3,4-ethylenedioxithiophene). The presence of the elastomer greatly improves the actuator performances such as mechanical resistance and output force. In this article we present the IPN and actuator synthesis, characterizations and design allowing their integration in a biomimetic vision system.

  3. Actuator for automatic cruising system

    SciTech Connect

    Suzuki, K.

    1989-03-07

    An actuator for an automatic cruising system is described, comprising: a casing; a control shaft provided in the casing for rotational movement; a control motor for driving the control shaft; an input shaft; an electromagnetic clutch and a reduction gear which are provided between the control motor and the control shaft; and an external linkage mechanism operatively connected to the control shaft; wherein the reduction gear is a type of Ferguson's mechanical paradox gear having a pinion mounted on the input shaft always connected to the control motor; a planetary gear meshing with the pinion so as to revolve around the pinion; a static internal gear meshing with the planetary gear and connected with the electromagnetic clutch for movement to a position restricting rotation of the static internal gear; and a rotary internal gear fixed on the control shaft and meshed with the planetary gear, the rotary internal gear having a number of teeth slightly different from a number of teeth of the static internal gear; and the electromagnetic clutch has a tubular electromagnetic coil coaxially provided around the input shaft and an engaging means for engaging and disengaging with the static internal gear in accordance with on-off operation of the electromagnetic coil.

  4. Hydraulic Actuator System for Rotor Control

    NASA Technical Reports Server (NTRS)

    Ulbrich, Heinz; Althaus, Josef

    1991-01-01

    In the last ten years, several different types of actuators were developed and fabricated for active control of rotors. A special hydraulic actuator system capable of generating high forces to rotating shafts via conventional bearings is addressed. The actively controlled hydraulic force actuator features an electrohydraulic servo valve which can produce amplitudes and forces at high frequencies necessary for influencing rotor vibrations. The mathematical description will be given in detail. The experimental results verify the theoretical model. Simulations already indicate the usefulness of this compact device for application to a real rotor system.

  5. Electrostatic Discharge (ESD) Protection for a Laser Diode Ignited Actuator

    SciTech Connect

    SALAS, FREDERICK J.; SANCHEZ, DANIEL H.; WEINLEIN, JOHN HARVEY

    2003-06-01

    The use of laser diodes in devices to ignite pyrotechnics provides unique new capabilities including the elimination of electrostatic discharge (ESD) pulses entering the device. The Faraday cage formed by the construction of these devices removes the concern of inadvertent ignition of the energetic material. However, the laser diode itself can be damaged by ESD pulses, therefore, to enhance reliability, some protection of the laser diode is necessary. The development of the MC4612 Optical Actuator has included a circuit to protect the laser diode from ESD pulses including the ''Fisher'' severe human body ESD model. The MC4612 uses a laser diode and is designed to replace existing hot-wire actuators. Optical energy from a laser diode, instead of electrical energy, is used to ignite the pyrotechnic. The protection circuit is described along with a discussion of how the circuit design addresses and circumvents the historic 1Amp/1Watt requirement that has been applicable to hot-wire devices.

  6. Microelectromechanical Systems Actuator Based Reconfigurable Printed Antenna

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N. (Inventor)

    2005-01-01

    A polarization reconfigurable patch antenna is disclosed. The antenna includes a feed element, a patch antenna element electrically connected to the feed element, and at least one microelectromechanical systems (MEMS) actuator, with a partial connection to the patch antenna element along an edge of the patch antenna element. The polarization of the antenna can be switched between circular polarization and linear polarization through action of the at least one MEMS actuator.

  7. Propeller pitch change actuation system

    SciTech Connect

    Kusiak, E.H.

    1988-06-28

    An apparatus is described for adjusting the pitch of a variable pitch propeller blade characterized by: an actuator for setting the pitch of the propeller blade the actuator having; a rotatable screw for setting propeller pitch, a nut mounted for longitudinal motion along the screw as the screw is rotated, means for connecting the nut to the propeller blade to adjust the pitch of the propeller blade as the screw rotates, and a rotatable means mounted within the nut for locking the nut against longitudinal motion if the rotatable means is not rotating with the longitudinal motion of the nut and for allowing the nut to move longitudinally if the rotatable means is rotating with the longitudinal motion of the nut.

  8. Dielectric Elastomer Actuated Systems and Methods

    NASA Technical Reports Server (NTRS)

    Dubowsky, Steven (Inventor); Hafez, Moustapha (Inventor); Lichter, Matthew (Inventor); Weiss, Peter (Inventor); Wingert, Andreas (Inventor)

    2008-01-01

    The system of the present invention includes an actuator having at least two electrodes, an elastomeric dielectric film disposed between the two electrodes, and a frame attached to the elastomeric dielectric film. The frame provides a linear actuation force characteristic over a displacement range. The displacement range is preferably the stroke of the actuator. The displacement range can be about 5 mm and greater. Further, the frame can include a plurality of configurations, for example, at least a rigid members coupled to a flexible member wherein the frame provides an elastic restoring force. In preferred embodiments, the rigid member can be, but is not limited to, curved beams, parallel beams, rods and plates. In a preferred embodiment the actuator can further include a passive element disposed between two flexible members such as, for example, links to tune a stiffness characteristic of the actuator. The passive element can be a bi-stable element. Further, the actuator can include a plurality of layers of the elastomeric dielectric film integrated into the frame. The elastomeric film can be made of different materials such as, for example, acrylic, silicone and latex.

  9. Electrostatic actuators for portable microfluidic systems

    NASA Astrophysics Data System (ADS)

    Tice, Joshua

    Both developed and developing nations have an urgent need to diagnose disease cheaply, reliably, and independently of centralized facilities. Microfulidic platforms are well-positioned to address the need for portable diagnostics, mainly due to their obvious advantage in size. However, most microfluidic methods rely on equipment outside of the chip either for driving fluid flow (e.g., syringe pumps) or for taking measurements (e.g., lasers or microscopes). The energy and space requirements of the whole system inhibit portability and contribute to costs. To capitalize on the strengths of microfluidic platforms and address the serious needs of society, system components need to be miniaturized. Also, miniaturization should be accomplished as simply as possible, considering that simplicity is usually requisite for achieving truly transformative technology. Herein, I attempt to address the issue of controlling fluid flow in portable microfluidic systems. I focus on systems that are driven by elastomer-based membrane valves, since these valves are inherently simple, yet they are capable of sophisticated fluid manipulation. Others have attempted to modify pneumatic microvalves for portable applications, e.g., by transitioning to electromagnetic, thermopneumatic, or piezoelectric actuation principles. However, none of these strategies maintain the proper balance of simplicity, functionality, and ease of integration. My research centers on electrostatic actuators, due to their conceptual simplicity and the efficacy of electrostatic forces on the microscale. To ensure easy integration with polymer-based systems, and to maintain simplicity in the fabrication procedure, the actuators were constructed solely from poly(dimethylsiloxane) and multi-walled carbon nanotubes. In addition, the actuators were fabricated exclusively with soft-lithographic techniques. A mathematical model was developed to identify actuator parameters compatible with soft-lithography, and also to

  10. Remote actuation system speeds deepwater well completions

    SciTech Connect

    Bussear, T.

    1996-10-07

    Substantial savings in rig time, operating expenses, and overall completion costs, particularly in extended-reach and deepwater wells, can be realized with advanced wireless communication techniques and electronically enhanced pulse-actuation systems for completing wells. With drilling and completion costs climbing steadily, especially offshore, operators need to minimize rig time without sacrificing reliability, safety, or ultimate well productivity. During the past several months, Baker Oil Tools` EDGE remote actuation system, a surface-controlled communications system that relies on pressure-wave pulses to actuate electronics-equipped downhole completion tools, has been deployed commercially in a number of deep, high-pressure, high-temperature wells in the Gulf of Mexico. The paper discusses the system basics, the Mars installation, benefits and limitations, a simulator that was developed, time improvements, tangible savings, and further tools being manufactured for other jobs.

  11. Accommodating Actuator Failures in Flight Control Systems

    NASA Technical Reports Server (NTRS)

    Hess, R. A.; Siwakosit, W.; Chung, J.

    1998-01-01

    A technique for the design of flight control systems that can accommodate a set of actuator failures is presented. As employed herein, an actuator failure is defined as any change in the parametric model of the actuator which can adversely affect actuator performance. The technique is based upon the formulation of a fixed feedback topology which ensures at least stability in the presence of the failures in the set. The fixed compensation is obtained from a loop-shaping design procedure similar to Quantitative Feedback Theory and provides stability robustness in the presence of uncertainty in the vehicle dynamics caused by the failures. System adaptation to improve performance after actuator failure(s) occurs through a static gain adjustment in the compensator followed by modification of the system prefilter. Precise identification of the vehicle dynamics is unnecessary. Application to a single-input, single-output design using a simplified model of the longitudinal dynamics of the NASA High Angle of Attack Research Vehicle is discussed. Non-real time simulations of the system including a model of the pilot demonstrate the effectiveness and limitations of the approach.

  12. Choosing Actuators for Automatic Control Systems of Thermal Power Plants

    SciTech Connect

    Gorbunov, A. I.; Serdyukov, O. V.

    2015-03-15

    Two types of actuators for automatic control systems of thermal power plants are analyzed: (i) pulse-controlled actuator and (ii) analog-controlled actuator with positioning function. The actuators are compared in terms of control circuit, control accuracy, reliability, and cost.

  13. A wireless actuating drug delivery system

    NASA Astrophysics Data System (ADS)

    Jo, Won-Jun; Baek, Seung-Ki; Park, Jung-Hwan

    2015-04-01

    A wireless actuating drug delivery system was devised. The system is based on induction heating for drug delivery. In this study, thermally generated nitrogen gas produced by induction heating of azobisisobutyronitrile (AIBN) was utilized for pressure-driven release of the drug. The delivery device consists of an actuator chamber, a drug reservoir, and a microchannel. A semicircular copper disc (5 and 6 mm in diameter and 100 µm thick), and thermal conductive tape were integrated as the heating element in the actuator chamber. The final device was 2.7 mm thick. 28 µl of drug solution were placed in the reservoir and the device released the drug quickly at the rate of 6 µl s-1 by induction heating at 160 µT of magnetic intensity. The entire drug solution was released and dispersed after subcutaneous implantation under identical experimental condition. This study demonstrates that the device was simply prepared and drug delivery could be achieved by wireless actuation of a thin, pressure-driven actuator.

  14. Pressure-actuated joint system

    NASA Technical Reports Server (NTRS)

    McGuire, John R. (Inventor)

    2004-01-01

    A pressure vessel is provided that includes first and second case segments mated with one another. First and second annular rubber layers are disposed inboard of the first and second case segments, respectively. The second annular rubber layer has a slot extending from the radial inner surface across a portion of its thickness to define a main body portion and a flexible portion. The flexible portion has an interfacing surface portion abutting against an interfacing surface portion of the first annular rubber layer to follow movement of the first annular rubber layer during operation of the pressure vessel. The slot receives pressurized gas and establishes a pressure-actuated joint between the interfacing surface portions. At least one of the interfacing surface portions has a plurality of enclosed and sealed recesses formed therein.

  15. New, electronically enhanced remote actuation system

    SciTech Connect

    1997-04-01

    Conventional completion techniques are time intensive, require tubing manipulation and multiple well interventions, which make them less than desirable for extended-reach and deepwater applications. The ideal setting method for extended-reach and deepwater applications requires a one-trip system where the packer is run in on the completion string, actuated, and set without any tubing manipulation or well intervention. No single conventional setting method meets these requirements. Electronically enhanced remote actuation allows for reduction, and in some cases total elimination, of common well-intervention operations. A new, mud-pulse-frequency-based communication technique that actuates and manipulates downhole tools equipped with onboard electronics has been developed. The downhole tools are programmed at the surface to recognize 1 of 16 discrete actuation commands from a computer-controlled, portable terminal unit. Once in position, the tools are actuated on receipt of a specific command sent from the portable terminal unit. As many as 16 devices can be activated independently of one another in a single wellbore. Pulse-communication technology can be adapted to many types of downhole completion devices, including packers, sliding sleeves, and temporary plugs.

  16. Microelectromechanical Systems (MEMS) Actuators for Antenna Reconfigurability

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.; Chun, Donghoon; Katehi, Linda P. B.

    2001-01-01

    A novel microelectromechanical systems (MEMS) actuator for patch antenna reconfiguration, is presented for the first time. A key feature is the capability of multi-band operation without greatly increasing the antenna element dimensions. Experimental results demonstrate that the center frequency can be reconfigured from few hundred MHz to few GHz away from the nominal operating frequency.

  17. 14 CFR 33.72 - Hydraulic actuating systems.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Hydraulic actuating systems. 33.72 Section... AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.72 Hydraulic actuating systems. Each hydraulic actuating system must function properly under all conditions in which...

  18. Sequential growth and monitoring of a polypyrrole actuator system

    NASA Astrophysics Data System (ADS)

    Sarrazin, J. C.; Mascaro, Stephen A.

    2014-03-01

    Electroactive polymers (EAPs) have emerged as viable materials in sensing and actuating applications, but the capability to mimic the structure and function of natural muscle is increased due to their ability to permit additional, sequential synthesis steps between stages of actuation. Current work is improving upon the mechanical performance in terms of achievable stresses, strains, and strain rates, but issues still remain with actuator lifetime and adaptability. This work seeks to create a bioinspired polymer actuation system that can be monitored using state estimation and adjusted in vivo during operation. The novel, time-saving process of sequential growth was applied to polymer actuator systems for the initial growth, as well as additional growth steps after actuation cycles. Synthesis of conducting polymers on a helical metal electrode directs polymer shape change during actuation, assists in charge distribution along the polymer for actuation, and as is described in this work, constructs a constant working electrode/polymer connection during operation which allows sequential polymer growth based on a performance need. The polymer system is monitored by means of a reduced-order, state estimation model that works between growth and actuation cycles. In this case, actuator stress is improved between growth cycles. The ability for additional synthesis of the polymer actuator not only creates an actuator system that can be optimized based on demand, but creates a dynamic actuator system that more closely mimics natural muscle capability.

  19. Nonlinear identification of ionic polymer actuator systems

    NASA Astrophysics Data System (ADS)

    Kothera, Curt S.; Lacy, Seth L.; Erwin, R. Scott; Leo, Donald J.

    2004-07-01

    Ionic polymers are a class of electromechanically coupled materials that can be used as flexible transducers. When set up in the cantilever configuration, the actuators exhibit a large bending deflection when an electric field is applied across their thickness. Being a relatively new research topic, the governing physical and chemical mechanisms are not yet fully understood. Experimental results have demonstrated nonlinear dynamic behavior. The nonlinear dynamics can be seen in the response of current, displacement, and velocity of the actuator. This work presents results for the nonlinear identification of ionic polymer actuator systems driven at a specific frequency. Identification results using a 5th-degree Volterra expansion show that the nonlinear distortion can be accurately modeled. Using such a high power in the series expansion is necessary to capture the most dominant harmonics, as evidenced when examining the power spectral density of the response. An investigation of how nonlinearities enter into the response is also performed. By analyzing both the actuation current and tip velocity, results show that both the voltage to current and current to velocity stages influence the nonlinear response, but the voltage to current stage is more dominantly nonlinear.

  20. NASA aerospace pyrotechnically actuated systems: Program plan

    NASA Technical Reports Server (NTRS)

    Schulze, Norman R.

    1992-01-01

    The NASA Aerospace Pyrotechnically Actuated Systems (PAS) Program, a focused technology program, is being initiated to enhance the reliability, safety, and performance of pyrotechnically actuated systems. In broad terms, this Program Plan presents the approach that helps to resolve concerns raised by the NASA/DOD/DOE Aerospace Pyrotechnic Steering Committee. This Plan reflects key efforts needed in PAS technology. The resources committed to implement the Program will be identified in the Program Implementation Plan (PIP). A top level schedule is included along with major Program milestones and products. Responsibilities are defined in the PIP. The Plan identifies the goals and detailed objectives which define how those goals are to be accomplished. The Program will improve NASA's capabilities to design, develop, manufacture, and test pyrotechnically actuated systems for NASA's programs. Program benefits include the following: advanced pyrotechnic systems technology developed for NASA programs; hands-on pyrotechnic systems expertise; quick response capability to investigate and resolve pyrotechnic problems; enhanced communications and intercenter support among the technical staff; and government-industry PAS technical interchange. The PAS Program produces useful products that are of a broad-based technology nature rather than activities intended to meet specific technology objectives for individual programs. Serious problems have occurred with pyrotechnic devices although near perfect performance is demanded by users. The lack of a program to address those problems in the past is considered a serious omission. The nature of problems experienced as revealed by a survey are discussed and the origin of the program is explained.

  1. Valve system incorporating single failure protection logic

    DOEpatents

    Ryan, Rodger; Timmerman, Walter J. H.

    1980-01-01

    A valve system incorporating single failure protective logic. The system consists of a valve combination or composite valve which allows actuation or de-actuation of a device such as a hydraulic cylinder or other mechanism, integral with or separate from the valve assembly, by means of three independent input signals combined in a function commonly known as two-out-of-three logic. Using the input signals as independent and redundant actuation/de-actuation signals, a single signal failure, or failure of the corresponding valve or valve set, will neither prevent the desired action, nor cause the undesired action of the mechanism.

  2. Actuator development for the Instrument Pointing System (IPS)

    NASA Technical Reports Server (NTRS)

    Suttner, K.

    1984-01-01

    The mechanisms of the instrument pointing system (IPS) are described. Particular emphasis is placed on the actuators which are necessary for operating the IPS. The actuators are described as follows: (1) two linear actuators that clamp the gimbals down during ascent and descent; (2) two linear actuators that attach the payload to the IPS during the mission, and release it into the payload clamps; (3) one rotational actuator that opens and closes the payload clamps; and (4) three identical drive units that represent the three orthogonal gimbal axes and are the prime movers for pointing. Design features, manufacturing problems, test performance, and results are presented.

  3. Microelectromechanical systems integrating molecular spin crossover actuators

    NASA Astrophysics Data System (ADS)

    Manrique-Juarez, Maria D.; Rat, Sylvain; Mathieu, Fabrice; Saya, Daisuke; Séguy, Isabelle; Leïchlé, Thierry; Nicu, Liviu; Salmon, Lionel; Molnár, Gábor; Bousseksou, Azzedine

    2016-08-01

    Silicon MEMS cantilevers coated with a 200 nm thin layer of the molecular spin crossover complex [Fe(H2B(pz)2)2(phen)] (H2B(pz)2 = dihydrobis(pyrazolyl)borate and phen = 1,10-phenantroline) were actuated using an external magnetic field and their resonance frequency was tracked by means of integrated piezoresistive detection. The light-induced spin-state switching of the molecules from the ground low spin to the metastable high spin state at 10 K led to a well-reproducible shift of the cantilever's resonance frequency (Δfr = -0.52 Hz). Control experiments at different temperatures using coated as well as uncoated devices along with simple calculations support the assignment of this effect to the spin transition. This latter translates into changes in mechanical behavior of the cantilever due to the strong spin-state/lattice coupling. A guideline for the optimization of device parameters is proposed so as to efficiently harness molecular scale movements for large-scale mechanical work, thus paving the road for nanoelectromechanical systems (NEMS) actuators based on molecular materials.

  4. Intelligent redundant actuation system requirements and preliminary system design

    NASA Technical Reports Server (NTRS)

    Defeo, P.; Geiger, L. J.; Harris, J.

    1985-01-01

    Several redundant actuation system configurations were designed and demonstrated to satisfy the stringent operational requirements of advanced flight control systems. However, this has been accomplished largely through brute force hardware redundancy, resulting in significantly increased computational requirements on the flight control computers which perform the failure analysis and reconfiguration management. Modern technology now provides powerful, low-cost microprocessors which are effective in performing failure isolation and configuration management at the local actuator level. One such concept, called an Intelligent Redundant Actuation System (IRAS), significantly reduces the flight control computer requirements and performs the local tasks more comprehensively than previously feasible. The requirements and preliminary design of an experimental laboratory system capable of demonstrating the concept and sufficiently flexible to explore a variety of configurations are discussed.

  5. Design and performances of JPCam actuator system

    NASA Astrophysics Data System (ADS)

    Casalta, Joan Manel; Canchado, Manuel; Molins, Albert; Redondo, Miguel; Tomàs, Albert; Catalan, Albert

    2014-07-01

    JPCam is designed to perform the Javalambre-PAU Astrophysical Survey (J-PAS), a photometric survey of the northern sky with the new JST telescope being constructed in the Observatorio Astrofísico of Javalambre in Spain by CEFCA (Centro de Estudios de Física del Cosmos de Aragón). SENER has been responsible for the design, manufacturing, verification and delivery of the JPCam Actuator System that will be installed between the Telescope and the cryogenic Camera Subsystem. The main function is to control the instrument position to guarantee the image quality required during observations in all field of view and compensate deformations produced by gravity and temperature changes. The paper summarizes the main aspects of the hexapod design and earliest information related of integration and performances tests results.

  6. Flywheel energy storage for electromechanical actuation systems

    NASA Technical Reports Server (NTRS)

    Hockney, Richard L.; Goldie, James H.; Kirtley, James L.

    1991-01-01

    The authors describe a flywheel energy storage system designed specifically to provide load-leveling for a thrust vector control (TVC) system using electromechanical actuators (EMAs). One of the major advantages of an EMA system over a hydraulic system is the significant reduction in total energy consumed during the launch profile. Realization of this energy reduction will, however, require localized energy storage capable of delivering the peak power required by the EMAs. A combined flywheel-motor/generator unit which interfaces directly to the 20-kHz power bus represents an ideal candidate for this load leveling. The overall objective is the definition of a flywheel energy storage system for this application. The authors discuss progress on four technical objectives: (1) definition of the specifications for the flywheel-motor/generator system, including system-level trade-off analysis; (2) design of the flywheel rotor; (3) design of the motor/generator; and (4) determination of the configuration for the power management system.

  7. MOSFET Switching Circuit Protects Shape Memory Alloy Actuators

    NASA Technical Reports Server (NTRS)

    Gummin, Mark A.

    2011-01-01

    A small-footprint, full surface-mount-component printed circuit board employs MOSFET (metal-oxide-semiconductor field-effect transistor) power switches to switch high currents from any input power supply from 3 to 30 V. High-force shape memory alloy (SMA) actuators generally require high current (up to 9 A at 28 V) to actuate. SMA wires (the driving element of the actuators) can be quickly overheated if power is not removed at the end of stroke, which can damage the wires. The new analog driver prevents overheating of the SMA wires in an actuator by momentarily removing power when the end limit switch is closed, thereby allowing complex control schemes to be adopted without concern for overheating. Either an integral pushbutton or microprocessor-controlled gate or control line inputs switch current to the actuator until the end switch line goes from logic high to logic low state. Power is then momentarily removed (switched off by the MOSFET). The analog driver is suited to use with nearly any SMA actuator.

  8. Ultrathin Alvarez lens system actuated by artificial muscles.

    PubMed

    Petsch, S; Grewe, A; Köbele, L; Sinzinger, S; Zappe, H

    2016-04-01

    A key feature of Alvarez lenses is that they may be tuned in focal length using lateral rather than axial translation, thus reducing the overall length of a focus-tunable optical system. Nevertheless the bulk of classical microsystems actuators limits further miniaturization. We present here a new, ultrathin focus-tunable Alvarez lens fabricated using molding techniques and actuated using liquid crystal elastomer (LCE) artificial muscle actuators. The large deformation generated by the LCE actuators permits the integration of the actuators in-plane with the mechanical and optical system and thus reduces the device thickness to only 1.6 mm. Movement of the Alvarez lens pair of 178 μm results in a focal length change of 3.3 mm, based on an initial focal length of 28.4 mm. This design is of considerable interest for realization of ultraflat focus-tunable and zoom systems. PMID:27139677

  9. Adaptive control of nonlinear systems with actuator failures and uncertainties

    NASA Astrophysics Data System (ADS)

    Tang, Xidong

    2005-11-01

    Actuator failures have damaging effect on the performance of control systems, leading to undesired system behavior or even instability. Actuator failures are unknown in terms of failure time instants, failure patterns, and failure parameters. For system safety and reliability, the compensation of actuator failures is of both theoretical and practical significance. This dissertation is to further the study of adaptive designs for actuator failure compensation to nonlinear systems. In this dissertation a theoretical framework for adaptive control of nonlinear systems with actuator failures and system uncertainties is established. The contributions are the development of new adaptive nonlinear control schemes to handle unknown actuator failures for convergent tracking performance, the specification of conditions as a guideline for applications and system designs, and the extension of the adaptive nonlinear control theory. In the dissertation, adaptive actuator failure compensation is studied for several classes of nonlinear systems. In particular, adaptive state feedback schemes are developed for feedback linearizable systems and parametric strict-feedback systems. Adaptive output feedback schemes are deigned for output-feedback systems and a class of systems with unknown state-dependent nonlinearities. Furthermore, adaptive designs are addressed for MIMO systems with actuator failures, based on two grouping techniques: fixed grouping and virtual grouping. Theoretical issues such as controller structures, actuation schemes, zero dynamics, observation, grouping conditions, closed-loop stability, and tracking performance are extensively investigated. For each scheme, design conditions are clarified, and detailed stability and performance analysis is presented. A variety of applications including a wing-rock model, twin otter aircraft, hypersonic aircraft, and cooperative multiple manipulators are addressed with simulation results showing the effectiveness of the

  10. Thermionic switched self-actuating reactor shutdown system

    DOEpatents

    Barrus, Donald M.; Shires, Charles D.; Brummond, William A.

    1989-01-01

    A self-actuating reactor shutdown system incorporating a thermionic switched electromagnetic latch arrangement which is responsive to reactor neutron flux changes and to reactor coolant temperature changes. The system is self-actuating in that the sensing thermionic device acts directly to release (scram) the control rod (absorber) without reference or signal from the main reactor plant protective and control systems. To be responsive to both temperature and neutron flux effects, two detectors are used, one responsive to reactor coolant temperatures, and the other responsive to reactor neutron flux increase. The detectors are incorporated into a thermionic diode connected electrically with an electromagnetic mechanism which under normal reactor operating conditions holds the the control rod in its ready position (exterior of the reactor core). Upon reaching either a specified temperature or neutron flux, the thermionic diode functions to short-circuit the electromagnetic mechanism causing same to lose its holding power and release the control rod, which drops into the reactor core region under gravitational force.

  11. Liquid rocket actuators and operators. [in spacecraft control systems

    NASA Technical Reports Server (NTRS)

    1973-01-01

    All the types of actuators and associated operators used in booster, upper stage, and spacecraft propulsion and reaction-control systems except for chemical-explosive actuators and turbine actuators are discussed. Discussion of static and dynamic seals, mechanical transmission of motion, and instrumentation is included to the extent that actuator or operator design is affected. Selection of the optimum actuator configuration is discussed for specific application which require a tradeoff study that considers all the relevant factors: available energy sources, load capacity, stroke, speed of response, leakage limitations, environmental conditions, chemical compatibility, storage life and conditions, size, weight, and cost. These factors are interrelated with overall control-system design evaluations that are beyond the scope of this monograph; however, literature references are cited for a detailed review of the general considerations. Perinent advanced-state-of-the-art design concepts are surveyed briefly.

  12. The monoselector: a new actuator for an environmental control system.

    PubMed

    Leliveld, W H

    1989-01-01

    Within the Division of Medical Electrical Engineering of the Eindhoven University of Technology, a portable microprocessor-controlled actuator for an environmental control system has been developed. It allows severely physically disabled persons to remotely control up to 16 different electrical appliances using only a single switch. The actuator, the 'Monoselector', actuates the Busch Timac X-10 remote control system. The complete system is very easy to install, transportable, flexible, easy to use and has extensive control possibilities. Since its introduction at the Hannover Trade Fair in 1987 the Monoselector has been commercially available. PMID:2733013

  13. Cavity optoelectromechanical system combining strong electrical actuation with ultrasensitive transduction

    SciTech Connect

    McRae, Terry G.; Lee, Kwan H.; Harris, Glen I.; Knittel, Joachim; Bowen, Warwick P.

    2010-08-15

    A cavity optoelectromechanical system is reported which combines the ultrasensitive transduction of cavity optomechanical systems with the electrical actuation of nanoelectromechanical systems. Ultrasensitive mechanical transduction is achieved via optomechanical coupling. Electrical gradient forces as large as 0.40 {mu}N are realized, facilitating strong actuation with ultralow dissipation. A scanning probe microscope is implemented, capable of characterizing the mechanical modes. The integration of electrical actuation into optomechanical devices is an enabling step toward the regime of quantum nonlinear dynamics and provides capabilities for quantum control of mechanical motion.

  14. System and Method for Tensioning a Robotically Actuated Tendon

    NASA Technical Reports Server (NTRS)

    Reiland, Matthew J. (Inventor); Diftler, Myron A. (Inventor)

    2013-01-01

    A tendon tensioning system includes a tendon having a proximal end and a distal end, an actuator, and a motor controller. The actuator may include a drive screw and a motor, and may be coupled with the proximal end of the tendon and configured to apply a tension through the tendon in response to an electrical current. The motor controller may be electrically coupled with the actuator, and configured to provide an electrical current having a first amplitude to the actuator until a stall tension is achieved through the tendon; provide a pulse current to the actuator following the achievement of the stall tension, where the amplitude of the pulse current is greater than the first amplitude, and return the motor to a steady state holding current following the conclusion of the pulse current.

  15. Sensor-actuator system for dynamic chloride ion determination.

    PubMed

    de Graaf, Derk Balthazar; Abbas, Yawar; Gerrit Bomer, Johan; Olthuis, Wouter; van den Berg, Albert

    2015-08-12

    Chloride is a crucial anion for various analytical applications from biological to environmental applications. In order to measure the chloride ion concentration, a measurement system is needed which can detect this concentration for prolonged times reliably. Chronopotentiometry is a technique which does not need a long term stable reference electrode and is therefore very suitable for prolonged ion concentration measurements. As the used electrode might be fouled by reaction products, this work focuses on a chronopotentiometric approach with a separated sensing electrode (sensor) and actuating electrode (actuator). Both actuation and sensor electrode are made of Ag/AgCl. A constant current is applied to the actuator and will start the reaction between Ag and Cl-, while the resulting Cl- ion concentration change is observed through the sensor, which is placed close to the actuator. The time it takes to locally deplete the Cl- ions is called transition time. Experiments were performed to verify the feasibility of this approach. The performed experiments show that the sensor detects the local concentration changes resulting from the current applied to the actuator. A linear relation between the Cl- ion concentration and the square root of the transition time was observed, just as was predicted by theory. The calibration curves for different chips showed that both a larger sensor and a larger distance between sensor and actuator resulted in a larger time delay between the transition time detected at the actuator and the sensor.

  16. Hydraulically-actuated operating system for an electric circuit breaker

    DOEpatents

    Barkan, Philip; Imam, Imdad

    1978-01-01

    This hydraulically-actuated operating system comprises a cylinder, a piston movable therein in an opening direction to open a circuit breaker, and an accumulator for supplying pressurized liquid to a piston-actuating space within the cylinder. A normally-closed valve between the accumulator and the actuating space is openable to allow pressurized liquid from the accumulator to flow through the valve into the actuating space to drive the piston in an opening direction. A vent is located hydraulically between the actuating space and the valve for affording communication between said actuating space and a low pressure region. Flow control means is provided for restricting leakage through said vent to a rate that prevents said leakage from substantially detracting from the development of pressure within said actuatng space during the period from initial opening of the valve to the time when said piston has moved through most of its opening stroke. Following such period and while the valve is still open, said flow control means allows effective leakage through said vent. The accumulator has a limited capacity that results in the pressure within said actuating space decaying promptly to a low value as a result of effective leakage through said vent after the piston has moved through a circuit-breaker opening stroke and while the valve is in its open state. Means is provided for resetting the valve to its closed state in response to said pressure decay in the actuating space.

  17. Polarization Reconfigurable Patch Antenna Using Microelectromechanical Systems (MEMS) Actuators

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.; Chun, Donghoon; Katehi, Linda P. B.

    2002-01-01

    The paper demonstrates a nearly square patch antenna integrated with a novel microelectromechanical systems (MEMS) actuator for reconfiguring the polarization. Experimental results demonstrate that at a fixed frequency, the polarization can be reconfigured, from circular to linear.

  18. On reliable control system designs. Ph.D. Thesis; [actuators

    NASA Technical Reports Server (NTRS)

    Birdwell, J. D.

    1978-01-01

    A mathematical model for use in the design of reliable multivariable control systems is discussed with special emphasis on actuator failures and necessary actuator redundancy levels. The model consists of a linear time invariant discrete time dynamical system. Configuration changes in the system dynamics are governed by a Markov chain that includes transition probabilities from one configuration state to another. The performance index is a standard quadratic cost functional, over an infinite time interval. The actual system configuration can be deduced with a one step delay. The calculation of the optimal control law requires the solution of a set of highly coupled Riccati-like matrix difference equations. Results can be used for off-line studies relating the open loop dynamics, required performance, actuator mean time to failure, and functional or identical actuator redundancy, with and without feedback gain reconfiguration strategies.

  19. Engine having a variable valve actuation system

    DOEpatents

    Hefler, Gregory W.

    2005-10-12

    An engine has a cylinder head having a first surface and a second surface spaced from the first surface. A valve is moveably connected to the cylinder head. A rocker arm is connected to the valve, and a rocker shaft having a first location spaced a maximum distance from the cylinder head is connected to the rocker arm. A support member has and an actuator fluid passage network. The actuator fluid passage network defines a volume. The support member is connected to the cylinder head and is positioned such that a majority of the volume of the actuator fluid passage network is between the first location of the rocker shaft and the second surface of the cylinder head.

  20. Engine having a variable valve actuation system

    DOEpatents

    Hefler, Gregory W.

    2004-10-12

    An engine has a cylinder head having a first surface and a second surface spaced from the first surface. A valve is moveably connected to the cylinder head. A rocker arm is connected to the valve, and a rocker shaft having a first location spaced a maximum distance from the cylinder head is connected to the rocker arm. A support member has and an actuator fluid passage network. The actuator fluid passage network defines a volume. The support member is connected to the cylinder head and is positioned such that a majority of the volume of the actuator fluid passage network is between the first location of the rocker shaft and the second surface of the cylinder head.

  1. A wireless sequentially actuated microvalve system

    NASA Astrophysics Data System (ADS)

    Baek, Seung-Ki; Yoon, Yong-Kyu; Jeon, Hye-Seon; Seo, Soonmin; Park, Jung-Hwan

    2013-04-01

    A wireless microvalve system was fabricated based on induction heating for flow control in microfluidics by sequential valve opening. In this approach, we used paraffin wax as a flow plug, which can be changed from solid to liquid with adjacent heating elements operated by induction heating. Programmable opening of valves was devised by using different thermal responses of metal discs to a magnetic field. Copper and nickel discs with a diameter of 2.5 mm and various thicknesses (50, 100 and 200 µm) were prepared as heating elements by a laser cutting method, and they were integrated in the microfluidic channel as part of the microvalve. A calorimetric test was used to measure the thermal properties of the discs in terms of kinds of metal and disc thickness. Sequential openings of the microvalves were performed using the difference in the thermal response of 100 µm thick copper disc and 50 µm thick nickel disc for short-interval openings and 200 µm thick copper disc and 100-µm-thick nickel disc for long-interval openings. The thermal effect on fluid samples as a result of induction heating of the discs was studied by investigating lysozyme denaturation. More heat was generated in heating elements made of copper than in those made of nickel, implying differences in the thermal response of heating elements made of copper and nickel. Also, the thickness of the heating elements affected the thermal response in the elements. Valve openings for short intervals of 1-5 s and long intervals of 15-23 s were achieved by using two sets of heating elements. There was no significant change in lysozyme activity by increasing the temperature of the heating discs. This study demonstrates that a wireless sequentially actuated microvalve system can provide programmed valve opening, portability, ease of fabrication and operation, disposability, and low cost.

  2. Integrated actuation system for individual control of helicopter rotor blades

    NASA Astrophysics Data System (ADS)

    Bushko, Dariusz A.; Fenn, Ralph C.; Gerver, Michael J.; Berry, John R.; Phillips, Frank; Merkley, Donald J.

    1996-05-01

    The unique configuration of the rotorcraft generates problems unknown to fixed wing aircraft. These problems include high vibration and noise levels. This paper presents the development and test results of a Terfenol-D based actuator designed to operate in an individual blade control system in order to reduce vibration and noise and increase performance on Army UH- 60A helicopter. The full-scale, magnetostrictive, Terfenol-D based actuator was tested on a specially designed testbed that simulated operational conditions of a helicopter blade in the laboratory. Tests of actuator performance (strike, force moment, bandwidth, fatigue life under operational loading) were performed.

  3. Sequential growth for lifetime extension in biomimetic polypyrrole actuator systems

    NASA Astrophysics Data System (ADS)

    Sarrazin, J. C.; Mascaro, Stephen A.

    2015-04-01

    Electroactive polymers (EAPs) present prospective use in actuation and manipulation devices due to their low electrical activation requirements, biocompatibility, and mechanical performance. One of the main drawbacks with EAP actuators is a decrease in performance over extended periods of operation caused by over-oxidation of the polymer and general polymer degradation. Synthesis of the EAP material, polypyrrole with an embedded metal helix allows for sequential growth of the polymer during operation. The helical metal electrode acts as a scaffolding to support the polymer, and direct the 3-dimensional change in volume of the polymer along the axis of the helix during oxidative and reductive cycling. The metal helix also provides a working metal electrode through the entire length of the polymer actuator to distribute charge for actuation, as well as for sequential growth steps during the lifetime of operation of the polymer. This work demonstrates the method of sequential growth can be utilized after extended periods of use to partially restore electrical and mechanical performance of polypyrrole actuators. Since the actuation must be temporarily stopped to allow for a sequential growth cycle to be performed and reverse some of the polymer degradation, these actuator systems more closely mimic natural muscle in their analogous maintenance and repair.

  4. Microelectromechanical Systems (MEMS) Actuator for Reconfigurable Patch Antenna Demonstrated

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.

    2001-01-01

    A microstrip patch antenna with two contact actuators along the radiating edges for frequency reconfiguration was demonstrated at K-band frequencies. The layout of the antenna is shown in the following figure. This antenna has the following advantages over conventional semiconductor varactor-diode-tuned patch antennas: 1. By eliminating the semiconductor diode and its nonlinear I-V characteristics, the antenna minimizes intermodulation signal distortion. This is particularly important in digital wireless systems, which are sensitive to intersymbol interference caused by intermodulation products. 2. Because the MEMS actuator is an electrostatic device, it does not draw any current during operation and, hence, requires a negligible amount of power for actuation. This is an important advantage for hand-held, battery-operated, portable wireless systems since the battery does not need to be charged frequently. 3. The MEMS actuator does not require any special epitaxial layers as in the case of diodes and, hence, is cost effective.

  5. A latchable thermally activated phase change actuator for microfluidic systems

    NASA Astrophysics Data System (ADS)

    Richter, Christiane; Sachsenheimer, Kai; Rapp, Bastian E.

    2016-03-01

    Complex microfluidic systems often require a high number of individually controllable active components like valves and pumps. In this paper we present the development and optimization of a latchable thermally controlled phase change actuator which uses a solid/liquid phase transition of a phase change medium and the displacement of the liquid phase change medium to change and stabilize the two states of the actuator. Because the phase change is triggered by heat produced with ohmic resistors the used control signal is an electrical signal. In contrast to pneumatically activated membrane valves this concept allows the individual control of several dozen actuators with only two external pressure lines. Within this paper we show the general working principle of the actuator and demonstrate its general function and the scalability of the concept at an example of four actuators. Additionally we present the complete results of our studies to optimize the response behavior of the actuator - the influence of the heating power as well as the used phase change medium on melting and solidifying times.

  6. Dual-Actuator Active Vibration-Control System

    NASA Technical Reports Server (NTRS)

    Kascak, Albert F.; Kiraly, Louis J.; Montague, Gerald T.; Palazzolo, Alan B.; Manchala, Daniel

    1994-01-01

    Dual-actuator active vibration-control (DAAVC) system is developmental system of type described in "Active Vibration Dampers for Rotating Machinery" (LEW-15427). System features sensors and actuators positioned and oriented at bearings to measure and counteract vibrations of shaft along either of two axes perpendicular to axis of rotation. Effective in damping vibrations of helicopter-engine test stand, making it safer to operate engine at speeds near and above first resonance of engine/test-stand system. Opens new opportunities for engine designers to draw more power from engine, and concept applicable to other rotating machines.

  7. Bumpless switching control for switched systems with partial actuator failures

    NASA Astrophysics Data System (ADS)

    Qi, Yiwen; Bao, Wen; Zhang, Qingxin; Chang, Juntao

    2016-11-01

    This study is concerned with the bumpless transfer problem for switched systems with partial actuator failures, in order to obtain smooth system performance output transition. Taking into account that the system requires a controller switching from current sub-controller to a fault-tolerant sub-controller after actuator fault. And bumpless transfer for control input cannot be traditionally designed when the actuator fault occurs, while performance smoothing can be considered and it is actually the ultimate goal of bumpless transfer. Specifically, the actuator fault model is firstly established and partial actuator fault is considered. Then, the system performance output signal is deemed as the main design variable of bumpless transfer, and closed-loop control systems both previous and after controller switching are constructed. Moreover, by using model matching thought and the adaptive sliding mode control technique, a bumpless transfer compensator design strategy is given to drive the performance output variable (after controller switching) to track the one of reference model. At last, simulation results of numeric and application examples demonstrate the effectiveness of the proposed bumpless transfer strategy.

  8. Microseconds-scale magnetic actuators system for plasma feedback stabilization

    NASA Astrophysics Data System (ADS)

    Kogan, K.; Be'ery, I.; Seemann, O.

    2016-10-01

    Many magnetic confinement machines use active feedback stabilization with magnetic actuators. We present a novel magnetic actuators system with a response time much faster than previous ones, making it capable of coping with the fast plasma instabilities. The system achieved a response time of 3 μs with maximal current of 500 A in a coil with inductance of 5.2 μH. The system is based on commercial solid-state switches and FPGA state machine, making it easily scalable to higher currents or higher inductivity.

  9. A Hybrid Actuation System Demonstrating Significantly Enhanced Electromechanical Performance

    NASA Technical Reports Server (NTRS)

    Su, Ji; Xu, Tian-Bing; Zhang, Shujun; Shrout, Thomas R.; Zhang, Qiming

    2004-01-01

    A hybrid actuation system (HYBAS) utilizing advantages of a combination of electromechanical responses of an electroactive polymer (EAP), an electrostrictive copolymer, and an electroactive ceramic single crystal, PZN-PT single crystal, has been developed. The system employs the contribution of the actuation elements cooperatively and exhibits a significantly enhanced electromechanical performance compared to the performances of the device made of each constituting material, the electroactive polymer or the ceramic single crystal, individually. The theoretical modeling of the performances of the HYBAS is in good agreement with experimental observation. The consistence between the theoretical modeling and experimental test make the design concept an effective route for the development of high performance actuating devices for many applications. The theoretical modeling, fabrication of the HYBAS and the initial experimental results will be presented and discussed.

  10. A voice-actuated wind tunnel model leak checking system

    NASA Technical Reports Server (NTRS)

    Larson, W. E.

    1985-01-01

    A voice-actuated wind tunnel model leak checking system was developed. The system uses a voice recognition and response unit to interact with the technician along with a graphics terminal to provide the technician with visual feedback while checking a model for leaks.

  11. Employment of a porous gold actuator in ISFET-based coulometric sensor-actuator systems with application to protein characterization

    NASA Astrophysics Data System (ADS)

    Luo, Jiang

    1993-01-01

    Technological and theoretical aspects of the development and application of ISFET based coulometric sensor-actuator systems are described. An application of such a system to the characterization of proteins is suggested. Diffusion and migration processes at the coulometric sensor-actuator systems with a planar actuator in the application of acid base titration were studied. To minimize the delay time and to limit the diffusion of the species, a porous noble metal actuator is proposed, instead of a planar one, closely covering the gate of the ISFET. The adaptation of the conventional ISFET technology, by which a flat ISFET is proposed and fabricated, is described. An analytical model to describe the developed ISFET based coulometric sensor-actuator systems with gate-covering porous actuator is proposed. A way to operate the developed coulometric sensor-actuator system for a dynamical measurement of the buffer capacity of an analyte is introduced. The buffer capacity as a distinct parameter to characterize proteins was measured. The preliminary results obtained from the measurement of lysozyme and ribonuclease showed different buffer capacities at different pH values. More studies are necessary to further investigate the applicability of this method to characterize proteins.

  12. Development of a miniature actuator/controller system

    NASA Technical Reports Server (NTRS)

    Stanley, Scott P.

    1995-01-01

    Development of new products is often hampered or prevented by the cost and resource commitments required by a traditional engineering approach. Schaeffer Magnetics, Inc. identified the potential need for a miniature incremental actuator with an integrated controller but did not want the development to be subject to the obstacles inherent in the traditional approach. In response a new approach - the Pathfinder Engineering Program (PEP) - was developed to streamline new product generation and improve product quality. The actuator/controller system resulting from implementation of this new procedure is an exceptionally compact and self-contained device with many applications.

  13. 14 CFR 33.72 - Hydraulic actuating systems.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Hydraulic actuating systems. 33.72 Section 33.72 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.72...

  14. Reconfigurable Array Antenna Using Microelectromechanical Systems (MEMS) Actuators

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.; Chun, Donghoon; Katehi, Linda P. B.

    2001-01-01

    The paper demonstrates a patch antenna integrated with a novel microelectromechanical systems (MEMS) actuator for reconfiguring the operating frequency. Experimental results demonstrate that the center frequency can be reconfigured by as much as 1.6 percent of the nominal operating frequency at K-Band In addition, a novel on-wafer antenna pattern measurement technique is demonstrated.

  15. 14 CFR 33.72 - Hydraulic actuating systems.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Hydraulic actuating systems. 33.72 Section 33.72 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.72...

  16. 14 CFR 33.72 - Hydraulic actuating systems.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Hydraulic actuating systems. 33.72 Section 33.72 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.72...

  17. 14 CFR 33.72 - Hydraulic actuating systems.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Hydraulic actuating systems. 33.72 Section 33.72 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.72...

  18. Structural/control system optimization with variable actuator masses

    NASA Technical Reports Server (NTRS)

    Jin, Ik M.; Sepulveda, Abdon E.

    1993-01-01

    A method is presented to integrate the design space for structural/control system optimization problems in the case of linear state feedback control. Nonstructural lumped masses and control system design variables as well as structural sizing variables are all treated equally as independent design variables in the optimization process. Structural and control design variable linking schemes are used in order to avoid a prohibitively large increase in the total number of independent design variables. When actuator masses are treated as nonstructural lumped mass design variables, special consideration is given to the relation between the transient peak responses and the required actuator masses which is formulated as a behavior constraint form. The original nonlinear mathematical programming problem based on a finite element formulation and linear state feedback is replaced by a sequence of explicit approximate problems exploiting various approximation concepts such as design variable linkings, temporary constraint deletion and first order Taylor series expansion of nonlinear behavior constraints in terms of intermediate design variables. Examples which involve a variety of dynamic behavior constraints (including constraints on closed-loop eigenvalues, peak transient displacements, peak actuator forces, and relations between the peak responses and the actuator masses) are effectively solved by using the method presented.

  19. Conducting IPN actuator/sensor for biomimetic vibrissa system

    NASA Astrophysics Data System (ADS)

    Festin, N.; Plesse, C.; Pirim, P.; Chevrot, C.; Vidal, F.

    2014-03-01

    Electroactive polymers, or EAPs, are polymers that exhibit a change in size or shape when stimulated by an electric field. The most common applications of this type of material are in actuators and sensors. One promising technology is the elaboration of electronic conducting polymers based actuators with Interpenetrating Polymer Networks (IPNs) architecture. Their many advantageous properties as low working voltage, light weight and high lifetime make them very attractive for various applications including robotics. Conducting IPNs were fabricated by oxidative polymerization of 3,4-ethylenedioxythiophene within a flexible Solid Polymer Electrolytes (SPE) combining poly(ethylene oxide) and Nitrile Butadiene Rubber. SPE mechanical properties and ionic conductivities in the presence of 1-ethyl-3- methylimidazolium bis-(trifluoromethylsulfonyl)-imide (EMITFSI) have been characterized. The presence of the elastomer within the SPE greatly improves the actuator performances. The free strain as well as the blocking force was characterized as a function of the actuator length. The sensing properties of those conducting IPNs allow their integration into a biomimetic perception prototype: a system mimicking the tactile perception of rat vibrissae.

  20. Flight Control System Design with Rate Saturating Actuators

    NASA Technical Reports Server (NTRS)

    Hess, R. A.; Snell, S. A.

    1997-01-01

    Actuator rate saturation is an important factor adversely affecting the stability and performance of aircraft flight control systems. It has been identified as a catalyst in pilot-induced oscillations, some of which have been catastrophic. A simple design technique is described that utilizes software rate limiters to improve the performance of control systems operating in the presence of actuator rate saturation. As described, the technique requires control effectors to be ganged such that any effector is driven by only a single compensated error signal. Using an analysis of the steady-state behavior of the system, requirements are placed upon the type of the loop transmissions and compensators in the proposed technique. Application of the technique to the design of a multi-input/multi-output, lateral-directional control system for a simple model of a high-performance fighter is demonstrated as are the stability and performance improvements that can accrue with the technique.

  1. Piezoelectric Multilayer-Stacked Hybrid Actuation/Transduction System

    NASA Technical Reports Server (NTRS)

    Xu, Tian-Bing (Inventor); Jiang, Xiaoning (Inventor); Su, Ji (Inventor)

    2014-01-01

    A novel full piezoelectric multilayer stacked hybrid actuation/transduction system. The system demonstrates significantly-enhanced electromechanical performance by utilizing the cooperative contributions of the electromechanical responses of multilayer stacked negative and positive strain components. Both experimental and theoretical studies indicate that for this system, the displacement is over three times that of a same-sized conventional flextensional actuator/transducer. The system consists of at least 2 layers which include electromechanically active components. The layers are arranged such that when electric power is applied, one layer contracts in a transverse direction while the second layer expands in a transverse direction which is perpendicular to the transverse direction of the first layer. An alternate embodiment includes a third layer. In this embodiment, the outer two layers contract in parallel transverse directions while the middle layer expands in a transverse direction which is perpendicular to the transverse direction of the outer layers.

  2. Intelligent fault diagnosis and failure management of flight control actuation systems

    NASA Technical Reports Server (NTRS)

    Bonnice, William F.; Baker, Walter

    1988-01-01

    The real-time fault diagnosis and failure management (FDFM) of current operational and experimental dual tandem aircraft flight control system actuators was investigated. Dual tandem actuators were studied because of the active FDFM capability required to manage the redundancy of these actuators. The FDFM methods used on current dual tandem actuators were determined by examining six specific actuators. The FDFM capability on these six actuators was also evaluated. One approach for improving the FDFM capability on dual tandem actuators may be through the application of artificial intelligence (AI) technology. Existing AI approaches and applications of FDFM were examined and evaluated. Based on the general survey of AI FDFM approaches, the potential role of AI technology for real-time actuator FDFM was determined. Finally, FDFM and maintainability improvements for dual tandem actuators were recommended.

  3. Finite Energy and Bounded Actuator Attacks on Cyber-Physical Systems

    SciTech Connect

    Djouadi, Seddik M; Melin, Alexander M; Ferragut, Erik M; Laska, Jason A; Dong, Jin; Drira, Anis

    2015-01-01

    As control system networks are being connected to enterprise level networks for remote monitoring, operation, and system-wide performance optimization, these same connections are providing vulnerabilities that can be exploited by malicious actors for attack, financial gain, and theft of intellectual property. Much effort in cyber-physical system (CPS) protection has focused on protecting the borders of the system through traditional information security techniques. Less effort has been applied to the protection of cyber-physical systems from intelligent attacks launched after an attacker has defeated the information security protections to gain access to the control system. In this paper, attacks on actuator signals are analyzed from a system theoretic context. The threat surface is classified into finite energy and bounded attacks. These two broad classes encompass a large range of potential attacks. The effect of theses attacks on a linear quadratic (LQ) control are analyzed, and the optimal actuator attacks for both finite and infinite horizon LQ control are derived, therefore the worst case attack signals are obtained. The closed-loop system under the optimal attack signals is given and a numerical example illustrating the effect of an optimal bounded attack is provided.

  4. Three Dimensional Modeling of an MRI Actuated Steerable Catheter System.

    PubMed

    Liu, Taoming; Cavuşoğlu, M Cenk

    2014-01-01

    This paper presents the three dimensional kinematic modeling of a novel steerable robotic ablation catheter system. The catheter, embedded with a set of current-carrying micro-coils, is actuated by the magnetic forces generated by the magnetic field of the MRI scanner. This paper develops a 3D model of the MRI actuated steerable catheter system by using finite differences approach. For each finite segment, a quasi-static torque-deflection equilibrium equation is calculated using beam theory. By using the deflection displacements and torsion angles, the kinematic modeling of the catheter system is derived. The proposed models are evaluated by comparing the simulation results of the proposed model with the experimental results of a proof-of-concept prototype. PMID:25328804

  5. Transfer matrix method for multibody systems for piezoelectric stack actuators

    NASA Astrophysics Data System (ADS)

    Zhu, Wei; Chen, Gangli; Bian, Leixiang; Rui, Xiaoting

    2014-09-01

    In order to achieve a large displacement output from a piezoelectric actuator, we realized the piezoelectric stack actuator (PSA) by mechanically layering/stacking multi-chip piezoelectric wafers in a series and electrically connecting the electrodes in parallel. In this paper, in order to accurately model the hysteresis and the dynamic characteristics of a PSA, the transfer matrix method for multibody systems (MSTMM) was adopted to describe the dynamic characteristics, and the Bouc-Wen hysteresis operator was used to represent the hysteresis. The vibration characteristics of a PSA and a piezo-actuated positioning mechanism (PPM) are derived and analyzed by the MSTMM; then, the dynamic responses of the PSA and the PPM are calculated. The experimental results show that the new method can accurately portray the hysteresis and the dynamic characteristics of a PSA and a PPM. On one hand, if we use this method to model the dynamic response of the PSA and the PPM, the PSA can be considered as a flexible body, as opposed to a mass-spring-damper system, which is in better agreement with the actual condition. On the other hand, the global dynamics equation is not needed for the study of system dynamics, and the dynamics equation has a small-sized matrix and a higher computational speed. Therefore, this method gives a broad range of possibilities for model-based controller design.

  6. Piezo stack actuation control system for sperm injection

    NASA Astrophysics Data System (ADS)

    Tan, K. K.; Putra, A. S.

    2005-12-01

    Among the electric motor drives, the piezoelectric actuator (PA) is one drive which is becoming very popular in high precision biomedical applications, such as intracytoplasmic sperm injection. The main benefits of a PA include low thermal losses and, most importantly, the high precision and accuracy achievable consequent of the driect drive principle. One major source of uncertainties in PA control design is the hysteresis behavior which yields a rate-independent lag and residual displacement near zero input, reducing the precision of the actuators. Due to the typical precision positioning requirements and low offset tolerance of PA applications, the design and control of these systems, under the influence of these uncertainties, is particularly challenging since conventional PID control usually does not suffice in these application domains to meet the stringent performance requirements. In this paper, we consider the design and realization of a piezo stack actuator which is capable of linear motion and non-full rotation to fulfill the stringent requirements associated with sperm injection applications. A complementary precise control system is developed employing a robust adaptive control algorithm to reject the hysteresis phenomenon associated with general PAs and to achieve rapid and highly precise positioning. The controller comprises of a PID feedback component and an adaptive component for hysteresis compensation. The adaptive component is continuously refined based on just prevailing input and output signals. In the paper, it will be proven that the tracking error can asymptotically converge to zero. In addition, analytical quantification is given to illustrate the improvement of the system's transient performance. Real-time experimental results verify the effectiveness of the proposed micro actuator for high precision motion trajectory tracking in intracytoplasmic sperm injection using mice eggs.

  7. Position control system for use with micromechanical actuators

    DOEpatents

    Guckel, Henry; Stiers, Eric W.

    2000-01-01

    A positioning system adapted for use with micromechanical actuators provides feedback control of the position of the movable element of the actuator utilizing a low Q sensing coil. The effective inductance of the sensing coil changes with position of the movable element to change the frequency of oscillation of a variable oscillator. The output of the variable oscillator is compared in a phase detector to a reference oscillator signal. The phase detector provides a pulsed output having a pulse duty cycle related to the phase or frequency difference between the oscillator signals. The output of the phase detector is provided to a drive coil which applies a magnetic force to the movable element which balances the force of a spring. The movable element can be displaced to a new position by changing the frequency of the reference oscillator.

