Science.gov

Sample records for actuating systems

  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. Thermally actuated mechanical systems

    NASA Astrophysics Data System (ADS)

    Sul, Onejae

    This thesis will discuss the generation of controlled sub-micron motions using novel micro actuators. Our research focuses on the development of an arm-type actuator and a free-motion locomotive walking device. Nano-science and nano-technology focuses on the creation of novel functional materials and also at the development of new fabrication techniques incorporating them. In the fields of novel fabrication techniques, manipulations of micron or sub-micron objects by micro actuators have been suggested in the science and engineering societies for mainly two reasons. From a scientific standpoint, new tools enable new prospective sciences, as is evident from the development of the atomic force microscope. From an engineering standpoint, the miniaturization of manipulation tools will require less material and less energy during a material's production. In spite of such importance, progress in the actuator miniaturization is in a primitive state, especially for the micro mobile devices. The thesis will be a key step in pursuit of this goal with an emphasis on generating motions. Our static actuator uses the excellent elastic properties of multiwall carbon nanotubes as a template for a bimorph system. Deflections in response to temperature variations are demonstrated. The mobile device itself is a bimorph system consisting of thin metal films. Control mechanisms for its velocity and steering are discussed. Finally, fundamental limits on the capabilities of the two devices in a more general sense are discussed under via laws of physics.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Actuators For A Segmented Mirror Control System

    NASA Astrophysics Data System (ADS)

    Gabor, George

    1983-11-01

    The active control of segmented mirrors requires actuators to move the segments in response to perturbations. Each segment of the University of California Ten Meter Telescope has three of its six rigid-body degrees of freedom actively controlled; piston and tilt about two axes. The system design requires the actuator to carry a load that varies as the telescope moves from zenith to horizon. The maximum load is one third of the segment mass, about 150kg. The system design also needs actuator adjustment resolution less than 20nm over a range of 3mm with a 2µm/sec response rate. Actuators which satisfy these requirements have been designed, built, and tested. A torque motor turns a screw shaft whose axial load is taken by a roller thrust bearing. Simultaneously the screw drives a roller nut to position the mirror segment. The roller screw converts rotary to linear motion with nanometer smoothness over a large dynamic range. A stick-slip behavior in the thrust bearing makes the mechanical system non-linear for small motions. Each actuator has a microprocessor-controlled servo loop and the servo loop algorithm compensates for this non-linear behavior. The actuator design and servo loop algorithm are described and the results of servo loop performance tests are given.

  17. Actuators for a segmented mirror control system.

    NASA Astrophysics Data System (ADS)

    Gabor, George

    1984-01-01

    The active control of segmented mirrors requires actuators to move the segments in response to perturbations. Each segment of the University of California Ten Meter Telescope has three of its six rigid-body degrees of freedom actively controlled; piston and tilt about two axes. The system design requires the actuator to carry a load that varies as the telescope moves from zenith to horizon. The maximum load is one third of the segment mass, about 150kg. The system design also needs actuator adjustment resolution less than 20nm over a range of 3mm with a 2 m/sec response rate. Actuators which satisfy these requirements have been designed, built, and tested. A torque motor turns a screw shaft whose axial load is taken by a roller thrust bearing. Simultaneously the screw drives a roller nut to position the mirror segment. The roller screw converts rotary to linear motion with nanometer smoothness over a large dynamic range. A stick-slip behavior in the thrust bearing makes the mechanical system non-linear for small motions. Each actuator has a microprocessor-controlled servo loop and the servo loop algorithm compensates for this non-linear behavior. The actuator design and servo loop algorithm are described and the results of servo loop performance tests are given.

  18. 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.

  19. 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

  20. 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.

  1. A magnetorheological actuation system: test and model

    NASA Astrophysics Data System (ADS)

    John, Shaju; Chaudhuri, Anirban; Wereley, Norman M.

    2008-04-01

    Self-contained actuation systems, based on frequency rectification of the high frequency motion of an active material, can produce high force and stroke output. Magnetorheological (MR) fluids are active fluids whose rheological properties can be altered by the application of a magnetic field. By using MR fluids as the energy transmission medium in such hybrid devices, a valving system with no moving parts can be implemented and used to control the motion of an output cylinder shaft. The MR fluid based valves are configured in the form of an H-bridge to produce bi-directional motion in an output cylinder by alternately applying magnetic fields in the two opposite arms of the bridge. The rheological properties of the MR fluid are modeled using both Bingham plastic and bi-viscous models. In this study, the primary actuation is performed using a compact terfenol-D rod driven pump and frequency rectification of the rod motion is done using passive reed valves. The pump and reed valve configuration along with MR fluidic valves form a compact hydraulic actuation system. Actuator design, analysis and experimental results are presented in this paper. A time domain model of the actuator is developed and validated using experimental data.

  2. 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.

  3. Update: NASA Pyrotechnically Actuated Systems Program

    NASA Technical Reports Server (NTRS)

    Schulze, Norman R.

    1994-01-01

    This technical report discusses the NASA Pyrotechnically Actuated Systems (PAS) Program. It contains the following three sections: program origin, program description, and summary. The first section, program origin, contains an introduction to pyrotechnic systems and devices and discusses some examples. Section two focuses on the PAS program goals, program flow, and PAS programs organization. And section three gives a overall summary of the program.

  4. 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.

  5. 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.

  6. 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...

  7. 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.

  8. 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.

  9. Requirement analysis of an intelligent, redundant, actuation system

    NASA Technical Reports Server (NTRS)

    De Feo, P.; Shih, K. C.

    1986-01-01

    The reliability and fault tolerance requirements of integrated, critical, digital fly-by-wire control systems for advanced military and civil aircraft requires redundant, reconfigurable implementations of the actuation system. An effective way for controlling the actuators and implementing the required fault detection and reconfiguration strategies is by means of dedicated microprocessors. This paper describes a laboratory implementation of a flexible intelligent redundant actuation system capable of demonstrating the concept and analyzing a variety of configurations and technical issues.

  10. 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.

  11. 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.

  12. 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.

  13. Configuration of a shear web based actuation system

    NASA Astrophysics Data System (ADS)

    Natterer, Franz Josef; Monner, Hans-Peter

    2010-04-01

    Shape adaptive systems and structural configurations are necessary to fulfill the demands of a future unmanned aerial vehicle structure. Predominantly the present approaches are based on a passive load-bearing structure having smart actuation systems deforming the passive structural configuration elastically in the wanted shape. Therefore the actuation system can be based on discrete actuators, like electrically driven motors using gearing systems to transform the displacement into the structure or on smart material configurations placed on the load bearing passive structure, deforming the structure within the elastic region into the wanted shape. Using smart materials within load-bearing structures, elastic and static strength properties vary between passive and active structures. Matching these properties is a great challenge for future structural configurations. This is a successful approach for certain applications, e.g. smart rotor blade. The availability of two-dimensional smart actuator configurations with distinct actuation orientation allows the definition of a distinct load bearing active structure. Therefore the so called "web" of a spar-equivalent configuration was substituted by such a smart material actuator also known as macro fiber composite (MFC). Activating the web of the active cantilevered spar-configuration is resulting in a free end displacement. The main advantage lies in the fact that this approach will allow larger active displacements in comparison to a passive structural configuration with applied smart material actuators. Within the paper the process of developing the shear web based actuation system with configuration details will be illustrated and future steps will be proposed.

  14. 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

  15. 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.

  16. Design and demonstration of a fish robot actuated by a SMA-driven actuation system

    NASA Astrophysics Data System (ADS)

    Le, Chan H.; Nguyen, Quang S.; Park, Hoon C.

    2010-04-01

    This paper presents a concept of a fish robot actuated by an SMA-based actuator. The bending-type actuator system is composed of a 0.1mm diameter SMA wire and a 0.5mm thick glass/epoxy strip. The SMA wire is installed to the bent composite strip. The actuator can produce about 200gf of blocking force and 3.5mm displacement at the center of the glass/epoxy strip. The bending motion of the actuator is converted into the tail-beat motion of a fish robot through a linkage system. The fish robot is evaluated by measuring the tail-beat angle, swimming speed and thrust produced by the fish robot. The tail-beat angle is about 20° and the maximum swimming speed is about 1.6cm/s. The measured thrust is about 0.4gf when the fish robot is operated at 0.9Hz.

  17. 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.

  18. 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.

  19. 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.

