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Sample records for ac servo motors

  1. The application of Halbach cylinders to brushless ac servo motors

    SciTech Connect

    Atallah, K.; Howe, D.

    1998-07-01

    Halbach cylinders are applied to brushless ac servo motors. It is shown that a sinusoidal back-emf waveform and a low cogging torque can be achieved without recourse to conventional design features such as distributed windings and/or stator/rotor skew. A technique for imparting a multipole Halbach magnetization distribution on an isotropic permanent magnet cylinder is described, and it is shown that the torque capability of a Halbach ac servo motor can be up to 33% higher than conventional brushless permanent magnet ac motors.

  2. AC Servo Motor Based Position Sensorless Control System Making Use of Springs

    NASA Astrophysics Data System (ADS)

    Shimada, Akira; Kishiwada, Yu; Arimura, Michiyo

    This paper describes a position sensorless control technique on AC servo motor based position control systems. Shimada et al. had previously presented a paper on a DC servo motor based position sensorless control technique using mechanical springs. It was based on a point of view that mechanical springs form the key components for the observability. On the basis of the result obtained from the successful experiment, we assumed that the AC servo motor position sensorless control system would be identical. Using vector control, the controller needs the data of the magnetic pole position on the rotor of the AC servo motor. It is not perfect sensorless control, since it use a rotary encoder. However, we introduce it and demonstrate the expreimental results as an initial step in the new control technology.

  3. Continuous Path Tracking Control by Considering Voltage Saturation and Current Saturation for AC Servo Motor

    NASA Astrophysics Data System (ADS)

    Sazawa, Masaki; Ohishi, Kiyoshi; Katsura, Seiichiro

    Continuous path tracking control is an important technology for the position control system such as factory automation field. Particulaly, large torque is required for continuous path tracking control at its start position and its goal position. Each AC servo motor of continuous path tracking control have limitation of current and voltage. Therefore, in controlling a multi-degree-of-freedom continuous path tracking control system, even if only the motor torque of one axis has the current limitation, the actual position response is not often equal to the desired trajectory reference. In order to overcome these problems, this paper proposes a new continuous path tracking control algorithm by considering both the saturation of voltage and current. The proposed method assures the coordinated motion by considering the saturation of voltage and current. The effectiveness of the proposed method is confirmed by the experimental results in this paper.

  4. A Servo System of AC Motor Based on Voltage Modulation Fitting for FPGA and Consideration of Voltage Saturation

    NASA Astrophysics Data System (ADS)

    Takahashi, Kenji; Kanmachi, Tosiyuki; Ohishi, Kiyoshi

    This paper proposes a space voltage vector modulation (SVM) method for a speed servo system to obtain a quick current response. The proposed SVM method shortens the control lag time of the conventional SVM inverter. In addition, this proposed method is easily implemented of the hardware using a FPGA (Field Programmable Gate Array) because the proposed SVM equations is transformed into the expressions that hardly needs multiplication. By using the proposed SVM method, the servo system realizes a quick and stable current control with wide bandwidth. Moreover, by using PI controllers considering the voltage saturation and the torque limiter to the speed servo system, the servo system carries out a stable speed control on voltage saturation. Both the proposed SVM method and the PI controllers considering the voltage saturation are applied to a speed servo system of a vector controlled induction motor. The effectiveness of both the proposed SVM method and the PI controllers considering voltage saturation is verified by the experimental results.

  5. Fuzzy control of small servo motors

    NASA Technical Reports Server (NTRS)

    Maor, Ron; Jani, Yashvant

    1993-01-01

    To explore the benefits of fuzzy logic and understand the differences between the classical control methods and fuzzy control methods, the Togai InfraLogic applications engineering staff developed and implemented a motor control system for small servo motors. The motor assembly for testing the fuzzy and conventional controllers consist of servo motor RA13M and an encoder with a range of 4096 counts. An interface card was designed and fabricated to interface the motor assembly and encoder to an IBM PC. The fuzzy logic based motor controller was developed using the TILShell and Fuzzy C Development System on an IBM PC. A Proportional-Derivative (PD) type conventional controller was also developed and implemented in the IBM PC to compare the performance with the fuzzy controller. Test cases were defined to include step inputs of 90 and 180 degrees rotation, sine and square wave profiles in 5 to 20 hertz frequency range, as well as ramp inputs. In this paper we describe our approach to develop a fuzzy as well as PH controller, provide details of hardware set-up and test cases, and discuss the performance results. In comparison, the fuzzy logic based controller handles the non-linearities of the motor assembly very well and provides excellent control over a broad range of parameters. Fuzzy technology, as indicated by our results, possesses inherent adaptive features.

  6. A novel approach implementing AC position servo system

    NASA Astrophysics Data System (ADS)

    Li, Bo; Sun, Li; Kang, Erliang; Esmaeli, Abdolreza

    2005-12-01

    This paper proposed a method which was based on DSP and FPGA and applied in the fully digital and high-performance permanent magnet synchronous motor (PMSM) AC servo system. In the system, the position loop control combined PI control and feedforward control was implemented by DSP unit, while the speed loop and current loop control were implemented by FPGA unit. Since FPGA provided a kind of hardware design scheme for the control system, it had the features of a special control IC. The functions of vector control algorithm, velocity and current sampling, space vector pulse width modulation and PI algorithm were included in the special control IC. In the meanwhile, it also provided host communication interfaces that could realize the real-time modification of the control parameters in the IC. Finally, the experimental results indicate that this system has high-speed response and well static state control performance.

  7. Fully digital controlled A.C. servo engraving machine based on DEC4DA

    NASA Astrophysics Data System (ADS)

    Shu, Zhibing; Chen, Xianfeng; Zhang, Hairong; Huang, Yiqun; Yan, Caizhong

    2005-12-01

    A novel engraving machine (NUT-1A) is presented, in which fully digital controlled AC system based on DEC4DA was used to improve the machining precision and sensitivity. This engraving machine was constructed around AC servo motor with encoder, controlled by a servo motor control card - DEC4DA. As the upper unit of AC servo motor, DEC4DA was a numerical control generator, which received pulses form CPU by ISA bus, and these pulses were amplified and converted to drive AC servo actuator. This novel engraving machine can achieve a higher positioning accuracy of +/-0.01mm and positioning repetition of +/-0.005mm, and its resolution is 0.001mm/0.0001mm. Moreover, because of multi-closed loops were used in the system, the steady and transient performances are more excellent. This system ensures a much quicker current regulation in closed-loop operation, of acceleration and braking in both directions, as well as stable speed characteristics. Amplifier boards are protected against excessive current, excessive temperature and short circuiting of the motor supply cables.

  8. 12. Turbine Pit Servo Motors of Unit 1, view to ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. Turbine Pit Servo Motors of Unit 1, view to the southeast. The servo motors are set into wall recesses and operated by the governors. Note the wicket gate linkages visible in the lower center of the photograph, between the deck plates and the operating ring. Also note the wicket gate linkage grease lines along the wall just below the lights. - Washington Water Power Clark Fork River Noxon Rapids Hydroelectric Development, Powerhouse, South bank of Clark Fork River at Noxon Rapids, Noxon, Sanders County, MT

  9. ac bidirectional motor controller

    NASA Technical Reports Server (NTRS)

    Schreiner, K.

    1988-01-01

    Test data are presented and the design of a high-efficiency motor/generator controller at NASA-Lewis for use with the Space Station power system testbed is described. The bidirectional motor driver is a 20 kHz to variable frequency three-phase ac converter that operates from the high-frequency ac bus being designed for the Space Station. A zero-voltage-switching pulse-density-modulation technique is used in the converter to shape the low-frequency output waveform.

  10. Modeling of R/C Servo Motor and Application to Underactuated Mechanical Systems

    NASA Astrophysics Data System (ADS)

    Ishikawa, Masato; Kitayoshi, Ryohei; Wada, Takashi; Maruta, Ichiro; Sugie, Toshiharu

    An R/C servo motor is a compact package of a DC geard-motor associated with a position servo controller. They are widely used in small-sized robotics and mechatronics by virtue of their compactness, easiness-to-use and high/weight ratio. However, it is crucial to clarify their internal model (including the embedded position servo) in order to improve control performance of mechatronic systems using R/C servo motors, such as biped robots or underactuted sysyems. In this paper, we propose a simple and realistic internal model of the R/C servo motors including the embedded servo controller, and estimate their physical parameters using continuous-time system identification method. We also provide a model of reference-to-torque transfer function so that we can estimate the internal torque acting on the load.

  11. Myoelectric hand prosthesis force control through servo motor current feedback.

    PubMed

    Sono, Tálita Saemi Payossim; Menegaldo, Luciano Luporini

    2009-10-01

    This paper presents the prehension force closed-loop control design of a mechanical finger commanded by electromyographic signal (EMG) from a patient's arm. The control scheme was implemented and tested in a mechanical finger prototype with three degrees of freedom and one actuator, driven by arm muscles EMG of normal volunteers. Real-time indirect estimation of prehension force was assessed by measuring the DC servo motor actuator current. A model of the plant comprising finger, motor, and grasped object was proposed. Model parameters were identified experimentally and a classical feedback phase-lead compensator was designed. The controlled mechanical finger was able to provide a more accurate prehension force modulation of a compliant object when compared to open-loop control. PMID:19681841

  12. Permanent magnet synchronous motor servo system control based on μC/OS

    NASA Astrophysics Data System (ADS)

    Shi, Chongyang; Chen, Kele; Chen, Xinglong

    2015-10-01

    When Opto-Electronic Tracking system operates in complex environments, every subsystem must operate efficiently and stably. As a important part of Opto-Electronic Tracking system, the performance of PMSM(Permanent Magnet Synchronous Motor) servo system affects the Opto-Electronic Tracking system's accuracy and speed greatly[1][2]. This paper applied embedded real-time operating system μC/OS to the control of PMSM servo system, implemented SVPWM(Space Vector Pulse Width Modulation) algorithm in PMSM servo system, optimized the stability of PMSM servo system. Pointing on the characteristics of the Opto-Electronic Tracking system, this paper expanded μC/OS with software redundancy processes, remote debugging and upgrading. As a result, the Opto- Electronic Tracking system performs efficiently and stably.

  13. Three phase AC motor controller

    DOEpatents

    Vuckovich, Michael; Wright, Maynard K.; Burkett, John P.

    1984-03-20

    A motor controller for a three phase AC motor (10) which is adapted to operate bidirectionally from signals received either from a computer (30) or a manual control (32). The controller is comprised of digital logic circuit means which implement a forward and reverse command signal channel (27, 29) for the application of power through the forward and reverse power switching relays (16, 18, 20, 22). The digital logic elements are cross coupled to prevent activation of both channels simultaneously and each includes a plugging circuit (65, 67) for stopping the motor upon the removal of control signal applied to one of the two channels (27, 29) for a direction of rotation desired. Each plugging circuit (65, 67) includes a one-shot pulse signal generator (88, 102) which outputs a single pulse signal of predetermined pulsewidth which is adapted to inhibit further operation of the application of power in the channel which is being activated and to apply a reversal command signal to the other channel which provides a reversed phase application of power to the motor for a period defined by the pulse-width output of the one-shot signal generator to plug the motor (10) which will then be inoperative until another rotational command signal is applied to either of the two channels.

  14. Influence of magnetic reluctances of magnetic elements on servo valve torque motors

    NASA Astrophysics Data System (ADS)

    Liu, Changhai; Jiang, Hongzhou

    2016-01-01

    The current research of electro-hydraulic servo valves mainly focuses on the vibration, pressure oscillating and source of noise. Unfortunately, literatures relating to the study of the influence of the magnetic reluctances of the magnetic elements are rarely available. This paper aims to analyze the influence of the magnetic reluctances of the magnetic elements on torque motor. Considering these magnetic reluctances ignored in previous literatures, a new mathematical model of servo valve torque motor is developed and proposed based on the fundamental laws of electromagnetism. By using this new mathematical model and the previous models, electromagnetic torque constant and magnetic spring stiffness are evaluated for a given set of torque motor parameters. A computer simulation by using AMESim software is also performed for the same set of torque motor parameters to verify the proposed model. The theoretical results of electromagnetic torque constant and magnetic spring stiffness evaluated by the proposed model render closer agreement with the simulation results than those evaluated by the previous models. In addition, an experimental measurement of the magnetic flux densities in the air-gaps is carried out by using SFL218 servo valve torque motor. Compared with the theoretical results of the magnetic flux densities in the air-gaps evaluated by the previous models, the theoretical results evaluated by the proposed model also show better agreement with the experimental data. The proposed model shows the influence of the magnetic reluctances of the magnetic elements on the servo valve torque motor, and offers modified and analytical expressions to electromagnetic torque constant and magnetic spring stiffness. These modified and analytical expressions could provide guidance more accurately for a linear control design approach and sensitivity analysis on electro-hydraulic servo valves than the previous expressions.

  15. Development of Novel Magnetic Encoder and Vector Control Method for Servo Control of High-Speed Motor

    NASA Astrophysics Data System (ADS)

    Hao, Shuanghui; Liu, Jie; Mizugaki, Yoshio

    This paper presents a novel unipolar magnetic encoder and a new Vector control method of AC servo which can enable the feedback of the rotor position with high accuracy in high speed occasion. The signal generator of encoder consists of three pairs of semiconductor hall elements and a rotor of alnico magnet with one pair of poles. This encoder is featured with the operation module and the communication module to transmit an angular data in the form of asynchronous serial transfer protocol. Besides, a delay compensation algorithm is proposed to ensure the accurate estimation of instant angular position and the estimation error is also analyzed. At last, an experimental apparatus was built for a 600W, 4 pairs of pole, at rated speed 20,000min-1, permanent-magnet synchronous motor drive and the proposed vector control scheme has been implemented. The experiment results supported the validity of the proposed magnetic encoder and vector control method for high-speed AC servo control within 0.05 % error of revolving speed.

  16. Damping properties for vibration suppression in electrohydraulic servo-valve torque motor using magnetic fluid

    NASA Astrophysics Data System (ADS)

    Peng, Jinghui; Li, Songjing; Han, Hasiaoqier

    2014-04-01

    Aiming to suppress high frequency vibrations of a torque motor in electrohydraulic servo-valves, damping properties of an ester-based Fe3O4 magnetic fluid operating in the squeeze mode are studied in this Letter. The expression of damping forces due to the magnetic fluid on the torque motor is derived and simplified based on the measured magneto-viscosity property. Dynamic characteristics of the torque motor with and without the magnetic fluid are simulated and tested. Damping properties of magnetic fluid for the vibration suppression of a torque motor are verified by the good agreement between the predicted and tested results.

  17. An adaptive fuzzy controller for permanent-magnet AC servo drives

    SciTech Connect

    Le-Huy, H.

    1995-12-31

    This paper presents a theoretical study on a model-reference adaptive fuzzy logic controller for vector-controlled permanent-magnet ac servo drives. In the proposed system, fuzzy logic is used to implement the direct controller as well as the adaptation mechanism. The operation of the direct fuzzy controller and the fuzzy logic based adaptation mechanism is studied. The control performance of the adaptive fuzzy controller is evaluated by simulation for various operating conditions. The results are compared with that provided by a non-adaptive fuzzy controller. The implementation of proposed adaptive fuzzy controller is discussed.

  18. A novel method for simulation of brushless DC motor servo-control system based on MATLAB

    NASA Astrophysics Data System (ADS)

    Tao, Keyan; Yan, Yingmin

    2006-11-01

    This paper provides a research about the simulation of brush-less DC motor (BLDCM) servo control system. Based on the mathematical model of Brush-less DC motor (BLDCM), built the system simulation model with the MATLAB software. When the system model is made, the isolated functional blocks, such as BLDCM block, the rotor's position detection block, change-phase logic block etc. have been modeled. By the organic combination of these blocks, the model of BLDCM can be established easily. The reasonability and validity have been testified by the simulation results and this novel method offers a new thought way for designing and debugging actual motors.

  19. Data-Driven Based Asynchronous Motor Control for Printing Servo Systems

    NASA Astrophysics Data System (ADS)

    Bian, Min; Guo, Qingyun

    Modern digital printing equipment aims to the environmental-friendly industry with high dynamic performances and control precision and low vibration and abrasion. High performance motion control system of printing servo systems was required. Control system of asynchronous motor based on data acquisition was proposed. Iterative learning control (ILC) algorithm was studied. PID control was widely used in the motion control. However, it was sensitive to the disturbances and model parameters variation. The ILC applied the history error data and present control signals to approximate the control signal directly in order to fully track the expect trajectory without the system models and structures. The motor control algorithm based on the ILC and PID was constructed and simulation results were given. The results show that data-driven control method is effective dealing with bounded disturbances for the motion control of printing servo systems.

  20. Nonlinear servo control of an induction motor with saturation

    SciTech Connect

    Bodson, M.; Chiasson, J.; Novotnak, R.

    1994-12-31

    This work is an extension of the authors` previous work on high-performance induction motor control in which the magnetic model of the motor was assumed to be linear. Saturation of the iron in the main path of the induction machine is taken into account. The saturation is modeled in the dq coordinate frame and the model is then used to design an input-output linearization controller to provide independent (decoupled) control of the speed and flux. With this controller, the flux reference becomes an extra degree of freedom for the designer to help achieve performance objectives. Taking into account saturation, the flux reference is chosen to achieve the optimal torque (maximum for acceleration & minimum for deceleration) at any given speed. The input-output controller is used to provide tracking of a given position & speed trajectory while simultaneously tracking the optimal flux reference. Experimental results are given to validate the approach.

  1. Identification and robust control of an experimental servo motor.

    PubMed

    Adam, E J; Guestrin, E D

    2002-04-01

    In this work, the design of a robust controller for an experimental laboratory-scale position control system based on a dc motor drive as well as the corresponding identification and robust stability analysis are presented. In order to carry out the robust design procedure, first, a classic closed-loop identification technique is applied and then, the parametrization by internal model control is used. The model uncertainty is evaluated under both parametric and global representation. For the latter case, an interesting discussion about the conservativeness of this description is presented by means of a comparison between the uncertainty disk and the critical perturbation radius approaches. Finally, conclusions about the performance of the experimental system with the robust controller are discussed using comparative graphics of the controlled variable and the Nyquist stability margin as a robustness measurement. PMID:12071255

  2. Power control for ac motor

    NASA Technical Reports Server (NTRS)

    Dabney, R. W. (Inventor)

    1984-01-01

    A motor controller employing a triac through which power is supplied to a motor is described. The open circuit voltage appearing across the triac controls the operation of a timing circuit. This timing circuit triggers on the triac at a time following turn off which varies inversely as a function of the amplitude of the open circuit voltage of the triac.

  3. Power factor control system for ac induction motors

    NASA Technical Reports Server (NTRS)

    Nola, F. J. (Inventor)

    1981-01-01

    A power control circuit for an induction motor is disclosed in which a servo loop is used to control power input by controlling the power factor of motor operation. The power factor is measured by summing the voltage and current derived square wave signals.

  4. Operation Method for AC Motor Control during Power Interruption in Direct AC/AC Converter System

    NASA Astrophysics Data System (ADS)

    Shizu, Keiichiro; Azuma, Satoshi

    Direct AC/AC converters have been studied due to their potential use in power converters with no DC-link capacitor, which can contribute to the miniaturization of power converters. However, the absence of a DC-link capacitor makes it difficult to control the AC motor during power interruption. First, this paper proposes a system that realizes AC motor control during power interruption by utilizing a clamp capacitor. In general, direct AC/AC converters have a clamp circuit consisting of a rectifier diode(s) and a clamp capacitor in order to avoid over-voltages. In the proposed system, there is an additional semiconductor switch reverse-parallel to the rectifier diode(s), and the clamp capacitor voltage can be utilized for AC motor control by turning on the additional switch. Second, this paper discusses an operation method for AC motor control and clamp capacitor voltage control during power interruption. In the proposed method “DC-link voltage control”, the kinetic energy in the AC motor is transformed into electrical energy and stored in the clamp capacitor; the clamp capacitor is therefore charged and the capacitor voltage is controlled to remain constant at an instruction value. Third, this paper discusses a switching operation during power interruption. A dead-time is introduced between the operation of turning off all switches on the rectifier side and the operation of turning on the additional switch, which prevents the occurrence of a short circuit between the interrupted power source and the clamp capacitor. Finally, experimental results are presented. During power interruptions, an output current was continuously obtained and the clamp capacitor voltage was maintained to be equal to the instruction value of the capacitor voltage. These results indicate that both AC motor control and capacitor voltage control were successfully achieved by using the proposed system.

  5. System and method for determining stator winding resistance in an AC motor using motor drives

    DOEpatents

    Lu, Bin; Habetler, Thomas G; Zhang, Pinjia

    2013-02-26

    A system and method for determining the stator winding resistance of AC motors is provided. The system includes an AC motor drive having an input connectable to an AC source and an output connectable to an input terminal of an AC motor, a pulse width modulation (PWM) converter having switches therein to control current flow and terminal voltages in the AC motor, and a control system connected to the PWM converter. The control system generates a command signal to cause the PWM converter to control an output of the AC motor drive corresponding to an input to the AC motor, selectively generates a modified command signal to cause the PWM converter to inject a DC signal into the output of the AC motor drive, and determines a stator winding resistance of the AC motor based on the DC signal of at least one of the voltage and current.

  6. Fuzzy efficiency optimization of AC induction motors

    NASA Technical Reports Server (NTRS)

    Jani, Yashvant; Sousa, Gilberto; Turner, Wayne; Spiegel, Ron; Chappell, Jeff

    1993-01-01

    This paper describes the early states of work to implement a fuzzy logic controller to optimize the efficiency of AC induction motor/adjustable speed drive (ASD) systems running at less than optimal speed and torque conditions. In this paper, the process by which the membership functions of the controller were tuned is discussed and a controller which operates on frequency as well as voltage is proposed. The membership functions for this dual-variable controller are sketched. Additional topics include an approach for fuzzy logic to motor current control which can be used with vector-controlled drives. Incorporation of a fuzzy controller as an application-specific integrated circuit (ASIC) microchip is planned.

  7. Power factor control system for AC induction motors

    NASA Technical Reports Server (NTRS)

    Nola, F. J. (Inventor)

    1977-01-01

    A power factor control system for use with ac induction motors was designed which samples lines voltage and current through the motor and decreases power input to the motor proportional to the detected phase displacement between current and voltage. This system provides, less power to the motor, as it is less loaded.

  8. Dynamic Analysis and Vibration Control of a Flexible SLIDER-CRANK Mechanism Using PM Synchronous Servo Motor Drive

    NASA Astrophysics Data System (ADS)

    Fung, R.-F.; Chen, K.-W.

    1998-07-01

    Dynamic analysis and vibration control of a flexible slider-crank mechanism driven by a permanent magnet (PM) synchronous servo motor are studied in this paper. Geometric constraint at the end of a flexible connecting rod is derived and introduced into Hamilton's principle to formulate the governing equations of the connecting rod which is modelled by Timoshenko beam theory. The coupling equations describe the rigid-body motion, flexible vibrations and motor system. In order to control crank speed and reduce flexible vibrations simultaneously, speed and tracking controllers are designed through a reaching law variable structure control (VSC) method. By choosing proper parameters in control law, dynamic responses of the flexible system in reaching mode can be controlled. Numerical results show that the proposed controllers not only eliminate the dynamic deflections of the flexible connecting rod, but also keep good tracking performances. Moreover, the robustness against external disturbances can also be improved by employing the proposed control scheme.

  9. IMPROVING AC MOTOR EFFICIENCY WITH FUZZY LOGIC ENERGY OPTIMIZER

    EPA Science Inventory

    The paper discusses EPA's research program to develop fuzzy-logic-based energy optimizers for alternating-current (AC) induction motors driven by Adjustable Speed Drives (ASDs). he technical goals of the program are to increase the efficiency of ASD/motor combinations (especially...

  10. Sensorless operation of surface mount permanent magnet AC (PMAC) motors

    SciTech Connect

    Toliyat, H.A.; Rahman, K.M.; Shet, D.S.

    1999-12-01

    A sensorless field oriented control scheme for surface mount permanent magnet ac (PMAC) motor with split phase stator windings is presented. This motor is obtained by splitting the phase windings of a conventional three phase motor. The six-phase motor, however is run as a three-phase motor by connecting the split phase stator windings in series, while the taps are made available for voltage measurements. By measuring the terminal voltages and the line currents, absolute position of the permanent magnet ac motor driven by a current regulated PWM inverter with a hysteresis controller is estimated. The estimated position information is independent of the stator resistance, thus this scheme is even applicable at low speeds. Results are presented to show the effectiveness of the new controller, and it is also shown that the position error is negligible.

  11. FUZZY LOGIC CONTROL OF AC INDUCTION MOTORS

    EPA Science Inventory

    The paper discusses the fuzzy logic control (FLC) of electric motors, being investigated under the sponsorship of the U.S. EPA to reduce energy consumption when motors are operated at less than rated speeds and loads. lectric motors use 60% of the electrical energy generated in t...

  12. Save power in AC induction motors

    NASA Technical Reports Server (NTRS)

    Nola, F. J.

    1977-01-01

    Relatively simple and inexpensive circuitry improves power factor and reduces power dissipation in induction motors operating below full load. Electronic control loop conserves energy by reducing voltage applied to lightly loaded motor. Circuit forces motor to run at constant predetermined optimum power factor, regardless of load or line voltage variations. Solid-state switch varies voltage.

  13. Sequential control by speed drive for ac motor

    NASA Astrophysics Data System (ADS)

    Barsoum, Nader

    2012-11-01

    The speed drive for ac motor is widely used in the industrial field to allow direct control for the speed and torque without any feedback from the motor shaft. By using the ABB ACS800 speed drive unit, the speed and torque can be controlled using sequential control method. Sequential control is one of the application control method provided in the ABB ACS800 Drive, where a set of events or action performed in a particular order one after the other to control the speed and torque of the ac motor. It was claimed that sequential control method is using the preset seven constant speeds being provided in ABB ACS800 drive to control the speed and torque in a continuous and sequential manner. The characteristics and features of controlling the speed and torque using sequential control method can be investigated by observing the graphs and curves plotted which are obtained from the practical result. Sequential control can run either in the Direct Torque Control (DTC) or Scalar motor control mode. By using sequential control method, the ABB ACS800 drive can be programmed to run the motor automatically according to the time setting of the seven preset constant speeds. Besides, the intention of this project is to generate a new form of the experimental set up.

  14. Motor power control circuit for ac induction motors

    NASA Technical Reports Server (NTRS)

    Nola, F. J. (Inventor)

    1983-01-01

    A motor power control of the type which functions by controlling the power factor wherein one of the parameters of power factor current on time is determined by the on time of a triac through which current is supplied to the motor. By means of a positive feedback circuit, a wider range of control is effected.

  15. MACE telescope : Servo design aspects

    NASA Astrophysics Data System (ADS)

    Mayya, Y. S.; Srivastava, G. P.; Koul, R.

    2002-03-01

    The design parameters of the servo system for the MACE imaging Cerenkov telescope, based on functional, performance, operational and safety requirements of the system are briefly discussed. The servo system is designed around electronically commutated motors using fully digital controllers, pc-compatible hardware and software and ethernet connectivity for remote monitoring and control.

  16. Variable-frequency inverter controls torque, speed, and braking in ac induction motors

    NASA Technical Reports Server (NTRS)

    Nola, F. J.

    1974-01-01

    Dc to ac inverter provides optimum frequency and voltage to ac induction motor, in response to different motor-load and speed requirements. Inverter varies slip frequency of motor in proportion to required torque. Inverter protects motor from high current surges, controls negative slip to apply braking, and returns energy stored in momentum of load to dc power source.

  17. Designing LC filters for AC-motor drives

    SciTech Connect

    Gath, P.A.; Lucas, M.

    1995-12-31

    This paper presents practical design guidelines for designing LC filters for AC-motor drive applications. A DC choke and an electrolytic capacitor bank on the DC bus filter the voltage and the current ripples and improve the input power factor. Capacitor and choke values are derived to optimize overall filter performance. Costs associated with the respective component values can then be obtained to analyze cost trade-offs between selected values. Helpful hints are also given.

  18. A fully digital control strategy for synchronous reluctance motor servo drives

    SciTech Connect

    Xiang, Y.Q.; Nasar, S.A.

    1995-12-31

    For existing electric drives, the controller implementation is either totally analog or hybrid analog/digital, and the control algorithm broadly falls into two categories: Average Torque Control (ATC) and Instantaneous Torque Control (InsTC). In this paper, a fully digital implementation oriented control strategy--Incremental Torque Control (IncTC)--is proposed and verified with digital simulation. A TMS320C30 DSP based implementation of the proposed IncTC is developed and tested. Experimental results given in the paper indicate that the proposed IncTC is valid and holds a great promise for reluctance motor digital control.

  19. AC motor controller with 180 degree conductive switches

    NASA Technical Reports Server (NTRS)

    Oximberg, Carol A. (Inventor)

    1995-01-01

    An ac motor controller is operated by a modified time-switching scheme where the switches of the inverter are on for electrical-phase-and-rotation intervals of 180.degree. as opposed to the conventional 120.degree.. The motor is provided with three-phase drive windings, a power inverter for power supplied from a dc power source consisting of six switches, and a motor controller which controls the current controlled switches in voltage-fed mode. During full power, each switch is gated continuously for three successive intervals of 60.degree. and modulated for only one of said intervals. Thus, during each 60.degree. interval, the two switches with like signs are on continuously and the switch with the opposite sign is modulated.

  20. A Motor Speed Servo System Based on the Dual Loop PLL

    NASA Astrophysics Data System (ADS)

    Machida, Hidekazu; Kambara, Michinobu; Tanaka, Kouta; Kobayashi, Fuminori

    PLL-MSC (Phase Locked Loop Motor Speed Control) systems can completely reject speed error and steady-state phase error for constant-speed input signals. However, it is not usually applied to systems with inputs including acceleration, because they have poor tracking speed and strange pull-in behavior. In the field of radio communication, “dual-loop PLL” is very effective for such signals. It can not only enable high-speed tracking, but also cancel phase error. In the digital implementation of the PLL-MSC, it can achive easily by inserting loop filters into both feed back paths, and employed a special adder in PWM to implement loop addition for the two phase detector outputs. The scheme was implemented by programming an FPGA, and satisfiable results were obtained.

  1. Offline detection of broken rotor bars in AC induction motors

    NASA Astrophysics Data System (ADS)

    Powers, Craig Stephen

    ABSTRACT. OFFLINE DETECTION OF BROKEN ROTOR BARS IN AC INDUCTION MOTORS. The detection of the broken rotor bar defect in medium- and large-sized AC induction machines is currently one of the most difficult tasks for the motor condition and monitoring industry. If a broken rotor bar defect goes undetected, it can cause a catastrophic failure of an expensive machine. If a broken rotor bar defect is falsely determined, it wastes time and money to physically tear down and inspect the machine only to find an incorrect diagnosis. Previous work in 2009 at Baker/SKF-USA in collaboration with the Korea University has developed a prototype instrument that has been highly successful in correctly detecting the broken rotor bar defect in ACIMs where other methods have failed. Dr. Sang Bin and his students at the Korea University have been using this prototype instrument to help the industry save money in the successful detection of the BRB defect. A review of the current state of motor conditioning and monitoring technology for detecting the broken rotor bar defect in ACIMs shows improved detection of this fault is still relevant. An analysis of previous work in the creation of this prototype instrument leads into the refactoring of the software and hardware into something more deployable, cost effective and commercially viable.

  2. Fast recovery, high voltage silicon diodes for AC motor controllers

    NASA Technical Reports Server (NTRS)

    Balodis, V.; Berman, A. H.; Gaugh, C.

    1982-01-01

    The fabrication and characterization of a high voltage, high current, fast recovery silicon diode for use in AC motor controllers, originally developed for NASA for use in avionics power supplies, is presented. The diode utilizes a positive bevel PIN mesa structure with glass passivation and has the following characteristics: peak inverse voltage - 1200 volts, forward voltage at 50 amperes - 1.5 volts, reverse recovery time of 200 nanoseconds. Characterization data for the diode, included in a table, show agreement with design concepts developed for power diodes. Circuit diagrams of the diode are also given.

  3. Scalar control on speed drive for ac motor

    NASA Astrophysics Data System (ADS)

    Barsoum, Nader

    2012-11-01

    This paper aims to investigate the performance of ABB ACS800 variable speed drive operating under Scalar Control mode, and eventually develop a set of experimental procedures for undergraduate laboratory purposes. Scalar Control is the most widespread form of ac drive, for its low cost and simplicity especially implemented in the open loop mode. Scalar control is achieved by controlling the stator voltage and frequency, thus maintaining the motor's air-gap flux at a constant value. To illustrate the control method, the ac drive is configured according to the wiring diagram in the firmware manual that the drive control location can be both local and external. The drive is selected to operate under Factory application macro, whereby either ordinary speed control applications or constant speeds applications may be used. Under ordinary speed control, frequency reference signals are provided to the drive through the analogue input AI1. The drive will operate at the given frequency reference value throughout the operation regardless of any changes in the load. The torque speed curve moves along the speed axis with no changes to the shape as the supply frequencies changes. On the other hand, the drive allows three preset constant speed through digital inputs DI5 and DI6. The drive operate at a constant speed value over a time period, and only switch from one constant speed to another constant speed by triggering the two input switches. Scalar control is most suitable for applications not required high precision, such as blowers, fans and pumps.

  4. System and method for determining stator winding resistance in an AC motor

    DOEpatents

    Lu, Bin; Habetler, Thomas G.; Zhang, Pinjia; Theisen, Peter J.

    2011-05-31

    A system and method for determining stator winding resistance in an AC motor is disclosed. The system includes a circuit having an input connectable to an AC source and an output connectable to an input terminal of an AC motor. The circuit includes at least one contactor and at least one switch to control current flow and terminal voltages in the AC motor. The system also includes a controller connected to the circuit and configured to modify a switching time of the at least one switch to create a DC component in an output of the system corresponding to an input to the AC motor and determine a stator winding resistance of the AC motor based on the injected DC component of the voltage and current.

  5. Prospects for Brushless ac Motors with HTS Rotors

    NASA Astrophysics Data System (ADS)

    McCulloch, M. D.; Jim, K.; Kawai, Y.; Dew-Hughes, D.; Morgan, C.; Goringe, M. J.; Grovenor, C. R. M.

    1997-03-01

    There is a superconducting equivalent for every type of brushless ac motor; permanent magnet, reluctance, hysteresis and induction (squirrel cage) motor. The particular advantage of superconducting versions of these machines is that they are expected to provide much higher power densities than their conventional equivalents. The behaviour of superconducting rotors fabricated in the form of (a) squirrell cages from silver coated with melt-processed Bi-2212, (b) tubes cast centifugally from Bi-2212, and (c) small cylinders of melt-processed and seeded YBCO has been studied in rotating magnetic fields provided by conventional motor coils. Measurements of static torque, and values of dynamic torque deduced from angular velocity and acceleration have been used to characterise the potential performance of these embryonic machines. Two broad types of behaviour have been observed. In the Bi-2212 rotors the torque decreases with increasing rotor speed; this behaviour is believed due to flux creep. By contrast the strong-pinning YBCO rotors maintain a constant torque up to synchronous speed. Mathematical modelling of flux penetration and distribution within the rotors is able to reproduce both types of the observed behaviour. Power densities some 5 to 10 times that of conventional machines are predicted to be achievable in optimised prototype machines.

  6. HYDRAULIC SERVO

    DOEpatents

    Wiegand, D.E.

    1962-05-01

    A hydraulic servo is designed in which a small pressure difference produced at two orifices by an electrically operated flapper arm in a constantly flowing hydraulic loop is hydraulically amplified by two constant flow pumps, two additional orifices, and three unconnected ball pistons. Two of the pistons are of one size and operate against the additional orifices, and the third piston is of a different size and operates between and against the first two pistons. (AEC)

  7. Variable frequency inverter for ac induction motors with torque, speed and braking control

    NASA Technical Reports Server (NTRS)

    Nola, F. J. (Inventor)

    1975-01-01

    A variable frequency inverter was designed for driving an ac induction motor which varies the frequency and voltage to the motor windings in response to varying torque requirements for the motor so that the applied voltage amplitude and frequency are of optimal value for any motor load and speed requirement. The slip frequency of the motor is caused to vary proportionally to the torque and feedback is provided so that the most efficient operating voltage is applied to the motor. Winding current surge is limited and a controlled negative slip causes motor braking and return of load energy to a dc power source.

  8. Improved transistorized AC motor controller for battery powered urban electric passenger vehicles

    NASA Technical Reports Server (NTRS)

    Peak, S. C.

    1982-01-01

    An ac motor controller for an induction motor electric vehicle drive system was designed, fabricated, tested, evaluated, and cost analyzed. A vehicle performance analysis was done to establish the vehicle tractive effort-speed requirements. These requirements were then converted into a set of ac motor and ac controller requirements. The power inverter is a three-phase bridge using power Darlington transistors. The induction motor was optimized for use with an inverter power source. The drive system has a constant torque output to base motor speed and a constant horsepower output to maximum speed. A gear shifting transmission is not required. The ac controller was scaled from the base 20 hp (41 hp peak) at 108 volts dec to an expanded horsepower and battery voltage range. Motor reversal was accomplished by electronic reversal of the inverter phase sequence. The ac controller can also be used as a boost chopper battery charger. The drive system was tested on a dynamometer and results are presented. The current-controlled pulse width modulation control scheme yielded improved motor current waveforms. The ac controller favors a higher system voltage.

  9. Proposal of Current Control Method for High-Speed AC Motor System

    NASA Astrophysics Data System (ADS)

    Furutani, Shinichi; Satake, Akira

    In this paper, current control method for High-Speed AC Motor System is proposed. In High-Speed driving operation, Current controller tends to lose stability because of dead time caused by computational delay and Electromagnetic coupling included AC Motor Model. The Main purpose of the proposed method is reduction of dead time on current controller. Proposed method based model predictive control and optimizing of start timing. The Effectiveness of proposed method is confirmed by simulation results.

  10. Improved transistorized ac motor controller for battery powered urban electric passenger vehicles

    SciTech Connect

    Peak, S.C.