  8. Development of actuation system for artificial cilia with magnetic elastomer

    NASA Astrophysics Data System (ADS)

    Tsumori, Fujio; Saijou, Akinori; Osada, Toshiko; Miura, Hideshi

    2015-06-01

    In this paper, we describe the development of magnetically actuated artificial cilia. Natural cilia are a highly efficient device that produces flow under a small-Reynolds-number state. There are two important characteristics of natural cilia; one is asymmetric movement, which is composed of effective and recovery strokes, and the other is the phase difference of a stroke in each cilium in an array that will produce a metachronal wave. In this paper, we propose an actuation system for artificial cilia composed of a silicone elastomer and multiparticle chains of a magnetic material. The applied magnetic field is controlled by rotation of a permanent magnet. This rotating magnetic field induced an asymmetric movement similar to that of a natural cilium. We also changed the orientation angle of multiparticle chains to control the phase difference of a stroke in each artificial cilium. This technique would help to realize metachronal waves of artificial cilia.

  9. Quick actuating closure and handling system

    NASA Technical Reports Server (NTRS)

    Allred, Johnny W.; White, Dorsey E., III; Updike, Benjamin T.; Gregory, Peyton B.

    1988-01-01

    A quick activating closure and handling system, which utilizes conical sections for locking, was developed to allow quick access to the combustor internal components of the 8 ft High Temperature Tunnel. These critical components include the existing methane spraybar, a transpiration cooled nozzle and the new liquid oxygen (LOX) injection system housed within the combustor. A substantial cost savings will be realized once the mechanism is installed since it will substantially reduce the access time and increase the time available for conducting wind tunnel tests. A need exists for more frequent inspections when the wind tunnel operates at the more severe conditions generated by using LOX in the combustor. A loads analysis and a structural (finite element) analysis were conducted to verify that the new closure system is compatible with the existing pressure shell. In addition, strain gages were placed on the pressure vessel to verify how the pressure shell reacts to transient pressure loads. A scale model of the new closure system was built to verify the operation of the conical sections in the locking mechanisms.

  10. Integrating Sensory/Actuation Systems in Agricultural Vehicles

    PubMed Central

    Emmi, Luis; Gonzalez-de-Soto, Mariano; Pajares, Gonzalo; Gonzalez-de-Santos, Pablo

    2014-01-01

    In recent years, there have been major advances in the development of new and more powerful perception systems for agriculture, such as computer-vision and global positioning systems. Due to these advances, the automation of agricultural tasks has received an important stimulus, especially in the area of selective weed control where high precision is essential for the proper use of resources and the implementation of more efficient treatments. Such autonomous agricultural systems incorporate and integrate perception systems for acquiring information from the environment, decision-making systems for interpreting and analyzing such information, and actuation systems that are responsible for performing the agricultural operations. These systems consist of different sensors, actuators, and computers that work synchronously in a specific architecture for the intended purpose. The main contribution of this paper is the selection, arrangement, integration, and synchronization of these systems to form a whole autonomous vehicle for agricultural applications. This type of vehicle has attracted growing interest, not only for researchers but also for manufacturers and farmers. The experimental results demonstrate the success and performance of the integrated system in guidance and weed control tasks in a maize field, indicating its utility and efficiency. The whole system is sufficiently flexible for use in other agricultural tasks with little effort and is another important contribution in the field of autonomous agricultural vehicles. PMID:24577525

  11. Integrating sensory/actuation systems in agricultural vehicles.

    PubMed

    Emmi, Luis; Gonzalez-de-Soto, Mariano; Pajares, Gonzalo; Gonzalez-de-Santos, Pablo

    2014-01-01

    In recent years, there have been major advances in the development of new and more powerful perception systems for agriculture, such as computer-vision and global positioning systems. Due to these advances, the automation of agricultural tasks has received an important stimulus, especially in the area of selective weed control where high precision is essential for the proper use of resources and the implementation of more efficient treatments. Such autonomous agricultural systems incorporate and integrate perception systems for acquiring information from the environment, decision-making systems for interpreting and analyzing such information, and actuation systems that are responsible for performing the agricultural operations. These systems consist of different sensors, actuators, and computers that work synchronously in a specific architecture for the intended purpose. The main contribution of this paper is the selection, arrangement, integration, and synchronization of these systems to form a whole autonomous vehicle for agricultural applications. This type of vehicle has attracted growing interest, not only for researchers but also for manufacturers and farmers. The experimental results demonstrate the success and performance of the integrated system in guidance and weed control tasks in a maize field, indicating its utility and efficiency. The whole system is sufficiently flexible for use in other agricultural tasks with little effort and is another important contribution in the field of autonomous agricultural vehicles. PMID:24577525

  12. Integrating sensory/actuation systems in agricultural vehicles.

    PubMed

    Emmi, Luis; Gonzalez-de-Soto, Mariano; Pajares, Gonzalo; Gonzalez-de-Santos, Pablo

    2014-02-26

    In recent years, there have been major advances in the development of new and more powerful perception systems for agriculture, such as computer-vision and global positioning systems. Due to these advances, the automation of agricultural tasks has received an important stimulus, especially in the area of selective weed control where high precision is essential for the proper use of resources and the implementation of more efficient treatments. Such autonomous agricultural systems incorporate and integrate perception systems for acquiring information from the environment, decision-making systems for interpreting and analyzing such information, and actuation systems that are responsible for performing the agricultural operations. These systems consist of different sensors, actuators, and computers that work synchronously in a specific architecture for the intended purpose. The main contribution of this paper is the selection, arrangement, integration, and synchronization of these systems to form a whole autonomous vehicle for agricultural applications. This type of vehicle has attracted growing interest, not only for researchers but also for manufacturers and farmers. The experimental results demonstrate the success and performance of the integrated system in guidance and weed control tasks in a maize field, indicating its utility and efficiency. The whole system is sufficiently flexible for use in other agricultural tasks with little effort and is another important contribution in the field of autonomous agricultural vehicles.

  13. High speed hydraulically-actuated operating system for an electric circuit breaker

    DOEpatents

    Iman, Imdad

    1983-06-07

    This hydraulically-actuated operating system comprises a cylinder, a piston movable therein in an opening direction to open a circuit breaker, and an accumulator for supplying pressurized liquid to a breaker-opening piston-actuating space within the cylinder. A normally-closed valve between the accumulator and the actuating space is openable to allow pressurized liquid from the accumulator to flow through the valve into the actuating space to drive the piston in an opening direction. A dashpotting mechanism operating separately from the hydraulic actuating system is provided, thereby reducing flow restriction interference with breaker opening.

  14. High speed hydraulically-actuated operating system for an electric circuit breaker

    DOEpatents

    Iman, I.

    1983-06-07

    This hydraulically-actuated operating system comprises a cylinder, a piston movable therein in an opening direction to open a circuit breaker, and an accumulator for supplying pressurized liquid to a breaker-opening piston-actuating space within the cylinder. A normally-closed valve between the accumulator and the actuating space is openable to allow pressurized liquid from the accumulator to flow through the valve into the actuating space to drive the piston in an opening direction. A dashpotting mechanism operating separately from the hydraulic actuating system is provided, thereby reducing flow restriction interference with breaker opening. 3 figs.

  15. Flight Test Experience with an Electromechanical Actuator on the F-18 Systems Research Aircraft

    NASA Technical Reports Server (NTRS)

    Jensen, Stephen C.; Jenney, Gavin D.; Raymond, Bruce; Dawson, David; Flick, Brad (Technical Monitor)

    2000-01-01

    Development of reliable power-by-wire actuation systems for both aeronautical and space applications has been sought recently to eliminate hydraulic systems from aircraft and spacecraft and thus improve safety, efficiency, reliability, and maintainability. The Electrically Powered Actuation Design (EPAD) program was a joint effort between the Air Force, Navy, and NASA to develop and fly a series of actuators validating power-by-wire actuation technology on a primary flight control surface of a tactical aircraft. To achieve this goal, each of the EPAD actuators was installed in place of the standard hydraulic actuator on the left aileron of the NASA F/A-18B Systems Research Aircraft (SRA) and flown throughout the SRA flight envelope. Numerous parameters were recorded, and overall actuator performance was compared with the performance of the standard hydraulic actuator on the opposite wing. This paper discusses the integration and testing of the EPAD electromechanical actuator (EMA) on the SRA. The architecture of the EMA system is discussed, as well as its integration with the F/A-18 Flight Control System. The flight test program is described, and actuator performance is shown to be very close to that of the standard hydraulic actuator it replaced. Lessons learned during this program are presented and discussed, as well as suggestions for future research.

  16. Flight Test Experience With an Electromechanical Actuator on the F-18 Systems Research Aircraft

    NASA Technical Reports Server (NTRS)

    Jensen, Stephen C.; Jenney, Gavin D.; Raymond, Bruce; Dawson, David

    2000-01-01

    Development of reliable power-by-wire actuation systems for both aeronautical and space applications has been sought recently to eliminate hydraulic systems from aircraft and spacecraft and thus improve safety, efficiency, reliability, and maintainability. The Electrically Powered Actuation Design (EPAD) program was a joint effort between the Air Force, Navy, and NASA to develop and fly a series of actuators validating power-by-wire actuation technology on a primary flight control surface of a tactical aircraft. To achieve this goal, each of the EPAD actuators was installed in place of the standard hydraulic actuator on the left aileron of the NASA F/A-18B Systems Research Aircraft (SRA) and flown throughout the SRA flight envelope. Numerous parameters were recorded, and overall actuator performance was compared with the performance of the standard hydraulic actuator on the opposite wing. This paper discusses the integration and testing of the EPAD electromechanical actuator (EMA) on the SRA. The architecture of the EMA system is discussed, as well as its integration with the F/A-18 Flight Control System. The flight test program is described, and actuator performance is shown to be very close to that of the standard hydraulic actuator it replaced. Lessons learned during this program are presented and discussed, as well as suggestions for future research.

  17. Performance of an Electro-Hydrostatic Actuator on the F-18 Systems Research Aircraft

    NASA Technical Reports Server (NTRS)

    Navarro, Robert

    1997-01-01

    An electro-hydrostatic actuator was evaluated at NASA Dryden Flight Research Center, Edwards, California. The primary goal of testing this actuator system was the flight demonstration of power-by-wire technology on a primary flight control surface. The electro-hydrostatic actuator uses an electric motor to drive a hydraulic pump and relies on local hydraulics for force transmission. This actuator replaced the F-18 standard left aileron actuator on the F-18 Systems Research Aircraft and was evaluated throughout the Systems Research Aircraft flight envelope. As of July 24, 1997 the electro-hydrostatic actuator had accumulated 23.5 hours of flight time. This paper presents the electro-hydrostatic actuator system configuration and component description, ground and flight test plans, ground and flight test results, and lessons learned. This actuator performs as well as the standard actuator and has more load capability than required by aileron actuator specifications of McDonnell- Douglas Aircraft, St. Louis, Missouri. The electro-hydrostatic actuator system passed all of its ground tests with the exception of one power-off test during unloaded dynamic cycling.

  18. A portable air jet actuator device for mechanical system identification.

    PubMed

    Belden, Jesse; Staats, Wayne L; Mazumdar, Anirban; Hunter, Ian W

    2011-03-01

    System identification of limb mechanics can help diagnose ailments and can aid in the optimization of robotic limb control parameters and designs. An interesting fluid phenomenon--the Coandă effect--is utilized in a portable actuator to provide a stochastic binary force disturbance to a limb system. The design of the actuator is approached with the goal of creating a portable device which could be deployed on human or robotic limbs for in situ mechanical system identification. The viability of the device is demonstrated by identifying the parameters of an underdamped elastic beam system with fixed inertia and stiffness and variable damping. The nonparametric compliance impulse response yielded from the system identification is modeled as a second-order system and the resultant parameters are found to be in excellent agreement with those found using more traditional system identification techniques. The current design could be further miniaturized and developed as a portable, wireless, unrestrained mechanical system identification instrument for less intrusive and more widespread use. PMID:21456788

  19. A portable air jet actuator device for mechanical system identification

    NASA Astrophysics Data System (ADS)

    Belden, Jesse; Staats, Wayne L.; Mazumdar, Anirban; Hunter, Ian W.

    2011-03-01

    System identification of limb mechanics can help diagnose ailments and can aid in the optimization of robotic limb control parameters and designs. An interesting fluid phenomenon—the Coandă effect—is utilized in a portable actuator to provide a stochastic binary force disturbance to a limb system. The design of the actuator is approached with the goal of creating a portable device which could be deployed on human or robotic limbs for in situ mechanical system identification. The viability of the device is demonstrated by identifying the parameters of an underdamped elastic beam system with fixed inertia and stiffness and variable damping. The nonparametric compliance impulse response yielded from the system identification is modeled as a second-order system and the resultant parameters are found to be in excellent agreement with those found using more traditional system identification techniques. The current design could be further miniaturized and developed as a portable, wireless, unrestrained mechanical system identification instrument for less intrusive and more widespread use.

  20. Multivariable control systems with saturating actuators antireset windup strategies

    NASA Technical Reports Server (NTRS)

    Kapasouris, P.; Athans, M.

    1985-01-01

    Preliminary, promising, results for introducing antireset windup (ARW) properties in multivariable feedback control systems with multiple saturating actuator nonlinearities and integrating actions are presented. The ARW method introduces simple nonlinear feedback around the integrators. The multiloop circle criterion is used to derive sufficient conditions for closed-loop stability that employ frequency-domain singular value tests. The improvement in transient response due to the ARW feedback is demonstrated using a 2-input 2-outpurt control system based upon F-404 jet engine dynamics.

  1. System-Level Design of a Shape Memory Alloy Actuator for Active Clearance Control in the High-Pressure Turbine

    NASA Technical Reports Server (NTRS)

    DeCastro, Jonathan A.; Melcher, Kevin J.; Noebe, Ronald D.

    2005-01-01

    This paper describes results of a numerical analysis evaluating the feasibility of high-temperature shape memory alloys (HTSMA) for active clearance control actuation in the high-pressure turbine section of a modern turbofan engine. The prototype actuator concept considered here consists of parallel HTSMA wires attached to the shroud that is located on the exterior of the turbine case. A transient model of an HTSMA actuator was used to evaluate active clearance control at various operating points in a test bed aircraft engine simulation. For the engine under consideration, each actuator must be designed to counteract loads from 380 to 2000 lbf and displace at least 0.033 inches. Design results show that an actuator comprised of 10 wires 2 inches in length is adequate for control at critical engine operating points and still exhibits acceptable failsafe operability and cycle life. A proportional-integral-derivative (PID) controller with integrator windup protection was implemented to control clearance amidst engine transients during a normal mission. Simulation results show that the control system exhibits minimal variability in clearance control performance across the operating envelope. The final actuator design is sufficiently small to fit within the limited space outside the high-pressure turbine case and is shown to consume only small amounts of bleed air to adequately regulate temperature.

  2. Design and Integration of an Actuated Nose Strake Control System

    NASA Technical Reports Server (NTRS)

    Flick, Bradley C.; Thomson, Michael P.; Regenie, Victoria A.; Wichman, Keith D.; Pahle, Joseph W.; Earls, Michael R.

    1996-01-01

    Aircraft flight characteristics at high angles of attack can be improved by controlling vortices shed from the nose. These characteristics have been investigated with the integration of the actuated nose strakes for enhanced rolling (ANSER) control system into the NASA F-18 High Alpha Research Vehicle. Several hardware and software systems were developed to enable performance of the research goals. A strake interface box was developed to perform actuator control and failure detection outside the flight control computer. A three-mode ANSER control law was developed and installed in the Research Flight Control System. The thrust-vectoring mode does not command the strakes. The strakes and thrust-vectoring mode uses a combination of thrust vectoring and strakes for lateral- directional control, and strake mode uses strakes only for lateral-directional control. The system was integrated and tested in the Dryden Flight Research Center (DFRC) simulation for testing before installation in the aircraft. Performance of the ANSER system was monitored in real time during the 89-flight ANSER flight test program in the DFRC Mission Control Center. One discrepancy resulted in a set of research data not being obtained. The experiment was otherwise considered a success with the majority of the research objectives being met.

  3. OMS engine shutoff valve and actuation system design and evaluation. [for space shuttles

    NASA Technical Reports Server (NTRS)

    Wichmann, H.

    1974-01-01

    Shutoff valve and actuation system concepts that are most suitable for the Orbital Maneuvering Systems engine application were determined. Emphasis was placed on the ten year and 100 mission life requirement, propellant and propellant residue compatibility and weight. It was found that poppet or ball valves utilizing electric or electropneumatic actuation were most applicable. Preliminary design layouts of a number of valve and actuation concepts were prepared and analyzed to make the optimum concept selection. Pneumatic actuation systems were required to feature their own pneumatic supply so that for the quad redundant valve, it was necessary to include two pneumatic supply systems, one for each of the series legs of the quad redundant package. The requirement for the pneumatic package placed heavy reliability, weight, and maintenance penalties upon electropneumatic actuation systems. The two valve and actuation systems concepts selected featured electric torque motor operation and a poppet as well as a ball valve concept with a retractable seal.

  4. Applications catalog of pyrotechnically actuated devices/systems

    NASA Technical Reports Server (NTRS)

    Seeholzer, Thomas L.; Smith, Floyd Z.; Eastwood, Charles W.; Steffes, Paul R.

    1995-01-01

    A compilation of basic information on pyrotechnically actuated devices/systems used in NASA aerospace and aeronautic applications was formatted into a catalog. The intent is to provide (1) a quick reference digest of the types of operational pyro mechanisms and (2) a source of contacts for further details. Data on these items was furnished by the NASA Centers that developed and/or utilized such devices to perform specific functions on spacecraft, launch vehicles, aircraft, and ground support equipment. Information entries include an item title, user center name, commercial contractor/vendor, identifying part number(s), a basic figure, briefly described purpose and operation, previous usage, and operational limits/requirements.

  5. Understanding the Space Shuttle Main Engine Hydraulic Actuation System and Reviewing Its Evolution

    NASA Technical Reports Server (NTRS)

    McWade, Robert J.; Minor, Robert B.; McNutt, Leslie M.

    2010-01-01

    The complex engine start and thrust control requirements of the Space Shuttle Main Engine (SSME) require unique valve, actuator and control system hardware. The Hydraulic Actuation System (HAS) was designed, developed, and now operates to meet tight engine control requirement limits to assure safe, reliable and correct engine thrust at all times. The actuator is designed to be fail safe and fail operate in the areas where redundancy is important. The HAS has an additional pneumatic operating capability that insures a safe sequential closure of all actuators and propellant valves in the event of the loss of hydraulic system pressure or loss of electrical closed loop control of the actuator. The objective of this paper is to provide a complete description of the actuator s internal operating system, along with its interaction with all SSME system interfaces. Additionally the paper addresses the challenges, problems identified, and corrected, and lessons learned, during the course of the almost 35 years of engine operation.

  6. Electromagnetic variable degrees of freedom actuator systems and methods

    DOEpatents

    Montesanti, Richard C.; Trumper, David L.; Kirtley, Jr., James L.

    2009-02-17

    The present invention provides a variable reluctance actuator system and method that can be adapted for simultaneous rotation and translation of a moving element by applying a normal-direction magnetic flux on the moving element. In a beneficial example arrangement, the moving element includes a swing arm that carries a cutting tool at a set radius from an axis of rotation so as to produce a rotary fast tool servo that provides a tool motion in a direction substantially parallel to the surface-normal of a workpiece at the point of contact between the cutting tool and workpiece. An actuator rotates a swing arm such that a cutting tool moves toward and away from a mounted rotating workpiece in a controlled manner in order to machine the workpiece. Position sensors provide rotation and displacement information for a swing arm to a control system. A control system commands and coordinates motion of the fast tool servo with the motion of a spindle, rotating table, cross-feed slide, and in feed slide of a precision lathe.

  7. Full Piezoelectric Multilayer-Stacked Hybrid Actuation/Transduction Systems

    NASA Technical Reports Server (NTRS)

    Su, Ji; Jiang, Xiaoning; Zu, Tian-Bing

    2011-01-01

    The Stacked HYBATS (Hybrid Actuation/Transduction system) demonstrates significantly enhanced electromechanical performance by using the cooperative contributions of the electromechanical responses of multilayer, stacked negative strain components and positive strain components. Both experimental and theoretical studies indicate that, for Stacked HYBATS, the displacement is over three times that of a same-sized conventional flextensional actuator/transducer. The coupled resonance mode between positive strain and negative strain components of Stacked HYBATS is much stronger than the resonance of a single element actuation only when the effective lengths of the two kinds of elements match each other. Compared with the previously invented hybrid actuation system (HYBAS), the multilayer Stacked HYBATS can be designed to provide high mechanical load capability, low voltage driving, and a highly effective piezoelectric constant. The negative strain component will contract, and the positive strain component will expand in the length directions when an electric field is applied on the device. The interaction between the two elements makes an enhanced motion along the Z direction for Stacked-HYBATS. In order to dominate the dynamic length of Stacked-HYBATS by the negative strain component, the area of the cross-section for the negative strain component will be much larger than the total cross-section areas of the two positive strain components. The transverse strain is negative and longitudinal strain positive in inorganic materials, such as ceramics/single crystals. Different piezoelectric multilayer stack configurations can make a piezoelectric ceramic/single-crystal multilayer stack exhibit negative strain or positive strain at a certain direction without increasing the applied voltage. The difference of this innovation from the HYBAS is that all the elements can be made from one-of-a-kind materials. Stacked HYBATS can provide an extremely effective piezoelectric

  8. Design and modeling of new suspension system using direct drive servo-valve system actuated by piezostack actuator

    NASA Astrophysics Data System (ADS)

    Han, Chulhee; Kim, Wan Ho; Choi, Seung-Bok

    2016-04-01

    This paper proposes a new type of a direct-drive valve (DDV) suspension system for vehicle controlled by the piezostack actuator associated with displacement amplifier. In order to achieve this goal, a new type of controllable piezostack DDV damper is designed and its performance evaluation of damping force is undertaken. Next, a full vehicle suspension system consisting of sprung mass, spring, tire and the piezostack DDV damper is constructed. After deriving the governing equations of the motion for the proposed the piezostack DDV suspension system, the skyhook controller is implemented for the realization of the full vehicle. Analytical model of the whole suspension system is then derived and performance characteristics are analyzed through numerical simulation. Finally, vibration control responses of the vehicle suspension system such as vertical acceleration are evaluated under both bump and sine road conditions.

  9. Double-Acting Sleeve Muscle Actuator for Bio-Robotic Systems

    PubMed Central

    Zheng, Hao; Shen, Xiangrong

    2014-01-01

    This paper presents a new type of muscle-like actuator, namely double-acting (DA) sleeve muscle actuator, which is suitable for the actuation of biologically-inspired and biomedical robotic systems, especially those serving human-assistance purposes (prostheses, orthoses, etc.). Developed based on the traditional pneumatic muscle actuator, the new DA sleeve muscle incorporates a unique insert at the center. With the insert occupying the central portion of the internal volume, this new actuator enjoys multiple advantages relative to the traditional pneumatic muscle, including a consistent increase of force capacity over the entire range of motion, and a significant decrease of energy consumption in operation. Furthermore, the insert encompasses an additional chamber, which generates an extension force when pressurized. As such, this new actuator provides a unique bi-directional actuation capability, and, thus, has a potential to significantly simplify the design of a muscle actuator-powered robotic system. To demonstrate this new actuator concept, a prototype has been designed and fabricated, and experiments conducted on this prototype demonstrated the enhanced force capacity and the unique bi-directional actuation capability. PMID:25264492

  10. Magnetic actuator intended for left ventricular assist system

    NASA Astrophysics Data System (ADS)

    Saotome, H.; Okada, T.

    2006-04-01

    With the goal of developing an artificial heart, the authors fabricated a prototype pump employing a linear motion magnetic actuator, and carried out performance tests. The actuator is composed of two disk-shaped Nd-Fe-B magnets having a diameter of 80 mm and a thickness of 7 mm. The disks are magnetized in the direction normal to the circular surface, and are formed by semicircular pieces; one semicircle serves as a N pole and the other as a S pole. The magnets face each other in the actuator. One magnet is limited to spin around its axis while the second magnet is limited to move in linear motion along its axis. In this way, the circumferential rotation of one of the magnets produces reciprocating forces on the other magnet, causing it to move back and forth. This coupled action produces a pumping motion. Because the two magnets are magnetically coupled without any mechanical contact, the rotating magnet does not have to be implanted and should be placed outside the body. The rotating magnet is driven by a motor. The motor power is magnetically conveyed, via the rotating magnet, to the implanted linear motion magnet through the skin. The proposed system yields no problems with infection that would otherwise require careful treatment in a system employing a tube penetrating the skin for power transmission. Comparison of the proposed system with another system using a transcutaneous transformer shows that our system has good potential to occupy a smaller space in the body, because it obviates implantation of a secondary part of the transformer, a power supply, and armature windings. The dimensions of the trial pump are designed in accordance with the fluid mechanical specifications of a human left ventricle, by computing magnetic fields that provide the magnetic forces on the magnets. The output power of the trial pump, 1.0 W at 87 beats/min, is experimentally obtained under the pressure and flow conditions of water, 100 mm Hg and 4.5 l/min.

  11. Evaluation of actuators for the SDOF and MDOF active microgravity isolation systems

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The University of Virginia examined the design of actuators for both single-degree-of-freedom (SDOF) and multiple-degree-of-freedom (MDOF) active microgravity isolation systems. For SDOF systems, two actuators were considered: a special large gap magnetic actuator and a large stroke Lorentz actuator. The magnetic actuator was viewed to be of greater difficulty than the Lorentz actuator with little compelling technical advantage and was dropped from consideration. A Lorentz actuator was designed and built for the SDOF test rig using magnetic circuit and finite element analysis. The design and some experimental results are discussed. The University also examined the design of actuators for MDOF isolation systems. This includes design of an integrated 1 cm gap 6-DOF noncontacting magnetic suspension system and of a 'coarse' follower which permits the practical extension of magnetic suspension to large strokes. The proposed 'coarse' actuator was a closed kinematic chain manipulator known as a Stewart Platform. The integration of the two isolation systems together, the isolation tasks assigned to each, and possible control architectures were also explored. The results of this research are examined.

  12. Performance of an active control system with piezoelectric actuators

    NASA Technical Reports Server (NTRS)

    Baz, A.; Poh, S.

    1988-01-01

    Piezoelectric actuators are used to control the structural vibrations of flexible beams, and a modified independent modal space control method is employed to select the optimal location, control gains, and excitation voltage of the piezoelectric actuators. The method minimizes both the vibration amplitudes of the beams to which these actuators are bonded and the input control effort needed to suppress these vibrations. The effects of the actuators and the bonding layers on the elastic and inertial properties of the composite flexible beams is taken into account.

  13. Controllers for systems with bounded actuators: Scheduling and antiwindup

    NASA Astrophysics Data System (ADS)

    Sajjadi Kia, Solmaz

    The focus of this dissertation is one of the oldest, though in many ways unresolved, problems in control: actuator saturation. We start with an investigation of the effects of deferring the activation of anti-windup by allowing actuators to remain in the saturated regime longer, without any assistance. The basic idea is to apply anti-windup when the performance of the saturated system faces substantial degradation. For this, we present a modified anti-windup scheme along with the appropriate LMIs to obtain the gains in both cases of static and dynamic anti-windup. Benefits of the proposed design method over the immediate activation of the anti-windup are demonstrated through examples. Next, results are presented for developing a scheduling scheme for anti-windup compensators. The main idea is to devise a family of controllers that, when saturation is countered, can be used to override the nominal controller. At each instant, the active overriding controller is the most aggressive unsaturated member of the family. The emphasis is on providing performance guarantees, even for open loop unstable plants. The results include state feedback controllers and dynamic output feedback controllers with an order less than or equal to that of the plant. The benefits are demonstrated through some examples. Some of the design techniques proposed here are primarily multi-objective in nature, in which a controller is obtained that addresses more than one objective concurrently. Often, these problems lead to conservative results due to reliance on a common Lyapunov variable. To mitigate this conservatism, we develop a new variation of dilated matrix inequalities that are usually encountered in saturation problems. In these new dilated forms, the system matrices are separated from Lyapunov variable to allow the use of different Lyapunov matrices in multi-objective and robust problems. The results are applicable to both full state and full order dynamic output feedback synthesis

  14. Actuation and system design and evaluation OMS engine shutoff valve, Volume 1. [space shuttles

    NASA Technical Reports Server (NTRS)

    Dunn, V. B.

    1975-01-01

    A technology program was conducted to identify and verify the optimum valve and actuation system concept for the Space Shuttle Orbit Maneuvering System engine. Of major importance to the valve and actuation system selection was the ten-year, 100-mission, 10,000-cycle life requirement, while maintaining high reliability, low leakage, and low weight. Valve and actuation system concepts were comparatively evaluated against past valve failure reports and potential failure modes due to the shuttle mission profile to aid in the selection of the most optimum concept for design, manufacture and verification testing. Two valve concepts were considered during the preliminary design stage; i.e., the moving seat and lifting ball. Two actuation systems were manufactured and tested. Test results demonstrate the viability of a lifting ball concept as well as the applicability of an ac motor actuation system to best meet the requirements of the shuttle mission.

  15. Piezoelectric-hydraulic pump based band brake actuation system for automotive transmission control

    NASA Astrophysics Data System (ADS)

    Kim, Gi-Woo; Wang, K. W.

    2007-04-01

    The actuation system of friction elements (such as band brakes) is essential for high quality operations in modern automotive automatic transmissions (in short, ATs). The current band brake actuation system consists of several hydraulic components, including the oil pump, the regulating valve and the control valves. In general, it has been recognized that the current AT band brake actuation system has many limitations. For example, the oil pump and valve body are relatively heavy and complex. Also, the oil pumps induce inherently large drag torque, which affects fuel economy. This research is to overcome these problems of the current system by exploring the utilization of a hybrid type piezo-hydraulic pump device for AT band brake control. This new actuating system integrates a piezo-hydraulic pump to the input of the band brake. Compared with the current systems, this new actuator features much simpler structure, smaller size, and lower weight. This paper describes the development, design and fabrication of the new stand-alone prototype actuator for AT band brake control. An analytical model is developed and validated using experimental data. Performance tests on the hardware and system simulations utilizing the validated model are performed to characterize the new prototype actuator. It is predicted that with increasing of accumulator pressure and driving frequency, the proposed prototype actuating system will satisfy the band brake requirement for AT shift control.

  16. Transducer-actuator systems and methods for performing on-machine measurements and automatic part alignment

    DOEpatents

    Barkman, William E.; Dow, Thomas A.; Garrard, Kenneth P.; Marston, Zachary

    2016-07-12

    Systems and methods for performing on-machine measurements and automatic part alignment, including: a measurement component operable for determining the position of a part on a machine; and an actuation component operable for adjusting the position of the part by contacting the part with a predetermined force responsive to the determined position of the part. The measurement component consists of a transducer. The actuation component consists of a linear actuator. Optionally, the measurement component and the actuation component consist of a single linear actuator operable for contacting the part with a first lighter force for determining the position of the part and with a second harder force for adjusting the position of the part. The actuation component is utilized in a substantially horizontal configuration and the effects of gravitational drop of the part are accounted for in the force applied and the timing of the contact.

  17. Resonant micro and nanoelectromechanical systems: Actuation and biological sensing studies

    NASA Astrophysics Data System (ADS)

    Ilic, Bojan

    This thesis explores various actuation mechanisms of resonant nanoelectro-mechanical systems (NEMS) with emphasis directed towards detection of biomolecules. Arrays of bulk and surface micromachined devices, made using conventional thin film fabrication methods, are used to explore the mass loading effects of selective molecular immobilization on the surface of the NEMS resonators. Experimentally measured shift in the first eigenfrequency is correlated to the amount of mass loading from the binding events and verified using theoretical constructs. Under ambient conditions where considerable damping occurs, immunospecific detection of single Escherichia coli O157:H7 cells is demonstrated by measuring the out of plane vibrational resonant mode using an optical deflection system with thermal noise as an excitation mechanism. Further sensitivity enhancement utilizing vacuum encapsulation in conjunction with piezoelectric actuation and tailoring of the cantilever dimensions is demonstrated by measuring mass loading of a nonpathogenic insect baculovirus, single Aminopropyltriethoxysilane (APTS), Hexamethyldisilazane (HMDS) and Octade-cyltrichlorosilane (OTS) monolayers. To highlight the lower detectable mass limit, surface machined NEMS oscillators with integrated circular Au contacts and sub-attogram mass detection sensitivity are used for selective immobilization of dinitrophenyl poly(ethylene glycol) undecanthiol based molecules. Experimental and theoretical elucidation of optical actuation of NEMS cantilevers at large distances from the clamped end is presented. These observations are considered within the theoretical framework of heat transfer and used to measure binding events of single double-stranded deoxyribonucleic acid (dsDNA) molecules to localized gold nanodots near the free end of a NEMS oscillator. Because this method allows direct coupling of energy into the device layer, several modes of in-plane vibrations are observed and employed in shaking off

  18. Control system design for nano-positioning using piezoelectric actuators

    NASA Astrophysics Data System (ADS)

    Shan, Jinjun; Liu, Yanfang; Gabbert, Ulrich; Cui, Naigang

    2016-02-01

    This paper presents a systematic control system design for nano-positioning of a piezoelectric actuator (PEA). PEAs exhibit hysteresis nonlinearity, which can dramatically limit the application and performance of linear feedback control theory. Thus the hysteresis is compensated for based on the Maxwell resistive capacitor (MRC) model first. Then a proportional plus integral (PI) controller and a proportional double integral plus lead compensation (PII&L) controller are designed for the hysteresis-compensated PEA to account for model uncertainty, disturbance, and noise. The robust stability of both controllers is proved. The effectiveness of the proposed control scheme is demonstrated experimentally. Both controllers achieve fast precise positioning. The 2% settling times for the PI controller and the PII&L controller are 1.5 ms and 4.7 ms, respectively. The positioning resolution is upto 1 nm for both controllers.

  19. Topex high-gain antenna system deployment actuator mechanism

    NASA Technical Reports Server (NTRS)

    Jones, Stephen R.

    1991-01-01

    A deployment actuator mechanism was developed to drive a two-axis gimbal assembly and a high-gain antenna to a deployed and locked position on the Jet Propulsion Laboratory Ocean Topography Experiment (TOPEX) satellite. The Deployment Actuator Mechanism requirements, design, test, and associated problems and their solutions are discussed.

  20. Shape memory system with integrated actuation using embedded particles

    DOEpatents

    Buckley, Patrick R.; Maitland, Duncan J.

    2009-09-22

    A shape memory material with integrated actuation using embedded particles. One embodiment provides a shape memory material apparatus comprising a shape memory material body and magnetic pieces in the shape memory material body. Another embodiment provides a method of actuating a device to perform an activity on a subject comprising the steps of positioning a shape memory material body in a desired position with regard to the subject, the shape memory material body capable of being formed in a specific primary shape, reformed into a secondary stable shape, and controllably actuated to recover the specific primary shape; including pieces in the shape memory material body; and actuating the shape memory material body using the pieces causing the shape memory material body to be controllably actuated to recover the specific primary shape and perform the activity on the subject.

  1. Shape memory system with integrated actuation using embedded particles

    SciTech Connect

    Buckley, Patrick R; Maitland, Duncan J

    2014-04-01

    A shape memory material with integrated actuation using embedded particles. One embodiment provides a shape memory material apparatus comprising a shape memory material body and magnetic pieces in the shape memory material body. Another embodiment provides a method of actuating a device to perform an activity on a subject comprising the steps of positioning a shape memory material body in a desired position with regard to the subject, the shape memory material body capable of being formed in a specific primary shape, reformed into a secondary stable shape, and controllably actuated to recover the specific primary shape; including pieces in the shape memory material body; and actuating the shape memory material body using the pieces causing the shape memory material body to be controllably actuated to recover the specific primary shape and perform the activity on the subject.

  2. Shape memory system with integrated actuation using embedded particles

    DOEpatents

    Buckley, Patrick R.; Maitland, Duncan J.

    2012-05-29

    A shape memory material with integrated actuation using embedded particles. One embodiment provides a shape memory material apparatus comprising a shape memory material body and magnetic pieces in the shape memory material body. Another embodiment provides a method of actuating a device to perform an activity on a subject comprising the steps of positioning a shape memory material body in a desired position with regard to the subject, the shape memory material body capable of being formed in a specific primary shape, reformed into a secondary stable shape, and controllably actuated to recover the specific primary shape; including pieces in the shape memory material body; and actuating the shape memory material body using the pieces causing the shape memory material body to be controllably actuated to recover the specific primary shape and perform the activity on the subject.

  3. Analysis and design of delta operator systems with nested actuator saturation

    NASA Astrophysics Data System (ADS)

    Shi, Peng; Yang, Hongjiu; Zhang, Luyang

    2016-11-01

    In this paper, the problem of estimating the domain of attraction is considered for delta operator systems subject to nested actuator saturation. A set invariance condition is established for the delta operator system with nested actuator saturation in terms of auxiliary feedback matrices. Based on the set invariance condition, an optimisation approach is proposed to estimate the domain of attraction for the delta operator system. Thereby, the partial results of nested actuator saturation for both continuous-time systems and discrete-time systems are extended to delta operator system framework. A numerical example is provided to illustrate the effectiveness of the proposed design techniques.

  4. Direct Adaptive Control of Systems with Actuator Failures: State of the Art and Continuing Challenges

    NASA Technical Reports Server (NTRS)

    Tao, Gang; Joshi, Suresh M.

    2008-01-01

    In this paper, the problem of controlling systems with failures and faults is introduced, and an overview of recent work on direct adaptive control for compensation of uncertain actuator failures is presented. Actuator failures may be characterized by some unknown system inputs being stuck at some unknown (fixed or varying) values at unknown time instants, that cannot be influenced by the control signals. The key task of adaptive compensation is to design the control signals in such a manner that the remaining actuators can automatically and seamlessly take over for the failed ones, and achieve desired stability and asymptotic tracking. A certain degree of redundancy is necessary to accomplish failure compensation. The objective of adaptive control design is to effectively use the available actuation redundancy to handle failures without the knowledge of the failure patterns, parameters, and time of occurrence. This is a challenging problem because failures introduce large uncertainties in the dynamic structure of the system, in addition to parametric uncertainties and unknown disturbances. The paper addresses some theoretical issues in adaptive actuator failure compensation: actuator failure modeling, redundant actuation requirements, plant-model matching, error system dynamics, adaptation laws, and stability, tracking, and performance analysis. Adaptive control designs can be shown to effectively handle uncertain actuator failures without explicit failure detection. Some open technical challenges and research problems in this important research area are discussed.

  5. Advanced launch system (ALS) actuation and power systems impact operability and cost

    SciTech Connect

    Sundberg, G.R. . Lewis Research Center)

    1990-09-01

    To obtain the advanced launch system (ALS) primary goals of reduced costs ($300/lb earth to LEO) and improved operability, there must be significant reductions in the launch operability, there must be significant reductions in the launch operations and servicing requirements relative to current vehicle designs and practices. One of the primary methods for achieving these goals is by using electrical actuation integrated with a single vehicle electrical power system and controls for all actuation and avionics requirements. This paper reviews the ALS and its associated advanced development program to demonstrate maturation of those technologies that will help meet the overall operability and cost goals. The electric power and actuation systems are highlighted as a specific technology ready not only to meet the ALS goals (cryogenic fuel valves and thrust vector controls with peak power demands to 75 hp), but also those of other launch vehicles, military and civilian aircraft, lunar/Martian vehicles and a multitude of commercial applications.

  6. Control and network system of force actuators for deformable mirror active optics in LAMOST

    NASA Astrophysics Data System (ADS)

    Zhang, Shengtao; Zhang, Zhenchao; Wang, You

    2007-12-01

    The reflecting Schmidt plate M A of LAMOST consists of 24 segmented hexagonal sub-mirrors. Each sub-mirror is 25mm thick and 1.1m in diagonal. There are 34 force actuators on the back of one sub-mirror which need to be controlled to offer precise load to create correct mirror deformation. This paper presents the control method and network configuration of force actuators for one sub-mirror. Master computer running Windows NT operation system and slave controllers running DOS operation system are connected together via Ethernet local area network (ELAN) by means of TCP/IP protocol. Adopting five slave controllers, 34 force actuators are combined into a distributed system. Master computer controls five slave controllers and five slave controllers operate 34 force actuators. Master computer communicates with slave controllers normally, which receives state of each force actuator from slave controllers and sends instructions to slave controllers via Ethernet LAN. Each slave controller operates 8 force actuators to offer correct load. Axial load capacity of force actuator is +/-150N (pull and push) with accuracy RMS <=0.05N. Force sensor is used as close-loop feedback apparatus to detect the micro load of the actuator.

  7. Demonstration of Vibrational Braille Code Display Using Large Displacement Micro-Electro-Mechanical Systems Actuators

    NASA Astrophysics Data System (ADS)

    Watanabe, Junpei; Ishikawa, Hiroaki; Arouette, Xavier; Matsumoto, Yasuaki; Miki, Norihisa

    2012-06-01

    In this paper, we present a vibrational Braille code display with large-displacement micro-electro-mechanical systems (MEMS) actuator arrays. Tactile receptors are more sensitive to vibrational stimuli than to static ones. Therefore, when each cell of the Braille code vibrates at optimal frequencies, subjects can recognize the codes more efficiently. We fabricated a vibrational Braille code display that used actuators consisting of piezoelectric actuators and a hydraulic displacement amplification mechanism (HDAM) as cells. The HDAM that encapsulated incompressible liquids in microchambers with two flexible polymer membranes could amplify the displacement of the MEMS actuator. We investigated the voltage required for subjects to recognize Braille codes when each cell, i.e., the large-displacement MEMS actuator, vibrated at various frequencies. Lower voltages were required at vibration frequencies higher than 50 Hz than at vibration frequencies lower than 50 Hz, which verified that the proposed vibrational Braille code display is efficient by successfully exploiting the characteristics of human tactile receptors.

  8. Temporary physical protection systems

    SciTech Connect

    Williams, J.D.; Gangel, D.J.; Madsen, R.W. )

    1991-01-01

    Terrorism and other aspects of world political instability have created a high demand for temporary physical protection systems within the nuclear materials management community. They can be used when vehicles carrying important assets are away from their permanent fixed site location, around areas where experiments are being temporarily conducted, around construction areas and one portions of a fixed site physical security system which is temporarily inoperable. Physical security systems can be grouped into four categories: tactical, portable, semi-permanent, and fixed. The resources and experience gained at Sandia National Laboratories in over forty years of developing and implementing security systems for protecting nuclear weapons and fixed nuclear facilities is now being applied to temporary physical security systems. This paper emphasizes temporary physical security systems and their component parts that are presently available and identify additional system-subsystem objectives, requirements, and concepts.

  9. Conducting polymer actuators: From basic concepts to proprioceptive systems

    NASA Astrophysics Data System (ADS)

    Martinez Gil, Jose Gabriel

    Designers and engineers have been dreaming for decades of motors sensing, by themselves, working and surrounding conditions, as biological muscles do originating proprioception. Here bilayer full polymeric artificial muscles were checked up to very high cathodic potential limits (-2.5 V) in aqueous solution by cyclic voltammetry. The electrochemical driven exchange of ions from the conducting polymer film, and the concomitant Faradaic bending movement of the muscle, takes place in the full studied potential range. The presence of trapped counterion after deep reduction was corroborated by EDX determinations giving quite high electronic conductivity to the device. The large bending movement was used as a tool to quantify the amount of water exchanged per reaction unit (exchanged electron or ion). The potential evolutions of self-supported films of conducting polymers or conducting polymers (polypyrrole, polyaniline) coating different microfibers, during its oxidation/reduction senses working mechanical, thermal, chemical or electrical variables. The evolution of the muscle potential from electrochemical artificial muscles based on electroactive materials such as intrinsically conducting polymers and driven by constant currents senses, while working, any variation of the mechanical (trailed mass, obstacles, pressure, strain or stress), thermal or chemical conditions of work. One physically uniform artificial muscle includes one electrochemical motor and several sensors working simultaneously under the same driving reaction. Actuating (current and charge) and sensing (potential and energy) magnitudes are present, simultaneously, in the only two connecting wires and can be read by the computer at any time. From basic polymeric, mechanical and electrochemical principles a physicochemical equation describing artificial proprioception has been developed. It includes and describes, simultaneously, the evolution of the muscle potential during actuation as a function of the

  10. Thermally-actuated, phase change flow control for microfluidic systems.

    PubMed

    Chen, Zongyuan; Wang, Jing; Qian, Shizhi; Bau, Haim H

    2005-11-01

    An easy to implement, thermally-actuated, noninvasive method for flow control in microfluidic devices is described. This technique takes advantage of the phase change of the working liquid itself-the freezing and melting of a portion of a liquid slug-to noninvasively close and open flow passages (referred to as a phase change valve). The valve was designed for use in a miniature diagnostic system for detecting pathogens in oral fluids at the point of care. The paper describes the modeling, construction, and characteristics of the valve. The experimental results favorably agree with theoretical predictions. In addition, the paper demonstrates the use of the phase change valves for flow control, sample metering and distribution into multiple analysis paths, sealing of a polymerase chain reaction (PCR) chamber, and sample introduction into and withdrawal from a closed loop. The phase change valve is electronically addressable, does not require any moving parts, introduces only minimal dead volume, is leakage and contamination free, and is biocompatible.

  11. Advanced worker protection system

    SciTech Connect

    Caldwell, B.; Duncan, P.; Myers, J.

    1995-12-01

    The Department of Energy (DOE) is in the process of defining the magnitude and diversity of Decontamination and Decommissioning (D&D) obligations at its numerous sites. The DOE believes that existing technologies are inadequate to solve many challenging problems such as how to decontaminate structures and equipment cost effectively, what to do with materials and wastes generated, and how to adequately protect workers and the environment. Preliminary estimates show a tremendous need for effective use of resources over a relatively long period (over 30 years). Several technologies are being investigated which can potentially reduce D&D costs while providing appropriate protection to DOE workers. The DOE recognizes that traditional methods used by the EPA in hazardous waste site clean up activities are insufficient to provide the needed protection and worker productivity demanded by DOE D&D programs. As a consequence, new clothing and equipment which can adequately protect workers while providing increases in worker productivity are being sought for implementation at DOE sites. This project will result in the development of an Advanced Worker Protection System (AWPS). The AWPS will be built around a life support backpack that uses liquid air to provide cooling as well as breathing gas to the worker. The backpack will be combined with advanced protective garments, advanced liquid cooling garment, respirator, communications, and support equipment to provide improved worker protection, simplified system maintenance, and dramatically improve worker productivity through longer duration work cycles. Phase I of the project has resulted in a full scale prototype Advanced Worker Protection Ensemble (AWPE, everything the worker will wear), with sub-scale support equipment, suitable for integrated testing and preliminary evaluation. Phase II will culminate in a full scale, certified, pre-production AWPS and a site demonstration.

  12. Casimir and hydrodynamic force influence on microelectromechanical system actuation in ambient conditions

    NASA Astrophysics Data System (ADS)

    Sedighi, Mehdi; Palasantzas, George

    2014-02-01

    Casimir and hydrodynamic dissipation forces can strongly influence the actuation of microelectromechanical systems in ambient conditions. The dissipative and stiction dynamics of an actuating system is shown to depend on surface physical processes related to fluid slip and the size of the actuating components. Using phase change materials the Casimir force magnitude can be modulated via amorphous-crystalline phase transitions. The dissipative motion between amorphous coated phase change material components can be changed towards stiction upon crystallization and suitable choice of restoring spring constants. By contrast, amorphization can augment switching from stiction to dissipative dynamics.

  13. A new class of high force, low-voltage, compliant actuation system

    SciTech Connect

    RODGERS,M. STEVEN; KOTA,SRIDHAR; HETRICK,JOEL; LI,ZHE; JENSEN,BRIAN D.; KRYGOWSKI,THOMAS W.; MILLER,SAMUEL L.; BARNES,STEPHEN MATTHEW; BURG,MICHAEL STANLEY

    2000-04-10

    Although many actuators employing electrostatic comb drives have been demonstrated in a laboratory environment, widespread acceptance in mass produced microelectromechanical systems (MEMS) may be limited due to issues associated with low drive force, large real estate demands, high operating voltages, and reliability concerns due to stiction. On the other hand, comb drives require very low drive currents, offer predictable response, and are highly compatible with the fabrication technology. The expand the application space and facilitate the widespread deployment of self-actuated MEMS, a new class of advanced actuation systems has been developed that maintains the highly desirable aspects of existing components, while significantly diminishing the issues that could impede large scale acceptance. In this paper, the authors will present low-voltage electrostatic actuators that offer a dramatic increase in force over conventional comb drive designs. In addition, these actuators consume only a small fraction of the chip area previously used, yielding significant gains in power density. To increase the stroke length of these novel electrostatic actuators, the authors have developed highly efficient compliant stroke amplifiers. The coupling of compact, high-force actuators with fully compliant displacement multipliers sets a new paradigm for highly integrated microelectromechanical systems.

  14. Experimental Validation of the Piezoelectric Triple Hybrid Actuation System (TriHYBAS)

    NASA Technical Reports Server (NTRS)

    Xu, Tian-Bing; Jiang, Xiaoning; Su, Ji

    2008-01-01

    A piezoelectric triple hybrid actuation system (TriHYBAS) has been developed. In this brief presentation of the validation process the displacement profile of TriHYBAS and findings regarding displacement versus applied voltage are highlighted.

  15. Precision tracking control of dual-stage actuation system for optical manufacturing

    NASA Astrophysics Data System (ADS)

    Dong, W.; Tang, J.

    2009-03-01

    Actuators with high linear motion speed, high positioning resolution and long motion stroke are needed in many precision machining systems. In some current systems, voice coil motors (VCMs) are implemented for servo control. While the voice coil motors may provide long motion stroke needed in many applications, the main obstacle that hinders the improvement of the machining accuracy and efficiency is its limited bandwidth. To fundamentally solve this issue, we propose to develop a dual-stage actuation system that consists of a voice coil motor that covers the coarse motion and a piezoelectric stack actuator that induces the fine motion to enhance the positioning accuracy. A flexure hinge-based mechanism is developed to connect these two actuators together. A series of numerical and experimental studies are carried out to facilitate the system design and preliminary control development.

  16. Advanced worker protection system

    SciTech Connect

    Caldwell, B.; Duncan, P.; Myers, J.

    1995-10-01

    The Department of Energy (DOE) is in the process of defining the magnitude and diversity of Decontamination and Decommissioning (D&D) obligations at its numerous sites. The DOE believes that existing technologies are inadequate to solve many challenging problems such as how to decontaminate structures and equipment cost effectively, what to do with materials and wastes generated, and how to adequately protect workers and the environment. Preliminary estimates show a tremendous need for effective use of resources over a relatively long period (over 30 years). Several technologies are being investigated which can potentially reduce D&D costs while providing appropriate protection to DOE workers. The DOE recognizes that traditional methods used by the EPA in hazardous waste site clean up activities are insufficient to provide the needed protection and worker productivity demanded by DOE D&D programs. As a consequence, new clothing and equipment which can adequately protect workers while providing increases in worker productivity are being sought for implementation at DOE sites. This project describes the development of an Advanced Worker Protection System (AWPS) which will include a life-support backpack with liquid air for cooling and as a supply of breathing gas, protective clothing, respirators, communications, and support equipment.

  17. An electromechanical actuation system for an expendable launch vehicle

    NASA Technical Reports Server (NTRS)

    Burrows, Linda M.; Roth, Mary Ellen

    1992-01-01

    A major effort at the NASA Lewis Research Center in recent years has been to develop electro-mechanical actuators (EMA's) to replace the hydraulic systems used for thrust vector control (TVC) on launch vehicles. This is an attempt ot overcome the inherent inefficiencies and costs associated with the existing hydraulic structures. General Dynamics Space Systems Division, under contract to NASA Lewis, is developing 18.6 kW (25 hp), 29.8 kW (40 hp), and 52.2 kW (70 hp) peak EMA systems to meet the power demands for TVC on a family of vehicles developed for the National Launch System. These systems utilize a pulse population modulated converter and field-oriented control scheme to obtain independent control of both the voltage and frequency. These techniques allow an induction motor to be operated at its maximum torque at all times. At NASA Lewis, we are building on this technology to develop our own in-house system capable of meeting the peak power requirements for an expendable launch vehicle (ELV) such as the Atlas. Our EMA will be capable of delivering 22.4 kW (30 hp) peak power with a nominal of 6.0 kW (8 hp). This system differs from the previous ones in two areas: (1) the use of advanced control methods, and (2) the incorporation of built-in-test. The advanced controls are essential for minimizing the controller size, while the built-in-test is necessary to enhance the system reliability and vehicle health monitoring. The ultimate goal of this program is to demonstrate an EMA which will be capable of self-test and easy integration into other projects. This paper will describe the effort underway at NASA Lewis to develop an EMA for an Atlas class ELV. An explanation will be given for each major technology block, and the status of each major technology block and the status of the overall program will be reported.

  18. Performance of an Active Noise Control System for Fan Tones Using Vane Actuators

    NASA Technical Reports Server (NTRS)

    Sutliff, Daniel L.; Curtis, Alan R. D.; Heidelberg, Laurence J.; Remington, Paul J.

    2000-01-01

    An Active Noise Control (ANC) system for ducted fan noise was built that uses actuators located in stator vanes. The custom designed actuators A,ere piezoelectric benders manufactured using THUNDER technology. The ANC system was tested in the NASA Active Noise Control Fan rig. A total of 168 actuators in 28 stator vanes were used (six per vane). Simultaneous inlet and exhaust acoustic power level reductions were demonstrated for a fan modal structure that contained two radial modes in each direction. Total circumferential mode power levels were reduced by up to 9 dB in the inlet and 3 dB in the exhaust. The corresponding total 2BPF tone level reductions were by 6 dB in the inlet and 2 dB in the exhaust. Farfield sound pressure level reductions of up to 17 dB were achieved at the peak mode lobe angle. The performance of the system was limited by the constraints of the power amplifiers and the presence of control spillover. Simpler control/actuator systems using carefully selected subsets of the full system and random simulated failures of up to 7% of the actuators were investigated. (The actuators were robust and none failed during the test). Useful reductions still occurred under these conditions.

  19. Microprocessor controlled force actuator

    NASA Technical Reports Server (NTRS)

    Zimmerman, D. C.; Inman, D. J.; Horner, G. C.

    1986-01-01

    The mechanical and electrical design of a prototype force actuator for vibration control of large space structures (LSS) is described. The force actuator is an electromagnetic system that produces a force by reacting against a proof-mass. The actuator has two colocated sensors, a digital microcontroller, and a power amplifier. The total weight of actuator is .998 kg. The actuator has a steady state force output of approximately 2.75 N from approximately 2 Hz to well beyond 1000 Hz.

  20. Protective garment ventilation system

    NASA Technical Reports Server (NTRS)

    Lang, R. (Inventor)

    1970-01-01

    A method and apparatus for ventilating a protective garment, space suit system, and/or pressure suits to maintain a comfortable and nontoxic atmosphere within is described. The direction of flow of a ventilating and purging gas in portions of the garment may be reversed in order to compensate for changes in environment and activity of the wearer. The entire flow of the ventilating gas can also be directed first to the helmet associated with the garment.

  1. Advanced Launch System (ALS): Electrical actuation and power systems improve operability and cost picture

    NASA Technical Reports Server (NTRS)

    Sundberg, Gale R.

    1990-01-01

    To obtain the Advanced Launch System (ALS) primary goals of reduced costs and improved operability, there must be significant reductions in the launch operations and servicing requirements relative to current vehicle designs and practices. One of the primary methods for achieving these goals is by using vehicle electrical power system and controls for all actuation and avionics requirements. A brief status review of the ALS and its associated Advanced Development Program is presented to demonstrate maturation of those technologies that will help meet the overall operability and cost goals. The electric power and actuation systems are highlighted as a specific technology ready not only to meet the stringent ALS goals (cryogenic field valves and thrust vector controls with peak power demands to 75 hp), but also those of other launch vehicles, military and civilian aircraft, lunar/Martian vehicles, and a multitude of commercial applications.

  2. Advanced Launch System (ALS) actuation and power systems impact operability and cost

    NASA Technical Reports Server (NTRS)

    Sundberg, Gale R.