  20. 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. PMID:26320957

  1. A jellyfish-like swimming mini-robot actuated by an electromagnetic actuation system

    NASA Astrophysics Data System (ADS)

    Ko, Youngho; Na, Sungyoung; Lee, Youngwoo; Cha, Kyoungrae; Ko, Seong Young; Park, Jongoh; Park, Sukho

    2012-05-01

    Among the various kinds of actuations for biomimetic robots, the electromagnetic actuation (EMA) method has been regarded as the one with the most potential. This paper proposes a jellyfish-like swimming mini-robot actuated by an EMA system in three-dimensional (3D) space. The jellyfish-like mini-robot has four flexible fins, each of which is equipped with a permanent magnet for electromagnetic actuation; the robot’s body is 17 mm long and 0.5 mm thick. Our EMA system was able to generate a uniform magnetic field in a desired direction in 3D space, which could bend the fins of the jellyfish-like mini-robot. Therefore, a cyclic change in the uniform magnetic field, in the EMA system, would synchronize the fluctuation of the fins and could generate a propulsion force for the robot, in the desired direction. In order to maximize the propulsion force of the jellyfish-like mini-robot, the waveform and frequency of the input current in the EMA system are optimized. Consequently, our jellyfish-like mini-robot was able to generate maximum propulsion force when a square waveform input current (13 A magnitude and 10 Hz frequency) was applied to the EMA system. Finally, the jellyfish-like mini-robot with the EMA system was able to perform various 3D swimming motions.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. A soft actuation system for segmented reflector articulation and isolation

    NASA Technical Reports Server (NTRS)

    Agronin, Michael L.; Jandura, Louise

    1990-01-01

    Segmented reflectors have been proposed for space based applications such as optical communication and large diameter telescopes. An actuation system for mirrors in a space based segmented mirror array was developed as part of NASA's Precision Segmented Reflector program. The actuation system, called the Articulated Panel Module (APM), provides 3 degrees of freedom mirror articulation, gives isolation from structural motion, and simplifies space assembly of the mirrors to the reflector backup truss. A breadboard of the APM was built and is described.

  7. 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.

  8. 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.

  9. 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.

  10. Two-stage actuation system using DC motors and piezoelectric actuators for controllable industrial and automotive brakes and clutches

    NASA Astrophysics Data System (ADS)

    Neelakantan, Vijay A.; Washington, Gregory N.; Bucknor, Norman K.

    2005-05-01

    High bandwidth actuation systems that are capable of simultaneously producing relatively large forces and displacements are required for use in automobiles and other industrial applications. Conventional hydraulic actuation mechanisms used in automotive brakes and clutches are complex, inefficient and have poor control robustness. These lead to reduced fuel economy, controllability issues and other disadvantages. This paper involves the design, development, testing and control of a two-stage hybrid actuation mechanism by combining classical actuators like DC motors and advanced smart material actuators like piezoelectric actuators. The paper also discusses the development of a robust control methodology using the Internal Model Control (IMC) principle and emphasizes the robustness property of this control methodology by comparing and studying simulation and experimental results.

  11. 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.

  12. 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.

  13. Control of Systems With Slow Actuators Using Time Scale Separation

    NASA Technical Reports Server (NTRS)

    Stepanyan, Vehram; Nguyen, Nhan

    2009-01-01

    This paper addresses the problem of controlling a nonlinear plant with a slow actuator using singular perturbation method. For the known plant-actuator cascaded system the proposed scheme achieves tracking of a given reference model with considerably less control demand than would otherwise result when using conventional design techniques. This is the consequence of excluding the small parameter from the actuator dynamics via time scale separation. The resulting tracking error is within the order of this small parameter. For the unknown system the adaptive counterpart is developed based on the prediction model, which is driven towards the reference model by the control design. It is proven that the prediction model tracks the reference model with an error proportional to the small parameter, while the prediction error converges to zero. The resulting closed-loop system with all prediction models and adaptive laws remains stable. The benefits of the approach are demonstrated in simulation studies and compared to conventional control approaches.

  14. 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.

  15. 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.

  16. 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.

  17. Electromechanical Simulation of Actively Controlled Rotordynamic Systems with Piezoelectric Actuators

    NASA Technical Reports Server (NTRS)

    Lin, Reng Rong; Palazzolo, A. B.; Kascak, A. F.; Montague, G.

    1991-01-01

    Theories and tests for incorporating piezoelectric pushers as actuator devices for active vibration control are discussed. It started from a simple model with the assumption of ideal pusher characteristics and progressed to electromechanical models with nonideal pushers. Effects on system stability due to the nonideal characteristics of piezoelectric pushers and other elements in the control loop were investigated.

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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.

  3. A description of model 3B of the multipurpose ventricular actuating system. [providing controlled driving pressures

    NASA Technical Reports Server (NTRS)

    Webb, J. A., Jr.

    1974-01-01

    The multipurpose ventricular actuating system is a pneumatic signal generating device that provides controlled driving pressures for actuating pulsatile blood pumps. Overall system capabilities, the timing circuitry, and calibration instruction are included.

  4. An improved flapping wing system actuated by the LIPCA

    NASA Astrophysics Data System (ADS)

    Syaifuddin, Moh.; Park, Hoon C.; Lee, Sang K.; Byun, Do Y.

    2006-03-01

    This paper presents an improved version of the insect-mimicking flapping-wing mechanism actuated by LIPCA (Lightweight Piezo-Composite Actuator). As the previous version, the actuation displacement of the actuator is converted into flapping-wing motion by a mechanical linkage system that functioned as displacement amplifier as well. In order to provide feathering motion, the wing is attached to the axis through a hinge system that allows the wing rotation at each end of half-stroke, due to air resistance. In this improved version, the total weight has been reduced to the half of the previous one. The device could produce about 90 degree of flapping angle when it operated at around 10 Hz, which was the natural flapping-frequency. Several flapping tests under different parameter configurations were conducted in order to investigate the characteristic of the generated lift. In addition, the smoke-wire test was also conducted, so that the vortices around the wing can be visually observed. Even though the present wing has smaller wing area, it could produce higher lift then before.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

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

    PubMed Central

    Liu, Taoming; Çavuşoğlu, 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

  11. 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

  12. Apollo experience report: Guidance and control systems: CSM service propulsion system gimbal actuators

    NASA Technical Reports Server (NTRS)

    Mcmahon, W. A.

    1975-01-01

    The service propulsion system gimbal actuators of the Apollo command and service module were developed, modified, and qualified between February 1962 and April 1968. The development of these actuators is described as the result of extensive testing, retesting, and modification of the initial design. Successful completion of each mission without anomalies attributable to the actuators indicated that the particular configuration (modification) in use was adequate for the flight profile imposed.

  13. Three-axis lever actuator with flexure hinges for an optical disk system

    NASA Astrophysics Data System (ADS)

    Han, Chang-Soo; Kim, Soo-Hyun

    2002-10-01

    A three-axis lever actuator with a flexure hinge has been designed and fabricated. This actuator is driven by electromagnetic force based on a coil-magnet system and can be used as a high precision actuator and, especially as a pickup head actuator in optical disks. High precision and low sensitivity to external vibration are the major advantages of this lever actuator. An analysis model was found and compared to the finite element method. Dynamic characteristics of the three-axis lever actuator were measured. The results are in very close agreement to those predicted by the model and finite element analysis.

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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.

  20. Piezoceramic multilayer actuators for fuel injection systems in automotive area

    NASA Astrophysics Data System (ADS)

    Schuh, Carsten; Steinkopff, Thorsten; Wolff, Andreas; Lubitz, Karl

    2000-06-01

    Cofired multilayer piezoceramic actuators as extremely fast valve driving elements will lead to a significant progress in the field of fuel injection systems. A careful adaptation of the component performance to the system demands, an extraordinary high reliability, and competitive low production costs are prerequisites for this large-scale industrial application. With proper material selection as basis, conventional multilayer technology has to be substantially extended in order to achieve large stack volumes, to avoid degradation effects during cofiring and nevertheless to meet the target costs. Under large-signal driving conditions, the static and dynamic behavior of the component is essentially influenced by driving pulse shape, clamping force, and stiffness of the load. Linear FE methods are employed to calculate the performance criteria of different actuator designs. Moreover, a FE-implementation using a micromechanical domain switching model was developed in order to describe the strongly nonlinear material behavior. Together with a quantitative estimation of crack initiation and propagation by means of fracture mechanics, these methods can give valuable hits for controlling the effects of fatigue and deterioration which may limit the operating life time. In order to optimize the interaction of the electrical and mechanical parts in the injection system, dynamic models of piezoelectric components must be provided. A nonlinear model of the stack actuator has been developed for the analysis software MATLAB/SIMULINK. Special attention has been paid to the hysteresis properties.