    1982-09-01

    The objectives of this program for an improved ac motor controller for battery powered urban electric passenger vehicles were: the design, fabrication, test, evaluation and cost analysis of an engineering model controller for an ac induction motor drive system, the investigation of a power level expansion to a family of horsepower and battery system voltages, and the investigation of the applicability of the ac controller for use as an on-board battery charger and for providing the function of motor reversal. Additional vehicle specifications, e.g., acceleration and pulling out of potholes, were added to the NASA vehicle specifications. Then, a vehicle performance analysis was done to establish the vehicle tractive effort-speed requirements. These requirements were then converted into a set of ac motor and ac controller requirements. The General Electric ac induction motor used in the drive is optimized to operate as a vehicle traction motor with a pulse width modulated (PWM) inverter as a power source. The motor is nominally rated 20 hp and 41 hp peak. The power inverter design is a three-phase transistorized bridge configuration with feedback diodes. The transistors are a special design General Electric high-power Darlington transistor rated 450 volts and 200 amps. The battery system voltage chosen was 108 volts. The control strategy is a constant torque profile by PWM operation to base speed and a constant horsepower profile by square-wave operation to maximum speed. A gear shifting transmission is not required. An advanced current-controlled PWM technique is used to control the motor voltage. The primary feedback control is a motor angle control, with voltage and torque outer loop controls.

  11. Demodulation circuit for AC motor current spectral analysis

    DOEpatents

    Hendrix, Donald E.; Smith, Stephen F.

    1990-12-18

    A motor current analysis method for the remote, noninvasive inspection of electric motor-operated systems. Synchronous amplitude demodulation and phase demodulation circuits are used singly and in combination along with a frequency analyzer to produce improved spectral analysis of load-induced frequencies present in the electric current flowing in a motor-driven system.

  12. Advanced servo manipulator

    DOEpatents

    Holt, W.E.; Kuban, D.P.; Martin, H.L.

    1988-10-25

    An advanced servo manipulator has modular parts. Modular motor members drive individual input gears to control shoulder roll, shoulder pitch, elbow pitch, wrist yaw, wrist pitch, wrist roll, and tong spacing. The modules include a support member, a shoulder module for controlling shoulder roll, and a sleeve module attached to the shoulder module in fixed relation thereto. The shoulder roll sleeve module has an inner cylindrical member rotatable relative to the outer cylindrical member, and upon which a gear pod assembly is mounted. A plurality of shafts are driven by the gears, which are in turn driven by individual motor modules to transmit rotary power to control elbow pitch as well as to provide four different rotary shafts across the bendable elbow joint to supply rotary motive power to a wrist member and tong member. 41 figs.

  13. Advanced servo manipulator

    DOEpatents

    Holt, William E.; Kuban, Daniel P.; Martin, H. Lee

    1988-01-01

    An advanced servo manipulator has modular parts. Modular motor members drive individual input gears to control shoulder roll, shoulder pitch, elbow pitch, wrist yaw, wrist pitch, wrist roll, and tong spacing. The modules include a support member, a shoulder module for controlling shoulder roll, and a sleeve module attached to the shoulder module in fixed relation thereto. The shoulder roll sleeve module has an inner cylindrical member rotatable relative to the outer cylindrical member, and upon which a gear pod assembly is mounted. A plurality of shafts are driven by the gears, which are in turn driven by individual motor modules to transmit rotary power to control elbow pitch as well as to provide four different rotary shafts across the bendable elbow joint to supply rotary motive power to a wrist member and tong member.

  14. Advanced AC permanent magnet axial flux disc motor for electric passenger vehicle

    NASA Technical Reports Server (NTRS)

    Kliman, G. B.

    1982-01-01

    An ac permanent magnet axial flux disc motor was developed to operate with a thyristor load commutated inverter as part of an electric vehicle drive system. The motor was required to deliver 29.8 kW (40 hp) peak and 10.4 kW (14 hp) average with a maximum speed of 11,000 rpm. It was also required to run at leading power factor to commutate the inverter. Three motors were built.

  15. Ac hysteresis loop measurement of stator-tooth in induction motor

    SciTech Connect

    Son, D.

    1999-09-01

    The properties of ac hysteresis loop of a stator tooth in a 5 hp induction motor was measured and analyzed. The load increase on the motor decreased magnetic induction, however increase the minor hysteresis loops in the high induction region. This effect caused increase in the core loss. Depending on condition of the motor, the core loss of the stator tooth can be 50% greater than the core loss under sinusoidal magnetic induction waveform.

  16. System and method for monitoring and controlling stator winding temperature in a de-energized AC motor

    DOEpatents

    Lu, Bin; Luebke, Charles John; Habetler, Thomas G.; Zhang, Pinjia; Becker, Scott K.

    2011-12-27

    A system and method for measuring and controlling stator winding temperature in an AC motor while idling is disclosed. The system includes a circuit having an input connectable to an AC source and an output connectable to an input terminal of a multi-phase AC motor. The circuit further includes a plurality of switching devices to control current flow and terminal voltages in the multi-phase AC motor and a controller connected to the circuit. The controller is configured to activate the plurality of switching devices to create a DC signal in an output of the motor control device corresponding to an input to the multi-phase AC motor, determine or estimate a stator winding resistance of the multi-phase AC motor based on the DC signal, and estimate a stator temperature from the stator winding resistance. Temperature can then be controlled and regulated by DC injection into the stator windings.

  17. Quick-scanning x-ray absorption spectroscopy system with a servo-motor-driven channel-cut monochromator with a temporal resolution of 10 ms

    SciTech Connect

    Nonaka, T.; Dohmae, K.; Araki, T.; Hayashi, Y.; Hirose, Y.; Uruga, T.; Yamazaki, H.; Tanida, H.; Goto, S.

    2012-08-15

    We have developed a quick-scanning x-ray absorption fine structure (QXAFS) system and installed it at the recently constructed synchrotron radiation beamline BL33XU at the SPring-8. Rapid acquisition of high-quality QXAFS data was realized by combining a servo-motor-driven Si channel-cut monochromator with a tapered undulator. Two tandemly aligned monochromators with channel-cut Si(111) and Si(220) crystals covered energy ranges of 4.0-28.2 keV and 6.6-46.0 keV, respectively. The system allows the users to adjust instantly the energy ranges of scans, the starting angles of oscillations, and the frequencies. The channel-cut crystals are cooled with liquid nitrogen to enable them to withstand the high heat load from the undulator radiation. Deformation of the reflecting planes is reduced by clamping each crystal with two cooling blocks. Performance tests at the Cu K-edge demonstrated sufficiently high data quality for x-ray absorption near-edge structure and extended x-ray absorption fine-structure analyses with temporal resolutions of up to 10 and 25 ms, respectively.

  18. Quick-scanning x-ray absorption spectroscopy system with a servo-motor-driven channel-cut monochromator with a temporal resolution of 10 ms

    NASA Astrophysics Data System (ADS)

    Nonaka, T.; Dohmae, K.; Araki, T.; Hayashi, Y.; Hirose, Y.; Uruga, T.; Yamazaki, H.; Mochizuki, T.; Tanida, H.; Goto, S.

    2012-08-01

    We have developed a quick-scanning x-ray absorption fine structure (QXAFS) system and installed it at the recently constructed synchrotron radiation beamline BL33XU at the SPring-8. Rapid acquisition of high-quality QXAFS data was realized by combining a servo-motor-driven Si channel-cut monochromator with a tapered undulator. Two tandemly aligned monochromators with channel-cut Si(111) and Si(220) crystals covered energy ranges of 4.0-28.2 keV and 6.6-46.0 keV, respectively. The system allows the users to adjust instantly the energy ranges of scans, the starting angles of oscillations, and the frequencies. The channel-cut crystals are cooled with liquid nitrogen to enable them to withstand the high heat load from the undulator radiation. Deformation of the reflecting planes is reduced by clamping each crystal with two cooling blocks. Performance tests at the Cu K-edge demonstrated sufficiently high data quality for x-ray absorption near-edge structure and extended x-ray absorption fine-structure analyses with temporal resolutions of up to 10 and 25 ms, respectively.

  19. EFFICIENCY OPTIMIZATION CONTROL OF AC INDUCTION MOTORS: INITIAL LABORATORY RESULTS

    EPA Science Inventory

    The report discusses the development of a fuzzy logic, energy-optimizing controller to improve the efficiency of motor/drive combinations that operate at varying loads and speeds. his energy optimizer is complemented by a sensorless speed controller that maintains motor shaft rev...

  20. EFFICIENCY OPTIMIZATIN CONTROL OF AC INDUCTION MOTORS: INITIAL LABORATORY RESULTS

    EPA Science Inventory

    The report discusses the development of a fuzzy logic, energy-optimizing controller to improve the efficiency of motor/drive combinations that operate at varying loads and speeds. This energy optimizer is complemented by a sensorless speed controller that maintains motor shaft re...

  1. Design of a novel phase-decoupling permanent magnet brushless ac motor

    NASA Astrophysics Data System (ADS)

    Cui, Wei; Chau, K. T.; Jiang, J. Z.; Fan, Ying

    2005-05-01

    This paper presents a phase-decoupling permanent magnet brushless ac motor which can offer better controllability, faster response, and smoother torque than its counterparts. The key is due to its different motor configuration and simple scalar control. The motor configuration is so unique that it inherently offers the features of phase decoupling, flux focusing, and flux shaping, hence achieving independent phase control, fast response, and smooth torque. The scalar control is fundamentally different from the complicated vector control. It can achieve direct torque control through independent control of the phase currents. The proposed motor is prototyped and experimentally verified.

  2. Construction of AC Motor Controllers for NOvA Experiment Upgrades

    SciTech Connect

    Cooley, Patrick; /Fermilab

    2011-08-04

    I have been constructing Alternating Current (AC) motor controllers for manipulation of particle beam detectors. The capability and reliability of these motor controllers are essential to the Laboratory's mission of accurate analysis of the particle beam's position. The device is moved in and out of the beam's path by the motor controller followed by the Neutrinos at the Main Injector Off-Axis {nu}{sub e} Appearance (NOvA) Experiment further down the beam pipe. In total, I built and tested ten ac motor controllers for new beam operations in the NOvA experiment. These units will prove to be durable and provide extremely accurate beam placement for NOvA Experiment far into the future.

  3. Effective method to measure back emfs and their harmonics of permanent magnet ac motors

    NASA Astrophysics Data System (ADS)

    Jiang, Q.; Bi, C.; Lin, S.

    2006-04-01

    As the HDD spindle motors become smaller and smaller, the back electromotive forces (emfs) measurement faces the new challenges due to their low inertias and small sizes. This article proposes a novel method to measure the back emfs and their harmonic components of PM ac motors only through a freewheeling procedure. To eliminate the influence of the freewheeling deceleration, the phase flux linkages are employed to obtain the back emf amplitudes and phases of the fundamental and harmonic components by using finite Fourier series analysis. The proposed method makes the freewheeling measurement of the back emfs and their harmonics accurate and fast. It is especially useful for the low inertia PM ac motors, such as spindle motors for small form factor HDDs.

  4. A.C. motors for high-performance drives: A design-based comparison

    SciTech Connect

    Vagati, A.; Fratta, A.; Franceschini, G.; Rosso, P.M.

    1995-12-31

    Three AC motors are compared, for application in high-performance controlled drives: induction, brushless and synchronous reluctance motors. Their design is optimized, under common design assumptions. Then, the given stall-torques are compared to each other. In addition, the quadrature reactances are compared, as affecting overload and flux-weakening performances. Last, applicative considerations are given, thus defining the most suitable solution for each field.

  5. Superconducting AC motor for centrifugal liquid helium pump

    SciTech Connect

    Rivetti, A.; Goria, R.; Martini, G.

    1982-01-01

    The behavior of flowmeters in liquid and supercritical helium is studied. A description is given of the motor and experimental apparatus. The initial results (torque vs. efficiency and power vs. slip) are chartered. The results obtained with an external rotating shield (torque vs. efficiency and power vs. slip) are also charted. One rotor provided a higher power particularly at the highest frequencies, provided that the critical point is not exceeded. Another rotor gives a better efficiency, particularly at the lowest frequencies. Recommendations for adopting a rotor design are given.

  6. AC motor and generator requirements for isolated WECS

    NASA Technical Reports Server (NTRS)

    Park, G. L.; Mccleer, P. J.; Hanson, B.; Weinberg, B.; Krauss, O.

    1985-01-01

    After surveying electrically driven loads used on productive farms, the investigators chose three pumps for testing at voltages and frequencies far outside the normal operating range. These loads extract and circulate water and move heat via air, and all are critical to farm productivity. The object was to determine the envelope of supply voltage and frequency over which these loads would operate stably for time intervals under 1 hour. This information is among that needed to determine the feasibility of supplying critical loads, in case of a utility outage, from a wind driven alternator whose output voltage and frequency will vary dramatically in most continental wind regimes. Other related work is surveyed. The salient features and limitations of the test configurations used and the data reduction are described. The development of simulation models suitable for a small computer are outlined. The results are primarily displayed on the voltage frequency plane with the general conclusion that the particular pump models considered will operate over the range of 50 to 90 Hz and a voltage band which starts below rated, decreases as frequency decreases, and is limited on the high side by excessive motor heating. For example, centrifugal pump operating voltage ranges as extensive .4 to 1.4 appear possible. Particular problems with starting, stalling due to lack of motor torque, high speed cavitation, and likely overheating are addressed in a listing of required properties for wind driven alternators and their controllers needed for use in the isolated or stand alone configuration considered.

  7. AC motor and generator requirements for isolated WECS

    NASA Astrophysics Data System (ADS)

    Park, G. L.; McCleer, P. J.; Hanson, B.; Weinberg, B.; Krauss, O.

    1985-10-01

    After surveying electrically driven loads used on productive farms, the investigators chose three pumps for testing at voltages and frequencies far outside the normal operating range. These loads extract and circulate water and move heat via air, and all are critical to farm productivity. The object was to determine the envelope of supply voltage and frequency over which these loads would operate stably for time intervals under 1 hour. This information is among that needed to determine the feasibility of supplying critical loads, in case of a utility outage, from a wind driven alternator whose output voltage and frequency will vary dramatically in most continental wind regimes. Other related work is surveyed. The salient features and limitations of the test configurations used and the data reduction are described. The development of simulation models suitable for a small computer are outlined. The results are primarily displayed on the voltage frequency plane with the general conclusion that the particular pump models considered will operate over the range of 50 to 90 Hz and a voltage band which starts below rated, decreases as frequency decreases, and is limited on the high side by excessive motor heating. For example, centrifugal pump operating voltage ranges as extensive .4 to 1.4 appear possible. Particular problems with starting, stalling due to lack of motor torque, high speed cavitation, and likely overheating are addressed in a listing of required properties for wind driven alternators and their controllers needed for use in the isolated or stand alone configuration considered.

  8. Improved SCR ac Motor Controller for Battery Powered Urban Electric Vehicles

    NASA Technical Reports Server (NTRS)

    Latos, T. S.

    1982-01-01

    An improved ac motor controller, which when coupled to a standard ac induction motor and a dc propulsion battery would provide a complete electric vehicle power train with the exception of the mechanical transmission and drive wheels was designed. In such a system, the motor controller converts the dc electrical power available at the battery terminals to ac electrical power for the induction motor in response to the drivers commands. The performance requirements of a hypothetical electric vehicle with an upper weight bound of 1590 kg (3500 lb) were used to determine the power rating of the controller. Vehicle acceleration capability, top speed, and gradeability requisites were contained in the Society of Automotive Engineers (SAE) Schedule 227a(d) driving cycle. The important capabilities contained in this driving cycle are a vehicle acceleration requirement of 0 to 72.4 kmph (0 to 45 mph) in 28 seconds a top speed of 88.5 kmph (55 mph), and the ability to negotiate a 10% grade at 48 kmph (30 mph). A 10% grade is defined as one foot of vertical rise per 10 feet of horizontal distance.

  9. Research on phase locked loop in optical memory servo system

    NASA Astrophysics Data System (ADS)

    Qin, Liqin; Ma, Jianshe; Zhang, Jianyong; Pan, Longfa; Deng, Ming

    2005-09-01

    Phase locked loop (PLL) is a closed loop automatic control system, which can track the phase of input signal. It widely applies in each area of electronic technology. This paper research the phase locked loop in optical memory servo area. This paper introduces the configuration of digital phase locked loop (PLL) and phase locked servo system, the control theory, and analyses system's stability. It constructs the phase locked loop experiment system of optical disk spindle servo, which based on special chip. DC motor is main object, this system adopted phase locked servo technique and digital signal processor (DSP) to achieve constant linear velocity (CLV) in controlling optical spindle motor. This paper analyses the factors that affect the stability of phase locked loop in spindle servo system, and discusses the affection to the optical disk readout signal and jitter due to the stability of phase locked loop.

  10. Magnetic particle clutch controls servo system

    NASA Technical Reports Server (NTRS)

    Fow, P. B.

    1973-01-01

    Magnetic clutches provide alternative means of driving low-power rate or positioning servo systems. They may be used over wide variety of input speed ranges and weigh comparatively little. Power drain is good with overall motor/clutch efficiency greater than 50 percent, and gain of clutch is close to linear, following hysteresis curve of core and rotor material.

  11. HYDRAULIC SERVO CONTROL MECHANISM

    DOEpatents

    Hussey, R.B.; Gottsche, M.J. Jr.

    1963-09-17

    A hydraulic servo control mechanism of compact construction and low fluid requirements is described. The mechanism consists of a main hydraulic piston, comprising the drive output, which is connected mechanically for feedback purposes to a servo control piston. A control sleeve having control slots for the system encloses the servo piston, which acts to cover or uncover the slots as a means of controlling the operation of the system. This operation permits only a small amount of fluid to regulate the operation of the mechanism, which, as a result, is compact and relatively light. This mechanism is particuiarly adaptable to the drive and control of control rods in nuclear reactors. (auth)

  12. Method and apparatus for pulse width modulation control of an AC induction motor

    DOEpatents

    Geppert, Steven; Slicker, James M.

    1984-01-01

    An inverter is connected between a source of DC power and a three-phase AC induction motor, and a micro-processor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .THETA., where .THETA. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands of electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a "flyback" DC-DC converter circuit for recharging the battery.

  13. Dynamic model tracking design for low inertia, high speed permanent magnet ac motors.

    PubMed

    Stewart, P; Kadirkamanathan, V

    2004-01-01

    Permanent magnet ac (PMAC) motors have existed in various configurations for many years. The advent of rare-earth magnets and their associated highly elevated levels of magnetic flux makes the permanent magnet motor attractive for many high performance applications from computer disk drives to all electric racing cars. The use of batteries as a prime storage element carries a cost penalty in terms of the unladen weight of the vehicle. Minimizing this cost function requires the minimum electric motor size and weight to be specified, while still retaining acceptable levels of output torque. This tradeoff can be achieved by applying a technique known as flux weakening which will be investigated in this paper. The technique allows the speed range of a PMAC motor to be greatly increased, giving a constant power range of more than 4:1. A dynamic model reference controller is presented which has advantages in ease of implementation, and is particularly suited to dynamic low inertia applications such as clutchless gear changing in high performance electric vehicles. The benefits of this approach are to maximize the torque speed envelope of the motor, particularly advantageous when considering low inertia operation. The controller is examined experimentally, confirming the predicted performance. PMID:15000141

  14. Method and apparatus for pulse width modulation control of an AC induction motor

    NASA Technical Reports Server (NTRS)

    Geppert, Steven (Inventor); Slicker, James M. (Inventor)

    1984-01-01

    An inverter is connected between a source of DC power and a three-phase AC induction motor, and a micro-processor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .THETA., where .THETA. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands of electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a flyback DC-DC converter circuit for recharging the battery.

  15. Implementation of damped-oscillation crane control for existing ac induction motor-driven cranes

    SciTech Connect

    Noakes, M.W.; Kress, R.L.; Appleton, G.T.

    1993-04-01

    The Oak Ridge National Laboratory (ORNL) has implemented damped-oscillation crane control on one of its existing ac induction motor-driven facility overhead cranes. The purpose of this engineering grade test has been to determine feasibility, determine control and interfacing specifications, and establish the capability of newly available ac motor-control hardware. A flux vector inverter drive is used in the initial demonstration to investigate acceptability for swing-free crane control. Motor performance and restrictions are also examined. Control hardware design is based upon the Environmental Restoration and Waste Management (ER&WM) Robotics Technology Development Program (RTDP) standards. This includes the use of the VME bus and Motorola 680X0-based CPU boards for the hardware and UNIX and VxWorks for the software. However, smaller, cheaper, and more simple embedded controller design constraints are also considered in order to make the technology more attractive for general industrial use. Theoretical background, specific implementation, and recommendations are presented in this paper.

  16. Implementation of damped-oscillation crane control for existing ac induction motor-driven cranes

    SciTech Connect

    Noakes, M.W.; Kress, R.L. ); Appleton, G.T. . School of Electrical Engineering)

    1993-01-01

    The Oak Ridge National Laboratory (ORNL) has implemented damped-oscillation crane control on one of its existing ac induction motor-driven facility overhead cranes. The purpose of this engineering grade test has been to determine feasibility, determine control and interfacing specifications, and establish the capability of newly available ac motor-control hardware. A flux vector inverter drive is used in the initial demonstration to investigate acceptability for swing-free crane control. Motor performance and restrictions are also examined. Control hardware design is based upon the Environmental Restoration and Waste Management (ER WM) Robotics Technology Development Program (RTDP) standards. This includes the use of the VME bus and Motorola 680X0-based CPU boards for the hardware and UNIX and VxWorks for the software. However, smaller, cheaper, and more simple embedded controller design constraints are also considered in order to make the technology more attractive for general industrial use. Theoretical background, specific implementation, and recommendations are presented in this paper.

  17. Sensorless speed estimation of an AC induction motor by using an artificial neural network approach

    NASA Astrophysics Data System (ADS)

    Alkhoraif, Abdulelah Ali

    Sensorless speed detection of an induction motor is an attractive area for researchers to enhance the reliability of the system and to reduce the cost of the components. This paper presents a simple method of estimating a rotational speed by utilizing an artificial neural network (ANN) that would be fed by a set of stator current frequencies that contain some saliency harmonics. This approach allows operators to detect the speed in induction motors such an approach also provides reliability, low cost, and simplicity. First, the proposed method is based on converting the stator current signals to the frequency domain and then applying a tracking algorithm to the stator current spectrum in order to detect frequency peaks. Secondly, the ANN has to be trained by the detected peaks; the training data must be from very precise data to provide an accurate rotor speed. Moreover, the desired output of the training is the speed, which is measured by a tachometer simultaneously with the stator current signal. The databases were collected at many different speeds from two different types of AC induction motors, wound rotor and squirrel cage. They were trained and tested, so when the difference between the desired speed value and the ANN output value reached the wanted accuracy, the system does not need to use the tachometer anymore. Eventually, the experimental results show that in an optimal ANN design, the speed of the wound rotor induction motor was estimated accurately, where the testing average error was 1 RPM. The proposed method has not succeeded to predict the rotor speed of the squirrel cage induction motor precisely, where the smallest testing­average error that was achieved was 5 RPM.

  18. Coupling an induction motor type generator to ac power lines. [making windmill generators compatible with public power lines

    NASA Technical Reports Server (NTRS)

    Nola, F. J. (Inventor)

    1984-01-01

    A system for coupling an induction motor type generator to an A.C. power line includes an electronic switch means that is controlled by a control system and is regulated to turn on at a relatively late point in each half cycle of its operation. The energizing power supplied by the line to the induction motor type generator is decreased and the net power delivered to the line is increased.

  19. Modeling and damping of high-frequency leakage currents in PWM inverter-fed AC motor drive systems

    SciTech Connect

    Ogasawara, Satoshi; Akagi, Hirofumi

    1995-12-31

    This paper presents an equivalent circuit for high-frequency leakage currents in PWM inverter-fed ac motors, which forms a series resonant circuit. The analysis based on the equivalent circuit leads to such a conclusion that the connection of a conventional common-mode choke or reactor in series between the ac terminals of a PWM inverter and those of an ac motor is not effective to reduce the rms and average values of the leakage current, but effective to reduce the peak value. Furthermore, this paper proposes a common-mode transformer which is different in damping principle from the conventional common-mode choke. It is shown theoretically and experimentally that the common-mode transformer is able to reduce the rms value of the leakage current to 25%, where the core used in the common-mode transformer is smaller than that of the conventional common-mode choke.

  20. Anti-Windup Algorithm with Priority to Proportinal Control Output of Speed PI Controller for Position Servo System

    NASA Astrophysics Data System (ADS)

    Sazawa, Masaki; Yamada, Takahiro; Ohishi, Kiyoshi; Katsura, Seiichiro

    A robust servo system is important for performance improvement of motion control system in several industry applications. Generally, a high speed positioning servo system consists of robust control systems with integrator, such as PI controller. The industrial servo system always has the limitation for the capacity of actuator and power amplifier. An ordinary industrial position servo system often has the saturation of motor current and motor speed. It is difficult for the high speed positioning servo system to keep the robust position control against the saturation of motor current and motor speed. Because, an ordinary position servo system has the complicated control structure with many control loops. Hence, it sometimes has the large overshoot and the oscillated response by the limitation of motor current and motor speed. In order to overcome this problem, this paper proposes a new robust high speed positioning servo system considering the saturation of torque current and motor speed. The experimental results show that the proposed robust high speed positioning servo system the quick and stable position response for the saturation of motor current and motor speed.

  1. Design single-motor AC drive for energy savings in centrifugal applications

    SciTech Connect

    Not Available

    1982-06-01

    This article is an evaluation of a single- motor with AC drive that saves energy with increased efficiency and reliability in a wide variety of pump, fan, compressor, and other centrifugal applications. Drives deliver adjustable speed for adjustable flow and will satisfy a number of particular objectives. A principal benefit of the drive is its efficiency. The drives also offer regenerative capability without modification, built-in memory for first-fault indication, and easy troubleshooting with comprehensive self-diagnostics. The drive controls flow in centrifugal applications by adjusting the pumps or fan speed. This provides energy savings over conventional flow control systems. Slip devices, also used to produce variable speed in centrifugal equipment, vary the ''slip'' between the constant-speed motor shaft and the pump or fan shaft. The speed which is not transmitted is dissipated as heat within the slip device itself. The drives are available from stock (100-250 hp) for immediate energy savings on both new and retrofit spplications, with a number of standard features: a remote operator control station provides start-stop and speed selection; acceleration/deceleration are separately adjustable over a range of 2.5 to 35 seconds with 5- to 70-second range available using simple jumper selection; and a coast-to-rest is also available using simple jumper selection. The drive can be operated automatically from an ungrounded 4-20 mA process control signal.

  2. Direct drive digital servo press with high parallel control

    NASA Astrophysics Data System (ADS)

    Murata, Chikara; Yabe, Jun; Endou, Junichi; Hasegawa, Kiyoshi

    2013-12-01

    Direct drive digital servo press has been developed as the university-industry joint research and development since 1998. On the basis of this result, 4-axes direct drive digital servo press has been developed and in the market on April of 2002. This servo press is composed of 1 slide supported by 4 ball screws and each axis has linearscale measuring the position of each axis with high accuracy less than μm order level. Each axis is controlled independently by servo motor and feedback system. This system can keep high level parallelism and high accuracy even with high eccentric load. Furthermore the 'full stroke full power' is obtained by using ball screws. Using these features, new various types of press forming and stamping have been obtained by development and production. The new stamping and forming methods are introduced and 'manufacturing' need strategy of press forming with high added value and also the future direction of press forming are also introduced.

  3. Mixed Modulation Method of PWM Inverter by Considering Acceleration Torque and Voltage Saturation for Speed Servo System

    NASA Astrophysics Data System (ADS)

    Takahashi, Kenji; Ohishi, Kiyoshi; Kanmachi, Tosiyuki

    The speed servo system of an AC motor should always have a rapid and smooth response without current ripple. For this purpose, this paper proposes a new mixed modulation method of the PWM inverter by considering acceleration torque and voltage saturation. The rapid and robust speed servo system often has the high gain speed controller and the high gain current controller. In this case, this speed servo system often has the voltage saturation in the transient state. This paper discusses the amplitude and THD of output voltage on the condition of voltage saturation for each voltage modulation method of three phase inverter such as the carrier comparison inverter using the two phase modulation (2ph. M) and the space voltage vector modulation (SVM) inverter. The carrier comparison inverter using the 2ph. M has the large voltage with large harmonic current. The SVM inverter has the smooth voltage response with small harmonic current. The proposed method switches over the SVM and the 2ph. M methods properly by considering acceleration torque and voltage saturation. The experimental results confirm the effectiveness of the proposed mixed modulation method of the PWM inverter.

  4. Road load simulator tests of the Gould phase 1 functional model silicon controlled rectifier ac motor controller for electric vehicles

    NASA Technical Reports Server (NTRS)

    Gourash, F.

    1984-01-01

    The test results for a functional model ac motor controller for electric vehicles and a three-phase induction motor which were dynamically tested on the Lewis Research Center road load simulator are presented. Results show that the controller has the capability to meet the SAE-J227a D cycle test schedule and to accelerate a 1576-kg (3456-lb) simulated vehicle to a cruise speed of 88.5 km/hr (55 mph). Combined motor controller efficiency is 72 percent and the power inverter efficiency alone is 89 percent for the cruise region of the D cycle. Steady state test results for motoring, regeneration, and thermal data obtained by operating the simulator as a conventional dynamometer are in agreement with the contractor's previously reported data. The regeneration test results indicate that a reduction in energy requirements for urban driving cycles is attainable with regenerative braking. Test results and data in this report serve as a data base for further development of ac motor controllers and propulsion systems for electric vehicles. The controller uses state-of-the-art silicon controlled rectifier (SCR) power semiconductors and microprocessor-based logic and control circuitry. The controller was developed by Gould Laboratories under a Lewis contract for the Department of Energy's Electric and Hybrid Vehicle program.

  5. Road load simulator tests of the Gould phase 1 functional model silicon controlled rectifier ac motor controller for electric vehicles

    NASA Astrophysics Data System (ADS)

    Gourash, F.

    1984-02-01

    The test results for a functional model ac motor controller for electric vehicles and a three-phase induction motor which were dynamically tested on the Lewis Research Center road load simulator are presented. Results show that the controller has the capability to meet the SAE-J227a D cycle test schedule and to accelerate a 1576-kg (3456-lb) simulated vehicle to a cruise speed of 88.5 km/hr (55 mph). Combined motor controller efficiency is 72 percent and the power inverter efficiency alone is 89 percent for the cruise region of the D cycle. Steady state test results for motoring, regeneration, and thermal data obtained by operating the simulator as a conventional dynamometer are in agreement with the contractor's previously reported data. The regeneration test results indicate that a reduction in energy requirements for urban driving cycles is attainable with regenerative braking. Test results and data in this report serve as a data base for further development of ac motor controllers and propulsion systems for electric vehicles. The controller uses state-of-the-art silicon controlled rectifier (SCR) power semiconductors and microprocessor-based logic and control circuitry. The controller was developed by Gould Laboratories under a Lewis contract for the Department of Energy's Electric and Hybrid Vehicle program.

  6. A transputer-based adaptive speed controller for AC induction motor drives with load torque estimation

    SciTech Connect

    Tsai, M.F.; Tzou, Y.Y.

    1997-03-01

    In this paper, the authors design and implement an adaptive speed controller that can estimate load torque for ac induction motor drives employing a transputer-based parallel processing technique. The adaptive speed controller, which precedes the field-oriented control loop, consists of a two-degree-of-freedom controller and a feedforward load-torque compensator. The two-degree-of-freedom controller is designed by a pole-placement technique with polynomial manipulations. Its parameters are adjusted adaptively in terms of estimated model parameters. Estimating the model parameters entails a second-order least-squares estimator with constant trace to avoid estimator windup. The design of the feedforward compensator is based on an estimated load-torque model. Estimating the load torque entails a first-order least-squares estimator with variable forgetting factor and covariance resetting, the purposes of which are to detect any slow or sudden changes of torque disturbance, respectively. The resulting adaptive controller is implemented in parallel by IMS T800-20 transputers. Experimental results demonstrate the robustness of the proposed control method in contending with varying load and torque disturbance.

  7. Sensor-less pseudo-sinusoidal drive for a permanent-magnet brushless ac motor

    NASA Astrophysics Data System (ADS)

    Liu, Li-Hsiang; Chern, Tzuen-Lih; Pan, Ping-Lung; Huang, Tsung-Mou; Tsay, Der-Min; Kuang, Jao-Hwa

    2012-04-01

    The precise rotor-position information is required for a permanent-magnet brushless ac motor (BLACM) drive. In the conventional sinusoidal drive method, either an encoder or a resolver is usually employed. For position sensor-less vector control schemes, the rotor flux estimation and torque components are obtained by complicated coordinate transformations. These computational intensive methods are susceptible to current distortions and parameter variations. To simplify the method complexity, this work presents a sensor-less pseudo-sinusoidal drive scheme with speed control for a three-phase BLACM. Based on the sinusoidal drive scheme, a floating period of each phase current is inserted for back electromotive force detection. The zero-crossing point is determined directly by the proposed scheme, and the rotor magnetic position and rotor speed can be estimated simultaneously. Several experiments for various active angle periods are undertaken. Furthermore, a current feedback control is included to minimize and compensate the torque fluctuation. The experimental results show that the proposed method has a competitive performance compared with the conventional drive manners for BLACM. The proposed scheme is straightforward, bringing the benefits of sensor-less drive and negating the need for coordinate transformations in the operating process.

  8. Fast-Acting Electrohydraulic Servo

    NASA Technical Reports Server (NTRS)

    Webb, J. A. J.; Mehmed, O.; Lorenzo, C. F.

    1982-01-01

    Electrohydraulic servo controls moving elements of airflow valve. Position of moving element and attached piston is monitored by linear variable-differential transformer (LVDT). Single-stage servo valve lets fluid into and out of piston volume in response to feedback signals from the LVDT.

  9. Beta Band Transcranial Alternating (tACS) and Direct Current Stimulation (tDCS) Applied After Initial Learning Facilitate Retrieval of a Motor Sequence

    PubMed Central

    Krause, Vanessa; Meier, Anna; Dinkelbach, Lars; Pollok, Bettina

    2016-01-01

    The primary motor cortex (M1) contributes to the acquisition and early consolidation of a motor sequence. Although the relevance of M1 excitability for motor learning has been supported, the significance of M1 oscillations remains an open issue. This study aims at investigating to what extent retrieval of a newly learned motor sequence can be differentially affected by motor-cortical transcranial alternating (tACS) and direct current stimulation (tDCS). Alpha (10 Hz), beta (20 Hz) or sham tACS was applied in 36 right-handers. Anodal or cathodal tDCS was applied in 30 right-handers. Participants learned an eight-digit serial reaction time task (SRTT; sequential vs. random) with the right hand. Stimulation was applied to the left M1 after SRTT acquisition at rest for 10 min. Reaction times were analyzed at baseline, end of acquisition, retrieval immediately after stimulation and reacquisition after eight further sequence repetitions. Reaction times during retrieval were significantly faster following 20 Hz tACS as compared to 10 Hz and sham tACS indicating a facilitation of early consolidation. tDCS yielded faster reaction times, too, independent of polarity. No significant differences between 20 Hz tACS and tDCS effects on retrieval were found suggesting that 20 Hz effects might be associated with altered motor-cortical excitability. Based on the behavioral modulation yielded by tACS and tDCS one might speculate that altered motor-cortical beta oscillations support early motor consolidation possibly associated with neuroplastic reorganization. PMID:26834593

  10. An Approach to Suppressing Both Shaft Voltage and Leakage Current in an AC Motor Driven by a Voltage-Source PWM Inverter

    NASA Astrophysics Data System (ADS)

    Doumoto, Takafumi; Akagi, Hirofumi

    This paper proposes a practical approach to suppressing both shaft voltage and leakage current in an ac motor driven by a voltage-source PWM inverter. This approach is characterized by using a neutral line of the ac motor. A common-mode inductor is connected between the inverter and the motor. Moreover, a resistor and a capacitor are connected in series between the motor neutral point and the inverter negative dc bus. This unique circuit configuration makes the common-mode inductor effective in reducing the common-mode voltage appearing at the motor terminals. As a result, both shaft voltage and ground current are significantly suppressed with low cost. Over-voltages at the end of a cable can be suppressed by a normal-mode inductor and a resistor which are connected in parallel. The validity and effectiveness of the new approach are verified by experimental results from a 5-kVA laboratory system.

  11. Brake power servo booster

    SciTech Connect

    Kobayashi, M.; Shimamura, M.

    1988-04-19

    A brake power servo booster is described comprising: a power piston; a power piston return spring; at least two shells enclosing at least a portion of the power piston and defining a constant pressure chamber and a variable pressure chamber; a master cylinder for controlling the application of hydraulic pressure to a brake mechanism; an input shaft; a hollow cylindrical member integrally connected to the input shaft, a stopper member for limiting movement of the hollow cylindrical member in the second direction, a hollow output shaft integrally connected at one end thereof to the power piston; a connecting member integrally connected to the other end of the output shaft and slidably disposed inside the hollow cylindrical member, a valve member, a valve return spring for urging and valve member towards the first and second valve seats; and a key member provided between the connecting member and the hollow cylindrical member for allowing relative displacement between the connecting member and the hollow cylindrical member in the first and second directions within a predetermined range.

  12. Long-stroke fast tool servo and a tool setting method for freeform optics fabrication

    NASA Astrophysics Data System (ADS)

    Liu, Qiang; Zhou, Xiaoqin; Liu, Zhiwei; Lin, Chao; Ma, Long

    2014-09-01

    Diamond turning assisted by fast tool servo is of high efficiency for the fabrication of freeform optics. This paper describes a long-stroke fast tool servo to obtain a large-amplitude tool motion. It has the advantage of low cost and higher stiffness and natural frequency than other flexure-based long-stroke fast tool servo systems. The fast tool servo is actuated by a voice coil motor and guided by a flexure-hinge structure. Open-loop and close-loop control tests are conducted on the testing platform. While fast tool servo system is an additional motion axis for a diamond turning machine, a tool center adjustment method is described to confirm tool center position in the machine tool coordinate system when the fast tool servo system is fixed on the diamond turning machine. Last, a sinusoidal surface is machined and the results demonstrate that the tool adjustment method is efficient and precise for a flexure-based fast tool servo system, and the fast tool servo system works well on the fabrication of freeform optics.