    1990-01-01

    To obtain the Advanced Launch System (ALS) primary goals of reduced costs and improved operability, there must be significant reductions in the launch operations and servicing requirements relative to current vehicle designs and practices. One of the primary methods for achieving these goals is by using vehicle electrical power system and controls for all actuation and avionics requirements. A brief status review of the ALS and its associated Advanced Development Program is presented to demonstrate maturation of those technologies that will help meet the overall operability and cost goals. The electric power and actuation systems are highlighted as a specific technology ready not only to meet the stringent ALS goals (cryogenic field valves and thrust vector controls with peak power demands to 75 hp), but also those of other launch vehicles, military and civilian aircraft, lunar/Martian vehicles, and a multitude of commercial applications.

  3. Tunable-focus liquid lens system controlled by antagonistic winding-type SMA actuator.

    PubMed

    Son, Hyung-Min; Kim, Min Young; Lee, Yun-Jung

    2009-08-01

    A new tunable-focus liquid lens system is proposed that consists of a liquid-filled PDMS (polydimethylsiloxane) membrane, special liquid injection mechanism based on a cam structure, antagonistic winding-type SMA(shape memory alloys) actuator for changing the surface curvature of the membrane, and liquid injection control system, including a digital signal processing board and actuator driver board. The focal length of the liquid lens is adjusted by changing the radius of the curvature of the liquid lens through redistributing the liquid using an injection mechanism. In the case of liquid lens systems using conventional injection mechanisms, the nonlinear relationship between the focal length change and the actuator displacement makes it difficult to control the focal length of the lens system, as there is only a narrow control range for adjusting the focal length over a wide range. In addition, miniaturization of the lens system is difficult due to the requirement of bulky and heavy actuators, such as an electrical motor and pump[7]. Thus, a relatively light and small SMA actuator is proposed for a compact lens system. This paper then provides a detailed description of the proposed tunable-focus liquid lens system, and an experimental system is also implemented. Finally, the focusing performance of the proposed liquid lens system is analyzed, and its usefulness and effectiveness verified through a series of experiments.

  4. Worcester 1 Inch Solenoid Actuated Gas Operated SCHe System Valves

    SciTech Connect

    MISKA, C.R.

    2000-09-03

    1 inch gas-operated full-port ball valves incorporate a solenoid and limit switches as integral parts of the actuator. These valves are normally open and fail safe to the open position (GOV-1*02 and 1*06 fail closed) to provide a flow path of helium gas to the MCO under helium purge and off-normal conditions when the MCO is isolated.

  5. Worcester 1 Inch Solenoid Actuated Gas Operated SCHe System Valves

    SciTech Connect

    VAN KATWIJK, C.

    2000-06-06

    1 inch Gas-operated full-port ball valves incorporate a solenoid and limit switches as integral parts of the actuator. These valves are normally open and fail safe to the open position (GOV-1*02 and 1*06 fail closed) to provide a flow path of helium gas to the MCO under helium purge and off-normal conditions when the MCO is isolated.

  6. Worcester 1 Inch Solenoid Actuated Gas Operated SCHe System Valves

    SciTech Connect

    MISKA, C.R.

    2000-11-13

    1 inch gas-operated full-port ball valves incorporate a solenoid and limit switches as integral parts of the actuator. These valves are normally open and fail safe to the open position (GOV-1*02 and 1*06 fail closed) to provide a flow path of helium gas to the MCO under helium purge and off-normal conditions when the MCO is isolated.

  7. Worcester 1 Inch Solenoid Actuated Gas Operated SCHe System Valves

    SciTech Connect

    VAN KATWIJK, C.

    2000-10-23

    1 inch Gas-operated full-port ball valves incorporate a solenoid and limit switches as integral parts of the actuator. These valves are normally open and fail safe to the open position (GOV-1*02 and 1*06 fall closed) to provide a flow path of helium gas to the MCO under helium purge and off-normal conditions when the MCO is isolated.

  8. Closed-loop control of a shape memory alloy actuation system for variable area fan nozzle

    NASA Astrophysics Data System (ADS)

    Barooah, Prabir; Rey, Nancy

    2002-07-01

    Shape Memory Alloys have been used in a wide variety of actuation applications. A bundled shape memory alloy cable actuator, capable of providing large force and displacement has been developed by United Technologies Corporation (patents pending) for actuating a Variable Area fan Nozzle (VAN). The ability to control fan nozzle exit area is an enabling technology for the next generation turbofan engines. Performance benefits for VAN engines are estimated to be up to 9% in Thrust Specific Fuel Consumption (TSFC) compared to traditional fixed geometry designs. The advantage of SMA actuated VAN design is light weight and low complexity compared to conventionally actuated designs. To achieve the maximum efficiency from a VAN engine, the nozzle exit area has to be continuously varied for a certain period of time during climb, since the optimum nozzle exit area is a function of several flight variables (flight Mach number, altitude etc). Hence, the actuator had to be controlled to provide the time varying desired nozzle area. A new control algorithm was developed for this purpose, which produced the desired flap area by metering the resistive heating of the SMA actuator. Since no active cooling was used, reducing overshoot was a significant challenge of the controller. A full scale, 2 flap model of the VAN system was built, which was capable of simulating a 20% nozzle area variation, and tested under full scale aerodynamic load in NASA Langley Jet Exit Test facility. The controller met all the requirements of the actuation system and was able to drive the flap position to the desired position with less than 2% overshoot in step input tests. The controller is based on a adaptive algorithm formulation with logical switches that reduces its overshoot error. Although the effectiveness of the controller was demonstrated in full scale model tests, no theoretical results as to its stability and robustness has been derived. Stability of the controller will have to be investigated

  9. Flexible system model reduction and control system design based upon actuator and sensor influence functions

    NASA Technical Reports Server (NTRS)

    Yam, Yeung; Johnson, Timothy L.; Lang, Jeffrey H.

    1987-01-01

    A model reduction technique based on aggregation with respect to sensor and actuator influence functions rather than modes is presented for large systems of coupled second-order differential equations. Perturbation expressions which can predict the effects of spillover on both the reduced-order plant model and the neglected plant model are derived. For the special case of collocated actuators and sensors, these expressions lead to the derivation of constraints on the controller gains that are, given the validity of the perturbation technique, sufficient to guarantee the stability of the closed-loop system. A case study demonstrates the derivation of stabilizing controllers based on the present technique. The use of control and observation synthesis in modifying the dimension of the reduced-order plant model is also discussed. A numerical example is provided for illustration.

  10. Strategic avionics technology definition studies. Subtask 3-1A: Electrical Actuation (ELA) systems

    NASA Technical Reports Server (NTRS)

    Pond, Charles L.; Mcdermott, William A.; Lum, Ben T. F.

    1993-01-01

    Electrical actuator (ELA) power efficiency and requirements are examined for space system application. Requirements for Space Shuttle effector systems are presented, along with preliminary ELA trades and selection to form a preliminary ELA system baseline. Power and energy requirements for this baseline ELA system are applicable to the Space Shuttle and similar space vehicles.

  11. Design of a linear-motion dual-stage actuation system for precision control

    NASA Astrophysics Data System (ADS)

    Dong, W.; Tang, J.; El Deeb, Y.

    2009-09-01

    Actuators with high linear-motion speed, high positioning resolution and a long motion stroke are needed in many precision machining systems. In some current systems, voice coil motors (VCMs) are implemented for servo control. While the voice coil motors may provide the long motion stroke needed in many applications, the main obstacle that hinders the improvement of the machining accuracy and efficiency is their limited bandwidth. To fundamentally solve this issue, we propose to develop a dual-stage actuation system that consists of a voice coil motor that covers the coarse motion, and a piezoelectric stack actuator that induces the fine motion, thus enhancing the positioning accuracy. The focus of this present research is the mechatronics design and synthesis of the new actuation system. In particular, a flexure hinge based mechanism is developed to provide a motion guide and preload to the piezoelectric stack actuator that is serially connected to the voice coil motor. This mechanism is built upon parallel plane flexure hinges. A series of numerical and experimental studies are carried out to facilitate the system design and the model identification. The effectiveness of the proposed system is demonstrated through open-loop studies and preliminary closed-loop control practice. While the primary goal of this particular design is aimed at enhancing optical lens machining, the concept and approach outlined are generic and can be extended to a variety of applications.

  12. Application of metal hydride paper to simple pressure generator for use in soft actuator systems.

    PubMed

    Ino, Shuichi; Sakaki, Kouji; Hosono, Minako; Doi, Kouki; Shimada, Shigenobu; Chikai, Manabu

    2015-01-01

    Metal hydride (MH) actuators have a simple structure and a number of features that make them attractive for use in rehabilitation engineering and assistive technology. The MH actuator provides a high power-to-weight ratio, high-strain actuation, human-compatible softness, and noiseless operation, while being environmentally benign. On the other hand, there remain technical challenges to be overcome to improve the MH actuator regarding its speed of operation and energy efficiency, given the low heat conductivity of the MH powder that is used as the pressure generator for soft actuation. To overcome the issues of low heat conductivity and the handling of MH powder, we developed an MH paper, which is a special paper incorporating MH powder and carbon fiber, for use as a new pressure-generating element for a soft MH actuator system. In addition, the basic properties and structure of the proposed MH paper were investigated through scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and several thermodynamic experiments. The results of these experiments showed that the hydrogen absorption and desorption rates of the MH paper were significantly higher than those of the MH powder around room temperature. PMID:26737365

  13. Application of metal hydride paper to simple pressure generator for use in soft actuator systems.

    PubMed

    Ino, Shuichi; Sakaki, Kouji; Hosono, Minako; Doi, Kouki; Shimada, Shigenobu; Chikai, Manabu

    2015-01-01

    Metal hydride (MH) actuators have a simple structure and a number of features that make them attractive for use in rehabilitation engineering and assistive technology. The MH actuator provides a high power-to-weight ratio, high-strain actuation, human-compatible softness, and noiseless operation, while being environmentally benign. On the other hand, there remain technical challenges to be overcome to improve the MH actuator regarding its speed of operation and energy efficiency, given the low heat conductivity of the MH powder that is used as the pressure generator for soft actuation. To overcome the issues of low heat conductivity and the handling of MH powder, we developed an MH paper, which is a special paper incorporating MH powder and carbon fiber, for use as a new pressure-generating element for a soft MH actuator system. In addition, the basic properties and structure of the proposed MH paper were investigated through scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and several thermodynamic experiments. The results of these experiments showed that the hydrogen absorption and desorption rates of the MH paper were significantly higher than those of the MH powder around room temperature.

  14. ADVANCED WORKER PROTECTION SYSTEM

    SciTech Connect

    Judson Hedgehock

    2001-03-16

    From 1993 to 2000, OSS worked under a cost share contract from the Department of Energy (DOE) to develop an Advanced Worker Protection System (AWPS). The AWPS is a protective ensemble that provides the user with both breathing air and cooling for a NIOSH-rated duration of two hours. The ensemble consists of a liquid air based backpack, a Liquid Cooling Garment (LCG), and an outer protective garment. The AWPS project was divided into two phases. During Phase 1, OSS developed and tested a full-scale prototype AWPS. The testing showed that workers using the AWPS could work twice as long as workers using a standard SCBA. The testing also provided performance data on the AWPS in different environments that was used during Phase 2 to optimize the design. During Phase 1, OSS also performed a life-cycle cost analysis on a representative clean up effort. The analysis indicated that the AWPS could save the DOE millions of dollars on D and D activities and improve the health and safety of their workers. During Phase 2, OSS worked to optimize the AWPS design to increase system reliability, to improve system performance and comfort, and to reduce the backpack weight and manufacturing costs. To support this design effort, OSS developed and tested several different generations of prototype units. Two separate successful evaluations of the ensemble were performed by the International Union of Operation Engineers (IUOE). The results of these evaluations were used to drive the design. During Phase 2, OSS also pursued certifying the AWPS with the applicable government agencies. The initial intent during Phase 2 was to finalize the design and then to certify the system. OSS and Scott Health and Safety Products teamed to optimize the AWPS design and then certify the system with the National Institute of Occupational Health and Safety (NIOSH). Unfortunately, technical and programmatic difficulties prevented us from obtaining NIOSH certification. Despite the inability of NIOSH to certify

  15. WASTE HANDLING BUILDING FIRE PROTECTION SYSTEM DESCRIPTION DOCUMENT

    SciTech Connect

    J. D. Bigbee

    2000-06-21

    The Waste Handling Building Fire Protection System provides the capability to detect, control, and extinguish fires and/or mitigate explosions throughout the Waste Handling Building (WHB). Fire protection includes appropriate water-based and non-water-based suppression, as appropriate, and includes the distribution and delivery systems for the fire suppression agents. The Waste Handling Building Fire Protection System includes fire or explosion detection panel(s) controlling various detectors, system actuation, annunciators, equipment controls, and signal outputs. The system interfaces with the Waste Handling Building System for mounting of fire protection equipment and components, location of fire suppression equipment, suppression agent runoff, and locating fire rated barriers. The system interfaces with the Waste Handling Building System for adequate drainage and removal capabilities of liquid runoff resulting from fire protection discharges. The system interfaces with the Waste Handling Building Electrical Distribution System for power to operate, and with the Site Fire Protection System for fire protection water supply to automatic sprinklers, standpipes, and hose stations. The system interfaces with the Site Fire Protection System for fire signal transmission outside the WHB as needed to respond to a fire emergency, and with the Waste Handling Building Ventilation System to detect smoke and fire in specific areas, to protect building high-efficiency particulate air (HEPA) filters, and to control portions of the Waste Handling Building Ventilation System for smoke management and manual override capability. The system interfaces with the Monitored Geologic Repository (MGR) Operations Monitoring and Control System for annunciation, and condition status.

  16. Subminiature hydraulic actuator

    NASA Technical Reports Server (NTRS)

    Sevart, F. D.

    1978-01-01

    Subminiature, single-vane rotary actuator for wind-tunnel test-model control-surface actuation systems presents severe torque and system band-pass requirements with stringent space and weight limitations. Actuator has very low leakage of fluid from one side to other, permitting use in precision position servo-systems.

  17. Ion-exchange polymer artificial muscle and actuating system

    NASA Astrophysics Data System (ADS)

    Vial, Dominique; Tondu, Bertrand; Lopez, Pierre; Aurelle, Yves; Ricard, Alain

    1996-04-01

    Chemomechanical transformations are used to produce a mechanical force from a reversible chemical reaction in order to generate artificial muscular contraction, on the model of the biological muscle. The design and experimentation of an original artificial muscle using an ion-exchange polymer which reacts inside a soft envelope, derived from research on pneumatic artificial McKibben muscle, is presented. Then a chemomechanical actuator constituted of two artificial muscles has been conceived: first results are shown on position control in open-loop mode.

  18. Dry actuation testing of viscous drag micropumping systems for determination of optimal drive waveforms

    NASA Astrophysics Data System (ADS)

    Sosnowchik, Brian D.; Galambos, Paul C.; Sharp, Kendra V.; Jenkins, Mark W.; Horn, Mark W.; Hendrix, Jason R.

    2003-12-01

    This paper presents the dry actuation testing procedures and results for novel viscous drag micropumping systems. To overcome the limitations of previously developed mechanical pumps, we have developed pumps that are surface micromachined for efficient mass production which utilize viscous drag (dominant at low Reynolds numbers typical of microfluidics) to move fluid. The SUMMiT (www.sandia.gov/micromachine) fabricated pumps, presented first by Kilani et al., are being experimentally and computationally analyzed. In this paper we will describe the development of optimal waveforms to drive the electrostatic pumping mechanism while dry. While wet actuation will be significantly different, dry testing provides insight into how to optimally move the mechanism and differences between dry and wet actuation can be used to isolate fluid effects. Characterization began with an analysis of the driving voltage waveforms for the torsional ratcheting actuator (TRA), a micro-motor that drove the gear transmission for the pump, actuated with SAMA (Sandia"s Arbitrary waveform MEMS Actuator), a new waveform generating computer program with the ability to generate and output arbitrary voltage signals. Based upon previous research, a 50% duty cycle half-sine wave was initially selected for actuation of the TRA. However, due to the geometry of the half-sine waveform, the loaded micromotor could not transmit the motion required to pump the tested liquids. Six waveforms were then conceived, constructed, and selected for device actuation testing. Dry actuation tests included high voltage, low voltage, high frequency, and endurance/reliability testing of the TRA, gear transmission and pump assembly. In the SUMMiT process, all of the components of the system are fabricated together on one silicon chip already assembled in a monolithic microfabrication process. A 40% duty cycle quarter-sine waveform with a 20% DC at 60V has currently proved to be the most reliable, allowing for an 825Hz

  19. Dry actuation testing of viscous drag micropumping systems for determination of optimal drive waveforms

    NASA Astrophysics Data System (ADS)

    Sosnowchik, Brian D.; Galambos, Paul C.; Sharp, Kendra V.; Jenkins, Mark W.; Horn, Mark W.; Hendrix, Jason R.

    2004-01-01

    This paper presents the dry actuation testing procedures and results for novel viscous drag micropumping systems. To overcome the limitations of previously developed mechanical pumps, we have developed pumps that are surface micromachined for efficient mass production which utilize viscous drag (dominant at low Reynolds numbers typical of microfluidics) to move fluid. The SUMMiT (www.sandia.gov/micromachine) fabricated pumps, presented first by Kilani et al., are being experimentally and computationally analyzed. In this paper we will describe the development of optimal waveforms to drive the electrostatic pumping mechanism while dry. While wet actuation will be significantly different, dry testing provides insight into how to optimally move the mechanism and differences between dry and wet actuation can be used to isolate fluid effects. Characterization began with an analysis of the driving voltage waveforms for the torsional ratcheting actuator (TRA), a micro-motor that drove the gear transmission for the pump, actuated with SAMA (Sandia"s Arbitrary waveform MEMS Actuator), a new waveform generating computer program with the ability to generate and output arbitrary voltage signals. Based upon previous research, a 50% duty cycle half-sine wave was initially selected for actuation of the TRA. However, due to the geometry of the half-sine waveform, the loaded micromotor could not transmit the motion required to pump the tested liquids. Six waveforms were then conceived, constructed, and selected for device actuation testing. Dry actuation tests included high voltage, low voltage, high frequency, and endurance/reliability testing of the TRA, gear transmission and pump assembly. In the SUMMiT process, all of the components of the system are fabricated together on one silicon chip already assembled in a monolithic microfabrication process. A 40% duty cycle quarter-sine waveform with a 20% DC at 60V has currently proved to be the most reliable, allowing for an 825Hz

  20. Systems approach to tamper protection

    SciTech Connect

    Myre, W. C.; Eaton, M. J.

    1980-01-01

    Tamper-protection is a fundamental requirement of effective containment and surveillance systems. Cost effective designs require that the tamper protection requirements be considered early in the design phase and at the system level. A discussion of tamper protection alternatives as well as an illustrative example system is presented.

  1. Operations manual for the data acquisition and reduction system, Area III Actuator Test Facility

    SciTech Connect

    Smith, E.L.

    1984-03-01

    This manual describes the operation of the new minicomputer-based data acquisition and reduction system for the Area III Actuator Test Facility at Sandia National Laboratories. The stand-alone digital system will alleviate current problems with test control and analysis and with data presentation. In its initial configuration, it will digitize test results recorded on FM tape and present the data graphically for reports. The ultimate goal of this system is to upgrade the performance, safety, and turnaround time of actuator tests through improved quality, analysis, and presentation of data.

  2. Actuator fault estimation and accommodation for switched systems with time delay: Discrete-time case.

    PubMed

    Du, Dongsheng; Jiang, Bin

    2016-05-01

    This paper investigates the problems of actuator fault estimation and accommodation for discrete-time switched systems with state delay. By using reduced-order observer method and switched Lyapunov function technique, a fault estimation algorithm is achieved for the discrete-time switched system with actuator fault and state delay. Then based on the obtained online fault estimation information, a switched dynamic output feedback controller is employed to compensate for the effect of faults by stabilizing the closed-loop systems. Finally, an example is proposed to illustrate the obtained results. PMID:26924247

  3. Actuator fault estimation and accommodation for switched systems with time delay: Discrete-time case.

    PubMed

    Du, Dongsheng; Jiang, Bin

    2016-05-01

    This paper investigates the problems of actuator fault estimation and accommodation for discrete-time switched systems with state delay. By using reduced-order observer method and switched Lyapunov function technique, a fault estimation algorithm is achieved for the discrete-time switched system with actuator fault and state delay. Then based on the obtained online fault estimation information, a switched dynamic output feedback controller is employed to compensate for the effect of faults by stabilizing the closed-loop systems. Finally, an example is proposed to illustrate the obtained results.

  4. Strategic avionics technology definition studies. Subtask 3-1A3: Electrical Actuation (ELA) Systems Test Facility

    NASA Technical Reports Server (NTRS)

    Rogers, J. P.; Cureton, K. L.; Olsen, J. R.

    1994-01-01

    Future aerospace vehicles will require use of the Electrical Actuator systems for flight control elements. This report presents a proposed ELA Test Facility for dynamic evaluation of high power linear Electrical Actuators with primary emphasis on Thrust Vector Control actuators. Details of the mechanical design, power and control systems, and data acquisition capability of the test facility are presented. A test procedure for evaluating the performance of the ELA Test Facility is also included.

  5. All inkjet-printed electroactive polymer actuators for microfluidic lab-on-chip systems

    NASA Astrophysics Data System (ADS)

    Pabst, Oliver; Beckert, Erik; Perelaer, Jolke; Schubert, Ulrich S.; Eberhardt, Ramona; Tünnermann, Andreas

    2013-04-01

    Piezoelectric electroactive polymers (EAP) are promising materials for applications in microfluidic lab-on-chip systems. In such systems, fluids can be analyzed by different chemical or physical methods. During the analysis the fluids need to be distributed through the channels of the chip, which requires a pumping function. We present here all inkjet-printed EAP actuators that can be configured as a membrane-based micropump suitable for direct integration into lab-on-chip systems. Drop-on-demand inkjet printing is a versatile digital deposition technique that is capable of depositing various functional materials onto a wide variety of substrates in an additive way. Compared to conventional lithography-based processing it is cost-efficient and flexible, as no masking is required. The actuators consist of a polymer foil substrate with an inkjet-printed EAP layer sandwiched between a set of two electrodes. The actuators are printed using a commercially available EAP solution and silver nanoparticle inks. When a voltage is applied across the polymer layer, piezoelectric strain leads to a bending deflection of the beam or membrane. Circular membrane actuators with 20 mm diameter and EAP thicknesses of 10 to 15 μm exhibit deflections of several μm when driven at their resonance frequency with voltages of 110 V. From the behavior of membrane actuators a pumping rate of several 100 μL/min can be estimated, which is promising for applications in lab-on-chip devices.

  6. Ferromagnetic shape memory flapper for remotely actuated propulsion systems

    NASA Astrophysics Data System (ADS)

    Kanner, Oren Y.; Shilo, Doron; Sheng, Jian; James, Richard D.; Ganor, Yaniv

    2013-08-01

    Generating propulsion with small-scale devices is a major challenge due to both the domination of viscous forces at low Reynolds numbers as well as the small relative stroke length of traditional actuators. Ferromagnetic shape memory materials are good candidates for such devices as they exhibit a unique combination of large strains and fast responses, and can be remotely activated by magnetic fields. This paper presents the design, analysis, and realization of a novel NiMnGa shear actuation method, which is especially suitable for small-scale fluid propulsion. A fluid mechanics analysis shows that the two key parameters for powerful propulsion are the engineering shear strain and twin boundary velocity. Using high-speed photography, we directly measure both parameters under an alternating magnetic field. Reynolds numbers in the inertial flow regime (>700) are evaluated. Measurements of the transient thrust show values up to 40 mN, significantly higher than biological equivalents. This work paves the way for new remotely activated and controlled propulsion for untethered micro-scale robots.

  7. Orbiter thermal protection system

    NASA Technical Reports Server (NTRS)

    Dotts, R. L.; Curry, D. M.; Tillian, D. J.

    1985-01-01

    The major material and design challenges associated with the orbiter thermal protection system (TPS), the various TPS materials that are used, the different design approaches associated with each of the materials, and the performance during the flight test program are described. The first five flights of the Orbiter Columbia and the initial flight of the Orbiter Challenger provided the data necessary to verify the TPS thermal performance, structural integrity, and reusability. The flight performance characteristics of each TPS material are discussed, based on postflight inspections and postflight interpretation of the flight instrumentation data. Flights to date indicate that the thermal and structural design requirements for the orbiter TPS are met and that the overall performance is outstanding.

  8. Distributed electromechanical actuation system design for a morphing trailing edge wing

    NASA Astrophysics Data System (ADS)

    Dimino, I.; Diodati, G.; Concilio, A.; Volovick, A.; Zivan, L.

    2016-04-01

    Next-generation flight control actuation technology will be based on "more electric" concepts to ensure benefits in terms of efficiency, weight and maintenance. This paper is concerned with the design of an un-shafted distributed servo-electromechanical actuation system, suited for morphing trailing edge wings of large commercial aircraft. It aims at producing small wing camber variations in the range between -5° and +5° in cruise, to enable aerodynamic efficiency improvements. The deployment kinematics is based on multiple "direct-drive" actuation, each made of light-weight compact lever mechanisms, rigidly connected to compliant ribs and sustained by load-bearing motors. Navier-Stokes computations are performed to estimate the pressure distribution over the interested wing region and the resulting hinge moments. These transfer to the primary structure via the driving mechanism. An electro-mechanical Matlab/Simulink model of the distributed actuation architecture is developed and used as a design tool, to preliminary evaluate the complete system performance. Implementing a multi-shaft strategy, each actuator is sized for the torque acting on the respective adaptive rib, following the effect of both the aerodynamic pressure and the morphing skin stiffness. Elastic trailing edge rotations and power needs are evaluated in operative conditions. Focus is finally given to the key challenges of the proposed concept: targeting quantifiable performance improvements while being compliant to the demanding requirements in terms of reliability and safety.

  9. Superconducting linear actuator

    NASA Technical Reports Server (NTRS)

    Johnson, Bruce; Hockney, Richard

    1993-01-01

    Special actuators are needed to control the orientation of large structures in space-based precision pointing systems. Electromagnetic actuators that presently exist are too large in size and their bandwidth is too low. Hydraulic fluid actuation also presents problems for many space-based applications. Hydraulic oil can escape in space and contaminate the environment around the spacecraft. A research study was performed that selected an electrically-powered linear actuator that can be used to control the orientation of a large pointed structure. This research surveyed available products, analyzed the capabilities of conventional linear actuators, and designed a first-cut candidate superconducting linear actuator. The study first examined theoretical capabilities of electrical actuators and determined their problems with respect to the application and then determined if any presently available actuators or any modifications to available actuator designs would meet the required performance. The best actuator was then selected based on available design, modified design, or new design for this application. The last task was to proceed with a conceptual design. No commercially-available linear actuator or modification capable of meeting the specifications was found. A conventional moving-coil dc linear actuator would meet the specification, but the back-iron for this actuator would weigh approximately 12,000 lbs. A superconducting field coil, however, eliminates the need for back iron, resulting in an actuator weight of approximately 1000 lbs.

  10. Influence of low optical frequencies on actuation dynamics of microelectromechanical systems via Casimir forces

    NASA Astrophysics Data System (ADS)

    Sedighi, Mehdi; Palasantzas, George

    2015-04-01

    The role of the Casimir force on the analysis of microactuators is strongly influenced by the optical properties of interacting materials. Bifurcation and phase portrait analysis were used to compare the sensitivity of actuators when the optical properties at low optical frequencies were modeled using the Drude and Plasma models. Indeed, for metallic systems, which have strong Casimir attraction, the details of the modeling of the low optical frequency regime can be dramatic, leading to predictions of either stable motion or stiction instability. However, this difference is strongly minimized for weakly conductive systems as are the doped insulators making actuation modeling more certain to predict.

  11. INTEGRATED DRILLING SYSTEM USING MUD ACTUATED DOWN HOLE HAMMER AS PRIMARY ENGINE

    SciTech Connect

    John V. Fernandez; David S. Pixton

    2005-12-01

    A history and project summary of the development of an integrated drilling system using a mud-actuated down-hole hammer as its primary engine are given. The summary includes laboratory test results, including atmospheric tests of component parts and simulated borehole tests of the hammer system. Several remaining technical hurdles are enumerated. A brief explanation of commercialization potential is included. The primary conclusion for this work is that a mud actuated hammer can yield substantial improvements to drilling rate in overbalanced, hard rock formations. A secondary conclusion is that the down-hole mud actuated hammer can serve to provide other useful down-hole functions including generation of high pressure mud jets, generation of seismic and sonic signals, and generation of diagnostic information based on hammer velocity profiles.

  12. Hydraulic engine valve actuation system including independent feedback control

    DOEpatents

    Marriott, Craig D

    2013-06-04

    A hydraulic valve actuation assembly may include a housing, a piston, a supply control valve, a closing control valve, and an opening control valve. The housing may define a first fluid chamber, a second fluid chamber, and a third fluid chamber. The piston may be axially secured to an engine valve and located within the first, second and third fluid chambers. The supply control valve may control a hydraulic fluid supply to the piston. The closing control valve may be located between the supply control valve and the second fluid chamber and may control fluid flow from the second fluid chamber to the supply control valve. The opening control valve may be located between the supply control valve and the second fluid chamber and may control fluid flow from the supply control valve to the second fluid chamber.

  13. Multi-Axis Independent Electromechanical Load Control for Docking System Actuation Development and Verification Using dSPACE

    NASA Technical Reports Server (NTRS)

    Oesch, Christopher; Dick, Brandon; Rupp, Timothy

    2015-01-01

    The development of highly complex and advanced actuation systems to meet customer demands has accelerated as the use of real-time testing technology expands into multiple markets at Moog. Systems developed for the autonomous docking of human rated spacecraft to the International Space Station (ISS), envelope multi-operational characteristics which place unique constraints on an actuation system. Real-time testing hardware has been used as a platform for incremental testing and development for the linear actuation system which controls initial capture and docking for vehicles visiting the ISS. This presentation will outline the role of dSPACE hardware as a platform for rapid control-algorithm prototyping as well as an Electromechanical Actuator (EMA) system dynamic loading simulator, both conducted at Moog to develop the safety critical Linear Actuator System (LAS) of the NASA Docking System (NDS).

  14. Actuating Fibers: Design and Applications.

    PubMed

    Stoychev, Georgi V; Ionov, Leonid

    2016-09-21

    Actuators are devices capable of moving or controlling objects and systems by applying mechanical force on them. Among all kinds of actuators with different shapes, fibrous ones deserve particular attention. In spite of their apparent simplicity, actuating fibers allow for very complex actuation behavior. This review discusses different approaches for the design of actuating fibers, and their advantages and disadvantages. We also discuss the prospects for the design of fibers with advanced architectures and complex actuation behavior. PMID:27571481

  15. Adaptive protection algorithm and system

    DOEpatents

    Hedrick, Paul [Pittsburgh, PA; Toms, Helen L [Irwin, PA; Miller, Roger M [Mars, PA

    2009-04-28

    An adaptive protection algorithm and system for protecting electrical distribution systems traces the flow of power through a distribution system, assigns a value (or rank) to each circuit breaker in the system and then determines the appropriate trip set points based on the assigned rank.

  16. Study of hydraulic actuation system for Space Shuttle main engine propellant valves

    NASA Technical Reports Server (NTRS)

    Ewel, Bob (Editor)

    1993-01-01

    Recent performance concerns involving the Space Shuttle Main Engine Propellant Valve Actuator assemblies prompted the NASA Marshall Space Flight Center to request an independent design assessment. Moog Inc. responded to this request and received a study contract with objectives of increasing valve reliability, decreasing maintenance costs while preserving the existing design interfaces. The results of the Propellant Valve Actuation System review focus on contamination control and the bypass valve design. Three proof of concept bypass valves employing design changes were built and successfully tested. Test results are presented.

  17. Failure of the Trailing Umbilical System Disconnect Actuator on the International Space Station

    NASA Technical Reports Server (NTRS)

    Gilmore, Adam; Schmitt, Chris; Merritt, Laura; Bolton, V. J.

    2008-01-01

    In December of 2005, one of two trailing umbilical cables used on the International Space Station (ISS) Mobile Transporter (MT) was inadvertently severed by an internal cutter system designed to free a snagged cable or jammed reel while transporting hazardous payloads. The mechanism s intended means of actuation is electrical; however, troubleshooting revealed a mechanical actuation occurred. The investigation of the failed component revealed several lessons learned in developing hardware requirements, understanding and following the rationale behind the requirements throughout the design life cycle, understanding the impacts of gaps and tolerances in a mechanism, and the importance of identifying critical steps during assembly.

  18. Failure of the Trailing Umbilical System Disconnect Actuator on the International Space Station

    NASA Technical Reports Server (NTRS)

    Gilmore, Adam; Schmitt, Chris; Merritt, Laura; Bolton, V. J.

    2008-01-01

    In December of 2005, one of two trailing umbilical cables used on the International Space Station (ISS) Mobile Transporter (MT) was inadvertently severed by an internal cutter system designed to free a snagged cable or jammed reel while transporting hazardous payloads. The mechanism s intended means of actuation is electrical; however, troubleshooting revealed a mechanical actuation occurred. The investigation of the failed component revealed several lessons learned in developing hardware requirements, understanding and following the rationale behind the requirements throughout the design life cycle, understanding the impacts of gaps and tolerances in a mechanism, and the importance of identifying critical steps during assembly

  19. Application of a passive/active autoparametric cantilever beam absorber with PZT actuator for Duffing systems

    NASA Astrophysics Data System (ADS)

    Silva-Navarro, G.; Abundis-Fong, H. F.; Vazquez-Gonzalez, B.

    2013-04-01

    An experimental investigation is carried out on a cantilever-type passive/active autoparametric vibration absorber, with a PZT patch actuator, to be used in a primary damped Duffing system. The primary system consists of a mass, viscous damping and a cubic stiffness provided by a soft helical spring, over which is mounted a cantilever beam with a PZT patch actuator actively controlled to attenuate harmonic and resonant excitation forces. With the PZT actuator on the cantilever beam absorber, cemented to the base of the beam, the auto-parametric vibration absorber is made active, thus enabling the possibility to control the effective stiffness and damping associated to the passive absorber and, as a consequence, the implementation of an active vibration control scheme able to preserve, as possible, the autoparametric interaction as well as to compensate varying excitation frequencies and parametric uncertainty. This active vibration absorber employs feedback information from a high resolution optical encoder on the primary Duffing system and an accelerometer on the tip beam absorber, a strain gage on the base of the beam, feedforward information from the excitation force and on-line computations from the nonlinear approximate frequency response, parameterized in terms of a proportional gain provided by a voltage input to the PZT actuator, thus modifying the closed-loop dynamic stiffness and providing a mechanism to asymptotically track an optimal, robust and stable attenuation solution on the primary Duffing system. Experimental results are included to describe the dynamic and robust performance of the overall closed-loop system.

  20. Quiet Clean Short-haul Experimental Engine (QCSEE) whirl test of cam/harmonic pitch change actuation system

    NASA Technical Reports Server (NTRS)

    1976-01-01

    A variable pitch fan actuation system, which incorporates a remote nacelle mounted blade angle regulator, was tested. The regulator drives a rotating fan mounted mechanical actuator through a flexible shaft and differential gear train. The actuator incorporates a high ratio harmonic drive attached to a multitrack spherical cam which changes blade pitch through individual cam follower arms attached to each blade trunnion. Testing of the actuator on a whirl rig, is reported. Results of tests conducted to verify that the unit satisfied the design requirements and was structurally adequate for use in an engine test are presented.

  1. Personal Radiation Protection System

    NASA Technical Reports Server (NTRS)

    McDonald, Mark; Vinci, Victoria

    2004-01-01

    A report describes the personal radiation protection system (PRPS), which has been invented for use on the International Space Station and other spacecraft. The PRPS comprises walls that can be erected inside spacecraft, where and when needed, to reduce the amount of radiation to which personnel are exposed. The basic structural modules of the PRPS are pairs of 1-in. (2.54-cm)-thick plates of high-density polyethylene equipped with fasteners. The plates of each module are assembled with a lap joint. The modules are denoted bricks because they are designed to be stacked with overlaps, in a manner reminiscent of bricks, to build 2-in. (5.08-cm)-thick walls of various lengths and widths. The bricks are of two varieties: one for flat wall areas and one for corners. The corner bricks are specialized adaptations of the flat-area bricks that make it possible to join walls perpendicular to each other. Bricks are attached to spacecraft structures and to each other by use of straps that can be tightened to increase the strengths and stiffnesses of joints.

  2. AMSD Cryo Actuator Testing

    NASA Technical Reports Server (NTRS)

    Mullette, Mark; Matthews, Gary; Russell, Kevin (Technical Monitor)

    2002-01-01

    The actuator technology required for AMSD and subsequently NGST are critical in the successful development for future cryogenic systems. Kodak has undertaken an extensive test plan to determine the performance of the force actuators developed under the AMSD program. These actuators are currently in testing at MSFC and are expected to finish this test cycle in early June 2002.

  3. Low spring index, large displacement Shape Memory Alloy (SMA) coil actuators for use in macro- and micro-systems

    NASA Astrophysics Data System (ADS)

    Holschuh, Brad; Newman, Dava

    2014-03-01

    Shape memory alloys (SMA) offer unique shape changing characteristics that can be exploited to produce low­ mass, low-bulk, large-stroke actuators. We are investigating the use of low spring index (defined as the ratio of coil diameter to wire diameter) SMA coils for use as actuators in morphing aerospace systems. Specifically, we describe the development and characterization of minimum achievable spring index coiled actuators made from 0.3048 mm (0.012") diameter shape memory alloy (SMA) wire for integration in textile architectures for future compression space suit applications. Production and shape setting of the coiled actuators, as well as experimental test methods, are described. Force, length and voltage relationships for multiple coil actuators are reported and discussed. The actuators exhibit a highly linear (R2 < 0.99) relationship between isometric blocking force and coil displacement, which is consistent with current SMA coil models; and SMA coil actuators demonstrate the ability to produce significant linear forces (i.e., greater than 8 N per coil) at strains up to 3x their initial (i.e., fully coiled) length. Discussions of both the potential use of these actuators in future compression space suit designs, and the broader viability of these actuators in both macro- and micro-systems, are presented.

  4. Fiber Optic Experience with the Smart Actuation System on the F-18 Systems Research Aircraft

    NASA Technical Reports Server (NTRS)

    Zavala, Eddie

    1997-01-01

    High bandwidth, immunity to electromagnetic interference, and potential weight savings have led to the development of fiber optic technology for future aerospace vehicle systems. This technology has been incorporated in a new smart actuator as the primary communication interface. The use of fiber optics simplified system integration and significantly reduced wire count. Flight test results showed that fiber optics could be used in aircraft systems and identified critical areas of development of fly-by-light technology. This paper documents the fiber optic experience gained as a result of this program, and identifies general design considerations that could be used in a variety of specific applications of fiber optic technology. Environmental sensitivities of fiber optic system components that significantly contribute to optical power variation are discussed. Although a calibration procedure successfully minimized the effect of fiber optic sensitivities, more standardized calibration methods are needed to ensure system operation and reliability in future aerospace vehicle systems.

  5. Development of a magneto-rheological fluid based hybrid actuation system

    NASA Astrophysics Data System (ADS)

    John, Shaju

    A hybrid hydraulic actuation system is proposed as an active pitch link for rotorcraft applications. Such an active pitch link can be used to implement Individual Blade Control (IBC) techniques for vibration and noise reduction, in addition to providing primary control for the helicopter. Conventional technologies like electric motors and hydraulic actuators have major disadvantages when it come to applications on a rotating environment. Centralized hydraulic system require the use of mechanically complex hydraulic slip rings and electric motors have high precision mechanical moving parts that make them unattractive in application with high centrifugal load. The high energy density of smart materials can be used to design hydraulic actuators in a compact package. MagnetoRheological (MR) fluids can be used as the working fluid in such a hybrid hydraulic actuation system to implement a valving system with no moving parts. Thus, such an actuation system can be theoretically well-suited for application in a rotating environment. To develop an actuation system based on an active material stack and MR fluidic valves, a fundamental understanding of the hydraulic circuit is essential. In order to address this issue, a theoretical model was developed to understand the effect of pumping chamber geometry on the pressure losses in the pumping chamber. Three dimensional analytical models were developed for steady and unsteady flow and the results were correlated to results obtained from Computation Fluid Dynamic simulation of fluid flow inside the pumping chamber. Fundamental understanding regarding the pressure losses in a pumping chamber are obtained from the modeling process. Vortices that form in the pumping chamber (during intake) and the discharge tube (during discharge) are identified as a major cause of pressure loss in the chamber. The role of vortices during dynamic operation is also captured through a frequency domain model. Extensive experimental studies were

  6. 30 CFR 250.1611 - Blowout preventer systems tests, actuations, inspections, and maintenance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... conducting high-pressure tests, all BOP systems shall be tested to a pressure of 200 to 300 psi. (b) Ram-type... pipe-ram test pressures. Safety valves with proper casing connections shall be actuated prior to... equipment. The weekly pressure test is not required for blind and blind-shear rams; (4) Bind and...

  7. Control of systems with tiered actuators with application to interferometer optical delay line control

    NASA Technical Reports Server (NTRS)

    Lurie, Boris J.; Hadaegh, Fred Y.

    2004-01-01

    High accuracy feedback control systems might employ tiers of actuators with different properties. Such systems performance can be estimated in advance using Bode integrals. The systems can be made globally stable with good transient responses and close to the best possible disturbance rejection when controllers include high-order linear links and multiple nonlinear dynamic links. The design approach is exemplified by designing conb-ol system for an interferometer optical delay line.

  8. A Method for Exploiting Redundancy to Accommodate Actuator Limits in Multivariable Systems

    NASA Technical Reports Server (NTRS)

    Litt, Jonathan; Roulette, Greg

    1995-01-01

    This paper introduces a new method for accommodating actuator saturation in a multivariable system with actuator redundancy. Actuator saturation can cause significant deterioration in control system performance because unmet demand may result in sluggish transients and oscillations in response to setpoint changes. To help compensate for this problem, a technique has been developed which takes advantage of redundancy in multivariable systems to redistribute the unmet control demand over the remaining useful effectors. This method is not a redesign procedure, rather it modifies commands to the unlimited effectors to compensate for those which are limited, thereby exploiting the built-in redundancy. The original commands are modified by the increments due to unmet demand, but when a saturated effector comes off its limit, the incremental commands disappear and the original unmodified controller remains intact. This scheme provides a smooth transition between saturated and unsaturated modes as it divides up the unmet requirement over any available actuators. This way, if there is sufficiently redundant control authority, performance can be maintained.

  9. A smart experimental technique for the optimization of dielectric elastomer actuator (DEA) systems

    NASA Astrophysics Data System (ADS)

    Hodgins, M.; Rizzello, G.; York, A.; Naso, D.; Seelecke, S.

    2015-09-01

    In order to aid in moving dielectric elastomer actuator (DEA) technology from the laboratory into a commercial product DEA prototypes should be tested against a variety of loading conditions and eventually in the end user conditions. An experimental test setup to seamlessly perform mechanical characterization and loading of the DEA would be a great asset toward this end. Therefore, this work presents the design, control and systematic validation of a benchtop testing station for miniature silicon based circular DEAs. A versatile benchtop tester is able to characterize and apply programmable loading forces to the DEA while measuring actuator performance. The tester successfully applied mechanical loads to the DEA (including positive, constant and negative stiffness loads) simulating biasing systems via an electromagnetic linear motor operating in closed loop with a force/mechanical impedance control scheme. The tester expedites mechanical testing of the DEA by eliminating the need to build intricate pre-load mechanisms or use multiple testing jigs for characterizing the DEA response. The results show that proper mechanical loading of the DEA increases the overall electromechanical sensitivity of the system and thereby the actuator output. This approach to characterize and apply variable loading forces to DEAs in a single test system will enable faster realization of higher performance actuators.

  10. Modeling of plant protection and control systems for SSC

    SciTech Connect

    Khatib-Rahbar, M.

    1980-06-01

    Plant protection and feedback control systems for dynamic simulation of liquid-metal-cooled fast breeder reactors are developed. The models include manual and automatic shutdown systems with provision for selective suppression of PPS signals. The control system models include (1) supervisory control, (2) the reactor power control and rod drive mechanism, (3) primary and intermediate flow-speed control and pump drive system, and (4) steam generator flow-speed control and valve/pump actuator dynamics. These models have been incorporated into the SSC code using a flexible programming approach, in order to accommodate some design dependent variations. 11 figs., 2 tabs.

  11. The X-43 Fin Actuation System Problem - Reliability in Shades of Gray

    NASA Technical Reports Server (NTRS)

    Peebles, Curtis

    2006-01-01

    Following the loss of the first X-43 during launch, the mishap investigation board indicated the Fin Actuator System (FAS) needed to have a larger torque margin. To supply this added torque, a second actuator was added. The consequences of what seemed to be a simple modification would trouble the X-43 program. Because of the second actuator, a new computer board was required. This proved to be subject to electronic noise. This resulted in the actuator latch up in ground tests of the FAS for the second launch. Such a latch up would cause the Pegasus booster to fail, as the FAS was a single string system. The problem was corrected and the second flight was successful. The same modifications were added to the FAS for flight three. When the FAS underwent ground tests, it also latched up. The failure indicated that each computer board had a different tolerance to electronic noise. The problem with the FAS was corrected. Subsequently, another failure occurred, raising questions about the design, and the probability of failure for the X-43 Mach 10 flight. This was not simply a technical issue, but illuminated the difficulties facing both managers and engineers in assessing risk, design requirements, and probabilities in cutting edge aerospace projects.

  12. Magnetorheological valve based actuator for improvement of passively controlled turbocharger system

    NASA Astrophysics Data System (ADS)

    Bahiuddin, I.; Mazlan, S. A.; Imaduddin, F.; Ubaidillah, Ichwan, B.

    2016-03-01

    Variable geometry turbochargers have been widely researched to fulfil the current engine stringent regulations. The passively controlled turbocharger (PCT) concept has been proposed to reduce energy consumption by utilizing the emission energy to move the actuator. However, it only covered a small range operating condition. Therefore, a magnetorheological(MR) Valve device, as typical smart material devices to enhance a passive device, is proposed to improve the PCT. Even though the benefits have been considered for the compactness and easiness to connect to an electrical system, the number of publications regarding the MR application within engine system is hard to be found. Therefore, this paper introduces a design of an MR Valve in a turbocharger. The main challenge is to make sure its capability to produce a sufficient total pressure drop. To overcome the challenge, its material properties, shape and pressure drop calculation has been analyzed to fulfil the requirement. Finally, to get a more understanding of actuator performance, the actuator response was simulated by treating the exhaust gas pressure as an input. It shows that the new MR actuator has a potential dynamic to improve the PCT controllability.

  13. A reinforcement discrete neuro-adaptive control for unknown piezoelectric actuator systems with dominant hysteresis.

    PubMed

    Hwang, Chih-Lyang; Jan, Chau

    2003-01-01

    The theoretical and experimental studies of a reinforcement discrete neuro-adaptive control for unknown piezoelectric actuator systems with dominant hysteresis are presented. Two separate nonlinear gains, together with an unknown linear dynamical system, construct the nonlinear model (NM) of the piezoelectric actuator systems. A nonlinear inverse control (NIC) according to the learned NM is then designed to compensate the hysteretic phenomenon and to track the reference input without the risk of discontinuous response. Because the uncertainties are dynamic, a recurrent neural network (RNN) with residue compensation is employed to model them in a compact subset. Then, a discrete neuro-adaptive sliding-mode control (DNASMC) is designed to enhance the system performance. The stability of the overall system is verified by Lyapunov stability theory. Comparative experiments for various control schemes are also given to confirm the validity of the proposed control.

  14. Advanced launch system (ALS) - Electrical actuation and power systems improve operability and cost picture

    NASA Technical Reports Server (NTRS)

    Sundberg, Gale R.

    1990-01-01

    To obtain the Advanced Launch System (ALS) primary goals of reduced costs and improved operability, there must be significant reductions in the launch operations and servicing requirements relative to current vehicle designs and practices. One of the primary methods for achieving these goals is by using vehicle electrrical power system and controls for all aviation and avionics requirements. A brief status review of the ALS and its associated Advanced Development Program is presented to demonstrate maturation of those technologies that will help meet the overall operability and cost goals. The electric power and actuation systems are highlighted as a sdpecific technology ready not only to meet the stringent ALS goals (cryogenic field valves and thrust vector controls with peak power demands to 75 hp), but also those of other launch vehicles, military ans civilian aircraft, lunar/Martian vehicles, and a multitude of comercial applications.

  15. Data-based fault-tolerant control for affine nonlinear systems with actuator faults.

    PubMed

    Xie, Chun-Hua; Yang, Guang-Hong

    2016-09-01

    This paper investigates the fault-tolerant control (FTC) problem for unknown nonlinear systems with actuator faults including stuck, outage, bias and loss of effectiveness. The upper bounds of stuck faults, bias faults and loss of effectiveness faults are unknown. A new data-based FTC scheme is proposed. It consists of the online estimations of the bounds and a state-dependent function. The estimations are adjusted online to compensate automatically the actuator faults. The state-dependent function solved by using real system data helps to stabilize the system. Furthermore, all signals in the resulting closed-loop system are uniformly bounded and the states converge asymptotically to zero. Compared with the existing results, the proposed approach is data-based. Finally, two simulation examples are provided to show the effectiveness of the proposed approach. PMID:27180025

  16. Self-Learning Variable Structure Control for a Class of Sensor-Actuator Systems

    PubMed Central

    Chen, Sanfeng; Li, Shuai; Liu, Bo; Lou, Yuesheng; Liang, Yongsheng

    2012-01-01

    Variable structure strategy is widely used for the control of sensor-actuator systems modeled by Euler-Lagrange equations. However, accurate knowledge on the model structure and model parameters are often required for the control design. In this paper, we consider model-free variable structure control of a class of sensor-actuator systems, where only the online input and output of the system are available while the mathematic model of the system is unknown. The problem is formulated from an optimal control perspective and the implicit form of the control law are analytically obtained by using the principle of optimality. The control law and the optimal cost function are explicitly solved iteratively. Simulations demonstrate the effectiveness and the efficiency of the proposed method. PMID:22778633

  17. Sensor-integrated polymer actuators for closed-loop drug delivery system

    NASA Astrophysics Data System (ADS)

    Xu, Han; Wang, Chunlei; Kulinsky, Lawrence; Zoval, Jim; Madou, Marc

    2006-03-01

    This work presents manufacturing and testing of a closed-loop drug delivery system where drug release is achieved by an electrochemical actuation of an array of polymeric valves on a set of drug reservoirs. The valves are based on bi-layer structures made of polypyrrole/gold in the shape of a flap that is hinged on one side of a valve seat. Drugs stored in the underlying chambers are released by bending the bi-layer flaps back with a small applied bias. These polymeric valves simultaneously function as both drug release components and biological/chemical sensors responding to a specific biological or environmental stimulus. The sensors may send signals to the control module to realize closed-loop control of the drug release. In this study a glucose sensor has been integrated with the polymeric actuators through immobilization of glucose oxidase(GOx) within polypyrrole(PPy) valves. Sensitivities per unit area of the integrated glucose sensor have been measured and compared before and after the actuation of the sensor/actuator PPy/DBS/GOx film. Other sensing parameters such as linear range and response time were discussed as well. Using an array of these sensor/actuator cells, the amount of released drug, e.g. insulin, can be precisely controlled according to the surrounding glucose concentration detected by the glucose sensor. Activation of these reservoirs can be triggered either by the signal from the sensor, or by the signal from the operator. This approach also serves as the initial step to use the proposed system as an implantable drug delivery platform in the future.

  18. Design and performance evaluation of a new jetting dispenser system using two piezostack actuators

    NASA Astrophysics Data System (ADS)

    Jeon, Juncheol; Hong, Seung-Min; Choi, Minkyu; Choi, Seung-Bok

    2015-01-01

    This paper presents a new jetting dispenser system which is adaptable to various packaging processes such as light emitting diode packaging and flip chip packaging. The proposed dispenser system is driven by piezostack actuators and a lever-hinge mechanism. In order to improve jetting performances such as accurate dispensed amount and adaptability to high viscosity fluid, two piezostack actuators are used. By activating the two actuators dually, the angular displacement of the lever can be controlled to produce a required motion of the needle. Firstly, the configuration and working principles of the proposed jetting system are explained, the design of the dispenser is then conducted and significant geometric dimensions of the dispenser are presented. In the design process, several operational requirements such as the maximum needle stroke, operational frequency, and amplification ratio of the lever-hinge are considered. The principal design parameters of the jetting dispenser system are determined from static and modal analysis using the finite element analysis. After obtaining the dimensional characteristics, the control logic for the dispensing operation is explained using a feed-forward controller. The piezostack-driven jetting dispenser system and control devices are then fabricated to evaluate the dispenser performance. It is shown experimentally that by changing the input voltage conditions, the amount of fluid dispensed by the proposed jetting system can be effectively controlled to achieve the desired jetting performance.

  19. UIO design for singular delayed LPV systems with application to actuator fault detection and isolation

    NASA Astrophysics Data System (ADS)

    Hassanabadi, Amir Hossein; Shafiee, Masoud; Puig, Vicenc

    2016-01-01

    In this paper, the unknown input observer (UIO) design for singular delayed linear parameter varying (LPV) systems is considered regarding its application to actuator fault detection and isolation. The design procedure assumes that the LPV system is represented in the polytopic framework. Existence and convergence conditions for the UIO are established. The design procedure is formulated by means of linear matrix inequalities (LMIs). Actuator fault detection and isolation is based on using the UIO approach for designing a residual generator that is completely decoupled from unknown inputs and exclusively sensitive to faults. Fault isolation is addressed considering two different strategies: dedicated and generalised bank of observers' schemes. The applicability of these two schemes for the fault isolation is discussed. An open flow canal system is considered as a case study to illustrate the performance and usefulness of the proposed fault detection and isolation method in different fault scenarios.

  20. A new type of a direct-drive valve system driven by a piezostack actuator and sliding spool

    NASA Astrophysics Data System (ADS)

    Jeon, Juncheol; Han, Chulhee; Han, Young-Min; Choi, Seung-Bok

    2014-07-01

    A direct-drive valve (DDV) system is a kind of electrohydraulic servo valve system, in which the actuator directly drives the spool of the valve. In conventional DDV systems, the spool is generally driven by an electromagnetic actuator. Performance characteristics such as frequency bandwidth of DDV systems driven by the electromagnetic actuator are limited due to the actuator response property. In order to improve the performance characteristics of conventional DDV systems, in this work a new configuration for a direct-drive valve system actuated by a piezostack actuator with a flexible beam mechanism is proposed (in short, a piezo-driven DDV system). Its benefits are demonstrated through both simulation and experiment. After describing the geometric configuration and operational principle of the proposed valve system, a governing equation of the whole system is obtained by combining the dynamic equations of the fluid part and the structural parts: the piezostack, the flexible beam, and the spool. In the structural parts of the piezostack and flexible beam, a lumped parameter modeling method is used, while the conventional rule of the fluid momentum is used for the fluid part. In order to evaluate valve performances of the proposed system, an experimental apparatus consisting of a hydraulic circuit and the piezo-driven DDV system is established. The performance characteristics are evaluated in terms of maximum spool displacement, flow rate, frequency characteristics, and step response. In addition, in order to advocate the feasibility of the proposed dynamic model, a comparison between simulation and experiment is undertaken.

  1. An Analytic Model for the Success Rate of a Robotic Actuator System in Hitting Random Targets.

    PubMed

    Bradley, Stuart

    2015-11-20

    Autonomous robotic systems are increasingly being used in a wide range of applications such as precision agriculture, medicine, and the military. These systems have common features which often includes an action by an "actuator" interacting with a target. While simulations and measurements exist for the success rate of hitting targets by some systems, there is a dearth of analytic models which can give insight into, and guidance on optimization, of new robotic systems. The present paper develops a simple model for estimation of the success rate for hitting random targets from a moving platform. The model has two main dimensionless parameters: the ratio of actuator spacing to target diameter; and the ratio of platform distance moved (between actuator "firings") to the target diameter. It is found that regions of parameter space having specified high success are described by simple equations, providing guidance on design. The role of a "cost function" is introduced which, when minimized, provides optimization of design, operating, and risk mitigation costs.