  1. System Dynamics and Control System for a High Bandwidth Rotary Actuator and Fast Tool Servo

    SciTech Connect

    Montesanti, R C; Trumper, D L

    2005-08-05

    This paper explores some of the system dynamics and control issues for a short-stroke rotary actuator that we designed and tested for a new fast tool servo referred to as the 10 kHz rotary fast tool servo. The use of a fast tool servo (FTS) with a diamond turning machine for producing non-axisymmetric or textured surfaces on a workpiece is well known. In a previous paper [1] the authors provide details on the mechanical design and trade-off issues that were considered during the design phase for the fast tool servo. At the heart of that machine is the normal-stress variable reluctance rotary actuator described in more detail in this paper. In addition to producing the torque that is needed for the 10 kHz rotary fast tool servo, the actuator produces a force and is therefore referred to as a hybrid rotary/linear actuator. The actuator uses bias and steering magnetic fluxes for linearizing the torque versus current relationship. Certain types of electric engraving heads use an actuator similar in principle to our hybrid actuator. In the case of the engraving heads, the actuator is used to produce and sustain a resonating mechanical oscillator. This is in sharp contrast to the arbitrary trajectory point-to-point closed-loop control of the tool tip that we demonstrate with our actuator and the 10 kHz FTS. Furthermore, we demonstrate closed-loop control of both the rotary and linear degrees of freedom for our actuator. We provide a brief summary of the demonstrated performance of the 10 kHz rotary fast tool servo, and discuss the magnetic circuit for the actuator and some of the related control issues. Montesanti [2] provides a more detailed and thorough discussion on the 10 kHz rotary fast tool servo, the hybrid actuator, and the pertinent prior art.

  2. 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.

  3. Magnetohydrodynamic actuation of droplets for millimetric planar fluidic systems

    NASA Astrophysics Data System (ADS)

    Ahmadi, A.; McDermid, C. M.; Markley, L.

    2016-01-01

    In this work, a magnetohydrodynamic method is proposed for the actuation of droplets in small-scale planar fluidic systems, providing an alternative to commonly used methods such as electrowetting-on-dielectric. Elementary droplet-based operations, including transport, merging, and mixing, are demonstrated. The forces acting on millimetric droplets are carefully investigated, with a primary focus on the magnetic actuation force and on the unbalanced capillary forces that arise due to hysteresis. A super-hydrophobic channel is 3D printed to guide the droplets, with thin wires installed as contact electrodes and permanent magnets providing a static magnetic field. It is shown that droplet motion is enhanced by increasing the droplet size and minimizing the electrode contact surface. The effects of channel geometry on threshold voltage and minimum moveable droplet volume are characterized. Finally, the presence of electrolysis is investigated and mitigating strategies are discussed.

  4. EAP hydrogels for pulse-actuated cell system (PACS) architectures

    NASA Astrophysics Data System (ADS)

    Plata, R. Erik; Rogers, Hallena R.; Banister, Mark; Vohnout, Sonia; McGrath, Dominic V.

    2007-04-01

    Electroactuated polymer (EAP) hydrogels based on JEFFAMINE® T-403 and ethylene glycol glycidyl ether (EGDGE) are used in an infusion pump based on the proprietary Pulse Actuated Cell System (PACS) architecture in development at Medipacs LLC. We report here significant progress in optimizing the formulation of the EAP hydrogels to dramatically increase hydrolytic stability and reproducibility of actuation response. By adjusting the mole fraction of reactive components of the formulation and substituting higher molecular weight monomers, we eliminated a large degree of the hydrolytic instability of the hydrogels, decreased the brittleness of the gel, and increased the equilibrium swelling ratio. The combination of these two modifications to the formulation resulted in hydrogels that exhibited reproducible swelling and deswelling in response to pH for a total period of 10-15 hours.

  5. 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.

  6. Delocalized pi-electron systems: Towards actuators and switches

    NASA Astrophysics Data System (ADS)

    Almutairi, Adah

    The underlying theme in this dissertation is the study of structure-property relationships of pi-electron systems, and thereby determining the functions that may arise from these properties. We primarily describe our findings on the structure-property relationship of ortho oligo aryls and our proposed application of these helical systems as Single Molecule, or Intrinsic Electromechanical Actuators. Electromechanical actuation (EMA) is the conversion of electrical to mechanical energy. Conducting polymer EMAs (CP-EMAs) are a well-known class of functional conjugated polymers, that can generate up to 100 times more force than natural muscle for a given cross-section, and up to three times the power to mass ratios. Ortho oligo thiophenes, in general, have shown a propensity for helicity, coupled with redox induced dimensional changes that mimic the movement of a spring. We show, as proof of concept, their utility as spring-like Intrinsic Electromechemical Actuators, which function at lower voltages, allowing for higher efficiencies, faster response rates, and higher fatigue resistance.

  7. 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

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. The design and evaluation of a hydraulic actuation system for a legged rough-terrain vehicle

    NASA Astrophysics Data System (ADS)

    Srinivasan, K.; Waldron, K. J.; Dworak, J. A.

    One of the causes of low efficiency of legged vehicles is the type of actuation system used. This paper describes the overall design and the evaluation of some aspects of a proposed hydraulic actuation system for a six-legged vehicle intended for use in rough terrain. Features of the hydraulic actuation system designed to improve mechanical efficiency are described. A combination of linearized dynamic system analysis and computer simulation of the nonlinear dynamic system equations is used to evaluate some aspects of the proposed design. The tradeoff between energy efficient operation and the dynamic performance of the actuation system is investigated. Some criteria for controller design are enumerated.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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

  6. 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.

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

    NASA Astrophysics Data System (ADS)

    1993-05-01

    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.

  8. 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.

  9. New results on switched linear systems with actuator saturation

    NASA Astrophysics Data System (ADS)

    Duan, Chang; Wu, Fen

    2016-04-01

    This paper further studies the analysis and control problems of continuous-time switched linear systems subject to actuator saturation. Using the norm-bounded differential inclusion description of the saturated systems and the minimal switching rule, a set of switched output feedback controllers is designed to minimise the disturbance attenuation level defined by the regional ? gain over a class of energy-bounded disturbances. The synthesis conditions are expressed as bilinear matrix inequalities, and can be solved by numerical search coupled with linear matrix inequality optimisation. Compared to the previous method based on polytopic differential inclusion, the proposed approach has good scalability and potentially renders better performance. Numerical examples are provided to verify the effectiveness of the proposed approach.

  10. 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.

  11. 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.

  12. Concept and Demonstration of Individual Probe Actuation in Two-Dimensional Parallel Atomic Force Microscope System

    NASA Astrophysics Data System (ADS)

    Akiyama, Terunobu; Aeschimann, Laure; Chantada, Laura; de Rooij, Nico. F.; Heinzelmann, Harry; Herzig, Hans P.; Manzardo, Omar; Meister, André; Polesel-Maris, Jérôme; Pugin, Raphaël; Staufer, Urs; Vettiger, Peter

    2007-09-01

    A concept of an array actuator that is used to control the tip-sample separation of cantilevers in a two-dimensional (2D) probe array scanning system is proposed in this article. The feasibility of the concept is demonstrated with a 10× 10 array actuator with 500 μm xy-pitches. The array actuator is made by slicing a bulk piezoceramic block. The obtained maximum actuation of a single probe was 2.19 μmp-p at ± 168 Vp-p. A major issue for the actuator was the insufficient strength of the frame of the probe array chip. The demonstrated array actuator is highly compatible with previously developed parallel readout modules that use either a parallel optical beam or integrated piezoresistive deflection sensing. A large-scale 2D probe array is our ultimate target.

  13. 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.

  14. 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.

  15. 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.

  16. Shape memory system with integrated actuation using embedded particles

    DOEpatents

    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.

  17. 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.

  18. 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.

  19. 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.

  20. Robotic Arm and Rover Actuator Systems for Mars Exploration

    NASA Technical Reports Server (NTRS)

    Reid, L.; Brawn, D.; Noon, D.

    1999-01-01

    Missions such as the Sojourner Rover, the Robotic Arm for Mars Polar Lander, and the 2003 Mars Rover, Athena, use numerous actuators that must operate reliably in extreme environments for long periods of time.