  13. A Hydraulic Blowdown Servo System For Launch Vehicle

    NASA Astrophysics Data System (ADS)

    Chen, Anping; Deng, Tao

    2016-07-01

    This paper introduced a hydraulic blowdown servo system developed for a solid launch vehicle of the family of Chinese Long March Vehicles. It's the thrust vector control (TVC) system for the first stage. This system is a cold gas blowdown hydraulic servo system and consist of gas vessel, hydraulic reservoir, servo actuator, digital control unit (DCU), electric explosion valve, and pressure regulator etc. A brief description of the main assemblies and characteristics follows. a) Gas vessel is a resin/carbon fiber composite over wrapped pressure vessel with a titanium liner, The volume of the vessel is about 30 liters. b) Hydraulic reservoir is a titanium alloy piston type reservoir with a magnetostrictive sensor as the fluid level indicator. The volume of the reservoir is about 30 liters. c) Servo actuator is a equal area linear piston actuator with a 2-stage low null leakage servo valve and a linear variable differential transducer (LVDT) feedback the piston position, Its stall force is about 120kN. d) Digital control unit (DCU) is a compact digital controller based on digital signal processor (DSP), and deployed dual redundant 1553B digital busses to communicate with the on board computer. e) Electric explosion valve is a normally closed valve to confine the high pressure helium gas. f) Pressure regulator is a spring-loaded poppet pressure valve, and regulates the gas pressure from about 60MPa to about 24MPa. g) The whole system is mounted in the aft skirt of the vehicle. h) This system delivers approximately 40kW hydraulic power, by contrast, the total mass is less than 190kg. the power mass ratio is about 0.21. Have finished the development and the system test. Bench and motor static firing tests verified that all of the performances have met the design requirements. This servo system is complaint to use of the solid launch vehicle.

  14. Cortico-muscular coupling and motor performance are modulated by 20 Hz transcranial alternating current stimulation (tACS) in Parkinson’s disease

    PubMed Central

    Krause, Vanessa; Wach, Claudia; Südmeyer, Martin; Ferrea, Stefano; Schnitzler, Alfons; Pollok, Bettina

    2014-01-01

    Parkinson’s disease (PD) is associated with pathologically altered oscillatory activity. While synchronized oscillations between 13 and 30 Hz are increased within a cortico-subcortical network, cortico-muscular coupling (CMC) is decreased. The present study aims at investigating the effect of non-invasive transcranial alternating current stimulation (tACS) of the primary motor cortex (M1) on motor symptoms and motor-cortical oscillations in PD. In 10 PD patients and 10 healthy control subjects, static isometric contraction, dynamic fast finger tapping, and diadochokinesia of the more severely affected hand were investigated prior to and shortly after tACS of the contralateral M1 at 10 Hz vs. 20 Hz vs. sham. During isometric contraction, neuromagnetic activity was recorded using magnetoencephalography. 20 Hz tACS attenuated beta band CMC during isometric contraction and amplitude variability during finger tapping in PD patients but not in healthy control subjects. 10 Hz tACS yielded no significant after-effects. The present data suggest that PD is associated with pathophysiological alterations which abet a higher responsiveness toward frequency-specific tACS – possibly due to pathologically altered motor-cortical oscillatory synchronization at frequencies between 13 and 30 Hz. PMID:24474912

  15. Detecting servo failures with software

    NASA Technical Reports Server (NTRS)

    Lew, D.; Quam, R.

    1979-01-01

    Program detects hardware failure in servosystems by comparing actual servo valve position with predictions of software model. In addition, system will also pick up most computer input/output failures. Process presents faster and more reliable results than previous failure detection methods.

  16. Long range fast tool servo

    NASA Astrophysics Data System (ADS)

    Moorefield, G. M., II; Dow, Thomas A.; Falter, Karl J.; Ro, Paul I.

    1993-05-01

    The PEC's MAC 100 Fast Tool Servo (FTS) System has demonstrated the efficacy of fabricating off-axis parabolic segments on axis by utilizing a fast tool motion to machine non-rotationally symmetric surfaces. The key to this technique was a servo for the tool motion that had a high-bandwidth coupled with a small range of motion. The Keck telescope, with its thirty-six (36) 1-meter diameter segments, would have been an excellent application for this technology. Since this technology was not available at the time of construction, each mirror segment was fabricated to its desired shape by loading it to a specified deformed shape and polishing it to a spherical contour, then removing the bending loads to allow the segment to relax to the desired asymmetric shape. If the segments of this optic had been constructed on axis with an FTS, the fabrication of the most extreme segment would have required only about 200 micrometers of non-rotational symmetry. However, the demand for larger displacement actuators is being driven by new applications with nonrotationally symmetric components in the millimeter range. This report describes the search for a suitable actuator for a long range fast tool servo system that would allow the fabrication of non-rotationally symmetric optical surfaces with a 1 mm range of servo motion. To allow cost-effective machining of these surfaces, the actuator must also possess a 50 Hz bandwidth (minimum) and 25 nanometer resolution.

  17. Hydraulic servo control spool valve

    DOEpatents

    Miller, Donald M.

    1983-01-01

    A servo operated spool valve having a fixed sleeve and axially movable spool. The sleeve is machined in two halves to form a long, narrow tapered orifice slot across which a transverse wall of the spool is positioned. The axial position of the spool wall along the slot regulates the open orifice area with extreme precision.

  18. Superconductor-Mediated Modification of Gravity? AC Motor Experiments with Bulk YBCO Disks in Rotating Magnetic Fields

    NASA Technical Reports Server (NTRS)

    Noever, David A.; Koczor, Ronald J.; Roberson, Rick

    1998-01-01

    We have previously reported results using a high precision gravimeter to probe local gravity changes in the neighborhood of large bulk-processed high-temperature superconductors. Podkietnov, et al (Podkietnov, E. and Nieminen, R. (1992) A Possibility of Gravitational Force Shielding by Bulk YBa2 Cu3 O7-x Superconductor, Physica C, C203:441-444.) have indicated that rotating AC fields play an essential role in their observed distortion of combined gravity and barometric pressure readings. We report experiments on large (15 cm diameter) bulk YBCO ceramic superconductors placed in the core of a three-phase, AC motor stator. The applied rotating field produces up to a 12,000 revolutions per minute magnetic field. The field intensity decays rapidly from the maximum at the outer diameter of the superconducting disk (less than 60 Gauss) to the center (less than 10 Gauss). This configuration was applied with and without a permanent DC magnetic field levitating the superconducting disk, with corresponding gravity readings indicating an apparent increase in observed gravity of less than 1 x 10(exp -6)/sq cm, measured above the superconductor. No effect of the rotating magnetic field or thermal environment on the gravimeter readings or on rotating the superconducting disk was noted within the high precision of the observation. Implications for propulsion initiatives and power storage flywheel technologies for high temperature superconductors will be discussed for various spacecraft and satellite applications.

  19. Photoelectric radar servo control system based on ARM+FPGA

    NASA Astrophysics Data System (ADS)

    Wu, Kaixuan; Zhang, Yue; Li, Yeqiu; Dai, Qin; Yao, Jun

    2016-01-01

    In order to get smaller, faster, and more responsive requirements of the photoelectric radar servo control system. We propose a set of core ARM + FPGA architecture servo controller. Parallel processing capability of FPGA to be used for the encoder feedback data, PWM carrier modulation, A, B code decoding processing and so on; Utilizing the advantage of imaging design in ARM Embedded systems achieves high-speed implementation of the PID algorithm. After the actual experiment, the closed-loop speed of response of the system cycles up to 2000 times/s, in the case of excellent precision turntable shaft, using a PID algorithm to achieve the servo position control with the accuracy of + -1 encoder input code. Firstly, This article carry on in-depth study of the embedded servo control system hardware to determine the ARM and FPGA chip as the main chip with systems based on a pre-measured target required to achieve performance requirements, this article based on ARM chip used Samsung S3C2440 chip of ARM7 architecture , the FPGA chip is chosen xilinx's XC3S400 . ARM and FPGA communicate by using SPI bus, the advantage of using SPI bus is saving a lot of pins for easy system upgrades required thereafter. The system gets the speed datas through the photoelectric-encoder that transports the datas to the FPGA, Then the system transmits the datas through the FPGA to ARM, transforms speed datas into the corresponding position and velocity data in a timely manner, prepares the corresponding PWM wave to control motor rotation by making comparison between the position data and the velocity data setted in advance . According to the system requirements to draw the schematics of the photoelectric radar servo control system and PCB board to produce specially. Secondly, using PID algorithm to control the servo system, the datas of speed obtained from photoelectric-encoder is calculated position data and speed data via high-speed digital PID algorithm and coordinate models. Finally, a

  20. Small Autonomous Aircraft Servo Health Monitoring

    NASA Technical Reports Server (NTRS)

    Quintero, Steven

    2008-01-01

    Small air vehicles offer challenging power, weight, and volume constraints when considering implementation of system health monitoring technologies. In order to develop a testbed for monitoring the health and integrity of control surface servos and linkages, the Autonomous Aircraft Servo Health Monitoring system has been designed for small Uninhabited Aerial Vehicle (UAV) platforms to detect problematic behavior from servos and the air craft structures they control, This system will serve to verify the structural integrity of an aircraft's servos and linkages and thereby, through early detection of a problematic situation, minimize the chances of an aircraft accident. Embry-Riddle Aeronautical University's rotary-winged UAV has an Airborne Power management unit that is responsible for regulating, distributing, and monitoring the power supplied to the UAV's avionics. The current sensing technology utilized by the Airborne Power Management system is also the basis for the Servo Health system. The Servo Health system measures the current draw of the servos while the servos are in Motion in order to quantify the servo health. During a preflight check, deviations from a known baseline behavior can be logged and their causes found upon closer inspection of the aircraft. The erratic behavior nay include binding as a result of dirt buildup or backlash caused by looseness in the mechanical linkages. Moreover, the Servo Health system will allow elusive problems to be identified and preventative measures taken to avoid unnecessary hazardous conditions in small autonomous aircraft.

  1. Advanced single permanent magnet axipolar ironless stator ac motor for electric passenger vehicles

    NASA Technical Reports Server (NTRS)

    Beauchamp, E. D.; Hadfield, J. R.; Wuertz, K. L.

    1983-01-01

    A program was conducted to design and develop an advanced-concept motor specifically created for propulsion of electric vehicles with increased range, reduced energy consumption, and reduced life-cycle costs in comparison with conventional systems. The motor developed is a brushless, dc, rare-earth cobalt, permanent magnet, axial air gap inductor machine that uses an ironless stator. Air cooling is inherent provided by the centrifugal-fan action of the rotor poles. An extensive design phase was conducted, which included analysis of the system performance versus the SAE J227a(D) driving cycle. A proof-of-principle model was developed and tested, and a functional model was developed and tested. Full generator-level testing was conducted on the functional model, recording electromagnetic, thermal, aerodynamic, and acoustic noise data. The machine demonstrated 20.3 kW output at 1466 rad/s and 160 dc. The novel ironless stator demonstated the capability to continuously operate at peak current. The projected system performance based on the use of a transistor inverter is 23.6 kW output power at 1466 rad/s and 83.3 percent efficiency. Design areas of concern regarding electric vehicle applications include the inherently high windage loss and rotor inertia.

  2. Experimental implementation of a robust damped-oscillation control algorithm on a full-sized, two-degree-of-freedom, AC induction motor-driven crane

    NASA Astrophysics Data System (ADS)

    Kress, R. L.; Jansen, J. F.; Noakes, M. W.

    When suspended payloads are moved with an overhead crane, pendulum like oscillations are naturally introduced. This presents a problem any time a crane is used, especially when expensive and/or delicate objects are moved, when moving in a cluttered and/or hazardous environment, and when objects are to be placed in tight locations. Damped-oscillation control algorithms have been demonstrated over the past several years for laboratory-scale robotic systems on dc motor-driven overhead cranes. Most overhead cranes presently in use in industry are driven by ac induction motors; consequently, Oak Ridge National Laboratory has implemented damped-oscillation crane control on one of its existing facility ac induction motor-driven overhead cranes. The purpose of this test was to determine feasibility, to work out control and interfacing specifications, and to establish the capability of newly available ac motor control hardware with respect to use in damped-oscillation-controlled systems. Flux vector inverter drives are used to investigate their acceptability for damped-oscillation crane control. The purpose of this paper is to describe the experimental implementation of a control algorithm on a full-sized, two-degree-of-freedom, industrial crane; describe the experimental evaluation of the controller including robustness to payload length changes; explain the results of experiments designed to determine the hardware required for implementation of the control algorithms; and to provide a theoretical description of the controller.

  3. Experimental implementation of a robust damped-oscillation control algorithm on a full-sized, two-degree-of-freedom, AC induction motor-driven crane

    SciTech Connect

    Kress, R.L.; Jansen, J.F.; Noakes, M.W.

    1994-05-01

    When suspended payloads are moved with an overhead crane, pendulum like oscillations are naturally introduced. This presents a problem any time a crane is used, especially when expensive and/or delicate objects are moved, when moving in a cluttered an or hazardous environment, and when objects are to be placed in tight locations. Damped-oscillation control algorithms have been demonstrated over the past several years for laboratory-scale robotic systems on dc motor-driven overhead cranes. Most overhead cranes presently in use in industry are driven by ac induction motors; consequently, Oak Ridge National Laboratory has implemented damped-oscillation crane control on one of its existing facility ac induction motor-driven overhead cranes. The purpose of this test was to determine feasibility, to work out control and interfacing specifications, and to establish the capability of newly available ac motor control hardware with respect to use in damped-oscillation-controlled systems. Flux vector inverter drives are used to investigate their acceptability for damped-oscillation crane control. The purpose of this paper is to describe the experimental implementation of a control algorithm on a full-sized, two-degree-of-freedom, industrial crane; describe the experimental evaluation of the controller including robustness to payload length changes; explain the results of experiments designed to determine the hardware required for implementation of the control algorithms; and to provide a theoretical description of the controller.

  4. Comparison of a synergetic battery pack drive system to a pulse width modulated AC induction motor drive for an electric vehicle

    SciTech Connect

    Davis, A.; Salameh, Z.M.; Eaves, S.S.

    1999-06-01

    A new battery configuration technique and accompanying control circuitry, termed a Synergetic Battery Pack (SBP), is designed to work with Lithium batteries, and can be used as both an inverter for an electric vehicle AC induction motor drive and as a battery charger. In this paper, the performance of a Synergetic Battery Pack during motor drive operation is compared via computer simulation with a conventional motor drive which uses sinusoidal pulse width modulation (SPWM) to determine its effectiveness as a motor drive. The study showed that the drive efficiency was compatible with the conventional system, and offered a significant advantage in the lower frequency operating ranges. The voltage total harmonic distortion (THD) of the SBP was significantly lower than the PWM drive output, but the current THD was slightly higher due to the shape of the harmonic spectrum. In conclusion, the SBP is an effective alternative to a conventional drive, but the real advantage lies in its battery management capabilities and charger operation.

  5. Proposal of new structure of MgB 2 wires with low AC loss for stator windings of fully superconducting motors located in iron core slots

    NASA Astrophysics Data System (ADS)

    Kajikawa, K.; Osaka, R.; Kuga, H.; Nakamura, T.; Wakuda, T.

    2011-11-01

    The new structure of MgB 2 monofilamentary wires for stator windings of fully superconducting motors is proposed to reduce their AC losses in iron core slots for the application of an alternating transport current. In order to validate the proposed structure of wire for loss reduction, numerical calculations are carried out by means of a finite element method using edge elements formulated with a self-field due to currents induced in an analysis region. It is assumed that the voltage-current characteristics of the MgB 2 superconductor are given by Bean’s critical state model, in which the critical current density is independent of the local magnetic field. The influences of wire structures on the AC losses are discussed quantitatively toward the optimum design of stator windings in fully superconducting motors with the MgB 2 wires.

  6. Adjustable Speed Drive Project for Teaching a Servo Systems Course Laboratory

    ERIC Educational Resources Information Center

    Rodriguez-Resendiz, J.; Herrera-Ruiz, G.; Rivas-Araiza, E. A.

    2011-01-01

    This paper describes an adjustable speed drive for a three-phase motor, which has been implemented as a design for a servo system laboratory course in an engineering curriculum. The platform is controlled and analyzed in a LabVIEW environment and run on a PC. Theory is introduced in order to show the sensorless algorithms. These are computed by…

  7. Visual-servoing optical microscopy

    DOEpatents

    Callahan, Daniel E.; Parvin, Bahram

    2011-05-24

    The present invention provides methods and devices for the knowledge-based discovery and optimization of differences between cell types. In particular, the present invention provides visual servoing optical microscopy, as well as analysis methods. The present invention provides means for the close monitoring of hundreds of individual, living cells over time; quantification of dynamic physiological responses in multiple channels; real-time digital image segmentation and analysis; intelligent, repetitive computer-applied cell stress and cell stimulation; and the ability to return to the same field of cells for long-term studies and observation. The present invention further provides means to optimize culture conditions for specific subpopulations of cells.

  8. Visual-servoing optical microscopy

    DOEpatents

    Callahan, Daniel E.; Parvin, Bahram

    2009-06-09

    The present invention provides methods and devices for the knowledge-based discovery and optimization of differences between cell types. In particular, the present invention provides visual servoing optical microscopy, as well as analysis methods. The present invention provides means for the close monitoring of hundreds of individual, living cells over time: quantification of dynamic physiological responses in multiple channels; real-time digital image segmentation and analysis; intelligent, repetitive computer-applied cell stress and cell stimulation; and the ability to return to the same field of cells for long-term studies and observation. The present invention further provides means to optimize culture conditions for specific subpopulations of cells.

  9. Visual-servoing optical microscopy

    DOEpatents

    Callahan, Daniel E; Parvin, Bahram

    2013-10-01

    The present invention provides methods and devices for the knowledge-based discovery and optimization of differences between cell types. In particular, the present invention provides visual servoing optical microscopy, as well as analysis methods. The present invention provides means for the close monitoring of hundreds of individual, living cells over time; quantification of dynamic physiological responses in multiple channels; real-time digital image segmentation and analysis; intelligent, repetitive computer-applied cell stress and cell stimulation; and the ability to return to the same field of cells for long-term studies and observation. The present invention further provides means to optimize culture conditions for specific subpopulations of cells.

  10. Fast axis servo for the fast and precise machining of non-rotational symmetric optics

    NASA Astrophysics Data System (ADS)

    Tian, Fujing; Yin, Ziqiang; Li, Shengyi

    2014-08-01

    A new long range tool servo-fast axis servo is developed, which is used for fabricating the non-rotational symmetric optics surface with millimeters' sag. The mechanism design, motion modeling and development of FAS device were studied. The FAS consists of a linear motor, aerostatic bearings, high-resolution encoder and a motion controller. A control strategy consists of a proportional, integral and derivative (PID) feedback controller and velocity/acceleration feedforward controller is implemented to accommodate the system control performance. Experimental tests have been carried out to verify the performance of the FAS system.

  11. Servo simulation and modeling for the Gemini 8-m telescopes

    NASA Astrophysics Data System (ADS)

    Burns, Michael K.

    1995-06-01

    The Gemini servo simulation is a 6 degree of freedom (6-DOF) time domain simulation which is meant to represent the interaction between the servo controls and the telescope structure. The performance measure is root mean square image motion, based on the translations and rotations of the optical elements. The telescope structural model is based upon a sophisticated finite element analysis (FEA) to include the expected bending and torsional modes. Active control of the secondary mirror is modeled in a realistic way, including delays and noise, in order to show the expected improvement to image smear. Among the error sources for the altitude and azimuth control loops are angular encoder quantization, nonlinear bearing friction, motor D/A quantization, motor torque cogging, drive eccentricity, and tachometer ripple. Other relevant nonlinearities include drive amplifier voltage and current limits. Some other smaller simulations are also included: a simplified model for the tip-tilt response to telescope windshake, a model for azimuth drive slip-suppression, and a simple image-quality simulation.

  12. Performance verification and system parameter identification of spacecraft tape recorder control servo

    NASA Technical Reports Server (NTRS)

    Mukhopadhyay, A. K.

    1979-01-01

    Design adequacy of the lead-lag compensator of the frequency loop, accuracy checking of the analytical expression for the electrical motor transfer function, and performance evaluation of the speed control servo of the digital tape recorder used on-board the 1976 Viking Mars Orbiters and Voyager 1977 Jupiter-Saturn flyby spacecraft are analyzed. The transfer functions of the most important parts of a simplified frequency loop used for test simulation are described and ten simulation cases are reported. The first four of these cases illustrate the method of selecting the most suitable transfer function for the hysteresis synchronous motor, while the rest verify and determine the servo performance parameters and alternative servo compensation schemes. It is concluded that the linear methods provide a starting point for the final verification/refinement of servo design by nonlinear time response simulation and that the variation of the parameters of the static/dynamic Coulomb friction is as expected in a long-life space mission environment.

  13. Strong stabilization servo controller with optimization of performance criteria.

    PubMed

    Sarjaš, Andrej; Svečko, Rajko; Chowdhury, Amor

    2011-07-01

    Synthesis of a simple robust controller with a pole placement technique and a H(∞) metrics is the method used for control of a servo mechanism with BLDC and BDC electric motors. The method includes solving a polynomial equation on the basis of the chosen characteristic polynomial using the Manabe standard polynomial form and parametric solutions. Parametric solutions are introduced directly into the structure of the servo controller. On the basis of the chosen parametric solutions the robustness of a closed-loop system is assessed through uncertainty models and assessment of the norm ‖•‖(∞). The design procedure and the optimization are performed with a genetic algorithm differential evolution - DE. The DE optimization method determines a suboptimal solution throughout the optimization on the basis of a spectrally square polynomial and Šiljak's absolute stability test. The stability of the designed controller during the optimization is being checked with Lipatov's stability condition. Both utilized approaches: Šiljak's test and Lipatov's condition, check the robustness and stability characteristics on the basis of the polynomial's coefficients, and are very convenient for automated design of closed-loop control and for application in optimization algorithms such as DE. PMID:21501837

  14. 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.

  15. CAD-driven microassembly and visual servoing

    SciTech Connect

    Feddema, J.T.; Simon, R.W.

    1998-03-10

    This paper describes current research and development on a robotic visual servoing system for assembly of LIGA (Lithography Galvonoforming Abforming) parts. The workcell consists of an AMTI robot, precision stage, long working distance microscope, and LIGA fabricated tweezers for picking up the parts. Fourier optics methods are used to generate synthetic microscope images from CAD drawings. These synthetic images are used off-line to test image processing routines under varying magnifications and depths of field, They also provide reference image features which are used to visually servo the part to the desired position.

  16. Quick-response servo amplifies small hydraulic pressure differences

    NASA Technical Reports Server (NTRS)

    Wiegard, D. E.

    1966-01-01

    Hydraulic servo, which quickly diverts fluid to either of two actuators, controls the flow rates and pressures within a hydraulic system so that the output force of the servo system is independent of the velocity of the mechanism which the system actuates. This servo is a dynamic feedback control device.

  17. Phase-locked servo system. [for synchronizing the rotation of slip ring assembly

    NASA Technical Reports Server (NTRS)

    Burdin, C. (Inventor)

    1974-01-01

    A phase lock servo system is described for synchronizing the rotation of a slip ring assembly with the rotation of an air bearing table so that a minimum of torque will be imparted through cables extending from the slip ring assembly to the air bearing table as such is rotated. The system includes two servo loops. The first servo loop includes a rate gyroscope carried on the air bearing table which generates a signal through a summing junction to be compared with a signal coming from a tachometer coupled to the slip ring assembly. The corrective signal is applied to a torque motor for rotating the slip ring assembly. The second servo loop includes a pair of photo detector cells which generate pulses responsive to the rotation of the air bearing table and slip ring assembly which are fed through a phase detector, and a variable gain amplifier to the summing junction circuit to provide a fine adjustment for rotating the slip ring assembly.

  18. ELECTRICAL AND ELECTRONIC INDUSTRIAL CONTROL. A-C CONVENTIONAL MAGNETIC MOTOR CONTROL, PART I, UNIT 5, ASSIGNMENTS.

    ERIC Educational Resources Information Center

    SUTTON, MACK C.

    THIS GUIDE IS FOR INDIVIDUAL STUDENT USE IN STUDYING ALTERNATING CURRENT CONVENTIONAL MAGNETIC MOTOR CONTROL IN ELECTRICAL-ELECTRONIC PROGRAMS. IT WAS DEVELOPED BY AN INSTRUCTIONAL MATERIALS SPECIALIST AND ADVISERS. EACH OF THE 10 ASSIGNMENT SHEETS PROVIDES THE LESSON SUBJECT, PURPOSE, INTRODUCTORY INFORMATION, STUDY REFERENCES, SUPPLEMENTARY…

  19. ELECTRICAL AND ELECTRONIC INDUSTRIAL CONTROL. A-C CONVENTIONAL MAGNETIC MOTOR CONTROL, PART I, UNIT 5, INSTRUCTOR'S GUIDE.

    ERIC Educational Resources Information Center

    SUTTON, MACK C.

    THIS GUIDE IS FOR TEACHER USE IN DIRECTING INDIVIDUAL STUDY OF ALTERNATING CURRENT CONVENTIONAL MAGNETIC MOTOR CONTROL IN ELECTRICAL-ELECTRONIC PROGRAMS. IT WAS DEVELOPED BY AN INSTRUCTIONAL MATERIALS SPECIALIST AND ADVISERS. EACH OF THE 10 INSTRUCTOR'S SHEETS GIVES THE LESSON SUBJECT, PURPOSE, INTRODUCTORY INFORMATION, REFERENCES, AND…

  20. ELECTRICAL AND ELECTRONIC INDUSTRIAL CONTROL. A-C CONVENTIONAL MAGNETIC MOTOR CONTROL, PART II, UNIT 6, INSTRUCTOR'S GUIDE.

    ERIC Educational Resources Information Center

    SUTTON, MACK C.

    THIS GUIDE IS FOR TEACHER USE IN DIRECTING INDIVIDUAL STUDY OF ALTERNATING CURRENT CONVENTIONAL MAGNETIC MOTOR CONTROL IN ELECTRICAL-ELECTRONIC PROGRAMS. IT WAS DEVELOPED BY AN INSTRUCTIONAL MATERIALS SPECIALIST AND ADVISERS. EACH OF THE 10 INSTRUCTOR'S SHEETS GIVES THE LESSON SUBJECT, PURPOSE, INTRODUCTORY INFORMATION, REFERENCES, SUPPLEMENTARY…

  1. ELECTRICAL AND ELECTRONIC INDUSTRIAL CONTROL. A-C CONVENTIONAL MAGNETIC MOTOR CONTROL, PART II, UNIT 6, ASSIGNMENTS.

    ERIC Educational Resources Information Center

    SUTTON, MACK C.

    THIS STUDY GUIDE IS FOR INDIVIDUAL STUDENT USE IN STUDYING ALTERNATING CURRENT CONVENTIONAL MAGNETIC MOTOR CONTROL IN ELECTRICAL-ELECTRONIC PROGRAMS. IT WAS DEVELOPED BY AN INSTRUCTIONAL MATERIALS SPECIALIST AND ADVISERS. EACH OF THE 10 ASSIGNMENT SHEETS PROVIDES THE LESSON SUBJECT, PURPOSE, INTRODUCTORY INFORMATION, STUDY REFERENCES,…

  2. Compact, Lightweight Servo-Controllable Brakes

    NASA Technical Reports Server (NTRS)

    Lovchik, Christopher S.; Townsend, William; Guertin, Jeffrey; Matsuoka, Yoky

    2010-01-01

    Compact, lightweight servo-controllable brakes capable of high torques are being developed for incorporation into robot joints. A brake of this type is based partly on the capstan effect of tension elements. In a brake of the type under development, a controllable intermediate state of torque is reached through on/off switching at a high frequency.

  3. Differential spot-size focus servo

    NASA Technical Reports Server (NTRS)

    Milster, T. D.; Wang, M. S.; Froehlich, F. F.; Kann, J. L.; Treptau, J. P.; Erwin, K. E.

    1991-01-01

    We describe performance of a differential spot-size (wax-wane) focus servo. Crosstalk from the tracks are analyzed in the single detector and differential focus circuits. Magnitude of the crosstalk is reduced by a factor of three in the differential circuit. A false focus-error signal (FES) is present when the spot crosses sector marks at an angle.

  4. Reduction of Common-Mode Conducted Noise Emissions in PWM Inverter-fed AC Motor Drive Systems using Optimized Passive EMI Filter

    NASA Astrophysics Data System (ADS)

    Jettanasen, C.; Ngaopitakkul, A.

    2010-10-01

    Conducted electromagnetic interference (EMI) generated by PWM inverter-fed induction motor drive systems, which are currently widely used in many industrial and/or avionic applications, causes severe parasitic current problems, especially at high frequencies (HF). These restrict power electronic drive's evolution. In order to reduce or minimize these EMI problems, several techniques can be applied. In this paper, insertion of an optimized passive EMI filter is proposed. This filter is optimized by taking into account real impedances of each part of a considered AC motor drive system contrarily to commercial EMI filters designed by considering internal impedance of disturbance source and load, equal to 50Ω. Employing the latter EMI filter would make EMI minimization less effective. The proposed EMI filter optimization is mainly dedicated to minimize common mode (CM) currents due to its most dominant effects in this kind of system. The efficiency of the proposed optimization method using two-port network approach is deduced by comparing the minimized CM current spectra to an applied normative level (ex. DO-160D in aeronautics).

  5. High precision tracking control of a servo gantry with dynamic friction compensation.

    PubMed

    Zhang, Yangming; Yan, Peng; Zhang, Zhen

    2016-05-01

    This paper is concerned with the tracking control problem of a voice coil motor (VCM) actuated servo gantry system. By utilizing an adaptive control technique combined with a sliding mode approach, an adaptive sliding mode control (ASMC) law with friction compensation scheme is proposed in presence of both frictions and external disturbances. Based on the LuGre dynamic friction model, a dual-observer structure is used to estimate the unmeasurable friction state, and an adaptive control law is synthesized to effectively handle the unknown friction model parameters as well as the bound of the disturbances. Moreover, the proposed control law is also implemented on a VCM servo gantry system for motion tracking. Simulations and experimental results demonstrate good tracking performance, which outperform traditional control approaches. PMID:26928515

  6. Rotary fast tool servo system and methods

    DOEpatents

    Montesanti, Richard C.; Trumper, David L.

    2007-10-02

    A high bandwidth rotary fast tool servo provides tool motion in a direction nominally parallel to the surface-normal of a workpiece at the point of contact between the cutting tool and workpiece. Three or more flexure blades having all ends fixed are used to form an axis of rotation for a swing arm that carries a cutting tool at a set radius from the axis of rotation. An actuator rotates a swing arm assembly such that a cutting tool is moved in and away from the lathe-mounted, rotating workpiece in a rapid and controlled manner in order to machine the workpiece. A pair of position sensors provides rotation and position information for a swing arm to a control system. A control system commands and coordinates motion of the fast tool servo with the motion of a spindle, rotating table, cross-feed slide, and in-feed slide of a precision lathe.

  7. Visual servoing using statistical pressure snakes.

    SciTech Connect

    Schaub, Hanspeter

    2004-05-01

    A nonlinear visual servoing steering law is presented which is used to align a camera view with a visual target. A full color version of statistical pressure snakes is used to identify and track the target with a series of video frames. The nonlinear steering law provides camera-frame centric speed commands to a velocity based servo sub-system. To avoid saturating the subsystem, the commanded speeds are smoothly limited to remain within a finite range. Analytical error analysis is also provided illustrating how the two control gains contribute to the stiffness of the control. The algorithm is demonstrated on a pan and tilt camera system. The control law is able to smoothly realign the camera to point at the target.

  8. Dual arm master controller for a bilateral servo-manipulator

    DOEpatents

    Kuban, Daniel P.; Perkins, Gerald S.

    1989-01-01

    A master controller for a mechanically dissimilar bilateral slave servo-manipulator is disclosed. The master controller includes a plurality of drive trains comprising a plurality of sheave arrangements and cables for controlling upper and lower degrees of master movement. The cables and sheaves of the master controller are arranged to effect kinematic duplication of the slave servo-manipulator, despite mechanical differences therebetween. A method for kinematically matching a master controller to a slave servo-manipulator is also disclosed.

  9. Concept for sleeve induction motor with 1-msec mechanical time constant

    NASA Technical Reports Server (NTRS)

    Wiegand, D. E.

    1968-01-01

    Conductive sleeve induction motor having a 1-msec mechanical time constant is used with solid-state devices to control all-electric servo power systems. The servomotor rotor inertia is small compared to the maximum force rating of the servo motion, permitting high no-load acceleration.

  10. Development of an EtherCAT enabled digital servo controller for the Green Bank Telescope

    NASA Astrophysics Data System (ADS)

    Whiteis, Peter G.; Mello, Melinda J.

    2012-09-01

    EtherCAT (Ethernet for Control Automation Technology) is gaining wide spread popularity in the automation industry as a real time field bus based on low cost, Ethernet hardware. EtherCAT maximizes use of 100Mbps Ethernet hardware by using a collision free ring topology, efficient Ethernet frame utilization (> 95%), and data exchange "on the fly". These characteristics enable EtherCAT to achieve Master to Slave node data exchange rates of > 1000 Hz. The Green Bank Telescope, commissioned in 2000, utilizes an analog control system for motion control of 8 elevation and 16 azimuth motors. This architecture, while sufficient for observations at frequencies up to 50GHz, has significant limitations for the current scientific goals of observing at 115GHz. Accordingly, the Green Bank staff has embarked on a servo upgrade project to develop a digital servo system which accommodates development and implementation of advanced control algorithms. This paper describes how the new control system requirements, use of existing infrastructure and budget constraints led us to define a distributed motion control architecture where EtherCAT real-time Ethernet was selected as the communication bus. Finally, design details are provided that describe how NRAO developed a custom EtherCAT-enabled motor controller interface for the GBT's legacy motor drives in order to provide technical benefits and flexibility not available in commercial products.

  11. Powered orthosis and attachable power-assist device with Hydraulic Bilateral Servo System.

    PubMed

    Ohnishi, Kengo; Saito, Yukio; Oshima, Toru; Higashihara, Takanori

    2013-01-01

    This paper discusses the developments and control strategies of exoskeleton-type robot systems for the application of an upper limb powered orthosis and an attachable power-assist device for care-givers. Hydraulic Bilateral Servo System, which consist of a computer controlled motor, parallel connected hydraulic actuators, position sensors, and pressure sensors, are installed in the system to derive the joint motion of the exoskeleton arm. The types of hydraulic component structure and the control strategy are discussed in relation to the design philosophy and target joints motions. PMID:24110321

  12. Dynamic modeling and experiment of a new type of parallel servo press considering gravity counterbalance

    NASA Astrophysics Data System (ADS)

    He, Jun; Gao, Feng; Bai, Yongjun; Wu, Shengfu

    2013-11-01

    The large capacity servo press is traditionally realized by means of redundant actuation, however there exist the over-constraint problem and interference among actuators, which increases the control difficulty and the product cost. A new type of press mechanism with parallel topology is presented to develop the mechanical servo press with high stamping capacity. The dynamic model considering gravity counterbalance is proposed based on the virtual work principle, and then the effect of counterbalance cylinder on the dynamic performance of the servo press is studied. It is found that the motor torque required to operate the press is a lot less than the others when the ratio of the counterbalance force to the gravity of ram is in the vicinity of 1.0. The stamping force of the real press prototype can reach up to 25 MN on the position of 13 mm away from the bottom dead center. The typical deep-drawing process with 1 200 mm stroke at 8 strokes per minute is proposed by means of five order polynomial. On this process condition, the driving torques are calculated based on the above dynamic model and the torque measuring test is also carried out on the prototype. It is shown that the curve trend of calculation torque is consistent to the measured result and that the average error is less than 15%. The parallel mechanism is introduced into the development of large capacity servo press to avoid the over-constraint and interference of traditional redundant actuation, and its dynamic characteristics with gravity counterbalance are presented.

  13. Hydraulic servo mechanism of automatic transmission for vehicle

    SciTech Connect

    Sumiya, K.; Sakaguchi, Y.; Taga, Y.; Kubo, S.; Moroto, S.

    1988-06-07

    In a vehicle having an automatic transmission, a hydraulic servo control mechanism is described comprising: a hydraulic pressure source, a hydraulic servo; an accumulator; a drain oil line; interconnecting passage means providing a fluid path from the hydraulic pressure source to the hydraulic servo and from the hydraulic servo to the drain oil line; a selector valve, connected in the interconnecting passage means, for alternately connecting the hydraulic servo to the hydraulic pressure source and to the drain oil line; branch passage means connecting the accumulator to a portion of the interconnecting passage extending from the selector valve to the servo, the branch passage means meeting the portion of the interconnecting passage at a junction; first throttle means (R/sub 10/) in the branch passage means to connect the accumulator to the hydraulic servo; check valve means (q/sub 1/) in the branch passage means, and in parallel with the first throttle means, to connect the hydraulic servo to the accumulator; second throttle means (R/sub 20/), in the interconnecting passage means between the junction and the oil drain line; and relief valve means (V/sub r/), in the interconnecting passage means between the junction and the oil drain line, for adjusting the working oil discharge rate.

  14. Controller parameter tuning of delta robot based on servo identification

    NASA Astrophysics Data System (ADS)

    Zhao, Qing; Wang, Panfeng; Mei, Jiangping

    2015-03-01

    High-speed pick-and-place parallel robot is a system where the inertia imposed on the motor shafts is real-time changing with the system configurations. High quality of computer control with proper controller parameters is conducive to overcoming this problem and has a significant effect on reducing the robot's tracking error. By taking Delta robot as an example, a method for parameter tuning of the fixed gain motion controller is presented. Having identifying the parameters of the servo system in the frequency domain by the sinusoidal excitation, the PD+feedforward control strategy is proposed to adapt to the varying inertia loads, allowing the controller parameters to be tuned by minimizing the mean square tracking error along a typical trajectory. A set of optimum parameters is obtained through computer simulations and the effectiveness of the proposed approach is validated by experiments on a real prototype machine. Let the traveling plate undergoes a specific trajectory and the results show that the tracking error can be reduced by at least 50% in comparison with the conventional auto-tuning and Z-N methods. The proposed approach is a whole workspace optimization and can be applied to the parameter tuning of fixed gain motion controllers.