  2. Helicopter force-feel and stability augmentation system with parallel servo-actuator

    NASA Technical Reports Server (NTRS)

    Hoh, Roger H. (Inventor)

    2006-01-01

    A force-feel system is implemented by mechanically coupling a servo-actuator to and in parallel with a flight control system. The servo-actuator consists of an electric motor, a gearing device, and a clutch. A commanded cockpit-flight-controller position is achieved by pilot actuation of a trim-switch. The position of the cockpit-flight-controller is compared with the commanded position to form a first error which is processed by a shaping function to correlate the first error with a commanded force at the cockpit-flight-controller. The commanded force on the cockpit-flight-controller provides centering forces and improved control feel for the pilot. In an embodiment, the force-feel system is used as the basic element of stability augmentation system (SAS). The SAS provides a stabilization signal that is compared with the commanded position to form a second error signal. The first error is summed with the second error for processing by the shaping function.

  3. Adaptive control for a class of MIMO nonlinear time delay systems against time varying actuator failures.

    PubMed

    Hashemi, Mahnaz; Ghaisari, Jafar; Askari, Javad

    2015-07-01

    This paper investigates an adaptive controller for a class of Multi Input Multi Output (MIMO) nonlinear systems with unknown parameters, bounded time delays and in the presence of unknown time varying actuator failures. The type of considered actuator failure is one in which some inputs may be stuck at some time varying values where the values, times and patterns of the failures are unknown. The proposed approach is constructed based on a backstepping design method. The boundedness of all the closed-loop signals is guaranteed and the tracking errors are proved to converge to a small neighborhood of the origin. The proposed approach is employed for a double inverted pendulums benchmark and a chemical reactor system. The simulation results show the effectiveness of the proposed method.

  4. System and method for controlling engine knock using electro-hydraulic valve actuation

    DOEpatents

    Brennan, Daniel G

    2013-12-10

    A control system for an engine includes a knock control module and a valve control module. The knock control module adjusts a period that one or more of an intake valve and an exhaust valve of a cylinder are open based on engine knock corresponding to the cylinder. The valve control module, based on the adjusted period, controls the one or more of the intake valve and the exhaust valve using one or more hydraulic actuators.

  5. Feasibility of an anticipatory noncontact precrash restraint actuation system

    SciTech Connect

    Kercel, S.W.; Dress, W.B.

    1995-12-31

    The problem of providing an electronic warning of an impending crash to a precrash restraint system a fraction of a second before physical contact differs from more widely explored problems, such as providing several seconds of crash warning to a driver. One approach to precrash restraint sensing is to apply anticipatory system theory. This consists of nested simplified models of the system to be controlled and of the system`s environment. It requires sensory information to describe the ``current state`` of the system and the environment. The models use the sensory data to make a faster-than-real-time prediction about the near future. Anticipation theory is well founded but rarely used. A major problem is to extract real-time current-state information from inexpensive sensors. Providing current-state information to the nested models is the weakest element of the system. Therefore, sensors and real-time processing of sensor signals command the most attention in an assessment of system feasibility. This paper describes problem definition, potential ``showstoppers,`` and ways to overcome them. It includes experiments showing that inexpensive radar is a practical sensing element. It considers fast and inexpensive algorithms to extract information from sensor data.

  6. Modeling and Simulation of Control Actuation System with Fuzzy-PID Logic Controlled Brushless Motor Drives for Missiles Glider Applications

    PubMed Central

    Muniraj, Murali; Arulmozhiyal, Ramaswamy

    2015-01-01

    A control actuation system has been used extensively in automotive, aerospace, and defense applications. The major challenges in modeling control actuation system are rise time, maximum peak to peak overshoot, and response to nonlinear system with percentage error. This paper addresses the challenges in modeling and real time implementation of control actuation system for missiles glider applications. As an alternative fuzzy-PID controller is proposed in BLDC motor drive followed by linkage mechanism to actuate fins in missiles and gliders. The proposed system will realize better rise time and less overshoot while operating in extreme nonlinear dynamic system conditions. A mathematical model of BLDC motor is derived in state space form. The complete control actuation system is modeled in MATLAB/Simulink environment and verified by performing simulation studies. A real time prototype of the control actuation is developed with dSPACE-1104 hardware controller and a detailed analysis is carried out to confirm the viability of the proposed system. PMID:26613102

  7. Modeling and Simulation of Control Actuation System with Fuzzy-PID Logic Controlled Brushless Motor Drives for Missiles Glider Applications.

    PubMed

    Muniraj, Murali; Arulmozhiyal, Ramaswamy

    2015-01-01

    A control actuation system has been used extensively in automotive, aerospace, and defense applications. The major challenges in modeling control actuation system are rise time, maximum peak to peak overshoot, and response to nonlinear system with percentage error. This paper addresses the challenges in modeling and real time implementation of control actuation system for missiles glider applications. As an alternative fuzzy-PID controller is proposed in BLDC motor drive followed by linkage mechanism to actuate fins in missiles and gliders. The proposed system will realize better rise time and less overshoot while operating in extreme nonlinear dynamic system conditions. A mathematical model of BLDC motor is derived in state space form. The complete control actuation system is modeled in MATLAB/Simulink environment and verified by performing simulation studies. A real time prototype of the control actuation is developed with dSPACE-1104 hardware controller and a detailed analysis is carried out to confirm the viability of the proposed system. PMID:26613102

  8. Analysis and design for delta operator systems with actuator saturation

    NASA Astrophysics Data System (ADS)

    Yang, Hongjiu; Shi, Peng; Li, Zhiwei; Hua, Changchun

    2014-05-01

    This paper studies the problem of estimating the domain of attraction for delta operator systems under a pre-designed saturated linear feedback. Ellipsoids are used as the estimates of domain of attraction for delta operator systems. A condition is derived in terms of an auxiliary feedback matrix for determining if a given ellipsoid is contractive invariant. Moreover, some necessary and sufficient conditions are given for single input delta operator systems. The results are also further extended to determine the invariant sets for delta operator systems with persistent disturbances. Linear matrix inequalities based on the methods are developed for constructing feedback laws that achieve disturbance rejection with guaranteed stability requirements. Some numerical examples are given to illustrate the effectiveness of the developed techniques.

  9. Large space structure model reduction and control system design based upon actuator and sensor influence functions

    NASA Technical Reports Server (NTRS)

    Yam, Y.; Lang, J. H.; Johnson, T. L.; Shih, S.; Staelin, D. H.

    1983-01-01

    A model reduction procedure based on aggregation with respect to sensor and actuator influences rather than modes is presented for large systems of coupled second-order differential equations. Perturbation expressions which can predict the effects of spillover on both the aggregated and residual states are derived. These expressions lead to the development of control system design constraints which are sufficient to guarantee, to within the validity of the perturbations, that the residual states are not destabilized by control systems designed from the reduced model. A numerical example is provided to illustrate the application of the aggregation and control system design method.

  10. Strategic avionics technology definition studies. Subtask 3-1A: Electrical Actuation (ELA) systems

    NASA Technical Reports Server (NTRS)

    Lum, Ben T. F.; Pond, Charles; Dermott, William

    1993-01-01

    This interim report presents the preliminary results of an electrical actuation (ELA) system study (subtask TA3-1A) to support the NASA strategic avionics technology definition studies. The final report of this ELA study is scheduled for September 30, 1993. The topics are presented in viewgraph form and include the following ELA technology demonstration testing; ELA system baseline; power and energy requirements for shuttle effector systems; power efficiency and losses of ELA effector systems; and power and energy requirements for ELA power sources.

  11. Control of the unilluminated deformable mirror actuators in an altitude-conjugated adaptive optics system

    PubMed

    Veran

    2000-07-01

    Off-axis observations made with adaptive optics are severely limited by anisoplanatism errors. However, conjugating the deformable mirror to an optimal altitude can reduce these errors; it is then necessary to control, through extrapolation, actuators that are not measured by the wave-front sensor (unilluminated actuators). In this study various common extrapolation schemes are investigated, and an optimal method that achieves a significantly better performance is proposed. This extrapolation method involves a simple matrix multiplication and will be implemented in ALTAIR, the Gemini North Telescope adaptive optics system located on Mauna Kea, Hawaii. With this optimal method, the relative H-band Strehl reduction due to extrapolation errors is only 5%, 16%, and 30% when the angular distance between the guide source and the science target is 20, 40 and 60 arc sec, respectively. For a site such as Mauna Kea, these errors are largely outweighed by the increase in the size of the isoplanatic field.

  12. Control of the unilluminated deformable mirror actuators in an altitude-conjugated adaptive optics system

    PubMed

    Veran

    2000-07-01

    Off-axis observations made with adaptive optics are severely limited by anisoplanatism errors. However, conjugating the deformable mirror to an optimal altitude can reduce these errors; it is then necessary to control, through extrapolation, actuators that are not measured by the wave-front sensor (unilluminated actuators). In this study various common extrapolation schemes are investigated, and an optimal method that achieves a significantly better performance is proposed. This extrapolation method involves a simple matrix multiplication and will be implemented in ALTAIR, the Gemini North Telescope adaptive optics system located on Mauna Kea, Hawaii. With this optimal method, the relative H-band Strehl reduction due to extrapolation errors is only 5%, 16%, and 30% when the angular distance between the guide source and the science target is 20, 40 and 60 arc sec, respectively. For a site such as Mauna Kea, these errors are largely outweighed by the increase in the size of the isoplanatic field. PMID:10883986

  13. Hydraulically actuated fuel injector including a pilot operated spool valve assembly and hydraulic system using same

    DOEpatents

    Shafer, Scott F.

    2002-01-01

    The present invention relates to hydraulic systems including hydraulically actuated fuel injectors that have a pilot operated spool valve assembly. One class of hydraulically actuated fuel injectors includes a solenoid driven pilot valve that controls the initiation of the injection event. However, during cold start conditions, hydraulic fluid, typically engine lubricating oil, is particularly viscous and is often difficult to displace through the relatively small drain path that is defined past the pilot valve member. Because the spool valve typically responds slower than expected during cold start due to the difficulty in displacing the relatively viscous oil, accurate start of injection timing can be difficult to achieve. There also exists a greater difficulty in reaching the higher end of the cold operating speed range. Therefore, the present invention utilizes a fluid evacuation valve to aid in displacement of the relatively viscous oil during cold start conditions.

  14. An adaptive brain actuated system for augmenting rehabilitation

    PubMed Central

    Roset, Scott A.; Gant, Katie; Prasad, Abhishek; Sanchez, Justin C.

    2014-01-01

    For people living with paralysis, restoration of hand function remains the top priority because it leads to independence and improvement in quality of life. In approaches to restore hand and arm function, a goal is to better engage voluntary control and counteract maladaptive brain reorganization that results from non-use. Standard rehabilitation augmented with developments from the study of brain-computer interfaces could provide a combined therapy approach for motor cortex rehabilitation and to alleviate motor impairments. In this paper, an adaptive brain-computer interface system intended for application to control a functional electrical stimulation (FES) device is developed as an experimental test bed for augmenting rehabilitation with a brain-computer interface. The system's performance is improved throughout rehabilitation by passive user feedback and reinforcement learning. By continuously adapting to the user's brain activity, similar adaptive systems could be used to support clinical brain-computer interface neurorehabilitation over multiple days. PMID:25565945

  15. Radio frequency telemetry system for sensors and actuators

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N. (Inventor); Miranda, Felix A. (Inventor)

    2003-01-01

    The present invention discloses and teaches apparatus for combining Radio Frequency (RF) technology with novel micro-inductor antennas and signal processing circuits for RF telemetry of real time, measured data, from microelectromechanical system (MEMS) sensors, through electromagnetic coupling with a remote powering/receiving device. Such technology has many applications, but is especially useful in the biomedical area.

  16. Radio Frequency Telemetry System for Sensors and Actuators

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N. (Inventor); Miranda, Felix A. (Inventor)

    2003-01-01

    The present invention discloses and teaches apparatus for combining Radio Frequency (RF) technology with novel micro-inductor antennas and signal processing circuits for RF telemetry of real time, measured data, from microelectromechanical system (MEMS) sensors, through electromagnetic coupling with a remote poweringheceiving device. Such technology has many applications, but is especially useful in the biomedical area.

  17. Structural integrated sensor and actuator systems for active flow control

    NASA Astrophysics Data System (ADS)

    Behr, Christian; Schwerter, Martin; Leester-Schädel, Monika; Wierach, Peter; Dietzel, Andreas; Sinapius, Michael

    2016-04-01

    An adaptive flow separation control system is designed and implemented as an essential part of a novel high-lift device for future aircraft. The system consists of MEMS pressure sensors to determine the flow conditions and adaptive lips to regulate the mass flow and the velocity of a wall near stream over the internally blown Coanda flap. By the oscillating lip the mass flow in the blowing slot changes dynamically, consequently the momentum exchange of the boundary layer over a high lift flap required mass flow can be reduced. These new compact and highly integrated systems provide a real-time monitoring and manipulation of the flow conditions. In this context the integration of pressure sensors into flow sensing airfoils of composite material is investigated. Mechanical and electrical properties of the integrated sensors are investigated under mechanical loads during tensile tests. The sensors contain a reference pressure chamber isolated to the ambient by a deformable membrane with integrated piezoresistors connected as a Wheatstone bridge, which outputs voltage signals depending on the ambient pressure. The composite material in which the sensors are embedded consists of 22 individual layers of unidirectional glass fiber reinforced plastic (GFRP) prepreg. The results of the experiments are used for adapting the design of the sensors and the layout of the laminate to ensure an optimized flux of force in highly loaded structures primarily for future aeronautical applications. It can be shown that the pressure sensor withstands the embedding process into fiber composites with full functional capability and predictable behavior under stress.

  18. Self-actuating heat switches for redundant refrigeration systems

    NASA Technical Reports Server (NTRS)

    Chan, Chung K. (Inventor)

    1988-01-01

    A dual refrigeration system for cooling a sink device is described, which automatically thermally couples the cold refrigerator to the sink device while thermally isolating the warm refrigerator from the sink device. The system includes two gas gap heat switches that each thermally couples one of the refrigerators to the sink device, and a pair of sorption pumps that are coupled through tubes to the heat switches. When the first refrigerator is operated and therefore cold, the first pump which is thermally coupled to it is also cooled and adsorbs gas to withdraw it from the second heat switch, to thereby thermally isolate the sink device from the warm second refrigerator. With the second refrigerator being warm, the second pump is also warm and desorbs gas, so the gas lies in the first switch, to close that switch and therefore thermally couple the cold first refrigerator to the sink device. Thus, the heat switches are automatically switched according to the temperature of the corresponding refrigerator.

  19. Magnetically-Actuated Escherichia coli System for Micro Lithography

    NASA Astrophysics Data System (ADS)

    Lauback, S.; Brown, E.; Pérez-Guzman, L.; Peace, C.; Pierce, C.; Lower, B. H.; Lower, S. K.; Sooryakumar, R.

    2015-03-01

    Technologies that control matter at the nano- and micro-scale are crucial for developing new engineered materials and devices. While the more traditional approaches for such manipulations often depend on lithographic fabrication, they can be expanded upon by taking advantage of the biological systems within a living cell which also operate on the nano- and micro- scale. In this study, a system is being developed to functionalize a targeted location on the surface of a chip with the protein AmCyan from transformed Escherichia coli cells. Using established methods in molecular biology where a plasmid with the amcyan gene sequence is inserted into the cell, E. coli are engineered to express the AmCyan protein on their outer surface. In order to transport the cells to the targeted location, the transformed E. coli are labeled with superparamagnetic micro-beads which exert directed forces on the cells in an external field. Preliminary results of the protein expression on E. coli, the transport of the cell through weak magnetic fields to targeted locations and the potential to transfer protein from the cell to the chip surface will be presented.

  20. A Portable, Air-Jet-Actuator-Based Device for System Identification

    NASA Astrophysics Data System (ADS)

    Staats, Wayne; Belden, Jesse; Mazumdar, Anirban; Hunter, Ian

    2010-11-01

    System identification (ID) of human and robotic limbs could help in diagnosis of ailments and aid in optimization of control parameters and future redesigns. We present a self-contained actuator, which uses the Coanda effect to rapidly switch the direction of a high speed air jet to create a binary stochastic force input to a limb for system ID. The design of the actuator is approached with the goal of creating a portable device, which could deployed on robot or human limbs for in situ identification. The viability of the device is demonstrated by performing stochastic system ID on an underdamped elastic beam system with fixed inertia and stiffness, and variable damping. The non-parametric impulse response yielded from the stochastic system ID is modeled as a second order system, and the resultant parameters are found to be in excellent agreement with those found using more traditional system ID techniques. The current design could be further miniaturized and developed as a portable, wireless, on-site multi-axis system identification system for less intrusive and more widespread use.

  1. Electropneumatic actuator, phase 1

    NASA Astrophysics Data System (ADS)

    Bloomfield, D. P.

    1989-10-01

    The program demonstrated the feasibility of an electropneumatic actuator which can be used in manufacturing applications. The electropneumatic actuator, an alternative to the electric, hydraulic, and pneumatic actuators used in industry, consists of an electrochemical compressor, a power supply, and an actuator. The electrochemical compressor working fluid is hydrogen and a solvent such as water or ammonia. The compressor has no moving parts and runs on low voltage DC. The actuator is a conventional, commercially available unit. Researchers designed, constructed, and tested the electrochemical compressor in conjunction with the actuator, power supply, and computerized control. The one inch actuator can lift a fifty pound weight a distance of ten inches in about 1.5 minutes. The electrochemically powered system is capable of driving its loaded actuator to a prescribed location at a controlled rate. A defined set of design changes will combine the compressor and actuator in the same housing, and will develop two orders of magnitude increased actuator speed at the same or higher force levels.

  2. Thermo-actuated migration in a micro-system

    NASA Astrophysics Data System (ADS)

    Jullien, Marie-Caroline; Selva, Bertrand; Cantat, Isabelle

    2012-02-01

    Digital microfluidics require element displacement by simple means featuring high integration rates. Within this context, the transport and handling of elements constitutes a problem [Squires and Quake, 2005]. This context has rekindled interest in the Marangoni surface effect, which refers to tangential stresses along an interface. Producing a surface tension gradient by imposing a temperature gradient is especially efficient and easy to control. In a recent paper, we have shown [Selva et al., Phys. Fluids (2011)] that a bubble undergoing a constant temperature gradient is indeed set into motion. However, the direction of motion (toward the cooler side) is in contradiction with experiments performed at the millimetre scale in which bubble migration is driven towards hoter regions. We believe this observation is due to the PDMS deformability. Indeed, PDMS expands when the temperature increases. A temperature gradient inside a microsystem results in a cavity thickness gradient, and thus leads to the bubble travelling towards the thicker part of the cavity. The physical phenomena involved in such a system are multifaceted (PDMS dilation, thermocapillarity, solutocapillarity) and may have either complementary or opposite effects depending on the experimental conditions.

  3. Design and control of dual servo actuator for near field optical recording system

    NASA Astrophysics Data System (ADS)

    Jeong, Jaehwa; Choi, Young-Man; Lee, Jun-Hee; Yoon, Hyoung-Kil; Gweon, Dae-Gab

    2005-12-01

    Near field recording (NFR) has been introduced as a new optical data storage method to realize higher data density beyond the diffraction limit. As the data density increases, the track pitch is remarkably reduced to about 400nm. Thus, more precise actuator is required and we propose a dual servo actuator to improve the accuracy of actuator. The proposed dual servo actuator consists of a coarse actuator and a fine actuator, multisegmented magnet array (MSMA) voice coil motor (VCM) and PMN-PT actuator. In design of VCM actuator, a novel magnetic circuit of VCM with MSMA is proposed. It can generate higher air gap flux density than the magnetic circuit of VCM with the conventional magnet array. In design of fine actuator, the fine actuator including PMN-PT single crystal instead of the conventional PZT is proposed. The displacement gain of PMN-PT fine actuator is 26 nm/V and that of PZT fine actuator is 17 nm/V. The displacement gain is increased by 53 %. To evaluate tracking performance of the manufactured dual servo actuator and to assign the proper role to each actuator, the PQ method is selected. From experiment results, the total bandwidth of the dual servo actuator is increased to 2.5kHz and the resolution is 25 nm. Comparing with the resolution of one servo actuator, 70 nm, we can find that the accuracy of actuator is remarkably improved. And the proposed dual servo actuator shows satisfactory performances to be applied to NFR and it can be applied to other future disk drives.

  4. State and actuator fault estimation observer design integrated in a riderless bicycle stabilization system.

    PubMed

    Brizuela Mendoza, Jorge Aurelio; Astorga Zaragoza, Carlos Manuel; Zavala Río, Arturo; Pattalochi, Leo; Canales Abarca, Francisco

    2016-03-01

    This paper deals with an observer design for Linear Parameter Varying (LPV) systems with high-order time-varying parameter dependency. The proposed design, considered as the main contribution of this paper, corresponds to an observer for the estimation of the actuator fault and the system state, considering measurement noise at the system outputs. The observer gains are computed by considering the extension of linear systems theory to polynomial LPV systems, in such a way that the observer reaches the characteristics of LPV systems. As a result, the actuator fault estimation is ready to be used in a Fault Tolerant Control scheme, where the estimated state with reduced noise should be used to generate the control law. The effectiveness of the proposed methodology has been tested using a riderless bicycle model with dependency on the translational velocity v, where the control objective corresponds to the system stabilization towards the upright position despite the variation of v along the closed-loop system trajectories. PMID:26708303

  5. State and actuator fault estimation observer design integrated in a riderless bicycle stabilization system.

    PubMed

    Brizuela Mendoza, Jorge Aurelio; Astorga Zaragoza, Carlos Manuel; Zavala Río, Arturo; Pattalochi, Leo; Canales Abarca, Francisco

    2016-03-01

    This paper deals with an observer design for Linear Parameter Varying (LPV) systems with high-order time-varying parameter dependency. The proposed design, considered as the main contribution of this paper, corresponds to an observer for the estimation of the actuator fault and the system state, considering measurement noise at the system outputs. The observer gains are computed by considering the extension of linear systems theory to polynomial LPV systems, in such a way that the observer reaches the characteristics of LPV systems. As a result, the actuator fault estimation is ready to be used in a Fault Tolerant Control scheme, where the estimated state with reduced noise should be used to generate the control law. The effectiveness of the proposed methodology has been tested using a riderless bicycle model with dependency on the translational velocity v, where the control objective corresponds to the system stabilization towards the upright position despite the variation of v along the closed-loop system trajectories.

  6. Static feedback stabilization of nonlinear systems with single sensor and single actuator.

    PubMed

    Wang, Jiqiang; Hu, Zhongzhi; Ye, Zhifeng

    2014-01-01

    This paper considers a single sensor and single actuator approach to the static feedback stabilization of nonlinear systems. This is essentially a remote control problem that is present in many engineering applications. The proposed method solves this problem that is less expensive to implement and more reliable in practice. Significant results are obtained on the design of controllers for stabilizing the nonlinear systems. Important issues on control implementation are also discussed. The proposed design method is validated through its application to nonlinear control of aircraft engines.

  7. Robust stabilisation and L2 -gain analysis for switched systems with actuator saturation under asynchronous switching

    NASA Astrophysics Data System (ADS)

    Wang, Juan; Zhao, Jun

    2016-09-01

    Robust stabilisation and L2-gain analysis for a class of switched systems with actuator saturation are studied in this paper. The switching signal of the controllers lags behind that of the system modes, which leads to the asynchronous switching between the candidate controllers and the subsystems. By combining the piecewise Lyapunov function method with the convex hull technique, sufficient conditions in terms of LMIs for the solvability of the robust stabilisation and weighted L2-gain problems are presented respectively under the dwell time scheme. Finally, a numerical example is given to demonstrate the feasibility and effectiveness of the proposed results.

  8. A Biomechanical Assessment of Hand/Arm Force with Pneumatic Nail Gun Actuation Systems

    PubMed Central

    Lowe, Brian D.; Albers, James; Hudock, Stephen D.

    2015-01-01

    A biomechanical model is presented, and combined with measurements of tip press force, to estimate total user hand force associated with two pneumatic nail gun trigger systems. The contact actuation trigger (CAT) can fire a nail when the user holds the trigger depressed first and then “bumps” the nail gun tip against the workpiece. With a full sequential actuation trigger (SAT) the user must press the tip against the workpiece prior to activating the trigger. The SAT is demonstrably safer in reducing traumatic injury risk, but increases the duration (and magnitude) of tip force exertion. Time integrated (cumulative) hand force was calculated for a single user from measurements of the tip contact force with the workpiece and transfer time between nails as inputs to a static model of the nail gun and workpiece in two nailing task orientations. The model shows the hand force dependence upon the orientation of the workpiece in addition to the trigger system. Based on standard time allowances from work measurement systems (i.e. Methods-Time Measurement - 1) it is proposed that efficient application of hand force with the SAT in maintaining tip contact can reduce force exertion attributable to the sequential actuation trigger to 2–8% (horizontal nailing) and 9–20% (vertical nailing) of the total hand/arm force. The present model is useful for considering differences in cumulative hand/arm force exposure between the SAT and CAT systems and may explain the appeal of the CAT trigger in reducing the user’s perception of muscular effort. PMID:26321780

  9. Progress on femtosecond laser-based system-materials: three-dimensional monolithic electrostatic micro-actuator for optomechanics

    NASA Astrophysics Data System (ADS)

    Yang, Tao; Bellouard, Yves

    2016-03-01

    Femtosecond laser-dielectric interaction in a three-dimensional (3D) manner defines a capable platform for integrated 3D micro-devices fabricated out of a single piece of system-material. Here, we add a new function to femtosecond laserbased single monolith in amorphous fused silica by demonstrating a transparent 3D micro-actuator using non-ablative femtosecond laser micromachining with subsequent chemical etching. The actuation principle is based on dielectrophoresis (DEP), defined as the unbalanced electrostatic action on dielectrics, due to an induced dipole moment under a non-uniform electric field. An analytical model of this actuation scheme is proposed, which is capable of performance prediction, design parameter optimization and motion instability analysis. Furthermore, the static and dynamic performances are experimentally characterized using optical measurement methods. An actuation range of 30 μm is well attainable; resonances and the settling time in transient responses are measured; the quality factor and the bandwidth for the primary vertical resonance are also evaluated. Experimental results are in good consistence with theoretical analyses. The proposed actuation principle suppresses the need for electrodes on the mobile, non-conductive component and is particularly interesting for moving transparent elements. Thanks to the flexibility of femtosecond laser manufacturing process, this actuation scheme can be integrated in other functionalities within monolithic transparent Micro-Electro-Mechanical Systems (MEMS) for applications like resonators, adaptive lenses and integrated photonics circuits.

  10. Self-powered sensory nerve system for civil structures using hybrid forisome actuators

    NASA Astrophysics Data System (ADS)

    Shoureshi, Rahmat A.; Shen, Amy

    2006-03-01

    In order to provide a true distributed sensor and control system for civil structures, we have developed a Structural Nervous System that mimics key attributes of a human nervous system. This nervous system is made up of building blocks that are designed based on mechanoreceptors as a fundamentally new approach for the development of a structural health monitoring and diagnostic system that utilizes the recently discovered plant-protein forisomes, a novel non-living biological material capable of sensing and actuation. In particular, our research has been focused on producing a sensory nervous system for civil structures by using forisomes as the mechanoreceptors, nerve fibers, neuronal pools, and spinocervical tract to the nodal and central processing units. This paper will present up to date results of our research, including the design and analysis of the structural nervous system.

  11. Robust neural network motion tracking control of piezoelectric actuation systems for micro/nanomanipulation.

    PubMed

    Liaw, Hwee Choo; Shirinzadeh, Bijan; Smith, Julian

    2009-02-01

    This paper presents a robust neural network motion tracking control methodology for piezoelectric actuation systems employed in micro/nanomanipulation. This control methodology is proposed for tracking of desired motion trajectories in the presence of unknown system parameters, nonlinearities including the hysteresis effect and external disturbances in the control systems. In this paper, the related control issues are investigated, and a control methodology is established including the neural networks and a sliding control scheme. In particular, the radial basis function (RBF) neural networks are chosen for function approximations. The stability of the closed-loop system, as well as the convergence of the position and velocity tracking errors to zero, is assured by the control methodology in the presence of the aforementioned conditions. An offline learning procedure is also proposed for the improvement of the motion tracking performance. Precise tracking results of the proposed control methodology for a desired motion trajectory are demonstrated in the experimental study. With such a motion tracking capability, the proposed control methodology promises the realization of high-performance piezoelectric actuated micro/nanomanipulation systems.

  12. An in situ heater for a phase-change-material-based actuation system

    NASA Astrophysics Data System (ADS)

    Sant, Himanshu J.; Ho, Tammy; Gale, Bruce K.

    2010-08-01

    This paper reports efforts to develop paraffin actuators that rely on a phase change to achieve actuation. While paraffin phase-change actuators have existed for some time, this work relies on heating the paraffin in situ, rather than using external heaters. Graphite is used to create an in situ heater that utilizes resistive heating as a voltage is applied across the graphite-paraffin wax mixture. The main motivation behind this work is to reduce the actuation time and power required. An added advantage of the developed in situ heater is the use of printed circuit board technology to fabricate the prototypes rapidly and in a cost-effective manner. A video microscope and IR camera are used to characterize the performance of the actuators built in this work. Different compositions of graphite in paraffin wax are used to measure the actuator performance characteristics such as actuation time, actuation height and power required. Both dc and a pulsed power input are used to test the prototypes. Comparison with a similar actuator that utilizes a thin film heater shows a 90% reduction in actuation time for similar power usage. The actuator developed as part of this work resulted in 0.577 mm dot height at 0.69 W power input in 6 s translating to ~4 J/actuation for an actuator chamber of 2.82 µL. A new performance metric, 'effective actuation time (W s-1 mm-4)', is used to compare the performance of this technology with other phase-change-material-based actuators, and the actuator developed in this work is found to be 10 to 200 times better.

  13. Decentralized Adaptive Control of Systems with Uncertain Interconnections, Plant-Model Mismatch and Actuator Failures

    NASA Technical Reports Server (NTRS)

    Patre, Parag; Joshi, Suresh M.

    2011-01-01

    Decentralized adaptive control is considered for systems consisting of multiple interconnected subsystems. It is assumed that each subsystem s parameters are uncertain and the interconnection parameters are not known. In addition, mismatch can exist between each subsystem and its reference model. A strictly decentralized adaptive control scheme is developed, wherein each subsystem has access only to its own state but has the knowledge of all reference model states. The mismatch is estimated online for each subsystem and the mismatch estimates are used to adaptively modify the corresponding reference models. The adaptive control scheme is extended to the case with actuator failures in addition to mismatch.

  14. Magnetically Actuated Seal

    NASA Technical Reports Server (NTRS)

    Pinera, Alex

    2013-01-01

    This invention is a magnetically actuated seal in which either a single electromagnet, or multiple electromagnets, are used to control the seal's position. This system can either be an open/ close type of system or an actively controlled system.

  15. Numerical simulation of the actuation system for the ALDF's propulsion control valve. [Aircraft Landing Dynamics Facility

    NASA Technical Reports Server (NTRS)

    Korte, John J.

    1990-01-01

    A numerical simulation of the actuation system for the propulsion control valve (PCV) of the NASA Langley Aircraft Landing Dynamics Facility was developed during the preliminary design of the PCV and used throughout the entire project. The simulation is based on a predictive model of the PCV which is used to evaluate and design the actuation system. The PCV controls a 1.7 million-pound thrust water jet used in propelling a 108,000-pound test carriage. The PCV can open and close in 0.300 second and deliver over 9,000 gallons of water per sec at pressures up to 3150 psi. The numerical simulation results are used to predict transient performance and valve opening characteristics, specify the hydraulic control system, define transient loadings on components, and evaluate failure modes. The mathematical model used for numerically simulating the mechanical fluid power system is described, and numerical results are demonstrated for a typical opening and closing cycle of the PCV. A summary is then given on how the model is used in the design process.

  16. An Analytic Model for the Success Rate of a Robotic Actuator System in Hitting Random Targets

    PubMed Central

    Bradley, Stuart

    2015-01-01

    Autonomous robotic systems are increasingly being used in a wide range of applications such as precision agriculture, medicine, and the military. These systems have common features which often includes an action by an “actuator” interacting with a target. While simulations and measurements exist for the success rate of hitting targets by some systems, there is a dearth of analytic models which can give insight into, and guidance on optimization, of new robotic systems. The present paper develops a simple model for estimation of the success rate for hitting random targets from a moving platform. The model has two main dimensionless parameters: the ratio of actuator spacing to target diameter; and the ratio of platform distance moved (between actuator “firings”) to the target diameter. It is found that regions of parameter space having specified high success are described by simple equations, providing guidance on design. The role of a “cost function” is introduced which, when minimized, provides optimization of design, operating, and risk mitigation costs. PMID:26610500

  17. Multi-objective H ∞ control for vehicle active suspension systems with random actuator delay

    NASA Astrophysics Data System (ADS)

    Li, Hongyi; Liu, Honghai; Hand, Steve; Hilton, Chris

    2012-12-01

    This article is concerned with the problem of multi-objective H ∞ control for vehicle active suspension systems with random actuator delay, which can be represented by signal probability distribution. First, the dynamical equations of a quarter-car suspension model are established for the control design purpose. Secondly, when taking into account vehicle performance requirements, namely, ride comfort, suspension deflection and the probability distributed actuator delay, we present the corresponding dynamic system, which will be transformed to the stochastic system for the problem of multi-objective H ∞ controller design. Third, based on the stochastic stability theory, the state feedback controller is proposed to render that the closed-loop system is exponentially stable in mean-square while simultaneously satisfying H ∞ performance and the output constraint requirement. The presented condition is expressed in the form of convex optimisation problems so that it can be efficiently solved via standard numerical software. Finally, a practical design example is given to demonstrate the effectiveness of the proposed method.

  18. Improved Electrohydraulic Linear Actuators

    NASA Technical Reports Server (NTRS)

    Hamtil, James

    2004-01-01

    A product line of improved electrohydraulic linear actuators has been developed. These actuators are designed especially for use in actuating valves in rocket-engine test facilities. They are also adaptable to many industrial uses, such as steam turbines, process control valves, dampers, motion control, etc. The advantageous features of the improved electrohydraulic linear actuators are best described with respect to shortcomings of prior electrohydraulic linear actuators that the improved ones are intended to supplant. The flow of hydraulic fluid to the two ports of the actuator cylinder is controlled by a servo valve that is controlled by a signal from a servo amplifier that, in turn, receives an analog position-command signal (a current having a value between 4 and 20 mA) from a supervisory control system of the facility. As the position command changes, the servo valve shifts, causing a greater flow of hydraulic fluid to one side of the cylinder and thereby causing the actuator piston to move to extend or retract a piston rod from the actuator body. A linear variable differential transformer (LVDT) directly linked to the piston provides a position-feedback signal, which is compared with the position-command signal in the servo amplifier. When the position-feedback and position-command signals match, the servo valve moves to its null position, in which it holds the actuator piston at a steady position.

  19. Design of feedback control systems for unstable plants with saturating actuators

    NASA Technical Reports Server (NTRS)

    Kapasouris, Petros; Athans, Michael; Stein, Gunter

    1988-01-01

    A new control design methodology is introduced for multi-input/multi-output systems with unstable open loop plants and saturating actuators. A control system is designed using well known linear control theory techniques and then a reference prefilter is introduced so that when the references are sufficiently small, the control system operates linearly as designated. For signals large enough to cause saturations, the control law is modified in such a way to ensure stability and to preserve, to the extent possible, the behavior of the linear control design. Key benefits of this methodology are: the modified feedback system never produces saturating control signals, integrators and/or slow dynamics in the compensator never windup, the directionaL properties of the controls are maintained, and the closed loop system has certain guaranteed stability properties. The advantages of the new design methodology are illustrated in the simulation of an approximation of the AFTI-16 (Advanced Fighter Technology Integration) aircraft multivariable longitudinal dynamics.

  20. Adaptive fuzzy backstepping control for a class of switched nonlinear systems with actuator faults

    NASA Astrophysics Data System (ADS)

    Hou, Yingxue; Tong, Shaocheng; Li, Yongming

    2016-11-01

    This paper investigates the problem of fault-tolerant control (FTC) for a class of switched nonlinear systems. These systems are under arbitrary switchings and are subject to both lock-in-place and loss-of-effectiveness actuator faults. In the control design, fuzzy logic systems are used to identify the unknown switched nonlinear systems. Under the framework of the backstepping control design, FTC, fuzzy adaptive control and common Lyapunov function stability theory, an adaptive fuzzy control approach is developed. It is proved that the proposed control approach can guarantee that all the signals in the closed-loop switched system are semi-globally uniformly ultimately bounded (SGUUB) and the tracking error remains an adjustable neighbourhood of the origin. Two simulation examples are provided to illustrate the effectiveness of the proposed approach.

  1. Dynamic characteristics of a hydraulic amplification mechanism for large displacement actuators systems.

    PubMed

    Arouette, Xavier; Matsumoto, Yasuaki; Ninomiya, Takeshi; Okayama, Yoshiyuki; Miki, Norihisa

    2010-01-01

    We have developed a hydraulic displacement amplification mechanism (HDAM) and studied its dynamic response when combined with a piezoelectric actuator. The HDAM consists of an incompressible fluid sealed in a microcavity by two largely deformable polydimethylsiloxane (PDMS) membranes. The geometry with input and output surfaces having different cross-sectional areas creates amplification. By combining the HDAM with micro-actuators, we can amplify the input displacement generated by the actuators, which is useful for applications requiring large deformation, such as tactile displays. We achieved a mechanism offering up to 18-fold displacement amplification for static actuation and 12-fold for 55 Hz dynamic actuation. PMID:22319281

  2. Neural network-based robust actuator fault diagnosis for a non-linear multi-tank system.

    PubMed

    Mrugalski, Marcin; Luzar, Marcel; Pazera, Marcin; Witczak, Marcin; Aubrun, Christophe

    2016-03-01

    The paper is devoted to the problem of the robust actuator fault diagnosis of the dynamic non-linear systems. In the proposed method, it is assumed that the diagnosed system can be modelled by the recurrent neural network, which can be transformed into the linear parameter varying form. Such a system description allows developing the designing scheme of the robust unknown input observer within H∞ framework for a class of non-linear systems. The proposed approach is designed in such a way that a prescribed disturbance attenuation level is achieved with respect to the actuator fault estimation error, while guaranteeing the convergence of the observer. The application of the robust unknown input observer enables actuator fault estimation, which allows applying the developed approach to the fault tolerant control tasks.

  3. Two-Dimensional Scramjet Inlet Unstart Model: Wind-Tunnel Blockage and Actuation Systems Test

    NASA Technical Reports Server (NTRS)

    Holland, Scott D.

    1994-01-01

    This supplement to NASA TM 109152 shows the Schlieren video (10 min. 52 sec., color, Beta and VHS) of the external flow field and a portion of the internal flow field of a two-dimensional scramjet inlet model in the NASA Langley 20-Inch Mach 6 Tunnel. The intent of the overall test program is to study (both experimentally and computationally) the dynamics of the inlet unstart; this (phase I) effort examines potential wind-tunnel blockage issues related to model sizing and the adequacy of the actuation systems in accomplishing the start and unstart. The model is equipped with both a moveable cowl and aft plug. Windows in the inlet sidewalls allow limited optical access to the internal shock structure. In the video, flow is from right to left, and the inlet is oriented inverted with respect to flight, i.e., with the cowl on top. The plug motion is obvious because the plug is visible in the aft window. The cowl motion, however, is not as obvious because the cowl is hidden from view by the inlet sidewall. The end of the cowl actuator arm, however, becomes visible above the inlet sidewalls between the windows when the cowl is up (see figure 1b of the primary document). The model is injected into the tunnel and observed though several actuation sequences with two plug configurations over a range of unit freestream Reynolds number at a nominal freestream Mach number of 6. The framing rate and shutter speed of the camera were too slow to fully capture the dynamics of the unstart but did prove sufficient to identify inlet start and unstart. This series of tests indicated that the model was appropriately sized for this facility and identified operability limits required first to allow the inlet to start and second to force the unstart.

  4. Robust H∞ stabilization of a hard disk drive system with a single-stage actuator

    NASA Astrophysics Data System (ADS)

    Harno, Hendra G.; Kiin Woon, Raymond Song

    2015-04-01

    This paper considers a robust H∞ control problem for a hard disk drive system with a single stage actuator. The hard disk drive system is modeled as a linear time-invariant uncertain system where its uncertain parameters and high-order dynamics are considered as uncertainties satisfying integral quadratic constraints. The robust H∞ control problem is transformed into a nonlinear optimization problem with a pair of parameterized algebraic Riccati equations as nonconvex constraints. The nonlinear optimization problem is then solved using a differential evolution algorithm to find stabilizing solutions to the Riccati equations. These solutions are used for synthesizing an output feedback robust H∞ controller to stabilize the hard disk drive system with a specified disturbance attenuation level.

  5. Parameter-dependent vibration-attenuation controller design for electro-hydraulic actuated linear structural systems

    NASA Astrophysics Data System (ADS)

    Weng, Falu; Mao, Weijie

    2012-03-01

    The problem of robust active vibration control for a class of electro-hydraulic actuated structural systems with time-delay in the control input channel and parameter uncertainties appearing in all the mass, damping and stiffness matrices is investigated in this paper. First, by introducing a linear varying parameter, the nonlinear system is described as a linear parameter varying (LPV) model. Second, based on this LPV model, an LMI-based condition for the system to be asymptotically stabilized is deduced. By solving these LMIs, a parameter-dependent controller is established for the closedloop system to be stable with a prescribed level of disturbance attenuation. The condition is also extended to the uncertain case. Finally, some numerical simulations demonstrate the satisfying performance of the proposed controller.

  6. A system identification approach to the characterization and control of a piezoelectric tube actuator

    NASA Astrophysics Data System (ADS)

    Mohammadzaheri, Morteza; Grainger, Steven; Bazghaleh, Mohsen

    2013-10-01

    This paper addresses the sensorless control of piezoelectric tube actuators to avoid the expense and practical limits of displacement sensors in nanopositioning applications. Three electrical signals have traditionally been used to estimate displacement: the piezoelectric voltage, the voltage induced in sensing electrodes and the voltage across a sensing resistor. In this work, the piezoelectric voltage was employed to estimate displacement; the use of this signal does not necessitate drift removal like the sensing voltage, and its superiority over the induced voltage is shown in this paper. The piezoelectric voltage is the actuating signal, so a feedforward architecture based on an inverse model is used for sensorless control. Inspired by internal model control (IMC), a filter together with the inverted model of the system, derived using system identification techniques, was used as the feedforward controller. The fixed-slope-input effect is illustrated as a prominent source of control error in tracking triangular references, then an additional nonlinear control command is proposed to address this effect and improve the control performance.

  7. Large thermal protection system panel

    NASA Technical Reports Server (NTRS)

    Myers, Franklin K. (Inventor); Weinberg, David J. (Inventor); Tran, Tu T. (Inventor)

    2003-01-01

    A protective panel for a reusable launch vehicle provides enhanced moisture protection, simplified maintenance, and increased temperature resistance. The protective panel includes an outer ceramic matrix composite (CMC) panel, and an insulative bag assembly coupled to the outer CMC panel for isolating the launch vehicle from elevated temperatures and moisture. A standoff attachment system attaches the outer CMC panel and the bag assembly to the primary structure of the launch vehicle. The insulative bag assembly includes a foil bag having a first opening shrink fitted to the outer CMC panel such that the first opening and the outer CMC panel form a water tight seal at temperatures below a desired temperature threshold. Fibrous insulation is contained within the foil bag for protecting the launch vehicle from elevated temperatures. The insulative bag assembly further includes a back panel coupled to a second opening of the foil bag such that the fibrous insulation is encapsulated by the back panel, the foil bag, and the outer CMC panel. The use of a CMC material for the outer panel in conjunction with the insulative bag assembly eliminates the need for waterproofing processes, and ultimately allows for more efficient reentry profiles.

  8. Optimal Control Modification for Robust Adaptation of Singularly Perturbed Systems with Slow Actuators

    NASA Technical Reports Server (NTRS)

    Nguyen, Nhan T.; Ishihara, Abraham; Stepanyan, Vahram; Boskovic, Jovan

    2009-01-01

    Recently a new optimal control modification has been introduced that can achieve robust adaptation with a large adaptive gain without incurring high-frequency oscillations as with the standard model-reference adaptive control. This modification is based on an optimal control formulation to minimize the L2 norm of the tracking error. The optimal control modification adaptive law results in a stable adaptation in the presence of a large adaptive gain. This study examines the optimal control modification adaptive law in the context of a system with a time scale separation resulting from a fast plant with a slow actuator. A singular perturbation analysis is performed to derive a modification to the adaptive law by transforming the original system into a reduced-order system in slow time. The model matching conditions in the transformed time coordinate results in increase in the feedback gain and modification of the adaptive law.

  9. Limiting vibration in systems with constant amplitude actuators through command preshaping. M.S Thesis - MIT

    NASA Technical Reports Server (NTRS)

    Rogers, Keith Eric

    1994-01-01

    The basic concepts of command preshaping were taken and adapted to the framework of systems with constant amplitude (on-off) actuators. In this context, pulse sequences were developed which help to attenuate vibration in flexible systems with high robustness to errors in frequency identification. Sequences containing impulses of different magnitudes were approximated by sequences containing pulses of different durations. The effects of variation in pulse width on this approximation were examined. Sequences capable of minimizing loads induced in flexible systems during execution of commands were also investigated. The usefulness of these techniques in real-world situations was verified by application to a high fidelity simulation of the space shuttle. Results showed that constant amplitude preshaping techniques offer a substantial improvement in vibration reduction over both the standard and upgraded shuttle control methods and may be mission enabling for use of the shuttle with extremely massive payloads.

  10. Output-feedback control for switched linear systems subject to actuator saturation

    NASA Astrophysics Data System (ADS)

    Duan, Chang; Wu, Fen

    2012-10-01

    This article is devoted to the output-feedback ℋ∞ control problem for switched linear systems subject to actuator saturation. We consider both continuous- and discrete-time switched systems. Using the minimal switching rule, nonlinear output feedbacks expressed in the form of quasi-linear parameter varying system are designed to satisfy a pre-specified disturbance attenuation level defined by the regional ℒ2 (ℓ2)-gains over a class of energy-bounded disturbances. The conditions are expressed in bilinear matrix inequalities and can be solved by line search coupled with linear matrix inequalities optimisation. A spherical inverted pendulum example is used to illustrate the effectiveness of the proposed approach.

  11. Design of an Active Bumper with a Series Elastic Actuator for Pedestrian Protection of Small Unmanned Vehicles

    NASA Astrophysics Data System (ADS)

    Terumasa, Narukawa; Tomoki, Tsuge; Hiroshi, Yamamoto; Takahiro, Suzuki

    2016-09-01

    When autonomous unmanned vehicles are operated on sidewalks, the vehicles must have high safety standards such as avoiding injury when they come in contact with pedestrians. In this study, we established a design for preventing serious injury when such collisions occur. We designed an active bumper with a series elastic actuator, with the goal of avoiding serious injury to a pedestrian in a collision with a small unmanned vehicle. The series elastic actuator comprised an elastic element in series with a table driven by a ball screw and servo motor. The active bumper was used to control the contact force between a vehicle and a pedestrian. The optimal force for minimizing the deflection of the object of the collision was derived, and the actuator controlled to apply this optimal force. Numerical simulations showed that the active bumper was successful in improving the collision safety of small unmanned vehicles.

  12. Creep-Fatigue Relationsihps in Electroactive Polymer Systems and Predicted Effects in an Actuator Design

    NASA Technical Reports Server (NTRS)

    Vinogradov, Aleksandra M.; Ihlefeld, Curtis M.; Henslee, Issac

    2009-01-01

    The paper concerns the time-dependent behavior of electroactive polymers (EAP) and their use in advanced intelligent structures for space exploration. Innovative actuator design for low weight and low power valves required in small plants planned for use on the moon for chemical analysis is discussed. It is shown that in-depth understanding of cyclic loading effects observed through accelerated creep rates due to creep-fatigue interaction in polymers is critical in terms of proper functioning of EAP based actuator devices. In the paper, an overview of experimental results concerning the creep properties and cyclic creep response of a thin film piezoelectric polymer polyvinylidene fluoride (PVDF) is presented. The development of a constitutive creep-fatigue interaction model to predict the durability and service life of electroactive polymers is discussed. A novel method is proposed to predict damage accumulation and fatigue life of polymers under oyclic loading conditions in the presence of creep. The study provides a basis for ongoing research initiatives at the NASA Kennedy Space Center in the pursuit of new technologies using EAP as active elements for lunar exploration systems.

  13. Fast breeder reactor protection system

    DOEpatents

    van Erp, J.B.

    1973-10-01

    Reactor protection is provided for a liquid-metal-fast breeder reactor core by measuring the coolant outflow temperature from each of the subassemblies of the core. The outputs of the temperature sensors from a subassembly region of the core containing a plurality of subassemblies are combined in a logic circuit which develops a scram alarm if a predetermined number of the sensors indicate an over temperature condition. The coolant outflow from a single subassembly can be mixed with the coolant outflow from adjacent subassemblies prior to the temperature sensing to increase the sensitivity of the protection system to a single subassembly failure. Coherence between the sensors can be required to discriminate against noise signals. (Official Gazette)

  14. Dynamic Head-Disk Interface Modeling and Adaptive Control of a Hybrid Actuator for Optical Data Storage Systems

    NASA Astrophysics Data System (ADS)

    Wu, Zhizheng; Li, Yang; Wang, Pei; Liu, Mei

    2015-01-01

    In the near-field recording (NFR) system, the gap between the lens and disk will drop down to 100 nm. However, the disk vibration and force disturbance make it difficult to maintain the desired flying height during disk operation, and the lens-disk collision can easily occur. It is proposed in this article to design a hybrid actuator system which combines both advantages of the flying slider used in hard disk drives and the voice coil actuator used in optical disk drives. The dynamic head-disk interface model of the hybrid actuator is first developed, then an adaptive regulation approach is proposed to control the flying height at its desired value despite the unknown disturbances. Simulation and experimental results are presented to illustrate the effectiveness of the proposed flying height control approach.

  15. Artificial muscle actuators for haptic displays: system design to match the dynamics and tactile sensitivity of the human fingerpad

    NASA Astrophysics Data System (ADS)

    Biggs, S. James; Hitchcock, Roger N.

    2010-04-01

    Electroactive Polymer Artificial Muscles (EPAMTM) based on dielectric elastomers have the bandwidth and the energy density required to make haptic displays that are both responsive and compact. Recent work at Artificial Muscle Inc. has been directed toward the development of thin, high-fidelity haptic modules for mobile handsets. The modules provide the brief tactile "click" that confirms key press, and the steady state "bass" effects that enhance gaming and music. To design for these capabilities we developed a model of the physical system comprised of the actuator, handset, and user. Output of the physical system was passed through a transfer function to covert vibration into an estimate of the intensity of the user's haptic sensation. A model of fingertip impedance versus button press force is calibrated to data, as is impedance of the palm holding a handset. An energy-based model of actuator performance is derived and calibrated, and the actuator geometry is tuned for good haptic performance.

  16. Quiet Clean Short-haul Experimental Engine (QCSEE): Hamilton Standard cam/harmonic drive variable pitch fan actuation system detail design report

    NASA Technical Reports Server (NTRS)

    1976-01-01

    A variable pitch fan actuation system was designed which incorporates a remote nacelle-mounted blade angle regulator. The regulator drives a rotating fan-mounted mechanical actuator through a flexible shaft and differential gear train. The actuator incorporates a high ratio harmonic drive attached to a multitrack spherical cam which changes blade pitch through individual cam follower arms attached to each blade trunnion. Detail design parameters of the actuation system are presented. These include the following: design philosophies, operating limits, mechanical, hydraulic and thermal characteristics, mechanical efficiencies, materials, weights, lubrication, stress analyses, reliability and failure analyses.

  17. An evaluation plan of bus architectures and protocols using the NASA Ames intelligent redundant actuation system

    NASA Technical Reports Server (NTRS)

    Defeo, P.; Chen, M.

    1987-01-01

    Means for evaluating data bus architectures and protocols for highly integrated flight control system applications are needed. Described are the criteria and plans to do this by using the NASA/Ames Intelligent Redundant Actuation System (IRAS) experimental set-up. Candidate bus architectures differ from one another in terms of: topology, access control, message transfer schemes, message characteristics, initialization. data flow control, transmission rates, fault tolerance, and time synchronization. The evaluation criteria are developed relative to these features. A preliminary, analytical evaluation of four candidate busses (MIL-STD-1553B, DATAC, Ethernet, and HSIS) is described. A bus must be exercised in a real-time environment to evaluate its dynamic characteristics. A plan for real-time evaluation of these four busses using a combination of hardware and simulation techniques is presented.

  18. Adaptive NN Control of a Class of Nonlinear Systems With Asymmetric Saturation Actuators.

    PubMed

    Ma, Jianjun; Ge, Shuzhi Sam; Zheng, Zhiqiang; Hu, Dewen

    2015-07-01

    In this note, adaptive neural network (NN) control is investigated for a class of uncertain nonlinear systems with asymmetric saturation actuators and external disturbances. To handle the effect of nonsmooth asymmetric saturation nonlinearity, a Gaussian error function-based continuous differentiable asymmetric saturation model is employed such that the backstepping technique can be used in the control design. The explosion of complexity in traditional backstepping design is avoided using dynamic surface control. Using radial basis function NN, adaptive control is developed to guarantee that all the signals in the closed-loop system are semiglobally uniformly ultimately bounded, and the tracking error converges to a small neighborhood of origin by appropriately choosing design constants. The effectiveness of the proposed control is demonstrated in the simulation study.

  19. Development of a three-dimensional scanning microparticle image velocimetry system using a piezo actuator

    SciTech Connect

    Shinohara, Kyosuke; Sugii, Yasuhiko; Jeong, Jae Hong; Okamoto, Koji

    2005-10-15

    A technique for measuring the full field (x,y,z,u,v,w) velocity distribution of fluid flow at a micrometer scale spatial resolution has been developed. To investigate three-dimensional (3D) flow structures on a microscopic scale, a 3D scanning microparticle image velocimetry system was developed by combining a high-speed camera, an epifluorescent microscope, a cw laser, and a piezo actuator. Both numerical simulations and an experiment were carried out in order to validate the measurement accuracy of the system. Optimum measurement conditions were determined by numerical simulations using synthetic images under epifluorescent microscope observation. As a demonstration, the three-dimensional velocity distribution of water flow inside a microround tube having a diameter of 95 {mu}m was measured at a spatial resolution of 5.4x2.7x4.2 {mu}m.

  20. Development of Characterization Tools for Reliability Testing of MicroElectroMechanical System Actuators

    SciTech Connect

    Allen, James J.; Eaton, William P.; Smith, Norman F.; Tanner, Danelle M.

    1999-07-26

    Characterization tools have been developed to study the performance characteristics and reliability of surface micromachined actuators. These tools include (1) the ability to electrically stimulate or stress the actuator, (2) the capability to visually inspect the devices in operation, (3) a method for capturing operational information, and (4) a method to extract performance characteristics from the operational information. Additionally, a novel test structure has been developed to measure electrostatic forces developed by a comb drive actuator.

  1. Preliminary Sizings for an Integrated SME Actuator System for the STAR system

    NASA Technical Reports Server (NTRS)

    Jardine, A. Peter

    2004-01-01

    The Star configuration consists of three legs of an aperature of total diameter of 2.5 m diameter. For the purposes of this initial study for actuator requirements, several assumptions were made. For support, we assumed that the membrane was Upilex of a thickness of 0.010 in. thick, and with a modulus of approximately YYY. Upilex was chosen as being relatively commercially available and is compatible with either TiNi or AuCd manufacture. We confined the areas in which we could apply actuators to three strips of length 2.5 meters and width of 0.1 m. This brings the problem to a solution of a strip.

  2. Teleoperation System with Hybrid Pneumatic-Piezoelectric Actuation for MRI-Guided Needle Insertion with Haptic Feedback

    PubMed Central

    Shang, Weijian; Su, Hao; Li, Gang; Fischer, Gregory S.