  1. Fault-tolerant control of delta operator systems with actuator saturation and effectiveness loss

    NASA Astrophysics Data System (ADS)

    Yang, Hongjiu; Zhang, Luyang; Zhao, Ling; Yuan, Yuan

    2016-07-01

    This paper studies the problem of robust fault-tolerant control against the actuator effectiveness loss for delta operator systems with actuator saturation. Ellipsoids are used to estimate the domain of attraction for the delta operator systems with actuator saturation and effectiveness loss. Some invariance set conditions used for enlarging the domain of attraction are expressed by linear matrix inequalities. Discussions on system performance optimisation are presented in this paper, including reduction on computational complexity, expansion of the domain of attraction and disturbance rejection. Two numerical examples are given to illustrate the effectiveness of the developed techniques.

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. Optimal actuator and sensor placement in the linearized complex Ginzburg-Landau system

    NASA Astrophysics Data System (ADS)

    Chen, Kevin; Rowley, Clarence

    2010-11-01

    The linearized complex Ginzburg-Landau equation is a model for the evolution of small fluid perturbations, such as in a bluff body wake. We control this system by implementing actuators and sensors and designing an H2-optimal controller. We seek the optimal actuator and sensor placement that minimizes the H2 norm of the controlled system, from flow disturbances to a cost on the perturbation and input magnitude. We formulate the gradient of the H2 squared norm with respect to actuator and sensor positions, and iterate toward the optimal position. With a single actuator and sensor, it is optimal to place the actuator just upstream of the origin (e.g., the bluff body object) and the sensor just downstream. With multiple but an equal number of actuators and sensors, it is optimal to arrange them in pairs, placing actuators slightly upstream of sensors, and scattering pairs throughout the spatial domain. Global mode and Gramian analyses fail to predict the optimal placement; they produce H2 norms about five times higher than at the true optimum. A wave maker formulation is better able to guess an initial condition for the iterator.

  7. 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.

  8. Silicon micromachined pumps employing piezoelectric membrane actuation for microfluidic systems

    NASA Astrophysics Data System (ADS)

    Koch, Michael

    Microsystems technology is a rapidly expanding area that comprises electronics, mechanics and optics. In this field, physical/chemical sensing, fluid handling and optical communication are emerging as potential markets. Microfluidic systems like an implantable insulin pump, a drug delivery system and a total chemical analysis system are currently being developed by academia and industry around the world. This project contributes to the area of microfluidics in that a novel thick-film-on-silicon membrane actuator has been developed to allow inexpensive mass production of micropumps. To date piezoelectric plates have been surface mounted onto a silicon membrane. This single chip fabrication method can now be replaced by screen printing thick piezoelectric layers onto 4 inch silicon substrates. Two different pump types have been developed. These are membrane pumps with either cantilever valves or diffuser/nozzle valves. Pump rates between 100 and 200 μl min-1 and backpressures up to 4 kPa have been achieved with these pumps. Along with the technology of micropumps, simulators have been developed. A novel coupled FEM-CFD solver was realised by a computer controlled coupling of two commercially available packages (ANSYS and CFX-Flow3D). The results of this simulator were in good agreement with measurements on micromachined cantilever valves. CFX- Flow3D was also used to successfully model the behaviour of the diffuser/nozzle valve. Finally, the pump has been simulated using a continuity equation. A behavioural dynamic extension of the cantilever valve was necessary to achieve better prediction of the pump rates for higher frequencies. As well, a common process has been developed for microfluidic devices like micromixers, particle counters and sorters as well as flow sensors. The micromixer has been tested already and achieves mixing for input pressures between 2 and 7 kPa. This agrees with simulations of the diffusive mixing with CFX-Flow3D. Together with the micropump

  9. 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.

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

    NASA Astrophysics Data System (ADS)

    Sundberg, Gale R.

    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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Adaptive dynamic surface control for a class of MIMO nonlinear systems with actuator failures

    NASA Astrophysics Data System (ADS)

    Amezquita S., Kendrick; Yan, Lin; Butt, Waseem A.

    2013-03-01

    In this article, an adaptive dynamic surface control scheme for a class of MIMO nonlinear systems with actuator failures and uncertainties is presented. In the proposed control scheme, the dynamic changes and disturbances induced by actuator failures are detected and isolated by means of radial basis function neural networks, which also compensate system uncertainties that arise from the mismatch between nominal model and real plant. In the presence of unknown actuation functions, the effectiveness of the control scheme is guaranteed by imposing a structural condition on the actuation matrix. Moreover, the singularity problem that arises from the approximation of unknown actuation functions is circumvented, and thus the use parameter projection is avoided. In this work, the nominal plant is transformed into a suitable form via diffeomorphism. Dynamic surface control design technique is used to develop the control laws. The closed-loop signals are proven to be uniformly ultimately bounded through Lyapunov approach, and the output tracking error is shown to be bounded within a residual set which can be made arbitrarily small by appropriately tuning the controller parameters. Finally, the proposed adaptive control scheme effectiveness is verified by simulation of the longitudinal dynamics of a twin otter aircraft undergoing actuator failures.

  17. 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

  18. 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.

  19. 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.

  20. Design of a bidirectional actuator for a nanopositioning system with a permanent magnet and an electromagnet

    NASA Astrophysics Data System (ADS)

    Kim, K. H.; Gweon, D. G.

    2005-12-01

    A precision bidirectional linear actuator for ultraprecision systems is proposed and designed in this article. The actuator is composed of a symmetric structure with a force generation unit and a guide mechanism. The force generation part consists of a permanent magnet and an electromagnet, which generate a permanent and a reversible flux, respectively. The combination of permanent and reversible fluxes makes various flux densities in its air gaps between the moving part and the fixed yokes. The difference between flux densities in the lower and upper gaps creates forces for bidirectional linear motions of hundreds of micrometers. As a guide mechanism, two circular plates and one shaft are used. Reducing other forces generated by motions, except the z-directional motion, these circular plates in the form of a flexure endow the actuator with smooth motion, freedom from wear, and a high stiffness for a rapid settling time. The function of the shaft is to transfer motion to an object. Finally, the total body has a symmetric structure enabling it to be stable in terms of thermal error. The actuator is designed with the software tools MAXWELL™2D and PRO-MECHANICA™. The designed actuator is evaluated with a linear current amplifier, a laser Doppler vibrometer for nanometer resolution, a dynamic signal analyzer for frequency responses of the proposed actuator, and a simple proportional-integral-derivative controller for its tracking performance.

  1. 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.

  2. 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

  3. 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

  4. Autonomous control system reconfiguration for spacecraft with non-redundant actuators

    NASA Technical Reports Server (NTRS)

    Grossman, Walter

    1995-01-01

    The Small Satellite Technology Initiative (SSTI) 'CLARK' spacecraft is required to be single-failure tolerant, i.e., no failure of any single component or subsystem shall result in complete mission loss. Fault tolerance is usually achieved by implementing redundant subsystems. Fault tolerant systems are therefore heavier and cost more to build and launch than non-redundent, non fault-tolerant spacecraft. The SSTI CLARK satellite Attitude Determination and Control System (ADACS) achieves single-fault tolerance without redundancy. The attitude determination system system uses a Kalman Filter which is inherently robust to loss of any single attitude sensor. The attitude control system uses three orthogonal reaction wheels for attitude control and three magnetic dipoles for momentum control. The nominal six-actuator control system functions by projecting the attitude correction torque onto the reaction wheels while a slower momentum management outer loop removes the excess momentum in the direction normal to the local B field. The actuators are not redundant so the nominal control law cannot be implemented in the event of a loss of a single actuator (dipole or reaction wheel). The spacecraft dynamical state (attitude, angular rate, and momentum) is controllable from any five-element subset of the six actuators. With loss of an actuator the instantaneous control authority may not span R(3) but the controllability gramian integral(limits between t,0) Phi(t, tau)B(tau )B(prime)(tau) Phi(prime)(t, tau)d tau retains full rank. Upon detection of an actuator failure the control torque is decomposed onto the remaining active axes. The attitude control torque is effected and the over-orbit momentum is controlled. The resulting control system performance approaches that of the nominal system.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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).