  15. Motor Controllers

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Kollmorgen Corporation's Mermaid II two person submersible is propeller-driven by a system of five DC brushless motors with new electronic controllers that originated in work performed in a NASA/DOE project managed by Lewis Research Center. A key feature of the system is electric commutation rather than mechanical commutation for converting AC current to DC.

  16. Highly accurate servo control of reference beam angle in holographic memory with polarized servo beam

    NASA Astrophysics Data System (ADS)

    Hosaka, Makoto; Ogata, Takeshi; Yamada, Kenichiro; Yamazaki, Kazuyoshi; Shimada, Kenichi

    2016-09-01

    We propose a new servo technique for controlling the reference beam angle in angular multiplexing holographic memory to attain higher capacity and higher speed data archiving. An orthogonally polarized beam with an incident angle slightly different from that of the reference beam is newly applied to the optics. The control signal for the servo is generated as the difference between the diffracted light intensities of these two beams from a hologram. The incident angle difference between the beams to the medium was optimized as sufficient properties of the control signal were obtained. The high accuracy of the control signal with an angle error lower than 1.5 mdeg was successfully confirmed in the simulations and experiments.

  17. Motor technology for mining applications advances

    SciTech Connect

    Fiscor, S.

    2009-08-15

    AC motors are steadily replacing DC motors in mining and mineral processing equipment, requiring less maintenance. The permanent magnet rotor, or the synchronous motor, has enabled Blador to introduce a line of cooling tower motors. Synchronous motors are soon likely to take over from the induction motor. 1 photo.

  18. Electric motor model repair specifications

    SciTech Connect

    1995-08-01

    These model repair specifications list the minimum requirements for repair and overhaul of polyphase AC squireel cage induction motors. All power ranges, voltages, and speeds of squirrel cage motors are covered.

  19. Servo-controlled intravital microscope system

    NASA Technical Reports Server (NTRS)

    Mansour, M. N.; Wayland, H. J.; Chapman, C. P. (Inventor)

    1975-01-01

    A microscope system is described for viewing an area of a living body tissue that is rapidly moving, by maintaining the same area in the field-of-view and in focus. A focus sensing portion of the system includes two video cameras at which the viewed image is projected, one camera being slightly in front of the image plane and the other slightly behind it. A focus sensing circuit for each camera differentiates certain high frequency components of the video signal and then detects them and passes them through a low pass filter, to provide dc focus signal whose magnitudes represent the degree of focus. An error signal equal to the difference between the focus signals, drives a servo that moves the microscope objective so that an in-focus view is delivered to an image viewing/recording camera.

  20. Tilt Servo Control by Intelligent Algorithm in Holographic Data Storage System

    NASA Astrophysics Data System (ADS)

    Kim, Jang Hyun; Jeong, Wooyoung; Yang, Hyunseok

    2013-09-01

    Tracking servo and tilt servo control are very important research in holographic data storage system. In this paper, we propose intelligent servo control by fuzzy rules in holographic data storage system. Hence, we have found pattern of tilt servo control in holographic data storage system through fuzzy system. Fuzzy rules were generated by subtractive clustering algorithm for controlling tilt servo. Therefore, we control tilt servo using fuzzy rules in holographic data storage system. Consequently, practical pattern of tilt servo control was found by intelligence algorithm in holographic data storage system.

  1. Dual arm master controller for a bilateral servo-manipulator

    SciTech Connect

    Kuban, D.P.; Perkins, G.S.

    1989-11-28

    A master controller for a mechanically dissimilar bilateral slave servo-manipulator is disclosed. The master controller includes a plurality of drive trains comprising a plurality of sheave arrangements and cables for controlling upper and lower degrees of master movement. The cables and sheaves of the master controller are arranged to effect kinematic duplication of the slave servo-manipulator, despite mechanical differences there between. A method for kinematically matching a master controller to a slave servo-manipulator is also disclosed. 13 figs.

  2. The research on property of servo-control and drive system for 1.2 m Alt-Az telescope. The function of servo system compensation network in control system (2)

    NASA Astrophysics Data System (ADS)

    Li, Zhu-Lian; Xiong, Yao-Heng

    2005-06-01

    According to the requirement of SLR (Satellite Laser Range) using 1.2 m Alt-Az telescope of Yunnan Observatory, and the analysis of function of cascade compensation network in control system and the observation results, the compensation network of servo system of 1.2 m Alt-Az telescope, and the performance of control system after its compensation are discussed in this article. When friction drive is fulfilled by two torque motors, and PD compensation network in servo control system is used, it is found that the capability of rapid tracking of the 1.2 m telescope is actually improved, and the telescope can achieve 10°/s2 of maximum azimuth angle acceleration, 5°/s of maximum azimuth angle velocity, and it can meet the demand of tracking satellites near the Earth.

  3. Hydraulic servo system increases accuracy in fatigue testing

    NASA Technical Reports Server (NTRS)

    Dixon, G. V.; Kibler, K. S.

    1967-01-01

    Hydraulic servo system increases accuracy in applying fatigue loading to a specimen under test. An error sensing electronic control loop, coupled to the hydraulic proportional closed loop cyclic force generator, provides an accurately controlled peak force to the specimen.

  4. Reliable Control Using Disturbance Observer and Equivalent Transfer Function for Position Servo System in Current Feedback Loop Failure

    NASA Astrophysics Data System (ADS)

    Ishikawa, Kaoru; Nakamura, Taro; Osumi, Hisashi

    A reliable control method is proposed for multiple loop control system. After a feedback loop failure, such as case of the sensor break down, the control system becomes unstable and has a big fluctuation even if it has a disturbance observer. To cope with this problem, the proposed method uses an equivalent transfer function (ETF) as active redundancy compensation after the loop failure. The ETF is designed so that it does not change the transfer function of the whole system before and after the loop failure. In this paper, the characteristic of reliable control system that uses an ETF and a disturbance observer is examined by the experiment that uses the DC servo motor for the current feedback loop failure in the position servo system.

  5. Fuzzy control of hydraulic servo system based on DSP

    NASA Astrophysics Data System (ADS)

    He, Juan; Yuan, Song-Yue

    2011-10-01

    On the basis of high-speed switching valve of hydraulic servo system, the complex mathematical model of nonlinear hydraulic servo system was analyzed and constructed. A intelligent Fuzzy control method using TMS320LF2407A DSP chip as primary processor was put forward. The simulation results show that the control strategy has a better effect than the conventional PID control has. And the non-differential control of the system has been basically achieved.

  6. Sub-millimeter servo system for sample positioning based on thresholding of defocused laser spot

    NASA Astrophysics Data System (ADS)

    Wang, Zheng; Cao, Liangcai; Zhang, Enyao; Jin, Guofan

    2013-12-01

    Accurate sample positioning and automatic sample operation can improve the performance of measuring instruments. A Sub-millimeter servo system for sample positioning based on thresholding of defocused laser spot is proposed. The effective laser spot image is extracted by thresholding of the light cone section on the sample surface. By estimating the section area and centroid of the spot, the defocus status and position of the measured sample can be acquired. A focused light cone at visible wavelength is cast onto the surface of sample, forming a marked laser spot as the indicator of the measurement point. A CCD camera is used for visual imaging, and a high-precision three-dimensional motorized translation stage is used for the accurate servo control. The marked spot is real-time monitored and processed in the platform of LabVIEW. The Autonomous Thresholding Image-Processing Algorithm (ATIPA) is proposed to detect and analyze the defocused marked spot, through which system creates a servo whereby accurate position control of the sample can be achieved. The measurement point on the sample can be accurately located by computing the center coordinates of the marked spot. And a focus function is implemented by measuring the size of defocused spot. This focus function is then used within an improved climbing search algorithm to obtain the focused sample position via moving the sample stage. Experimental results show that the system could measure the laser spot and control the sample in a robust, repeatable way within reasonable errors. The accuracy of the sample autofocus reaches 0.1 mm.

  7. Method for On-line Estimation of Electrical Motor Parameter Variation and Current Sensor Offset for SPM Motor

    NASA Astrophysics Data System (ADS)

    Uenaka, Yutaro; Sazawa, Masaki; Ohishi, Kiyoshi; Kenji, Takahashi

    The servo system of a permanent magnet (PM) motor should always maintain fine torque and fine speed responses. Accurate motor parameter identification is necessary for the PM motor servo system because the current control system is designed by considering the electric parameters of the PM motor. However, the motor parameters vary with the age of the motor and temperature. Moreover, current sensors have offset values. When the current sensor has offset values, the PM motor servo system produces torque ripple. In order to overcome these problems, this paper proposes a new real-time estimation method for both current sensor offsets and electrical parameters (resistance Ra, inductance La, and magnetic flux φfa) of the surface permanent magnet (SPM) motor. The proposed method involves the use of a real-time algorithm and a current simulator, which is operated using a DSP software system. In order to accurately estimate the motor parametera, the proposed method is using estimate currents, DC terms of sensor currents, and nominal motor parameter value. The experimental results of this study confirm that the proposed method satisfactorily estimates the current sensor offset of the U phase and V phase, as well as the electrical motor parametersRa, La, and φfa accurately.

  8. Fine-tuning motor torque

    SciTech Connect

    O`Connor, L.

    1996-01-01

    Direct-torque control, a new method of regulating the output of ac induction motors, provides a swift response to input commands. A new variable-speed ac motor drive system that responds to torque input commands 10 times faster than current state-of-the-art drives has been developed by ABB Industrial Systems Inc. in New Berlin, Wis. The new control system, called the ACS 600, provides an alternative to drive systems that use sophisticated flux vector control or more routine pulse width modulation--the primary methods of regulating the output of ac induction motors. The ACS 600 is suitable for use in single motor applications that require a standard level of performance, such as conveyors, fans, and pumps. But it will likely be more valuable in applications that require the linking of multiple motors, such as textile production, and in applications that require tight control over torque, such as cranes, elevators, and centrifuges.

  9. A Machine Tool Controller using Cascaded Servo Loops and Multiple Feedback Sensors per Axis

    SciTech Connect

    Weinert, G F; Hopkins, D J; Wulff, T A

    2004-03-19

    In the past, several of LLNL precision machine tools have been built with custom in-house designed machine tool controllers (CNC). In addition, many of these controllers have reached the end of their maintainable lifetime, limit future machine application enhancements, have poor operator interfaces and are a potential single point of failure for the machine tool. There have been attempts to replace some of these custom controllers with commercial controller products, unfortunately, this has occurred with only limited success. Many commercial machine tool controllers have the following undesirable characteristics, a closed architecture (use as the manufacturer intended and not as LLNL would desire), allow only a single feedback device per machine axis and have limited servo axis compensation calculations. Technological improvements in recent years have allowed for the development of some commercial machine tool controllers that are more open in their architecture and have the power to solve some of these limitations. In this paper, we exploit the capabilities of one of these controllers to allow it to process multiple feedback sensors for tool tip calculations in real time and to extend the servo compensation capabilities by cascading several standard motor compensation loops.

  10. A quasiphysics intelligent model for a long range fast tool servo.

    PubMed

    Liu, Qiang; Zhou, Xiaoqin; Lin, Jieqiong; Xu, Pengzi; Zhu, Zhiwei

    2013-01-01

    Accurately modeling the dynamic behaviors of fast tool servo (FTS) is one of the key issues in the ultraprecision positioning of the cutting tool. Herein, a quasiphysics intelligent model (QPIM) integrating a linear physics model (LPM) and a radial basis function (RBF) based neural model (NM) is developed to accurately describe the dynamic behaviors of a voice coil motor (VCM) actuated long range fast tool servo (LFTS). To identify the parameters of the LPM, a novel Opposition-based Self-adaptive Replacement Differential Evolution (OSaRDE) algorithm is proposed which has been proved to have a faster convergence mechanism without compromising with the quality of solution and outperform than similar evolution algorithms taken for consideration. The modeling errors of the LPM and the QPIM are investigated by experiments. The modeling error of the LPM presents an obvious trend component which is about ±1.15% of the full span range verifying the efficiency of the proposed OSaRDE algorithm for system identification. As for the QPIM, the trend component in the residual error of LPM can be well suppressed, and the error of the QPIM maintains noise level. All the results verify the efficiency and superiority of the proposed modeling and identification approaches. PMID:24163627

  11. 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.

  12. A Quasiphysics Intelligent Model for a Long Range Fast Tool Servo

    PubMed Central

    Liu, Qiang; Zhou, Xiaoqin; Lin, Jieqiong; Xu, Pengzi; Zhu, Zhiwei

    2013-01-01

    Accurately modeling the dynamic behaviors of fast tool servo (FTS) is one of the key issues in the ultraprecision positioning of the cutting tool. Herein, a quasiphysics intelligent model (QPIM) integrating a linear physics model (LPM) and a radial basis function (RBF) based neural model (NM) is developed to accurately describe the dynamic behaviors of a voice coil motor (VCM) actuated long range fast tool servo (LFTS). To identify the parameters of the LPM, a novel Opposition-based Self-adaptive Replacement Differential Evolution (OSaRDE) algorithm is proposed which has been proved to have a faster convergence mechanism without compromising with the quality of solution and outperform than similar evolution algorithms taken for consideration. The modeling errors of the LPM and the QPIM are investigated by experiments. The modeling error of the LPM presents an obvious trend component which is about ±1.15% of the full span range verifying the efficiency of the proposed OSaRDE algorithm for system identification. As for the QPIM, the trend component in the residual error of LPM can be well suppressed, and the error of the QPIM maintains noise level. All the results verify the efficiency and superiority of the proposed modeling and identification approaches. PMID:24163627

  13. Servo-controlled biaxial test system

    SciTech Connect

    Thayer, W.L.

    1983-02-11

    A large test program requiring axial torsion tests was submitted to the Materials Test and Evaluation Section of the Engineering Sciences Division by the Chemistry Department. The objective of these tests was to provide insight with regard to the fundamental aspects of plastic deformation and hardening of nickel. Thes tests will also provide the constants necessary for a constitutive equation for use in weld modeling. The weld models will attempt to predict residual stresses in nickel welds. The test program consisted of approximately 70 specimens of high purity nickel to be tested in torsion over a large temperature range (RT - 900/sup 0/C) at a strain rate of about 1 x 10/sup -4/ in./in./sec to steady state at each temperature. After having attained steady state, the strain-rate-reversal (Bauschinger test) and incremental-changes-in-strain-rate tests (10/sup -4/ to 2 x 10/sup -3/ in./in./sec) at constant structure will be conducted. Additional tests such as transient backstress and yield surface distortion (using multi-axial stress states) will be carried out. This particular request required a biaxial test machine capable of more than 360/sup 0/ rotation in torsion. Temperature capabilities, atmosphere control, and a control system were also needed whereby the machine could be operated in torsion using strain control. Such a machine did not commercially exist so it was necessary to build one. The basic unit chosen was a 20K Servo-Electric Hydraulic Test Machine to which we added a simple anti-rotation fixture for the ram. This constituted the axial portion of the system.

  14. Current Sensor Offset and Motor Parameter Variations Estimation Method for PM Motor by Using Current Simulator

    NASA Astrophysics Data System (ADS)

    Sazawa, Masaki; Senko, Tomohiro; Uenaka, Yutaro; Ohishi, Kiyoshi

    The servo system of a PM motor is required to have a fine torque response and fine speed response. The current controller of the PM motor should have a fine current response. However, when the current sensors of the U phase and V phase have offset values, the servo system of the PM motor shows a torque ripple and cannot accurately identify motor parameters such as the motor resistance Ra and motor inductance La. In order to overcome these problems, this paper proposes a new method for the fine estimation and automatic adjustment of current sensor offsets and the electrical parameters of the PM motor. The proposed method involves the use of a real-time algorithm and a current simulator, which is operated using a DSP software system. The experimental results of this study confirm that the proposed method satisfactorily estimates the offsets of the current of sensors of theU phase and V phase, Ra, and La accurately; the method also helps in the fine self-tuning of the current controller of the servo system.

  15. Servo control booster system for minimizing following error

    DOEpatents

    Wise, William L.

    1985-01-01

    A closed-loop feedback-controlled servo system is disclosed which reduces command-to-response error to the system's position feedback resolution least increment, .DELTA.S.sub.R, on a continuous real-time basis for all operating speeds. The servo system employs a second position feedback control loop on a by exception basis, when the command-to-response error .gtoreq..DELTA.S.sub.R, to produce precise position correction signals. When the command-to-response error is less than .DELTA.S.sub.R, control automatically reverts to conventional control means as the second position feedback control loop is disconnected, becoming transparent to conventional servo control means. By operating the second unique position feedback control loop used herein at the appropriate clocking rate, command-to-response error may be reduced to the position feedback resolution least increment. The present system may be utilized in combination with a tachometer loop for increased stability.

  16. Comprehensive parameter identification of feed servo systems with friction based on responses of the worktable

    NASA Astrophysics Data System (ADS)

    Liu, Lilan; Wu, Ziying

    2015-12-01

    A comprehensive identification method for structure and friction parameters of feed servo systems is put forward. A motor direct-connected feed system with Stribeck friction law is investigated. The relation between the critical stick-slip velocity of the worktable and the structure parameters as well as the difference between the static and Coulomb friction coefficient is derived first. Then, according to the data of critical stick-slip velocities at different feed positions, the structural parameters (such as diameter, lead and bearing length of the ball screw) are estimated using the nonlinear least square method. Furthermore, based on the stick-slip displacement response of the worktable, the Stribeck friction parameters are obtained using the direct graphical registration method. The feasibility and validity of the presented identification method is verified by numerical simulation. All the work can provide a theoretical reference for the comprehensive parameters identification of feed systems.

  17. Antenna servo design for tracking low-earth-orbiting satellites

    NASA Astrophysics Data System (ADS)

    Gawronski, W.; Mellstrom, J. A.

    1994-11-01

    The upcoming NASA missions will require tracking of low-orbit satellites. As a consequence, NASA antennas will be required to track satellites at higher rates than for the current deep-space missions. This paper investigates servo design issues for the 34-m beam-waveguide antennas that track low-orbit satellites. This includes upgrading the servo with a feedforward loop, monopulse controller design, and tracking error reduction either through proper choice of elevation pinion location or through application of a notch filter or adjustment of the elevation drive amplifier gain. Finally, improvement of the signal-to-noise ratio through averaging of the oversampled monopulse signal is described.

  18. Speed control for synchronous motors

    NASA Technical Reports Server (NTRS)

    Packard, H.; Schott, J.

    1981-01-01

    Feedback circuit controls fluctuations in speed of synchronous ac motor. Voltage proportional to phase angle is developed by phase detector, rectified, amplified, compared to threshold, and reapplied positively or negatively to motor excitation circuit. Speed control reduces wow and flutter of audio turntables and tape recorders, and enhances hunting in gyroscope motors.

  19. Electric vehicle motors and controllers

    NASA Technical Reports Server (NTRS)

    Secunde, R. R.

    1981-01-01

    Improved and advanced components being developed include electronically commutated permanent magnet motors of both drum and disk configuration, an unconventional brush commutated motor, and ac induction motors and various controllers. Test results on developmental motors, controllers, and combinations thereof indicate that efficiencies of 90% and higher for individual components, and 80% to 90% for motor/controller combinations can be obtained at rated power. The simplicity of the developmental motors and the potential for ultimately low cost electronics indicate that one or more of these approaches to electric vehicle propulsion may eventually displace presently used controllers and brush commutated dc motors.

  20. Support for transmission shaft and hydraulic servo drum

    SciTech Connect

    Kobayashi, K.; Sumiya, K.; Taga, Y.; Watanabe, K.

    1987-09-15

    In a support for use in an automatic transmission apparatus of the type having a transmission shaft for transmitting power, an annular hydraulic servo drum and a piston fitted in the hydraulic servo drum for engaging and disengaging a friction engaging means is described, wherein the support has an axially extending tubular supporting portion having an inner peripheral surface for supporting the transmission shaft, an outer peripheral surface for supporting an inner cylindrical portion of the hydraulic servo drum, and working oil passages formed and adapted for supplying and discharging a working oil to and from the hydraulic servo drum. The improvement consists of: a support body made of light material having a first radially extending oil passage leading from an oil pressure controller for supplying and discharging a working oil and communicating with the inner peripheral surface of the tubular supporting portion; an inner sleeve of a heavier material than the support body fitting on the inner peripheral surface of the tubular supporting portion to cover the inner axially extending oil groove thereby forming an oil passage for working oil; and an outer sleeve of a heavier material than the support body fitting on the outer peripheral surface of the tubular supporting portion.

  1. Visual servoing of robot manipulators -- Part 1: Projective kinematics

    SciTech Connect

    Ruf, A.; Horaud, R.

    1999-11-01

    Visual servoing of robot manipulators is a key technique where the appearance of an object in the image plane is used to control the velocity of the end-effector such that the desired position is reached in the scene. The vast majority of visual servoing methods proposed so far uses calibrated robots in conjunction with calibrated cameras. It has been shown that the behavior of visual control loops does not degrade too much in the presence of calibration errors. Nevertheless, camera and robot calibration are complex and time-consuming processes requiring special-purpose mechanical devices, such as theodolites and calibration jigs. In this paper, the authors, suggest formulating a visual servoing control loop in nonmetric space, which in this case amounts to the projective space in which a triangulation of the scene using an uncalibrated stereo rig is expressed. The major consequence of controlling the robot in nonmetric space rather than in Euclidean space is that both the robot's direct kinematic map and the robot's Jacobian matrix must be defined in this space as well. Finally, they provide a practical method to estimate the projective kinematic model and they describe some preliminary simulated experiments that use this nonmetric model to perform stereo-based servoing. Nevertheless, in-depth analysis of projective control will be the topic of a forthcoming paper.

  2. System and method for motor speed estimation of an electric motor

    DOEpatents

    Lu, Bin; Yan, Ting; Luebke, Charles John; Sharma, Santosh Kumar

    2012-06-19

    A system and method for a motor management system includes a computer readable storage medium and a processing unit. The processing unit configured to determine a voltage value of a voltage input to an alternating current (AC) motor, determine a frequency value of at least one of a voltage input and a current input to the AC motor, determine a load value from the AC motor, and access a set of motor nameplate data, where the set of motor nameplate data includes a rated power, a rated speed, a rated frequency, and a rated voltage of the AC motor. The processing unit is also configured to estimate a motor speed based on the voltage value, the frequency value, the load value, and the set of nameplate data and also store the motor speed on the computer readable storage medium.

  3. Frequency modulation drive for a piezoelectric motor

    DOEpatents

    Mittas, Anthony

    2001-01-01

    A piezoelectric motor has peak performance at a specific frequency f.sub.1 that may vary over a range of frequencies. A drive system is disclosed for operating such a motor at peak performance without feedback. The drive system consists of the motor and an ac source connected to power the motor, the ac source repeatedly generating a frequency over a range from f.sub.1 -.DELTA.x to f.sub.1 +.DELTA.y.

  4. Research on inverter test system of synchronous motor using modbus communication

    NASA Astrophysics Data System (ADS)

    Cao, Wenlun; Chen, Bei; He, Yuyao

    2013-03-01

    In this paper, the hardware architecture of the servo system composed by self-made inverter and permanent magnet synchronous motor is introduced as well as its measurement and control system software features. Basing on the Modbus-RTU protocols which contain the CRC data verification between IPC and the inverter, we have built a communication system. The measurement and control software of servo system are realized, which consists of self-made inverter and PMSM. Compared with the servo system which consists of Schindler's ATV31 inverter and SIMO's asynchronous motor, the results are given. The experiment parameters include harmonic content which is contained by phase current and voltage, and also the motor speed. The results show that the measurement and control system are stable and reliable. Both the harmonic content of the Inverter output and the motor speed meet the requirements.

  5. Control system for an induction motor with energy recovery

    NASA Technical Reports Server (NTRS)

    Nola, F. J. (Inventor)

    1983-01-01

    A control circuit for an induction motor powered system is disclosed in which a power factor controlled servo loop is used to control, via the phase angle of firing of a triac, the power input to the motor, as a function of load placed on the motor by machinery of the powered system. Then, upon application of torque by this machinery to the motor, which tends to overspeed the motor, the firing angle of the triac is automatically set to a fixed, and relatively short, firing angle.

  6. Mathematical modeling of bent-axis hydraulic piston motors

    NASA Technical Reports Server (NTRS)

    Bartos, R. D.

    1992-01-01

    Each of the DSN 70-m antennas uses 16 bent-axis hydraulic piston motors as part of the antenna drive system. On each of the two antenna axes, four motors are used to drive the antenna and four motors provide counter torque to remove the backlash in the antenna drive train. This article presents a mathematical model for bent-axis hydraulic piston motors. The model was developed to understand the influence of the hydraulic motors on the performance of the DSN 70-m antennas' servo control system.

  7. Motor degradation prediction methods

    SciTech Connect

    Arnold, J.R.; Kelly, J.F.; Delzingaro, M.J.

    1996-12-01

    Motor Operated Valve (MOV) squirrel cage AC motor rotors are susceptible to degradation under certain conditions. Premature failure can result due to high humidity/temperature environments, high running load conditions, extended periods at locked rotor conditions (i.e. > 15 seconds) or exceeding the motor`s duty cycle by frequent starts or multiple valve stroking. Exposure to high heat and moisture due to packing leaks, pressure seal ring leakage or other causes can significantly accelerate the degradation. ComEd and Liberty Technologies have worked together to provide and validate a non-intrusive method using motor power diagnostics to evaluate MOV rotor condition and predict failure. These techniques have provided a quick, low radiation dose method to evaluate inaccessible motors, identify degradation and allow scheduled replacement of motors prior to catastrophic failures.

  8. A six-degree-of-freedom magnetic levitation fine stage for a high-precision and high-acceleration dual-servo stage

    NASA Astrophysics Data System (ADS)

    Kim, MyeongHyeon; Jeong, Jae-heon; Kim, HyoYoung; Gweon, DaeGab

    2015-10-01

    This paper presents a novel six-degree-of-freedom magnetic levitation fine stage for a dual-servo stage. The proposed fine stage is levitated and actuated, using a voice coil motor actuator with a Halbach magnet array. For a dual-servo stage, fine stage performance is deeply intertwined with coarse stage performance. Because the fine stage is installed over the coarse stage, the overall size of the fine stage can be limited by the moving plate of the coarse stage. Therefore, magnetic flux modeling and optimization are performed to manufacture optimal fine stages. To control the fine stage, actuator kinetics and sensor kinematics are proposed. Homing control is implemented by using linear variable differential transformers, whereas fine control is implemented by capacitance sensors and laser interferometers. Finally, experimental results of in-position stability, moving range, and repeatability are presented.

  9. High Bandwidth Short Stroke Rotary Fast Tool Servo

    SciTech Connect

    Montesanti, R C; Trumper, D L

    2003-08-22

    This paper presents the design and performance of a new rotary fast tool servo (FTS) capable of developing the 40 g's tool tip acceleration required to follow a 5 micron PV sinusoidal surface at 2 kHz with a planned accuracy of 50 nm, and having a full stroke of 50 micron PV at lower frequencies. Tests with de-rated power supplies have demonstrated a closed-loop unity-gain bandwidth of 2 kHz with 20 g's tool acceleration, and we expect to achieve 40 g's with supplies providing {+-} 16 Amp to the Lorentz force actuator. The use of a fast tool servo with a diamond turning machine for producing non-axisymmetric or textured surfaces on a workpiece is well known. Our new rotary FTS was designed to specifically accommodate fabricating prescription textured surfaces on 5 mm diameter spherical target components for High Energy Density Physics experiments on the National Ignition Facility Laser (NIF).

  10. Hydraulic servo for friction coupling element of automatic transmission

    SciTech Connect

    Sumiya, K.; Kano, T.; Kubo, S.; Watanabe, K.

    1987-07-28

    A hydraulic servo is described for a friction coupling element in an automatic transmission including a casing, the hydraulic servo, comprising: an annular drum having a first cylinder, a second cylinder, and a side wall connecting the first and second cylinders all integrally formed together as a single piece by press forming, the first cylinder having splines on its outer cylindrical surface and fixed to the interior of the casing through the splines and the second cylinder having splines on its inner cylindrical surface; a press-formed third cylinder joined to the side wall of the annular drum by a fully encircling weld; a piston fitted between the first cylinder and the third cylinder; and biasing means provided between the third cylinder and the second cylinder for returning the piston.

  11. Inherent limitations of fixed time servo-controlled radiometric calorimetry

    SciTech Connect

    Wetzel, J.R.; Duff, M.F.; Lemming, J.F.

    1987-01-01

    There has been some interest in low precision, short run time calorimetry measurements. This type of calorimetry measurement has been proposed for use when high precision measurements are not required, for example, to screen scrap containers to determine if there is enough material to be measured more accurately of for confirmatory measurements that only require low precision results. The equipment needed to make these measurements is a servo-controlled calorimeter with a sample preequilibration bath. The preequilibration bath temperature is set to the internal temperature of the calorimeter running at a fixed servo-controlled wattage level. The sample power value is determined at a fixed time form the sample loading into the calorimeter. There are some limitations and areas of uncertainties in the use of data obtained by this method. Data collected under controlled conditions demonstrate the limitations. Sample packaging, preequilibration time, and item wattage were chosen as the variables most likely to be encountered in a plant environment.

  12. Visual Servoing for a Quadrotor UAV in Target Tracking Applications

    NASA Astrophysics Data System (ADS)

    Popova, Marinela Georgieva

    This research study investigates the design and implementation of position-based and image-based visual servoing techniques for controlling the motion of quadrotor unmanned aerial vehicles (UAVs). The primary applications considered are tracking stationary and moving targets. A novel position-based tracking law is developed and integrated with inner loop proportional-integral-derivative control algorithm. A theoretical proof for the stability of the proposed method is provided and numerical simulations are performed to validate the performance of the closed-loop system. A classical image-based visual servoing technique is also implemented and a modification of the classical method is suggested to reduce the undesirable effects due to the underactuated quadrotor system. Finally, the case when the quadrotor loses sight of the target is investigated and several solutions are proposed to help maintain the view of the target.

  13. Servo-amplifiers for ion current measurement in mass spectrometry

    USGS Publications Warehouse

    Stacey, J.S.; Russell, R.D.; Kollar, F.

    1965-01-01

    A servo-voltmeter can provide a useful alternative to the d.c. amplifier or vibrating reed electrometer for the accurate measurement of mass spectrometer ion currents, and has some advantages which recommend its use in certain applications. A generalized analysis based on servomechanism theory is presented as an aid for understanding the design criteria for this type of device. Two existing systems are described and their operation and performance are examined.

  14. Servo Controlled Variable Pressure Modification to Space Shuttle Hydraulic Pump

    NASA Technical Reports Server (NTRS)

    Kouns, H. H.

    1983-01-01

    Engineering drawings show modifications made to the constant pressure control of the model AP27V-7 hydraulic pump to an electrically controlled variable pressure setting compensator. A hanger position indicator was included for continuously monitoring hanger angle. A simplex servo driver was furnished for controlling the pressure setting servovalve. Calibration of the rotary variable displacement transducer is described as well as pump performance and response characteristics.

  15. Research on Image-Based Fuzzy Visual Servo Forpicking Robot

    NASA Astrophysics Data System (ADS)

    Jian, Song

    An open eggplant picking robot experiment system is developed successfully which includes a arthral manipulator with 4 DOF, a motion controller, a color image processing card, a camera and a PC. The fixed bilateral threshold based histogram is adopted to segment the G-B gray images of eggplant in the growth environment.. To meet the vision requirement of the eggplant picking robot, the object's characters, such as outline, area, center of gravity, enclosing rectangle and the point to cut off, are extracted. We applied fuzzy control to the visual servo of picking robot and selected the fruit image's centre of gravity coordinate as variable for the fuzzy control system to create a fuzzy controller. The output control was modified by the self-adjustment factor and thus a fuzzy control diagram for the precise output control was obtained. The results show that the image-based picking robot fuzzy visual servo control overcomes time variation, nonlinearity and strong coupling of the robot visual servo control and has high response speed and good robustness.

  16. Adaptive backstepping slide mode control of pneumatic position servo system

    NASA Astrophysics Data System (ADS)

    Ren, Haipeng; Fan, Juntao

    2016-06-01

    With the price decreasing of the pneumatic proportional valve and the high performance micro controller, the simple structure and high tracking performance pneumatic servo system demonstrates more application potential in many fields. However, most existing control methods with high tracking performance need to know the model information and to use pressure sensor. This limits the application of the pneumatic servo system. An adaptive backstepping slide mode control method is proposed for pneumatic position servo system. The proposed method designs adaptive slide mode controller using backstepping design technique. The controller parameter adaptive law is derived from Lyapunov analysis to guarantee the stability of the system. A theorem is testified to show that the state of closed-loop system is uniformly bounded, and the closed-loop system is stable. The advantages of the proposed method include that system dynamic model parameters are not required for the controller design, uncertain parameters bounds are not need, and the bulk and expensive pressure sensor is not needed as well. Experimental results show that the designed controller can achieve better tracking performance, as compared with some existing methods.

  17. Servo control booster system for minimizing following error

    DOEpatents

    Wise, W.L.

    1979-07-26

    A closed-loop feedback-controlled servo system is disclosed which reduces command-to-response error to the system's position feedback resolution least increment, ..delta..S/sub R/, on a continuous real-time basis, for all operational times of consequence and for all operating speeds. The servo system employs a second position feedback control loop on a by exception basis, when the command-to-response error greater than or equal to ..delta..S/sub R/, to produce precise position correction signals. When the command-to-response error is less than ..delta..S/sub R/, control automatically reverts to conventional control means as the second position feedback control loop is disconnected, becoming transparent to conventional servo control means. By operating the second unique position feedback control loop used herein at the appropriate clocking rate, command-to-response error may be reduced to the position feedback resolution least increment. The present system may be utilized in combination with a tachometer loop for increased stability.

  18. Ac traction gets on track

    SciTech Connect

    O`Connor, L.

    1995-09-01

    This article describes inverter-based ac traction systems which give freight locomotives greater adhesion, pulling power, and braking capacity. In the 1940s, dc traction replaced the steam engine as a source of train propulsion, and it has ruled the freight transportation industry ever since. But now, high-performance ac-traction systems, with their unprecedented levels of pulling power and adhesion, are becoming increasingly common on America`s freight railroads. In thousands of miles of demonstration tests, today`s ac-traction systems have outperformed traditional dc-motor driven systems. Major railroad companies are convinced enough of the benefits of ac traction to have integrated it into their freight locomotives.

  19. Design and Implementation of the Control System for a 2 kHz Rotary Fast Tool Servo

    SciTech Connect

    Montesanti, R C; Trumper, D L

    2004-03-29

    This paper presents a summary of the performance of our 2 kHz rotary fast tool servo and an overview of its control systems. We also discuss the loop shaping techniques used to design the power amplifier current control loop and the implementation of that controller in an op-amp circuit. The design and development of the control system involved a long list of items including: current compensation; tool position compensation; notch filter design and phase stabilizing with an additional pole for a plant with an undamped resonance; adding viscous damping to the fast tool servo; voltage budget for driving real and reactive loads; dealing with unwanted oscillators; ground loops; digital-to-analog converter glitches; electrical noise from the spindle motor switching power supply; and filtering the spindle encoder signal to generate smooth tool tip trajectories. Eventually, all of these topics will be discussed in detail in a Ph.D. thesis that will include this work. For the purposes of this paper, rather than present a diluted discussion that attempts to touch on all of these topics, we will focus on the first item with sufficient detail for providing insight into the design process.

  20. Visual servoing for automatic and uncalibrated percutaneous procedures

    NASA Astrophysics Data System (ADS)

    Loser, Michael H.; Navab, Nassir; Bascle, Benedicte; Taylor, Russell H.

    2000-04-01

    Visual servoing is well established in the field of industrial robotics, when using CCD cameras. This paper describes one of the first medical implementations of uncalibrated visual servoing. To our knowledge, this is the first time that visual servoing is done using x-ray fluoroscopy. In this paper we present a new image based approach for semi-automatically guidance of a needle or surgical tool during percutaneous procedures and is based on a series of granted and pending US patent applications. It is a simple and accurate method which requires no prior calibration or registration. Therefore, no additional sensors, no stererotactic frame and no additional calibration phantom is needed. Our techniques provides accurate 3D alignment of the tool with respect to an anatomic target and estimates the required insertion depth. We implemented and verified this method with three different medical robots at the Computer Integrated Surgery (CIS) Lab at the Johns Hopkins University. First tests were performed using a CCD-camera and a mobile uniplanar x-ray fluoroscope as imaging modality. We used small metal balls of 4 mm in diameter as target points. These targets were placed 60 to 70 mm deep inside a test-phantom. Our method led to correct insertions with mean deviation of 0.20 mm with CCD camera and mean deviation of about 1.5 mm in clinical surrounding with an old x-ray imaging system, where the images were not of best quality. These promising results present this method as a serious alternative to other needle placement techniques, which require cumbersome and time consuming calibration procedures.

  1. Array servo scanning micro EDM of 3D micro cavities

    NASA Astrophysics Data System (ADS)

    Tong, Hao; Li, Yong; Yi, Futing

    2010-12-01

    Micro electro discharge machining (Micro EDM) is a non-traditional processing technology with the special advantages of low set-up cost and few cutting force in machining any conductive materials regardless of their hardness. As well known, die-sinking EDM is unsuitable for machining the complex 3D micro cavity less than 1mm due to the high-priced fabrication of 3D microelectrode itself and its serous wear during EDM process. In our former study, a servo scanning 3D micro-EDM (3D SSMEDM) method was put forward, and our experiments showed it was available to fabricate complex 3D micro-cavities. In this study, in order to improve machining efficiency and consistency accuracy for array 3D micro-cavities, an array-servo-scanning 3D micro EDM (3D ASSMEDM) method is presented considering the complementary advantages of the 3D SSMEDM and the array micro electrodes with simple cross-section. During 3D ASSMEDM process, the array cavities designed by CAD / CAM system can be batch-manufactured by servo scanning layer by layer using array-rod-like micro tool electrodes, and the axial wear of the array electrodes is compensated in real time by keeping discharge gap. To verify the effectiveness of the 3D ASSMEDM, the array-triangle-micro cavities (side length 630 μm) are batch-manufactured on P-doped silicon by applying the array-micro-electrodes with square-cross-section fabricated by LIGA process. Our exploratory experiment shows that the 3D ASSMEDM provides a feasible approach for the batch-manufacture of 3D array-micro-cavities of conductive materials.