    2014-01-01

    This paper presents a surgical master-slave tele-operation system for percutaneous interventional procedures under continuous magnetic resonance imaging (MRI) guidance. This system consists of a piezoelectrically actuated slave robot for needle placement with integrated fiber optic force sensor utilizing Fabry-Perot interferometry (FPI) sensing principle. The sensor flexure is optimized and embedded to the slave robot for measuring needle insertion force. A novel, compact opto-mechanical FPI sensor interface is integrated into an MRI robot control system. By leveraging the complementary features of pneumatic and piezoelectric actuation, a pneumatically actuated haptic master robot is also developed to render force associated with needle placement interventions to the clinician. An aluminum load cell is implemented and calibrated to close the impedance control loop of the master robot. A force-position control algorithm is developed to control the hybrid actuated system. Teleoperated needle insertion is demonstrated under live MR imaging, where the slave robot resides in the scanner bore and the user manipulates the master beside the patient outside the bore. Force and position tracking results of the master-slave robot are demonstrated to validate the tracking performance of the integrated system. It has a position tracking error of 0.318mm and sine wave force tracking error of 2.227N. PMID:25126446

  3. Controllable nanoscale rotating actuator system based on carbon nanotube and graphene

    NASA Astrophysics Data System (ADS)

    Huang, Jianzhang; Han, Qiang

    2016-04-01

    A controllable nanoscale rotating actuator system consisting of a double carbon nanotube and graphene driven by a temperature gradient is proposed, and its rotating dynamics performance and driving mechanism are investigated through molecular dynamics simulations. The outer tube exhibits stable pure rotation with certain orientation under temperature gradient and the steady rotational speed rises as the temperature gradient increases. It reveals that the driving torque is caused by the difference of atomic van der Waals potentials due to the temperature gradient and geometrical features of carbon nanotube. A theoretical model for driving torque is established based on lattice dynamics theory and its predicted results agree well with molecular dynamics simulations. Further discussion is taken according to the theoretical model. The work in this study would be a guide for design and application of controllable nanoscale rotating devices based on carbon nanotubes and graphene.

  4. Output feedback control of linear fractional transformation systems subject to actuator saturation

    NASA Astrophysics Data System (ADS)

    Ban, Xiaojun; Wu, Fen

    2016-11-01

    In this paper, the control problem for a class of linear parameter varying (LPV) plant subject to actuator saturation is investigated. For the saturated LPV plant depending on the scheduling parameters in linear fractional transformation (LFT) fashion, a gain-scheduled output feedback controller in the LFT form is designed to guarantee the stability of the closed-loop LPV system and provide optimised disturbance/error attenuation performance. By using the congruent transformation, the synthesis condition is formulated as a convex optimisation problem in terms of a finite number of LMIs for which efficient optimisation techniques are available. The nonlinear inverted pendulum problem is employed to demonstrate the effectiveness of the proposed approach. Moreover, the comparison between our LPV saturated approach with an existing linear saturated method reveals the advantage of the LPV controller when handling nonlinear plants.

  5. Neural network-based adaptive consensus tracking control for multi-agent systems under actuator faults

    NASA Astrophysics Data System (ADS)

    Zhao, Lin; Jia, Yingmin

    2016-06-01

    In this paper, a distributed output feedback consensus tracking control scheme is proposed for second-order multi-agent systems in the presence of uncertain nonlinear dynamics, external disturbances, input constraints, and partial loss of control effectiveness. The proposed controllers incorporate reduced-order filters to account for the unmeasured states, and the neural networks technique is implemented to approximate the uncertain nonlinear dynamics in the synthesis of control algorithms. In order to compensate the partial loss of actuator effectiveness faults, fault-tolerant parts are included in controllers. Using the Lyapunov approach and graph theory, it is proved that the controllers guarantee a group of agents that simultaneously track a common time-varying state of leader, even when the state of leader is available only to a subset of the members of a group. Simulation results are provided to demonstrate the effectiveness of the proposed consensus tracking method.

  6. Enhanced iterative learning control for a piezoelectric actuator system using wavelet transform filtering

    NASA Astrophysics Data System (ADS)

    Chien, Chiang-Ju; Lee, Fu-Shin; Wang, Jhen-Cheng

    2007-01-01

    For trajectory tracking of a piezoelectric actuator system, an enhanced iterative learning control (ILC) scheme based on wavelet transform filtering (WTF) is proposed in this research. The enhanced ILC scheme incorporates a state compensation in the ILC formula. Combining state compensation with iterative learning, the scheme enhances tracking accuracies substantially, in comparison to the conventional D-type ILC and a proportional control-aided D-type ILC. The wavelet transform is adopted to filter learnable tracking errors without phase shift. Based on both a time-frequency analysis of tracking errors and a convergence bandwidth analysis of ILC, a two-level WTF is chosen for ILC in this study. The enhanced ILC scheme using WTF was applied to track two desired trajectories, one with a single frequency and the other with multiple frequencies, respectively. Experimental results validate the efficacy of the enhanced ILC in terms of the speed of convergence and the level of long-term tracking errors.

  7. Switching sliding mode force tracking control of piezoelectric-hydraulic pump-based friction element actuation systems for automotive transmissions

    NASA Astrophysics Data System (ADS)

    Kim, Gi-Woo; Wang, K. W.

    2009-08-01

    In this study, a nonlinear sliding-mode controller is designed for force tracking of a piezoelectric-hydraulic pump (PHP)-based actuation system, which is developed to replace the current electro-hydraulic actuation systems for automatic transmission (AT) friction elements, such as band brakes or clutches. By utilizing the PHP, one can eliminate the various hydraulic components (oil pump, regulating valve and control valve) in current ATs and achieve a simpler configuration with more efficient operation. With the derived governing equation of motion of the PHP-based actuation system integrated with the friction element (band brake), a switching control law is synthesized based on the sliding-mode theory. To evaluate the effectiveness of the proposed control law, its force tracking performance for the engagement of a friction element during an AT 1\\to 2 up-shift is examined experimentally. It is shown that one can successfully track the desired force trajectory for AT shift control with small tracking error. This study demonstrates the potential of the PHP as a new controllable actuation system for AT friction elements.

  8. Wind-tunnel blockage and actuation systems test of a two-dimensional scramjet inlet unstart model at Mach 6

    NASA Technical Reports Server (NTRS)

    Holland, Scott D.

    1994-01-01

    The present study examines the wind-tunnel blockage and actuation systems effectiveness in starting and forcibly unstarting a two-dimensional scramjet inlet in the NASA Langley 20-Inch Mach 6 Tunnel. The intent of the overall test program is to study (both experimentally and computationally) the dynamics of the inlet unstart; however, prior to the design and fabrication of an expensive, instrumented wind-tunnel model, it was deemed necessary first to examine potential wind-tunnel blockage issues related to model sizing and to examine the adequacy of the actuation systems in accomplishing the start and unstart. The model is equipped with both a moveable cowl and aft plug. Windows in the inlet sidewalls allow limited optical access to the internal shock structure; schlieren video was used to identify inlet start and unstart. A chronology of each actuation sequence is provided in tabular form along with still frames from the schlieren video. A pitot probe monitored the freestream conditions throughout the start/unstart process to determine if there was a blockage effect due to the model start or unstart. Because the purpose of this report is to make the phase I (blockage and actuation systems) data rapidly available to the community, the data is presented largely without analysis of the internal shock interactions or the unstart process. This series of tests indicated that the model was appropriately sized for this facility and identified operability limits required first to allow the inlet to start and second to force the unstart.

  9. Hermes thermal protection system overview

    NASA Astrophysics Data System (ADS)

    Chaumette, Daniel; Cretenet, Jean-Claude

    The HERMES thermal protection system for the reentry is a new challenge for the designer. Compared to the system operational to day which is the U.S. Orbiter, the smaller size and higher cross range of HERMES are inducing higher working temperatures and a longer duration for the hot phase of the reentry. Hence the overall weight of the TPS system is comparatively more critical than on the Orbiter. On the other hand since the conception of the Orbiter a lot of new materials, namely ceramic composites, have been developped, and may lead to more efficient concepts of TPS. In the initial studies on HERMES TPS systems a lot of possibilites were considered, including External passive TPS, Hot structures, Active TPS. This selection has been now shortlisted to three basic concepts, with a number of variant or back ups still under consideration: • Ceramic composites hot structures for the nose, leading edges, fins and control surfaces • External insulation : composite ceramic shingles covering a lightweight thermal insulation (or rigid surface insulation (tiles) as a back up solution) for the hot undersurfaces and part of the upper surface. • Flexible surface insulation for the lower temperature upper surfaces. The paper presents details on the concepts being studied, the optimisation methods and the concept selection criteria.

  10. Design of a Magnetostrictive-Hydraulic Actuator Considering Nonlinear System Dynamics and Fluid-Structure Coupling

    NASA Astrophysics Data System (ADS)

    Larson, John Philip

    Smart material electro-hydraulic actuators (EHAs) utilize fluid rectification via one-way check valves to amplify the small, high-frequency vibrations of certain smart materials into large motions of a hydraulic cylinder. Although the concept has been demonstrated in previously, the operating frequency of smart material EHA systems has been limited to a small fraction of the available bandwidth of the driver materials. The focus of this work is to characterize and model the mechanical performance of a magnetostrictive EHA considering key system components: rectification valves, smart material driver, and fluid-system components, leading to an improved actuator design relative to prior work. The one-way valves were modeled using 3-D finite element analysis, and their behavior was characterized experimentally by static and dynamic experimental measurement. Taking into account the effect of the fluid and mechanical conditions applied to the valves within the pump, the dynamic response of the valve was quantified and applied to determine rectification bandwidth of different valve configurations. A novel miniature reed valve, designed for a frequency response above 10~kHz, was fabricated and tested within a magnetostrictive EHA. The nonlinear response of the magnetostrictive driver, including saturation and hysteresis effects, was modeled using the Jiles-Atherton approach to calculate the magnetization and the resulting magnetostriction based on the applied field calculated within the rod from Maxwell's equations. The dynamic pressure response of the fluid system components (pumping chamber, hydraulic cylinder, and connecting passages) was measured over a range of input frequencies. For the magnetostrictive EHA tested, the peak performance frequency was found to be limited by the fluid resonances within the system. A lumped-parameter modeling approach was applied to model the overall behavior of a magnetostrictive EHA, incorporating models for the reed valve response

  11. MEMS Actuated Deformable Mirror

    SciTech Connect

    Papavasiliou, A; Olivier, S; Barbee, T; Walton, C; Cohn, M

    2005-11-10

    This ongoing work concerns the creation of a deformable mirror by the integration of MEMS actuators with Nanolaminate foils through metal compression boning. These mirrors will use the advantages of these disparate technologies to achieve dense actuation of a high-quality, continuous mirror surface. They will enable advanced adaptive optics systems in large terrestrial telescopes. While MEMS actuators provide very dense actuation with high precision they can not provide large forces typically necessary to deform conventional mirror surfaces. Nanolaminate foils can be fabricated with very high surface quality while their extraordinary mechanical properties enable very thin, flexible foils to survive the rigors of fabrication. Precise metal compression bonding allows the attachment of the fragile MEMS actuators to the thin nanolaminate foils without creating distortions at the bond sites. This paper will describe work in four major areas: (1) modeling and design, (2) bonding development, (3) nanolaminate foil development, (4) producing a prototype. A first-principles analytical model was created and used to determine the design parameters. A method of bonding was determined that is both strong, and minimizes the localized deformation or print through. Work has also been done to produce nanolaminate foils that are sufficiently thin, flexible and flat to be deformed by the MEMS actuators. Finally a prototype was produced by bonding thin, flexible nanolaminate foils to commercially available MEMS actuators.

  12. Thermal protection system ablation sensor

    NASA Technical Reports Server (NTRS)

    Gorbunov, Sergey (Inventor); Martinez, Edward R. (Inventor); Scott, James B. (Inventor); Oishi, Tomomi (Inventor); Fu, Johnny (Inventor); Mach, Joseph G. (Inventor); Santos, Jose B. (Inventor)

    2011-01-01

    An isotherm sensor tracks space vehicle temperatures by a thermal protection system (TPS) material during vehicle re-entry as a function of time, and surface recession through calibration, calculation, analysis and exposed surface modeling. Sensor design includes: two resistive conductors, wound around a tube, with a first end of each conductor connected to a constant current source, and second ends electrically insulated from each other by a selected material that becomes an electrically conductive char at higher temperatures to thereby complete an electrical circuit. The sensor conductors become shorter as ablation proceeds and reduced resistance in the completed electrical circuit (proportional to conductor length) is continually monitored, using measured end-to-end voltage change or current in the circuit. Thermocouple and/or piezoelectric measurements provide consistency checks on local temperatures.

  13. Automating occupational protection records systems

    SciTech Connect

    Lyon, M.; Martin, J.B.

    1991-10-01

    Occupational protection records have traditionally been generated by field and laboratory personnel, assembled into files in the safety office, and eventually stored in a warehouse or other facility. Until recently, these records have been primarily paper copies, often handwritten. Sometimes, the paper is microfilmed for storage. However, electronic records are beginning to replace these traditional methods. The purpose of this paper is to provide guidance for making the transition to automated record keeping and retrieval using modern computer equipment. This paper describes the types of records most readily converted to electronic record keeping and a methodology for implementing an automated record system. The process of conversion is based on a requirements analysis to assess program needs and a high level of user involvement during the development. The importance of indexing the hard copy records for easy retrieval is also discussed. The concept of linkage between related records and its importance relative to reporting, research, and litigation will be addressed. 2 figs.

  14. Simultaneous fault detection and control for switched systems with actuator faults

    NASA Astrophysics Data System (ADS)

    Li, Jian; Yang, Guang-Hong

    2016-07-01

    This paper is concerned with the fault detection and control problem for discrete-time switched systems. The actuator faults, especially 'outage cases', are considered. The detector/controller is designed simultaneously such that the closed-loop system switches under an average dwell time, and when a fault is detected, an alarm is generated and then the controller is switched to allow the norm of the states of the subsystem to increase within the acceptable limits. Thus, a switching strategy which combines average dwell time switching with event-driven switching is proposed. Under this switching strategy, the attention is focused on designing the detector/controller such that estimation errors between residual signals and faults are minimised for the fulfillment of fault detection objectives; simultaneously, the closed-loop system becomes asymptotically stable for the fulfillment of control objectives. A two-step procedure is adopted to obtain the solutions through satisfying a set of linear matrix inequalities. An example comprising of three cases is considered. Through these cases, it is demonstrated that the fault detection and control for switched systems using a two-stage switching strategy and asynchronous switching are feasible.

  15. Dynamics of a pneumatic artificial muscle actuation system driving a trailing edge flap

    NASA Astrophysics Data System (ADS)

    Woods, Benjamin K. S.; Kothera, Curt S.; Wang, Gang; Wereley, Norman M.

    2014-09-01

    This study presents a time domain dynamic model of an antagonistic pneumatic artificial muscle (PAM) driven trailing edge flap (TEF) system for next generation active helicopter rotors. Active rotor concepts are currently being widely researched in the rotorcraft community as a means to provide a significant leap forward in performance through primary aircraft control, vibration mitigation and noise reduction. Recent work has shown PAMs to be a promising candidate for active rotor actuation due to their combination of high force, large stroke, light weight, and suitable bandwidth. When arranged into biologically inspired agonist/antagonist muscle pairs they can produce bidirectional torques for effectively driving a TEF. However, there are no analytical dynamic models in the literature that can accurately capture the behavior of such systems across the broad range of frequencies required for this demanding application. This work combines mechanical, pneumatic, and aerodynamic component models into a global flap system model developed for the Bell 407 rotor system. This model can accurately predict pressure, force, and flap angle response to pneumatic control valve inputs over a range of operating frequencies from 7 to 35 Hz (1/rev to 5/rev for the Bell 407) and operating pressures from 30 to 90 psi.

  16. Stochastic linearisation approach to performance analysis of feedback systems with asymmetric nonlinear actuators and sensors

    NASA Astrophysics Data System (ADS)

    Kabamba, P. T.; Meerkov, S. M.; Ossareh, H. R.

    2015-01-01

    This paper considers feedback systems with asymmetric (i.e., non-odd functions) nonlinear actuators and sensors. While the stability of such systems can be investigated using the theory of absolute stability and its extensions, the current paper provides a method for their performance analysis, i.e., reference tracking and disturbance rejection. Similar to the case of symmetric nonlinearities considered in earlier work, the development is based on the method of stochastic linearisation (which is akin to the describing functions, but intended to study general properties of dynamics, rather than periodic regimes). Unlike the symmetric case, however, the nonlinearities considered here must be approximated not only by a quasilinear gain, but a quasilinear bias as well. This paper derives transcendental equations for the quasilinear gain and bias, provides necessary and sufficient conditions for existence of their solutions, and, using simulations, investigates the accuracy of these solutions as a tool for predicting the quality of reference tracking and disturbance rejection. The method developed is then applied to performance analysis of specific systems, and the effect of asymmetry on their behaviour is investigated. In addition, this method is used to justify the recently discovered phenomenon of noise-induced loss of tracking in feedback systems with PI controllers, anti-windup, and sensor noise.

  17. Design of virtual display and testing system for moving mass electromechanical actuator

    NASA Astrophysics Data System (ADS)

    Gao, Zhigang; Geng, Keda; Zhou, Jun; Li, Peng

    2015-12-01

    Aiming at the problem of control, measurement and movement virtual display of moving mass electromechanical actuator(MMEA), the virtual testing system of MMEA was developed based on the PC-DAQ architecture and the software platform of LabVIEW, and the comprehensive test task such as drive control of MMEA, tests of kinematic parameter, measurement of centroid position and virtual display of movement could be accomplished. The system could solve the alignment for acquisition time between multiple measurement channels in different DAQ cards, then on this basis, the researches were focused on the dynamic 3D virtual display by the LabVIEW, and the virtual display of MMEA were realized by the method of calling DLL and the method of 3D graph drawing controls. Considering the collaboration with the virtual testing system, including the hardware drive, the measurement software of data acquisition, and the 3D graph drawing controls method was selected, which could obtained the synchronization measurement, control and display. The system can measure dynamic centroid position and kinematic position of movable mass block while controlling the MMEA, and the interface of 3D virtual display has realistic effect and motion smooth, which can solve the problem of display and playback about MMEA in the closed shell.

  18. Field emission in actuation pads of radio frequency microelectromechanical systems ohmic switches: A potential contamination mechanism

    NASA Astrophysics Data System (ADS)

    Koutsoureli, M.; Reig, B.; Papandreou, E.; Poulain, C.; Souchon, F.; Deborgies, F.; Papaioannou, G.

    2016-01-01

    The field emission current generated across the actuation pads in ohmic MEMS switches during ON state is shown to constitute an additional source of degradation. Switches with Au/Au and Au/Ru contacts have been subjected to 24 h continuous stress. In both cases the switch ohmic contact resistance and field emission current across actuation pads were monitored simultaneously. The experimental results revealed a negligible degradation in Au/Au contact devices while the Au/Ru contact devices show a fast degradation. The experimental results from Au/Au and Ru/Au contact switches have been compared taking into account the plasma generation in the actuation pads.

  19. Modeling and motion compensation of a bidirectional tendon-sheath actuated system for robotic endoscopic surgery.

    PubMed

    Sun, Zhenglong; Wang, Zheng; Phee, Soo Jay

    2015-04-01

    Recent study shows that tendon-sheath system (TSS) has great potential in the development of surgical robots for endoscopic surgery. It is able to deliver adequate power in a light-weight and compact package. And the flexibility and compliance of the tendon-sheath system make it capable of adapting to the long and winding path in the flexible endoscope. However, the main difficulties in precise control of such system fall on the nonlinearities of the system behavior and absence of necessary sensory feedback at the surgical end-effectors. Since accurate position control of the tool is a prerequisite for efficacy, safety and intuitive user-experience in robotic surgery, in this paper we propose a system modeling approach for motion compensation. Based on a bidirectional actuated system using two separate tendon-sheaths, motion transmission is firstly characterized. Two types of positional errors due to system backlash and environment loading are defined and modeled. Then a model-based feedforward compensation method is proposed for open-loop control, giving the system abilities to adjust according to changes in the transmission route configuration without any information feedback from the distal end. A dedicated experimental platform emulating a bidirectional TSS robotic system for endoscopic surgery is built for testing. Proposed positional errors are identified and verified. The performance of the proposed motion compensation is evaluated by trajectory tracking under different environment loading conditions. And the results demonstrate that accurate position control can be achieved even if the transmission route configuration is updated. PMID:25819033

  20. Dynamic fast terminal sliding mode control of a shape memory alloy actuated system

    NASA Astrophysics Data System (ADS)

    Marathe, Meeshawn S.; Srinivasan, S. M.

    2016-04-01

    In this paper we address the chattering phenomenon which is a common drawback associated with the normal Sliding Mode Control (SMC) law for a basic shape memory alloy (SMA) actuated system. A new method has been proposed to counter this effect by combining the concepts of Fast Terminal SMC and Dynamic controller. A phenomenological model is developed for the SMA which incorporates a piecewise linear hysteresis behavior. This model is used for both open loop as well as closed loop simulations for a linear motion control system. Based on this model, a dynamic terminal sliding mode control law is derived and applied to the system. A normal SMC law with saturation function which is known to reduce chattering is compared with the proposed control law for its effectiveness to curb the issue of chattering versus its ability to faithfully track a desired trajectory. Numerical Simulations indicate that the proposed law is able to reduce the chattering effect sufficiently and at par with the control technique involving saturation function.

  1. Observer-based reliable stabilization of uncertain linear systems subject to actuator faults, saturation, and bounded system disturbances.

    PubMed

    Fan, Jinhua; Zhang, Youmin; Zheng, Zhiqiang

    2013-11-01

    A matrix inequality approach is proposed to reliably stabilize a class of uncertain linear systems subject to actuator faults, saturation, and bounded system disturbances. The system states are assumed immeasurable, and a classical observer is incorporated for observation to enable state-based feedback control. Both the stability and stabilization of the closed-loop system are discussed and the closed-loop domain of attraction is estimated by an ellipsoidal invariant set. The resultant stabilization conditions in the form of matrix inequalities enable simultaneous optimization of both the observer gain and the feedback controller gain, which is realized by converting the non-convex optimization problem to an unconstrained nonlinear programming problem. The effectiveness of proposed design techniques is demonstrated through a linearized model of F-18 HARV around an operating point.

  2. Monolithic integrated system with an electrowetting-on-dielectric actuator and a film-bulk-acoustic-resonator sensor

    NASA Astrophysics Data System (ADS)

    Zhang, Menglun; Cui, Weiwei; Chen, Xuejiao; Wang, Chao; Pang, Wei; Duan, Xuexin; Zhang, Daihua; Zhang, Hao

    2015-02-01

    Although digital microfluidics has shown great potential in a wide range of applications, a lab-on-a-chip with integrated digital droplet actuators and powerful biochemical sensors is still lacking. To address the demand, a fully integrated chip with electrowetting-on-dielectric (EWOD) and a film bulk acoustic resonator (FBAR) sensor is introduced, where an EWOD actuator manipulates digital droplets and the FBAR sensor detects the presence of substances in the droplets, respectively. The piezoelectric layer of the FBAR sensor and the dielectric layer of the EWOD share the same aluminum nitride (AlN) thin film, which is a key factor to achieve the full integration of the two completely different devices. The liquid droplets are reliably managed by the EWOD actuator to sit on or move off the FBAR sensor precisely. Sessile drop experiments and limit of detection (LOD) experiments are carried out to characterize the EWOD actuator and the FBAR sensor, respectively. Taking advantage of the digital droplet operation, a ‘dry sensing mode’ of the FBAR sensor in the lab-on-a-chip microsystem is proposed, which has a much higher signal to noise ratio than the conventional ‘wet sensing mode’. Hg2+ droplets with various concentrations are transported and sensed to demonstrate the capability of the integrated system. The EWOD-FBAR chip is expected to play an important role in many complex lab-on-a-chip applications.

  3. Development of an Upper Limb Power Assist System Using Pneumatic Actuators for Farming Lift-up Motion

    NASA Astrophysics Data System (ADS)

    Yagi, Eiichi; Harada, Daisuke; Kobayashi, Masaaki

    A power assist system has lately attracted considerable attention to lifting-up an object without low back pain. We have been developing power assist systems with pneumatic actuators for the elbow and shoulder to farming support of lifting-up a bag of rice weighing 30kg. This paper describes the mechanism and control method of this power assist system. The pneumatic rotary actuator supports shoulder motion, and the air cylinder supports elbow motion. In this control method, the surface electromyogram(EMG) signals are used as input information of the controller. The joint support torques of human are calculated based on the antigravity term of necessary joint torques, which are estimated on the dynamics of a human approximated link model. The experimental results show the effectiveness of the proposed mechanism and control method of the power assist system.

  4. Electromechanical simulation and test of rotating systems with magnetic bearing or piezoelectric actuator active vibration control

    NASA Technical Reports Server (NTRS)

    Palazzolo, Alan B.; Tang, Punan; Kim, Chaesil; Manchala, Daniel; Barrett, Tim; Kascak, Albert F.; Brown, Gerald; Montague, Gerald; Dirusso, Eliseo; Klusman, Steve

    1994-01-01

    This paper contains a summary of the experience of the authors in the field of electromechanical modeling for rotating machinery - active vibration control. Piezoelectric and magnetic bearing actuator based control are discussed.

  5. Physical protection system design and evaluation

    SciTech Connect

    Williams, J.D.

    1997-03-01

    The design of an effective physical protection system includes the determination of physical protection system objectives, initial design of a physical protection system, design evaluation, and probably a redesign or refinement. To develop the objectives, the designer must begin by gathering information about facility operation and conditions, such as a comprehensive description of the facility, operating conditions, and the physical protection requirements. The designer then needs to define the threat. This involves considering factors about potential adversaries: class of adversary, adversary`s capabilities, and range of adversary`s tactics. Next, the designer should identify targets. Determination of whether or not the materials being protected are attractive targets is based mainly on the ease or difficulty of acquisition and desirability of the material. The designer now knows the objectives of the physical protection system, that is, {open_quotes}what to protect against whom.{close_quotes} The next step is to design the system by determining how best to combine such elements as fences, vaults, sensors and assessment devices, entry control elements, procedures, communication devices, and protective forces personnel to meet the objectives of the system. Once a physical protection system is designed, it must be analyzed and evaluated to ensure it meets the physical protection objectives. Evaluation must allow for features working together to ensure protection rather than regarding each feature separately. Due to the complexity of the protection systems, an evaluation usually requires modeling techniques. If any vulnerabilities are found, the initial system must be redesigned to correct the vulnerabilities and a reevaluation conducted. This paper reviews the physical protection system design and methodology mentioned above. Examples of the steps required and a brief introduction to some of the technologies used in modem physical protections system are given.

  6. Muscle Motion Solenoid Actuator

    NASA Astrophysics Data System (ADS)

    Obata, Shuji

    It is one of our dreams to mechanically recover the lost body for damaged humans. Realistic humanoid robots composed of such machines require muscle motion actuators controlled by all pulling actions. Particularly, antagonistic pairs of bi-articular muscles are very important in animal's motions. A system of actuators is proposed using the electromagnetic force of the solenoids with the abilities of the stroke length over 10 cm and the strength about 20 N, which are needed to move the real human arm. The devised actuators are based on developments of recent modern electro-magnetic materials, where old time materials can not give such possibility. Composite actuators are controlled by a high ability computer and software making genuine motions.

  7. High power thrust vector actuation

    NASA Astrophysics Data System (ADS)

    Kittock, M. J.

    1993-06-01

    Modern missile programs are frequently favoring electro-mechanical (EM) thrust vector actuation (TVA) over hydraulic for a variety of reasons. However, actuation system performance requirements are not relaxed for EM systems. Thus the development of EM systems with greater power output is required. The configuration of EM actuator studied consists of a DC brushless motor driving a spur gear train, which drives a ballscrew that converts rotary motion to rectilinear motion. This design produces an actuator with high levels of performance in a compact mechanical package. Design for manufacturability and assembly (DFMA) was part of the design process, resulting in an actuator that can be assembled easily and will operate reliably. This paper will discuss the mechanical details of the resultant actuator and report test results on a prototype derivative.

  8. Piezoelectrically Actuated Robotic System for MRI-Guided Prostate Percutaneous Therapy

    PubMed Central

    Su, Hao; Shang, Weijian; Cole, Gregory; Li, Gang; Harrington, Kevin; Camilo, Alexander; Tokuda, Junichi; Tempany, Clare M.; Hata, Nobuhiko; Fischer, Gregory S.

    2014-01-01

    This paper presents a fully-actuated robotic system for percutaneous prostate therapy under continuously acquired live magnetic resonance imaging (MRI) guidance. The system is composed of modular hardware and software to support the surgical workflow of intra-operative MRI-guided surgical procedures. We present the development of a 6-degree-of-freedom (DOF) needle placement robot for transperineal prostate interventions. The robot consists of a 3-DOF needle driver module and a 3-DOF Cartesian motion module. The needle driver provides needle cannula translation and rotation (2-DOF) and stylet translation (1-DOF). A custom robot controller consisting of multiple piezoelectric motor drivers provides precision closed-loop control of piezoelectric motors and enables simultaneous robot motion and MR imaging. The developed modular robot control interface software performs image-based registration, kinematics calculation, and exchanges robot commands and coordinates between the navigation software and the robot controller with a new implementation of the open network communication protocol OpenIGTLink. Comprehensive compatibility of the robot is evaluated inside a 3-Tesla MRI scanner using standard imaging sequences and the signal-to-noise ratio (SNR) loss is limited to 15%. The image deterioration due to the present and motion of robot demonstrates unobservable image interference. Twenty-five targeted needle placements inside gelatin phantoms utilizing an 18-gauge ceramic needle demonstrated 0.87 mm root mean square (RMS) error in 3D Euclidean distance based on MRI volume segmentation of the image-guided robotic needle placement procedure. PMID:26412962

  9. Characterization of electrode alignment for optimal droplet charging and actuation in droplet-based microfluidic system.

    PubMed

    Ahn, Myung Mo; Im, Do Jin; Yoo, Byeong Sun; Kang, In Seok

    2015-09-01

    The actuation method using electric force as a driving force is utilized widely in droplet-based microfluidic systems. In this work, the effects of charging electrode alignment on direct charging of a droplet on electrified electrodes and a subsequent electrophoretic control of the droplet are investigated. The charging characteristics of a droplet according to different electrode alignments are quantitatively examined through experiments and systematic numerical simulations with varying distances and angles between the two electrodes. The droplet charge acquired from the electrified electrode is directly proportional to the distance and barely affected by the angle between the two electrodes. This implies that the primary consideration of electrode alignment in microfluidic devices is the distance between electrodes and the insignificant effect of angle provides a great degree of freedom in designing such devices. Not only the droplet charge acquired from the electrode but also the force exerted on the droplet is analyzed. Finally, the implications and design guidance for microfluidic systems are discussed with an electrophoresis of a charged droplet method-based digital microfluidic device.

  10. Control of MEMS-based actuator array for micro smart systems

    NASA Astrophysics Data System (ADS)

    Chapuis, Yves-Andre; Fukuta, Yamato; Zhou, Lingfei; Mita, Yoshio; Fujita, Hiroyuki

    2005-02-01

    In the present work, the authors were focused on control modes used in distributed microsystems. Especially, they studied distributed manipulation like motion active surface that have been an important topic in micro and nanofabrication field. After comparing advantages and drawbacks between centralized, decentralized and distributed control systems, they decided to apply the control mode to an airflow active surface based on pneumatic microactuator array, and fabricated by MEMS technology. The size of the device is about 35x35 mm2 for 560 MEMS-based actuators and holes respectively at the front- and the back-side of the silicon substrate. In a first approach, and to overcome fabrication problems of the micro-smart system, combining electronic and electro mechanic elements, a co-design software/hardware solution was implemented. By this way, and using a digital image captured from a CCD camera, autonomy of the distributed microsystems could be developed. Afterward, a feedback control strategy was elaborated by applying principles of autonomous mobile robots that lend it to. A first prototype, validating all control mode principles was successfully implemented directly in software. Experiment results demonstrated advantages and good performances of the method.

  11. LHC magnet quench protection system

    NASA Astrophysics Data System (ADS)

    Coull, L.; Hagedorn, D.; Remondino, V.; Rodriguez-Mateos, F.

    1994-07-01

    The quench protection system for the superconducting magnets of the CERN Large Hadron Collider (LHC) is described. The system is based on the so called 'cold diode' concept. In a group of series connected magnets if one magnet quenches then the magnetic energy of all the magnets will be dissipated in the quenched magnet so destroying it. This is avoided by by-passing the quenched magnet and then rapidly de-exciting the unquenched magnets. For the LHC machine it is foreseen to use silicon diodes situated inside the cryostat as by-pass elements - so called 'cold diodes'. The diodes are exposed to some 50 kGray of radiation during a 10 year operation life-time. The high energy density of the LHC magnets (500 kJ/m) coupled with the relatively slow propagation speed of a 'natural' quench (10 to 20 m/s) can lead to excessive heating of the zone where the quench started and to high internal voltages. It is therefore necessary to detect quickly the incipient quench and fire strip heaters which spread the quench out more quickly over a large volume of the magnet. After a quench the magnet chain must be de-excited rapidly to avoid spreading the quench to other magnets and over-heating the by-pass diode. This is done by switching high-power energy-dump resistors in series with the magnets. The LHC main ring magnet will be divided into 16 electrically separated units which has important advantages.

  12. Development and Evaluation of an Actuated MRI-Compatible Robotic System for MRI-Guided Prostate Intervention

    PubMed Central

    Krieger, Axel; Song, Sang-Eun; Cho, Nathan B.; Iordachita, Iulian; Guion, Peter; Fichtinger, Gabor; Whitcomb, Louis L.

    2012-01-01

    This paper reports the design, development, and magnetic resonance imaging (MRI) compatibility evaluation of an actuated transrectal prostate robot for MRI-guided needle intervention in the prostate. The robot performs actuated needle MRI-guidance with the goals of providing (i) MRI compatibility, (ii) MRI-guided needle placement with accuracy sufficient for targeting clinically significant prostate cancer foci, (iii) reducing interventional procedure times (thus increasing patient comfort and reducing opportunity for needle targeting error due to patient motion), (iv) enabling real-time MRI monitoring of interventional procedures, and (v) reducing the opportunities for error that arise in manually actuated needle placement. The design of the robot, employing piezo-ceramic-motor actuated needle guide positioning and manual needle insertion, is reported. Results of a MRI compatibility study show no reduction of MRI signal-to-noise-ratio (SNR) with the motors disabled. Enabling the motors reduces the SNR by 80% without RF shielding, but SNR is only reduced by 40% to 60% with RF shielding. The addition of radio-frequency shielding is shown to significantly reduce image SNR degradation caused by the presence of the robotic device. An accuracy study of MRI-guided biopsy needle placements in a prostate phantom is reported. The study shows an average in-plane targeting error of 2.4 mm with a maximum error of 3.7 mm. These data indicate the system’s needle targeting accuracy is similar to that obtained with a previously reported manually actuated system, and is sufficient to reliably sample clinically significant prostate cancer foci under MRI-guidance. PMID:23326181

  13. Parametric resonance voltage response of electrostatically actuated Micro-Electro-Mechanical Systems cantilever resonators

    NASA Astrophysics Data System (ADS)

    Caruntu, Dumitru I.; Martinez, Israel; W. Knecht, Martin

    2016-02-01

    This paper investigates the parametric resonance voltage response of nonlinear parametrically actuated Micro-Electro-Mechanical Systems (MEMS) cantilever resonators. A soft AC voltage of frequency near natural frequency is applied between the resonator and a parallel ground plate. This produces an electrostatic force that leads the structure into parametric resonance. The model consists of an Euler-Bernoulli thin cantilever under the actuation of electrostatic force to include fringe effect, and damping force. Two methods of investigation are used, namely the Method of Multiple Scales (MMS) and Reduced Order Model (ROM) method. ROM convergence of the voltage response and the limitation of MMS to small to moderate amplitudes with respect to the gap (gap-amplitudes) are reported. MMS predicts accurately both Hopf supercritical and supercritical bifurcation voltages. However, MMS overestimates the large gap-amplitudes of the resonator, and. misses completely or overestimates the saddle-node bifurcation occurring at large gap-amplitudes. ROM produces valid results for small and/or large gap-amplitudes for a sufficient number of terms (vibration modes). As the voltage is swept up at constant frequency, the resonator maintains zero amplitude until reaches the subcritical Hopf bifurcation voltage where it loses stability and jumps up to large gap-amplitudes, next the gap-amplitude decreases until it reaches the supercritical Hopf bifurcation point, and after that the gap-amplitude remains zero, for the voltage range considered in this work. As the voltage is swept down at constant frequency, the zero gap-amplitude of the resonator starts increasing continuously after reaching the supercritical Hopf bifurcation voltage until it reaches the saddle-node bifurcation voltage when a sudden jump to zero gap-amplitude occurs. Effects of frequency, damping and fringe parameters on the voltage response show that (1) the supercritical Hopf bifurcation is shifted to lower voltage

  14. Piezoelectric Actuators On A Cold Finger

    NASA Technical Reports Server (NTRS)

    Kuo, Chin-Po; Garba, John A.; Glaser, Robert J.

    1995-01-01

    Developmental system for active suppression of vibrations of cold finger includes three piezoelectric actuators bonded to outer surface. Actuators used to suppress longitudinal and lateral vibrations of upper end of cold finger by applying opposing vibrations. Cold finger in question is part of a cryogenic system associated with an infrared imaging detector. When fully developed, system would be feedback sensor/control/actuator system automatically adapting to changing vibrational environment and suppresses pressure-induced vibrations by imposing compensatory vibrations via actuators.

  15. RIVER PROTECTION PROJECT SYSTEM PLAN

    SciTech Connect

    CERTA PJ

    2008-07-10

    The U.S. Department of Energy (DOE), Office of River Protection (ORP) manages the River Protection Project (RPP). The RPP mission is to retrieve and treat Hanford's tank waste and close the tank farms to protect the Columbia River. As a result, the ORP is responsible for the retrieval, treatment, and disposal of the approximately 57 million gallons of radioactive waste contained in the Hanford Site waste tanks and closure of all the tanks and associated facilities. The previous revision of the System Plan was issued in September 2003. ORP has approved a number of changes to the tank waste treatment strategy and plans since the last revision of this document, and additional changes are under consideration. The ORP has established contracts to implement this strategy to establish a basic capability to complete the overall mission. The current strategy for completion of the mission uses a number of interrelated activities. The ORP will reduce risk to the environment posed by tank wastes by: (1) Retrieving the waste from the single-shell tanks (SST) to double-shell tanks (DST) for treatment and disposal; (2) Constructing and operating the WTP, which will safely treat all of the high-level waste (HLW) and about half of the low-activity waste (LAW) contained in the tank farms, and maximizing its capability and capacity; (3) Developing and deploying supplemental treatment capability or a second WTP LAW Facility that can safely treat about half of the LAW contained in the tank farms; (4) Developing and deploying treatment and packaging capability for transuranic (TRU) tank waste for shipment to and disposal at the Waste Isolation Pilot Plant (WIPP); (5) Deploying interim storage capacity for the immobilized HLW and shipping that waste to Yucca Mountain for disposal; (6) Operating the Integrated Disposal Facility for the disposal of immobilized LAW, along with the associated secondary waste, (7) Closing the SST and DST tank farms, ancillary facilities, and al1 waste

  16. Actuation of polypyrrole nanowires

    NASA Astrophysics Data System (ADS)

    Lee, Alexander S.; Peteu, Serban F.; Ly, James V.; Requicha, Aristides A. G.; Thompson, Mark E.; Zhou, Chongwu

    2008-04-01

    Nanoscale actuators are essential components of the NEMS (nanoelectromechanical systems) and nanorobots of the future, and are expected to become a major area of development within nanotechnology. This paper demonstrates for the first time that individual polypyrrole (PPy) nanowires with diameters under 100 nm exhibit actuation behavior, and therefore can potentially be used for constructing nanoscale actuators. PPy is an electroactive polymer which can change volume on the basis of its oxidation state. PPy-based macroscale and microscale actuators have been demonstrated, but their nanoscale counterparts have not been realized until now. The research reported here answers positively the fundamental question of whether PPy wires still exhibit useful volume changes at the nanoscale. Nanowires with a 50 nm diameter and a length of approximately 6 µm, are fabricated by chemical polymerization using track-etched polycarbonate membranes as templates. Their actuation response as a function of oxidation state is investigated by electrochemical AFM (atomic force microscopy). An estimate of the minimum actuation force is made, based on the displacement of the AFM cantilever.

  17. Actuation of polypyrrole nanowires.

    PubMed

    Lee, Alexander S; Peteu, Serban F; Ly, James V; Requicha, Aristides A G; Thompson, Mark E; Zhou, Chongwu

    2008-04-23

    Nanoscale actuators are essential components of the NEMS (nanoelectromechanical systems) and nanorobots of the future, and are expected to become a major area of development within nanotechnology. This paper demonstrates for the first time that individual polypyrrole (PPy) nanowires with diameters under 100 nm exhibit actuation behavior, and therefore can potentially be used for constructing nanoscale actuators. PPy is an electroactive polymer which can change volume on the basis of its oxidation state. PPy-based macroscale and microscale actuators have been demonstrated, but their nanoscale counterparts have not been realized until now. The research reported here answers positively the fundamental question of whether PPy wires still exhibit useful volume changes at the nanoscale. Nanowires with a 50 nm diameter and a length of approximately 6 µm, are fabricated by chemical polymerization using track-etched polycarbonate membranes as templates. Their actuation response as a function of oxidation state is investigated by electrochemical AFM (atomic force microscopy). An estimate of the minimum actuation force is made, based on the displacement of the AFM cantilever.

  18. Air microjet system for non-contact force application and the actuation of micro-structures

    NASA Astrophysics Data System (ADS)

    Khare, S. M.; Venkataraman, V.

    2016-01-01

    We demonstrate a non-contact technique to apply calibrated and localized forces in the micro-Newton to milli-Newton range using an air microjet. An electromagnetically actuated diaphragm controlled by a signal generator is used to generate the air microjet. With a nozzle diameter of 150 μm, the microjet diameter was maintained to a maximum of 1 mm at a distance of 5 mm from the nozzle. The force generated by the microjet was measured using a commercial force sensor to determine the velocity profile of the jet. Axial flow velocities of up to 25 m s-1 were obtained at distances as long as 6 mm. The microjet exerted a force up to 1 μN on a poly dimethyl siloxane (PDMS) micropillar (50 μm in diameter, 157 μm in height) and 415 μN on a PDMS membrane (3 mm in diameter, 28 μm thick). We also demonstrate that from a distance of 6 mm our microjet can exert a peak pressure of 187 Pa with a total force of about 84 μN on a flat surface with 8 V operating voltage. Out of the cleanroom fabrication and robust design make this system cost effective and durable.

  19. Preventing Oxide Adhesion of Liquid Metal Alloys to Enable Actuation in Microfluidic Systems

    NASA Astrophysics Data System (ADS)

    Joshipura, Ishan; Johnson, Alexander; Ayers, Hudson; Dickey, Michael

    This work explores the wetting behavior of an oxide-coated liquid metal, eutectic alloy of gallium and indium (`EGaIn'), which remains a liquid at room temperature. Liquid metals uniquely combine fluidity with metallic properties. Combined, these properties enable soft, stretchable, and shape reconfigurable electronics with `softer than skin' interfaces. Ga forms spontaneously a thin surface oxide that alters its wetting behavior and makes it difficult to move across surfaces without leaving residue behind. We examine the effects of surface roughness (i.e., Cassie-Baxter state) and lubrication to minimize adhesion of Ga oxide to surfaces. Lubricated surfaces create a `slip-layer' of liquid between the metal and surface that also inhibits wetting. This slip layer allows the metal to move reversibly through microchannels by preventing adhesion of the oxide. The metal may be pumped or moved by using low voltages or pneumatic actuation. Optical microscopy confirms the importance of the slip-layer, which enables non-stick motion of the metal through capillaries. Finally, electrochemical impedance spectroscopy characterizes the electrohydrodynanic motion of EGaIn in capillary systems.

  20. Implantable control, telemetry, and solar energy system in the moving actuator type total artificial heart.

    PubMed

    Ahn, J M; Lee, J H; Choi, S W; Kim, W E; Omn, K S; Park, S K; Kim, W G; Roh, J R; Min, B G

    1998-03-01

    The moving actuator type total artificial heart (TAH) developed in the Seoul National University has numerous design improvements based upon the digital signal processor (DSP). These improvements include the implantability of all electronics, an automatic control algorithm, and extension of the battery run-time in connection with an amorphous silicon solar system (SS). The implantable electronics consist of the motor drive, main processor, intelligent Li ion battery management (LIBM) based upon the DSP, telemetry system, and transcutaneous energy transmission (TET) system. Major changes in the implantable electronics include decreasing the temperature rise by over 21 degrees C on the motor drive, volume reduction (40 x 55 x 33 mm, 7 cell assembly) of the battery pack using a Li ion (3.6 V/cell, 900 mA.h), and improvement of the battery run-time (over 40 min) while providing the cardiac output (CO) of 5 L/min at 100 mm Hg afterload when the external battery for testing is connected with the SS (2.5 W, 192.192, 1 kg) for the external battery recharge or the partial TAH drive. The phase locked loop (PLL) based telemetry system was implemented to improve stability and the error correction DSP algorithm programmed to achieve high accuracy. A field focused light emitting diode (LED) was used to obtain low light scattering along the propagation path, similar to the optical property of the laser and miniature sized, mounted on the pancake type TET coils. The TET operating resonance frequency was self tuned in a range of 360 to 410 kHz to provide enough power even at high afterloads. An automatic cardiac output regulation algorithm was developed based on interventricular pressure analysis and carried out in several animal experiments successfully. All electronics have been evaluated in vitro and in vivo and prepared for implantation of the TAH. Substantial progress has been made in designing a completely implantable TAH at the preclinical stage. PMID:9527287

  1. RIVER PROTECTION PROJECT SYSTEM PLAN

    SciTech Connect

    CERTA PJ; KIRKBRIDE RA; HOHL TM; EMPEY PA; WELLS MN

    2009-09-15

    The U.S. Department of Energy (DOE), Office of River Protection (ORP) manages the River Protection Project (RPP). The RPP mission is to retrieve and treat Hanford's tank waste and close the tank farms to protect the Columbia River. As a result, ORP is responsible for the retrieval, treatment, and disposal of approximately 57 million gallons 1 of radioactive waste contained in the Hanford Site waste tanks and closure2 of all the tanks and associated facilities. The previous revision of the System Plan was issued in May 2008. ORP has made a number of changes to the tank waste treatment strategy and plans since the last revision of this document, and additional changes are under consideration. ORP has contracts in place to implement the strategy for completion of the mission and establish the capability to complete the overall mission. The current strategl involves a number of interrelated activities. ORP will reduce risk to the environment posed by tank wastes by the following: (1) Retrieving the waste from the single-shell tanks (SST) to double-shell tanks (DST) and delivering the waste to the Waste Treatment and Immobilization Plant (WTP). (2) Constructing and operating the WTP, which will safely treat all of the high-level waste (HLW) fraction contained in the tank farms. About one-third of the low-activity waste (LAW) fraction separated from the HLW fraction in the WTP will be immobilized in the WTP LAW Vitrification Facility. (3) Developing and deploying supplemental treatment capability assumed to be a second LAW vitrification facility that can safely treat about two-thirds of the LAW contained in the tank farms. (4) Developing and deploying supplemental pretreatment capability currently assumed to be an Aluminum Removal Facility (ARF) using a lithium hydrotalcite process to mitigate sodium management issues. (5) Developing and deploying treatment and packaging capability for contact-handled transuranic (CH-TRU) tank waste for possible shipment to and disposal

  2. SRB/SLEEC (Solid Rocket Booster/Shingle Lap Extendible Exit Cone) feasibility study, volume 2. Appendix A: Design study for a SLEEC actuation system

    NASA Technical Reports Server (NTRS)

    Thompson, D. S.

    1986-01-01

    The results are presented of a design feasibility study of a self-contained (powered) actuation system for a Shingle Lap Extendible Exit Cone (SLEEC) for Transportation System (STS). The evolution of the SLEEC actuation system design is reviewed, the final design concept is summarized, and the results of the detailed study of the final concept of the actuation system are treated. A conservative design using proven mechanical components was established as a major program priority. The final mechanical design has a very low development risk since the components, which consist of ballscrews, gearing, flexible shaft drives, and aircraft cables, have extensive aerospace applications and a history of proven reliability. The mathematical model studies have shown that little or no power is required to deploy the SLEEC actuation system because acceleration forces and internal pressure from the rocket plume provide the required energies. A speed control brake is incorporated in the design in order to control the rate of deployment.

  3. Actuator selection for large space structures

    NASA Technical Reports Server (NTRS)

    Reddy, A. S. S. R.; Ruan, Mifang

    1990-01-01

    The paper discusses the process of selecting the actuator locations and the determination of the required number of actuators for large space structures. The selection is based on the definitions of the degree of controllability, the independence of actuators, and the effectiveness of the individual actuators. An algorithm is developed that can be used for the selection of the essential number of actuators and for finding some defects of the system, such as the insuffiency of the available actuator locations for effective control of the whole system or a too crowded frequency distribution. The efficiency of the algorithm was demonstrated by an application to the Space Station.

  4. Investigation of high frequency oscillations in the OV102 elevon actuation subsystems using continuous system modeling program simulation

    NASA Technical Reports Server (NTRS)

    Powell, W. W., Sr.

    1979-01-01

    Two theories emerged as the cause of undesired oscillations at frequencies between 40 and 60 Hz in the Orbiter Vehicle inboard and outboard elevon actuation subsystems during hardware testing. Both the "hardover feedback" and "deadspace" theories were examined using continuous system modeling program simulation. Results did not support the "hardover feedback" theory but showed that deadspace in the torque feedback spring connections to the servospools must be considered to be a possible cause of the oscillations. Further investigation is recommended.

  5. Thermal protection system and related methods

    NASA Technical Reports Server (NTRS)

    Garbe, Duane J. (Inventor)

    2012-01-01

    A thermal protection system and a method of manufacturing are disclosed. The thermal protection system may be configured to protect a movable joint, for example, a flexible bearing of a rocket motor nozzle. The thermal protection system includes a series of annular shims separated by a plurality of discrete spacers. Each shim of the series of annular shims may have a larger diameter than the previous shim, and the shims may nest. The shims may comprise a thermally stable material, and the discrete spacers may comprise an elastomer. Optionally, an annular bearing protector may separate the annular shims from the flexible bearing.

  6. A Combined Water-Bromotrifluoromethane Crash-Fire Protection System for a T-56 Turbopropeller Engine

    NASA Technical Reports Server (NTRS)

    Campbell, John A.; Busch, Arthur M.

    1959-01-01

    A crash-fire protection system is described which will suppress the ignition of crash-spilled fuel that may be ingested by a T-56 turbo-propeller engine. This system includes means for rapidly extinguishing the combustor flame, means for cooling and inerting with water the hot engine parts likely to ignite engine ingested fuel, and means for blanketing with bromotrifluoromethane massive metal parts that may reheat after the engine stops rotating. Combustion-chamber flames were rapidly extinguished at the engine fuel nozzles by a fuel shutoff and drain valve. Hot engine parts were inerted and cooled by 42 pounds of water discharged at seven engine stations. Massive metal parts that could reheat were inerted with 10 pounds of bromotrifluoromethane discharged at two engine stations. Performance trials of the crash-fire protection system were conducted by bringing the engine up to takeoff temperature, actuating the crash-fire protection system, and then spraying fuel into the engine to simulate crash-ingested fuel. No fires occurred during these trials, although fuel was sprayed into the engine from 0.3 second to 15 minutes after actuating the crash-fire protection system.

  7. Development of a 3-D Rehabilitation System for Upper Limbs Using ER Actuators in a Nedo Project

    NASA Astrophysics Data System (ADS)

    Furusho, Junji; Koyanagi, Ken'ichi; Nakanishi, Kazuhiko; Ryu, Ushio; Takenaka, Shigekazu; Inoue, Akio; Domen, Kazuhisa; Miyakoshi, Koichi

    New training methods and exercises for upper limbs rehabilitation are made possible by application of robotics and virtual reality technology. The technologies can also make quantitative evaluations and enhance the qualitative effect of training. We have joined a project managed by NEDO (New Energy and Industrial Technology Development Organization as a semi-governmental organization under the Ministry of Economy, Trade and Industry of Japan) 5-year Project, "Rehabilitation System for the Upper Limbs and Lower Limbs", and developed a 3-DOF exercise machine for upper limbs (EMUL) using ER actuators. In this paper, we also present the development of software for motion exercise trainings and some results of clinical evaluation. Moreover, it is discussed how ER actuators ensure the mechanical safety.

  8. Adaptive Fuzzy Tracking Control of Nonlinear Systems With Asymmetric Actuator Backlash Based on a New Smooth Inverse.

    PubMed

    Lai, Guanyu; Liu, Zhi; Zhang, Yun; Philip Chen, C L

    2016-06-01

    This paper is concentrated on the problem of adaptive fuzzy tracking control for an uncertain nonlinear system whose actuator is encountered by the asymmetric backlash behavior. First, we propose a new smooth inverse model which can approximate the asymmetric actuator backlash arbitrarily. By applying it, two adaptive fuzzy control scenarios, namely, the compensation-based control scheme and nonlinear decomposition-based control scheme, are then developed successively. It is worth noticing that the first fuzzy controller exhibits a better tracking control performance, although it recourses to a known slope ratio of backlash nonlinearity. The second one further removes the restriction, and also gets a desirable control performance. By the strict Lyapunov argument, both adaptive fuzzy controllers guarantee that the output tracking error is convergent to an adjustable region of zero asymptotically, while all the signals remain semiglobally uniformly ultimately bounded. Lastly, two comparative simulations are conducted to verify the effectiveness of the proposed fuzzy controllers. PMID:27187937

  9. Mixed H2/H∞ distributed robust model predictive control for polytopic uncertain systems subject to actuator saturation and missing measurements

    NASA Astrophysics Data System (ADS)

    Song, Yan; Fang, Xiaosheng; Diao, Qingda

    2016-03-01

    In this paper, we discuss the mixed H2/H∞ distributed robust model predictive control problem for polytopic uncertain systems subject to randomly occurring actuator saturation and packet loss. The global system is decomposed into several subsystems, and all the subsystems are connected by a fixed topology network, which is the definition for the packet loss among the subsystems. To better use the successfully transmitted information via Internet, both the phenomena of actuator saturation and packet loss resulting from the limitation of the communication bandwidth are taken into consideration. A novel distributed controller model is established to account for the actuator saturation and packet loss in a unified representation by using two sets of Bernoulli distributed white sequences with known conditional probabilities. With the nonlinear feedback control law represented by the convex hull of a group of linear feedback laws, the distributed controllers for subsystems are obtained by solving an linear matrix inequality (LMI) optimisation problem. Finally, numerical studies demonstrate the effectiveness of the proposed techniques.

  10. Actuating critical care therapeutics.

    PubMed

    Stone, David J; Csete, Marie

    2016-10-01

    Viewing the intensive care unit (ICU) as a control system with inputs (patients) and outputs (outcomes), we focus on actuation (therapies) of the system and how to enhance our understanding of status of patients and their trajectory in the ICU. To incorporate the results of these analytics meaningfully, we feel that a reassessment of predictive scoring systems and of ways to optimally characterize and display the patient's "state space" to clinicians is important. Advances in sensing (diagnostics) and computation have not yet led to significantly better actuation, and so we focus on ways that data can be used to improve actuation in the ICU, in particular by following therapeutic burden along with disease severity. This article is meant to encourage discussion about how the critical care community can best deal with the data they see each day, and prepare for recommendations that will inevitably arise from application of major federal and state initiatives in big data analytics and precision medicine.

  11. Propellant-powered actuator for gas generators

    NASA Technical Reports Server (NTRS)

    Makowski, M. J.

    1972-01-01

    Hydrazine operated monopropellant generators are used for spacecraft rocket engines and propellant pressurization systems. Measured work output of monopropellant actuators compares favorably with output of squib-type actuators.

  12. Outer skin protection of columbium Thermal Protection System (TPS) panels

    NASA Technical Reports Server (NTRS)

    Culp, J. D.

    1973-01-01

    A coated columbium alloy material system 0.04 centimeter thick was developed which provides for increased reliability to the load bearing character of the system in the event of physical damage to and loss of the exterior protective coating. The increased reliability to the load bearing columbium alloy (FS-85) was achieved by interposing an oxidation resistant columbium alloy (B-1) between the FS-85 alloy and a fused slurry silicide coating. The B-1 alloy was applied as a cladding to the FS-85 and the composite was fused slurry silicide coated. Results of material evaluation testing included cyclic oxidation testing of specimens with intentional coating defects, tensile testing of several material combinations exposed to reentry profile conditions, and emittance testing after cycling of up to 100 simulated reentries. The clad material, which was shown to provide greater reliability than unclad materials, holds significant promise for use in the thermal protection system of hypersonic reentry vehicles.