  13. A novel magnetic suspension cum linear actuator system for satellite cryo coolers

    SciTech Connect

    Sivadasan, K.K. . ISRO Inertial Systems Unit)

    1994-05-01

    Stirling cycle cryogenic coolers have been widely used for device cooling in satellites. Various types of magnetic bearings and linear actuators find application in such systems. The most widely used configurations have two-axis-radially-active suspension stations placed at either ends of a reciprocating shaft in the compression and expansion sections. Separate or integral liner motors are provided in each section for axial shaft movement. It may be noted that such configurations are rather complicated and less reliable because of the presence of numerous electro-mechanical components, sensors and electronic servo channels. In this paper, a simple and reliable scheme is suggested which axially stabilizes and linearly perturbs the piston so that the need for a separate motor for axial actuation can be totally dispensed with. The piston is radially supported by passive repulsive bearings. In the axial direction, a servo actuator balances'' the piston and also actuates it bi-directionally. Implemented of this bearing cum motor theme,'' reduces the number of electromechanical and electronic components required to operate the system and hence minimizes the chances of system failure. Apart from this, the system's power consumption is reduced and efficiency is improved as electrical heating losses caused by quiescent-operating currents are removed and electromagnetic losses on the moving parts are minimized. The necessary system parameters have been derived using finite element analysis techniques. Finally, the proposed design is validated by computer-aided system simulation.

  14. Prototyping a compact system for active vibration isolation using piezoelectric sensors and actuators

    NASA Astrophysics Data System (ADS)

    Shen, Hui; Wang, Chun; Li, Liufeng; Chen, Lisheng

    2013-05-01

    Being small in size and weight, piezoelectric transducers hold unique positions in vibration sensing and control. Here, we explore the possibility of building a compact vibration isolation system using piezoelectric sensors and actuators. The mechanical resonances of a piezoelectric actuator around a few kHz are suppressed by an order of magnitude via electrical damping, which improves the high-frequency response. Working with a strain gauge located on the piezoelectric actuator, an auxiliary control loop eliminates the drift associated with a large servo gain at dc. Following this approach, we design, optimize, and experimentally verify the loop responses using frequency domain analysis. The vibration isolation between 1 Hz and 200 Hz is achieved and the attenuation peaks at 60 near vibration frequency of 20 Hz. Restrictions and potentials for extending the isolation to lower vibration frequencies are discussed.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 30 CFR 250.1611 - Blowout preventer systems tests, actuations, inspections, and maintenance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 2 2012-07-01 2012-07-01 false Blowout preventer systems tests, actuations, inspections, and maintenance. 250.1611 Section 250.1611 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Sulphur Operations...

  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. Non-collinear valve actuator

    NASA Technical Reports Server (NTRS)

    Richard, James A. (Inventor)

    2012-01-01

    A non-collinear valve actuator includes a primary actuating system and a return spring system with each applying forces to a linkage system in order to regulate the flow of a quarter-turn valve. The primary actuating system and return spring system are positioned non-collinearly, which simply means the primary actuating system and return spring system are not in line with each other. By positioning the primary actuating system and return spring system in this manner, the primary actuating system can undergo a larger stroke while the return spring system experiences significantly less displacement. This allows the length of the return spring to be reduced due to the minimization of displacement thereby reducing the weight of the return spring system. By allowing the primary actuating system to undergo longer strokes, the weight of the primary actuating system may also be reduced. Accordingly, the weight of the non-collinear valve actuator is reduced.

  4. Effectiveness of a passive-active vibration isolation system with actuator constraints

    NASA Astrophysics Data System (ADS)

    Sun, Lingling; Sun, Wei; Song, Kongjie; Hansen, Colin H.

    2014-05-01

    In the prediction of active vibration isolation performance, control force requirements were ignored in previous work. This may limit the realization of theoretically predicted isolation performance if control force of large magnitude cannot be supplied by actuators. The behavior of a feed-forward active isolation system subjected to actuator output constraints is investigated. Distributed parameter models are developed to analyze the system response, and to produce a transfer matrix for the design of an integrated passive-active isolation system. Cost functions comprising a combination of the vibration transmission energy and the sum of the squared control forces are proposed. The example system considered is a rigid body connected to a simply supported plate via two passive-active isolation mounts. Vertical and transverse forces as well as a rotational moment are applied at the rigid body, and resonances excited in elastic mounts and the supporting plate are analyzed. The overall isolation performance is evaluated by numerical simulation. The simulation results are then compared with those obtained using unconstrained control strategies. In addition, the effects of waves in elastic mounts are analyzed. It is shown that the control strategies which rely on unconstrained actuator outputs may give substantial power transmission reductions over a wide frequency range, but also require large control force amplitudes to control excited vibration modes of the system. Expected power transmission reductions for modified control strategies that incorporate constrained actuator outputs are considerably less than typical reductions with unconstrained actuator outputs. In the frequency range in which rigid body modes are present, the control strategies can only achieve 5-10 dB power transmission reduction, when control forces are constrained to be the same order of the magnitude as the primary vertical force. The resonances of the elastic mounts result in a notable increase

  5. 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.

  6. 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.

  7. 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.

  8. Design and analysis of rotor systems with multiple trailing edge flaps and resonant actuators

    NASA Astrophysics Data System (ADS)

    Kim, Jun-Sik

    The purpose of this thesis is to develop piezoelectric resonant actuation systems and new active control methods utilizing the multiple trailing-edge flaps' configuration for rotorcraft vibration suppression and blade loads control. An aeroelastic model is developed for a composite rotor blade with multiple trailing-edge flaps. The rotor blade airloads are calculated using quasi-steady blade element aerodynamics with a free wake model for rotor inflow. A compressible unsteady aerodynamics model is employed to accurately predict the incremental trailing edge flap airloads. Both the finite wing effect and actuator saturation for trailing-edge flaps are also included in an aeroelastic analysis. For a composite articulated rotor, a new active blade loads control method is developed and tested numerically. The concept involves straightening the blade by introducing dual trailing edge flaps. The objective function, which includes vibratory hub loads, bending moment harmonics and active flap control inputs, is minimized by an integrated optimal control/optimization process. A numerical simulation is performed for the steady-state forward flight of an advance ratio of 0.35. It is demonstrated that through straightening the rotor blade, which mimics the behavior of a rigid blade, both the bending moments and vibratory hub loads can be significantly reduced by 32% and 57%, respectively. An active vibration control method is developed and analyzed for a hingeless rotor. The concept involves deflecting each individual trailing-edge flap using a compact resonant actuation system. Each resonant actuation system could yield high authority, while operating at a single frequency. Parametric studies are conducted to explore the finite wing effect of trailing-edge flaps and actuator saturation. A numerical simulation has been performed for the steady-state forward flight (mu = 0.15 ˜ 0.35). It is demonstrated that multiple trailing-edge flap configuration with the resonant actuation

  9. 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.

  10. On-orbit jitter control in momentum actuators using a three-flywheel system

    NASA Astrophysics Data System (ADS)

    Nagabhushan, Vivek; Fitz-Coy, Norman G.

    2014-02-01

    Vibrations on-board a spacecraft have degrading effects on the performance of certain payloads like astronomical telescopes, Earth observation systems, optical communication equipment, etc. The major source of these vibrations include momentum actuators used for attitude control, thrusters, solar array drives and other rotary mechanical equipment. The effect of these vibrations is spacecraft jitter which causes for example, smearing of images in a telescope. Spacecraft jitter due to rotor imbalance in momentum actuators is considered. Publications to date have researched isolation and suppression of vibration thus caused. This paper investigates the dynamics of jitter due to rotor imbalance and proposes a modification to the momentum actuators that provides a long term jitter management solution. The modification involves replacing a flywheel/rotor in the momentum actuator by a three-flywheel system. This method overcomes the need for prior precision balancing of individual flywheels and is capable of achieving a balanced system on orbit. It also provides limited redundancy against flywheel failure and may help accelerate testing and calibration. The dynamics of the three-flywheel system are developed and elaborate simulations are performed to verify the validity of the method. The performances of the proposed three-flywheel system and an equivalent single-flywheel system are compared. The effect of single/multiple flywheel failure in the three-flywheel system is investigated. An indicative design of the three-flywheel system and other implementation aspects are discussed to evidence its practicality. The potential increase in the mass, and power consumption of the three-flywheel system is discussed using a power and mass analysis based on the indicative design.

  11. Shape control of a morphing structure (rotor blade) using a shape memory alloy actuator system

    NASA Astrophysics Data System (ADS)

    Bushnell, Glenn S.; Arbogast, Darin; Ruggeri, Robert

    2008-03-01

    Development and test results of a rotor blade twist control system that utilizes a thermo-mechanical shape memory alloy (SMA) are presented. The actuation system controls the blade shape during flight operations allowing the blade to be configured for greater lift during takeoff and landing. SMA actuators provided an excellent solution because of their very high torque output to weight ratio and suitability to the dynamic environment of a rotor blade. Several challenges related to the behavior of the SMA material are overcome by innovative control system design. Thermoelectric modules (TEM's) are used to actively transfer heat between SMA tubes and other heat conductor and radiator components. Modeling and system identification techniques and a non-trivial solution to nonlinear and coupled thermal response equations are used to insure effective use of the TEM's and to improve control during SMA phase transition.