  2. Array servo scanning micro EDM of 3D micro cavities

    NASA Astrophysics Data System (ADS)

    Tong, Hao; Li, Yong; Yi, Futing

    2011-05-01

    Micro electro discharge machining (Micro EDM) is a non-traditional processing technology with the special advantages of low set-up cost and few cutting force in machining any conductive materials regardless of their hardness. As well known, die-sinking EDM is unsuitable for machining the complex 3D micro cavity less than 1mm due to the high-priced fabrication of 3D microelectrode itself and its serous wear during EDM process. In our former study, a servo scanning 3D micro-EDM (3D SSMEDM) method was put forward, and our experiments showed it was available to fabricate complex 3D micro-cavities. In this study, in order to improve machining efficiency and consistency accuracy for array 3D micro-cavities, an array-servo-scanning 3D micro EDM (3D ASSMEDM) method is presented considering the complementary advantages of the 3D SSMEDM and the array micro electrodes with simple cross-section. During 3D ASSMEDM process, the array cavities designed by CAD / CAM system can be batch-manufactured by servo scanning layer by layer using array-rod-like micro tool electrodes, and the axial wear of the array electrodes is compensated in real time by keeping discharge gap. To verify the effectiveness of the 3D ASSMEDM, the array-triangle-micro cavities (side length 630 μm) are batch-manufactured on P-doped silicon by applying the array-micro-electrodes with square-cross-section fabricated by LIGA process. Our exploratory experiment shows that the 3D ASSMEDM provides a feasible approach for the batch-manufacture of 3D array-micro-cavities of conductive materials.

  3. Analysis of Dynamic Performances for Servo Drive Hydraulic System

    NASA Astrophysics Data System (ADS)

    Yang, Jianxi; Wang, Liying; Huang, Jian

    Based on the servo drive hydraulic of system, using MATLAB/Simulink software in this paper, the impacts on system dynamic performances are analyzed and simulated of all the parameters (structure parameters J, Dp, and mechanism parameters A1, α, k, V1 CP). According to the relation curve of the main systematic characteristics and dynamic performances obtained from the simulations, it provides advantages for system dynamic performance improvements. The simulation results indicate that dynamic performances can be improved through the reasonable selection of the system structural parameters. Also it laid the theoretical foundation for further study on energy saving of hydraulic injection machine.

  4. Modeling, simulation, and identification of the servo pumps

    NASA Astrophysics Data System (ADS)

    Negoita, C. G.; Vasiliu, D.; Vasiliu, Ne; Calinoiu, C.

    2010-08-01

    This paper contains the results of a systematic research on the steady-state behavior, and the transients occurring in a basic hydrostatic system containing a servo pump. The optimum structure of such a device working in given condition is found step by step, the synthesis stages are alternating with the analysis ones, in order to establish some general synthesis criteria, as well as for creating some images of the design parameters influence on the real system dynamic behavior. The dynamic computation of the servo pumps is based on the experimental researches carried out by the authors on the control force of the variable displacement axial piston pumps. The analysis takes into account the pressure feedback, the rigid or spring mechanical feedback or the electrical position feedback. The theoretical models are developed by AMESim (Advanced Modeling and Simulation Environment for Systems Engineering). The experimental tests were performed by the aid of LabVIEW software from National Instruments Corporation in the frame of a national certified laboratory set up by the aid of Parker Hannifin Corporation.

  5. Visual Servoing: A technology in search of an application

    SciTech Connect

    Feddema, J.T.

    1994-05-01

    Considerable research has been performed on Robotic Visual Servoing (RVS) over the past decade. Using real-time visual feedback, researchers have demonstrated that robotic systems can pick up moving parts, insert bolts, apply sealant, and guide vehicles. With the rapid improvements being made in computing and image processing hardware, one would expect that every robot manufacturer would have a RVS option by the end of the 1990s. So why aren`t the Fanucs, ABBs, Adepts, and Motomans of the world investing heavily in RVS? I would suggest four seasons: cost, complexity, reliability, and lack of demand. Solutions to the first three are approaching the point where RVS could be commercially available; however, the lack of demand is keeping RVS from becoming a reality in the near future. A new set of applications is needed to focus near term RVS development. These must be applications which currently do not have solutions. Once developed and working in one application area, the technology is more likely to quickly spread to other areas. DOE has several applications that are looking for technological solutions, such as agile weapons production, weapons disassembly, decontamination and dismantlement of nuclear facilities, and hazardous waste remediation. This paper will examine a few of these areas and suggest directions for application-driven visual servoing research.

  6. Building large mosaics of confocal edomicroscopic images using visual servoing.

    PubMed

    Rosa, Benoît; Erden, Mustafa Suphi; Vercauteren, Tom; Herman, Benoît; Szewczyk, Jérôme; Morel, Guillaume

    2013-04-01

    Probe-based confocal laser endomicroscopy provides real-time microscopic images of tissues contacted by a small probe that can be inserted in vivo through a minimally invasive access. Mosaicking consists in sweeping the probe in contact with a tissue to be imaged while collecting the video stream, and process the images to assemble them in a large mosaic. While most of the literature in this field has focused on image processing, little attention has been paid so far to the way the probe motion can be controlled. This is a crucial issue since the precision of the probe trajectory control drastically influences the quality of the final mosaic. Robotically controlled motion has the potential of providing enough precision to perform mosaicking. In this paper, we emphasize the difficulties of implementing such an approach. First, probe-tissue contacts generate deformations that prevent from properly controlling the image trajectory. Second, in the context of minimally invasive procedures targeted by our research, robotic devices are likely to exhibit limited quality of the distal probe motion control at the microscopic scale. To cope with these problems visual servoing from real-time endomicroscopic images is proposed in this paper. It is implemented on two different devices (a high-accuracy industrial robot and a prototype minimally invasive device). Experiments on different kinds of environments (printed paper and ex vivo tissues) show that the quality of the visually servoed probe motion is sufficient to build mosaics with minimal distortion in spite of disturbances. PMID:23192481

  7. Consideration of plant behaviour in optimal servo-compensator design

    NASA Astrophysics Data System (ADS)

    Moase, W. H.; Manzie, C.

    2016-07-01

    Where the most prevalent optimal servo-compensator formulations penalise the behaviour of an error system, this paper considers the problem of additionally penalising the actual states and inputs of the plant. Doing so has the advantage of enabling the penalty function to better resemble an economic cost. This is especially true of problems where control effort needs to be sensibly allocated across weakly redundant inputs or where one wishes to use penalties to soft-constrain certain states or inputs. It is shown that, although the resulting cost function grows unbounded as its horizon approaches infinity, it is possible to formulate an equivalent optimisation problem with a bounded cost. The resulting optimisation problem is similar to those in earlier studies but has an additional 'correction term' in the cost function, and a set of equality constraints that arise when there are redundant inputs. A numerical approach to solve the resulting optimisation problem is presented, followed by simulations on a micro-macro positioner that illustrate the benefits of the proposed servo-compensator design approach.

  8. Parametric electric motor study

    SciTech Connect

    Adams, D.; Stahura, D.

    1995-04-30

    Technology for the axial gap motor was developed by DOE with an investment of approximately $15 million. This development effort is for motor technologies of high power density and high efficiency. Such motors that are also small and light-weight are not available on the commercial market because high-power motors have typically been used in large industrial applications where small size and light weight are not requirements. AC Delco has been developing motors since 1918 and is interested in leveraging its research and development dollars to produce an array of motor systems for vehicles and to develop a future line of propulsion products. The DOE focus of the study was applied to machining applications. The most attractive feature of this motor is the axial air gap, which may make possible the removal of the motor`s stationary component from a total enclosure of the remainder of the machine if the power characteristics are adequate. The objectives of this project were to evaluate alternative electric drive systems for machine tools and automotive electric drive systems and to select a best machine type for each of those applications. A major challenge of this project was to produce a small, light-weight, highly efficient motor at a cost-effective price. The project developed machine and machine drive systems and design criteria for the range of applications. The final results included the creation of a baseline for developing electric vehicle powertrain system designs, conventional vehicle engine support system designs, and advanced machine tool configurations. In addition, an axial gap permanent magnet motor was built and tested, and gave, said one engineer involved, a sterling performance. This effort will commercialize advanced motor technology and extend knowledge and design capability in the most efficient electric machine design known today.

  9. ac propulsion system for an electric vehicle

    NASA Technical Reports Server (NTRS)

    Geppert, S.

    1980-01-01

    It is pointed out that dc drives will be the logical choice for current production electric vehicles (EV). However, by the mid-80's, there is a good chance that the price and reliability of suitable high-power semiconductors will allow for a competitive ac system. The driving force behind the ac approach is the induction motor, which has specific advantages relative to a dc shunt or series traction motor. These advantages would be an important factor in the case of a vehicle for which low maintenance characteristics are of primary importance. A description of an EV ac propulsion system is provided, taking into account the logic controller, the inverter, the motor, and a two-speed transmission-differential-axle assembly. The main barrier to the employment of the considered propulsion system in EV is not any technical problem, but inverter transistor cost.

  10. Modeling Of Permanent Magnet Motor Drives

    NASA Astrophysics Data System (ADS)

    Pillay, P.; Krishnan, R.

    1987-10-01

    Recent research has indicated that the permanent magnet motor drives which include the permanent magnet synchronous motor (PMSM) and the brushless DC motor (BDCM) could become serious competitors to the induction motor for servo applications. The PMSM has a sinusoidal back emf and requires sinusoidal stator currents to produce constant torque while the BDCM has a trapezoidal back emf and requires rectangular stator currents to produce constant torque. The PMSM is very similar to the wound rotor synchronous machine except that the PMSM that is used for servo applications tend not to have any damper windings and excitation is provided by a permanent magnet instead of a field winding. Hence the d,q model of the PMSM can be derived from the well known model of the synchronous machine with the equations of the damper windings and field current dynamics removed. Because of the nonsinusoidal variation of the mutual inductances between the stator and rotor in the BDCM, it is also shown in this paper that no particular advantage exists in transforming the abc equations of the BCDM to the d,q frame. Hence the solution of the original abc equations is proposed for the BDCM.

  11. Image compensation using wavelet transform for tilt servo control in holographic data storage system

    NASA Astrophysics Data System (ADS)

    Kim, Jang Hyun; Yang, Hyunseok

    2015-09-01

    A holographic data storage system is very important in the division of a mass storage device. In this regard, tilt servo control is the main problem in the study of holographic data storage system. Tracking servo and tilt servo control are very important research area in holographic data storage system. In this paper, we propose two algorithms. The first algorithm is image compensation using the wavelet transform method and the second algorithm is intelligent servo control using fuzzy rules for the exact tilt control in the holographic data storage system. We need to obtain a good pattern in binary data using a CMOS camera. We have developed two step-by-step operations. Firstly, to obtain exact image data, image data compensation carried out by the wavelet transform method. Finally, we have realized an intelligence control model using fuzzy rules, which was generated by a subtractive clustering algorithm. Therefore, we control radial and tangential tilt servo control using fuzzy rules in a holographic data storage system and perform image data compensation by the wavelet transform method. Our system does not require responses in the tilt servo control system. Therefore, this system has the advantage terms of time. Consequently, the practical pattern of tilt servo control was found by an intelligence algorithm through image processing in the holographic data storage system.

  12. Piloted Simulator Investigation of Techniques to Achieve Attitude Command Response with Limited Authority Servos

    NASA Technical Reports Server (NTRS)

    Key, David L.; Heffley, Robert K.

    2002-01-01

    The purpose of the study was to develop generic design principles for obtaining attitude command response in moderate to aggressive maneuvers without increasing SCAS series servo authority from the existing +/- 10%. In particular, to develop a scheme that would work on the UH-60 helicopter so that it can be considered for incorporation in future upgrades. The basic math model was a UH-60A version of GENHEL. The simulation facility was the NASA-Ames Vertical Motion Simulator (VMS). Evaluation tasks were Hover, Acceleration-Deceleration, and Sidestep, as defined in ADS-33D-PRF for Degraded Visual Environment (DVE). The DVE was adjusted to provide a Usable Cue Environment (UCE) equal to two. The basic concept investigated was the extent to which the limited attitude command authority achievable by the series servo could be supplemented by a 10%/sec trim servo. The architecture used provided angular rate feedback to only the series servo, shared the attitude feedback between the series and trim servos, and when the series servo approached saturation the attitude feedback was slowly phased out. Results show that modest use of the trim servo does improve pilot ratings, especially in and around hover. This improvement can be achieved with little degradation in response predictability during moderately aggressive maneuvers.

  13. Weighted feature selection criteria for visual servoing of a telerobot

    NASA Technical Reports Server (NTRS)

    Feddema, John T.; Lee, C. S. G.; Mitchell, O. R.

    1989-01-01

    Because of the continually changing environment of a space station, visual feedback is a vital element of a telerobotic system. A real time visual servoing system would allow a telerobot to track and manipulate randomly moving objects. Methodologies for the automatic selection of image features to be used to visually control the relative position between an eye-in-hand telerobot and a known object are devised. A weighted criteria function with both image recognition and control components is used to select the combination of image features which provides the best control. Simulation and experimental results of a PUMA robot arm visually tracking a randomly moving carburetor gasket with a visual update time of 70 milliseconds are discussed.

  14. Fuzzy self-learning control for magnetic servo system

    NASA Technical Reports Server (NTRS)

    Tarn, J. H.; Kuo, L. T.; Juang, K. Y.; Lin, C. E.

    1994-01-01

    It is known that an effective control system is the key condition for successful implementation of high-performance magnetic servo systems. Major issues to design such control systems are nonlinearity; unmodeled dynamics, such as secondary effects for copper resistance, stray fields, and saturation; and that disturbance rejection for the load effect reacts directly on the servo system without transmission elements. One typical approach to design control systems under these conditions is a special type of nonlinear feedback called gain scheduling. It accommodates linear regulators whose parameters are changed as a function of operating conditions in a preprogrammed way. In this paper, an on-line learning fuzzy control strategy is proposed. To inherit the wealth of linear control design, the relations between linear feedback and fuzzy logic controllers have been established. The exercise of engineering axioms of linear control design is thus transformed into tuning of appropriate fuzzy parameters. Furthermore, fuzzy logic control brings the domain of candidate control laws from linear into nonlinear, and brings new prospects into design of the local controllers. On the other hand, a self-learning scheme is utilized to automatically tune the fuzzy rule base. It is based on network learning infrastructure; statistical approximation to assign credit; animal learning method to update the reinforcement map with a fast learning rate; and temporal difference predictive scheme to optimize the control laws. Different from supervised and statistical unsupervised learning schemes, the proposed method learns on-line from past experience and information from the process and forms a rule base of an FLC system from randomly assigned initial control rules.

  15. Low-cost, fast-response drive circuit for electromagnetic torque motors

    NASA Technical Reports Server (NTRS)

    Zeller, J. R.

    1968-01-01

    Fast-response coil drive circuit, for electromagnetic torque motors, reduces the inductive coil time constant with a minimum of circuit sophistication. The low-cost modulator servoamplifier is used with a compatible preamplifier stage which provides the servo-loop function of summing, adjustable gain and compensation.

  16. An open source digital servo for atomic, molecular, and optical physics experiments

    SciTech Connect

    Leibrandt, D. R. Heidecker, J.

    2015-12-15

    We describe a general purpose digital servo optimized for feedback control of lasers in atomic, molecular, and optical physics experiments. The servo is capable of feedback bandwidths up to roughly 1 MHz (limited by the 320 ns total latency); loop filter shapes up to fifth order; multiple-input, multiple-output control; and automatic lock acquisition. The configuration of the servo is controlled via a graphical user interface, which also provides a rudimentary software oscilloscope and tools for measurement of system transfer functions. We illustrate the functionality of the digital servo by describing its use in two example scenarios: frequency control of the laser used to probe the narrow clock transition of {sup 27}Al{sup +} in an optical atomic clock, and length control of a cavity used for resonant frequency doubling of a laser.

  17. Slow tool servo diamond turning of optical freeform surface for astigmatic contact lens

    NASA Astrophysics Data System (ADS)

    Chen, Chun-Chieh; Cheng, Yuan-Chieh; Hsu, Wei-Yao; Chou, Hsiao-Yu; Wang, Pei-Jen; Tsai, Din Ping

    2011-09-01

    Three ultra-precision machining processes namely fast tool servo, slow tool servo and diamond milling, are frequently used to produce optical freeform surface. Slow tool servo machining has the advantages of no extra attachment and fast setting-up, however the three dimensional tool shape compensation and tool-path generation must be conducted carefully for getting high form accuracy and fine surface finish. This research aimed to develop a model of three dimensional tool shape compensation for generating 3D tool path in slow tool servo diamond turning of asymmetrically toric surface for astigmatic contact lens. The form accuracy of freeform surface was measured by ultra-high accuracy 3D profilometer (UA3P) with user define function. After correction, the form error is less than 0.5μm both in X- and Y-direction and the surface roughness is less than 5nm.

  18. An open source digital servo for atomic, molecular, and optical physics experiments

    NASA Astrophysics Data System (ADS)

    Leibrandt, D. R.; Heidecker, J.

    2015-12-01

    We describe a general purpose digital servo optimized for feedback control of lasers in atomic, molecular, and optical physics experiments. The servo is capable of feedback bandwidths up to roughly 1 MHz (limited by the 320 ns total latency); loop filter shapes up to fifth order; multiple-input, multiple-output control; and automatic lock acquisition. The configuration of the servo is controlled via a graphical user interface, which also provides a rudimentary software oscilloscope and tools for measurement of system transfer functions. We illustrate the functionality of the digital servo by describing its use in two example scenarios: frequency control of the laser used to probe the narrow clock transition of 27Al+ in an optical atomic clock, and length control of a cavity used for resonant frequency doubling of a laser.

  19. Servo control system for friction drive with ultra-low speed and high accuracy

    NASA Astrophysics Data System (ADS)

    Yang, Shihai; Zhang, Zhenchao

    2008-07-01

    Due to its high accuracy and good performance at low speed, friction drive is widely used in turntable and large astronomical telescopes such as LAMOST and Keck. Especially, friction drives are implemented on the axes of azimuth, altitude and field rotation in LAMOST telescope. This paper describes the study on servo control system for friction drive with ultra-low speed and high accuracy. The principle, constitution, control algorithm and realization of servo system based on friction drive are analyzed and explored.

  20. Disturbances Analysis Considering an Effective Servo System for Holographic Disc Drive

    NASA Astrophysics Data System (ADS)

    Lim, Sung-Yong; Lee, JongJin; Lee, Jae-Seong; Jeong, Wooyoung; Yang, Hyunseok; Park, No-Cheol; Park, Kyoung-Su; Park, Young-Pil

    2013-09-01

    In conventional angle-multiplexed holographic data storage, data pages are recorded and are retrieved with stop-go rotation. In this paper, we propose an effective servo method based on the disturbance analysis of holographic disc drives. Our experimental results indicate that the eccentricity and deviation of the disc provide sufficient information in the disturbance estimations to stabilize the servo system. The results also show that the vibration due to stop-go rotation can be ignored.

  1. An Online Observer for Minimization of Pulsating Torque in SMPM Motors

    PubMed Central

    Roșca, Lucian

    2016-01-01

    A persistent problem of surface mounted permanent magnet (SMPM) motors is the non-uniformity of the developed torque. Either the motor design or the motor control needs to be improved in order to minimize the periodic disturbances. This paper proposes a new control technique for reducing periodic disturbances in permanent magnet (PM) electro-mechanical actuators, by advancing a new observer/estimator paradigm. A recursive estimation algorithm is implemented for online control. The compensating signal is identified and added as feedback to the control signal of the servo motor. Compensation is evaluated for different values of the input signal, to show robustness of the proposed method. PMID:27089182

  2. An Online Observer for Minimization of Pulsating Torque in SMPM Motors.

    PubMed

    Roșca, Lucian; Duguleană, Mihai

    2016-01-01

    A persistent problem of surface mounted permanent magnet (SMPM) motors is the non-uniformity of the developed torque. Either the motor design or the motor control needs to be improved in order to minimize the periodic disturbances. This paper proposes a new control technique for reducing periodic disturbances in permanent magnet (PM) electro-mechanical actuators, by advancing a new observer/estimator paradigm. A recursive estimation algorithm is implemented for online control. The compensating signal is identified and added as feedback to the control signal of the servo motor. Compensation is evaluated for different values of the input signal, to show robustness of the proposed method. PMID:27089182

  3. Visual servoing of a laser ablation based cochleostomy

    NASA Astrophysics Data System (ADS)

    Kahrs, Lüder A.; Raczkowsky, Jörg; Werner, Martin; Knapp, Felix B.; Mehrwald, Markus; Hering, Peter; Schipper, Jörg; Klenzner, Thomas; Wörn, Heinz

    2008-03-01

    The aim of this study is a defined, visually based and camera controlled bone removal by a navigated CO II laser on the promontory of the inner ear. A precise and minimally traumatic opening procedure of the cochlea for the implantation of a cochlear implant electrode (so-called cochleostomy) is intended. Harming the membrane linings of the inner ear can result in damage of remaining organ functions (e.g. complete deafness or vertigo). A precise tissue removal by a laser-based bone ablation system is investigated. Inside the borehole the pulsed laser beam is guided automatically over the bone by using a two mirror galvanometric scanner. The ablation process is controlled by visual servoing. For the detection of the boundary layers of the inner ear the ablation area is monitored by a color camera. The acquired pictures are analyzed by image processing. The results of this analysis are used to control the process of laser ablation. This publication describes the complete system including image processing algorithms and the concept for the resulting distribution of single laser pulses. The system has been tested on human cochleae in ex-vivo studies. Further developments could lead to safe intraoperative openings of the cochlea by a robot based surgical laser instrument.

  4. Hydraulic servo for friction coupling element of automatic transmission

    SciTech Connect

    Sumiya, K.; Watanabe, K.; Kubo, S.

    1987-09-01

    A hydraulic servo is described for a friction coupling element in an automatic transmission including a casing, comprising: an annular drum fixed to the automatic transmission casing and having an outer cylinder, as in inner cylinder, a sidewall connecting the outer and inner cylinders, and an intermediate cylinder connected to the sidewall between the outer and inner cylinders to divide the interior of the drum into outer and inner annular spaces; a piston slidably mounted within the outer annular space, between the outer and intermediate cylinders, the piston having a terminal axially extending guide sleeve portion; and return biasing means including: a connecting member having one end fixed to the piston and abutting the guide sleeve portion and the other end located in the inner annular space, between the inner cylinder and the intermediate cylinder; a retainer fixed to the inner cylinder, at a position axially inward of the guide sleeve with respect to the sidewall when the piston is fully retracted, and; return springs interposed within the inner annular space between the other end of the connecting member and the retainer.

  5. Linear quadratic servo control of a reusable rocket engine

    NASA Technical Reports Server (NTRS)

    Musgrave, Jeffrey L.

    1991-01-01

    A design method for a servo compensator is developed in the frequency domain using singular values. The method is applied to a reusable rocket engine. An intelligent control system for reusable rocket engines was proposed which includes a diagnostic system, a control system, and an intelligent coordinator which determines engine control strategies based on the identified failure modes. The method provides a means of generating various linear multivariable controllers capable of meeting performance and robustness specifications and accommodating failure modes identified by the diagnostic system. Command following with set point control is necessary for engine operation. A Kalman filter reconstructs the state while loop transfer recovery recovers the required degree of robustness while maintaining satisfactory rejection of sensor noise from the command error. The approach is applied to the design of a controller for a rocket engine satisfying performance constraints in the frequency domain. Simulation results demonstrate the performance of the linear design on a nonlinear engine model over all power levels during mainstage operation.

  6. Neuronal mechanisms of motor learning and motor memory consolidation in healthy old adults.

    PubMed

    Berghuis, K M M; Veldman, M P; Solnik, S; Koch, G; Zijdewind, I; Hortobágyi, T

    2015-06-01

    It is controversial whether or not old adults are capable of learning new motor skills and consolidate the performance gains into motor memory in the offline period. The underlying neuronal mechanisms are equally unclear. We determined the magnitude of motor learning and motor memory consolidation in healthy old adults and examined if specific metrics of neuronal excitability measured by magnetic brain stimulation mediate the practice and retention effects. Eleven healthy old adults practiced a wrist extension-flexion visuomotor skill for 20 min (MP, 71.3 years), while a second group only watched the templates without movements (attentional control, AC, n = 11, 70.5 years). There was 40 % motor learning in MP but none in AC (interaction, p < 0.001) with the skill retained 24 h later in MP and a 16 % improvement in AC. Corticospinal excitability at rest and during task did not change, but when measured during contraction at 20 % of maximal force, it strongly increased in MP and decreased in AC (interaction, p = 0.002). Intracortical inhibition at rest and during the task decreased and facilitation at rest increased in MP, but these metrics changed in the opposite direction in AC. These neuronal changes were especially profound at retention. Healthy old adults can learn a new motor skill and consolidate the learned skill into motor memory, processes that are most likely mediated by disinhibitory mechanisms. These results are relevant for the increasing number of old adults who need to learn and relearn movements during motor rehabilitation. PMID:25956604

  7. Powerline Coupler for Windmill Motor/Generators

    NASA Technical Reports Server (NTRS)

    Nola, F.

    1985-01-01

    Efficiency at low windspeed increased by firing-angle control. Power coupled from wind-driven induction motor/generator to ac powerline with help from circuit. Circuit reduces power consumed by field windings thereby improving efficiency at low windspeeds. Circuit includes zerocrossing detector, ramp generator and comparator similar to those used to set firing angles for thyristors in power factor motor controllers.

  8. The Ball Bearing as a Motor.

    ERIC Educational Resources Information Center

    Gruenberg, H.

    1978-01-01

    Develops a theory to explain the effect that, when a current passes through a ball bearing, it can act as a motor. The motor can run in either direction on both DC and AC and can be self-starting on DC. Presents some experimental results in support of the theory. (Author/GA)

  9. Four quadrant control of induction motors

    NASA Technical Reports Server (NTRS)

    Hansen, Irving G.

    1991-01-01

    Induction motors are the nation's workhorse, being the motor of choice in most applications due to their simple rugged construction. It has been estimated that 14 to 27 percent of the country's total electricity use could be saved with adjustable speed drives. Until now, induction motors have not been suited well for variable speed or servo-drives, due to the inherent complexity, size, and inefficiency of their variable speed controls. Work at NASA Lewis Research Center on field oriented control of induction motors using pulse population modulation method holds the promise for the desired drive electronics. The system allows for a variable voltage to frequency ratio which enables the user to operate the motor at maximum efficiency, while having independent control of both the speed and torque of an induction motor in all four quadrants of the speed torque map. Multiple horsepower machine drives were demonstrated, and work is on-going to develop a 20 hp average, 40 hp peak class of machine. The pulse population technique, results to date, and projections for implementation of this existing new motor control technology are discussed.

  10. 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.

  11. 21 CFR 880.5100 - AC-powered adjustable hospital bed.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false AC-powered adjustable hospital bed. 880.5100... Therapeutic Devices § 880.5100 AC-powered adjustable hospital bed. (a) Identification. An AC-powered... electric motor and remote controls that can be operated by the patient to adjust the height and...

  12. 21 CFR 880.5100 - AC-powered adjustable hospital bed.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false AC-powered adjustable hospital bed. 880.5100... Therapeutic Devices § 880.5100 AC-powered adjustable hospital bed. (a) Identification. An AC-powered... electric motor and remote controls that can be operated by the patient to adjust the height and...

  13. 21 CFR 880.5100 - AC-powered adjustable hospital bed.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false AC-powered adjustable hospital bed. 880.5100... Therapeutic Devices § 880.5100 AC-powered adjustable hospital bed. (a) Identification. An AC-powered... electric motor and remote controls that can be operated by the patient to adjust the height and...

  14. 21 CFR 880.5100 - AC-powered adjustable hospital bed.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false AC-powered adjustable hospital bed. 880.5100... Therapeutic Devices § 880.5100 AC-powered adjustable hospital bed. (a) Identification. An AC-powered... electric motor and remote controls that can be operated by the patient to adjust the height and...

  15. Trade Electricity. Motors & Controls--Level 3. Standardized Curriculum.

    ERIC Educational Resources Information Center

    New York City Board of Education, Brooklyn, NY. Office of Occupational and Career Education.

    This curriculum guide consists of seven modules on motors and controls, one of the three divisions of the standardized trade electricity curriculum in high schools in New York City. The seven modules cover the following subjects: energy conservation wiring, direct current (DC) motor repair and rewinding, DC motor controls, alternating current (AC)…

  16. Visual Servoed Three-Dimensional Cell Rotation System.

    PubMed

    Wang, Zenan; Latt, Win Tun; Tan, Steven Yih Min; Ang, Wei Tech

    2015-10-01

    Three-dimensional (3-D) positioning and orientation of embryos/oocytes is necessary to facilitate micromanipulation tasks such as cell injection and cellular structural biopsy commonly performed under a microscope. Conventional cell orientation is performed manually by using a vacuum equipped micropipette to aspirate and release the cell, which is a trial-and-error approach. The conventional method relies heavily on the skill of the operator; it also suffers from low precision, low success rate and low controllability. These drawbacks illustrate the need for a systematic 3-D cell rotational system to automate the cell orientation process. In this paper, we present a noninvasive single cell rotation system that can automatically orientate a zebrafish embryo to a desired position when both the cytoplasm and the yolk are in the focal plane. A three-point-contact model for cell rotation that involves a custom-designed rotational stage is introduced to provide precise rotational position control. A vision recognition algorithm is also proposed to enable the visual servoing function of the system. Experimental results show that the proposed system can achieve high success rates of 92.5% (x-axis rotation with 40 trails) and 97.5% (about the z-axis with 80 trails). The system can also successfully complete 3-D cell orientation at an average speed of 31 s/cell with a high in-plane rotation accuracy of 0.3 (°) . As a high precise, high controllable and deterministic cell manipulating system, it provides a starting point for automated cell manipulation for intracytoplasmic sperm injection and embryo biopsy for preimplantation genetic diagnosis. PMID:25993702

  17. Adaptive tool servo diamond turning for enhancing machining efficiency and surface quality of freeform optics.

    PubMed

    Zhu, Zhiwei; To, Suet

    2015-08-10

    Fast tool servo/ slow tool servo (FTS/STS) diamond turning is a very promising technique for the generation of freeform optics. However, the currently adopted constant scheme for azimuth sampling and side-feeding motion possesses no adaptation to surface shape variation, leading to the non-uniform surface quality and low machining efficiency. To overcome this defect, this paper reports on a novel adaptive tool servo (ATS) diamond turning technique which is essentially based on the novel two-degree-of-freedom (2-DOF) FTS/STS. In the ATS, the sampling interval and the side-feeding motion are actively controlled at any cutting point to adapt the machining process to shape variation of the desired surface, making both the sampling induced interpolation error and the side-feeding induced residual tool mark be within the desired tolerances. Characteristic of the required cutting motion suggests that besides the conventional z-axis servo motion, another servo motion along the x-axis synthesizing by the c-axis is mandatory for implementing the ATS. Comparative studies of surface generation of typical micro-structured surfaces in FTS/STS and ATS are thoroughly conducted both theoretically and experimentally. The result demonstrates that the ATS outperforms the FTS/STS with improved surface quality while simultaneously enhanced machining efficiency. PMID:26367879

  18. Robust Hinfinity position control synthesis of an electro-hydraulic servo system.

    PubMed

    Milić, Vladimir; Situm, Zeljko; Essert, Mario

    2010-10-01

    This paper focuses on the use of the techniques based on linear matrix inequalities for robust H(infinity) position control synthesis of an electro-hydraulic servo system. A nonlinear dynamic model of the hydraulic cylindrical actuator with a proportional valve has been developed. For the purpose of the feedback control an uncertain linearized mathematical model of the system has been derived. The structured (parametric) perturbations in the electro-hydraulic coefficients are taken into account. H(infinity) controller extended with an integral action is proposed. To estimate internal states of the electro-hydraulic servo system an observer is designed. Developed control algorithms have been tested experimentally in the laboratory model of an electro-hydraulic servo system. PMID:20655534

  19. Simulation of a spatial, servo-hydraulic test facility for space structures

    NASA Technical Reports Server (NTRS)

    Leimbach, K.-D.; Hahn, H.

    1994-01-01

    In this paper different control concepts for servo-hydraulic test facilities are derived using exact linearization techniques. Based on different linear and nonlinear models of the test table and the actuator dynamics several nonlinear controllers of different complexity are derived. The closed loop system performance of the controlled servo-hydraulic test facility is tested in various computer simulations using both, standard test signals and large test signals as system inputs. The simulation results turn out, that in case of standard input signals the test facility controller must include a linear test table mechanics model and a nonlinear servo-hydraulic actuator model. Additional simulations demonstrate the robustness of the control concept selected for standard test signals with respect to variations of plant parameters.

  20. Precision Position Control of Pneumatic Servo Table Embedded with Aerostatic Bearing

    NASA Astrophysics Data System (ADS)

    Tsai, Ming-Hung; Hsu, Tzu-Yung; Pai, Kei-Ren; Shih, Ming-Chang

    This paper treats the control of a pneumatic servo table combining the air cylinders and sliding guides embedded with aerostatic bearing. Since compressed air flows into the small gap between the bearing and the sliding guide, the cylinder floats around the air film and on the guide surface of the table. The friction forces of the pneumatic servo table are measured, and the relation of frictional force and speed is plotted. The hybrid self-tuning fuzzy controller with the velocity compensators and dead-zone are proposed in this paper. From the experimental results, in case of different position, the positioning accuracy can reach the 0.04μm.

  1. Beam-waveguide antenna servo design issues for tracking low earth-orbiting satellites

    NASA Astrophysics Data System (ADS)

    Gawronski, W. K.; Mellstrom, J. A.

    1993-11-01

    Upcoming NASA missions will require tracking of low-orbit satellites. As a consequence, NASA antennas will be required to track satellites at higher rates than for the current deep space missions. This article investigates servo design issues for the 34-m beam-waveguide antennas that track low-orbit satellites. This includes upgrading the servo with a feedforward loop, using a monopulse controller design, and reducing tracking errors through either proper choice of elevation pinion location, application of a notch filter, or adjustment of the elevation drive amplifier gain. Finally, improvement of the signal-to-noise ratio through averaging of the over-sampled monopulse signal is described.

  2. Beam-Waveguide Antenna Servo Design Issues for Tracking Low-Earth-Orbiting Satellites

    NASA Astrophysics Data System (ADS)

    Gawronski, W. K.; Mellstrom, J. A.

    1993-07-01

    Upcoming NASA missions will require tracking of low-orbit satellites. As a consequence, NASA antennas will be required to track satellites at higher rates than for the current deep space missions. This article investigates servo design issues for the 34-m beam-waveguide antennas that track low-orbit satellites. This includes upgrading the servo with a feedforward loop, using a monopulse controller design, and treducing tracking errors through either proper choice of elevation pinion location, application of a notch filter, or adjustment of the elevation drive amplifier gain. Finally, improvement of the signal-to-noise ratio through averaging of the oversampled monopulse signal is described.

  3. Analysis of an electrohydraulic aircraft control surface servo and comparison with test results

    NASA Technical Reports Server (NTRS)

    Edwards, J. W.

    1972-01-01

    An analysis of an electrohydraulic aircraft control-surface system is made in which the system is modeled as a lumped, two-mass, spring-coupled system controlled by a servo valve. Both linear and nonlinear models are developed, and the effects of hinge-moment loading are included. Transfer functions of the system and approximate literal factors of the transfer functions for several cases are presented. The damping action of dynamic pressure feedback is analyzed. Comparisons of the model responses with results from tests made on a highly resonant rudder control-surface servo indicate the adequacy of the model. The effects of variations in hinge-moment loading are illustrated.

  4. State-feedback stabilisation for stochastic non-holonomic mobile robots with uncertain visual servoing parameters

    NASA Astrophysics Data System (ADS)

    Zhang, Dongkai; Wang, Chaoli; Wei, Guoliang; Zhang, Hengjun; Chen, Hua

    2014-07-01

    The stabilising problem of stochastic non-holonomic mobile robots with uncertain parameters based on visual servoing is addressed in this paper. The model of non-holonomic mobile robots based on visual servoing is extended to the stochastic case, where their forward velocity and angular velocity are both subject to some stochastic disturbances. Based on backstepping technique, state-feedback stabilising controllers are designed for stochastic non-holonomic mobile robots. A switching control strategy for the original system is presented. The proposed controllers guarantee that the closed-loop system is asymptotically stabilised at the zero equilibrium point in probability.

  5. Beam-waveguide antenna servo design issues for tracking low earth-orbiting satellites

    NASA Technical Reports Server (NTRS)

    Gawronski, W. K.; Mellstrom, J. A.

    1993-01-01

    Upcoming NASA missions will require tracking of low-orbit satellites. As a consequence, NASA antennas will be required to track satellites at higher rates than for the current deep space missions. This article investigates servo design issues for the 34-m beam-waveguide antennas that track low-orbit satellites. This includes upgrading the servo with a feedforward loop, using a monopulse controller design, and reducing tracking errors through either proper choice of elevation pinion location, application of a notch filter, or adjustment of the elevation drive amplifier gain. Finally, improvement of the signal-to-noise ratio through averaging of the over-sampled monopulse signal is described.