  13. Aging assessment for active fire protection systems

    SciTech Connect

    Ross, S.B.; Nowlen, S.P.; Tanaka, T.

    1995-06-01

    This study assessed the impact of aging on the performance and reliability of active fire protection systems including both fixed fire suppression and fixed fire detection systems. The experience base shows that most nuclear power plants have an aggressive maintenance and testing program and are finding degraded fire protection system components before a failure occurs. Also, from the data reviewed it is clear that the risk impact of fire protection system aging is low. However, it is assumed that a more aggressive maintenance and testing program involving preventive diagnostics may reduce the risk impact even further.

  14. Current Technology for Thermal Protection Systems

    NASA Technical Reports Server (NTRS)

    Scotti, Stephen J. (Compiler)

    1992-01-01

    Interest in thermal protection systems for high-speed vehicles is increasing because of the stringent requirements of such new projects as the Space Exploration Initiative, the National Aero-Space Plane, and the High-Speed Civil Transport, as well as the needs for improved capabilities in existing thermal protection systems in the Space Shuttle and in turbojet engines. This selection of 13 papers from NASA and industry summarizes the history and operational experience of thermal protection systems utilized in the national space program to date, and also covers recent development efforts in thermal insulation, refractory materials and coatings, actively cooled structures, and two-phase thermal control systems.

  15. Vct system having closed loop control employing spool valve actuated by a stepper motor

    SciTech Connect

    Quin, S.B. Jr.; Siemon, E.C.

    1993-06-15

    An internal combustion engine is described comprising: a crankshaft, the crankshaft being rotable about an axis; a cam shaft, the cam shaft being rotatable about a second axis, the second axis being parallel to the axis, the cam shaft being subject to torque reversals during the rotation thereof; a vane, the vane having at least one lobe, the vane being attached to the cam shaft, being rotatable with the cam shaft and being non-oscillatable with respect to the cam shaft; a housing, the housing being rotatable with the cam shaft and being oscillatable with respect to the cam shaft, the housing having at least one recess, the recess receiving the lobe, the lobe being oscillatable within the recess; rotary movement transmitting means for transmitting rotary movement from the crankshaft to the housing; actuating means for varying the position of the housing relative to the cam shaft in reaction to torque reversals in the cam shaft, the actuating means comprising a stepper motor, a lead screw and a proportional spool valve, the position of the spool valve being controlled by the position of the lead screw driven by the stepper motor, the actuating means also delivering hydraulic fluid to the vane; and processing means for controlling the position of the actuating means.

  16. Effect of Bending Stiffness of the Electroactive Polymer Element on the Performance of a Hybrid Actuator System (HYBAS)

    NASA Technical Reports Server (NTRS)

    Xu, Tian-Bing; Su, Ji; Jiang, Xiaoning; Rehrig, Paul W.; Zhang, Shujun; Shrout, Thomas R.; Zhang, Qiming

    2006-01-01

    An electroactive polymer (EAP)-ceramic hybrid actuation system (HYBAS) was developed recently at NASA Langley Research Center. This paper focuses on the effect of the bending stiffness of the EAP component on the performance of a HYBAS, in which the actuation of the EAP element can match the theoretical prediction at various length/thickness ratios for a constant elastic modulus of the EAP component. The effects on the bending stiffness of the elastic modulus and length/thickness ratio of the EAP component were studied. A critical bending stiffness to keep the actuation of the EAP element suitable for a rigid beam theory-based modeling was found for electron irradiated P(VDF-TrFE) copolymer. For example, the agreement of experimental data and theoretical modeling for a HYBAS with the length/thickness ratio of EAP element at 375 times is demonstrated. However, the beam based theoretical modeling becomes invalid (i.e., the profile of the HYBAS movement does not follow the prediction of theoretical modeling) when the bending stiffness is lower than a critical value.

  17. Actuated atomizer

    NASA Technical Reports Server (NTRS)

    Tilton, Charles (Inventor); Weiler, Jeff (Inventor); Palmer, Randall (Inventor); Appel, Philip (Inventor)

    2008-01-01

    An actuated atomizer is adapted for spray cooling or other applications wherein a well-developed, homogeneous and generally conical spray mist is required. The actuated atomizer includes an outer shell formed by an inner ring; an outer ring; an actuator insert and a cap. A nozzle framework is positioned within the actuator insert. A base of the nozzle framework defines swirl inlets, a swirl chamber and a swirl chamber. A nozzle insert defines a center inlet and feed ports. A spool is positioned within the coil housing, and carries the coil windings having a number of turns calculated to result in a magnetic field of sufficient strength to overcome the bias of the spring. A plunger moves in response to the magnetic field of the windings. A stop prevents the pintle from being withdrawn excessively. A pintle, positioned by the plunger, moves between first and second positions. In the first position, the head of the pintle blocks the discharge passage of the nozzle framework, thereby preventing the atomizer from discharging fluid. In the second position, the pintle is withdrawn from the swirl chamber, allowing the atomizer to release atomized fluid. A spring biases the pintle to block the discharge passage. The strength of the spring is overcome, however, by the magnetic field created by the windings positioned on the spool, which withdraws the plunger into the spool and further compresses the spring.

  18. Actuator mechanism

    NASA Technical Reports Server (NTRS)

    Stange, W. C. (Inventor)

    1978-01-01

    An actuator mechanism is described, having a frame with a rotatable shaft supported in the frame, a positioning mechanism coupled to the shaft for rotating the shaft in two rotary positions, disposed approximately 180 degrees apart, and a pair of plungers coupled to the shaft. Each plunger is responsive to a control signal for applying bi-directional rotation to the shaft.

  19. Requirements for CEC POP machine protection system

    SciTech Connect

    Pinayev, I.

    2015-02-18

    The requirements of CEC POP machine protection system are meant to prevent damage to a vacuum chamber by a missteered electron beam. In this example, beam energy = 22 MeV, Maximal bunch charge = 5 nC, Maximal repetition rate = 78 kHz, Normalized emittance = 5 mm mrad, Minimal β-function = 1 m. From this information the requirements of the protection system can be calculated by factoring the information into equations to find beam densities and temperature excursions.

  20. Space Shuttle Main Engine control system. [hydraulic actuator with digital control

    NASA Technical Reports Server (NTRS)

    Seitz, P. F.; Searle, R. F.

    1973-01-01

    The Space Shuttle Main Engine is a reusable, high-performance rocket engine being developed by the Rocketdyne Div. of Rockwell International to satisfy the operational requirements of the Space Shuttle Orbiter Vehicle. The design incorporates a hydraulically actuated, closed-loop servosystem controlled and monitored by a programmable electronic digital controller. The controller accepts vehicle commands for the various engine operational phases, positions the appropriate valves, monitors the engine for the required performance precisions and conditions, and provides redundancy management.

  1. Tool actuation and force feedback on robot-assisted microsurgery system

    NASA Technical Reports Server (NTRS)

    Das, Hari (Inventor); Ohm, Tim R. (Inventor); Boswell, Curtis D. (Inventor); Steele, Robert D. (Inventor)

    2002-01-01

    An input control device with force sensors is configured to sense hand movements of a surgeon performing a robot-assisted microsurgery. The sensed hand movements actuate a mechanically decoupled robot manipulator. A microsurgical manipulator, attached to the robot manipulator, is activated to move small objects and perform microsurgical tasks. A force-feedback element coupled to the robot manipulator and the input control device provides the input control device with an amplified sense of touch in the microsurgical manipulator.

  2. Performance of Optimized Actuator and Sensor Arrays in an Active Noise Control System

    NASA Technical Reports Server (NTRS)

    Palumbo, D. L.; Padula, S. L.; Lyle, K. H.; Cline, J. H.; Cabell, R. H.

    1996-01-01

    Experiments have been conducted in NASA Langley's Acoustics and Dynamics Laboratory to determine the effectiveness of optimized actuator/sensor architectures and controller algorithms for active control of harmonic interior noise. Tests were conducted in a large scale fuselage model - a composite cylinder which simulates a commuter class aircraft fuselage with three sections of trim panel and a floor. Using an optimization technique based on the component transfer functions, combinations of 4 out of 8 piezoceramic actuators and 8 out of 462 microphone locations were evaluated against predicted performance. A combinatorial optimization technique called tabu search was employed to select the optimum transducer arrays. Three test frequencies represent the cases of a strong acoustic and strong structural response, a weak acoustic and strong structural response and a strong acoustic and weak structural response. Noise reduction was obtained using a Time Averaged/Gradient Descent (TAGD) controller. Results indicate that the optimization technique successfully predicted best and worst case performance. An enhancement of the TAGD control algorithm was also evaluated. The principal components of the actuator/sensor transfer functions were used in the PC-TAGD controller. The principal components are shown to be independent of each other while providing control as effective as the standard TAGD.

  3. A Control Allocation System for Automatic Detection and Compensation of Phase Shift Due to Actuator Rate Limiting

    NASA Technical Reports Server (NTRS)

    Yildiz, Yidiray; Kolmanovsky, Ilya V.; Acosta, Diana

    2011-01-01

    This paper proposes a control allocation system that can detect and compensate the phase shift between the desired and the actual total control effort due to rate limiting of the actuators. Phase shifting is an important problem in control system applications since it effectively introduces a time delay which may destabilize the closed loop dynamics. A relevant example comes from flight control where aggressive pilot commands, high gain of the flight control system or some anomaly in the system may cause actuator rate limiting and effective time delay introduction. This time delay can instigate Pilot Induced Oscillations (PIO), which is an abnormal coupling between the pilot and the aircraft resulting in unintentional and undesired oscillations. The proposed control allocation system reduces the effective time delay by first detecting the phase shift and then minimizing it using constrained optimization techniques. Flight control simulation results for an unstable aircraft with inertial cross coupling are reported, which demonstrate phase shift minimization and recovery from a PIO event.

  4. R&D ERL: Machine Protection System

    SciTech Connect

    Altinbas, Z.

    2010-01-01

    The Machine Protection System (MPS) is a device-safety system that is designed to prevent damage to hardware by generating interlocks, based upon the state of input signals generated by selected sub-system. It exists to protect key machinery such as the 50 kW and 1 MW RF Systems. When a fault state occurs, the MPS is capable of responding with an interlock signal within several microseconds. The Machine Protection System inputs are designed to be fail-safe. In addition, all fault conditions are latched and time-stamped. The ERL MPS is based on a National Instruments hardware platform, and is programmed by utilizing National Instruments development environment for a visual programming language.

  5. Optimized actuators for ultrathin deformable primary mirrors.

    PubMed

    Laslandes, Marie; Patterson, Keith; Pellegrino, Sergio

    2015-05-20

    A novel design and selection scheme for surface-parallel actuators for ultrathin, lightweight mirrors is presented. The actuation system consists of electrodes printed on a continuous layer of piezoelectric material bonded to an optical-quality substrate. The electrodes provide almost full coverage of the piezoelectric layer, in order to maximize the amount of active material that is available for actuation, and their shape is optimized to maximize the correctability and stroke of the mirror for a chosen number of independent actuators and for a dominant imperfection mode. The starting point for the design of the electrodes is the observation that the correction of a figure error that has at least two planes of mirror symmetry is optimally done with twin actuators that have the same optimized shape but are rotated through a suitable angle. Additional sets of optimized twin actuators are defined by considering the intersection between the twin actuators, and hence an arbitrarily fine actuation pattern can be generated. It is shown that this approach leads to actuator systems with better performance than simple, geometrically based actuators. Several actuator patterns to correct third-order astigmatism aberrations are presented, and an experimental demonstration of a 41-actuator mirror is also presented. PMID:26192533

  6. Modular droplet actuator drive

    NASA Technical Reports Server (NTRS)

    Pollack, Michael G. (Inventor); Paik, Philip (Inventor)

    2011-01-01

    A droplet actuator drive including a detection apparatus for sensing a property of a droplet on a droplet actuator; circuitry for controlling the detection apparatus electronically coupled to the detection apparatus; a droplet actuator cartridge connector arranged so that when a droplet actuator cartridge electronically is coupled thereto: the droplet actuator cartridge is aligned with the detection apparatus; and the detection apparatus can sense the property of the droplet on a droplet actuator; circuitry for controlling a droplet actuator coupled to the droplet actuator connector; and the droplet actuator circuitry may be coupled to a processor.

  7. Ethical foundations of the radiological protection system.

    PubMed

    Cho, K W

    2016-06-01

    The International Commission on Radiological Protection (ICRP) has established Task Group 94 under Committee 4 to develop a report on the ethical foundations of the system of radiological protection. The aim of this report is to consolidate the basis of ICRP recommendations, to improve understanding of the system, and to provide a basis for communication on radiation risk and its perception. Through a series of workshops organised by the Commission in cooperation with the International Radiation Protection Association and its associate societies involving radiological protection professionals and specialists of ethics around the world, Task Group 94 has identified the key ethical and social values underpinning the system of radiological protection. The purpose of eliciting the ethical principles and values of the radiological protection system is not only to clarify the rationale for recommendations made by the Commission, but also to assist in discussions related to its practical implementation. A clear understanding of the ethical principles will help resolve dilemmas caused by potential conflicts in actions that might be considered, or decisions that must be made.

  8. Ethical foundations of the radiological protection system.

    PubMed

    Cho, K W

    2016-06-01

    The International Commission on Radiological Protection (ICRP) has established Task Group 94 under Committee 4 to develop a report on the ethical foundations of the system of radiological protection. The aim of this report is to consolidate the basis of ICRP recommendations, to improve understanding of the system, and to provide a basis for communication on radiation risk and its perception. Through a series of workshops organised by the Commission in cooperation with the International Radiation Protection Association and its associate societies involving radiological protection professionals and specialists of ethics around the world, Task Group 94 has identified the key ethical and social values underpinning the system of radiological protection. The purpose of eliciting the ethical principles and values of the radiological protection system is not only to clarify the rationale for recommendations made by the Commission, but also to assist in discussions related to its practical implementation. A clear understanding of the ethical principles will help resolve dilemmas caused by potential conflicts in actions that might be considered, or decisions that must be made. PMID:26980798

  9. Water cooling system using a piezoelectrically actuated flow pump for a medical headlight system

    NASA Astrophysics Data System (ADS)

    Pires, Rogério F.; Vatanabe, Sandro L.; de Oliveira, Amaury R.; Nakasone, Paulo H.; Silva, Emílio C.

    2007-04-01

    The microchips inside modern electronic equipment generate heat and demand, each day, the use of more advanced cooling techniques as water cooling systems, for instance. These systems combined with piezoelectric flow pumps present some advantages such as higher thermal capacity, lower noise generation and miniaturization potential. The present work aims at the development of a water cooling system based on a piezoelectric flow pump for a head light system based on LEDs. The cooling system development consists in design, manufacturing and experimental characterization steps. In the design step, computational models of the pump, as well as the heat exchanger were built to perform sensitivity studies using ANSYS finite element software. This allowed us to achieve desired flow and heat exchange rates by varying the frequency and amplitude of the applied voltage. Other activities included the design of the heat exchanger and the dissipation module. The experimental tests of the cooling system consisted in measuring the temperature difference between the heat exchanger inlet and outlet to evaluate its thermal cooling capacity for different values of the flow rate. Comparisons between numerical and experimental results were also made.

  10. Advanced Protection & Service Restoration for FREEDM Systems

    NASA Astrophysics Data System (ADS)

    Singh, Urvir

    A smart electric power distribution system (FREEDM system) that incorporates DERs (Distributed Energy Resources), SSTs (Solid State Transformers - that can limit the fault current to two times of the rated current) & RSC (Reliable & Secure Communication) capabilities has been studied in this work in order to develop its appropriate protection & service restoration techniques. First, a solution is proposed that can make conventional protective devices be able to provide effective protection for FREEDM systems. Results show that although this scheme can provide required protection but it can be quite slow. Using the FREEDM system's communication capabilities, a communication assisted Overcurrent (O/C) protection scheme is proposed & results show that by using communication (blocking signals) very fast operating times are achieved thereby, mitigating the problem of conventional O/C scheme. Using the FREEDM System's DGI (Distributed Grid Intelligence) capability, an automated FLISR (Fault Location, Isolation & Service Restoration) scheme is proposed that is based on the concept of 'software agents' & uses lesser data (than conventional centralized approaches). Test results illustrated that this scheme is able to provide a global optimal system reconfiguration for service restoration.

  11. Thermal protection system flight repair kit

    NASA Technical Reports Server (NTRS)

    1979-01-01

    A thermal protection system (TPS) flight repair kit required for use on a flight of the Space Transportation System is defined. A means of making TPS repairs in orbit by the crew via extravehicular activity is discussed. A cure in place ablator, a precured ablator (large area application), and packaging design (containers for mixing and dispensing) for the TPS are investigated.

  12. Racial Disparity in Minnesota's Child Protection System

    ERIC Educational Resources Information Center

    Johnson, Erik P.; Clark, Sonja; Donald, Matthew; Pedersen, Rachel; Pichotta, Catherine

    2007-01-01

    Minnesota has been recognized by several studies as a state with a significant amount of racial disparity in its child protection system. This study, using 2001 data from Minnesota's Social Services Information Service, was conducted to determine at which of the six decision points in Minnesota's child welfare system racial disparities are…

  13. Future Interoperability of Camp Protection Systems (FICAPS)

    NASA Astrophysics Data System (ADS)

    Caron, Sylvie; Gündisch, Rainer; Marchand, Alain; Stahl, Karl-Hermann

    2013-05-01

    The FICAPS Project has been established as a Project of the European Defence Agency based on an initiative of Germany and France. Goal of this Project was to derive Guidelines, which by a proper implementation in future developments improve Camp Protection Systems (CPS) by enabling and improving interoperability between Camp Protection Systems and its Equipments of different Nations involved in multinational missions. These Guidelines shall allow for: • Real-time information exchange between equipments and systems of different suppliers and nations (even via SatCom), • Quick and easy replacement of equipments (even of different Nations) at run-time in the field by means of plug and play capability, thus lowering the operational and logistic costs and making the system highly available, • Enhancement of system capabilities (open and modular systems) by adding new equipment with new capabilities (just plug-in, automatic adjustment of the HMI Human Machine Interface) without costly and time consuming validation and test on system level (validation and test can be done on Equipment level), Four scenarios have been identified to summarize the interoperability requirements from an operational viewpoint. To prove the definitions given in the Guideline Document, a French and a German Demonstration System, based on existing national assets, were realized. Demonstrations, showing the capabilities given by the defined interoperability requirements with respect to the operational scenarios, were performed. Demonstrations included remote control of a CPS by another CPS, remote sensor control (Electro-Optic/InfraRed EO/IR) and remote effector control. This capability can be applied to extend the protection area or to protect distant infrastructural assets Demonstrations have been performed. The required interoperability functionality was shown successfully. Even if the focus of the FICAPS project was on camp protection, the solution found is also appropriate for other

  14. Pointwise Stabilization of a Hybrid System and Optimal Location of Actuator

    SciTech Connect

    Ammari, Kais Saidi, Abdelkader

    2007-06-15

    We consider a pointwise stabilization problem for a model arising in the control of noise. We prove that we have exponential stability for the low frequencies but not for the high frequencies. Thus, we give an explicit polynomial decay estimation at high frequencies that is valid for regular initial data while clarifying that the behavior of the constant which intervenes in this estimation there, functions as the frequency of cut. We propose a numerical approximation of the model and study numerically the best location of the actuator at low frequencies.

  15. Phase lag deduced information in photo-thermal actuation for nano-mechanical systems characterization

    SciTech Connect

    Bijster, R. J. F. Vreugd, J. de; Sadeghian, H.

    2014-08-18

    In photo-thermal actuation, heat is added locally to a micro-cantilever by means of a laser. A fraction of the irradiation is absorbed, yielding thermal stresses and deformations in the structure. Harmonic modulation of the laser power causes the cantilever to oscillate. Moreover, a phase lag is introduced which is very sensitive to the spot location and the cantilever properties. This phase lag is theoretically predicted and experimentally verified. Combined with thermo-mechanical properties of the cantilever and its geometry, the location of the laser spot, the thermal diffusivity, and the layer thicknesses of the cantilever can be extracted.

  16. Plant Modernization with Digital Reactor Protection System Safety System Upgrades at US Nuclear Power Stations

    SciTech Connect

    Heckle, Wm. Lloyd; Bolian, Tricia W.

    2006-07-01

    As the current fleet of nuclear power plants in the US reaches 25+ years of operation, obsolescence is driving many utilities to implement upgrades to both their safety and non-safety-related Instrumentation and Control (I and C) Systems. Digital technology is the predominant replacement technology for these upgrades. Within the last 15 years, digital control systems have been deployed in non-safety- related control applications at many utilities. In addition, a few utilities have replaced small safety-related systems utilizing digital technology. These systems have shown digital technology to be robust, reliable and simpler to maintain. Based upon this success, acceptance of digital technology has gained momentum with both utilities and regulatory agencies. Today, in an effort to extend the operating lives of their nuclear stations and resolve obsolescence of critical components, utilities are now pursuing digital technology for replacement of their primary safety systems. AREVA is leading this effort in the United States with the first significant digital upgrade of a major safety system. AREVA has previously completed upgrades to safety-related control systems emergency diesel engine controls and governor control systems for a hydro station which serves as the emergency power source for a nuclear station. Currently, AREVA is implementing the replacement of both the Reactor Protection System (RPS) and the Engineered Safety Features Actuation System (ESFAS) on all three units at a US PWR site. (authors)

  17. System and method for controlling hydraulic pressure in electro-hydraulic valve actuation systems

    DOEpatents

    Brennan, Daniel G; Marriott, Craig D; Cowgill, Joel; Wiles, Matthew A; Patton, Kenneth James

    2014-09-23

    A control system for an engine includes a first lift control module and a second lift control module. The first lift control module increases lift of M valves of the engine to a predetermined valve lift during a period before disabling or re-enabling N valves of the engine. The second lift control module decreases the lift of the M valves to a desired valve lift during a period after enabling or re-enabling the N valves of the engine, wherein N and M are integers greater than or equal to one.

  18. Integrated lab-on-chip biosensing systems based on magnetic particle actuation--a comprehensive review.

    PubMed

    van Reenen, Alexander; de Jong, Arthur M; den Toonder, Jaap M J; Prins, Menno W J

    2014-06-21

    The demand for easy to use and cost effective medical technologies inspires scientists to develop innovative lab-on-chip technologies for point-of-care in vitro diagnostic testing. To fulfill medical needs, the tests should be rapid, sensitive, quantitative, and miniaturizable, and need to integrate all steps from sample-in to result-out. Here, we review the use of magnetic particles actuated by magnetic fields to perform the different process steps that are required for integrated lab-on-chip diagnostic assays. We discuss the use of magnetic particles to mix fluids, to capture specific analytes, to concentrate analytes, to transfer analytes from one solution to another, to label analytes, to perform stringency and washing steps, and to probe biophysical properties of the analytes, distinguishing methodologies with fluid flow and without fluid flow (stationary microfluidics). Our review focuses on efforts to combine and integrate different magnetically actuated assay steps, with the vision that it will become possible in the future to realize integrated lab-on-chip biosensing assays in which all assay process steps are controlled and optimized by magnetic forces.

  19. Memory metal actuator

    NASA Technical Reports Server (NTRS)

    Ruoff, C. F. (Inventor)

    1985-01-01

    A mechanical actuator can be constructed by employing a plurality of memory metal actuator elements in parallel to control the amount of actuating force. In order to facilitate direct control by digital control signals provided by a computer or the like, the actuating elements may vary in stiffness according to a binary relationship. The cooling or reset time of the actuator elements can be reduced by employing Peltier junction cooling assemblies in the actuator.

  20. Design and optimization of voice coil actuator for six degree of freedom active vibration isolation system using Halbach magnet array

    NASA Astrophysics Data System (ADS)

    Kim, MyeongHyeon; Kim, Hyunchang; Gweon, Dae-Gab

    2012-10-01

    This paper describes the design, modeling, optimization, and validation of an active vibration isolation system using a voice coil motor. The active vibration isolating method was constructed with a passive isolator and an active isolator. A spring was used for passive isolating; an actuator was used for active isolating. The proposed active vibration isolation system (AVIS) can isolate disturbances for many kinds of instruments. Until now, developed AVIS were able to isolate a six degree-of-freedom disturbance effectively. This paper proposes the realization of such a six degree-of-freedom active vibration isolation system that can work as a bench top device for precision measuring machines such as atomic force microscope, scanning probe microscope, etc.

  1. Design and optimization of voice coil actuator for six degree of freedom active vibration isolation system using Halbach magnet array.

    PubMed

    Kim, MyeongHyeon; Kim, Hyunchang; Gweon, Dae-Gab

    2012-10-01

    This paper describes the design, modeling, optimization, and validation of an active vibration isolation system using a voice coil motor. The active vibration isolating method was constructed with a passive isolator and an active isolator. A spring was used for passive isolating; an actuator was used for active isolating. The proposed active vibration isolation system (AVIS) can isolate disturbances for many kinds of instruments. Until now, developed AVIS were able to isolate a six degree-of-freedom disturbance effectively. This paper proposes the realization of such a six degree-of-freedom active vibration isolation system that can work as a bench top device for precision measuring machines such as atomic force microscope, scanning probe microscope, etc.

  2. Carbon nanotube actuators

    PubMed

    Baughman; Cui; Zakhidov; Iqbal; Barisci; Spinks; Wallace; Mazzoldi; De Rossi D; Rinzler; Jaschinski; Roth; Kertesz

    1999-05-21

    Electromechanical actuators based on sheets of single-walled carbon nanotubes were shown to generate higher stresses than natural muscle and higher strains than high-modulus ferroelectrics. Like natural muscles, the macroscopic actuators are assemblies of billions of individual nanoscale actuators. The actuation mechanism (quantum chemical-based expansion due to electrochemical double-layer charging) does not require ion intercalation, which limits the life and rate of faradaic conducting polymer actuators. Unlike conventional ferroelectric actuators, low operating voltages of a few volts generate large actuator strains. Predictions based on measurements suggest that actuators using optimized nanotube sheets may eventually provide substantially higher work densities per cycle than any previously known technology.

  3. Favorable locations for piezo actuators in plates with good control effectiveness and minimal change in system dynamics

    NASA Astrophysics Data System (ADS)

    Dhuri, K. D.; Seshu, P.

    2007-12-01

    Placement and sizing of piezo actuators is normally based on control effectiveness. However, retrofitting of piezoelectric actuators alters the inherent stiffness/mass properties of the parent structure. In rotating structures, the additional mass due to piezo patches contributes to the centrifugal stiffening force. The parent structure is originally designed to have a certain natural frequency spectrum in relation to the disturbance excitation. In the event of failure of the active system, the dynamics of the structure with piezos (now rendered passive) will therefore become significant. Thus it will be helpful to determine locations for mounting piezo patches based on minimal natural frequency change yet with good control authority. In this study, a finite element based procedure for plate structures is presented. Favorable locations for mounting piezos based on minimal natural frequency changes are iteratively evolved from an initial configuration wherein the whole plate is covered with piezos. A modal controllability approach has been used for finding piezo mounting locations from a good controllability perspective. The procedure is demonstrated for simply supported square, swept-back, circular and rotating rectangular plates considering the first four modes.

  4. Gear-Driven Turnbuckle Actuator

    NASA Technical Reports Server (NTRS)

    Rivera, Ricky N.

    2010-01-01

    This actuator design allows the extension and contraction of turnbuckle assemblies. It can be operated manually or remotely, and is extremely compact. It is ideal for turnbuckles that are hard to reach by conventional tools. The tool assembly design solves the problem of making accurate adjustments to the variable geometry guide vanes without having to remove and reinstall the actuator system back on the engine. The actuator does this easily by adjusting the length of the turnbuckles while they are still attached to the engine.

  5. Rate dependent direct inverse hysteresis compensation of piezoelectric micro-actuator used in dual-stage hard disk drive head positioning system.

    PubMed

    Rahman, Md Arifur; Al Mamun, Abdullah; Yao, Kui

    2015-08-01

    The head positioning servo system in hard disk drive is implemented nowadays using a dual-stage actuator—the primary stage consisting of a voice coil motor actuator providing long range motion and the secondary stage controlling the position of the read/write head with fine resolution. Piezoelectric micro-actuator made of lead zirconate titanate (PZT) has been a popular choice for the secondary stage. However, PZT micro-actuator exhibits hysteresis—an inherent nonlinear characteristic of piezoelectric material. The advantage expected from using the secondary micro-actuator is somewhat lost by the hysteresis of the micro-actuator that contributes to tracking error. Hysteresis nonlinearity adversely affects the performance and, if not compensated, may cause inaccuracy and oscillation in the response. Compensation of hysteresis is therefore an important aspect for designing head-positioning servo system. This paper presents a new rate dependent model of hysteresis along with rigorous analysis and identification of the model. Parameters of the model are found using particle swarm optimization. Direct inverse of the proposed rate-dependent generalized Prandtl-Ishlinskii model is used as the hysteresis compensator. Effectiveness of the overall solution is underscored through experimental results.

  6. Rate dependent direct inverse hysteresis compensation of piezoelectric micro-actuator used in dual-stage hard disk drive head positioning system

    NASA Astrophysics Data System (ADS)

    Rahman, Md. Arifur; Al Mamun, Abdullah; Yao, Kui

    2015-08-01

    The head positioning servo system in hard disk drive is implemented nowadays using a dual-stage actuator—the primary stage consisting of a voice coil motor actuator providing long range motion and the secondary stage controlling the position of the read/write head with fine resolution. Piezoelectric micro-actuator made of lead zirconate titanate (PZT) has been a popular choice for the secondary stage. However, PZT micro-actuator exhibits hysteresis—an inherent nonlinear characteristic of piezoelectric material. The advantage expected from using the secondary micro-actuator is somewhat lost by the hysteresis of the micro-actuator that contributes to tracking error. Hysteresis nonlinearity adversely affects the performance and, if not compensated, may cause inaccuracy and oscillation in the response. Compensation of hysteresis is therefore an important aspect for designing head-positioning servo system. This paper presents a new rate dependent model of hysteresis along with rigorous analysis and identification of the model. Parameters of the model are found using particle swarm optimization. Direct inverse of the proposed rate-dependent generalized Prandtl-Ishlinskii model is used as the hysteresis compensator. Effectiveness of the overall solution is underscored through experimental results.

  7. Rate dependent direct inverse hysteresis compensation of piezoelectric micro-actuator used in dual-stage hard disk drive head positioning system.

    PubMed

    Rahman, Md Arifur; Al Mamun, Abdullah; Yao, Kui

    2015-08-01

    The head positioning servo system in hard disk drive is implemented nowadays using a dual-stage actuator—the primary stage consisting of a voice coil motor actuator providing long range motion and the secondary stage controlling the position of the read/write head with fine resolution. Piezoelectric micro-actuator made of lead zirconate titanate (PZT) has been a popular choice for the secondary stage. However, PZT micro-actuator exhibits hysteresis—an inherent nonlinear characteristic of piezoelectric material. The advantage expected from using the secondary micro-actuator is somewhat lost by the hysteresis of the micro-actuator that contributes to tracking error. Hysteresis nonlinearity adversely affects the performance and, if not compensated, may cause inaccuracy and oscillation in the response. Compensation of hysteresis is therefore an important aspect for designing head-positioning servo system. This paper presents a new rate dependent model of hysteresis along with rigorous analysis and identification of the model. Parameters of the model are found using particle swarm optimization. Direct inverse of the proposed rate-dependent generalized Prandtl-Ishlinskii model is used as the hysteresis compensator. Effectiveness of the overall solution is underscored through experimental results. PMID:26329224

  8. T-Slide Linear Actuators

    NASA Technical Reports Server (NTRS)

    Vranish, John

    2009-01-01

    T-slide linear actuators use gear bearing differential epicyclical transmissions (GBDETs) to directly drive a linear rack, which, in turn, performs the actuation. Conventional systems use a rotary power source in conjunction with a nut and screw to provide linear motion. Non-back-drive properties of GBDETs make the new actuator more direct and simpler. Versions of this approach will serve as a long-stroke, ultra-precision, position actuator for NASA science instruments, and as a rugged, linear actuator for NASA deployment duties. The T slide can operate effectively in the presence of side forces and torques. Versions of the actuator can perform ultra-precision positioning. A basic T-slide actuator is a long-stroke, rack-and-pinion linear actuator that, typically, consists of a T-slide, several idlers, a transmission to drive the slide (powered by an electric motor) and a housing that holds the entire assembly. The actuator is driven by gear action on its top surface, and is guided and constrained by gear-bearing idlers on its other two parallel surfaces. The geometry, implemented with gear-bearing technology, is particularly effective. An electronic motor operating through a GBDET can directly drive the T slide against large loads, as a rack and pinion linear actuator, with no break and no danger of back driving. The actuator drives the slide into position and stops. The slide holes position with power off and no brake, regardless of load. With the T slide configuration, this GBDET has an entire T-gear surface on which to operate. The GB idlers coupling the other two T slide parallel surfaces to their housing counterpart surfaces provide constraints in five degrees-of-freedom and rolling friction in the direction of actuation. Multiple GB idlers provide roller bearing strength sufficient to support efficient, rolling friction movement, even in the presence of large, resisting forces. T-slide actuators can be controlled using the combination of an off

  9. Electrical Actuation Technology Bridging

    NASA Technical Reports Server (NTRS)

    Hammond, Monica (Compiler); Sharkey, John (Compiler)

    1993-01-01

    This document contains the proceedings of the NASA Electrical Actuation Technology Bridging (ELA-TB) Workshop held in Huntsville, Alabama, September 29-October 1, 1992. The workshop was sponsored by the NASA Office of Space Systems Development and Marshall Space Flight Center (MSFC). The workshop addressed key technologies bridging the entire field of electrical actuation including systems methodology, control electronics, power source systems, reliability, maintainability, and vehicle health management with special emphasis on thrust vector control (TVC) applications on NASA launch vehicles. Speakers were drawn primarily from industry with participation from universities and government. In addition, prototype hardware demonstrations were held at the MSFC Propulsion Laboratory each afternoon. Splinter sessions held on the final day afforded the opportunity to discuss key issues and to provide overall recommendations. Presentations are included in this document.

  10. Evolution of thiol protective systems in prokaryotes

    NASA Technical Reports Server (NTRS)

    Fahey, R. C.; Newton, G. L.

    1986-01-01

    Biological thiols are essential elements in most aspects of cell function but undergo rapid oxidation to disulfides in the presence of oxygen. The evolution of systems to protect against such oxygen toxicity was essential to the emergence of aerobic life. The protection system used by eukaryotes is based upon glutathione (GSH) and GSH-dependent enzymes but many bacteria lack GSH and apparently use other mechanisms. The objective of this research is to elaborate the thiol protective mechanisms employed by prokaryotes of widely divergent evolutionary origin and to understand why GSH became the central thiol employed in essentially all higher organisms. Thiol-selective fluorescent labeling and HPLC analysis has been used to determine key monothiol components.

  11. Thermal Protection System with Staggered Joints

    NASA Technical Reports Server (NTRS)

    Simon, Xavier D. (Inventor); Robinson, Michael J. (Inventor); Andrews, Thomas L. (Inventor)

    2014-01-01

    The thermal protection system disclosed herein is suitable for use with a spacecraft such as a reentry module or vehicle, where the spacecraft has a convex surface to be protected. An embodiment of the thermal protection system includes a plurality of heat resistant panels, each having an outer surface configured for exposure to atmosphere, an inner surface opposite the outer surface and configured for attachment to the convex surface of the spacecraft, and a joint edge defined between the outer surface and the inner surface. The joint edges of adjacent ones of the heat resistant panels are configured to mate with each other to form staggered joints that run between the peak of the convex surface and the base section of the convex surface.

  12. Light-Driven Polymeric Bimorph Actuators

    NASA Technical Reports Server (NTRS)

    Adamovsky, Gregory; Sarkisov, Sergey S.; Curley, Michael J.

    2009-01-01

    Light-driven polymeric bimorph actuators are being developed as alternatives to prior electrically and optically driven actuators in advanced, highly miniaturized devices and systems exemplified by microelectromechanical systems (MEMS), micro-electro-optical-mechanical systems (MEOMS), and sensor and actuator arrays in smart structures. These light-driven polymeric bimorph actuators are intended to satisfy a need for actuators that (1) in comparison with the prior actuators, are simpler and less power-hungry; (2) can be driven by low-power visible or mid-infrared light delivered through conventional optic fibers; and (3) are suitable for integration with optical sensors and multiple actuators of the same or different type. The immediate predecessors of the present light-driven polymeric bimorph actuators are bimorph actuators that exploit a photorestrictive effect in lead lanthanum zirconate titanate (PLZT) ceramics. The disadvantages of the PLZT-based actuators are that (1) it is difficult to shape the PLZT ceramics, which are hard and brittle; (2) for actuation, it is necessary to use ultraviolet light (wavelengths < 380 nm), which must be generated by use of high-power, high-pressure arc lamps or lasers; (3) it is difficult to deliver sufficient ultraviolet light through conventional optical fibers because of significant losses in the fibers; (4) the response times of the PLZT actuators are of the order of several seconds unacceptably long for typical applications; and (5) the maximum mechanical displacements of the PLZT-based actuators are limited to those characterized by low strains beyond which PLZT ceramics disintegrate because of their brittleness. The basic element of a light-driven bimorph actuator of the present developmental type is a cantilever beam comprising two layers, at least one of which is a polymer that exhibits a photomechanical effect (see figure). The dominant mechanism of the photomechanical effect is a photothermal one: absorption of

  13. A Reconfiguration Scheme for Accommodating Actuator Failures in Multi-Input, Multi-Output Flight Control Systems

    NASA Technical Reports Server (NTRS)

    Siwakosit, W.; Hess, R. A.; Bacon, Bart (Technical Monitor); Burken, John (Technical Monitor)

    2000-01-01

    A multi-input, multi-output reconfigurable flight control system design utilizing a robust controller and an adaptive filter is presented. The robust control design consists of a reduced-order, linear dynamic inversion controller with an outer-loop compensation matrix derived from Quantitative Feedback Theory (QFT). A principle feature of the scheme is placement of the adaptive filter in series with the QFT compensator thus exploiting the inherent robustness of the nominal flight control system in the presence of plant uncertainties. An example of the scheme is presented in a pilot-in-the-loop computer simulation using a simplified model of the lateral-directional dynamics of the NASA F18 High Angle of Attack Research Vehicle (HARV) that included nonlinear anti-wind up logic and actuator limitations. Prediction of handling qualities and pilot-induced oscillation tendencies in the presence of these nonlinearities is included in the example.

  14. Prevention and the Child Protection System

    ERIC Educational Resources Information Center

    Waldfogel, Jane

    2009-01-01

    The nation's child protection system (CPS) has historically focused on preventing maltreatment in high-risk families, whose children have already been maltreated. But, as Jane Waldfogel explains, it has also begun developing prevention procedures for children at lower risk--those who are referred to CPS but whose cases do not meet the criteria for…

  15. Structural Sizing Methodology for the Tendon-Actuated Lightweight In-Space MANipulator (TALISMAN) System

    NASA Technical Reports Server (NTRS)

    Jones, Thomas C.; Dorsey, John T.; Doggett, William R.

    2015-01-01

    The Tendon-Actuated Lightweight In-Space MANipulator (TALISMAN) is a versatile long-reach robotic manipulator that is currently being tested at NASA Langley Research Center. TALISMAN is designed to be highly mass-efficient and multi-mission capable, with applications including asteroid retrieval and manipulation, in-space servicing, and astronaut and payload positioning. The manipulator uses a modular, periodic, tension-compression design that lends itself well to analytical modeling. Given the versatility of application for TALISMAN, a structural sizing methodology was developed that could rapidly assess mass and configuration sensitivities for any specified operating work space, applied loads and mission requirements. This methodology allows the systematic sizing of the key structural members of TALISMAN, which include the truss arm links, the spreaders and the tension elements. This paper summarizes the detailed analytical derivations and methodology that support the structural sizing approach and provides results from some recent TALISMAN designs developed for current and proposed mission architectures.

  16. Microelectromechanical Systems (MEMS) Actuator-Based, Polarization Reconfigurable Patch Antenna Demonstrated

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.

    2002-01-01

    A nearly square patch antenna with a contact actuator along a radiating edge for polarization reconfiguration was demonstrated at Ka-band frequencies at the NASA Glenn Research Center. The layout of the antenna is shown in the following sketch. This antenna has the following advantages: 1) It can be dynamically reconfigured to receive and transmit a linearly polarized signal or a circularly polarized signal. This feature allows the substitution of multiple antennas on a satellite by a single antenna, thereby resulting in significant cost savings. 2) In our approach, the polarization is switched between the two states without affecting the frequency of operation; thus, valuable frequency spectrum is conserved. 3) The ability to switch polarization also helps mitigate propagation effects due to adverse weather on the performance of a satellite-to-ground link. Hence, polarization reconfigurability enhances link reliability.

  17. Fluidic self-actuating control assembly

    DOEpatents

    Grantz, Alan L.

    1979-01-01

    A fluidic self-actuating control assembly for use in a reactor wherein no external control inputs are required to actuate (scram) the system. The assembly is constructed to scram upon sensing either a sudden depressurization of reactor inlet flow or a sudden increase in core neutron flux. A fluidic control system senses abnormal flow or neutron flux transients and actuates the system, whereupon assembly coolant flow reverses, forcing absorber balls into the reactor core region.

  18. Design of high performance piezo composites actuators

    NASA Astrophysics Data System (ADS)

    Almajid, Abdulhakim A.

    Design of high performance piezo composites actuators are developed. Functionally Graded Microstructure (FGM) piezoelectric actuators are designed to reduce the stress concentration at the middle interface existed in the standard bimorph actuators while maintaining high actuation performance. The FGM piezoelectric laminates are composite materials with electroelastic properties varied through the laminate thickness. The elastic behavior of piezo-laminates actuators is developed using a 2D-elasticity model and a modified classical lamination theory (CLT). The stresses and out-of-plane displacements are obtained for standard and FGM piezoelectric bimorph plates under cylindrical bending generated by an electric field throughout the thickness of the laminate. The analytical model is developed for two different actuator geometries, a rectangular plate actuator and a disk shape actuator. The limitations of CLT are investigated against the 2D-elasticity model for the rectangular plate geometry. The analytical models based on CLT (rectangular and circular) and 2D-elasticity are compared with a model based on Finite Element Method (FEM). The experimental study consists of two FGM actuator systems, the PZT/PZT FGM system and the porous FGM system. The electroelastic properties of each layer in the FGM systems were measured and input in the analytical models to predict the FGM actuator performance. The performance of the FGM actuator is optimized by manipulating the thickness of each layer in the FGM system. The thickness of each layer in the FGM system is made to vary in a linear or non-linear manner to achieve the best performance of the FGM piezoelectric actuator. The analytical and FEM results are found to agree well with the experimental measurements for both rectangular and disk actuators. CLT solutions are found to coincide well with the elasticity solutions for high aspect ratios while the CLT solutions gave poor results compared to the 2D elasticity solutions for

  19. Biomimetic actuator

    NASA Astrophysics Data System (ADS)

    Bouda, Vaclav; Boudova, Lea; Haluzikova, Denisa

    2005-05-01

    The aim of the presentation is to propose an alternative model of mammalian skeletal muscle function, which reflects the simplicity of nature and can be applied in engineering. Van der Waals attractive and repulsive electrostatic forces are assumed to control the design of internal structures and functions of contractile units of the muscles - sarcomere. The role of myosin heads is crucial for the higher order formation. The model of the myosin head lattice is the working model for the sarcomere contraction interpretation. The contraction is interpreted as a calcium induced phase transition of the lattice, which results in relative actin-myosin sliding and/or force generation. The model should provide the engineering science with a simple analogy to technical actuators of high performance.

  20. CLASSIFICATION OF THE MGR FIRE PROTECTION SYSTEM

    SciTech Connect

    R. Garrett

    1999-08-31

    The purpose of this analysis is to document the Quality Assurance (QA) classification of the Monitored Geologic Repository (MGR) subsurface fire protection system structures, systems and components (SSCs) performed by the MGR Safety Assurance Department. This analysis also provides the basis for revision of YMP/90-55Q, Q-List (YMP 1998). The Q-List identifies those MGR SSCs subject to the requirements of DOE/RW-0333P, ''Quality Assurance Requirements and Description'' (QARD) (DOE 1998).

  1. Reusable thermal protection system development: A prospective

    NASA Technical Reports Server (NTRS)

    Goldstein, Howard

    1992-01-01

    The state of the art in passive reusable thermal protection system materials is described. Development of the Space Shuttle Orbiter, which was the first reusable vehicle, is discussed. The thermal protection materials and given concepts and some of the shuttle development and manufacturing problems are described. Evolution of a family of grid and flexible ceramic external insulation materials from the initial shuttle concept in the early 1970's to the present time is described. The important properties and their evolution are documented. Application of these materials to vehicles currently being developed and plans for research to meet the space programs future needs are summarized.

  2. Development of a micro-step voltage-fed actuator with a novel stepper motor for automobile AGS systems.

    PubMed

    Rhyu, Se-Hyun; Lee, Jeong-Jong; Gu, Bon-Gwan; Choi, Byung-Dae; Lim, Jung-Hyuk

    2014-05-05

    This paper presents an improved micro-step voltage-fed actuator for an automobile active grill shutter (AGS) system. A novel structured stepper motor, which contains both the main and auxiliary teeth in the stator, is proposed for the actuator. In a normal permanent magnet (PM) motor coils are generally wound on all the stator teeth, however, in the proposed motor, the winding is only on the main teeth. Because of the absence of coils in the auxiliary teeth, the proposed stepper motor possesses the following advantages: simple structure, lighter weight, smaller volume, and less time consumption. The unique auxiliary poles in the stepper motor supply the flux path to increase the step resolution even without any coils. The characteristics of the proposed stepper motor were investigated using finite element analysis. In particular, the effect of the magnetization distribution of the PM on the motor performance was investigated during the analysis. Cogging torque, which causes noise and vibration issues, was minimized by the tooth-shape optimization. In addition, a micro-step voltage-fed algorithm was implemented for a high-resolution position control. By employing a current close to a sine wave using space vector pulse-width modulation, a high-quality current waveform with a high resolution was obtained. Finally, the proposed prototype was fabricated, and the cogging torque, back-electromotive force, and current characteristics were measured by mounting the prototype on the AGS system. Both the analysis and experimental results validate the performance improvement from the proposed motor and its possible application for the flap control of the AGS system.

  3. Thermal protection systems for hypersonic transport vehicles

    NASA Astrophysics Data System (ADS)

    Reich, G.; Hinger, J.; Huchler, M.

    1990-07-01

    Thermal protection systems (TPS) for hypersonic transport vehicles are described and evaluated. During the flight through the atmosphere moderate to high aerodynamic heating rates with corresponding high surface temperatures are generated. Therefore, a reliable light-weight but effective TPS is required, that limits the heat transfer into the central fuselage with the liquid hydrogen tank and that prevents the penetration of the temperature peak during stage separation to the load carrying structure. The heat transfer modes in the insulation are solid conduction, gas convection and radiation. Thermal protection systems based on different phenomena to reduce the heat transfer, like vacuum shingles, inert gas filled shingles, microporous insulations and multiwall structures, are described. It is demonstrated that microporous and multiwall insulations are efficient, light weight and reliable TPSs for future hypersonic transportation systems.

  4. Fire protection countermeasures for containment ventilation systems

    SciTech Connect

    Alvares, N.J.; Beason, D.G.; Bergman, W.; Ford, H.W.; Lipska, A.E.

    1980-01-01

    The goal of this project is to find countermeasures to protect HEPA filters in exit ventilation ducts from the heat and smoke generated by fire. Several methods for partially mitigating the smoke exposure to the HEPA filters were identified through testing and analysis. These independently involve controlling the fuel, controlling the fire, and intercepting the smoke aerosol prior to its sorption on the HEPA filter. Exit duct treatment of aerosols is not unusual in industrial applications and involves the use of scrubbers, prefilters, and inertial impaction, depending on the size, distribution, and concentration of the subject aerosol. However, when these unmodified techniques were applied to smoke aerosols from fires on materials, common to experimental laboratories of LLNL, it was found they offered minimal protection to the HEPA filters. Ultimately, a continuous, movable, high-efficiency prefilter using modified commercial equipment was designed. This technique is capable of protecting HEPA filters over the total duration of the test fires. The reason for success involved the modificaton of the prefiltration media. Commercially available filter media has a particle sorption efficiency that is inversely proportional to media strength. To achieve properties of both efficiency and strength, we laminated rolling filter media with the desired properties. It is not true that the use of rolling prefilters solely to protect HEPA filters from fire-generated smoke aerosols is cost effective in every type of containment system, especially if standard fire-protection systems are available in the space. But in areas of high fire risk, where the potential fuel load is large and ignition sources are plentiful, the complication of a rolling prefilter in exit ventilation ducts to protect HEPA filters from smoke aerosols is definitely justified.

  5. Development of a 3D parallel mechanism robot arm with three vertical-axial pneumatic actuators combined with a stereo vision system.

    PubMed

    Chiang, Mao-Hsiung; Lin, Hao-Ting

    2011-01-01

    This study aimed to develop a novel 3D parallel mechanism robot driven by three vertical-axial pneumatic actuators with a stereo vision system for path tracking control. The mechanical system and the control system are the primary novel parts for developing a 3D parallel mechanism robot. In the mechanical system, a 3D parallel mechanism robot contains three serial chains, a fixed base, a movable platform and a pneumatic servo system. The parallel mechanism are designed and analyzed first for realizing a 3D motion in the X-Y-Z coordinate system of the robot's end-effector. The inverse kinematics and the forward kinematics of the parallel mechanism robot are investigated by using the Denavit-Hartenberg notation (D-H notation) coordinate system. The pneumatic actuators in the three vertical motion axes are modeled. In the control system, the Fourier series-based adaptive sliding-mode controller with H(∞) tracking performance is used to design the path tracking controllers of the three vertical servo pneumatic actuators for realizing 3D path tracking control of the end-effector. Three optical linear scales are used to measure the position of the three pneumatic actuators. The 3D position of the end-effector is then calculated from the measuring position of the three pneumatic actuators by means of the kinematics. However, the calculated 3D position of the end-effector cannot consider the manufacturing and assembly tolerance of the joints and the parallel mechanism so that errors between the actual position and the calculated 3D position of the end-effector exist. In order to improve this situation, sensor collaboration is developed in this paper. A stereo vision system is used to collaborate with the three position sensors of the pneumatic actuators. The stereo vision system combining two CCD serves to measure the actual 3D position of the end-effector and calibrate the error between the actual and the calculated 3D position of the end-effector. Furthermore, to

  6. Protective autoimmunity in the nervous system.

    PubMed

    Graber, Jerome J; Dhib-Jalbut, Suhayl

    2009-02-01

    The immune system can play both detrimental and beneficial roles in the nervous system. Multiple arms of the immune system, including T cells, B cells, NK cells, mast cells, macrophages, dendritic cells, microglia, antibodies, complement and cytokines participate in limiting damage to the nervous system during toxic, ischemic, hemorrhagic, infective, degenerative, metabolic and immune-mediated insults and also assist in the process of repair after injury has occurred. Immune cells have been shown to produce neurotrophic growth factors and interact with neurons and glial cells to preserve them from injury and stimulate growth and repair. The immune system also appears to participate in proliferation of neural progenitor stem cells and their migration to sites of injury. Neural stem cells can also modify the immune response in the central and peripheral nervous system to enhance neuroprotective effects. Evidence for protective and reparative functions of the immune system has been found in diverse neurologic diseases including traumatic injury, ischemic and hemorrhagic stroke, multiple sclerosis, infection, and neurodegenerative diseases (Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis). Existing therapies including glatiramer acetate, interferon-beta and immunoglobulin have been shown to augment the protective and regenerative aspects of the immune system in humans, and other experimental interventions such as vaccination, minocycline, antibodies and neural stem cells, have shown promise in animal models of disease. The beneficent aspects of the immune response in the nervous system are beginning to be appreciated and their potential as pharmacologic targets in neurologic disease is being explored. PMID:19000712

  7. Apu/hydraulic/actuator Subsystem Computer Simulation. Space Shuttle Engineering and Operation Support, Engineering Systems Analysis. [for the space shuttle

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Major developments are examined which have taken place to date in the analysis of the power and energy demands on the APU/Hydraulic/Actuator Subsystem for space shuttle during the entry-to-touchdown (not including rollout) flight regime. These developments are given in the form of two subroutines which were written for use with the Space Shuttle Functional Simulator. The first subroutine calculates the power and energy demand on each of the three hydraulic systems due to control surface (inboard/outboard elevons, rudder, speedbrake, and body flap) activity. The second subroutine incorporates the R. I. priority rate limiting logic which limits control surface deflection rates as a function of the number of failed hydraulic. Typical results of this analysis are included, and listings of the subroutines are presented in appendicies.

  8. Structural integrity and failure mechanisms of a smart piezoelectric actuator under a cyclic bending mode

    NASA Astrophysics Data System (ADS)

    Woo, Sung-Choong; Goo, Nam Seo

    2008-08-01

    Information on the onset and evolution of damage within materials is essential for guaranteeing the integrity of actuator systems. The authors have evaluated the structural integrity and the failure mechanisms of smart composite actuators with a PZT ceramic plate under electric cyclic loading. For this, two kinds of actuators, actuator 1 and actuator 2, were manufactured. Prior to the main testing, performance testing was performed on the actuators to determine their resonant frequencies. Electric cyclic tests were conducted up to twenty million cycles. An acoustic emission technique was used for monitoring the damage evolution in real time. We observed the extent of the damage after testing using scanning electron microscopy and reflected optical microscopy to support characteristics in the acoustic emission behavior that corresponded to specific types of damage mechanisms. It was shown that the initial damage mechanism of the smart composite actuator under electric cyclic loading originated from the transgranular micro-fatigue damage in the PZT ceramic layer. With increasing cycles, a local intergranular crack initiated and developed onto the surface of the PZT ceramic layer or propagated into the internal layer. Finally, short-circuiting led to the electric breakdown of the actuator. These results were different depending on the drive frequencies and the configuration of the actuators. Moreover, we differentiated between the aforementioned damage mechanisms via AE signal pattern analyses based on the primary frequency and the waveform. From our results, we conclude that the drive frequency and the existence of a protecting layer are dominant factors in the structural integrity of the smart composite actuator.

  9. Fire protection countermeasures for containment ventilation systems

    SciTech Connect

    Alvares, N.; Beason, D.; Bergman, V.; Creighton, J.; Ford, H.; Lipska, A.

    1980-08-25

    The goal of this project is to find countermeasures to protect High Efficiency Particulate Air (HEPA) filters, in exit ventilation ducts, from the heat and smoke generated by fire. Initially, methods were developed to cool fire-heated air by fine water spray upstream of the filters. It was recognized that smoke aerosol exposure to HEPA filters could also cause disruption of the containment system. Through testing and analysis, several methods to partially mitigate the smoke exposure to the HEPA filters were identified. A continuous, movable, high-efficiency prefilter using modified commercial equipment was designed. The technique is capable of protecting HEPA filters over the total time duration of the test fires. The reason for success involved the modification of the prefiltration media. Commercially available filter media has particle sorption efficiency that is inversely proportional to media strength. To achieve properties of both efficiency and strength, rolling filter media were laminated with the desired properties. The approach was Edisonian, but truncation in short order to a combination of prefilters was effective. The application of this technique was qualified, since it is of use only to protect HEPA filters from fire-generated smoke aerosols. It is not believed that this technique is cost effective in the total spectrum of containment systems, especially if standard fire protection systems are available in the space. But in areas of high-fire risk, where the potential fuel load is large and ignition sources are plentiful, the complication of a rolling prefilter in exit ventilation ducts to protect HEPA filters from smoke aerosols is definitely justified.