  12. 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

  13. Influence of Ordered Morphology on the Anisotropic Actuation in Uniaxially Oriented Electroactive Polymer Systems

    SciTech Connect

    Park, Jong Keun; Moore, Robert B.

    2009-06-12

    Ionic polymer-metal composites (IPMCs) are electroactive materials that undergo bending motions with the stimulus of a relatively weak electric field. To understand the fundamental role of the nanoscale morphology of the ionomer membrane matrix in affecting the actuation behavior of IPMC systems, we evaluated the actuation performance of IPMC materials subjected to uniaxial orientation. The perfluorinated ionomer nanostructure altered by uniaxial orientation mimicks the fibrillar structure of biological muscle tissue and yields a new anisotropic actuation response. It is evident that IPMCs cut from films oriented perpendicular to the draw direction yield tip-displacement values that are significantly greater than those of unoriented IPMCs. In contrast, IPMCs cut from films oriented parallel to the draw direction appear to resist bending and yield tip-displacement values that are much less than those of unoriented IPMCs. This anisotropic actuation behavior is attributed, in part, to the contribution of the fibrillar morphology to the bulk bending modulus. As an additional contribution, electrically stimulated water swelling perpendicular to the rodlike aggregate axis facilitates bending in the perpendicular direction.

  14. Characterization of electromechanical actuator implemented to phase-shift system applied to a Michelson interferometer

    NASA Astrophysics Data System (ADS)

    Barcelata-Pinzon, A.; Meneses Fabian, C.; Juarez-Salazar, R.; Durán-Sánchez, M.; Alvarez-Tamayo, R. I.; Robledo-Sánchez, C. I.; Muñoz-Mata, J. L.; Casco-Vázquez, J. F.

    2016-05-01

    Numerical results are presented to show the characterization of an electromechanical actuator capable to achieve equally spaced phase shifts and fraction linear wavelength displacements aided by an interface and a computational system. Measurements were performed by extracting the phase with consecutive interference patterns obtained in a Michelson arrangement setup. This paper is based in the use of inexpensive resources on stability adverse conditions to achieve similar results to those obtained with high-grade systems.

  15. 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.

  16. Robust reliable guaranteed cost control of positive interval systems with multiple time delays and actuator failure

    NASA Astrophysics Data System (ADS)

    Zhang, Ji-Shi; Wang, Yan-Wu; Xiao, Jiang-Wen; Chen, Yang

    2016-03-01

    This paper addresses the robust reliable guaranteed cost control problem of positive interval systems with multiple time delays and actuator failure for a given quadratic cost function. Through constructing a Lyapunov-Krasovskii functional, a sufficient condition for the existence of robust reliable guaranteed cost controllers is established such that the closed-loop system is positive and asymptotically stable, and the cost function is guaranteed to be no more than a certain upper bound. Based on the linear matrix inequality method, a criterion for the design of robust reliable guaranteed cost controllers is derived which can tolerate all admissible uncertainties as well as actuator failure. Moreover, a convex optimisation problem with linear matrix inequality constraints is formulated to design the optimal robust reliable guaranteed cost controller which minimises the upper bound of the closed-loop system cost. A numerical example is given to show the effectiveness of the proposed methods.

  17. 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.

  18. Bias Dependence of Gallium Nitride Micro-Electro-Mechanical Systems Actuation Using a Two-Dimensional Electron Gas

    NASA Astrophysics Data System (ADS)

    Amar, Achraf Ben; Faucher, Marc; Grimbert, Bertrand; Cordier, Yvon; Fran\\{c}ois, Marc; Tilmant, Pascal; Werquin, Matthieu; Zhang, Victor; Ducatteau, Damien; Gaquière, Christophe; Buchaillot, Lionel; Théron, Didier

    2012-06-01

    The piezoelectric actuation of a micro-electro-mechanical system (MEMS) resonator based on an AlGaN/GaN heterostructure is studied under various bias conditions. Using an actuator electrode that is also a transistor gate, we correlate the mechanical behaviour to the two-dimensional electron gas (2DEG) presence. The measured amplitude of the actuated resonator is maximum at moderate negative biases and drops near the pinch-off voltage in concordance with the 2DEG becoming depleted. Below the pinch-off voltage, residual actuation is still present, which is attributed to a more complex electric field pattern supported by quantitative modelling. The results confirm that epitaxial AlGaN barriers are fully adapted to the piezoelectric actuation of MEMS.

  19. 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.

  20. 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.

  1. 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. PMID:25792517

  2. H∞ fault-tolerant control for time-varied actuator fault of nonlinear system

    NASA Astrophysics Data System (ADS)

    Liu, Chunsheng; Jiang, Bin

    2014-12-01

    This paper studies H∞ fault-tolerant control for a class of uncertain nonlinear systems subject to time-varied actuator faults. A radial basis function neural network is utilised to approximate the unknown nonlinear functions; an updating rule is designed to estimate on-line time-varied fault of actuator; and the controller with the states feedback and faults estimation is applied to compensate for the effects of fault and minimise H∞ performance criteria in order to get a desired H∞ disturbance rejection constraint. Sufficient conditions are derived, which guarantees that the closed-loop system is robustly stable and satisfies the H∞ performance in both normal and fault cases. In order to reduce computing cost, a simplified algorithm of matrix Riccati inequality is given. A spacecraft model is presented to demonstrate the effectiveness of the proposed methods.

  3. Sensor and actuator conditioning for multiscale measurement systems on example of confocal microscopy

    NASA Astrophysics Data System (ADS)

    Lyda, W.; Zimmermann, J.; Burla, A.; Regin, J.; Osten, W.; Sawodny, O.; Westkämper, E.

    2009-06-01

    Multi-scale measurement systems utilise multiple sensors which differ in resolution and measurement field to pursue an active exploration strategy. The different sensor scales are linked by indicator algorithms for further measurement initiation. A major advantage of this strategy is a reduction of the conflict between resolution, time and field. This reduction is achieved by task specific conditioning of sensors, indicator algorithms and actuators using suitable uncertainty models. This contribution is focused on uncertainty models of sensors and actuators using the example of a prototype multi-scale measurement system. The influence of the sensor parameters, object characteristics and measurement conditions on the measurement reliability is investigated exemplary for the middle-scale sensor, a confocal microscope.

  4. 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.

  5. Null controllable region of delta operator systems subject to actuator saturation

    NASA Astrophysics Data System (ADS)

    Yang, Hongjiu; Yan, Ce; Xia, Yuanqing; Zhang, Jinhui

    2016-07-01

    In this paper, we give exact description of null controllable regions for delta operator systems subject to actuator saturation. The null controllable region is in terms of a set of extremal trajectories of anti-stable subsystems. For the delta operator system with real eigenvalues or complex eigenvalues, the description is simplified to an explicit formula which is used to characterise the boundary of a null controllable region. The relations of null controllable regions are shown separately for continuous-time systems, discrete-time systems and delta operator systems. Two numerical examples are given to illustrate the effectiveness of the proposed techniques on null controllable regions.

  6. Sensor/actuator failure detection and isolation for airbreathing propulsion systems

    NASA Technical Reports Server (NTRS)

    Leininger, G. G.; Behbehani, K.

    1980-01-01

    In this paper, the Generalized Likelihood Ratio (GLR) test is used to detect and isolate sensor and/or actuator failures when a digital computer simulation model of the physical system is available. The input to the GLR detector is an innovation sequence formed by subtracting the model outputs from the sensed outputs. Application of the GLR detector to the General Electric QCSEE turbofan engine demonstrates the utility of the proposed procedure.

  7. Design criteria for a self-actuated shutdown system to ensure limitation of core damage. [LMFBR

    SciTech Connect

    Deane, N.A.; Atcheson, D.B.

    1981-09-01

    Safety-based functional requirements and design criteria for a self-actuated shutdown system (SASS) are derived in accordance with LOA-2 success criteria and reliability goals. The design basis transients have been defined and evaluated for the CDS Phase II design, which is a 2550 MWt mixed oxide heterogeneous core reactor. A partial set of reactor responses for selected transients is provided as a function of SASS characteristics such as reactivity worth, trip points, and insertion times.

  8. 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.