  6. Adaptive Servo-Ventilation for Central Sleep Apnea in Systolic Heart Failure

    PubMed Central

    Cowie, Martin R.; Woehrle, Holger; Wegscheider, Karl; Angermann, Christiane; d’Ortho, Marie-Pia; Erdmann, Erland; Levy, Patrick; Simonds, Anita K.; Somers, Virend K.; Zannad, Faiez; Teschler, Helmut

    2016-01-01

    BACKGROUND Central sleep apnea is associated with poor prognosis and death in patients with heart failure. Adaptive servo-ventilation is a therapy that uses a noninvasive ventilator to treat central sleep apnea by delivering servo-controlled inspiratory pressure support on top of expiratory positive airway pressure. We investigated the effects of adaptive servo-ventilation in patients who had heart failure with reduced ejection fraction and predominantly central sleep apnea. METHODS We randomly assigned 1325 patients with a left ventricular ejection fraction of 45% or less, an apnea–hypopnea index (AHI) of 15 or more events (occurrences of apnea or hypopnea) per hour, and a predominance of central events to receive guideline-based medical treatment with adaptive servo-ventilation or guideline-based medical treatment alone (control). The primary end point in the time-to-event analysis was the first event of death from any cause, lifesaving cardiovascular intervention (cardiac transplantation, implantation of a ventricular assist device, resuscitation after sudden cardiac arrest, or appropriate lifesaving shock), or unplanned hospitalization for worsening heart failure. RESULTS In the adaptive servo-ventilation group, the mean AHI at 12 months was 6.6 events per hour. The incidence of the primary end point did not differ significantly between the adaptive servo-ventilation group and the control group (54.1% and 50.8%, respectively; hazard ratio, 1.13; 95% confidence interval [CI], 0.97 to 1.31; P = 0.10). All-cause mortality and cardiovascular mortality were significantly higher in the adaptive servo-ventilation group than in the control group (hazard ratio for death from any cause, 1.28; 95% CI, 1.06 to 1.55; P = 0.01; and hazard ratio for cardiovascular death, 1.34; 95% CI, 1.09 to 1.65; P = 0.006). CONCLUSIONS Adaptive servo-ventilation had no significant effect on the primary end point in patients who had heart failure with reduced ejection fraction and

  7. Position tracking control of a synchronous reluctance motor

    SciTech Connect

    Geoghan, A.J.; Carroll, J.J.

    1995-12-31

    The synchronous reluctance (SynR) motor is an attractive candidate for high-performance servo drive systems for various reasons. An integrator back-stepping technique is used to design a trajectory tracking control strategy for SynR motors driving inertial loads. A d-q model which describes the dynamical behavior of the SynR motor is introduced; based on this model, a voltage level controller is proposed which theoretically provides globally uniform asymptotically stable (GUAS) motor trajectory tracking given exact model knowledge and full state feedback (i.e., rotor position, velocity, and the per phase winding currents). The performance of the proposed voltage level controller is verified using computer simulation.

  8. Motor-operated valve (MOV) actuator motor and gearbox testing

    SciTech Connect

    DeWall, K.; Watkins, J.C.; Bramwell, D.

    1997-07-01

    Researchers at the Idaho National Engineering and Environmental Laboratory tested the performance of electric motors and actuator gearboxes typical of the equipment installed on motor-operated valves used in nuclear power plants. Using a test stand that simulates valve closure loads against flow and pressure, the authors tested five electric motors (four ac and one dc) and three gearboxes at conditions a motor might experience in a power plant, including such off-normal conditions as operation at high temperature and reduced voltage. They also monitored the efficiency of the actuator gearbox. All five motors operated at or above their rated starting torque during tests at normal voltages and temperatures. For all five motors, actual torque losses due to voltage degradation were greater than the losses calculated by methods typically used for predicting motor torque at degraded voltage conditions. For the dc motor the actual torque losses due to elevated operating temperatures were greater than the losses calculated by the typical predictive method. The actual efficiencies of the actuator gearboxes were generally lower than the running efficiencies published by the manufacturer and were generally nearer the published pull-out efficiencies. Operation of the gearbox at elevated temperature did not affect the operating efficiency.

  9. Reducing the net torque and flow ripple effects of multiple hydraulic piston motor drives

    NASA Technical Reports Server (NTRS)

    Bartos, R. D.

    1992-01-01

    The torque and flow ripple effects which result when multiple hydraulic motors are used to drive a single motion of a mechanical device can significantly affect the way in which the device performs. This article presents a mathematical model describing the torque and flow ripple effects of a bent-axis hydraulic piston motor. The model is used to show how the ripple magnitude can be reduced when multiple motors are used to drive a motion. A discussion of the hydraulic servo system of the 70-m antennas located with the Deep Space Network is included to demonstrate the application of the concepts presented.

  10. 27. INTERIOR VIEW LOOKING SOUTHWEST IN THE ELECTRICAL MOTOR ROOM. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    27. INTERIOR VIEW LOOKING SOUTHWEST IN THE ELECTRICAL MOTOR ROOM. FROM LEFT TO RIGHT. DC GENERATOR, AC MOTOR, OLD DC GENERATOR, OPENING FOR THE BELT TO THE CLUTCH ASSEMBLY FOR THE MILL POWER SYSTEM. THE BOARDS THAT ARE ASKEW WERE PROTECTION AROUND THE DRIVE BELT. THE SMALL MOTOR IN THE FOREGROUND IS THE MOTOR THAT MOST RECENTLY POWERED THE MILL'S BELT DRIVE SYSTEM. - Standard Gold Mill, East of Bodie Creek, Northeast of Bodie, Bodie, Mono County, CA

  11. ACS Quicklook PDF products

    NASA Astrophysics Data System (ADS)

    Suchkov, Anatoly

    1999-12-01

    This report details the features of the ACS quicklook PDF products produced by the HST data pipeline. The requirements closely follow the design of paper products recommended by the Data Quality Committee, with appropriate changes required to fully support ACS.

  12. Proof-of-Concept Demonstration Results for Robotic Visual Servo Controllers

    SciTech Connect

    Chawda, P.V.

    2004-09-22

    There is significant motivation to provide robotic systems with improved autonomy as a means to significantly accelerate deactivation and decommissioning operations while also reducing the associated costs, removing human operators from hazardous environments, and reducing the required burden and skill of human operators. To achieve improved autonomy, fundamental research is focused on the challenges of developing visual servo controllers. The challenge in developing these controllers is that a camera provides 2-dimensional image information about the 3-dimensional Euclidean-space through a perspective (range dependent) projection that can be corrupted by uncertainty in the camera calibration matrix. Disturbances in this relationship (i.e., corruption in the sensor information) propagate erroneous information to the feedback controller of the robot, leading to potentially unpredictable task execution. This technical manual describes 3 proof-of-concept demonstrations of visual servo controllers developed from fundamental research aimed at these challenges. Specifically, one section describes the implementation of a cooperative visual servo control scheme with a camera-in-hand and a fixed camera to track a moving target despite uncertainty in the camera calibration and the unknown constant distance from the camera to a target where the camera is mounted on the end-effector of a 6 degrees-of-freedom hydraulic robot manipulator. The next section describes the implementation of 2 homography-based visual servo tracking and regulation controllers for a mobile robot with a calibrated camera despite an unknown time-varying distance from the camera to a target.

  13. Parametric identification of a servo-hydraulic actuator for real-time hybrid simulation

    NASA Astrophysics Data System (ADS)

    Qian, Yili; Ou, Ge; Maghareh, Amin; Dyke, Shirley J.

    2014-10-01

    In a typical Real-time Hybrid Simulation (RTHS) setup, servo-hydraulic actuators serve as interfaces between the computational and physical substructures. Time delay introduced by actuator dynamics and complex interaction between the actuators and the specimen has detrimental effects on the stability and accuracy of RTHS. Therefore, a good understanding of servo-hydraulic actuator dynamics is a prerequisite for controller design and computational simulation of RTHS. This paper presents an easy-to-use parametric identification procedure for RTHS users to obtain re-useable actuator parameters for a range of payloads. The critical parameters in a linearized servo-hydraulic actuator model are optimally obtained from genetic algorithms (GA) based on experimental data collected from various specimen mass/stiffness combinations loaded to the target actuator. The actuator parameters demonstrate convincing convergence trend in GA. A key feature of this parametric modeling procedure is its re-usability under different testing scenarios, including different specimen mechanical properties and actuator inner-loop control gains. The models match well with experimental results. The benefit of the proposed parametric identification procedure has been demonstrated by (1) designing an H∞ controller with the identified system parameters that significantly improves RTHS performance; and (2) establishing an analysis and computational simulation of a servo-hydraulic system that help researchers interpret system instability and improve design of experiments.

  14. IMAGE-BASED VISUAL SERVOING FOR ROBOTIC SYSTEMS: A NONLINEAR LYAPUNOV-BASED CONTROL APPROACH

    EPA Science Inventory

    The objective of this project is to enable current and future EM robots with an increased ability to perceive and interact with unstructured and unknown environments through the use of camera-based visual servo controlled robots. The scientific goals of this research are to devel...

  15. A Matlab/Simulink-Based Interactive Module for Servo Systems Learning

    ERIC Educational Resources Information Center

    Aliane, N.

    2010-01-01

    This paper presents an interactive module for learning both the fundamental and practical issues of servo systems. This module, developed using Simulink in conjunction with the Matlab graphical user interface (Matlab-GUI) tool, is used to supplement conventional lectures in control engineering and robotics subjects. First, the paper introduces the…

  16. Wireless transmission of power and information through one high-frequency resonant AC link inverter for robot manipulator applications

    SciTech Connect

    Kawamura, Atsuo; Ishioka, K.; Hirai, J.

    1996-05-01

    A contactless decentralized power supply is proposed with communication capability through only one transformer. A prototype of wireless transmission system of power and information (WTPI system) was built, and the two-axis position controls of servo motors were achieved by transferring the power and signal through one rotatable high-frequency transformer. The proposed concept can be applied for robotics and numerical control (NC) machines.

  17. New method to improve dynamic stiffness of electro-hydraulic servo systems

    NASA Astrophysics Data System (ADS)

    Bai, Yanhong; Quan, Long

    2013-09-01

    Most current researches working on improving stiffness focus on the application of control theories. But controller in closed-loop hydraulic control system takes effect only after the controlled position is deviated, so the control action is lagged. Thus dynamic performance against force disturbance and dynamic load stiffness can’t be improved evidently by advanced control algorithms. In this paper, the elementary principle of maintaining piston position unchanged under sudden external force load change by charging additional oil is analyzed. On this basis, the conception of raising dynamic stiffness of electro hydraulic position servo system by flow feedforward compensation is put forward. And a scheme using double servo valves to realize flow feedforward compensation is presented, in which another fast response servo valve is added to the regular electro hydraulic servo system and specially utilized to compensate the compressed oil volume caused by load impact in time. The two valves are arranged in parallel to control the cylinder jointly. Furthermore, the model of flow compensation is derived, by which the product of the amplitude and width of the valve’s pulse command signal can be calculated. And determination rules of the amplitude and width of pulse signal are concluded by analysis and simulations. Using the proposed scheme, simulations and experiments at different positions with different force changes are conducted. The simulation and experimental results show that the system dynamic performance against load force impact is largely improved with decreased maximal dynamic position deviation and shortened settling time. That is, system dynamic load stiffness is evidently raised. This paper proposes a new method which can effectively improve the dynamic stiffness of electro-hydraulic servo systems.

  18. Motor Starters

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The power factor controller (PFC) was invented by a NASA engineer. It matches voltage with a motor's actual need by sensing shifts in the relationship between voltage and current flow. With the device, power can be trimmed as much as 65%. Intellinet adopted this technology and designed "soft start" and "load-responsive" control modes to start engines gradually and recycle voltage without reducing motor speed. Other features are lower motor heat and faster fault identification.

  19. Motor syndromes.

    PubMed

    Corea, Francesco; Micheli, Sara

    2012-01-01

    Motor disturbances alone or associated with other focal deficits are the most common symptoms suggesting a neurovascular event. An appropriate clinical assessment of these signs and symptoms may help physicians to better diagnose and to both better treat and predict outcome. In this paper the main clinical features of motor deficit are described together with other motor-related events such as ataxia and movement disturbances. PMID:22377850

  20. The ac propulsion system for an electric vehicle, phase 1

    NASA Technical Reports Server (NTRS)

    Geppert, S.

    1981-01-01

    A functional prototype of an electric vehicle ac propulsion system was built consisting of a 18.65 kW rated ac induction traction motor, pulse width modulated (PWM) transistorized inverter, two speed mechanically shifted automatic transmission, and an overall drive/vehicle controller. Design developmental steps, and test results of individual components and the complex system on an instrumented test frame are described. Computer models were developed for the inverter, motor and a representative vehicle. A preliminary reliability model and failure modes effects analysis are given.

  1. EXT-II: a second generation advanced ac propulsion system

    SciTech Connect

    Bates, B.; Patil, P.B.; Ciccarelli, M.F.

    1986-01-01

    This paper discusses the characteristics of the concept and includes discussion of the system constraints, including traction battery constraints, and brief descriptions of the major subsystems being developed. The components discussed include: the system controller, dc to ac inverter, an internal permanent magnet ac motor and a two-speed automatic transmission with an integral final drive and differential. The motor and transmission are on a common axis and are integrated into one compact unit that is integral with the rear axle of the vehicle.

  2. Levitation forces in bearingless permanent magnet motors

    SciTech Connect

    Amrhein, W.; Silber, S.; Nenninger, K.

    1999-09-01

    Bearingless motors combine brushless AC-motors with active magnetic bearings by the integration of two separate winding systems (torque and radial levitation force windings with different pole pairs) in one housing. This paper gives an insight into the influences of the motor design on the levitation force and torque generation. It is shown that especially for machines with small air gaps it can be very important to choose the right design parameters. Increasing the permanent magnet height in order to increase the motor torque can result in a remarkable reduction of radial forces. The interrelationships are discussed on the basis of Maxwell and Lorentz forces acting upon the stator surface. The investigations are presented for a bearingless low cost motor, suited for pump, fan or blower applications. The presented motor needs only four coils for operation.

  3. Novel method for driving the ultrasonic motor.

    PubMed

    Kim, Hyeoung woo; Dong, Shuxiang; Laoratanakul, Pitak; Uchino, Kenji; Park, Tae gone

    2002-10-01

    This paper reports a novel driving method for an annular plate-type ultrasonic motor. Instead of the direct current/alternating current (DC/AC) converter type driver using conventional electromagnetic transformer, a compact disc-type piezoelectric transformer is used to obtain high voltage output for driving the ultrasonic motor. The piezoelectric transformer is operated in the radial vibration mode at resonance frequency close to the resonance frequency of the ultrasonic motor. Later, it was found that the piezoelectric transformer could drive the ultrasonic motor, even if their resonance frequencies are not exactly the same by incorporating the matching network in the circuit. The maximum speed of the ultrasonic motor obtained by using this driving method is over 300 rpm. It is believed that the results of this study will have impact on the integration and miniaturization of the ultrasonic motor and its driving circuit. PMID:12403137

  4. Reluctance and doubly-excited reluctance motors

    NASA Astrophysics Data System (ADS)

    Heyne, C. J.; El-Antably, A. M.

    1984-11-01

    Since the energy crisis in 1974, there was increasing awareness of conserving energy. Industrial ac motors from 1 to 125 hp are estimated to consume 60% of the total electricity produced in the United States. Significant energy conservation could be achieved if the efficiency of these motors is improved. The work described was sponsored by the Division of Electric Energy Systems (EES) of the United States Department of Energy (DOE) through a subcontract with the Power Systems Technology Program at the Oak Ridge National Laboratory (Oak Ridge, Tennessee, USA). The design, analysis, and test of two types of motors designed to have a high efficiency and power factor are described. The first type, reluctance motors (RMs), are similar to synchronous motors but without dc excitation. A novel 3-phase RM was designed and tested, and it was found to have superior efficiency when compared with a similar induction motor.

  5. Reluctance and doubly-excited reluctance motors

    SciTech Connect

    Heyne, C.J.; El-Antably, A.M.

    1984-11-01

    Since the energy crisis in 1974, there has been increasing awareness of conserving energy. Industrial ac motors from 1 to 125 hp are estimated to consume 60% of the total electricity produced in the United States. Significant energy conservation could be achieved if the efficiency of these motors is improved. The work described in this report was sponsored by the Division of Electric Energy Systems (EES) of the United States Department of Energy (DOE) through a subcontract with the Power Systems Technology Program at the Oak Ridge National Laboratory (Oak Ridge, Tennessee, USA). This work deals with the design, analysis, and test of two types of motors designed to have a high efficiency and power factor. The first type, reluctance motors (RMs), are similar to synchronous motors but without dc excitation. A novel 3-phase RM has been designed and tested, and it was found to have superior efficiency when compared with a similar induction motor.

  6. A linear magnetic motor and generator

    NASA Technical Reports Server (NTRS)

    Studer, P. A.

    1980-01-01

    In linear magnetic motor and generator suitable for remote and hostile environments, magnetic forces drive reciprocating shaft along its axis. Actuator shaft is located in center of cylindrical body and may be supported by either contacting or noncontacting bearings. When device operates as bidirectional motor, drive coil selectively adds and subtracts magnetic flux to and from flux paths, producing forces that drive actuator along axis. When actuator is driven by external reciprocating engine, device becomes ac generator.

  7. Field oriented control of induction motors

    NASA Technical Reports Server (NTRS)

    Burrows, Linda M.; Zinger, Don S.; Roth, Mary Ellen

    1990-01-01

    Induction motors have always been known for their simple rugged construction, but until lately were not suitable for variable speed or servo drives due to the inherent complexity of the controls. With the advent of field oriented control (FOC), however, the induction motor has become an attractive option for these types of drive systems. An FOC system which utilizes the pulse population modulation method to synthesize the motor drive frequencies is examined. This system allows for a variable voltage to frequency ratio and enables the user to have independent control of both the speed and torque of an induction motor. A second generation of the control boards were developed and tested with the next point of focus being the minimization of the size and complexity of these controls. Many options were considered with the best approach being the use of a digital signal processor (DSP) due to its inherent ability to quickly evaluate control algorithms. The present test results of the system and the status of the optimization process using a DSP are discussed.

  8. Active control of residual tool marks for freeform optics functionalization by novel biaxial servo assisted fly cutting.

    PubMed

    Zhu, Zhiwei; To, Suet; Zhang, Shaojian

    2015-09-01

    The inherent residual tool marks (RTM) with particular patterns highly affect optical functions of the generated freeform optics in fast tool servo or slow tool servo (FTS/STS) diamond turning. In the present study, a novel biaxial servo assisted fly cutting (BSFC) method is developed for flexible control of the RTM to be a functional micro/nanotexture in freeform optics generation, which is generally hard to achieve in FTS/STS diamond turning. In the BSFC system, biaxial servo motions along the z-axis and side-feeding directions are mainly adopted for primary surface generation and RTM control, respectively. Active control of the RTM from the two aspects, namely, undesired effect elimination or effective functionalization, are experimentally demonstrated by fabricating a typical F-theta freeform surface with scattering homogenization and two functional microstructures with imposition of secondary phase gratings integrating both reflective and diffractive functions. PMID:26368889

  9. Molecular motors

    NASA Astrophysics Data System (ADS)

    Allemand, Jean François Desbiolles, Pierre

    2015-10-01

    How do we move? More precisely, what are the molecular mechanisms that can explain that our muscles, made of very small components can move at a osopic scale? To answer these questions we must introduce molecular motors. Those motors are proteins, or small protein assemblies that, in our cells, transform chemical energy into mechanical work. Then, like we could do for a oscopic motor, used in a car or in a fan, we are going to study the basic behavior of these molecular machines, present what are their energy sources, calculate their power, their yield. If molecular motors are crucial for our oscopic movements, we are going to see that they are also essential to cellular transport and that considering the activity of some enzymes as molecular motors bring some interesting new insights on their activity.

  10. Active control of static pressure drop caused by hydraulic servo-actuator engage

    SciTech Connect

    Janlovic, J.

    1994-12-31

    Pressure drop caused by propagation of expansion waves in the source pipeline of fast high cyclic hydraulic actuator produces possible anomalies in its function. To prevent pressure drop it is possible to minimize wave effects by active control of actuator servo-valve throttle leakage. In the paper is presented synthesis of possible discrete active control of hydraulic actuator and its servo-valve for prevention expansion wave pressure drop. Control synthesis is based on static pressure increasing with decreasing of fluid flow velocity, which can be realized by lower throttle leakage. Some of the effects of assumed control are shown on corresponding diagrams of control valve throttle motion, piston displacement and its corresponding linear velocity.

  11. Inherent limitations of fixed-time, servo-controlled radiometric calorimetry

    SciTech Connect

    Wetzel, J.R.; Lemming, J.F.; Duff, M.F.

    1987-01-01

    Interest has been shown in using fixed-time, servo-controlled calorimetry to shorten the measurement times for certain samples that require low precision values (3 to 5%). This type of calorimeter measurement could be particularly useful for screening scrap samples to determine whether there is a need for a more accurate measurement or for certain confirmatory measurements for which low precision numbers are sufficient. The equipment required for this type of measurement is a servo-controlled calorimeter and a preconditioning unit. Samples to be measured are placed in the preconditioning unit, which is maintained at the internal temperature of the calorimeter. The power value for the sample is determined at a fixed time after loading into the calorimeter, for example, 30 min. When a calorimeter is operated using a fixed cutoff time, there are additional sources of uncertainty that need to be considered. The major factors affecting the uncertainty of the calorimetry power values are discussed. 2 refs., 4 figs.

  12. Chiari malformation and central sleep apnea syndrome: efficacy of treatment with adaptive servo-ventilation*

    PubMed Central

    do Vale, Jorge Marques; Silva, Eloísa; Pereira, Isabel Gil; Marques, Catarina; Sanchez-Serrano, Amparo; Torres, António Simões

    2014-01-01

    The Chiari malformation type I (CM-I) has been associated with sleep-disordered breathing, especially central sleep apnea syndrome. We report the case of a 44-year-old female with CM-I who was referred to our sleep laboratory for suspected sleep apnea. The patient had undergone decompressive surgery 3 years prior. An arterial blood gas analysis showed hypercapnia. Polysomnography showed a respiratory disturbance index of 108 events/h, and all were central apnea events. Treatment with adaptive servo-ventilation was initiated, and central apnea was resolved. This report demonstrates the efficacy of servo-ventilation in the treatment of central sleep apnea syndrome associated with alveolar hypoventilation in a CM-I patient with a history of decompressive surgery. PMID:25410846

  13. Automatic guidance of an ultrasound probe by visual servoing based on B-mode image moments.

    PubMed

    Mebarki, Rafik; Krupa, Alexandre; Collewet, Christophe

    2008-01-01

    We propose a new visual servo approach to automatically control in real-time the full motion of a 2D ultrasound (US) probe held by a medical robot in order to reach a desired image of motionless soft tissue object in B-mode ultrasound imaging. Combinations of image moments of the observed object cross-section are used as feedback information in the visual control scheme. These visual features are extracted in real-time from the US image thanks to a fast image segmentation method. Simulations performed with a static US volume containing an egg-shaped object, and ex-vivo experiments using a robotized US probe that interacts with a motionless rabbit heart immersed in water, show the validity of this new approach and its robustness to different perturbations. This method shows promise for a variety of US-guided medical interventions that require real-time servoing. PMID:18982623

  14. A new state space model for the NASA/JPL 70-meter antenna servo controls

    NASA Technical Reports Server (NTRS)

    Hill, R. E.

    1987-01-01

    A control axis referenced model of the NASA/JPL 70-m antenna structure is combined with the dynamic equations of servo components to produce a comprehansive state variable (matrix) model of the coupled system. An interactive Fortran program for generating the linear system model and computing its salient parameters is described. Results are produced in a state variable, block diagram, and in factored transfer function forms to facilitate design and analysis by classical as well as modern control methods.

  15. A servo controlled gradient loading triaxial model test system for deep-buried cavern.

    PubMed

    Chen, Xu-guang; Zhang, Qiang-yong; Li, Shu-cai

    2015-10-01

    A servo controlled gradient loading model test system is developed to simulate the gradient geostress in deep-buried cavern. This system consists of the gradient loading apparatus, the digital servo control device, and the measurement system. Among them, the gradient loading apparatus is the main component which is used for exerting load onto the model. This loading apparatus is placed inside the counterforce wall/beam and is divided to several different loading zones, with each loading zone independently controlled. This design enables the gradient loading. Hence, the "real" geostress field surrounding the deep-buried cavern can be simulated. The loading or unloading process can be controlled by the human-computer interaction machines, i.e., the digital servo control system. It realizes the automation and visualization of model loading/unloading. In addition, this digital servo could control and regulate hydraulic loading instantaneously, which stabilizes the geostress onto the model over a long term. During the loading procedure, the collision between two adjacent loading platens is also eliminated by developing a guide frame. This collision phenomenon is induced by the volume shrinkage of the model when compressed in true 3D state. In addition, several accurate measurements, including the optical and grating-based method, are adopted to monitor the small deformation of the model. Hence, the distortion of the model could be accurately measured. In order to validate the performance of this innovative model test system, a 3D geomechanical test was conducted on a simulated deep-buried underground reservoir. The result shows that the radial convergence increases rapidly with the release of the stress in the reservoir. Moreover, the deformation increases with the increase of the gas production rate. This observation is consistence with field observation in petroleum engineering. The system is therefore capable of testing deep-buried engineering structures. PMID

  16. Reconfigurable Flight Control Design using a Robust Servo LQR and Radial Basis Function Neural Networks

    NASA Technical Reports Server (NTRS)

    Burken, John J.

    2005-01-01

    This viewgraph presentation reviews the use of a Robust Servo Linear Quadratic Regulator (LQR) and a Radial Basis Function (RBF) Neural Network in reconfigurable flight control designs in adaptation to a aircraft part failure. The method uses a robust LQR servomechanism design with model Reference adaptive control, and RBF neural networks. During the failure the LQR servomechanism behaved well, and using the neural networks improved the tracking.

  17. A servo controlled gradient loading triaxial model test system for deep-buried cavern

    NASA Astrophysics Data System (ADS)

    Chen, Xu-guang; Zhang, Qiang-yong; Li, Shu-cai

    2015-10-01

    A servo controlled gradient loading model test system is developed to simulate the gradient geostress in deep-buried cavern. This system consists of the gradient loading apparatus, the digital servo control device, and the measurement system. Among them, the gradient loading apparatus is the main component which is used for exerting load onto the model. This loading apparatus is placed inside the counterforce wall/beam and is divided to several different loading zones, with each loading zone independently controlled. This design enables the gradient loading. Hence, the "real" geostress field surrounding the deep-buried cavern can be simulated. The loading or unloading process can be controlled by the human-computer interaction machines, i.e., the digital servo control system. It realizes the automation and visualization of model loading/unloading. In addition, this digital servo could control and regulate hydraulic loading instantaneously, which stabilizes the geostress onto the model over a long term. During the loading procedure, the collision between two adjacent loading platens is also eliminated by developing a guide frame. This collision phenomenon is induced by the volume shrinkage of the model when compressed in true 3D state. In addition, several accurate measurements, including the optical and grating-based method, are adopted to monitor the small deformation of the model. Hence, the distortion of the model could be accurately measured. In order to validate the performance of this innovative model test system, a 3D geomechanical test was conducted on a simulated deep-buried underground reservoir. The result shows that the radial convergence increases rapidly with the release of the stress in the reservoir. Moreover, the deformation increases with the increase of the gas production rate. This observation is consistence with field observation in petroleum engineering. The system is therefore capable of testing deep-buried engineering structures.

  18. A servo controlled gradient loading triaxial model test system for deep-buried cavern

    SciTech Connect

    Chen, Xu-guang; Zhang, Qiang-yong; Li, Shu-cai

    2015-10-15

    A servo controlled gradient loading model test system is developed to simulate the gradient geostress in deep-buried cavern. This system consists of the gradient loading apparatus, the digital servo control device, and the measurement system. Among them, the gradient loading apparatus is the main component which is used for exerting load onto the model. This loading apparatus is placed inside the counterforce wall/beam and is divided to several different loading zones, with each loading zone independently controlled. This design enables the gradient loading. Hence, the “real” geostress field surrounding the deep-buried cavern can be simulated. The loading or unloading process can be controlled by the human-computer interaction machines, i.e., the digital servo control system. It realizes the automation and visualization of model loading/unloading. In addition, this digital servo could control and regulate hydraulic loading instantaneously, which stabilizes the geostress onto the model over a long term. During the loading procedure, the collision between two adjacent loading platens is also eliminated by developing a guide frame. This collision phenomenon is induced by the volume shrinkage of the model when compressed in true 3D state. In addition, several accurate measurements, including the optical and grating-based method, are adopted to monitor the small deformation of the model. Hence, the distortion of the model could be accurately measured. In order to validate the performance of this innovative model test system, a 3D geomechanical test was conducted on a simulated deep-buried underground reservoir. The result shows that the radial convergence increases rapidly with the release of the stress in the reservoir. Moreover, the deformation increases with the increase of the gas production rate. This observation is consistence with field observation in petroleum engineering. The system is therefore capable of testing deep-buried engineering structures.

  19. Vision servoing of robot systems using piecewise continuous controllers and observers

    NASA Astrophysics Data System (ADS)

    Wang, H. P.; Vasseur, C.; Christov, N.; Koncar, V.

    2012-11-01

    This paper deals with the visual servoing of X-Y robot systems using low cost CCD camera. The proposed approach is based on the theory of piecewise continuous systems which are a particular class of hybrid systems with autonomous switching and controlled impulses. Visual trajectory tracking systems comprising piecewise continuous controllers and observers, are developed. Real-time results are given to illustrate the effectiveness of the proposed visual control system.

  20. Image-Based Visual Servoing for Robotic Systems: A Nonlinear Lyapunov-Based Control Approach

    SciTech Connect

    Dixon, Warren

    2004-06-01

    There is significant motivation to provide robotic systems with improved autonomy as a means to significantly accelerate deactivation and decommissioning (D&D) operations while also reducing the associated costs, removing human operators from hazardous environments, and reducing the required burden and skill of human operators. To achieve improved autonomy, this project focused on the basic science challenges leading to the development of visual servo controllers. The challenge in developing these controllers is that a camera provides 2-dimensional image information about the 3-dimensional Euclidean-space through a perspective (range dependent) projection that can be corrupted by uncertainty in the camera calibration matrix and by disturbances such as nonlinear radial distortion. Disturbances in this relationship (i.e., corruption in the sensor information) propagate erroneous information to the feedback controller of the robot, leading to potentially unpredictable task execution. This research project focused on the development of a visual servo control methodology that targets compensating for disturbances in the camera model (i.e., camera calibration and the recovery of range information) as a means to achieve predictable response by the robotic system operating in unstructured environments. The fundamental idea is to use nonlinear Lyapunov-based techniques along with photogrammetry methods to overcome the complex control issues and alleviate many of the restrictive assumptions that impact current robotic applications. The outcome of this control methodology is a plug-and-play visual servoing control module that can be utilized in conjunction with current technology such as feature recognition and extraction to enable robotic systems with the capabilities of increased accuracy, autonomy, and robustness, with a larger field of view (and hence a larger workspace). The developed methodology has been reported in numerous peer-reviewed publications and the

  1. Alternating-Current Motor Drive for Electric Vehicles

    NASA Technical Reports Server (NTRS)

    Krauthamer, S.; Rippel, W. E.

    1982-01-01

    New electric drive controls speed of a polyphase as motor by varying frequency of inverter output. Closed-loop current-sensing circuit automatically adjusts frequency of voltage-controlled oscillator that controls inverter frequency, to limit starting and accelerating surges. Efficient inverter and ac motor would give electric vehicles extra miles per battery charge.

  2. 28. INTERIOR VIEW LOOKING NORTH IN THE ELECTRICAL MOTOR ROOM. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    28. INTERIOR VIEW LOOKING NORTH IN THE ELECTRICAL MOTOR ROOM. CLOSE UP VIEW OF THE OLD DC GENERATOR, APPARATUS ON THE FLOOR ARE FOR THE OPERATION OF TH DC GENERATOR. AN AC MOTOR IS IN THE BACKGROUND RIGHT. - Standard Gold Mill, East of Bodie Creek, Northeast of Bodie, Bodie, Mono County, CA

  3. Performance evaluation and optimization of a fast tool servo for single point diamond turning machines

    NASA Astrophysics Data System (ADS)

    Miller, Arthur C., Jr.; Cuttino, James F.

    1997-11-01

    This paper describes a new, fast tool servo system designed for fabrication of non-rotationally symmetric components using single point diamond turning machines. A prototype device, designed for flexible interfacing to typical machine tool controllers, will be described along with performance testing data of tilted flat and off-axis conic sections. Evaluation data show that servo produced surfaces have an RMS roughness less than 175 angstroms. Techniques for linearizing the hysteretic effects in the piezoelectric actuator are also discussed. The nonlinear effects due to hysteresis are reduced using a dynamic compensator module in conjunction with a linear controller. The compensator samples the reduced using a dynamic compensator module in conjunction with a linear controller. The compensator samples the hysteretic voltage/displacement relationship in real time and modifies the effective gain accordingly. Simulation results indicate that errors in the performance of the system caused by hysteresis in the system can be compensated and reduced by 90 percent. Experimental implementation results in an 80 percent reduction in the motion error caused by hysteresis, but peak-to-valley errors are limited by side effects from the compensation. The uncompensated servo system demonstrated a peak-to-valley error of less than 0.80 micrometer for an off-axis conic section turned on-axis.

  4. Servo-control of water and sodium homeostasis during renal clearance measurements in conscious rats.

    PubMed

    Thomsen, Klaus; Shirley, David G

    2007-01-01

    Servo-controlled fluid and sodium replacement during clearance studies is used in order to prevent loss of body fluid and sodium following diuretic/natriuretic procedures. However, even under control conditions, the use of this technique is sometimes associated with increases in proximal tubular fluid output (assessed by lithium clearance) and excretion rates. The present study examined the reason for these increases. The first series of experiments showed that one cause is volume overloading. This can occur if the servo system is activated from the start, i.e., during the establishment of a suitably high urine flow rate by constant infusion of hypotonic glucose solution. The second series of experiments showed that replacement of blood samples with donor blood can also lead to increases in fractional lithium excretion and accompanying increases in water and sodium excretion, a problem not seen when blood samples are replaced with the animal's own red blood cells resuspended in isotonic saline. When these pitfalls are avoided, servo-controlled sodium and fluid replacement is a reliable technique that makes it possible to study the effects of natriuretic and/or diuretic stimuli without interference from unwanted changes in extracellular volume. PMID:17693706

  5. Autonomous robotic capture of non-cooperative target by adaptive extended Kalman filter based visual servo

    NASA Astrophysics Data System (ADS)

    Dong, Gangqi; Zhu, Zheng H.

    2016-05-01

    This paper presents a real-time, vision-based algorithm for the pose and motion estimation of non-cooperative targets and its application in visual servo robotic manipulator to perform autonomous capture. A hybrid approach of adaptive extended Kalman filter and photogrammetry is developed for the real-time pose and motion estimation of non-cooperative targets. Based on the pose and motion estimates, the desired pose and trajectory of end-effector is defined and the corresponding desired joint angles of the robotic manipulator are derived by inverse kinematics. A close-loop visual servo control scheme is then developed for the robotic manipulator to track, approach and capture the target. Validating experiments are designed and performed on a custom-built six degrees of freedom robotic manipulator with an eye-in-hand configuration. The experimental results demonstrate the feasibility, effectiveness and robustness of the proposed adaptive extended Kalman filter enabled pose and motion estimation and visual servo strategy.

  6. A low-cost, FPGA-based servo controller with lock-in amplifier

    NASA Astrophysics Data System (ADS)

    Yang, G.; Barry, J. F.; Shuman, E. S.; Steinecker, M. H.; DeMille, D.

    2012-10-01

    We describe the design and implementation of a low-cost, FPGA-based servo controller with an integrated waveform synthesizer and lock-in amplifier. This system has been designed with the specific application of laser frequency locking in mind but should be adaptable to a variety of other purposes as well. The system incorporates an onboard waveform synthesizer, a lock-in amplifier, two channels of proportional-integral (PI) servo control, and a ramp generator on a single FPGA chip. The system is based on an inexpensive, off-the-shelf FPGA evaluation board with a wide variety of available accessories, allowing the system to interface with standard laser controllers and detectors while minimizing the use of custom hardware and electronics. Gains, filter constants, and other relevant parameters are adjustable via onboard knobs and switches. These parameters and other information are displayed to the user via an integrated LCD, allowing full operation of the device without an accompanying computer. We demonstrate the performance of the system in a test setup, in which the frequency of a tunable external-cavity diode laser (ECDL) is locked to a resonant optical transmission peak of a Fabry-Perot cavity. In this setup, we achieve a total servo-loop bandwidth of ~ 7 kHz and achieve locking of the ECDL to the cavity with a full-width-at-half-maximum (FWHM) linewidth of ~ 200 kHz.

  7. Performance evaluation and optimization of a fast tool servo for single point diamond turning machines

    SciTech Connect

    Miller, A.C. Jr.; Cuttino, J.F.

    1997-08-01

    This paper describes a new, fast tool servo system for fabricating non-rotationally symmetric components using single point diamond turning machines. A prototype, designed for flexible interfacing to typical machine tool controllers, will be described along with performance testing data of tilted flat and off-axis conic sections. Evaluation data show that servo produced surfaces have an rms roughness less than 175 angstroms (2-200 {mu}m spatial filter). Techniques for linearizing the hysteretic effects in the piezoelectric actuator are also discussed. The nonlinear effects due to hysteresis are reduced using a dynamic compensator module in conjunction with a linear controller. The compensator samples the hysteretic voltage/displacement relation in real time and modifies the effective gain accordingly. Simulation results indicate that errors in the performance of the system caused by hysteresis can be compensated and reduced by 90%. Experimental implementation results in 80% reduction in motion error caused by hysteresis, but peak-to- valley errors are limited by side effects from the compensation. The uncompensated servo system demonstrated a peak-to-valley error of less than 0.80 micrometer for an off-axis conic section turned on-axis.

  8. Motor Controller

    NASA Technical Reports Server (NTRS)

    1988-01-01

    M.H. Marks Enterprises' Power Factor Controller (PFC) matches voltage with motor's actual need. Plugged into a motor, PFC continuously determines motor load by sensing shifts between voltage and current flow. When it senses a light load, it cuts voltage to the minimum needed. It offers potential energy savings ranging from eight percent up to 65 percent depending on the application. Myles Marks started out with the notion of writing an article for Popular Electronics magazine at the same time offering to furnish kits to readers interested in assembling PFC's. Within two weeks from publication he had orders for 500 kits and orders are still coming three years later.