  10. A micro-optical system for endoscopy based on mechanical compensation paradigm using miniature piezo-actuation.

    PubMed

    Cerveri, Pietro; Zazzarini, Cynthia Corinna; Patete, Paolo; Baroni, Guido

    2014-06-01

    The goal of the study was to investigate the feasibility of a novel miniaturized optical system for endoscopy. Fostering the mechanical compensation paradigm, the modeled optical system, composed by 14 lenses, separated in 4 different sets, had a total length of 15.55mm, an effective focal length ranging from 1.5 to 4.5mm with a zoom factor of about 2.8×, and an angular field of view up to 56°. Predicted maximum lens travel was less than 3.5mm. The consistency of the image plane height across the magnification range testified the zoom capability. The maximum predicted achromatic astigmatism, transverse spherical aberration, longitudinal spherical aberration and relative distortion were less than or equal to 25μm, 15μm, 35μm and 12%, respectively. Tests on tolerances showed that the manufacturing and opto-mechanics mounting are critical as little deviations from design dramatically decrease the optical performances. However, recent micro-fabrication technology can guarantee tolerances close to nominal design. A closed-loop actuation unit, devoted to move the zoom and the focus lens sets, was implemented adopting miniaturized squiggle piezo-motors and magnetic position encoders based on Hall effect. Performance results, using a prototypical test board, showed a positioning accuracy of less than 5μm along a lens travel path of 4.0mm, which was in agreement with the lens set motion features predicted by the analysis. In conclusion, this study demonstrated the feasibility of the optical design and the viability of the actuation approach while tolerances must be carefully taken into account.

  11. Dielectric Actuation of Polymers

    NASA Astrophysics Data System (ADS)

    Niu, Xiaofan

    Dielectric polymers are widely used in a plurality of applications, such as electrical insulation, dielectric capacitors, and electromechanical actuators. Dielectric polymers with large strain deformations under an electric field are named dielectric elastomers (DE), because of their relative low modulus, high elongation at break, and outstanding resilience. Dielectric elastomer actuators (DEA) are superior to traditional transducers as a muscle-like technology: large strains, high energy densities, high coupling efficiency, quiet operation, and light weight. One focus of this dissertation is on the design of DE materials with high performance and easy processing. UV radiation curing of reactive species is studied as a generic synthesis methodology to provide a platform for material scientists to customize their own DE materials. Oligomers/monomers, crosslinkers, and other additives are mixed and cured at appropriate ratios to control the stress-strain response, suppress electromechanical instability of the resulting polymers, and provide stable actuation strains larger than 100% and energy densities higher than 1 J/g. The processing is largely simplified in the new material system by removal of the prestretching step. Multilayer stack actuators with 11% linear strain are demonstrated in a procedure fully compatible with industrial production. A multifunctional DE derivative material, bistable electroactive polymer (BSEP), is invented enabling repeatable rigid-to-rigid deformation without bulky external structures. Bistable actuation allows the polymer actuator to have two distinct states that can support external load without device failure. Plasticizers are used to lower the glass transition temperature to 45 °C. Interpenetrating polymer network structure is established inside the BSEP to suppress electromechanical instability, providing a breakdown field of 194 MV/m and a stable bistable strain as large as 228% with a 97% strain fixity. The application of BSEP

  12. Dynamics simulation of pyro actuated "Ball Lock" separation system for micro-satellites to evaluate release shock

    NASA Astrophysics Data System (ADS)

    Somanath, S.; Krishnan Kutty, V. K.; Francis, E. J.

    2001-09-01

    Micro-satellite separation systems based on 'Ball Lock' release mechanism developed by ISRO for deploying microsatellites up to 150 kg mass has been successfully used in PSLV. Three varieties of such designs have been realised and qualified. They are designated as IBL230, IBL298 and IBL358. IBL stands for ISRO Ball Lock and the number stands for the interface diameter in mm. The system functions by releasing a preloaded ball locked joint between two rings by rotating a ball retainer ring using pyro assisted thrusters. This system is characterised by good joint stiffness, lightweight construction, tuneable jettisoning velocity, debris free actuation and redundancy in initiation. The system generates low release shock. To reduce the release shock further for sensitive spacecraft applications, the shock sources needs to be identified and suitable methods for attenuation to be chosen. The difficulty in identifying the contribution of shock from various sources was due to lack of complete understanding of system dynamics. Experimental verification was attempted to understand the dynamics of the release operations. Dynamic model of this system is generated for complete understanding of the release function and to quantify the impact forces that generate the shock. A dynamics model of the IBL298 system was generated. The pyro thrusters are the source of energy for release function. It is powered by ISRO standard cartridge with squib based electrical initiation. The firing of the cartridge generates pressure inside the thruster, which moves a piston and rotates the retainer ring. The pressure time relationship used for modelling is generated from the test data from a closed bomb test and used in the simulation by applying constituent equations. The system is modelled using second order dynamical equations. This model is made to capture the multiple contact losses that are likely to occur between the thruster and the lug of the ring during the movement. Magnitudes of the

  13. Incipient fault detection and power system protection for spaceborne systems

    NASA Technical Reports Server (NTRS)

    Russell, B. Don; Hackler, Irene M.

    1987-01-01

    A program was initiated to study the feasibility of using advanced terrestrial power system protection techniques for spacecraft power systems. It was designed to enhance and automate spacecraft power distribution systems in the areas of safety, reliability and maintenance. The proposed power management/distribution system is described as well as security assessment and control, incipient and low current fault detection, and the proposed spaceborne protection system. It is noted that the intelligent remote power controller permits the implementation of digital relaying algorithms with both adaptive and programmable characteristics.

  14. Pressure Systems Energy Release Protection (Gas Pressurized Systems)

    NASA Technical Reports Server (NTRS)

    Brown, S. J. (Editor)

    1986-01-01

    A survey of studies into hazards associated with closed or pressurized system rupture and preliminary guidelines for the performance design of primary, secondary, and protective receptors of these hazards are provided. The hazards discussed in the survey are: blast, fragments, ground motion, heat radiation, biological, and chemical. Performance guidelines for receptors are limited to pressurized systems that contain inert gas. The performance guidelines for protection against the remaining unaddressed degenerative hazards are to be covered in another study.

  15. Cathodic protection requirements for deepwater systems

    SciTech Connect

    Menendez, C.M.; Hanson, H.R.; Kane, R.D.; Farquhar, G.B.

    1999-07-01

    Field and laboratory experience related to requirements for cathodic protection (CP) in deep water are reviewed with emphasis on identification of the major variables that need to be specified for successful deepwater CP designs for offshore structures. The subject is addressed based on the historical development of cathodic protection design methodologies for offshore structures focusing on sacrificial anode systems and trends that have resulted in specific changes in design requirements. Three main subjects are discussed: (1) application of existing industry standards such as NACE RP0176; (2) environmental factors--dissolved oxygen, temperature, salinity, pH, water velocity and fouling; and (3) calcareous deposits--difference between shallow and deep waters. Current practice of design criteria and systems for deepwater applications is assessed, including initial polarization, use of coatings and anode materials. The results from laboratory tests are compared with available documented service experiences and field tests results.

  16. An algorithmic approach for fault-monitoring of electrical actuation system for all electric aircraft

    NASA Astrophysics Data System (ADS)

    Murthy, T. V. Rama; Krishnan, A.; Ajay, S.

    1991-10-01

    A current trend in fault detection and identification (FDI) is to use a combination of algorithmic procedural methods and artificial intelligence (AI) techniques. A method for monitoring faulty sensors in aircraft electrical actuators is presented. This method is based on static model based fault detection (MBFD) and parameter estimation based on on-line recursive least squares (RLS). Investigations were made of MBFD where measured variables were checked for consistency with those of the model. In the case study, owing to the wide variation of the poles of the overall transfer function, a reduced order model was chosen to model the process. Fault detection is also achieved by estimating the reduced order model parameters in the closed loop by RLS. It is found that RLS is reliable only on the addition of a PRBS dither signal to the input excitation. The combination of the two methods improves the fault detection probability while simultaneously reducing the false alarm probability. This yields a higher confidence level in the fault monitoring, especially in the context of the response of a reduced order model.

  17. Design and Performance Evaluation of Sensors and Actuators for Advanced Optical Systems

    NASA Technical Reports Server (NTRS)

    Clark, Natalie

    2011-01-01

    Current state-of-the-art commercial sensors and actuators do not meet many of NASA s next generation spacecraft and instrument needs. Nor do they satisfy the DoD needs for satellite missions, especially micro/nano satellite missions. In an effort to develop advanced optical devices and instruments that meet mission requirements, NASA Langley recently completed construction of a new cleanroom housing equipment capable of fabricating high performance active optic and adaptive optic technologies including deformable mirrors, reconfigurable lenses (both refractive and diffractive), spectrometers, spectro-polarimeters, tunable filters and many other active optic devices. In addition to performance, these advanced optic technologies offer advantages in speed, size, weight, power consumption, and radiation tolerance. The active optic devices described in this paper rely on birefringent liquid crystal materials to alter either the phase or the polarization of the incoming light. Design considerations and performance evaluation results for various NASA applications are presented. Applications presented will include large space telescopes, optical communications, spacecraft windows, coronagraphs, and star trackers. Keywords: Photonics, Adaptive Optics, Tunable Filters, MEMs., MOEMs, Coronagraph, Star Tracker

  18. Design and performance evaluation of sensors and actuators for advanced optical systems

    NASA Astrophysics Data System (ADS)

    Clark, Natalie

    2011-04-01

    Current state-of-the-art commercial sensors and actuators do not meet many of NASA's next generation spacecraft and instrument needs. Nor do they satisfy the DoD needs for satellite missions, especially micro/nano satellite missions. In an effort to develop advanced optical devices and instruments that meet mission requirements, NASA Langley recently completed construction of a new cleanroom housing equipment capable of fabricating high performance active optic and adaptive optic technologies including deformable mirrors, reconfigurable lenses (both refractive and diffractive), spectrometers, spectro-polarimeters, tunable filters and many other active optic devices. In addition to performance, these advanced optic technologies offer advantages in speed, size, weight, power consumption, and radiation tolerance. The active optic devices described in this paper rely on birefringent liquid crystal materials to alter either the phase or the polarization of the incoming light. Design considerations and performance evaluation results for various NASA applications are presented. Applications presented will include large space telescopes, optical communications, spacecraft windows, coronagraphs, and star trackers.

  19. Evaluation of control laws and actuator locations for control systems applicable to deformable astronomical telescope mirrors

    NASA Technical Reports Server (NTRS)

    Ostroff, A. J.

    1973-01-01

    Some of the major difficulties associated with large orbiting astronomical telescopes are the cost of manufacturing the primary mirror to precise tolerances and the maintaining of diffraction-limited tolerances while in orbit. One successfully demonstrated approach for minimizing these problem areas is the technique of actively deforming the primary mirror by applying discrete forces to the rear of the mirror. A modal control technique, as applied to active optics, has previously been developed and analyzed. The modal control technique represents the plant to be controlled in terms of its eigenvalues and eigenfunctions which are estimated via numerical approximation techniques. The report includes an extension of previous work using the modal control technique and also describes an optimal feedback controller. The equations for both control laws are developed in state-space differential form and include such considerations as stability, controllability, and observability. These equations are general and allow the incorporation of various mode-analyzer designs; two design approaches are presented. The report also includes a technique for placing actuator and sensor locations at points on the mirror based upon the flexibility matrix of the uncontrolled or unobserved modes of the structure. The locations selected by this technique are used in the computer runs which are described. The results are based upon three different initial error distributions, two mode-analyzer designs, and both the modal and optimal control laws.

  20. Lightning protection system for a wind turbine

    DOEpatents

    Costin, Daniel P.; Petter, Jeffrey K.

    2008-05-27

    In a wind turbine (104, 500, 704) having a plurality of blades (132, 404, 516, 744) and a blade rotor hub (120, 712), a lightning protection system (100, 504, 700) for conducting lightning strikes to any one of the blades and the region surrounding the blade hub along a path around the blade hub and critical components of the wind turbine, such as the generator (112, 716), gearbox (708) and main turbine bearings (176, 724).

  1. Auger Tension Leg Platform cathodic protection system

    SciTech Connect

    Goolsby, A.D.; Smith, J.D.

    1996-04-01

    Corrosion control design for the exterior submerged and buried steel surfaces of the 2,850 ft (869 m) water depth Auger Tension Leg Platform structure is described. Each major type of structural component has its own combination of coating and cathodic protection (CP) systems designed for a 35-year lifetime. Results of early in-service CP surveys of the tendons and guidebases are presented, showing the successful achievement of CP against seawater corrosion.

  2. Thermal Protection System of the Space Shuttle

    NASA Technical Reports Server (NTRS)

    Cleland, John; Iannetti, Francesco

    1989-01-01

    The Thermal Protection System (TPS), introduced by NASA, continues to incorporate many of the advances in materials over the past two decades. A comprehensive, single-volume summary of the TPS, including system design rationales, key design features, and broad descriptions of the subsystems of TPS (E.g., reusable surface insulation, leading edge structural, and penetration subsystems) is provided. Details of all elements of TPS development and application are covered (materials properties, manufacturing, modeling, testing, installation, and inspection). Disclosures and inventions are listed and potential commercial application of TPS-related technology is discussed.

  3. Commercial application of thermal protection system technology

    NASA Technical Reports Server (NTRS)

    Dyer, Gordon L.

    1991-01-01

    The thermal protection system process technology is examined which is used in the manufacture of the External Tank for the Space Shuttle system and how that technology is applied by private business to create new products, new markets, and new American jobs. The term 'technology transfer' means different things to different people and has become one of the buzz words of the 1980s and 1990s. Herein, technology transfer is defined as a means of transferring technology developed by NASA's prime contractors to public and private sector industries.

  4. River Protection Project information systems assessment

    SciTech Connect

    JOHNSON, A.L.

    1999-07-28

    The Information Systems Assessment Report documents the results from assessing the Project Hanford Management Contract (PHMC) Hanford Data Integrator 2000 (HANDI 2000) system, Business Management System (BMS) and Work Management System phases (WMS), with respect to the System Engineering Capability Assessment Model (CAM). The assessment was performed in accordance with the expectations stated in the fiscal year (FY) 1999 Performance Agreement 7.1.1, item (2) which reads, ''Provide an assessment report on the selected Integrated Information System by July 31, 1999.'' This report assesses the BMS and WMS as implemented and planned for the River Protection Project (RPP). The systems implementation is being performed under the PHMC HANDI 2000 information system project. The project began in FY 1998 with the BMS, proceeded in FY 1999 with the Master Equipment List portion of the WMS, and will continue the WMS implementation as funding provides. This report constitutes an interim quality assessment providing information necessary for planning RPP's information systems activities. To avoid confusion, HANDI 2000 will be used when referring to the entire system, encompassing both the BMS and WMS. A graphical depiction of the system is shown in Figure 2-1 of this report.

  5. Subsea valve actuator for ultra deepwater

    SciTech Connect

    Ali, S.Z.; Skeels, H.B.; Montemayor, B.K.; Williams, M.R.

    1996-12-31

    This paper reviews the continuing development of gate valve and actuator technology for subsea completions extending into ultra deep water. The basic technical challenges inherent to subsea valve actuators are reviewed, along with the various factors which affect the design and performance of these devices in deepwater applications. The high external ambient pressures which occur in deep water, coupled with high specific gravity hydraulic control fluids, are shown to have a significant impact on the performance of the actuators. This paper presents design and analysis methods and the verification test procedures which are required to develop and qualify new deep water actuator designs. Gate valve actuators of the type described in this paper are currently in use on subsea christmas trees on the world`s deepest subsea wells offshore Brazil (water depths >3,000 feet). New applications of the deepwater actuators are in process for upcoming Gulf of Mexico subsea production systems in water depths approaching 6,000 feet. The actuator/valve development method described in this paper has been confirmed by performance verification testing of full scale valves and actuators using a hyperbaric chamber to simulate ultra deepwater operating conditions. Performance of the test valves and actuators correlated very well with analytical predictions. Test results have confirmed that the new valve actuator designs will satisfy API 17D performance requirements for water depths up to 7,500 feet, well in excess of the upcoming GOM application.

  6. National Ignition Facility environmental protection systems

    SciTech Connect

    Mintz, J.M.; Reitz, T.C.; Tobin, M.T.

    1994-06-01

    The conceptual design of Environmental Protection Systems (EPS) for the National Ignition Facility (NIF) is described. These systems encompass tritium and activated debris handling, chamber, debris shield and general decontamination, neutron and gamma monitoring, and radioactive, hazardous and mixed waste handling. Key performance specifications met by EPS designs include limiting the tritium inventory to 300 Ci and total tritium release from NIF facilities to less than 10 Ci/yr. Total radiation doses attributable to NIF shall remain below 10 mrem/yr for any member of the general public and 500 mrem/yr for NIF staff. ALARA-based design features and operational procedures will, in most cases, result in much lower measured exposures. Waste minimization, improved cycle time and reduced exposures all result from the proposed CO2 robotic arm cleaning and decontamination system, while effective tritium control is achieved through a modern system design based on double containment and the proven detritiation technology.

  7. Characterization of a smartphone size haptic rendering system based on thin-film AlN actuators on glass substrates

    NASA Astrophysics Data System (ADS)

    Bernard, F.; Casset, F.; Danel, J. S.; Chappaz, C.; Basrour, S.

    2016-08-01

    This paper presents for the first time the characterization of a smartphone-size haptic rendering system based on the friction modulation effect. According to previous work and finite element modeling, the homogeneous flexural modes are needed to get the haptic feedback effect. The device studied consists of a thin film AlN transducers deposited on an 110  ×  65 mm2 glass substrate. The transducer’s localization on the glass plate allows a transparent central area of 90  ×  49 mm2. Electrical and mechanical parameters of the system are extracted from measurement. From this extraction, the electrical impedance matching reduced the applied voltage to 17.5 V AC and the power consumption to 1.53 W at the resonance frequency of the vibrating system to reach the haptic rendering specification. Transient characterizations of the actuation highlight a delay under the dynamic tactile detection. The characterization of the AlN transducers used as sensors, including the noise rejection, the delay or the output charge amplitude allows detections with high accuracy of any variation due to external influences. Those specifications are the first step to a low-power-consumption feedback-looped system.

  8. Advanced Extravehicular Protective System (AEPS) study

    NASA Technical Reports Server (NTRS)

    Williams, J. L.; Webbon, B. W.; Copeland, R. J.

    1972-01-01

    A summary is presented of Advanced Extravehicular Protective Systems (AEPS) for the future missions beyond Skylab in earth orbit, on the lunar surface, and on the Martian surface. The study concentrated on the origination of regenerable life support concepts for use in portable extravehicular protective systems, and included evaluation and comparison with expendable systems, and selection of life support subsystems. The study was conducted in two phases. In the first phase, subsystem concepts for performing life support functions in AEPS which are regenerable or partially regenerable were originated, and in addition, expendable subsystems were considered. Parametric data for each subsystem concept were evolved including subsystem weight and volume, power requirement, thermal control requirement; base regeneration equipment weight and volume, requirement. The second phase involved an evaluation of the impact of safety considerations involving redundant and/or backup systems on the selection of the regenerable life support subsystems. In addition, the impact of the space shuttle program on regenerable life support subsystem development was investigated.

  9. 29 CFR 1926.652 - Requirements for protective systems.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Excavations § 1926.652 Requirements for protective systems. (a) Protection of employees in excavations. (1) Each employee in an excavation shall be protected from cave-ins by an adequate protective system designed in accordance...

  10. Electromechanical actuator for thrust vector control

    NASA Astrophysics Data System (ADS)

    Zubkow, Zygmunt

    Attention is given to the development and testing of electromechanical actuator (EMA) systems for use in first- and second-stage thrust vector control of rocket engines. An overview of the test program is also presented. Designs for both first- and second-stage actuators employ redundant dc brushless, three-phase rare-earth permanent magnet motors. The first-stage actuator is about 28 hp per motor and uses a roller screw. Second-stage thrust vector control is implemented with a much smaller actuator of about 1 hp per motor. This actuator uses a gear drive with a recycling ball screw mechanism. An operational EMA is presented. This 6.5-in. actuator is capable of a stall force of 1350 pounds per motor and a frequency response of about 5 HZ.

  11. Control System Design Implementation and Preliminary Demonstration for a Tendon-Actuated Lightweight In-Space MANipulator (TALISMAN)

    NASA Technical Reports Server (NTRS)

    Komendera, Erik E.; Doggett, William R.; Dorsey, John T.; Debus, Thomas J.; Holub, Kris; Dougherty, Sean P.

    2015-01-01

    Satellite servicing is a high priority task for NASA and the space industry, addressing the needs of a variety of missions, and potentially lowering the overall cost of missions through refurbishment and reuse. However, the ability to service satellites is severely limited by the lack of long reach manipulation capability and inability to launch new devices due the end of the Space Transport System, or Space Shuttle Program. This paper describes the design and implementation of a control system for a Tendon-Actuated Lightweight In-Space MANipulator (TALISMAN), including; defining the forward and inverse kinematics, endpoint velocity to motor velocity, required cable tensions, and a proportional-integral-derivative (PID) controller. The tensions and velocities necessary to maneuver and capture small and large payloads are also discussed. To demonstrate the utility of the TALISMAN for satellite servicing, this paper also describes a satellite servicing demonstration using two TALISMAN prototypes to grasp and inspect a satellite mockup. Potential avenues for improving the control system are discussed.

  12. 14 CFR 23.1359 - Electrical system fire protection.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Electrical system fire protection. 23.1359... Electrical Systems and Equipment § 23.1359 Electrical system fire protection. (a) Each component of the electrical system must meet the applicable fire protection requirements of §§ 23.863 and 23.1182....

  13. 14 CFR 23.1359 - Electrical system fire protection.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Electrical system fire protection. 23.1359... Electrical Systems and Equipment § 23.1359 Electrical system fire protection. (a) Each component of the electrical system must meet the applicable fire protection requirements of §§ 23.863 and 23.1182....

  14. 14 CFR 23.1359 - Electrical system fire protection.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Electrical system fire protection. 23.1359... Electrical Systems and Equipment § 23.1359 Electrical system fire protection. (a) Each component of the electrical system must meet the applicable fire protection requirements of §§ 23.863 and 23.1182....

  15. 14 CFR 23.1359 - Electrical system fire protection.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Electrical system fire protection. 23.1359... Electrical Systems and Equipment § 23.1359 Electrical system fire protection. (a) Each component of the electrical system must meet the applicable fire protection requirements of §§ 23.863 and 23.1182....

  16. 14 CFR 23.1359 - Electrical system fire protection.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Electrical system fire protection. 23.1359... Electrical Systems and Equipment § 23.1359 Electrical system fire protection. (a) Each component of the electrical system must meet the applicable fire protection requirements of §§ 23.863 and 23.1182....

  17. TREAT Reactor Control and Protection System

    SciTech Connect

    Lipinski, W.C.; Brookshier, W.K.; Burrows, D.R.; Lenkszus, F.R.; McDowell, W.P.

    1985-01-01

    The main control algorithm of the Transient Reactor Test Facility (TREAT) Automatic Reactor Control System (ARCS) resides in Read Only Memory (ROM) and only experiment specific parameters are input via keyboard entry. Prior to executing an experiment, the software and hardware of the control computer is tested by a closed loop real-time simulation. Two computers with parallel processing are used for the reactor simulation and another computer is used for simulation of the control rod system. A monitor computer, used as a redundant diverse reactor protection channel, uses more conservative setpoints and reduces challenges to the Reactor Trip System (RTS). The RTS consists of triplicated hardwired channels with one out of three logic. The RTS is automatically tested by a digital Dedicated Microprocessor Tester (DMT) prior to the execution of an experiment. 6 refs., 5 figs., 1 tab.

  18. Fault-tolerant reactor protection system

    DOEpatents

    Gaubatz, Donald C.

    1997-01-01

    A reactor protection system having four divisions, with quad redundant sensors for each scram parameter providing input to four independent microprocessor-based electronic chassis. Each electronic chassis acquires the scram parameter data from its own sensor, digitizes the information, and then transmits the sensor reading to the other three electronic chassis via optical fibers. To increase system availability and reduce false scrams, the reactor protection system employs two levels of voting on a need for reactor scram. The electronic chassis perform software divisional data processing, vote 2/3 with spare based upon information from all four sensors, and send the divisional scram signals to the hardware logic panel, which performs a 2/4 division vote on whether or not to initiate a reactor scram. Each chassis makes a divisional scram decision based on data from all sensors. Each division performs independently of the others (asynchronous operation). All communications between the divisions are asynchronous. Each chassis substitutes its own spare sensor reading in the 2/3 vote if a sensor reading from one of the other chassis is faulty or missing. Therefore the presence of at least two valid sensor readings in excess of a set point is required before terminating the output to the hardware logic of a scram inhibition signal even when one of the four sensors is faulty or when one of the divisions is out of service.

  19. Fault-tolerant reactor protection system

    DOEpatents

    Gaubatz, D.C.

    1997-04-15

    A reactor protection system is disclosed having four divisions, with quad redundant sensors for each scram parameter providing input to four independent microprocessor-based electronic chassis. Each electronic chassis acquires the scram parameter data from its own sensor, digitizes the information, and then transmits the sensor reading to the other three electronic chassis via optical fibers. To increase system availability and reduce false scrams, the reactor protection system employs two levels of voting on a need for reactor scram. The electronic chassis perform software divisional data processing, vote 2/3 with spare based upon information from all four sensors, and send the divisional scram signals to the hardware logic panel, which performs a 2/4 division vote on whether or not to initiate a reactor scram. Each chassis makes a divisional scram decision based on data from all sensors. Each division performs independently of the others (asynchronous operation). All communications between the divisions are asynchronous. Each chassis substitutes its own spare sensor reading in the 2/3 vote if a sensor reading from one of the other chassis is faulty or missing. Therefore the presence of at least two valid sensor readings in excess of a set point is required before terminating the output to the hardware logic of a scram inhibition signal even when one of the four sensors is faulty or when one of the divisions is out of service. 16 figs.

  20. Thermal Protection Systems: Past, Present and Future

    NASA Technical Reports Server (NTRS)

    Johnson, Sylvia M.

    2015-01-01

    Thermal protection materials and systems (TPS) have been critical to fulfilling humankinds desire to explore space. Composite and ceramic materials have enabled the early missions to orbit, the moon, the space station, Mars with robots, and sample return. Crewed missions to Mars are being considered, and this places even more demands on TPS materials. This talk will give some history on the materials used for earth and planetary entry and the demands placed upon such materials. TPS needs for future missions, especially to Mars, will be identified and potential solutions discussed.

  1. Self-contained clothing system provides protection against hazardous environments

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Self-contained clothing system protects personnel against hazardous environments. The clothing has an environmental control system and a complete protection envelope consisting of an outer garment, inner garment, underwear, boots, gloves, and helmet.

  2. Micromachined electrostatic vertical actuator

    DOEpatents

    Lee, Abraham P.; Sommargren, Gary E.; McConaghy, Charles F.; Krulevitch, Peter A.

    1999-10-19

    A micromachined vertical actuator utilizing a levitational force, such as in electrostatic comb drives, provides vertical actuation that is relatively linear in actuation for control, and can be readily combined with parallel plate capacitive position sensing for position control. The micromachined electrostatic vertical actuator provides accurate movement in the sub-micron to micron ranges which is desirable in the phase modulation instrument, such as optical phase shifting. For example, compact, inexpensive, and position controllable micromirrors utilizing an electrostatic vertical actuator can replace the large, expensive, and difficult-to-maintain piezoelectric actuators. A thirty pound piezoelectric actuator with corner cube reflectors, as utilized in a phase shifting diffraction interferometer can be replaced with a micromirror and a lens. For any very precise and small amplitudes of motion` micromachined electrostatic actuation may be used because it is the most compact in size, with low power consumption and has more straightforward sensing and control options.

  3. Smart composite material system with sensor, actuator, and processor functions: a model of holding and releasing a ball

    NASA Astrophysics Data System (ADS)

    Oishi, Ryutaro; Yoshida, Hitoshi; Nagai, Hideki; Xu, Ya; Jang, Byung-Koog

    2002-07-01

    A smart composite material system which has three smart functions of sensor, actuator and processor has been developed intend to apply to structure of house for controlling ambient temperature and humidity, hands of robot for holding and feeling an object, and so on. A carbon fiber reinforced plastics (CFRP) is used as matrix in the smart composite. The size of the matrix is 120mm x 24mm x 0.45mm. The CFRP plate is combined two Ni-Ti shape memory alloy (SMA) wires with an elastic rubber to construct a composite material. The composite material has a characteristic of reversible response with respect to temperature. A photo-sensor and temperature sensor are embedded in the composite material. The composite material has a processor function to combine with a simple CPU (processor) unit. For demonstrating the capability of the composite material system, a model is built up for controlling certain behaviors such as gripping and releasing a spherical object. The amplitude of gripping force is (3.0 plus/minus 0.3) N in the measurement, which is consistent with our calculation of 2.7 N. Out of a variety of functions to be executed by the CPU, it is shown to exert calculation and decision making in regard to object selection, object holding, and ON-OFF control of action by external commands.

  4. An intelligent sensor array distributed system for vibration analysis and acoustic noise characterization of a linear switched reluctance actuator.

    PubMed

    Salvado, José; Espírito-Santo, António; Calado, Maria

    2012-01-01

    This paper proposes a distributed system for analysis and monitoring (DSAM) of vibrations and acoustic noise, which consists of an array of intelligent modules, sensor modules, communication bus and a host PC acting as data center. The main advantages of the DSAM are its modularity, scalability, and flexibility for use of different type of sensors/transducers, with analog or digital outputs, and for signals of different nature. Its final cost is also significantly lower than other available commercial solutions. The system is reconfigurable, can operate either with synchronous or asynchronous modes, with programmable sampling frequencies, 8-bit or 12-bit resolution and a memory buffer of 15 kbyte. It allows real-time data-acquisition for signals of different nature, in applications that require a large number of sensors, thus it is suited for monitoring of vibrations in Linear Switched Reluctance Actuators (LSRAs). The acquired data allows the full characterization of the LSRA in terms of its response to vibrations of structural origins, and the vibrations and acoustic noise emitted under normal operation. The DSAM can also be used for electrical machine condition monitoring, machine fault diagnosis, structural characterization and monitoring, among other applications.

  5. An Intelligent Sensor Array Distributed System for Vibration Analysis and Acoustic Noise Characterization of a Linear Switched Reluctance Actuator

    PubMed Central

    Salvado, José; Espírito-Santo, António; Calado, Maria

    2012-01-01

    This paper proposes a distributed system for analysis and monitoring (DSAM) of vibrations and acoustic noise, which consists of an array of intelligent modules, sensor modules, communication bus and a host PC acting as data center. The main advantages of the DSAM are its modularity, scalability, and flexibility for use of different type of sensors/transducers, with analog or digital outputs, and for signals of different nature. Its final cost is also significantly lower than other available commercial solutions. The system is reconfigurable, can operate either with synchronous or asynchronous modes, with programmable sampling frequencies, 8-bit or 12-bit resolution and a memory buffer of 15 kbyte. It allows real-time data-acquisition for signals of different nature, in applications that require a large number of sensors, thus it is suited for monitoring of vibrations in Linear Switched Reluctance Actuators (LSRAs). The acquired data allows the full characterization of the LSRA in terms of its response to vibrations of structural origins, and the vibrations and acoustic noise emitted under normal operation. The DSAM can also be used for electrical machine condition monitoring, machine fault diagnosis, structural characterization and monitoring, among other applications. PMID:22969364

  6. Aggregation of magnetic microparticles in the context of targeted therapies actuated by a magnetic resonance imaging system

    NASA Astrophysics Data System (ADS)

    Mathieu, Jean-Baptiste; Martel, Sylvain

    2009-08-01

    A study of magnetic aggregation in the context of magnetic resonance imaging (MRI) based actuated targeting is proposed. MRI systems can induce displacement forces on magnetized particles as they flow through the blood vessels. Magnetic aggregation of the particles happens when they are placed within the magnetic field of the MRI system and can greatly influence the MRI steering dynamics of magnetic particles. In this paper, a review of the different parameters that can be used to tailor the size, geometry, stiffness, and density of magnetic aggregates is proposed. Then, magnetic aggregation experiments on a suspension of Fe3O4 microparticles ranging from 0.1 to 100 μm in diameter are described. The effects of particle concentration, flow rate, and magnetic field amplitude were evaluated. Field amplitudes of 1.5 mT, 0.4 T, and 1.5 T fields were applied without any magnetic steering gradients and caused aggregates that could sometimes exceed 1 mm in length. Since magnetic aggregates can reach higher magnetophoretic velocities than individual particles, large aggregates could be exploited in larger arteries with important blood flows. A few strategies are discussed to assist in the design of MRI steering experiments by enhancing the positive effects of magnetic aggregation over its negative effects.

  7. Reliable Mixed H∞ and Passivity-Based Control for Fuzzy Markovian Switching Systems With Probabilistic Time Delays and Actuator Failures.

    PubMed

    Sakthivel, Rathinasamy; Selvi, Subramaniam; Mathiyalagan, Kalidass; Shi, Peng

    2015-12-01

    This paper is concerned with the problem of reliable mixed H ∞ and passivity-based control for a class of stochastic Takagi-Sugeno (TS) fuzzy systems with Markovian switching and probabilistic time varying delays. Different from the existing works, the H∞ and passivity control problem with probabilistic occurrence of time-varying delays and actuator failures is considered in a unified framework, which is more general in some practical situations. The main aim of this paper is to design a reliable mixed H∞ and passivity-based controller such that the stochastic TS fuzzy system with Markovian switching is stochastically stable with a prescribed mixed H∞ and passivity performance level γ > 0 . Based on the Lyapunov-Krasovskii functional (LKF) involving lower and upper bound of probabilistic time delay and convex combination technique, a new set of delay-dependent sufficient condition in terms of linear matrix inequalities (LMIs) is established for obtaining the required result. Finally, a numerical example based on the modified truck-trailer model is given to demonstrate the effectiveness and applicability of the proposed design techniques.

  8. Privacy protection schemes for fingerprint recognition systems

    NASA Astrophysics Data System (ADS)

    Marasco, Emanuela; Cukic, Bojan

    2015-05-01

    The deployment of fingerprint recognition systems has always raised concerns related to personal privacy. A fingerprint is permanently associated with an individual and, generally, it cannot be reset if compromised in one application. Given that fingerprints are not a secret, potential misuses besides personal recognition represent privacy threats and may lead to public distrust. Privacy mechanisms control access to personal information and limit the likelihood of intrusions. In this paper, image- and feature-level schemes for privacy protection in fingerprint recognition systems are reviewed. Storing only key features of a biometric signature can reduce the likelihood of biometric data being used for unintended purposes. In biometric cryptosystems and biometric-based key release, the biometric component verifies the identity of the user, while the cryptographic key protects the communication channel. Transformation-based approaches only a transformed version of the original biometric signature is stored. Different applications can use different transforms. Matching is performed in the transformed domain which enable the preservation of low error rates. Since such templates do not reveal information about individuals, they are referred to as cancelable templates. A compromised template can be re-issued using a different transform. At image-level, de-identification schemes can remove identifiers disclosed for objectives unrelated to the original purpose, while permitting other authorized uses of personal information. Fingerprint images can be de-identified by, for example, mixing fingerprints or removing gender signature. In both cases, degradation of matching performance is minimized.

  9. Lightweight Thermal Protection System for Atmospheric Entry

    NASA Technical Reports Server (NTRS)

    Stewart, David; Leiser, Daniel

    2007-01-01

    TUFROC (Toughened Uni-piece Fibrous Reinforced Oxidation-resistant Composite) has been developed as a new thermal protection system (TPS) material for wing leading edge and nose cap applications. The composite withstands temperatures up to 1,970 K, and consists of a toughened, high-temperature surface cap and a low-thermal-conductivity base, and is applicable to both sharp and blunt leading edge vehicles. This extends the possible application of fibrous insulation to the wing leading edge and/or nose cap on a hypersonic vehicle. The lightweight system comprises a treated carbonaceous cap composed of ROCCI (Refractory Oxidation-resistant Ceramic Carbon Insulation), which provides dimensional stability to the outer mold line, while the fibrous base material provides maximum thermal insulation for the vehicle structure.

  10. 3D Multifunctional Ablative Thermal Protection System

    NASA Technical Reports Server (NTRS)

    Feldman, Jay; Venkatapathy, Ethiraj; Wilkinson, Curt; Mercer, Ken

    2015-01-01

    NASA is developing the Orion spacecraft to carry astronauts farther into the solar system than ever before, with human exploration of Mars as its ultimate goal. One of the technologies required to enable this advanced, Apollo-shaped capsule is a 3-dimensional quartz fiber composite for the vehicle's compression pad. During its mission, the compression pad serves first as a structural component and later as an ablative heat shield, partially consumed on Earth re-entry. This presentation will summarize the development of a new 3D quartz cyanate ester composite material, 3-Dimensional Multifunctional Ablative Thermal Protection System (3D-MAT), designed to meet the mission requirements for the Orion compression pad. Manufacturing development, aerothermal (arc-jet) testing, structural performance, and the overall status of material development for the 2018 EM-1 flight test will be discussed.

  11. Carbon adsorption system protects LPG storage sphere

    SciTech Connect

    Gothenquist, C.A.; Rooker, K.M.

    1996-07-01

    Chevron U.S.A. Products Co. installed a carbon adsorption system to protect an LPG storage sphere at its refinery in Richmond, Calif. Vessel damage can result when amine contamination leads to emulsion formation and consequent amine carry-over, thus promoting wet-H{sub 2}S cracking. In Chevron`s No. 5 H{sub 2}S recovery plant, a mixture of butane and propane containing H{sub 2}S is contacted with diethanolamine (DEA) in a liquid-liquid absorber. The absorber is a countercurrent contactor with three packed beds. Because the sweetening system did not include a carbon adsorption unit for amine purification, contaminants were building up in the DEA. The contaminants comprised: treatment chemicals, hydrocarbons, foam inhibitors, and amine degradation products. The paper describes the solution to this problem.

  12. Electromagnetic rotational actuation.

    SciTech Connect

    Hogan, Alexander Lee

    2010-08-01

    There are many applications that need a meso-scale rotational actuator. These applications have been left by the wayside because of the lack of actuation at this scale. Sandia National Laboratories has many unique fabrication technologies that could be used to create an electromagnetic actuator at this scale. There are also many designs to be explored. In this internship exploration of the designs and fabrications technologies to find an inexpensive design that can be used for prototyping the electromagnetic rotational actuator.

  13. Advanced power system protection and incipient fault detection and protection of spaceborne power systems

    NASA Technical Reports Server (NTRS)

    Russell, B. Don

    1989-01-01

    This research concentrated on the application of advanced signal processing, expert system, and digital technologies for the detection and control of low grade, incipient faults on spaceborne power systems. The researchers have considerable experience in the application of advanced digital technologies and the protection of terrestrial power systems. This experience was used in the current contracts to develop new approaches for protecting the electrical distribution system in spaceborne applications. The project was divided into three distinct areas: (1) investigate the applicability of fault detection algorithms developed for terrestrial power systems to the detection of faults in spaceborne systems; (2) investigate the digital hardware and architectures required to monitor and control spaceborne power systems with full capability to implement new detection and diagnostic algorithms; and (3) develop a real-time expert operating system for implementing diagnostic and protection algorithms. Significant progress has been made in each of the above areas. Several terrestrial fault detection algorithms were modified to better adapt to spaceborne power system environments. Several digital architectures were developed and evaluated in light of the fault detection algorithms.

  14. Electrostatically actuatable light modulating device

    DOEpatents

    Koehler, Dale R.

    1991-01-01

    The electrostatically actuatable light modulator utilizes an opaque substrate plate patterned with an array of aperture cells, the cells comprised of physically positionable dielectric shutters and electrostatic actuators. With incorporation of a light source and a viewing screen, a projection display system is effected. Inclusion of a color filter array aligned with the aperture cells accomplishes a color display. The system is realized in terms of a silicon based manufacturing technology allowing fabrication of a high resolution capability in a physically small device which with the utilization of included magnification optics allows both large and small projection displays.

  15. Pneumatically actuated micropipetting device

    NASA Astrophysics Data System (ADS)

    Szita, Nicolas; Buser, Rudolf A.

    1998-03-01

    We have realized a valveless micropipetting device with an integrated sensor which can aspirate and dispense liquid volumes without any valves, hence without any reflow or dead volume. With an external pneumatic actuation, we have demonstrated aspirating and dispensing from 190nl of 6 (mu) l of water. Measurements showed a standard deviation of down to 1 percent. An integrated capacitive sensor will allow monitoring of the pressure throughout the pipetting process and detect malfunctions, e.g. clotting of the pipetting tip. It is our intention to use this demonstrated precise aspiration mechanism in combination with a micromachined reaction chamber and a miniaturized optical analysis system.

  16. Remote monitoring of a Fire Protection System

    NASA Astrophysics Data System (ADS)

    Bauman, Steven; Vermeulen, Tom; Roberts, Larry; Matsushige, Grant; Gajadhar, Sarah; Taroma, Ralph; Elizares, Casey; Arruda, Tyson; Potter, Sharon; Hoffman, James

    2011-03-01

    Some years ago CFHT proposed developing a Remote Observing Environment aimed at producing Science Observations at their Observatory Facility on Mauna Kea from their Headquarters facility in Waimea, HI. This Remote Observing Project commonly referred to as OAP (Observatory Automation Project) was completed at the end of January 2011 and has been providing the majority of Science Data since. My poster will discuss the upgrades to the existing fire alarm protection system. With no one at the summit during nightly operations, the observatory facility required automated monitoring of the facility for safety to personnel and equipment in the case of a fire. An addressable analog fire panel was installed which utilizes digital communication protocol (DCP), intelligent communication with other devices, and an RS-232 interface which provides feedback and real-time monitoring of the system. Using the interface capabilities of the panel, it provides notifications when heat detectors, smoke sensors, manual pull stations, or the main observatory computer room fire suppression system has been activated. The notifications are sent out as alerts to staff in the form of test massages and emails and the observing control GUI interface alerts the remote telescope operator with a map showing the location of the fire occurrence and type of device that has been triggered. And all of this was accomplished without the need for an outside vendor to monitor the system and facilitate warnings or notifications regarding the system.

  17. Implantable centrifugal blood pump with dual impeller and double pivot bearing system: electromechanical actuator, prototyping, and anatomical studies.

    PubMed

    Bock, Eduardo; Antunes, Pedro; Leao, Tarcisio; Uebelhart, Beatriz; Fonseca, Jeison; Leme, Juliana; Utiyama, Bruno; da Silva, Cibele; Cavalheiro, Andre; Filho, Diolino Santos; Dinkhuysen, Jarbas; Biscegli, Jose; Andrade, Aron; Arruda, Celso

    2011-05-01

    An implantable centrifugal blood pump has been developed with original features for a left ventricular assist device. This pump is part of a multicenter and international study with the objective to offer simple, affordable, and reliable devices to developing countries. Previous computational fluid dynamics investigations and wear evaluation in bearing system were performed followed by prototyping and in vitro tests. In addition, previous blood tests for assessment of normalized index of hemolysis show results of 0.0054±2.46 × 10⁻³ mg/100 L. An electromechanical actuator was tested in order to define the best motor topology and controller configuration. Three different topologies of brushless direct current motor (BLDCM) were analyzed. An electronic driver was tested in different situations, and the BLDCM had its mechanical properties tested in a dynamometer. Prior to evaluation of performance during in vivo animal studies, anatomical studies were necessary to achieve the best configuration and cannulation for left ventricular assistance. The results were considered satisfactory, and the next step is to test the performance of the device in vivo.

  18. Space shuttle rudder/speedbrake actuation subsystem

    NASA Technical Reports Server (NTRS)

    Naber, R. A.

    1985-01-01

    The Rudder/Speedbrake (R/SB) Actuation Subsystem for use on the NASA Space Shuttle Orbiter is an electro-hydro-mechanical system which provides the control and positionary capability of the orbiter aero-dynamic primary flight control surface. The system is located in the vehicle's vertical stabilizer. The geared rotary actuators provide a power hinge feature of the split panel rudder. Actuation of both panels in the same direction provides conventional rudder control; actuating the panels differentially provides a speedbrake function intended to control both speed and pitch. The commands may be superimposed on one another. The system consists of one power drive unit which responds to quadredundant avionic signals to generate a rotary output, four geared rotary actuators, which develop rotary position and torque as outputs, and ten torque transmitting drive-shifts.

  19. Two Community Protective Service Systems: Comparative Evaluation of Systems Operations.

    ERIC Educational Resources Information Center

    Johnson, Clara L.

    Presented are the findings of a study conducted to evaluate two community protective service systems in terms of the mechanisms for identifying and handling child abuse and neglect cases and the effectiveness of intervention. It is noted that data was collected in two sites: Site I (Nashville, Tennessee), which has an emergency reporting system…

  20. Omnidirectional Actuator Handle

    NASA Technical Reports Server (NTRS)

    Moetteli, John B.

    1995-01-01

    Proposed actuator handle comprises two normally concentric rings, cables, and pulleys arranged such that relative displacement of rings from concentricity results in pulling of cable and consequent actuation of associated mechanism. Unlike conventional actuator handles like levers on farm implements, actuated from one or two directions only, proposed handle reached from almost any direction and actuated by pulling or pushing inner ring in any direction with respect to outer ring. Flanges installed on inner ring to cover gap between inner ring and housing to prevent clothing from being caught.

  1. Bimorphic polymeric photomechanical actuator

    NASA Technical Reports Server (NTRS)

    Sarkisov, Sergey S. (Inventor); Curley, Michael J. (Inventor); Adamovsky, Grigory (Inventor); Sarkisov, Jr., Sergey S. (Inventor); Fields, Aisha B. (Inventor)

    2006-01-01

    A bimorphic polymeric photomechanical actuator, in one embodiment using polyvinylidene fluoride (PVDF) as a photosensitive body, transmitting light over fiber optic cables, and controlling the shape and pulse duration of the light pulse to control movement of the actuator. Multiple light beams are utilized to generate different ranges of motion for the actuator from a single photomechanical body and alternative designs use multiple light beams and multiple photomechanical bodies to provide controlled movement. Actuator movement using one or more ranges of motion is utilized to control motion to position an actuating element in three dimensional space.

  2. Electro-optic architecture for servicing sensors and actuators in advanced aircraft propulsion systems

    NASA Technical Reports Server (NTRS)

    Poppel, G. L.; Glasheen, W. M.

    1989-01-01

    A detailed design of a fiber optic propulsion control system, integrating favored sensors and electro-optics architecture is presented. Layouts, schematics, and sensor lists describe an advanced fighter engine system model. Components and attributes of candidate fiber optic sensors are identified, and evaluation criteria are used in a trade study resulting in favored sensors for each measurand. System architectural ground rules were applied to accomplish an electro-optics architecture for the favored sensors. A key result was a considerable reduction in signal conductors. Drawings, schematics, specifications, and printed circuit board layouts describe the detailed system design, including application of a planar optical waveguide interface.

  3. Design of Transpiration Cooled Thermal Protection Systems

    NASA Technical Reports Server (NTRS)

    Callens, E. Eugene, Jr.; Vinet, Robert F.

    1999-01-01

    This study explored three approaches for the utilization of transpiration cooling in thermal protection systems. One model uses an impermeable wall with boiling water heat transfer at the backface (Model I). A second model uses a permeable wall with a boiling water backface and additional heat transfer to the water vapor as it flows in channels toward the exposed surface (Model II). The third model also uses a permeable wall, but maintains a boiling condition at the exposed surface of the material (Model III). The governing equations for the models were developed in non-dimensional form and a comprehensive parametric investigation of the effects of the independent variables on the important dependent variables was performed. In addition, detailed analyses were performed for selected materials to evaluate the practical limitations of the results of the parametric study.

  4. Reusable Metallic Thermal Protection Systems Development

    NASA Technical Reports Server (NTRS)

    Blosser, Max L.; Martin, Carl J.; Daryabeigi, Kamran; Poteet, Carl C.

    1998-01-01

    Metallic thermal protection systems (TPS) are being developed to help meet the ambitious goals of future reusable launch vehicles. Recent metallic TPS development efforts at NASA Langley Research Center are described. Foil-gage metallic honeycomb coupons, representative of the outer surface of metallic TPS were subjected to low speed impact, hypervelocity impact, rain erosion, and subsequent arcjet exposure. TPS panels were subjected to thermal vacuum, acoustic, and hot gas flow testing. Results of the coupon and panel tests are presented. Experimental and analytical tools are being developed to characterize and improve internal insulations. Masses of metallic TPS and advanced ceramic tile and blanket TPS concepts are compared for a wide range of parameters.

  5. Overview of the Orion Thermal Protection System

    NASA Technical Reports Server (NTRS)

    Kowal, T. John

    2010-01-01

    The Orion spacecraft is being developed as part of the Constellation Exploration Program and will serve as the United States crewed transportation system to the International Space Station after the retirement of the Space Shuttle in 2010 and as the eventual means to return U.S. astronauts to the Moon. Therefore, Orion is being designed for reentry missions from both low Earth orbit and from Lunar-return trajectories. This presentation will provide an overview of the development of the Orion TPS, a critical component in the development of the spacecraft. The thermal protection system (TPS) that protects the crew module from the extreme environments associated with Earth atmospheric reentry consists of a forward heatshield and an aft backshell. The requirements that drive the design of the TPS will be discussed, including several key requirements that establish a precedent for U.S. human-rated spacecraft. For the first time in U.S. human spaceflight, a vehicle s TPS is being designed with a specific, derived requirement for reliability. Also, due to the increased presence of spacecraft in Earth s orbit in recent decades, requirements for micro-meteoroid/orbital debris damage tolerance are also a driving requirement that has affected the selection of portions of the TPS. The efforts to select materials and to define a preliminary design for both the heatshield and the backshell will be described. This will include a discussion of the design challenges presented by the numerous penetrations on both the backshell and the heatshield. Finally, the verification and validation plan which is currently under development to certify the TPS for human-rated missions will be outlined. To support the execution of this plan, a ground test campaign for both thermal and structural performance is being designed. This test campaign will directly support thermal and thermal/structural analyses that also are fundamental to the certification effort.

  6. Development of shape memory alloy (SMA)-based actuator for remotely piloted vehicles (RPVs)

    NASA Astrophysics Data System (ADS)

    Prasad, M. Hari

    2003-10-01

    While the experimental use of shape memory alloys (SMAs) is widespread in aerospace integrated actuation systems, much of the practical value of SMA technology is realized in linear and rotary actuators. This report will introduce an attempt to develop a full-scaled SMA based actuator to replace electro-mechanical actuator for flap actuation of a Remotely Piloted Vehicle (RPV). At the heart of this actuator there is thermally sensitive wire that, when heated, contracts and provides useable mechanical energy. This linear actuation is converted into rotary, for the required actuation of flap. The actuator configurations were sized to fit inside the wing of the RPV where presently the electro-mechanical actuator is housed. The torque supplied to the flap is similarly calculated from full-scale requirements. Using common engineering principles, this design will demonstrate how to design a typical SMA actuator. Test of the actuator performance (stroke, force movement) is done on special test fixture.

  7. Crash-Fire Protection System for T-56 Turbopropeller Engine Using Water as Cooling and Inerting Agent

    NASA Technical Reports Server (NTRS)

    Busch, Arthur M.; Campbell, John A.

    1959-01-01

    A crash-fire protection system to suppress the ignition of crash-spilled fuel that may be ingested by a T-56 turbopropeller engine is described. This system includes means for rapidly extinguishing the combustor flame and means for cooling and inerting with water the hot engine parts likely to ignite engine-ingested fuel. Combustion-chamber flames were extinguished in 0.07 second at the engine fuel manifold. Hot engine parts were inerted and cooled by 52 pounds of water discharged at ten engine stations. Performance trials of the crash-fire prevention system were conducted by bringing the engine up to takeoff temperature, stopping the normal fuel flow to the engine, starting the water discharge, and then spraying fuel into the engine to simulate crash-ingested fuel. No fires occurred during these trials, although fuel was sprayed into the engine from 0.3 second to 15 minutes after actuating the crash-fire protection system.

  8. An autonomous actuator driven by fluctuations in ambient humidity

    NASA Astrophysics Data System (ADS)

    Arazoe, Hiroki; Miyajima, Daigo; Akaike, Kouki; Araoka, Fumito; Sato, Emiko; Hikima, Takaaki; Kawamoto, Masuki; Aida, Takuzo

    2016-10-01

    Devices that respond to negligibly small fluctuations in environmental conditions will be of great value for the realization of more sustainable, low-power-consumption actuators and electronic systems. Herein we report an unprecedented film actuator that seemingly operates autonomously, because it responds to the adsorption and desorption of a minute amount of water (several hundred nanograms per 10 mm2) possibly induced by fluctuations in the ambient humidity. The actuation is extremely rapid (50 ms for one curl) and can be repeated >10,000 times without deterioration. On heating or light irradiation, the film loses adsorbed water and bends quickly, so that it can jump vertically up to 10 mm from a surface or hit a glass bead. The film consists of a π-stacked carbon nitride polymer, formed by one-pot vapour-deposition polymerization of guanidinium carbonate, and is characterized by a tough, ultralightweight and highly anisotropic layered structure. An actuator partially protected against water adsorption is also shown to walk unidirectionally.

  9. Force protection demining system (FPDS) detection subsystem

    NASA Astrophysics Data System (ADS)

    Zachery, Karen N.; Schultz, Gregory M.; Collins, Leslie M.

    2005-06-01

    This study describes the U.S. Army Force Protection Demining System (FPDS); a remotely-operated, multisensor platform developed for reliable detection and neutralization of both anti-tank and anti-personnel landmines. The ongoing development of the prototype multisensor detection subsystem is presented, which integrates an advanced electromagnetic pulsed-induction array and ground penetrating synthetic aperture radar array on a single standoff platform. The FPDS detection subsystem is mounted on a robotic rubber-tracked vehicle and incorporates an accurate and precise navigation/positioning module making it well suited for operation in varied and irregular terrains. Detection sensors are optimally configured to minimize interference without loss in sensitivity or performance. Mine lane test data acquired from the prototype sensors are processed to extract signal- and image-based features for automatic target recognition. Preliminary results using optimal feature and classifier selection indicate the potential of the system to achieve high probabilities of detection while minimizing false alarms. The FPDS detection software system also exploits modern multi-sensor data fusion algorithms to provide real-time detection and discrimination information to the user.

  10. 14 CFR 23.954 - Fuel system lightning protection.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Fuel system lightning protection. 23.954... Fuel System § 23.954 Fuel system lightning protection. The fuel system must be designed and arranged to prevent the ignition of fuel vapor within the system by— (a) Direct lightning strikes to areas having...

  11. 14 CFR 23.954 - Fuel system lightning protection.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fuel system lightning protection. 23.954... Fuel System § 23.954 Fuel system lightning protection. The fuel system must be designed and arranged to prevent the ignition of fuel vapor within the system by— (a) Direct lightning strikes to areas having...

  12. 14 CFR 23.954 - Fuel system lightning protection.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Fuel system lightning protection. 23.954... Fuel System § 23.954 Fuel system lightning protection. The fuel system must be designed and arranged to prevent the ignition of fuel vapor within the system by— (a) Direct lightning strikes to areas having...

  13. 14 CFR 23.954 - Fuel system lightning protection.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Fuel system lightning protection. 23.954... Fuel System § 23.954 Fuel system lightning protection. The fuel system must be designed and arranged to prevent the ignition of fuel vapor within the system by— (a) Direct lightning strikes to areas having...

  14. 14 CFR 23.954 - Fuel system lightning protection.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Fuel system lightning protection. 23.954... Fuel System § 23.954 Fuel system lightning protection. The fuel system must be designed and arranged to prevent the ignition of fuel vapor within the system by— (a) Direct lightning strikes to areas having...

  15. Out-of-Plane Translational PZT Bimorph Actuator with Archimedes’ Spiral Actuating Tethers

    NASA Astrophysics Data System (ADS)

    Yang, Chenye; Liu, Sanwei; Livermore, Carol

    2015-12-01

    The design, finite element analysis (FEA), and experimental characterization of a MEMS out-of-plane (vertical) translational lead-zirconate-titanate (PZT) bimorph actuator supported on Archimedes’ spiral tethers are presented. Two types of bimorph actuators with different electrode patterns (with spiral tethers half actuated or fully actuated) are designed and fabricated. Both designs are fabricated by commercial processes and are compatible with integration into more complex MEMS systems. Finite element analysis (FEA) was used to analyze and predict the displacements of both types of actuators. The deflections of both fully- actuated and half-actuated devices were measured experimentally to validate the design. At an applied voltage of 110V, the out-of-plane deflections of the actuators with half-actuated and fully-actuated tethers were measured at about 17 μm and 29 μm respectively, in good agreement with FEA predictions of 17.1 μm and 25.8 μm. The corresponding blocking forces are predicted as 10 mN and 17 mN by FEA.

  16. Reliability enhancement of APR + diverse protection system regarding common cause failures

    SciTech Connect

    Oh, Y. G.; Kim, Y. M.; Yim, H. S.; Lee, S. J.