  9. 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

  10. 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

  11. 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

  12. Quantum mechanical actuation of microelectromechanical systems by the Casimir force.

    PubMed

    Chan, H B; Aksyuk, V A; Kleiman, R N; Bishop, D J; Capasso, F

    2001-03-01

    The Casimir force is the attraction between uncharged metallic surfaces as a result of quantum mechanical vacuum fluctuations of the electromagnetic field. We demonstrate the Casimir effect in microelectromechanical systems using a micromachined torsional device. Attraction between a polysilicon plate and a spherical metallic surface results in a torque that rotates the plate about two thin torsional rods. The dependence of the rotation angle on the separation between the surfaces is in agreement with calculations of the Casimir force. Our results show that quantum electrodynamical effects play a significant role in such microelectromechanical systems when the separation between components is in the nanometer range. PMID:11239149

  13. 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.

  14. 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.

  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. 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

  18. Consensus control of multi-agent systems with missing data in actuators and Markovian communication failure

    NASA Astrophysics Data System (ADS)

    Hu, Yuebing; Lam, James; Liang, Jinling

    2013-10-01

    This article investigates the consensus problem of multi-agent systems (MASs) with imperfect communication both in channels and in actuators. The data transmission among agents may fail due to limited communication capacity, and the actuators may fail to receive information owing to noisy environment. We use a Markov chain approach to characterise the occurrence of the two types missing data in a unified framework. A sufficient consensus condition is first obtained in terms of linear matrix inequalities. Then, based on this condition, a novel controller design method is further developed such that the MAS with imperfect communication reaches mean-square consensus. It is shown that the consensus problem for MASs with switching topology can be regarded as a special case of the problem considered in this article, and the related theoretical results are presented as well. Numerical examples are provided to illustrate the effectiveness of the proposed approach.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Adaptive Neural Control of Nonaffine Systems With Unknown Control Coefficient and Nonsmooth Actuator Nonlinearities.

    PubMed

    Yang, Zaiyue; Yang, Qinmin; Sun, Youxian

    2015-08-01

    This brief considers the asymptotic tracking problem for a class of high-order nonaffine nonlinear dynamical systems with nonsmooth actuator nonlinearities. A novel transformation approach is proposed, which is able to systematically transfer the original nonaffine nonlinear system into an equivalent affine one. Then, to deal with the unknown dynamics and unknown control coefficient contained in the affine system, online approximator and Nussbaum gain techniques are utilized in the controller design. It is proven rigorously that asymptotic convergence of the tracking error and ultimate uniform boundedness of all the other signals can be guaranteed by the proposed control method. The control feasibility is further verified by numerical simulations. PMID:25265633

  4. A flat and cost effective actuator based on superabsorbent polymer driving a skin attachable drug delivery system

    NASA Astrophysics Data System (ADS)

    Vosseler, Michael; Clemenz, Markus; Zengerle, Roland

    2012-10-01

    We present a flat and cost effective volume displacement actuator based on superabsorbent polymer. It offers slow kinetics and is able to work against reasonable back-pressures, e.g. 0.50 ml in 235 min at 140 kPa. It is predestined for low-cost skin attachable drug delivery devices. The actuator consists of a plastic ring filled with superabsorbent polymer granulate. It is sealed with a thermoplastic elastomeric membrane on one side and a stiff filter membrane on the other side. After adding a defined amount (e.g. 2 or 10 ml) of swelling agent the actuator shows a fast initial volume displacement within a few minutes followed by a slow continuous increase of this volume within hours. Minimized initial volume displacement and maximized displaced volume after 4 h cannot be combined in one actuator. A minimized initial displacement can be as low as 0.10 ml± 0.03 ml. A maximized displaced volume after 4 h can be 1.71 ml± 0.18 ml, not considering the initial effect. The back-pressure dependency of one selected actuator design was studied. At a back-pressure of 100 kPa the displaced volume is reduced by 33%. We investigated various actuator designs with varying surface area, hardness of the elastomeric membrane and superabsorbent polymer. Finally, we demonstrate a skin attachable drug delivery system based on the employment of the superabsorbent polymer actuator.

  5. 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.

  6. An innovative ultra-capacitor driven shape memory alloy actuator with an embedded control system

    NASA Astrophysics Data System (ADS)

    Li, Peng; Song, Gangbing

    2014-08-01

    In this paper, an innovative ultra-capacitor driven shape memory alloy (SMA) actuator with an embedded control system is proposed targeting high power high-duty cycle SMA applications. The ultra-capacitor, which is capable of delivering massive amounts of instantaneous current in a compact dimension for high power applications, is chosen as the main component of the power supply. A specialized embedded system is designed from the ground up to control the ultra-capacitor driven SMA system. The control of the ultra-capacitor driven SMA is different from that of a regular constant voltage powered SMA system in that the energy and the voltage of the ultra-capacitor decrease as the system load increases. The embedded control system is also different from a computer-based control system in that it has limited computational power, and the control algorithm has to be designed to be simple while effective so that it can fit into the embedded system environment. The problem of a variable voltage power source induced by the use of the ultra-capacitor is solved by using a fuzzy PID (proportional integral and derivative) control. The method of using an ultra-capacitor to drive SMA actuators enabled SMA as a good candidate for high power high-duty cycle applications. The proposed embedded control system provides a good and ready-to-use solution for SMA high power applications.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. [Study on an actuation system for matrix control of the active catheter in a minimally-invasive intervention surgery].

    PubMed

    Fu, Yi-li; Ma, Hui-hui; Li, Xian-ling

    2006-11-01

    As it is impossible for an active catheter with a very small space to accommodate overmany lead wires in minimally-invasive surgery, a matrix network system is presented, in this paper, to control SMA actuators using minimum lead wires. Pulse current is adjusted by pulse width modulation (PWM) signals from the single-chip processor. In addition, multiple SMA actuators' cooperation helps the active catheter to succeed in guiding motion. PMID:17300007

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  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. 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. PMID:26838675

  5. 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.

  6. 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.

  7. Electro-Mechanical Actuators

    NASA Technical Reports Server (NTRS)

    2001-01-01

    The electro-mechanical actuator, a new electronics technology, is an electronic system that provides the force needed to move valves that control the flow of propellant to the engine. It is proving to be advantageous for the main propulsion system plarned for a second generation reusable launch vehicle. Hydraulic actuators have been used successfully in rocket propulsion systems. However, they can leak when high pressure is exerted on such a fluid-filled hydraulic system. Also, hydraulic systems require significant maintenance and support equipment. The electro-mechanical actuator is proving to be low maintenance and the system weighs less than a hydraulic system. The electronic controller is a separate unit powering the actuator. Each actuator has its own control box. If a problem is detected, it can be replaced by simply removing one defective unit. The hydraulic systems must sustain significant hydraulic pressures in a rocket engine regardless of demand. The electro-mechanical actuator utilizes power only when needed. A goal of the Second Generation Reusable Launch Vehicle Program is to substantially improve safety and reliability while reducing the high cost of space travel. The electro-mechanical actuator was developed by the Propulsion Projects Office of the Second Generation Reusable Launch Vehicle Program at the Marshall Space Flight Center.

  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. Angular-Momentum-Compensating Actuator

    NASA Technical Reports Server (NTRS)

    Wiktor, Peter J.

    1988-01-01

    Reactionless actuator developed for instrument-pointing platforms on flexible spacecraft; by eliminating reactions, actuator changes aiming angle of platform without inducing vibrations in spacecraft, eliminateing vibrations in point angle of instrument platform. Actuator used on Earth in such systems as helicopter platforms for television cameras in law enforcement and news telecasts.

  11. Design and development of a long-travel positioning actuator and tandem constant force actuator safety system for the Hobby Eberly Telescope wide-field upgrade

    NASA Astrophysics Data System (ADS)

    Mollison, Nicholas T.; Mock, Jason R.; Soukup, Ian M.; Beets, Timothy A.; Good, John M.; Beno, Joseph H.; Kriel, Herman J.; Hinze, Sarah E.; Wardell, Douglas R.; Heisler, James T.