  9. Stepper motor

    NASA Technical Reports Server (NTRS)

    Dekramer, Cornelis

    1994-01-01

    The purpose of this document is to describe the more commonly used permanent magnet stepper motors for spaceflight. It will discuss the mechanical and electrical aspects of the devices, their torque behavior, those parameters which need to be controlled and measured, and test methods to be employed. It will also discuss torque margins, compare these to the existing margin requirements, and determine the applicability of these requirements. Finally it will attempt to generate a set of requirements which will be used in any stepper motor procurement and will fully characterize the stepper motor behavior in a consistent and repeatable fashion.

  10. Advanced electric motor technology: Flux mapping

    NASA Technical Reports Server (NTRS)

    Doane, George B., III; Campbell, Warren; Brantley, Larry W.; Dean, Garvin

    1992-01-01

    This report contains the assumptions, mathematical models, design methodology, and design points involved with the design of an electromechanical actuator (EMA) suitable for directing the thrust vector of a large MSFC/NASA launch vehicle. Specifically the design of such an actuator for use on the upcoming liquid fueled National Launch System (NLS) is considered culminating in a point design of both the servo system and the electric motor needed. A major thrust of the work is in selecting spur gear and roller screw reduction ratios to achieve simultaneously wide bandwidth, maximum power transfer, and disturbance rejection while meeting specified horsepower requirements at a given stroking speed as well as a specified maximum stall force. An innovative feedback signal is utilized in meeting these diverse objectives.

  11. Variable speed induction motor operation from a 20-kHz power bus

    NASA Technical Reports Server (NTRS)

    Hansen, Irving G.

    1989-01-01

    Induction motors are recognized for their simple rugged construction to date, however, their application to variable speed or servo drives has been hampered by limitations on their control. Induction motor drives tend to be complex and to display troublesome low speed characteristics due in part to nonsinusoidal driving voltages. A technique was developed which involves direct synthesis of sinusoidal driving voltages from a high frequency power bus and independent control of frequency and voltages. Separation offrequency and voltage allows independent control of rotor and stator flux, full four-quadrant operation, and instantaneous torque control. Recent test results, current status of the technology, and proposed aerospace applications will be discussed.

  12. Adaptive Motor Resistance Video Game Exercise Apparatus and Method of Use Thereof

    NASA Technical Reports Server (NTRS)

    Reich, Alton (Inventor); Shaw, James (Inventor)

    2015-01-01

    The invention comprises a method and/or an apparatus using computer configured exercise equipment and an electric motor provided physical resistance in conjunction with a game system, such as a video game system, where the exercise system provides real physical resistance to a user interface. Results of user interaction with the user interface are integrated into a video game, such as running on a game console. The resistance system comprises: a subject interface, software control, a controller, an electric servo assist/resist motor, an actuator, and/or a subject sensor. The system provides actual physical interaction with a resistance device as input to the game console and game run thereon.

  13. Variable speed induction motor operation from a 20-kHz power bus

    NASA Technical Reports Server (NTRS)

    Hansen, Irving G.

    1989-01-01

    Induction motors are recognized for their simple rugged construction. To date, however, their application to variable speed or servo drives was hampered by limitations on their control. Induction motor drives tend to be complex and to display troublesome low speed characteristics due in part to nonsinusoidal driving voltages. A technique was developed which involves direct synthesis of sinusoidal driving voltages from a high frequency power bus and independent control of frequency and voltages. Separation of frequency and voltage allows independent control of rotor and stator flux, full four quadrant operation, and instantaneous torque control. Recent test results, current status of the technology, and proposed aerospace applications will be discussed.

  14. A Computer Model for Teaching the Dynamic Behavior of AC Contactors

    ERIC Educational Resources Information Center

    Ruiz, J.-R. R.; Espinosa, A. G.; Romeral, L.

    2010-01-01

    Ac-powered contactors are extensively used in industry in applications such as automatic electrical devices, motor starters, and heaters. In this work, a practical session that allows students to model and simulate the dynamic behavior of ac-powered electromechanical contactors is presented. Simulation is carried out using a rigorous parametric…

  15. Chaotic motors

    NASA Astrophysics Data System (ADS)

    Laroche, C.; Labbé, R.; Pétrélis, F.; Fauve, S.

    2012-02-01

    We show that electric motors and dynamos can be used to illustrate most elementary instabilities or bifurcations discussed in courses on nonlinear oscillators and dynamical systems. These examples are easier to understand and display a richer behavior than the ones commonly used from mechanics, electronics, hydrodynamics, lasers, chemical reactions, and population dynamics. In particular, an electric motor driven by a dynamo can display stationary, Hopf, and codimension-two bifurcations by tuning the driving speed of the dynamo and the electric current in the stator of the electric motor. When the dynamo is driven at constant torque instead of constant rotation rate, chaotic reversals of the generated current and of the angular rotation of the motor are observed. Simple deterministic models are presented which capture the observed dynamical regimes.

  16. Aero-servo-viscoelasticity theory: Lifting surfaces, plates, velocity transients, flutter, and instability

    NASA Astrophysics Data System (ADS)

    Merrett, Craig G.

    Modern flight vehicles are fabricated from composite materials resulting in flexible structures that behave differently from the more traditional elastic metal structures. Composite materials offer a number of advantages compared to metals, such as improved strength to mass ratio, and intentional material property anisotropy. Flexible aircraft structures date from the Wright brothers' first aircraft with fabric covered wooden frames. The flexibility of the structure was used to warp the lifting surface for flight control, a concept that has reappeared as aircraft morphing. These early structures occasionally exhibited undesirable characteristics during flight such as interactions between the empennage and the aft fuselage, or control problems with the elevators. The research to discover the cause and correction of these undesirable characteristics formed the first foray into the field of aeroelasticity. Aeroelasticity is the intersection and interaction between aerodynamics, elasticity, and inertia or dynamics. Aeroelasticity is well suited for metal aircraft, but requires expansion to improve its applicability to composite vehicles. The first is a change from elasticity to viscoelasticity to more accurately capture the solid mechanics of the composite material. The second change is to include control systems. While the inclusion of control systems in aeroelasticity lead to aero-servo-elasticity, more control possibilities exist for a viscoelastic composite material. As an example, during the lay-up of carbon-epoxy plies, piezoelectric control patches are inserted between different plies to give a variety of control options. The expanded field is called aero-servo-viscoelasticity. The phenomena of interest in aero-servo-viscoelasticity are best classified according to the type of structure considered, either a lifting surface or a panel, and the type of dynamic stability present. For both types of structures, the governing equations are integral

  17. Method and apparatus for improved efficiency in a pulse-width-modulated alternating current motor drive

    DOEpatents

    Konrad, C.E.; Boothe, R.W.

    1996-01-23

    A scheme for optimizing the efficiency of an AC motor drive operated in a pulse-width-modulated mode provides that the modulation frequency of the power furnished to the motor is a function of commanded motor torque and is higher at lower torque requirements than at higher torque requirements. 6 figs.

  18. Method and apparatus for improved efficiency in a pulse-width-modulated alternating current motor drive

    DOEpatents

    Konrad, Charles E.; Boothe, Richard W.

    1994-01-01

    A scheme for optimizing the efficiency of an AC motor drive operated in a pulse-width-modulated mode provides that the modulation frequency of the power furnished to the motor is a function of commanded motor torque and is higher at lower torque requirements than at higher torque requirements.

  19. 21 CFR 878.4820 - Surgical instrument motors and accessories/attachments.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Surgical instrument motors and accessories....4820 Surgical instrument motors and accessories/attachments. (a) Identification. Surgical instrument motors and accessories are AC-powered, battery-powered, or air-powered devices intended for use...

  20. Method and apparatus for improved efficiency in a pulse-width-modulated alternating current motor drive

    DOEpatents

    Konrad, Charles E.; Boothe, Richard W.

    1996-01-01

    A scheme for optimizing the efficiency of an AC motor drive operated in a pulse-width-modulated mode provides that the modulation frequency of the power furnished to the motor is a function of commanded motor torque and is higher at lower torque requirements than at higher torque requirements.

  1. Analysis of a three phase induction motor directly from Maxwell's equations

    NASA Astrophysics Data System (ADS)

    Bhattacharjee, Shayak

    2012-01-01

    The torque developed in a three phase AC squirrel cage motor is usually expressed in terms of resistances and reactances of the stator, the rotor, and the motor as a whole. We use Maxwell's equations to find the torque in terms of geometrical parameters. This formulation allows us to estimate the torque developed by a motor without knowing the details of its circuitry.

  2. Method and apparatus for improved efficiency in a pulse-width-modulated alternating current motor drive

    DOEpatents

    Konrad, C.E.; Boothe, R.W.

    1994-02-15

    A scheme for optimizing the efficiency of an AC motor drive operated in a pulse-width-modulated mode provides that the modulation frequency of the power furnished to the motor is a function of commanded motor torque and is higher at lower torque requirements than at higher torque requirements. 6 figures.

  3. Motor torque compensation of an induction electric motor by adjusting a slip command during periods of supposed change in motor temperature

    DOEpatents

    Kelledes, William L.; St. John, Don K.

    1992-01-01

    The present invention maintains constant torque in an inverter driven AC induction motor during variations in rotor temperature. It is known that the torque output of a given AC induction motor is dependent upon rotor temperature. At rotor temperatures higher than the nominal operating condition the rotor impedance increases, reducing the rotor current and motor torque. In a similar fashion, the rotor impedance is reduced resulting in increased rotor current and motor torque when the rotor temperature is lower than the nominal operating condition. The present invention monitors the bus current from the DC supply to the inverter and adjusts the slip frequency of the inverter drive to maintain a constant motor torque. This adjustment is based upon whether predetermined conditions implying increased rotor temperature or decreased rotor temperature exist for longer that a predetermined interval of time.

  4. Microfabricated AC impedance sensor

    DOEpatents

    Krulevitch, Peter; Ackler, Harold D.; Becker, Frederick; Boser, Bernhard E.; Eldredge, Adam B.; Fuller, Christopher K.; Gascoyne, Peter R. C.; Hamilton, Julie K.; Swierkowski, Stefan P.; Wang, Xiao-Bo

    2002-01-01

    A microfabricated instrument for detecting and identifying cells and other particles based on alternating current (AC) impedance measurements. The microfabricated AC impedance sensor includes two critical elements: 1) a microfluidic chip, preferably of glass substrates, having at least one microchannel therein and with electrodes patterned on both substrates, and 2) electrical circuits that connect to the electrodes on the microfluidic chip and detect signals associated with particles traveling down the microchannels. These circuits enable multiple AC impedance measurements of individual particles at high throughput rates with sufficient resolution to identify different particle and cell types as appropriate for environmental detection and clinical diagnostic applications.

  5. Advanced Motors

    SciTech Connect

    Knoth, Edward A; Chelluri, Bhanumathi; Schumaker, Edward J

    2012-12-14

    vProject Summary Transportation energy usage is predicted to increase substantially by 2020. Hybrid vehicles and fuel cell powered vehicles are destined to become more prominent as fuel prices rise with the demand. Hybrid and fuel cell vehicle platforms are both dependent on high performance electric motors. Electric motors for transportation duty will require sizeable low-speed torque to accelerate the vehicle. As motor speed increases, the torque requirement decreases which results in a nearly constant power motor output. Interior permanent magnet synchronous motors (IPMSM) are well suited for this duty. , , These rotor geometries are configured in straight lines and semi circular arc shapes. These designs are of limited configurations because of the lack of availability of permanent magnets of any other shapes at present. We propose to fabricate rotors via a novel processing approach where we start with magnet powders and compact them into a net shape rotor in a single step. Using this approach, widely different rotor designs can be implemented for efficiency. The current limitation on magnet shape and thickness will be eliminated. This is accomplished by co-filling magnet and soft iron powders at specified locations in intricate shapes using specially designed dies and automatic powder filling station. The process fundamentals for accomplishing occurred under a previous Applied Technology Program titled, Motors and Generators for the 21st Century. New efficient motor designs that are not currently possible (or cost prohibitive) can be accomplished by this approach. Such an approach to motor fabrication opens up a new dimension in motor design. Feasibility Results We were able to optimize a IPMSM rotor to take advantage of the powder co-filling and DMC compaction processing methods. The minimum low speed torque requirement of 5 N-m can be met through an optimized design with magnet material having a Br capability of 0.2 T. This level of magnetic performance can

  6. Motor Planning.

    PubMed

    Wong, Aaron L; Haith, Adrian M; Krakauer, John W

    2015-08-01

    Motor planning colloquially refers to any process related to the preparation of a movement that occurs during the reaction time prior to movement onset. However, this broad definition encompasses processes that are not strictly motor-related, such as decision-making about the identity of task-relevant stimuli in the environment. Furthermore, the assumption that all motor-planning processes require processing time, and can therefore be studied behaviorally by measuring changes in the reaction time, needs to be reexamined. In this review, we take a critical look at the processes leading from perception to action and suggest a definition of motor planning that encompasses only those processes necessary for a movement to be executed-that is, processes that are strictly movement related. These processes resolve the ambiguity inherent in an abstract goal by defining a specific movement to achieve it. We propose that the majority of processes that meet this definition can be completed nearly instantaneously, which means that motor planning itself in fact consumes only a small fraction of the reaction time. PMID:24981338

  7. Numerical simulation and experimental study of heat-fluid-solid coupling of double flapper-nozzle servo valve

    NASA Astrophysics Data System (ADS)

    Zhao, Jianhua; Zhou, Songlin; Lu, Xianghui; Gao, Dianrong

    2015-09-01

    The double flapper-nozzle servo valve is widely used to launch and guide the equipment. Due to the large instantaneous flow rate of servo valve working under specific operating conditions, the temperature of servo valve would reach 120°C and the valve core and valve sleeve deform in a short amount of time. So the control precision of servo valve significantly decreases and the clamping stagnation phenomenon of valve core appears. In order to solve the problem of degraded control accuracy and clamping stagnation of servo valve under large temperature difference circumstance, the numerical simulation of heat-fluid-solid coupling by using finite element method is done. The simulation result shows that zero position leakage of servo valve is basically impacted by oil temperature and change of fit clearance. The clamping stagnation is caused by warpage-deformation and fit clearance reduction of the valve core and valve sleeve. The distribution rules of the temperature and thermal-deformation of shell, valve core and valve sleeve and the pressure, velocity and temperature field of flow channel are also analyzed. Zero position leakage and electromagnet's current when valve core moves in full-stroke are tested using Electro-hydraulic Servo-valve Characteristic Test-bed of an aerospace sciences and technology corporation. The experimental results show that the change law of experimental current at different oil temperatures is roughly identical to simulation current. The current curve of the electromagnet is smooth when oil temperature is below 80°C, but the amplitude of current significantly increases and the hairy appears when oil temperature is above 80°C. The current becomes smooth again after the warped valve core and valve sleeve are reground. It indicates that clamping stagnation is caused by warpage-deformation and fit clearance reduction of valve core and valve sleeve. This paper simulates and tests the heat-fluid-solid coupling of double flapper-nozzle servo

  8. AC magnetohydrodynamic microfluidic switch

    SciTech Connect

    Lemoff, A V; Lee, A P

    2000-03-02

    A microfluidic switch has been demonstrated using an AC Magnetohydrodynamic (MHD) pumping mechanism in which the Lorentz force is used to pump an electrolytic solution. By integrating two AC MHD pumps into different arms of a Y-shaped fluidic circuit, flow can be switched between the two arms. This type of switch can be used to produce complex fluidic routing, which may have multiple applications in {micro}TAS.

  9. ACS Symposium Support

    SciTech Connect

    Kenneth D. Jordan

    2010-02-20

    The funds from this DOE grant were used to help cover the travel costs of five students and postdoctoral fellows who attended a symposium on 'Hydration: From Clusters to Aqueous Solutions' held at the Fall 2007 American Chemical Society Meeting in Boston, MA, August 19-23. The Symposium was sponsored by the Physical Chemistry Division, ACS. The technical program for the meeting is available at http://phys-acs.org/fall2007.html.

  10. A new neural net approach to robot 3D perception and visuo-motor coordination

    NASA Technical Reports Server (NTRS)

    Lee, Sukhan

    1992-01-01

    A novel neural network approach to robot hand-eye coordination is presented. The approach provides a true sense of visual error servoing, redundant arm configuration control for collision avoidance, and invariant visuo-motor learning under gazing control. A 3-D perception network is introduced to represent the robot internal 3-D metric space in which visual error servoing and arm configuration control are performed. The arm kinematic network performs the bidirectional association between 3-D space arm configurations and joint angles, and enforces the legitimate arm configurations. The arm kinematic net is structured by a radial-based competitive and cooperative network with hierarchical self-organizing learning. The main goal of the present work is to demonstrate that the neural net representation of the robot 3-D perception net serves as an important intermediate functional block connecting robot eyes and arms.

  11. Cine-servo lens technology for 4K broadcast and cinematography

    NASA Astrophysics Data System (ADS)

    Nurishi, Ryuji; Wakazono, Tsuyoshi; Usui, Fumiaki

    2015-09-01

    Central to the rapid evolution of 4K image capture technology in the past few years, deployment of large-format cameras with Super35mm Single Sensors is increasing in TV production for diverse shows such as dramas, documentaries, wildlife, and sports. While large format image capture has been the standard in the cinema world for quite some time, the recent experiences within the broadcast industry have revealed a variety of requirement differences for large format lenses compared to those of the cinema industry. A typical requirement for a broadcast lens is a considerably higher zoom ratio in order to avoid changing lenses in the middle of a live event, which is mostly not the case for traditional cinema productions. Another example is the need for compact size, light weight, and servo operability for a single camera operator shooting in a shoulder-mount ENG style. On the other hand, there are new requirements that are common to both worlds, such as smooth and seamless change in angle of view throughout the long zoom range, which potentially offers new image expression that never existed in the past. This paper will discuss the requirements from the two industries of cinema and broadcast, while at the same time introducing the new technologies and new optical design concepts applied to our latest "CINE-SERVO" lens series which presently consists of two models, CN7x17KAS-S and CN20x50IAS-H. It will further explain how Canon has realized 4K optical performance and fast servo control while simultaneously achieving compact size, light weight and high zoom ratio, by referring to patent-pending technologies such as the optical power layout, lens construction, and glass material combinations.

  12. 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.

  13. Analog simulation of flux-summing servo-model, phases 1 and 2

    NASA Technical Reports Server (NTRS)

    Hriber, E. J.

    1984-01-01

    The analog simulation was developed for a closed-loop system having an electrohydraulic flux-summing servo valve and actuator with associated inertial load. One-fourth of the system's total forward gain is carried by each of four channels. The present study successfully applied failure mode management techniques to the problem of channel failure. Digital logic circuitry was developed to maintain the overall forward gain of the system at a constant value, in the presence of channel failure. Finally, the stability of the system was verified, and performance characteristics were determined through the use of frequency response methods.

  14. AeroPropulsoServoElasticity: Dynamic Modeling of the Variable Cycle Propulsion System

    NASA Technical Reports Server (NTRS)

    Kopasakis, George

    2012-01-01

    This presentation was made at the 2012 Fundamental Aeronautics Program Technical Conference and it covers research work for the Dynamic Modeling of the Variable cycle Propulsion System that was done under the Supersonics Project, in the area of AeroPropulsoServoElasticity. The presentation covers the objective for the propulsion system dynamic modeling work, followed by the work that has been done so far to model the variable Cycle Engine, modeling of the inlet, the nozzle, the modeling that has been done to model the affects of flow distortion, and finally presenting some concluding remarks and future plans.

  15. 3D micropositioning control based on stereo microscopic visual servoing system

    NASA Astrophysics Data System (ADS)

    Sha, Xiaopeng; Li, Huiguang; Wang, Shuai; Li, Zhiquan; Li, Guoyou

    2014-08-01

    In this paper, the global visual servoing micropositioning control method is analyzed and the imaging model is derived based on the CMO type stereo light microscopes (SLM). The model contains no depth information and the left and right image information is used to obtain the image Jacobian matrix. Considering the kinematics characteristics of micro robot, we design an image-based controller. The experimental and simulation results based on the four degree-offreedom (DOF) microrobot system demonstrate the validity of the theory in this paper.

  16. Development of a fast tool servo in noncircular turning and its control

    NASA Astrophysics Data System (ADS)

    Ma, Haoquan; Tian, Jie; Hu, Dejin

    2013-12-01

    To meet the main requirements of output displacement, bandwidth frequency and accuracy in noncircular turning, a fast tool servo (FTS) system based on piezoelectric (PZT) voltage feedback is developed. A flexure hinge structure is designed to amplify the output of PZT actuator and topology optimization is done to reduce the mass and compliance of the structure so that the output displacement and response frequency of FTS can be improved. A compound controller, into which repetitive techniques, PI and feed-forward control, are introduced, and the method that PZT voltage of the actuator is treated as feedback are put forward. The feasibility and reliability of this system are proved well by turning experiments.

  17. Contactless automated manipulation of mesoscale objects using opto-fluidic actuation and visual servoing.

    PubMed

    Vela, Emir; Hafez, Moustapha; Régnier, Stéphane

    2014-05-01

    This work describes an automated opto-fluidic system for parallel non-contact manipulation of microcomponents. The strong dynamics of laser-driven thermocapillary flows were used to drag microcomponents at high speeds. High-speed flows allowed to manipulate micro-objects in a parallel manner only using a single laser and a mirror scanner. An automated process was implemented using visual servoing with a high-speed camera in order to achieve accurately parallel manipulation. Automated manipulation of two glass beads of 30 up to 300 μm in diameter moving in parallel at speeds in the range of mm/s was demonstrated. PMID:24880415

  18. AC loss in superconducting tapes and cables

    NASA Astrophysics Data System (ADS)

    Oomen, Marijn Pieter

    High-temperature superconductors are developed for use in power-transmission cables, transformers and motors. The alternating magnetic field in these devices causes AC loss, which is a critical factor in the design. The study focuses on multi-filament Bi-2223/Ag tapes exposed to a 50-Hz magnetic field at 77 K. The AC loss is measured with magnetic, electric and calorimetric methods. The results are compared to theoretical predictions based mainly on the Critical-State Model. The loss in high- temperature superconductors is affected by their characteristic properties: increased flux creep, high aspect ratio and inhomogeneties. Filament intergrowths and a low matrix resistivity cause a high coupling-current loss especially when the filaments are fully coupled. When the wide side of the tape is parallel to the external magnetic field, the filaments are decoupled by twisting. In a perpendicular field the filaments can be decoupled only by combining a short twist pitch with a transverse resistivity much higher than that of silver. The arrangement of the inner filaments determines the transverse resistivity. Ceramic barriers around the filaments cause partial decoupling in perpendicular magnetic fields at power frequencies. The resultant decrease in AC loss is greater than the accompanying decrease in critical current. With direct transport current in alternating magnetic field, the transport-current loss is well described with a new model for the dynamic resistance. The Critical- State Model describes well the magnetisation and total AC loss in parallel magnetic fields, at transport currents up to 0.7 times the critical current. When tapes are stacked face-to-face in a winding, the AC-loss density in perpendicular fields is greatly decreased due to the mutual shielding of the tapes. Coupling currents between the tapes in a cable cause an extra AC loss, which is reduced by a careful cable design. The total AC loss in complex devices with many tapes is generally well

  19. Therma motor

    DOEpatents

    Kandarian, R.

    The disclosure is directed to a thermal motor utilizing two tapered prestressed parallel adjacent cylinders lengthwise disposed about one third in a coolant. Heat is applied to contacting portions of the cylinders outside the coolant to cause them to deform and turn. Heat sources such as industrial waste heat, geothermal hot water, solar radiation, etc. can be used.

  20. Motor Neuron Diseases

    MedlinePlus

    ... Enhancing Diversity Find People About NINDS NINDS Motor Neuron Diseases Information Page Condensed from Motor Neuron Diseases ... and Information Publicaciones en Español What are Motor Neuron Diseases? The motor neuron diseases (MNDs) are a ...

  1. Motor Neuron Diseases

    MedlinePlus

    ... called upper motor neurons ) are transmitted to nerve cells in the brain stem and spinal cord (called lower motor neurons ) and from them to particular muscles. Upper motor neurons direct the lower motor neurons ...

  2. Local Voltage Support from Distributed Energy Resources to Prevent Air Conditioner Motor Stalling

    SciTech Connect

    Baone, Chaitanya A; Xu, Yan; Kueck, John D

    2010-01-01

    Microgrid voltage collapse often happens when there is a high percentage of low inertia air-conditioning (AC) motors in the power systems. The stalling of the AC motors results in Fault Induced Delayed Voltage Recovery (FIDVR). A hybrid load model including typical building loads, AC motor loads, and other induction motor loads is built to simulate the motoring stalling phenomena. Furthermore, distributed energy resources (DE) with local voltage support capability are utilized to boost the local bus voltage during a fault, and prevent the motor stalling. The simulation results are presented. The analysis of the simulation results show that local voltage support from multiple DEs can effectively and economically solve the microgrid voltage collapse problem.

  3. Phase and Frequency-Dependent Effects of Transcranial Alternating Current Stimulation on Motor Cortical Excitability.

    PubMed

    Nakazono, Hisato; Ogata, Katsuya; Kuroda, Tsuyoshi; Tobimatsu, Shozo

    2016-01-01

    Transcranial alternating current stimulation (tACS) can entrain ongoing brain oscillations and modulate the motor system in a frequency-dependent manner. Recent animal studies have demonstrated that the phase of a sinusoidal current also has an important role in modulation of neuronal activity. However, the phase effects of tACS on the human motor system are largely unknown. Here, we systematically investigated the effects of tACS phase and frequency on the primary motor cortex (M1) by using motor evoked potentials (MEPs) with transcranial magnetic stimulation (TMS). First, we compared the phase effects (90°, 180°, 270° or 360°) of 10 and 20 Hz tACS on MEPs. The 20 Hz tACS significantly increased M1 excitability compared with the 10 Hz tACS at 90° phase only. Second, we studied the 90° phase effect on MEPs at different tACS frequencies (5, 10, 20 or 40 Hz). The 20 vs. 10 Hz difference was again observed, but the 90° phase in 5 and 40 Hz tACS did not influence M1 excitability. Third, the 90° phase effects of 10 and 20 Hz tACS were compared with sham stimulation. The 90° phase of 20 Hz tACS enhanced MEP amplitudes compared with sham stimulation, but there was no significant effect of 10 Hz tACS. Taken together, we assume that the differential 90° phase effects on 20 Hz and 10 Hz tACS can be attributed to the neural synchronization modulated by tACS. Our results further underline that phase and frequency are the important factors in the effects of tACS on M1 excitability. PMID:27607431

  4. Dynamic analysis of the Green Bank Telescope structure and servo system

    NASA Astrophysics Data System (ADS)

    Ranka, Trupti; Garcia-Sanz, Mario; Symmes, Arthur; Ford, John M.; Weadon, Timothy

    2016-01-01

    The Green Bank Telescope is a 100-m aperture single-dish radio telescope. For high-frequency observations (above 100 GHz), it needs a tracking error below 1.5 arc sec rms. The present system has a tracking error of 1 arc sec rms for very low wind speeds of ≤1 m/s, which increases well above 1.5 arc sec for wind speeds above 4 m/s. Hence, improvements in the servo control system are needed to achieve pointing accuracy goals for high-frequency observations. As a first step toward this goal, it is necessary to evaluate the dynamic response of the present servo system and the telescope, which forms a large flexible structure. We derive the model of the telescope dynamics using finite element analysis data. This model is further tuned and validated using system identification experiments performed on the telescope. A reduced model is developed for controller design by using modes with the highest Hankel singular value for frequencies up to 2 Hz. We quantify the uncertainty in azimuth axis dynamics with a change in elevation angle by varying the zeros of the model. We discuss the effects of transient response, wind disturbances, and azimuth track joint disturbances on telescope tracking performance.

  5. Defining and Testing the Influence of Servo System Response on Machine Tool Compliance

    SciTech Connect

    Hopkins, D J

    2004-03-24

    Compliance can be defined as the measurement of displacement per unit of force applied e.g. nano-meters per Newton (m/N). Compliance is the reciprocal of stiffness. High stiffness means low compliance and visa versa. It is an important factor in machine tool characteristics because it reflects the ability of the machine axis to maintain a desired position as it encounters a force or torque. Static compliance is a measurement made with a constant force applied e.g. the average depth of cut. Dynamic compliance is a measurement made as a function of frequency, e.g. a fast too servo (FTS) that applies a varying cutting force or load, interrupted cuts and external disturbances such as ground vibrations or air conditioning induced forces on the machine. Compliance can be defined for both a linear and rotary axis of a machine tool. However, to properly define compliance for a rotary axis, the axis must allow a commanded angular position. Note that this excludes velocity only axes. In this paper, several factors are discussed that affect compliance but emphasis is placed on how the machine servo system plays a key role in compliance at low to mid frequency regions. The paper discusses several techniques for measuring compliance and provides examples of results from these measurements.

  6. Robust Image-Based Visual Servo Control of an Uncertain Missile Airframe

    NASA Astrophysics Data System (ADS)

    Aygun, Murat Tunca

    A nonlinear vision-based guidance law is presented for a missile-target scenario in the presence of model uncertainty and unknown target evasive maneuvers. To ease the readability of this thesis, detailed explanations of any relevant mathematical tools are provided, including stability definitions, the procedure of Lyapunov-based stability analysis, sliding mode control fundamentals, basics on visual servo control, and other basic nonlinear control tools. To develop the vision-based guidance law, projective geometric relationships are utilized to combine the image kinematics with the missile dynamics in an integrated visual dynamic system. The guidance law is designed using an image-based visual servo control method in conjunction with a sliding-mode control strategy, which is shown to achieve asymptotic target interception in the presence of the aforementioned uncertainties. A Lyapunov-based stability analysis is presented to prove the theoretical result, and numerical simulation results are provided to demonstrate the performance of the proposed robust controller for both stationary and non-stationary targets.

  7. Development of an autonomous biological cell manipulator with single-cell electroporation and visual servoing capabilities.

    PubMed

    Sakaki, Kelly; Dechev, Nikolai; Burke, Robert D; Park, Edward J

    2009-08-01

    Studies of single cells via microscopy and microinjection are a key component in research on gene functions, cancer, stem cells, and reproductive technology. As biomedical experiments become more complex, there is an urgent need to use robotic systems to improve cell manipulation and microinjection processes. Automation of these tasks using machine vision and visual servoing creates significant benefits for biomedical laboratories, including repeatability of experiments, higher throughput, and improved cell viability. This paper presents the development of a new 5-DOF robotic manipulator, designed for manipulating and microinjecting single cells. This biological cell manipulator (BCM) is capable of autonomous scanning of a cell culture followed by autonomous injection of cells using single-cell electroporation (SCE). SCE does not require piercing the cell membrane, thereby keeping the cell membrane fully intact. The BCM features high-precision 3-DOF translational and 2-DOF rotational motion, and a second z-axis allowing top-down placement of a micropipette tip onto the cell membrane for SCE. As a technical demonstration, the autonomous visual servoing and microinjection capabilities of the single-cell manipulator are experimentally shown using sea urchin eggs. PMID:19605307

  8. Tevatron AC dipole system

    SciTech Connect

    Miyamoto, R.; Kopp, S.E.; Jansson, A.; Syphers, M.J.; /Fermilab

    2007-06-01

    The AC dipole is an oscillating dipole magnet which can induce large amplitude oscillations without the emittance growth and decoherence. These properties make it a good tool to measure optics of a hadron synchrotron. The vertical AC dipole for the Tevatron is powered by an inexpensive high power audio amplifier since its operating frequency is approximately 20 kHz. The magnet is incorporated into a parallel resonant system to maximize the current. The use of a vertical pinger magnet which has been installed in the Tevatron made the cost relatively inexpensive. Recently, the initial system was upgraded with a more powerful amplifier and oscillation amplitudes up to 2-3{sigma} were achieved with the 980 GeV proton beam. This paper discusses details of the Tevatron AC dipole system and also shows its test results.

  9. Reactor coolant pump testing using motor current signatures analysis

    SciTech Connect

    Burstein, N.; Bellamy, J.

    1996-12-01

    This paper describes reactor coolant pump motor testing carried out at Florida Power Corporation`s Crystal River plant using Framatome Technologies` new EMPATH (Electric Motor Performance Analysis and Trending Hardware) system. EMPATH{trademark} uses an improved form of Motor Current Signature Analysis (MCSA), technology, originally developed at Oak Ridge National Laboratories, for detecting deterioration in the rotors of AC induction motors. Motor Current Signature Analysis (MCSA) is a monitoring tool for motor driven equipment that provides a non-intrusive means for detecting the presence of mechanical and electrical abnormalities in the motor and the driven equipment. The base technology was developed at the Oak Ridge National Laboratory as a means for determining the affects of aging and service wear specifically on motor-operated valves used in nuclear power plant safety systems, but it is applicable to a broad range of electric machinery. MCSA is based on the recognition that an electric motor (ac or dc) driving a mechanical load acts as an efficient and permanently available transducer by sensing mechanical load variations, large and small, long-term and rapid, and converting them into variations in the induced current generated in the motor windings. The motor current variations, resulting from changes in load caused by gears, pulleys, friction, bearings, and other conditions that may change over the life of the motor, are carried by the electrical cables powering the motor and are extracted at any convenient location along the motor lead. These variations modulate the 60 Hz carrier frequency and appear as sidebands in the spectral plot.

  10. The right {mu}P simplifies using induction motors to propel electric cars

    SciTech Connect

    Baum, J.; Berringer, K.

    1994-03-31

    In electric vehicles (EVs), AC induction motors can provide variable speed at low cost. The most common method for controlling induction motors uses a 3-phase AC voltage-source inverter with sine-wave PWM (pulse width modulation). Because the motor`s speed and acceleration depend on amplitude as well as frequency, the inverter must produce sine waves of variable voltage and frequency. The authors describe how a single microcontroller can provide such control functions while generating PWM waveforms in which the modulation is sinusoidal.

  11. Introducing AC inductive reactance with a power tool

    NASA Astrophysics Data System (ADS)

    Bryant, Wesley; Baker, Blane

    2016-09-01

    The concept of reactance in AC electrical circuits is often non-intuitive and difficult for students to grasp. In order to address this lack of conceptual understanding, classroom exercises compare the predicted resistance of a power tool, based on electrical specifications, to measured resistance. Once students discover that measured resistance is smaller than expected, they are asked to explain these observations using previously studied principles of magnetic induction. Exercises also introduce the notion of inductive reactance and impedance in AC circuits and, ultimately, determine self-inductance of the motor windings within the power tool.

  12. On the evolution of ac machines for spindle drive applications

    SciTech Connect

    Fratta, A.; Vagati, A.; Villata, F. )

    1992-10-01

    In the field of ac spindle drives, the induction motor is widely adopted. Synchronous solutions (reluctance, interior permanent magnets) are often suggested to overcome some drawbacks of the induction motor. This paper compares the different options by considering the machine torque-density and the inverter power size needed for a given constant-power speed range. It is shown that an axially laminated reluctance motor gives more torque density than the induction motor but nearly requires the same inverter size. By adding a proper quantity of permanent magnets, the inverter size can be greatly reduced. A comprehensive discussion is made on this subject, aiming to point out a design solution that is 'optimal' for the whole drive.

  13. Early augmented language intervention for children with developmental delays: potential secondary motor outcomes.

    PubMed

    Whitmore, Ani S; Romski, Mary Ann; Sevcik, Rose A

    2014-09-01

    This exploratory study examined the potential secondary outcome of an early augmented language intervention that incorporates speech-generating devices (SGD) on motor skill use for children with developmental delays. The data presented are from a longitudinal study by Romski and colleagues. Toddlers in the augmented language interventions were either required (Augmented Communication-Output; AC-O) or not required (Augmented Communication-Input; AC-I) to use the SGD to produce an augmented word. Three standardized assessments and five event-based coding schemes measured the participants' language abilities and motor skills. Toddlers in the AC-O intervention used more developmentally appropriate motor movements and became more accurate when using the SGD to communicate than toddlers in the AC-I intervention. AAC strategies, interventionist/parent support, motor learning opportunities, and physical feedback may all contribute to this secondary benefit of AAC interventions that use devices. PMID:25109299

  14. AC/RF Superconductivity

    SciTech Connect

    Ciovati, Gianluigi

    2015-02-01

    This contribution provides a brief introduction to AC/RF superconductivity, with an emphasis on application to accelerators. The topics covered include the surface impedance of normal conductors and superconductors, the residual resistance, the field dependence of the surface resistance, and the superheating field.

  15. AC solar cell

    SciTech Connect

    Schutten, H.P.; Benjamin, J.A.; Lade, R.W.

    1986-03-18

    An AC solar cell is described comprising: a pair of PN junction type solar cells connected in antiparallel between a pair of main terminals; and means for electrically directing light alternatingly without mechanical movement on the PN junctions to generate an alternating potential across the main terminals.

  16. AC 67 Launch Video

    NASA Technical Reports Server (NTRS)

    1987-01-01

    Live footage of the Unmanned Atlas Centaur (AC) 67 launch is presented on March 26, 1987 at the WESH television station in Florida. Lightning is shown after 49 seconds into the flight. The vehicle is totally destroyed due to a cloud-to-ground lightning flash.

  17. Opto-mechanical subsystem of a 10 micrometer wavelength receiver terminal. Waveguide laser local oscillator. Servo system

    NASA Technical Reports Server (NTRS)

    1975-01-01

    An engineering model opto-mechanical subsystem for a 10.6-micrometer laser heterodyne receiver is developed, and a CO2 waveguide local oscillator and servo electronics are provided for the receiver. Design goals are presented for the subsystems and overall package design is described. Thermal and mechanical distortion loading tests were performed and the results are included.

  18. Application of optimal control theory to the design of the NASA/JPL 70-meter antenna servos

    NASA Technical Reports Server (NTRS)

    Alvarez, L. S.; Nickerson, J.

    1989-01-01

    The application of Linear Quadratic Gaussian (LQG) techniques to the design of the 70-m axis servos is described. Linear quadratic optimal control and Kalman filter theory are reviewed, and model development and verification are discussed. Families of optimal controller and Kalman filter gain vectors were generated by varying weight parameters. Performance specifications were used to select final gain vectors.