    2012-07-01

    The Advanced Power Reactor Plus (APR +) nuclear power plant design has been developed on the basis of the APR1400 (Advanced Power Reactor 1400 MWe) to further enhance safety and economics. For the mitigation of Anticipated Transients Without Scram (ATWS) as well as Common Cause Failures (CCF) within the Plant Protection System (PPS) and the Emergency Safety Feature - Component Control System (ESF-CCS), several design improvement features have been implemented for the Diverse Protection System (DPS) of the APR + plant. As compared to the APR1400 DPS design, the APR + DPS has been designed to provide the Safety Injection Actuation Signal (SIAS) considering a large break LOCA accident concurrent with the CCF. Additionally several design improvement features, such as channel structure with redundant processing modules, and changes of system communication methods and auto-system test methods, are introduced to enhance the functional reliability of the DPS. Therefore, it is expected that the APR + DPS can provide an enhanced safety and reliability regarding possible CCF in the safety-grade I and C systems as well as the DPS itself. (authors)

  17. 49 CFR 179.18 - Thermal protection systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... jackets, insulation, and thermal protection. A complete record of each analysis shall be made, retained... 49 Transportation 3 2012-10-01 2012-10-01 false Thermal protection systems. 179.18 Section 179.18... § 179.18 Thermal protection systems. (a) Performance standard. When the regulations in this...

  18. 49 CFR 179.18 - Thermal protection systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... jackets, insulation, and thermal protection. A complete record of each analysis shall be made, retained... 49 Transportation 3 2014-10-01 2014-10-01 false Thermal protection systems. 179.18 Section 179.18... § 179.18 Thermal protection systems. (a) Performance standard. When the regulations in this...

  19. 49 CFR 179.18 - Thermal protection systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... jackets, insulation, and thermal protection. A complete record of each analysis shall be made, retained... 49 Transportation 3 2013-10-01 2013-10-01 false Thermal protection systems. 179.18 Section 179.18... § 179.18 Thermal protection systems. (a) Performance standard. When the regulations in this...

  20. 49 CFR 179.18 - Thermal protection systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... jackets, insulation, and thermal protection. A complete record of each analysis shall be made, retained... 49 Transportation 3 2011-10-01 2011-10-01 false Thermal protection systems. 179.18 Section 179.18... § 179.18 Thermal protection systems. (a) Performance standard. When the regulations in this...

  1. A wirelessly programmable actuation and sensing system for structural health monitoring

    NASA Astrophysics Data System (ADS)

    Long, James; Büyüköztürk, Oral

    2016-04-01

    Wireless sensor networks promise to deliver low cost, low power and massively distributed systems for structural health monitoring. A key component of these systems, particularly when sampling rates are high, is the capability to process data within the network. Although progress has been made towards this vision, it remains a difficult task to develop and program 'smart' wireless sensing applications. In this paper we present a system which allows data acquisition and computational tasks to be specified in Python, a high level programming language, and executed within the sensor network. Key features of this system include the ability to execute custom application code without firmware updates, to run multiple users' requests concurrently and to conserve power through adjustable sleep settings. Specific examples of sensor node tasks are given to demonstrate the features of this system in the context of structural health monitoring. The system comprises of individual firmware for nodes in the wireless sensor network, and a gateway server and web application through which users can remotely submit their requests.

  2. Systems, methods, and products for graphically illustrating and controlling a droplet actuator

    NASA Technical Reports Server (NTRS)

    Paik, Philip Y. (Inventor); Pollack, Michael G. (Inventor); Sturmer, Ryan A. (Inventor); Smith, Gregory F. (Inventor); Brafford, Keith R. (Inventor); Pamula, Vamsee K. (Inventor)

    2010-01-01

    Systems for controlling a droplet microactuator are provided. According to one embodiment, a system is provided and includes a controller, a droplet microactuator electronically coupled to the controller, and a display device displaying a user interface electronically coupled to the controller, wherein the system is programmed and configured to permit a user to effect a droplet manipulation by interacting with the user interface. According to another embodiment, a system is provided and includes a processor, a display device electronically coupled to the processor, and software loaded and/or stored in a storage device electronically coupled to the controller, a memory device electronically coupled to the controller, and/or the controller and programmed to display an interactive map of a droplet microactuator. According to yet another embodiment, a system is provided and includes a controller, a droplet microactuator electronically coupled to the controller, a display device displaying a user interface electronically coupled to the controller, and software for executing a protocol loaded and/or stored in a storage device electronically coupled to the controller, a memory device electronically coupled to the controller, and/or the controller.

  3. Progress on Shape Memory Alloy Actuator Development for Active Clearance Control

    NASA Technical Reports Server (NTRS)

    DeCastro, Jonathan; Melcher, Kevin; Noebe, Ronald

    2006-01-01

    Results of a numerical analysis evaluating the feasibility of high-temperature shape memory alloys (HTSMA) for active clearance control actuation in the high-pressure turbine section of a modern turbofan engine has been conducted. The prototype actuator concept considered here consists of parallel HTSMA wires attached to the shroud that is located on the exterior of the turbine case. A transient model of an HTSMA actuator was used to evaluate active clearance control at various operating points in a test bed aircraft engine simulation. For the engine under consideration, each actuator must be designed to counteract loads from 380 to 2000 lbf and displace at least 0.033 in. Design results show that an actuator comprised of 10 wires 2 in. in length is adequate for control at critical engine operating points and still exhibit acceptable failsafe operability and cycle life. A proportional-integral-derivative (PID) controller with integrator windup protection was implemented to control clearance amidst engine transients during a normal mission. Simulation results show that the control system exhibits minimal variability in clearance control performance across the operating envelope. The final actuator design is sufficiently small to fit within the limited space outside the high-pressure turbine case and is shown to consume only small amounts of bleed air to adequately regulate temperature.

  4. Performance study of a hydrogen powered metal hydride actuator

    NASA Astrophysics Data System (ADS)

    Mainul Hossain Bhuiya, Md; Kim, Kwang J.

    2016-04-01

    A thermally driven hydrogen powered actuator integrating metal hydride hydrogen storage reactor, which is compact, noiseless, and able to generate smooth actuation, is presented in this article. To test the plausibility of a thermally driven actuator, a conventional piston type actuator was integrated with LaNi5 based hydrogen storage system. Copper encapsulation followed by compaction of particles into pellets, were adopted to improve overall thermal conductivity of the reactor. The operation of the actuator was thoroughly investigated for an array of operating temperature ranges. Temperature swing of the hydride reactor triggering smooth and noiseless actuation over several operating temperature ranges were monitored for quantification of actuator efficiency. Overall, the actuator generated smooth and consistent strokes during repeated cycles of operation. The efficiency of the actuator was found to be as high as 13.36% for operating a temperature range of 20 °C-50 °C. Stress-strain characteristics, actuation hysteresis etc were studied experimentally. Comparison of stress-strain characteristics of the proposed actuator with traditional actuators, artificial muscles and so on was made. The study suggests that design modification and use of high pressure hydride may enhance the performance and broaden the application horizon of the proposed actuator in future.

  5. Flexible dielectric elastomer actuators for wearable human-machine interfaces

    NASA Astrophysics Data System (ADS)

    Bolzmacher, Christian; Biggs, James; Srinivasan, Mandayam

    2006-03-01

    Wearable dielectric elastomer actuators have the potential to enable new technologies, such as tactile feedback gloves for virtual reality, and to improve existing devices, such as automatic blood pressure cuffs. They are potentially lighter, quieter, thinner, simpler, and cheaper than pneumatic and hydraulic systems now used to make compliant, actuated interfaces with the human body. Achieving good performance without using a rigid frame to prestrain the actuator is a fundamental challenge in using these actuators on body. To answer this challenge, a new type of fiber-prestrained composite actuator was developed. Equations that facilitate design of the actuator are presented, along with FE analysis, material tests, and experimental results from prototypes. Bending stiffness of the actuator material was found to be comparable to textiles used in clothing, confirming wearability. Two roll-to-roll machines are also presented that permit manufacture of this material in bulk as a modular, compact, prestressed composite that can be cut, stacked, and staggered, in order to build up actuators for a range of desired forces and displacements. The electromechanical properties of single- layered actuators manufactured by this method were measured (N=5). At non-damaging voltages, blocking force ranged from 3,7-5,0 gram per centimeter of actuator width, with linear strains of 20,0-30%. Driving the actuators to breakdown produced maximum force of 8,3-10 gram/cm, and actuation strain in excess 30%. Using this actuator, a prototype tactile display was constructed and demonstrated.

  6. Robust adaptive tracking control of MIMO nonlinear systems in the presence of actuator hysteresis

    NASA Astrophysics Data System (ADS)

    Fu, Guiyuan; Ou, Linlin; Zhang, Weidong

    2016-07-01

    Adaptive tracking control of a class of MIMO nonlinear system preceded by unknown hysteresis is investigated. Based on dynamic surface control, an adaptive robust control law is developed and compensators are designed to mitigate the influences of both the unknown bounded external uncertainties and the unknown Prandtl-Islinskii hysteresis. By adopting the low-pass filters, the explosion of complexity caused by tedious computation of the time derivatives of the virtual control laws is overcome. With the proposed control scheme, the closed-loop system is proved to be semi-globally ultimately bounded by the Lyapunov stability theory, and the output of the controlled system can track the desired trajectories with an arbitrarily small error. Finally, numerical simulations are given to verify the effectiveness of the proposed approach.

  7. Nonlinear gain-scheduling output-feedback control for polynomial nonlinear systems subject to actuator saturation

    NASA Astrophysics Data System (ADS)

    Wu, Fen; Hays, Scott

    2013-09-01

    This paper investigates nonlinear gain-scheduling control approaches for a class of polynomial nonlinear systems, containing an output-dependent vector field with input saturation. Using the polytopic differential inclusion and norm-bounded differential inclusion (NDI) of saturation and dead-zone functions, the nonlinear plants are transformed into systems with measurable parameters. For the polytopic differential inclusion description, a quasi-linear parameter varying (quasi-LPV) output-feedback controller will be sought for saturation control. On the other hand, the NDI model leads to a nonlinear fractional transformation (NFT) output-feedback controller for saturated nonlinear systems. The quasi-LPV and NFT output-feedback control synthesis conditions are derived in the forms of output-dependent matrix inequalities. They can be reformulated as sum-of-squares (SOS) optimisations and solved efficiently using SOS programming. The proposed nonlinear gain-scheduling saturation control approaches will be demonstrated using the Van der Pol equation.

  8. Asymmetrical booster guidance and control system design study. Volume 3: Space shuttle vehicle SRB actuator failure study. [space shuttle development

    NASA Technical Reports Server (NTRS)

    Williams, F. E.; Lemon, R. S.

    1974-01-01

    The investigation of single actuator failures on the space shuttle solid rocket booster required the analysis of both square pattern and diamond pattern actuator configurations. It was determined that for failures occuring near or prior to the region of maximum dynamic pressure, control gain adjustments can be used to achieve virtually nominal mid-boost vehicle behavior. A distinct worst case failure condition was established near staging that could significantly delay staging. It is recommended that the square pattern be retained as a viable alternative to the baseline diamond pattern because the staging transient is better controlled resulting in earlier staging.

  9. High Temperature Aerogels for Thermal Protection Systems

    NASA Technical Reports Server (NTRS)

    Hurwitz, Frances I.; Mbah, Godfrey C.

    2008-01-01

    High temperature aerogels in the Al2O3-SiO2 system are being investigated as possible constituents for lightweight integrated thermal protection system (TPS) designs for use in supersonic and hypersonic applications. Gels are synthesized from ethoxysilanes and AlCl3.6H2O, using an epoxide catalyst. The influence of Al:Si ratio, solvent, water to metal and water to alcohol ratios on aerogel composition, morphology, surface area, and pore size distribution were examined, and phase transformation on heat treatment characterized. Aerogels have been fabricated which maintain porous, fractal structures after brief exposures to 1000 C. Incorporation of nanofibers, infiltration of aerogels into SiC foams, use of polymers for crosslinking the aerogels, or combinations of these, offer potential for toughening and integration of TPS with composite structure. Woven fabric composites having Al2O3-SiO2 aerogels as a matrix also have been fabricated. Continuing work is focused on reduction in shrinkage and optimization of thermal and physical properties.

  10. Advanced Metallic Thermal Protection System Development

    NASA Technical Reports Server (NTRS)

    Blosser, M. L.; Chen, R. R.; Schmidt, I. H.; Dorsey, J. T.; Poteet, C. C.; Bird, R. K.

    2002-01-01

    A new Adaptable, Robust, Metallic, Operable, Reusable (ARMOR) thermal protection system (TPS) concept has been designed, analyzed, and fabricated. In addition to the inherent tailorable robustness of metallic TPS, ARMOR TPS offers improved features based on lessons learned from previous metallic TPS development efforts. A specific location on a single-stage-to-orbit reusable launch vehicle was selected to develop loads and requirements needed to design prototype ARMOR TPS panels. The design loads include ascent and entry heating rate histories, pressures, acoustics, and accelerations. Additional TPS design issues were identified and discussed. An iterative sizing procedure was used to size the ARMOR TPS panels for thermal and structural loads as part of an integrated TPS/cryogenic tank structural wall. The TPS panels were sized to maintain acceptable temperatures on the underlying structure and to operate under the design structural loading. Detailed creep analyses were also performed on critical components of the ARMOR TPS panels. A lightweight, thermally compliant TPS support system (TPSS) was designed to connect the TPS to the cryogenic tank structure. Four 18-inch-square ARMOR TPS panels were fabricated. Details of the fabrication process are presented. Details of the TPSS for connecting the ARMOR TPS panels to the externally stiffened cryogenic tank structure are also described. Test plans for the fabricated hardware are presented.

  11. Engine protection system for recoverable rocket booster

    NASA Technical Reports Server (NTRS)

    Shelby, Jr., Jerry A. (Inventor)

    1994-01-01

    A rocket engine protection system for a recoverable rocket booster which is arranged to land in a salt water body in substantially a nose down attitude. The system includes an inflatable bag which is stowed on a portion of a flat annular rim of the aft skirt of the booster. The bag is hinged at opposing sides and is provided with springs that urge the bag open. The bag is latched in a stowed position during launch and prior to landing for recovery is unlatched to permit the bag to be urged open and into sealing engagement with the rim. A source of pressurized gas further inflates the bag and urges it into sealing engagement with the rim of the skirt where it is locked into position. The gas provides a positive pressure upon the interior of the bag to preclude entry of salt water into the skirt and into contact with the engine. A flotation arrangement may assist in precluding the skirt of the booster from becoming submerged.

  12. Thermal Management and Thermal Protection Systems

    NASA Technical Reports Server (NTRS)

    Hasnain, Aqib

    2016-01-01

    's rays directly impinging on the system. Heating rate of the lamps were calculated by knowing fraction of emitted energy in a wavelength interval and the filament temperature. This version of the model can be used to predict performance of the system under vacuum with extreme cold or hot conditions. Initial testing of the PTMS showed promise, and the thermal math model predicts even better performance in thermal vacuum testing. ii) Thermal Protection Systems (TPS) are required for vehicles which enter earth's atmosphere to protect from aerodynamic heating caused by the friction between the vehicle and atmospheric gases. Orion's heat shield design has two aspects which needed to be analyzed thermally: i) a small excess of adhesive used to bond the outer AVCOAT layer to the inner composite structure tends to seep from under the AVCOAT and form a small bead in between two bricks of AVCOAT, ii) a silicone rubber with different thermophysical properties than AVCOAT fills the gap between two bricks of AVCOAT. I created a thermal model using TD to determine temperature differences that are caused by these two features. To prevent false results, all TD models must be verified against something known. In this case, the TD model was correlated to CHAR, an ablation modelling software used to analyze TPS. Analyzing a node far from the concerning features, we saw that the TD model data match CHAR data, verifying the TD model. Next, the temperature of the silicone rubber as well as the bead of adhesive were analyzed to determine if they exceeded allowable temperatures. It was determined that these two features do not have a significant effect on the max temperature of the heat shield. This model can be modified to check temperatures at various locations of the heat shield where the composite thickness varies.

  13. Redundancy of hydraulic flight control actuators

    NASA Technical Reports Server (NTRS)

    Chenoweth, C. C.; Ryder, D. R.

    1976-01-01

    The constraint of requiring airplanes to have inherent aerodynamic stability can be removed by using active control systems. The resulting airplane requires control system reliability approaching that of the basic airframe. Redundant control actuators can be used to achieve the required reliability, but create mechanization and operational problems. Of numerous candidate systems, two different approaches to solving the problems associated with redundant actuators which appear the most likely to be used in advanced airplane control systems are described.

  14. Sensor-less force-reflecting macro-micro telemanipulation systems by piezoelectric actuators.

    PubMed

    Amini, H; Farzaneh, B; Azimifar, F; Sarhan, A A D

    2016-09-01

    This paper establishes a novel control strategy for a nonlinear bilateral macro-micro teleoperation system with time delay. Besides position and velocity signals, force signals are additionally utilized in the control scheme. This modification significantly improves the poor transparency during contact with the environment. To eliminate external force measurement, a force estimation algorithm is proposed for the master and slave robots. The closed loop stability of the nonlinear micro-micro teleoperation system with the proposed control scheme is investigated employing the Lyapunov theory. Consequently, the experimental results verify the efficiency of the new control scheme in free motion and during collision between the slave robot and the environment of slave robot with environment, and the efficiency of the force estimation algorithm. PMID:27329852

  15. Sensor-less force-reflecting macro-micro telemanipulation systems by piezoelectric actuators.

    PubMed

    Amini, H; Farzaneh, B; Azimifar, F; Sarhan, A A D

    2016-09-01

    This paper establishes a novel control strategy for a nonlinear bilateral macro-micro teleoperation system with time delay. Besides position and velocity signals, force signals are additionally utilized in the control scheme. This modification significantly improves the poor transparency during contact with the environment. To eliminate external force measurement, a force estimation algorithm is proposed for the master and slave robots. The closed loop stability of the nonlinear micro-micro teleoperation system with the proposed control scheme is investigated employing the Lyapunov theory. Consequently, the experimental results verify the efficiency of the new control scheme in free motion and during collision between the slave robot and the environment of slave robot with environment, and the efficiency of the force estimation algorithm.

  16. Rack Protection Monitor - A Simple System

    SciTech Connect

    Orr, S.

    1997-12-01

    The Rack Protection Monitor is a simple, fail-safe device to monitor smoke, temperature and ventilation sensors. It accepts inputs from redundant sensors and has a hardwired algorithm to prevent nuisance power trips due to random sensor failures. When a sensor is triggered the Rack Protection Monitor latches and annunicates the alarm. If another sensor is triggered, the Rack Protection Monitor locally shuts down the power to the relay rack and sends alarm to central control.

  17. Actuated Hybrid Mirror Telescope

    NASA Technical Reports Server (NTRS)

    Hickey, Gregory; Redding, David; Lowman, Andrew; Cohen, David; Ohara, Catherine

    2005-01-01

    The figure depicts the planned Actuated Hybrid Mirror Telescope (AHMT), which is intended to demonstrate a new approach to the design and construction of wide-aperture spaceborne telescopes for astronomy and Earth science. This technology is also appropriate for Earth-based telescopes. The new approach can be broadly summarized as using advanced lightweight mirrors that can be manufactured rapidly at relatively low cost. More specifically, it is planned to use precise replicated metallic nanolaminate mirrors to obtain the required high-quality optical finishes. Lightweight, dimensionally stable silicon carbide (SiC) structures will support the nanolaminate mirrors in the required surface figures. To enable diffraction- limited telescope performance, errors in surface figures will be corrected by use of mirror-shape-control actuators that will be energized, as needed, by a wave-front-sensing and control system. The concepts of nanolaminate materials and mirrors made from nanolaminate materials were discussed in several previous NASA Tech Briefs articles. Nanolaminates constitute a relatively new class of materials that can approach theoretical limits of stiffness and strength. Nanolaminate mirrors are synthesized by magnetron sputter deposition of metallic alloys and/or compounds on optically precise master surfaces to obtain optical-quality reflector surfaces backed by thin shell structures. As an integral part of the deposition process, a layer of gold that will constitute the reflective surface layer is deposited first, eliminating the need for a subsequent and separate reflective-coating process. The crystallographic textures of the nanolaminate will be controlled to optimize the performance of the mirror. The entire deposition process for making a nanolaminate mirror takes less than 100 hours, regardless of the mirror diameter. Each nanolaminate mirror will be bonded to its lightweight SiC supporting structure. The lightweight nanolaminate mirrors and Si

  18. Nuclear plant-aging research on reactor protection systems

    SciTech Connect

    Meyer, L.C.

    1988-01-01

    This report presents the rsults of a review of the Reactor Trip System (RTS) and the Engineered Safety Feature Actuating System (ESFAS) operating experiences reported in Licensee Event Reports (LER)s, the Nuclear Power Experience data base, Nuclear Plant Reliability Data System, and plant maintenance records. Our purpose is to evaluate the potential significance of aging, including cycling, trips, and testing as contributors to degradation of the RTS and ESFAS. Tables are presented that show the percentage of events for RTS and ESFAS classified by cause, components, and subcomponents for each of the Nuclear Steam Supply System vendors. A representative Babcock and Wilcox plant was selected for detailed study. The US Nuclear Regulatory Commission's Nuclear Plant Aging Research guidelines were followed in performing the detailed study that identified materials susceptible to aging, stressors, environmental factors, and failure modes for the RTS and ESFAS as generic instrumentation and control systems. Functional indicators of degradation are listed, testing requirements evaluated, and regulatory issues discussed.

  19. Evaluation of several corrosion protective coating systems on aluminum

    NASA Technical Reports Server (NTRS)

    Higgins, R. H.

    1981-01-01

    A study of several protective coating systems for use on aluminum in seawater/seacoast environments was conducted to review the developments made on protective coatings since early in the Space Shuttle program and to perform comparative studies on these coatings to determine their effectiveness for providing corrosion protection during exposure to seawater/seacoast environments. Panels of 2219-T87 aluminum were coated with 21 different systems and exposed to a 5 percent salt spray for 4000 hr. Application properties, adhesion measurements, heat resistance and corrosion protection were evaluated. For comparative studies, the presently specified Bostik epoxy system used on the SRB structures was included. Results of these tests indicate four systems with outstanding performance and four additional systems with protection almost as good. These systems are based on a chromated pretreatment, a chromate epoxy primer, and a polyurethane topcoat. Consideration for one of these systems should be included for those applications where superior corrosion protection for aluminum surfaces is required.

  20. Design of feedback control systems for stable plants with saturating actuators

    NASA Technical Reports Server (NTRS)

    Kapasouris, Petros; Athans, Michael; Stein, Gunter

    1988-01-01

    A systematic control design methodology is introduced for multi-input/multi-output stable open loop plants with multiple saturations. This new methodology is a substantial improvement over previous heuristic single-input/single-output approaches. The idea is to introduce a supervisor loop so that when the references and/or disturbances are sufficiently small, the control system operates linearly as designed. For signals large enough to cause saturations, the control law is modified in such a way as to ensure stability and to preserve, to the extent possible, the behavior of the linear control design. Key benefits of the methodology are: the modified compensator never produces saturating control signals, integrators and/or slow dynamics in the compensator never windup, the directional properties of the controls are maintained, and the closed loop system has certain guaranteed stability properties. The advantages of the new design methodology are illustrated in the simulation of an academic example and the simulation of the multivariable longitudinal control of a modified model of the F-8 aircraft.

  1. Motorized actuation system to perform droplet operations on printed plastic sheets.

    PubMed

    Kong, Taejoon; Brien, Riley; Njus, Zach; Kalwa, Upender; Pandey, Santosh

    2016-05-21

    We developed an open microfluidic system to dispense and manipulate discrete droplets on planar plastic sheets. Here, a superhydrophobic material is spray-coated on commercially-available plastic sheets followed by the printing of hydrophilic symbols using an inkjet printer. The patterned plastic sheets are taped to a two-axis tilting platform, powered by stepper motors, that provides mechanical agitation for droplet transport. We demonstrate the following droplet operations: transport of droplets of different sizes, parallel transport of multiple droplets, merging and mixing of multiple droplets, dispensing of smaller droplets from a large droplet or a fluid reservoir, and one-directional transport of droplets. As a proof-of-concept, a colorimetric assay is implemented to measure the glucose concentration in sheep serum. Compared to silicon-based digital microfluidic devices, we believe that the presented system is appealing for various biological experiments because of the ease of altering design layouts of hydrophilic symbols, relatively faster turnaround time in printing plastic sheets, larger area to accommodate more tests, and lower operational costs by using off-the-shelf products. PMID:27080172

  2. Integrated piezoelectric actuators in deep drawing tools

    NASA Astrophysics Data System (ADS)

    Neugebauer, R.; Mainda, P.; Drossel, W.-G.; Kerschner, M.; Wolf, K.

    2011-04-01

    The production of car body panels are defective in succession of process fluctuations. Thus the produced car body panel can be precise or damaged. To reduce the error rate, an intelligent deep drawing tool was developed at the Fraunhofer Institute for Machine Tools and Forming Technology IWU in cooperation with Audi and Volkswagen. Mechatronic components in a closed-loop control is the main differentiating factor between an intelligent and a conventional deep drawing tool. In correlation with sensors for process monitoring, the intelligent tool consists of piezoelectric actuators to actuate the deep drawing process. By enabling the usage of sensors and actuators at the die, the forming tool transform to a smart structure. The interface between sensors and actuators will be realized with a closed-loop control. The content of this research will present the experimental results with the piezoelectric actuator. For the analysis a production-oriented forming tool with all automotive requirements were used. The disposed actuators are monolithic multilayer actuators of the piezo injector system. In order to achieve required force, the actuators are combined in a cluster. The cluster is redundant and economical. In addition to the detailed assembly structures, this research will highlight intensive analysis with the intelligent deep drawing tool.

  3. An airjet actuator system for identification of the human arm joint mechanical properties.

    PubMed

    Xu YMj; Hunter, I W; Hollerbach, J M; Bennett, D J

    1991-11-01

    A system is described for determining the mechanical properties of the human arm during unconstrained posture and movement. An airjet perturbation device is attached to the wrist with a special cuff, and provides high-frequency stochastic perturbations in potentially three orthogonal directions. The airjet operates as a fluidic flip-flop utilizing the Coanda effect, and generates binary force sequences with a steady-state thrust of 4 N, a flat frequency response to 75 Hz, usable thrust to 150 Hz, and a rise time of 1 ms, when the static pressure at the nozzle inlet is 5.5 x 10(5) Pa (80 psi). These operating characteristics are adequate to identify the arm's mechanical properties efficiently and robustly. PMID:1748446

  4. Detonator cable initiation system safety investigation: Consequences of energizing the detonator and actuator cables

    SciTech Connect

    Osher, J.; Chau, H.; Von Holle, W.

    1994-03-01

    This study was performed to explore and assess the worst-case response of a W89-type weapons system, damaged so as to expose detonator and/or detonator safing strong link (DSSL) cables to the most extreme, credible lightning-discharge, environment. The test program used extremely high-current-level, fast-rise-time (1- to 2-{mu}s) discharges to simulate lightning strikes to either the exposed detonator or DSSL cables. Discharges with peak currents above 700 kA were required to explode test sections of detonator cable and launch a flyer fast enough potentially to detonate weapon high explosive (HE). Detonator-safing-strong-link (DSSL) cables were exploded in direct contact with hot LX-17 and Ultrafine TATB (UFTATB). At maximum charging voltage, the discharge system associated with the HE firing chamber exploded the cables at more than 600-kA peak current; however, neither LX-17 nor UFTATB detonated at 250{degree}C. Tests showed that intense surface arc discharges of more than 700 kA/cm in width across the surface of hot UFTATB [generally the more sensitive of the two insensitive high explosives (IHE)] could not initiate this hot IHE. As an extension to this study, we applied the same technique to test sections of the much-narrower but thicker-cover-layer W87 detonator cable. These tests were performed at the same initial stored electrical energy as that used for the W89 study. Because of the narrower cable conductor in the W87 cables, discharges greater than 550-kA peak current were sufficient to explode the cable and launch a fast flyer. In summary, we found that lightning strikes to exposed DSSL cables cannot directly detonate LX-17 or UFTATB even at high temperatures, and they pose no HE safety threat.

  5. MEMS fluidic actuator

    DOEpatents

    Kholwadwala, Deepesh K.; Johnston, Gabriel A.; Rohrer, Brandon R.; Galambos, Paul C.; Okandan, Murat

    2007-07-24

    The present invention comprises a novel, lightweight, massively parallel device comprising microelectromechanical (MEMS) fluidic actuators, to reconfigure the profile, of a surface. Each microfluidic actuator comprises an independent bladder that can act as both a sensor and an actuator. A MEMS sensor, and a MEMS valve within each microfluidic actuator, operate cooperatively to monitor the fluid within each bladder, and regulate the flow of the fluid entering and exiting each bladder. When adjacently spaced in a array, microfluidic actuators can create arbitrary surface profiles in response to a change in the operating environment of the surface. In an embodiment of the invention, the profile of an airfoil is controlled by independent extension and contraction of a plurality of actuators, that operate to displace a compliant cover.

  6. Thermostatic Valves Containing Silicone-Oil Actuators

    NASA Technical Reports Server (NTRS)

    Bhandari, Pradeep; Birur, Gajanana C.; Bame, David P.; Karlmann, Paul B.; Prina, Mauro; Young, William; Fisher, Richard

    2009-01-01

    Flow-splitting and flow-mixing thermally actuated spool valves have been developed for controlling flows of a heat-transfer fluid in a temperature-regulation system aboard the Mars Science Laboratory (MSL) rover. Valves like these could also be useful in terrestrial temperature-regulation systems, including automobile air-conditioning systems and general refrigeration systems. These valves are required to provide smoother actuation over a wider temperature range than the flow-splitting, thermally actuated spool valves used in the Mars Explorer Rover (MER). Also, whereas the MER valves are unstable (tending to oscillate) in certain transition temperature ranges, these valves are required not to oscillate. The MER valves are actuated by thermal expansion of a wax against spring-loaded piston rods (as in common automotive thermostats). The MSL valves contain similar actuators that utilize thermal expansion of a silicone oil, because silicone-oil actuators were found to afford greater and more nearly linear displacements, needed for smoother actuation, over the required wider temperature range. The MSL valves also feature improved spool designs that reflect greater understanding of fluid dynamics, consideration of pressure drops in valves, and a requirement for balancing of pressures in different flow branches.

  7. Electro-optic architecture (EOA) for sensors and actuators in aircraft propulsion systems

    NASA Technical Reports Server (NTRS)

    Glomb, W. L., Jr.

    1989-01-01

    Results of a study to design an optimal architecture for electro-optical sensing and control in advanced aircraft and space systems are described. The propulsion full authority digital Electronic Engine Control (EEC) was the focus for the study. The recommended architecture is an on-engine EEC which contains electro-optic interface circuits for fiber-optic sensors on the engine. Size and weight are reduced by multiplexing arrays of functionally similar sensors on a pair of optical fibers to common electro-optical interfaces. The architecture contains common, multiplex interfaces to seven sensor groups: (1) self luminous sensors; (2) high temperatures; (3) low temperatures; (4) speeds and flows; (5) vibration; (6) pressures; and (7) mechanical positions. Nine distinct fiber-optic sensor types were found to provide these sensing functions: (1) continuous wave (CW) intensity modulators; (2) time division multiplexing (TDM) digital optic codeplates; (3) time division multiplexing (TDM) analog self-referenced sensors; (4) wavelength division multiplexing (WDM) digital optic code plates; (5) wavelength division multiplexing (WDM) analog self-referenced intensity modulators; (6) analog optical spectral shifters; (7) self-luminous bodies; (8) coherent optical interferometers; and (9) remote electrical sensors. The report includes the results of a trade study including engine sensor requirements, environment, the basic sensor types, and relevant evaluation criteria. These figures of merit for the candidate interface types were calculated from the data supplied by leading manufacturers of fiber-optic sensors.

  8. Planetary Protection Considerations in EVA System Design

    NASA Technical Reports Server (NTRS)

    Eppler, Dean B.; Kosmo, Joseph J.

    2011-01-01

    very little expression of these anomalies. hardware from the human-occupied area may limit (although not likely eliminate) external materials in the human habitat. Definition of design-to requirements is critical to understanding technical feasibility and costs. The definition of Planetary Protection needs in relation to EVA mission and system element development cost impacts should be considered and interpreted in terms of Plausible Protection criteria. Since EVA operations will have the most direct physical interaction with the Martian surface, PP needs should be considered in the terms of mitigating hardware and operations impacts and costs.

  9. Status of Electrical Actuator Applications

    NASA Technical Reports Server (NTRS)

    Roth, Mary Ellen; Taylor, Linda M.; Hansen, Irving G.

    1996-01-01

    An ever increasing number of actuation functions historically performed by hydraulics or pneumatics are being accomplished by electric actuation. If 'end to end' systems are considered, electric actuators (EA's) are potentially lighter and more efficient. In general, system redundancies may be more easily implemented and operationally monitored. Typically, electrical components exhibit longer mean times to failure and projected lifetime costs of EA's are potentially much lower than those of other options. EA's have certain characteristics which must be considered in their application. The actual mechanical loadings must be established, for the more easily controlled EA may be operated much closer to its full capabilities. At higher rates of motion, EA's are operating as constant power devices. Therefore, it may be possible to start a movement that can not be stopped. The incorporation of high power electronics into remote locations introduces new concerns of EMI and thermal control. It is the management of these and other characteristics that forms the engineering design challenges. Work is currently in progress on EA's for aircraft and expendable launch vehicles. These applications span from ten to 40+ horsepower. The systematics and status of these actuators will be reported along with current technical trends in this area.

  10. Comprehensive piezoceramic actuator review

    NASA Astrophysics Data System (ADS)

    Taylor, Chris J.; Washington, Gregory N.

    2002-07-01

    Piezoceramic actuation has become an area of increased interest in the past ten years. Having been used for many years as sensors in such applications as pressure transducers and smoke detectors, piezoceramics are now being used as prime movers in fuel injectors and valve lifters. In an effort to aid the engineering community, this paper will conduct a comprehensive review of several piezoceramic actuators. Classical design parameters will be derived for each actuator such as blocked force and free stroke. In addition, more esoteric entities such as mechanical efficiency and energy density will also be derived. The result will be design metrics of popular piezoceramic actuators containing vital design equations, validated with empirical data. Of the many different configurations of piezoceramic actuators, this paper will investigate the bimorph and unimorph bender. These actuator types are finding increased use in semi-active structural damping, energy harvesting and vibration control. The work in this paper will show experimental verification of various actuator types as well as theoretical derivations. In addition to unimorphs, bimorphs and stack actuators a novel type of unimorph bender, the THUNDER actuator (developed and licensed by NASA) will be included in the review.

  11. 46 CFR 153.460 - Fire protection systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Fire protection systems. 153.460 Section 153.460... Requirements for Flammable Or Combustible Cargoes § 153.460 Fire protection systems. Each self-propelled ship... riser, each part of a cargo containment system exposed on the weatherdeck must be covered by the...

  12. 14 CFR 25.1093 - Induction system icing protection.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Induction system icing protection. 25.1093... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Induction System § 25.1093 Induction system icing protection. (a) Reciprocating engines. Each reciprocating engine air induction...

  13. Ceramic-Fibrous-Insulation Thermal-Protection System

    NASA Technical Reports Server (NTRS)

    Leiser, Daniel; Churchward, Rex; Katvala, Victor; Stewart, David; Balter, Aliza

    1992-01-01

    New composite thermal-protection system developed in which glass-ceramic impregnated into surface of fibrous insulation. Called TUFI for toughened unipiece fibrous insulation developed as replacement for tiles with reaction-cured-glass (RCG) coating. Impregnation of glass-ceramic results in thermal protection system with insulating properties comparable to existing system but with 20 to 100 times more resistance to impact.

  14. 14 CFR 29.954 - Fuel system lightning protection.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Fuel system lightning protection. 29.954... lightning protection. The fuel system must be designed and arranged to prevent the ignition of fuel vapor within the system by— (a) Direct lightning strikes to areas having a high probability of...

  15. 14 CFR 29.954 - Fuel system lightning protection.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Fuel system lightning protection. 29.954... lightning protection. The fuel system must be designed and arranged to prevent the ignition of fuel vapor within the system by— (a) Direct lightning strikes to areas having a high probability of...

  16. 14 CFR 25.954 - Fuel system lightning protection.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Fuel system lightning protection. 25.954... lightning protection. The fuel system must be designed and arranged to prevent the ignition of fuel vapor within the system by— (a) Direct lightning strikes to areas having a high probability of...

  17. 14 CFR 25.954 - Fuel system lightning protection.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Fuel system lightning protection. 25.954... lightning protection. The fuel system must be designed and arranged to prevent the ignition of fuel vapor within the system by— (a) Direct lightning strikes to areas having a high probability of...

  18. 14 CFR 27.954 - Fuel system lightning protection.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Fuel system lightning protection. 27.954... lightning protection. The fuel system must be designed and arranged to prevent the ignition of fuel vapor within the system by— (a) Direct lightning strikes to areas having a high probability of...

  19. 14 CFR 27.954 - Fuel system lightning protection.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Fuel system lightning protection. 27.954... lightning protection. The fuel system must be designed and arranged to prevent the ignition of fuel vapor within the system by— (a) Direct lightning strikes to areas having a high probability of...

  20. 14 CFR 27.954 - Fuel system lightning protection.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Fuel system lightning protection. 27.954... lightning protection. The fuel system must be designed and arranged to prevent the ignition of fuel vapor within the system by— (a) Direct lightning strikes to areas having a high probability of...

  1. 14 CFR 29.954 - Fuel system lightning protection.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Fuel system lightning protection. 29.954... lightning protection. The fuel system must be designed and arranged to prevent the ignition of fuel vapor within the system by— (a) Direct lightning strikes to areas having a high probability of...

  2. 14 CFR 25.954 - Fuel system lightning protection.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Fuel system lightning protection. 25.954... lightning protection. The fuel system must be designed and arranged to prevent the ignition of fuel vapor within the system by— (a) Direct lightning strikes to areas having a high probability of...

  3. 14 CFR 25.954 - Fuel system lightning protection.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Fuel system lightning protection. 25.954... lightning protection. The fuel system must be designed and arranged to prevent the ignition of fuel vapor within the system by— (a) Direct lightning strikes to areas having a high probability of...

  4. 14 CFR 27.954 - Fuel system lightning protection.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Fuel system lightning protection. 27.954... lightning protection. The fuel system must be designed and arranged to prevent the ignition of fuel vapor within the system by— (a) Direct lightning strikes to areas having a high probability of...

  5. 14 CFR 29.954 - Fuel system lightning protection.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Fuel system lightning protection. 29.954... lightning protection. The fuel system must be designed and arranged to prevent the ignition of fuel vapor within the system by— (a) Direct lightning strikes to areas having a high probability of...

  6. Mechanical properties of thermal protection system materials.

    SciTech Connect

    Hardy, Robert Douglas; Bronowski, David R.; Lee, Moo Yul; Hofer, John H.

    2005-06-01

    An experimental study was conducted to measure the mechanical properties of the Thermal Protection System (TPS) materials used for the Space Shuttle. Three types of TPS materials (LI-900, LI-2200, and FRCI-12) were tested in 'in-plane' and 'out-of-plane' orientations. Four types of quasi-static mechanical tests (uniaxial tension, uniaxial compression, uniaxial strain, and shear) were performed under low (10{sup -4} to 10{sup -3}/s) and intermediate (1 to 10/s) strain rate conditions. In addition, split Hopkinson pressure bar tests were conducted to obtain the strength of the materials under a relatively higher strain rate ({approx}10{sup 2} to 10{sup 3}/s) condition. In general, TPS materials have higher strength and higher Young's modulus when tested in 'in-plane' than in 'through-the-thickness' orientation under compressive (unconfined and confined) and tensile stress conditions. In both stress conditions, the strength of the material increases as the strain rate increases. The rate of increase in LI-900 is relatively small compared to those for the other two TPS materials tested in this study. But, the Young's modulus appears to be insensitive to the different strain rates applied. The FRCI-12 material, designed to replace the heavier LI-2200, showed higher strengths under tensile and shear stress conditions. But, under a compressive stress condition, LI-2200 showed higher strength than FRCI-12. As far as the modulus is concerned, LI-2200 has higher Young's modulus both in compression and in tension. The shear modulus of FRCI-12 and LI-2200 fell in the same range.

  7. Space vehicle integrated thermal protection/structural/meteoroid protection system, volume 1

    NASA Technical Reports Server (NTRS)

    Bartlett, D. H.; Zimmerman, D. K.

    1973-01-01

    A program was conducted to determine the merit of a combined structure/thermal meteoroid protection system for a cryogenic vehicle propulsion module. Structural concepts were evaluated to identify least weight designs. Thermal analyses determined optimum tank arrangements and insulation materials. Meteoroid penetration experiments provided data for design of protection systems. Preliminary designs were made and compared on the basis of payload capability. Thermal performance tests demonstrated heat transfer rates typical for the selected design. Meteoroid impact tests verified the protection characteristics. A mockup was made to demonstrate protection system installation. The best design found combined multilayer insulation with a truss structure vehicle body. The multilayer served as the thermal/meteoroid protection system.

  8. Self-actuated nuclear reactor shutdown system using induction pump to facilitate sensing of core coolant temperature

    DOEpatents

    Sievers, Robert K.; Cooper, Martin H.; Tupper, Robert B.

    1987-01-01

    A self-actuated shutdown system incorporated into a reactivity control assembly in a nuclear reactor includes pumping means for creating an auxiliary downward flow of a portion of the heated coolant exiting from the fuel assemblies disposed adjacent to the control assembly. The shutdown system includes a hollow tubular member which extends through the outlet of the control assembly top nozzle so as to define an outer annular flow channel through the top nozzle outlet separate from an inner flow channel for primary coolant flow through the control assembly. Also, a latching mechanism is disposed in an inner duct of the control assembly and is operable for holding absorber bundles in a raised position in the control assembly and for releasing them to drop them into the core of the reactor for shutdown purposes. The latching mechanism has an inner flow passage extending between and in flow communication with the absorber bundles and the inner flow channel of the top nozzle for accommodating primary coolant flow upwardly through the control assembly. Also, an outer flow passage separate from the inner flow passage extends through the latching mechanism between and in flow communication with the inner duct and the outer flow channel of the top nozzle for accommodating inflow of a portion of the heated coolant from the adjacent fuel assemblies. The latching mechanism contains a magnetic material sensitive to temperature and operable to cause mating or latching together of the components of the latching mechanism when the temperature sensed is below a known temperature and unmating or unlatching thereof when the temperature sensed is above a given temperature. The temperature sensitive magnetic material is positioned in communication with the heated coolant flow through the outer flow passage for directly sensing the temperature thereof. Finally, the pumping means includes a jet induction pump nozzle and diffuser disposed adjacent the bottom nozzle of the control assembly

  9. Thermal Protection System Development, Testing and Qualification

    NASA Astrophysics Data System (ADS)

    Venkatapathy, Ethiraj; Arnold, James; Laub, B.; Hartman, G. J.

    The science community currently has interest in planetary entry probe missions to improve our understanding of the atmospheres of Saturn and Venus [1,2]. As in the case of the Galileo entry probe, such data are critical to the understanding of not only the individual planets but also to further knowledge regarding the formation of the solar system. It is believed that Saturn probes to depths corresponding to 10 bars will be sufficient [1] to provide the desired scientific data. The heating rates for the "shallow" Saturn probes and Venus are in the range of 2 - 5KW/cm2 . It is clear that new, mid-density Thermal Protection System (TPS) materials for such probes can be mission-enabling for mass efficiency [3] and also make the use of smaller vehicles possible from advancements in scientific instrumentation [4]. Past consideration of new Jovian multiprobe missions has been considered problematic without the Giant Planet Arcjet Facility that was used to qualify Carbon Phenolic for the Galileo Probe. This paper describes emerging TPS technology and the proposed use of an affordable, small 5 MW arc jet that can be used for TPS development in test gases appropriate for the aforementioned, new planetary probe applications. Emerging TPS technologies of interest include a mid-density, chopped molded carbon phenolic (CMCP) material around 0.8g/cc and a densified variant of phenolic impregnated carbon ablator (PICA) around 0.5g/cc. The small 5 MW arc jet facility, called the Development Arcjet Facility (DAF) and the methodology of testing TPS, both based on previous work, are discussed. Finally, the applications to Earth entry appropriate to speeds greater than lunar return (11km/s) are discussed as will facility-to-facility validation using air as a test gas. The use of other facilities for development, qualification and certification of TPS for Saturn and Venus is also discussed. [1] Atreya, S. K., et. al. Formation of Giant Planets and Their Atmospheres: Entry Probes for

  10. Robust model reference adaptive output feedback tracking for uncertain linear systems with actuator fault based on reinforced dead-zone modification.

    PubMed

    Bagherpoor, H M; Salmasi, Farzad R

    2015-07-01

    In this paper, robust model reference adaptive tracking controllers are considered for Single-Input Single-Output (SISO) and Multi-Input Multi-Output (MIMO) linear systems containing modeling uncertainties, unknown additive disturbances and actuator fault. Two new lemmas are proposed for both SISO and MIMO, under which dead-zone modification rule is improved such that the tracking error for any reference signal tends to zero in such systems. In the conventional approach, adaption of the controller parameters is ceased inside the dead-zone region which results tracking error, while preserving the system stability. In the proposed scheme, control signal is reinforced with an additive term based on tracking error inside the dead-zone which results in full reference tracking. In addition, no Fault Detection and Diagnosis (FDD) unit is needed in the proposed approach. Closed loop system stability and zero tracking error are proved by considering a suitable Lyapunov functions candidate. It is shown that the proposed control approach can assure that all the signals of the close loop system are bounded in faulty conditions. Finally, validity and performance of the new schemes have been illustrated through numerical simulations of SISO and MIMO systems in the presence of actuator faults, modeling uncertainty and output disturbance.

  11. Structural Analysis of Lightning Protection System for New Launch Vehicle

    NASA Technical Reports Server (NTRS)

    Cope, Anne; Moore, Steve; Pruss, Richard

    2008-01-01

    This project includes the design and specification of a lightning protection system for Launch Complex 39 B (LC39B) at Kennedy Space Center, FL in support of the Constellation Program. The purpose of the lightning protection system is to protect the Crew Launch Vehicle (CLV) or Cargo Launch Vehicle (CaLV) and associated launch equipment from direct lightning strikes during launch processing and other activities prior to flight. The design includes a three-tower, overhead catenary wire system to protect the vehicle and equipment on LC39B as described in the study that preceded this design effort: KSC-DX-8234 "Study: Construct Lightning Protection System LC3 9B". The study was a collaborative effort between Reynolds, Smith, and Hills (RS&H) and ASRC Aerospace (ASRC), where ASRC was responsible for the theoretical design and risk analysis of the lightning protection system and RS&H was responsible for the development of the civil and structural components; the mechanical systems; the electrical and grounding systems; and the siting of the lightning protection system. The study determined that a triangular network of overhead catenary cables and down conductors supported by three triangular free-standing towers approximately 594 ft tall (each equipped with a man lift, ladder, electrical systems, and communications systems) would provide a level of lightning protection for the Constellation Program CLV and CaLV on Launch Pad 39B that exceeds the design requirements.

  12. Nuclear radiation actuated valve

    DOEpatents

    Christiansen, David W.; Schively, Dixon P.

    1985-01-01

    A nuclear radiation actuated valve for a nuclear reactor. The valve has a valve first part (such as a valve rod with piston) and a valve second part (such as a valve tube surrounding the valve rod, with the valve tube having side slots surrounding the piston). Both valve parts have known nuclear radiation swelling characteristics. The valve's first part is positioned to receive nuclear radiation from the nuclear reactor's fuel region. The valve's second part is positioned so that its nuclear radiation induced swelling is different from that of the valve's first part. The valve's second part also is positioned so that the valve's first and second parts create a valve orifice which changes in size due to the different nuclear radiation caused swelling of the valve's first part compared to the valve's second part. The valve may be used in a nuclear reactor's core coolant system.

  13. Multilayer Piezoelectric Stack Actuator Characterization

    NASA Technical Reports Server (NTRS)

    Sherrit, Stewart; Jones, Christopher M.; Aldrich, Jack B.; Blodget, Chad; Bao, Xioaqi; Badescu, Mircea; Bar-Cohen, Yoseph

    2008-01-01

    Future NASA missions are increasingly seeking to use actuators for precision positioning to accuracies of the order of fractions of a nanometer. For this purpose, multilayer piezoelectric stacks are being considered as actuators for driving these precision mechanisms. In this study, sets of commercial PZT stacks were tested in various AC and DC conditions at both nominal and extreme temperatures and voltages. AC signal testing included impedance, capacitance and dielectric loss factor of each actuator as a function of the small-signal driving sinusoidal frequency, and the ambient temperature. DC signal testing includes leakage current and displacement as a function of the applied DC voltage. The applied DC voltage was increased to over eight times the manufacturers' specifications to investigate the correlation between leakage current and breakdown voltage. Resonance characterization as a function of temperature was done over a temperature range of -180C to +200C which generally exceeded the manufacturers' specifications. In order to study the lifetime performance of these stacks, five actuators from one manufacturer were driven by a 60volt, 2 kHz sine-wave for ten billion cycles. The tests were performed using a Lab-View controlled automated data acquisition system that monitored the waveform of the stack electrical current and voltage. The measurements included the displacement, impedance, capacitance and leakage current and the analysis of the experimental results will be presented.

  14. SMA actuators for morphing wings

    NASA Astrophysics Data System (ADS)

    Brailovski, V.; Terriault, P.; Georges, T.; Coutu, D.

    An experimental morphing laminar wing was developed to prove the feasibility of aircraft fuel consumption reduction through enhancement of the laminar flow regime over the wing extrados. The morphing wing prototype designed for subsonic cruise flight conditions (Mach 0.2 … 0.3; angle of attack - 1 … +2∘), combines three principal subsystems: (1) flexible extrados, (2) rigid intrados and (3) an actuator group located inside the wing box. The morphing capability of the wing relies on controlled deformation of the wing extrados under the action of shape memory alloys (SMA) actuators. A coupled fluid-structure model of the morphing wing was used to evaluate its mechanical and aerodynamic performances in different flight conditions. A 0.5 m chord and 1 m span prototype of the morphing wing was tested in a subsonic wind tunnel. In this work, SMA actuators for morphing wings were modeled using a coupled thermo-mechanical finite element model and they were windtunnel validated. If the thermo-mechanical model of SMA actuators presented in this work is coupled with the previously developed structureaerodynamic model of the morphing wing, it could serve for the optimization of the entire morphing wing system.

  15. Active Damping Using Distributed Anisotropic Actuators

    NASA Technical Reports Server (NTRS)

    Schiller, Noah H.; Cabell, Randolph H.; Quinones, Juan D.; Wier, Nathan C.

    2010-01-01

    A helicopter structure experiences substantial high-frequency mechanical excitation from powertrain components such as gearboxes and drive shafts. The resulting structure-borne vibration excites the windows which then radiate sound into the passenger cabin. In many cases the radiated sound power can be reduced by adding damping. This can be accomplished using passive or active approaches. Passive treatments such as constrained layer damping tend to reduce window transparency. Therefore this paper focuses on an active approach utilizing compact decentralized control units distributed around the perimeter of the window. Each control unit consists of a triangularly shaped piezoelectric actuator, a miniature accelerometer, and analog electronics. Earlier work has shown that this type of system can increase damping up to approximately 1 kHz. However at higher frequencies the mismatch between the distributed actuator and the point sensor caused control spillover. This paper describes new anisotropic actuators that can be used to improve the bandwidth of the control system. The anisotropic actuators are composed of piezoelectric material sandwiched between interdigitated electrodes, which enables the application of the electric field in a preferred in-plane direction. When shaped correctly the anisotropic actuators outperform traditional isotropic actuators by reducing the mismatch between the distributed actuator and point sensor at high frequencies. Testing performed on a Plexiglas panel, representative of a helicopter window, shows that the control units can increase damping at low frequencies. However high frequency performance was still limited due to the flexible boundary conditions present on the test structure.

  16. Biomimetic photo-actuation: progress and challenges

    NASA Astrophysics Data System (ADS)

    Dicker, Michael P. M.; Weaver, Paul M.; Rossiter, Jonathan M.; Bond, Ian P.; Faul, Charl F. J.

    2016-04-01

    Photo-actuation, such as that observed in the reversible sun-tracking movements of heliotropic plants, is produced by a complex, yet elegant series of processes. In the heliotropic leaf movements of the Cornish Mallow, photo-actuation involves the generation, transport and manipulation of chemical signals from a distributed network of sensors in the leaf veins to a specialized osmosis driven actuation region in the leaf stem. It is theorized that such an arrangement is both efficient in terms of materials use and operational energy conversion, as well as being highly robust. We concern ourselves with understanding and mimicking these light driven, chemically controlled actuating systems with the aim of generating intelligent structures which share the properties of efficiency and robustness that are so important to survival in Nature. In this work we present recent progress in mimicking these photo-actuating systems through remote light exposure of a metastable state photoacid and the resulting signal and energy transfer through solution to a pH-responsive hydrogel actuator. Reversible actuation strains of 20% were achieved from this arrangement, with modelling then employed to reveal the critical influence hydrogel pKa has on this result. Although the strong actuation achieved highlights the progress that has been made in replicating the principles of biomimetic photo-actuation, challenges such as photoacid degradation were also revealed. It is anticipated that current work can directly lead to the development of high-performance and low-cost solartrackers for increased photovoltaic energy capture and to the creation of new types of intelligent structures employing chemical control systems.

  17. Simulated dynamic response of a servovalve controlled hydraulic actuator

    NASA Technical Reports Server (NTRS)

    Babcock, Dale A.

    1990-01-01

    A general purpose math model of a servovalve controlled hydraulic actuator system is derived. The system consists of a linear actuator with unequal piston areas, a single stage servovalve, a gas charged hydraulic accumulator, and the interconnecting piping. The state equations are integrated using the Advanced Continuous Simulation Language (ACSL) for determining the system's dynamic response characteristics. Using this generalized hydraulic actuator system model, response characteristics were determined for various servovalve commands.

  18. Novel Directional Protection Scheme for the FREEDM Smart Grid System

    NASA Astrophysics Data System (ADS)

    Sharma, Nitish

    This research primarily deals with the design and validation of the protection system for a large scale meshed distribution system. The large scale system simulation (LSSS) is a system level PSCAD model which is used to validate component models for different time-scale platforms, to provide a virtual testing platform for the Future Renewable Electric Energy Delivery and Management (FREEDM) system. It is also used to validate the cases of power system protection, renewable energy integration and storage, and load profiles. The protection of the FREEDM system against any abnormal condition is one of the important tasks. The addition of distributed generation and power electronic based solid state transformer adds to the complexity of the protection. The FREEDM loop system has a fault current limiter and in addition, the Solid State Transformer (SST) limits the fault current at 2.0 per unit. Former students at ASU have developed the protection scheme using fiber-optic cable. However, during the NSF-FREEDM site visit, the National Science Foundation (NSF) team regarded the system incompatible for the long distances. Hence, a new protection scheme with a wireless scheme is presented in this thesis. The use of wireless communication is extended to protect the large scale meshed distributed generation from any fault. The trip signal generated by the pilot protection system is used to trigger the FID (fault isolation device) which is an electronic circuit breaker operation (switched off/opening the FIDs). The trip signal must be received and accepted by the SST, and it must block the SST operation immediately. A comprehensive protection system for the large scale meshed distribution system has been developed in PSCAD with the ability to quickly detect the faults. The validation of the protection system is performed by building a hardware model using commercial relays at the ASU power laboratory.

  19. Structural characteristics of the shuttle orbiter ceramic thermal protection system

    NASA Technical Reports Server (NTRS)

    Cooper, P. A.

    1982-01-01

    The thermal protection system (TPS) of the Space Shuttle Orbiter is described as well as the results of dynamic reponse studies conducted in support of the efforts to certify the TPS for flight. The ceramic Thermal Protection System consists of ceramic tiles bonded to felt pads which are in turn bonded to the Orbiter substructure to protect the aluminum substructure from the heat of reentry.

  20. Lock for hydraulic actuators

    NASA Technical Reports Server (NTRS)

    Wood, R. H.

    1981-01-01

    Two clamps hold rod in fixed extension from cylinder even when power is off, converting actuator into stiff structural member. Locked actuator is useful as mechanical support or linkage or as fail-safe device in case of loss of hydraulic pressure. Potential applications include manufacturing processes and specialized handling and holding devices.