    2010-07-01

    The Wide Field Upgrade presents a five-fold increase in mass for the Hobby-Eberly Telescope's* tracker system. The design of the Hobby-Eberly Telescope places the Prime Focus Instrument Package (PFIP) at a thirty-five degree angle from horizontal. The PFIP and its associated hardware have historically been positioned along this uphill axis (referred to as the telescope's Y-axis) by a single screw-type actuator. Several factors, including increased payload mass and design for minimal light obscuration, have led to the design of a new and novel configuration for the Y-axis screw-drive as part of the tracker system upgrade. Typical screw-drive designs in this load and travel class (approximately 50 kilonewtons traveling a distance of 4 meters) utilize a stationary screw with the payload translating with the moving nut component. The new configuration employs a stationary nut and translating roller screw affixed to the moving payload, resulting in a unique drive system design. Additionally, a second cable-actuated servo drive (adapted from a system currently in use on the Southern African Large Telescope) will operate in tandem with the screw-drive in order to significantly improve telescope safety through the presence of redundant load-bearing systems. Details of the mechanical design, analysis, and topology of each servo drive system are presented in this paper, along with discussion of the issues such a configuration presents in the areas of controls, operational and failure modes, and positioning accuracy. Findings and results from investigations of alternative telescope safety systems, including deformable crash barriers, are also included.

  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. Desiccant-based, heat-actuated cooling assessment for DHC (District Heating and Cooling) systems

    SciTech Connect

    Patch, K.D.; DiBella, F.A.; Becker, F.E.

    1990-07-01

    An assessment has been completed of the use of desiccant-based, heat-actuated cooling for District Heating and Cooling (DHC) systems, showing that such desiccant-based cooling (DBC) systems are generally applicable to District Heating (DH) systems. Since the DH system only has to supply hot water (or steam) to its customers, systems that were designed as conventional two-pipe DH systems can now be operated as DHC systems without major additional capital expense. Desiccant-based DHC systems can be operated with low-grade DH-supplied heat, at temperatures below 180{degree}F, without significant loss in operating capacity, relative to absorption chillers. During this assessment, a systems analysis was performed, an experimental investigation was conducted, developmental requirements for commercializing DBC systems were examined, and two case studies were conducted. As a result of the case studies, it was found that the operating cost of a DBC system was competitive with or lower than the cost of purchasing DHC-supplied chilled water. However, because of the limited production volume and the current high capital costs of desiccant systems, the payback period is relatively long. In this regard, through the substitution of low-cost components specifically engineered for low-temperature DHC systems, the capital costs should be significantly reduced and overall economics made attractive to future users. 17 figs.

  14. 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.

  15. 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.

  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. 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.

  18. 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.

  19. Development of damage monitoring system for aircraft structure using a PZT actuator/FBG sensor hybrid system

    NASA Astrophysics Data System (ADS)

    Ogisu, Toshimichi; Shimanuki, Masakazu; Kiyoshima, Satoshi; Okabe, Yoji; Takeda, Nobuo

    2004-07-01

    This paper presents a part of the research results on a damage monitoring system using PZT actuators/FBG sensors for advanced composite material structures of new-generation aircrafts. To achieve weight reduction of the aircraft structure, these advanced composite materials have gradually been employed for the primary structure. It is expected that when these materials are extensively employed, an efficient bonded structure such as a hat-shaped stringer will be utilized for the aircraft structure. However, these bonded structures have critical problems such as debonding and delamination at the interfaces of the laminate. Further, a single-step molding process of the structure elements is necessary in order to ensure low cost and thus affordability. However, this low-cost process results in an increase in the non-destructive inspection (NDI) cost. Therefore, an innovative damage monitoring system is required for structural health management. In the present study, the authors have developed a hybrid sensor system that can detect the elastic waves launched from the piezo transducer (PZT) actuator using a high-speed and high-accuracy fiber Bragg grating (FBG) sensor to resolve the issues mentioned above. In this study, the conceptual design of an aircraft that can employ this damage monitoring system was carried out. Subsequently, the application area was selected based on cases of certain kinds of damage. Further, the validity of the damage monitoring system for the verification of the structural integrity of the aircraft was discussed. Next, in order to verify the elastic wave detectability of the FBG sensor, it was confirmed that an elastic wave of 300 kHz is detectable at a distance of 5 cm between the PZT actuator and FBG sensor using an aluminum sheet and CFRP cross-ply laminate and also by considering the relationship between sensor length and sensitivity. Through the present research results, the possibility of applying the damage monitoring system to the

  20. X-Frame-actuator servo-flap acuation system for rotor control

    NASA Astrophysics Data System (ADS)

    Prechtl, Eric F.; Hall, Steven R.

    1998-07-01

    A design is presented of a 1/6 Mach scaled CH-47D rotor blade incorporating a X-Frame discrete actuator for control of a trailing edge servo-flap. The second generation design of the X-Frame actuator is described focusing on the design changes made from the actuator prototype. The function of the components that restrain the actuator to the rotor blade and connect it to the servo-flap are described. The major challenge in placing a discrete actuator into a rotor blade is in allowing the required functionality in the aggressive acceleration environment of the blade. In particular, a new centrifugal flexure is used to restrain the actuator in the spanwise direction and special fittings are incorporated into the blades to allow the required actuator degrees of freedom while reacting the out of plane vibrational accelerations of the blade. Concentric steel rods are used to transfer actuator motion to the servo-flap and to eliminate the compliant blade fairing from the actuation load path. A slotted flap design was used to reduce the required hinge moments. The aerodynamic implications of using such a flap design are described. Furthermore, retention of the flap and the pre-stress of the actuator were accomplished by a steel wire centered on the flap rotational axis. The design of this part and its influence on choosing an optimum flap length is discussed. The manufacture of the composite rotor blades is described. The diversion of composite unidirectional plies to allow access to the actuator bay within the blade spar is described.

  1. 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

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

    PubMed

    Huang, Jianzhang; Han, Qiang

    2016-04-15

    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. PMID:26934619

  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. Solid electrically tunable dual-focus lens using freeform surfaces and microelectro-mechanical-systems actuator.

    PubMed

    Zou, Yongchao; Zhang, Wei; Chau, Fook Siong; Zhou, Guangya

    2016-01-01

    In this Letter, a miniature solid tunable dual-focus (DF) lens, which is designed using freeform optical surfaces and driven by one microelectro-mechanical-systems rotary actuator, is reported. Such a lens consists of two optical elements, each having a flat surface and one freeform surface optimized by ray-tracing technology. By changing the relative rotation angle of the two lens elements, the lens configuration can form double foci with corresponding focal lengths varied simultaneously, resulting in a tunable DF effect. Results show that one of the focal lengths is tuned from about 30 to 20 mm, while the other one is varied from about 30 to 60 mm, with a maximum rotation angle of about 8.2 deg. PMID:26696143

  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. 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

  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. A Solar Energy Powered Autonomous Wireless Actuator Node for Irrigation Systems

    PubMed Central

    Lajara, Rafael; Alberola, Jorge; Pelegrí-Sebastiá, José

    2011-01-01

    The design of a fully autonomous and wireless actuator node (“wEcoValve mote”) based on the IEEE 802.15.4 standard is presented. The system allows remote control (open/close) of a 3-lead magnetic latch solenoid, commonly used in drip irrigation systems in applications such as agricultural areas, greenhouses, gardens, etc. The very low power consumption of the system in conjunction with the low power consumption of the valve, only when switching positions, allows the system to be solar powered, thus eliminating the need of wires and facilitating its deployment. By using supercapacitors recharged from a specifically designed solar power module, the need to replace batteries is also eliminated and the system is completely autonomous and maintenance free. The “wEcoValve mote” firmware is based on a synchronous protocol that allows a bidirectional communication with a latency optimized for real-time work, with a synchronization time between nodes of 4 s, thus achieving a power consumption average of 2.9 mW. PMID:22346580

  10. Structure-preserving model reduction for spatially interconnected systems with experimental validation on an actuated beam

    NASA Astrophysics Data System (ADS)

    Al-Taie, Fatimah; Werner, Herbert

    2016-06-01

    A technique for model reduction of exponentially stable spatially interconnected systems is presented, where the order of the reduced model is determined by the number of truncated small generalised singular values of the structured solutions to a pair of Lyapunov inequalities. For parameter-invariant spatially interconnected systems, the technique is based on solving a pair of Lyapunov inequalities in continuous-time and -space domain with a rank constraint. Using log-det and cone complementarity methods, an improved error bound can be obtained. The approach is extended to spatially parameter-varying systems, and a balanced truncation approach using parameter-dependent Gramians is proposed to reduce the conservatism caused by the use of constant Gramians. This is done by considering two important operators, which can be used to represent multidimensional systems (temporal- and spatial-linear parameter varying interconnected systems). The results are illustrated with their application to an experimentally identified spatially interconnected model of an actuated beam; the experimentally obtained response to an excitation signal is compared with the response predicted by a reduced model.