  19. Design of a low-cost servo-actuated shaking table for simulating ground motions with strong vertical component

    NASA Astrophysics Data System (ADS)

    Tsolakis, Efstratios

    2014-10-01

    This article proposes a new set of configurationsfor the construction of a low cost servo-actuatedshake table with a wide range simulation ability, especially regarding ground motions with strong vertical components up to 3.86g and 1.62m acceleration and stroke respectively. Designing decision and challenges faced during the process are also presented.

  20. Fast or Slow, Either Head Can Start the Processive Run of Kinesin-2 KIF3AC.

    PubMed

    Zhang, Pengwei; Rayment, Ivan; Gilbert, Susan P

    2016-02-26

    Mammalian KIF3AC contains two distinct motor polypeptides and is best known for its role in organelle transport in neurons. Our recent studies showed that KIF3AC is as processive as conventional kinesin-1, suggesting that their ATPase mechanochemistry may be similar. However, the presence of two different motor polypeptides in KIF3AC implies that there must be a cellular advantage for the KIF3AC heterodimer. The hypothesis tested was whether there is an intrinsic bias within KIF3AC such that either KIF3A or KIF3C initiates the processive run. To pursue these experiments, a mechanistic approach was used to compare the pre-steady-state kinetics of KIF3AC to the kinetics of homodimeric KIF3AA and KIF3CC. The results indicate that microtubule collision at 11.4 μm(-1) s(-1) coupled with ADP release at 78 s(-1) are fast steps for homodimeric KIF3AA. In contrast, KIF3CC exhibits much slower microtubule association at 2.1 μm(-1) s(-1) and ADP release at 8 s(-1). For KIF3AC, microtubule association at 6.6 μm(-1) s(-1) and ADP release at 51 s(-1) are intermediate between the constants for KIF3AA and KIF3CC. These results indicate that either KIF3A or KIF3C can initiate the processive run. Surprisingly, the kinetics of the initial event of microtubule collision followed by ADP release for KIF3AC is not equivalent to 1:1 mixtures of KIF3AA plus KIF3CC homodimers at the same motor concentration. These results reveal that the intermolecular communication within the KIF3AC heterodimer modulates entry into the processive run regardless of whether the run is initiated by the KIF3A or KIF3C motor domain. PMID:26710851

  1. The international Solid Earth Virtual Research Observatory (iSERVO) institute seed project

    NASA Astrophysics Data System (ADS)

    Mora, P.; Donnellan, A.; Fox, G.; Pierce, M.; Matsu'Ura, M.; McLeod, D.; Yin, X.

    2003-12-01

    Numerical simulation models that capture the essential physics and dynamics of the solid earth system provide a critical means to probe the earth's complex system behaviour. The APEC Cooperation for Earthquake Simulation (ACES) was established to develop simulation models for the complete physics of earthquakes and related processes, to foster collaboration between complementary national programs, and to foster development of research infrastructure. Research by ACES participants is summarised in 3 special issues of PAGEOPH (2000, 2002, and in press). Solid earth simulator programs linked via ACES include a new 5 year program to establish a national facility in Australia (Australian Computational Earth Systems Simulator MNRF), USA programs being developed by NASA JPL in collaboration with science centers, and Japan's new Centre of Excellence in predictability of the evolution and variation of the multi-scale earth system. Plans are now commencing to establish the framework for an international institute for computational earth system simulation to maximise benefits of these international efforts. The institute will make extensive use of the World Wide Web, computational Grid technologies, and multi-tiered information architectures to allow simulation models and data to be manipulated by symbolic means in a way not previously possible. A seed iSERVO project is underway to illustrate the approach. It involves development of web based services and portals to enable different numerical simulation models contributed by Australia, Japan and USA to be run using several "standard" crustal fault system models (strike-slip, intraplate, and subduction). The iSERVO Grid is being constructed from Web services enhanced to be consistent with Grid Forum standards. The system uses distributed computing including high performance computers and distributed heterogeneous databases using OGSA interfaces. These are accessed with portals exploiting the new portlet standards. The iSERVO

  2. A PWM transistor inverter for an ac electric vehicle drive

    NASA Technical Reports Server (NTRS)

    Slicker, J. M.

    1981-01-01

    A prototype system consisting of closely integrated motor, inverter, and transaxle has been built in order to demonstrate the feasibility of a three-phase ac transistorized inverter for electric vehicle applications. The microprocessor-controlled inverter employs monolithic power transistors to drive an oil-cooled, three-phase induction traction motor at a peak output power of 30 kW from a 144 V battery pack. Transistor safe switching requirements are discussed, and a circuit is presented for recovering trapped snubber inductor energy at transistor turn-off.

  3. A Lead Angle Control for HB-Type Stepping Motor in the Constant Voltage Range

    NASA Astrophysics Data System (ADS)

    Okumatsu, Yoshihiro; Kawamura, Atsuo

    Stepping motors are generally used as a positioning servo in the OA (Office Automation) and FA (Factory Automation) system because the construction cost is very low and the construction of system is very easy. Since they are generally driven by an open loop controller, the response of stepping motors is oscillatory and it is possible to be out of drive. Therefore they are driven by a closed loop controller in the special system, which requires the high reliability and stability. The lead angle control is used as a closed loop controller of stepping motors because an applied voltage amplitude is not able to be controlled. However a closed loop control of stepping motors is hardly used at present. This paper presents the lead angle control based on the vector control in the constant voltage drive range for 2 phases HB type stepping motors. In the constant voltage range, since the HB type stepping motor is modeled as a surface permanent magnet motor, the motor torque is controlled by the q-axis current. The d-axis current is calculated by the voltage limit condition because of the constant voltage amplitude operation. The control performances are examined by the simulations and experimental results.

  4. Efficiency optimal control for AC drives with PWM inverters

    SciTech Connect

    Zach, F.C.; Ertl, H.

    1985-07-01

    For electrical drives using pulsewidth modulation (PWM) inverters and ac motors, methods for efficiency optimal control (EOC) have been developed. They are based on the most complete motor models, including such features as rotor skin effect. Furthermore, new solutions for selected harmonic elimination (SHE) are given. These new solutions come close to EOC. Also, it has been found that EOC solutions (although basically load-dependent as opposed to SHE) do not vary much with the motor used or the motor model applied. Even using a simple R-L series circuit as motor model does not change the solutions much. It is found that using the solutions gained from such a simple model is not more than two points off the real optimum based on a very complete motor model. (For this definition, the absolute harmonic loss minimum is given as zero points, the overall maximum as 100 points with a linear scale in between.) Therefore, one can use one EOC solution for all motors with sufficient accuracy, or, as second best solution, the new form of SHE. Therefore, the EOC solution can be judged load-independent. The implementation by microprocessor-based systems is as easy for other PWM methods. EOC for three and five switching angles per quarter period is discussed, as well as the new solutions for SHE for up to nine angles.

  5. Propulsion System Dynamic Modeling of the NASA Supersonic Concept Vehicle for AeroPropulsoServoElasticity

    NASA Technical Reports Server (NTRS)

    Kopasakis, George; Connolly, Joseph W.; Seiel, Jonathan

    2016-01-01

    A summary of the propulsion system modeling under NASA's High Speed Project (HSP) AeroPropulsoServoElasticity (APSE) task is provided with a focus on the propulsion system for the low-boom supersonic configuration developed by Lockheed Martin and referred to as the N+2 configuration. This summary includes details on the effort to date to develop computational models for the various propulsion system components. The objective of this paper is to summarize the model development effort in this task, while providing more detail in the modeling areas that have not been previously published. The purpose of the propulsion system modeling and the overall APSE effort is to develop an integrated dynamic vehicle model to conduct appropriate unsteady analysis of supersonic vehicle performance. This integrated APSE system model concept includes the propulsion system model, and the vehicle structural aerodynamics model. The development to date of such a preliminary integrated model will also be summarized in this report

  6. State feedback integral control for a rotary direct drive servo valve using a Lyapunov function approach.

    PubMed

    Yu, Jue; Zhuang, Jian; Yu, Dehong

    2015-01-01

    This paper concerns a state feedback integral control using a Lyapunov function approach for a rotary direct drive servo valve (RDDV) while considering parameter uncertainties. Modeling of this RDDV servovalve reveals that its mechanical performance is deeply influenced by friction torques and flow torques; however, these torques are uncertain and mutable due to the nature of fluid flow. To eliminate load resistance and to achieve satisfactory position responses, this paper develops a state feedback control that integrates an integral action and a Lyapunov function. The integral action is introduced to address the nonzero steady-state error; in particular, the Lyapunov function is employed to improve control robustness by adjusting the varying parameters within their value ranges. This new controller also has the advantages of simple structure and ease of implementation. Simulation and experimental results demonstrate that the proposed controller can achieve higher control accuracy and stronger robustness. PMID:25234140

  7. A switched energy saving position controller for variable-pressure electro-hydraulic servo systems.

    PubMed

    Tivay, Ali; Zareinejad, Mohammad; Rezaei, S Mehdi; Baghestan, Keivan

    2014-07-01

    The electro-hydraulic servo system (EHSS) demonstrates a relatively low level of efficiency compared to other available actuation methods. The objective of this paper is to increase this efficiency by introducing a variable supply pressure into the system and controlling this pressure during the task of position tracking. For this purpose, an EHSS structure with controllable supply pressure is proposed and its dynamic model is derived from the basic laws of physics. A switching control structure is then proposed to control both the supply pressure and the cylinder position at the same time, in a way that reduces the overall energy consumption of the system. The stability of the proposed switching control system is guaranteed by proof, and its performance is verified by experimental testing. PMID:24882668

  8. Investigation of creep by use of closed loop servo-hydraulic test system

    NASA Technical Reports Server (NTRS)

    Wu, H. C.; Yao, J. C.

    1981-01-01

    Creep tests were conducted by means of a closed loop servo-controlled materials test system. These tests are different from the conventional creep tests in that the strain history prior to creep may be carefully monitored. Tests were performed for aluminum alloy 6061-0 at 150 C and monitored by a PDP 11/04 minicomputer at a preset constant plastic-strain rate prehistory. The results show that the plastic-strain rate prior to creep plays a significant role in creep behavior. The endochronic theory of viscoplasticity was applied to describe the observed creep curves. The concepts of intrinsic time and strain rate sensitivity function are employed and modified according to the present observation.

  9. Tool decentration effect in slow tool servo diamond turning off-axis conic aspheric surface

    NASA Astrophysics Data System (ADS)

    Dai, Yi-fan; Guan, Chaoliang; Yin, Zi-qiang; Tie, Gui-peng; Chen, Hao-feng; Wang, Jian-min

    2010-10-01

    Off-axis conic aspheric mirrors are crucial components in some optical systems, such as three-mirror-anastigmatic telescopes (TMA). However, because of the swing limitation of lathe, off-axis aspheric mirrors are not easy to fabricate using a general-purpose diamond turning machine. This research demonstrates slow tool servo diamond turning process which allows fabricating off-axis conic aspheric mirrors on-axis. The figure error caused by tool centering error was studied on. An off-axis parabolic mirror was fabricated and actual machining data are discussed. The result proved that proposed approach is capable of fabricating copper off-axis parabolic mirror of 46mm diameter to a form accuracy of 0.736μm in PV error value.

  10. Fast tool servo system for online compensation of error motion on an ultraprecision lathe

    NASA Astrophysics Data System (ADS)

    Wang, Xiaohui; Sun, Tao

    2009-05-01

    In order to obtain high accuracy and a fine surface finish of large area workpiece, position control of machine tool has become the main concern to achieve high precision position control. In this system, diamond turning with a fast tool servo (FTS) driven by a piezoelectric actuator along with a capacitive displacement sensor was chosen as the fabrication method. A laser interferometer is implemented to measure the straightness error of the translational slide accurately. The detected error signals are compensated by the FTS during the cutting process. To achieve better tracking performance, proportional integral (PI) feed back control with a feed-forward predictor is implemented. Experimental results show that the FTS can effectively and successfully compensate the straightness errors of the X-axis translational slide of the miniature ultra-precision lathe.

  11. Freeform manufacturing of a progressive addition lens by use of a voice coil fast tool servo

    NASA Astrophysics Data System (ADS)

    Li, Yi Yu; Chen, Jiao Jie; Feng, Hai Hua; Li, Chaohong; Qu, Jia; Chen, Hao

    2014-08-01

    The back surface of progressive addition lens (PAL) is a non-rotationally symmetric freeform surface. The local radius varies progressively from the far zone to the near zone along the intermediate zone to give the addition power. Numerical simulation method is performed to calculate the discrete points on the freeform surface in polar coordinate and generate the data files containing the trajectory of diamond tool tip for surface machining. The fabrication of PAL is accomplished by using self-developed single-point diamond turning machine with voice coil fast tool servo. The polished freeform surface profile measured by a 3-axes coordinate measuring machine shows little deviation to the simulation result. Surface power and cylinder of the fabricated PAL is also measured for comparison with theoretical design.

  12. Parallel computation of level set method for 500 Hz visual servo control

    NASA Astrophysics Data System (ADS)

    Fei, Xianfeng; Igarashi, Yasunobu; Hashimoto, Koichi

    2008-11-01

    We propose a 2D microorganism tracking system using a parallel level set method and a column parallel vision system (CPV). This system keeps a single microorganism in the middle of the visual field under a microscope by visual servoing an automated stage. We propose a new energy function for the level set method. This function constrains an amount of light intensity inside the detected object contour to control the number of the detected objects. This algorithm is implemented in CPV system and computational time for each frame is 2 [ms], approximately. A tracking experiment for about 25 s is demonstrated. Also we demonstrate a single paramecium can be kept tracking even if other paramecia appear in the visual field and contact with the tracked paramecium.

  13. Propulsion System Dynamic Modeling of the NASA Supersonic Concept Vehicle for AeroPropulsoServoElasticity

    NASA Technical Reports Server (NTRS)

    Kopasakis, George; Connolly, Joseph W.; Seidel, Jonathan

    2014-01-01

    A summary of the propulsion system modeling under NASA's High Speed Project (HSP) AeroPropulsoServoElasticity (APSE) task is provided with a focus on the propulsion system for the lowboom supersonic configuration developed by Lockheed Martin and referred to as the N+2 configuration. This summary includes details on the effort to date to develop computational models for the various propulsion system components. The objective of this paper is to summarize the model development effort in this task, while providing more detail in the modeling areas that have not been previously published. The purpose of the propulsion system modeling and the overall APSE effort is to develop an integrated dynamic vehicle model to conduct appropriate unsteady analysis of supersonic vehicle performance. This integrated APSE system model concept includes the propulsion system model, and the vehicle structural-aerodynamics model. The development to date of such a preliminary integrated model will also be summarized in this report.

  14. Three-dimensional positioning control based on stereo microscopic visual servoing system

    NASA Astrophysics Data System (ADS)

    Sha, Xiaopeng; Li, Huiguang; Li, Wenchao; Wang, Shuai

    2015-01-01

    A stereo microscopic system as a high-precision visual feedback is widely used in the fields of micro-three-dimensional (3-D) measurement and micromanipulation tasks. A new stereo binocular visual servoing model based on a Greenough-type stereoscopic light microscope to solve the 3-D micropositioning problem is proposed. The new model contains no depth information, but the information at the left and right images is used to obtain the image Jacobian matrix. Visual information can be directly obtained from the 3-D space without measuring or estimating the depth information of the unknown points of the object via this new model. The new model can not only accurately and rapidly realize automatic control for a micromanipulation system, but also improve the system control performance. We design an image-based controller with consideration of the kinematics characteristics of a microrobot. Experimental results verify the validity of the model.

  15. Systemic approach to selecting H{sub {infinity}} weighting functions for DC servos

    SciTech Connect

    Ciann-Dong Yang; Hung-Chung Tai; Lee, C.C.

    1994-12-31

    This paper proposes an experimental solution for H{infinity} weighting functions selection by exploiting an experimental planning method which is widely used in quality control. Conducting matrix experiments via orthogonal array, several parameters in H{sub {infinity}} weighting functions can be determined efficiently so that the resulting controller is able to satisfy all design specifications. Of great importance, the proposed experimental method provides additional robust performance property to conventional H{sub {infinity}} control which can only prove robust stability and nominal performance. Velocity controller design of DC servomotors is demonstrated to show the remarkable robustness and superior servo performance provided by experimental H{sub {infinity}} design. A hardware environment is constructed to correlate the theoretical prediction and the measurement data. All specifications of robust stability and performance are validated by the experimental results.

  16. Incremental inverse kinematics based vision servo for autonomous robotic capture of non-cooperative space debris

    NASA Astrophysics Data System (ADS)

    Dong, Gangqi; Zhu, Z. H.

    2016-04-01

    This paper proposed a new incremental inverse kinematics based vision servo approach for robotic manipulators to capture a non-cooperative target autonomously. The target's pose and motion are estimated by a vision system using integrated photogrammetry and EKF algorithm. Based on the estimated pose and motion of the target, the instantaneous desired position of the end-effector is predicted by inverse kinematics and the robotic manipulator is moved incrementally from its current configuration subject to the joint speed limits. This approach effectively eliminates the multiple solutions in the inverse kinematics and increases the robustness of the control algorithm. The proposed approach is validated by a hardware-in-the-loop simulation, where the pose and motion of the non-cooperative target is estimated by a real vision system. The simulation results demonstrate the effectiveness and robustness of the proposed estimation approach for the target and the incremental control strategy for the robotic manipulator.

  17. Application of simple adaptive control to water hydraulic servo cylinder system

    NASA Astrophysics Data System (ADS)

    Ito, Kazuhisa; Yamada, Tsuyoshi; Ikeo, Shigeru; Takahashi, Koji

    2012-09-01

    Although conventional model reference adaptive control (MRAC) achieves good tracking performance for cylinder control, the controller structure is much more complicated and has less robustness to disturbance in real applications. This paper discusses the use of simple adaptive control (SAC) for positioning a water hydraulic servo cylinder system. Compared with MRAC, SAC has a simpler and lower order structure, i.e., higher feasibility. The control performance of SAC is examined and evaluated on a water hydraulic servo cylinder system. With the recent increased concerns over global environmental problems, the water hydraulic technique using pure tap water as a pressure medium has become a new drive source comparable to electric, oil hydraulic, and pneumatic drive systems. This technique is also preferred because of its high power density, high safety against fire hazards in production plants, and easy availability. However, the main problems for precise control in a water hydraulic system are steady state errors and overshoot due to its large friction torque and considerable leakage flow. MRAC has been already applied to compensate for these effects, and better control performances have been obtained. However, there have been no reports on the application of SAC for water hydraulics. To make clear the merits of SAC, the tracking control performance and robustness are discussed based on experimental results. SAC is confirmed to give better tracking performance compared with PI control, and a control precision comparable to MRAC (within 10 μm of the reference position) and higher robustness to parameter change, despite the simple controller. The research results ensure a wider application of simple adaptive control in real mechanical systems.

  18. AC power systems handbook

    SciTech Connect

    Whitaker, J.

    1991-01-01

    Transient disturbances are what headaches are made of. Whatever you call them-spikes, surges, are power bumps-they can take your equipment down and leave you with a complicated and expensive repair job. Protection against transient disturbances is a science that demands attention to detail. This book explains how the power distribution system works, what can go wrong with it, and how to protect a facility against abnormalities. system grounding and shielding are covered in detail. Each major method of transient protection is analyzed and its relative merits discussed. The book provides a complete look at the critical elements of the ac power system. Provides a complete look at the ac power system from generation to consumption. Discusses the mechanisms that produce transient disturbances and how to protect against them. Presents diagrams to facilitate system design. Covers new areas, such as the extent of the transient disturbance problem, transient protection options, and stand-by power systems.

  19. Gross motor control

    MedlinePlus

    Gross motor control is the ability to make large, general movements (such as waving an arm or lifting a ... Gross motor control is a milestone in the development of an infant. Infants develop gross motor control before they ...

  20. Multifocal Motor Neuropathy

    MedlinePlus

    ... Diversity Find People About NINDS NINDS Multifocal Motor Neuropathy Information Page Table of Contents (click to jump ... done? Clinical Trials Organizations What is Multifocal Motor Neuropathy? Multifocal motor neuropathy is a progressive muscle disorder ...

  1. Design and Control Implementation of AC Electric Power Steering System Test Bench*

    NASA Astrophysics Data System (ADS)

    Zhang, Weidong; Ai, Yibo

    Using AC motor is an important development trend of electric power steering system, and in this paper, we proposed a design of AC electric power steering system test bench. The paper introduced the bench structure, working principle and main components selection first, and then given the implementation scheme of test bench's three functions: simulation of the road resistance, power assistant control and data acquisition. The test results showed the feasibility of the test bench.

  2. Motor control for a brushless DC motor

    NASA Technical Reports Server (NTRS)

    Peterson, William J. (Inventor); Faulkner, Dennis T. (Inventor)

    1985-01-01

    This invention relates to a motor control system for a brushless DC motor having an inverter responsively coupled to the motor control system and in power transmitting relationship to the motor. The motor control system includes a motor rotor speed detecting unit that provides a pulsed waveform signal proportional to rotor speed. This pulsed waveform signal is delivered to the inverter to thereby cause an inverter fundamental current waveform output to the motor to be switched at a rate proportional to said rotor speed. In addition, the fundamental current waveform is also pulse width modulated at a rate proportional to the rotor speed. A fundamental current waveform phase advance circuit is controllingly coupled to the inverter. The phase advance circuit is coupled to receive the pulsed waveform signal from the motor rotor speed detecting unit and phase advance the pulsed waveform signal as a predetermined function of motor speed to thereby cause the fundamental current waveform to be advanced and thereby compensate for fundamental current waveform lag due to motor winding reactance which allows the motor to operate at higher speeds than the motor is rated while providing optimal torque and therefore increased efficiency.

  3. Characterization and snubbing of a bidirectional MCT in a resonant ac link converter

    NASA Technical Reports Server (NTRS)

    Lee, Tony; Elbuluk, Malik E.; Zinger, Donald S.

    1993-01-01

    The MOS-Controlled Thyristor (MCT) is emerging as a powerful switch that combines the better characteristics of existing power devices. A study of switching stresses on an MCT switch under zero voltage resonant switching is presented. The MCT is used as a bidirectional switch in an ac/ac pulse density modulated inverter for induction motor drive. Current and voltage spikes are observed and analyzed with variations in the timing of the switching. Different snubber circuit configurations are under investigation to minimize the effect of these transients. The results will be extended to study and test the MCT switching in a medium power (5 hp) induction motor drive.

  4. The faults and modified methods on the driving mechanism and the servo control system for the 25 m antenna of Shanghai Observatory.

    NASA Astrophysics Data System (ADS)

    Wang, Husheng

    This paper analyses principal faults on the driving mechanism and the servo control system for the 25 m radio telescope of Shanghai Observatory and gives some modified methods to prevent it from their reoccurring.

  5. The effect of 10 Hz transcranial alternating current stimulation (tACS) on corticomuscular coherence

    PubMed Central

    Wach, Claudia; Krause, Vanessa; Moliadze, Vera; Paulus, Walter; Schnitzler, Alfons; Pollok, Bettina

    2013-01-01

    Synchronous oscillatory activity at alpha (8–12 Hz), beta (13–30 Hz), and gamma (30–90 Hz) frequencies is assumed to play a key role for motor control. Corticomuscular coherence (CMC) represents an established measure of the pyramidal system's integrity. Transcranial alternating current stimulation (tACS) offers the possibility to modulate ongoing oscillatory activity. Behaviorally, 20 Hz tACS in healthy subjects has been shown to result in movement slowing. However, the neurophysiological changes underlying these effects are not entirely understood yet. The present study aimed at ascertaining the effects of tACS at 10 and 20 Hz in healthy subjects on CMC and local power of the primary sensorimotor cortex. Neuromagnetic activity was recorded during isometric contraction before and at two time points (2–10 min and 30–38 min) after tACS of the left primary motor cortex (M1), using a 306 channel whole head magnetoencephalography (MEG) system. Additionally, electromyography (EMG) of the right extensor digitorum communis (EDC) muscle was measured. TACS was applied at 10 and 20 Hz, respectively, for 10 min at 1 mA. Sham stimulation served as control condition. The data suggest that 10 Hz tACS significantly reduced low gamma band CMC during isometric contraction. This implies that tACS does not necessarily cause effects at stimulation frequency. Rather, the findings suggest cross-frequency interplay between alpha and low gamma band activity modulating functional interaction between motor cortex and muscle. PMID:24009573

  6. Dynamic modeling and characteristics analysis of a modal-independent linear ultrasonic motor.

    PubMed

    Li, Xiang; Yao, Zhiyuan; Zhou, Shengli; Lv, Qibao; Liu, Zhen

    2016-12-01

    In this paper, an integrated model is developed to analyze the fundamental characteristics of a modal-independent linear ultrasonic motor with double piezoelectric vibrators. The energy method is used to model the dynamics of the two piezoelectric vibrators. The interface forces are coupled into the dynamic equations of the two vibrators and the moving platform, forming a whole machine model of the motor. The behavior of the force transmission of the motor is analyzed via the resulting model to understand the drive mechanism. In particular, the relative contact length is proposed to describe the intermittent contact characteristic between the stator and the mover, and its role in evaluating motor performance is discussed. The relations between the output speed and various inputs to the motor and the start-stop transients of the motor are analyzed by numerical simulations, which are validated by experiments. Furthermore, the dead-zone behavior is predicted and clarified analytically using the proposed model, which is also observed in experiments. These results are useful for designing servo control scheme for the motor. PMID:27518427

  7. The Wild Aviolyt AC 1/Aviotab TA 2 - A computer controlled photogrammetric system

    NASA Astrophysics Data System (ADS)

    Kreiling, W.; Hasler, A.

    1980-10-01

    The Aviolyt AC 1/Aviotab TA 2 is designed to meet the highest requirements of photogrammetry in precision, flexibility, economy and reliability while also handling problems in the area of research and in the university. There are three basic components, an optical-mechanical unit with an integrated computer console, an electronics cabinet with the process computer, and the TA 2 digital-servo plotting table. The applications of the system are expanded by a wide range of accessories including a zoom system, plotting tools, and a magnetic tape unit among others. The computer software incorporates an operation system, a program library and a series of accessory programs that edit, interpret and debug. The system software is designed under principles of interactive operation, with several programs having individual logical unity.

  8. Passive adaptive control of chaos in synchronous reluctance motor

    NASA Astrophysics Data System (ADS)

    Wei, Du-Qu; Luo, Xiao-Shu

    2008-01-01

    The performance of synchronous reluctance motor (SynRM) degrades due to chaos when its systemic parameters fall into a certain area. To control the undesirable chaos in SynRM, a passive control law is presented in this paper, which transforms the chaotic SynRM into an equivalent passive system. It is proved that the equivalent system can be asymptotically stabilized at the set equilibrium point, namely, chaos in SynRM can be controlled. Moreover, in order to eliminate the influence of undeterministic parameters, an adaptive law is introduced into the designed controller. Computer simulation results show that the proposed controller is very effective and robust against the uncertainties in systemic parameters. The present study may help to maintain the secure operation of industrial servo drive system.

  9. Fabrication of servo-integrated template for 1.5 Teradot/inch2 bit patterned media with block copolymer directed assembly

    NASA Astrophysics Data System (ADS)

    Yang, XiaoMin; Xiao, Shuaigang; Hsu, Yautzong; Wang, HongYing; Hwu, Justin; Steiner, Philip; Wago, Koichi; Lee, Kim; Kuo, David

    2014-07-01

    Directed self-assembly (DSA) of block copolymers (BCPs) proves to be a viable solution for the ultrahigh density bit-patterned media (BPM) application. However, servo design integration is still extremely challenging since the servo layouts require more complex patterns than the simple arrays naturally achieved by the DSA process. We present an integration scheme to create BPM servo patterns by utilizing the BCP dot-array patterns. This proposed method is based on an imprint guided two-step DSA process, combined with conventional optical lithography to define two separate zones. Both the data zone and servo zone consist of self-assembled hexagonal dot arrays: a regular pattern in the data zone and an arbitrary pattern in the servo zone. This method was successfully used to fabricate a servo-integrated BPM template with an areal density of 1.5 Teradot/inch2 (Td/in.2) (Lo=22.3 nm). Using the fabricated quartz template, CoCrPt BPM media has been successfully patterned by nanoimprint lithography and subsequent ion-beam etching process on a 2.5 in. disk. Further, using patterned-in servo wedges on 1.5 Td/in.2 patterned CoCrPt media, we are able to close the servo control loop for track-following on a spin-stand test. The standard deviation of repeatable run-out over the full revolution is calculated to be about 4% of the 38.6 nm track pitch. This method is currently being used to fabricate a template at a much higher density of 3.2 Td/in.2 (Lo=15.2 nm).

  10. An AC drive system for a battery driven moped

    SciTech Connect

    Nandi, S.; Saha, S.; Sharon, M.; Sundersingh, V.P.

    1995-12-31

    A petrol driven moped is converted to an electric one by replacing the petrol engine by a three phase 1.5 HR, AC squirrel cage induction motor drive system. The motor voltage rating selected is 200 V to keep the DC boost voltage level to a reasonable value.f the power source used is a high energy density, 24 V, 110 Ah, Ni-Zn battery. A modified indirect current controlled step-up chopper as well as a standard push-pull DC-DC boost converter is studied for the boost scheme. A simple three phase quasi-square wave inverter is designed along with suitable protection for driving the motor. Successful trial test of the system has been conducted at the laboratory.

  11. Advanced ac powertrain for electric vehicles

    SciTech Connect

    Slicker, J.M.; Kalns, L.

    1985-01-01

    The design of an ac propulsion system for an electric vehicle includes a three-phase induction motor, transistorized PWM inverter/battery charger, microprocessor-based controller, and two-speed automatic transaxle. This system was built and installed in a Mercury Lynx test bed vehicle as part of a Department of Energy propulsion system development program. An integral part of the inverter is a 4-kw battery charger which utilizes one of the bridge transistors. The overall inverter strategy for this configuration is discussed. The function of the microprocessor-based controller is described. Typical test results of the total vehicle and each of its major components are given, including system efficiencies and test track performance results.

  12. HTS axial flux induction motor with analytic and FEA modeling

    NASA Astrophysics Data System (ADS)

    Li, S.; Fan, Y.; Fang, J.; Qin, W.; Lv, G.; Li, J. H.

    2013-11-01

    This paper presents a high-temperature superconductor (HTS) axial-flux induction motor, which can output levitation force and torque simultaneously. In order to analyze the character of the force, analytic method and finite element method are adopted to model the motor. To make sure the HTS can carry sufficiently large current and work well, the magnetic field distribution in HTS coil is calculated. An effective method to improve the critical current of HTS coil is presented. Then, AC losses in HTS windings in the motor are estimated and tested.

  13. AC propulsion system for an electric vehicle, phase 2

    NASA Technical Reports Server (NTRS)

    Slicker, J. M.

    1983-01-01

    A second-generation prototype ac propulsion system for a passenger electric vehicle was designed, fabricated, tested, installed in a modified Mercury Lynx vehicle and track tested at the Contractor's site. The system consisted of a Phase 2, 18.7 kw rated ac induction traction motor, a 192-volt, battery powered, pulse-width-modulated, transistorized inverter packaged for under rear seat installation, a 2-axis, 2-speed, automatically-shifted mechanical transaxle and a microprocessor-based powertrain/vehicle controller. A diagnostics computer to assist tuning and fault finding was fabricated. Dc-to-mechanical-system efficiency varied from 78% to 82% as axle speed/torque ranged from 159 rpm/788 nm to 65 rpm/328 nm. Track test efficiency results suggest that the ac system will be equal or superior to dc systems when driving urban cycles. Additional short-term work is being performed under a third contract phase (AC-3) to raise transaxle efficiency to predicted levels, and to improve starting and shifting characteristics. However, the long-term challenge to the system's viability remains inverter cost. A final report on the Phase 2 system, describing Phase 3 modifications, will be issued at the conclusion of AC-3.

  14. AC propulsion system for an electric vehicle, phase 2

    NASA Astrophysics Data System (ADS)

    Slicker, J. M.

    1983-06-01

    A second-generation prototype ac propulsion system for a passenger electric vehicle was designed, fabricated, tested, installed in a modified Mercury Lynx vehicle and track tested at the Contractor's site. The system consisted of a Phase 2, 18.7 kw rated ac induction traction motor, a 192-volt, battery powered, pulse-width-modulated, transistorized inverter packaged for under rear seat installation, a 2-axis, 2-speed, automatically-shifted mechanical transaxle and a microprocessor-based powertrain/vehicle controller. A diagnostics computer to assist tuning and fault finding was fabricated. Dc-to-mechanical-system efficiency varied from 78% to 82% as axle speed/torque ranged from 159 rpm/788 nm to 65 rpm/328 nm. Track test efficiency results suggest that the ac system will be equal or superior to dc systems when driving urban cycles. Additional short-term work is being performed under a third contract phase (AC-3) to raise transaxle efficiency to predicted levels, and to improve starting and shifting characteristics. However, the long-term challenge to the system's viability remains inverter cost. A final report on the Phase 2 system, describing Phase 3 modifications, will be issued at the conclusion of AC-3.

  15. Analysis of the computed torque drive method and comparison with conventional position servo for a computer-controlled manipulator

    NASA Technical Reports Server (NTRS)

    Markiewicz, B. R.

    1973-01-01

    A manipulator and its control system (modeled after a Stanford design) is being developed as part of an artificial intelligence project. This development includes an analytical study of the control system software. A comparison is presented of the computed torque method and the conventional position servo. No conclusion is made as to the perference of one system over the other, as it is dependent upon the application and the results of a sampled data analysis.

  16. Design of a H{sub {infinity}}-optimal servo compensator for the frequency and voltage control of power plants

    SciTech Connect

    Kiffmeier, U.; Unbehauen, H.

    1994-12-31

    This contribution investigates modern H{sub {infinity}} control concepts for frequency and voltage control of power plants. Based on a linearized model for a national grid H{sub {infinity}}-optimal servo compensators have been designed using a frequency domain approach recently published by the authors. As demonstrated in this paper, the multivariable H{sub {infinity}}-controller shows superior performance with respect to setting time and damping of oscillations compared to classical controllers of P/PID type.

  17. Dynamic modeling of the servovalves incorporated in the servo hydraulic system of the 70-meter DSN antennas

    NASA Technical Reports Server (NTRS)

    Bartos, R. D.

    1992-01-01

    As the pointing accuracy and service life requirements of the DSN 70 meter antenna increase, it is necessary to gain a more complete understanding of the servo hydraulic system in order to improve system designs to meet the new requirements. A mathematical model is developed for the servovalve incorporated into the hydraulic system of the 70 meter antenna and uses experimental data to verify the validity of the model and to identify the model parameters.

  18. Identification of /sup 233/Ac

    SciTech Connect

    Chu, Y.Y.; Zhou, M.L.

    1983-09-01

    We report in this paper identification of the new isotope /sup 233/Ac. Uranium targets were irradiated with 28 GeV protons; after rapid retrieval of the target and separation of actinium from thorium, /sup 233/Ac was allowed to decay into the known /sup 233/Th daughter. Exhaustive chemical purification was employed to permit the identification of /sup 233/Th via its characteristic ..gamma.. radiations. The half-life derived for /sup 233/Ac from several experiments is 2.3 +- 0.3 min. The production cross section for /sup 233/Ac is 100 ..mu..b.

  19. Acceleration amplitude-phase regulation for electro-hydraulic servo shaking table based on LMS adaptive filtering algorithm

    NASA Astrophysics Data System (ADS)

    Yao, Jianjun; Di, Duotao; Jiang, Guilin; Gao, Shuang

    2012-10-01

    Electro-hydraulic servo shaking table usually requires good control performance for acceleration replication. The poles of the electro-hydraulic servo shaking table are placed by three-variable control method using pole placement theory. The system frequency band is thus extended and the system stability is also enhanced. The phase delay and amplitude attenuation phenomenon occurs in electro-hydraulic servo shaking table corresponding to an acceleration sinusoidal input. The method for phase delay and amplitude attenuation elimination based on LMS adaptive filtering algorithm is proposed here. The task is accomplished by adjusting the weights using LMS adaptive filtering algorithm when there exits phase delay and amplitude attenuation between the input and its corresponding acceleration response. The reference input is weighted in such a way that it makes the system output track the input efficiently. The weighted input signal is inputted to the control system such that the output phase delay and amplitude attenuation are all cancelled. The above concept is used as a basis for the development of amplitude-phase regulation (APR) algorithm. The method does not need to estimate the system model and has good real-time performance. Experimental results demonstrate the efficiency and validity of the proposed APR control scheme.

  20. Turbofan Volume Dynamics Model for Investigations of Aero-Propulso-Servo-Elastic Effects in a Supersonic Commercial Transport

    NASA Technical Reports Server (NTRS)

    Connolly, Joseph W.; Kopasakis, George; Lemon, Kimberly A.

    2010-01-01

    A turbofan simulation has been developed for use in aero-propulso-servo-elastic coupling studies, on supersonic vehicles. A one-dimensional lumped volume approach is used whereby each component (fan, high-pressure compressor, combustor, etc.) is represented as a single volume using characteristic performance maps and conservation equations for continuity, momentum and energy. The simulation is developed in the MATLAB/SIMULINK (The MathWorks, Inc.) environment in order to facilitate controls development, and ease of integration with a future aero-servo-elastic vehicle model being developed at NASA Langley. The complete simulation demonstrated steady state results that closely match a proposed engine suitable for a supersonic business jet at the cruise condition. Preliminary investigation of the transient simulation revealed expected trends for fuel flow disturbances as well as upstream pressure disturbances. A framework for system identification enables development of linear models for controller design. Utilizing this framework, a transfer function modeling an upstream pressure disturbance s impacts on the engine speed is developed as an illustrative case of the system identification. This work will eventually enable an overall vehicle aero-propulso-servo-elastic model

  1. Real-Time Assessment of Autonomic Nerve Activity During Adaptive Servo-Ventilation Support or Waon Therapy.

    PubMed

    Imamura, Teruhiko; Kinugawa, Koichiro; Nitta, Daisuke; Komuro, Issei

    2016-07-27

    Adaptive servo-ventilation support and Waon therapy are recently developed non-pharmacological and noninvasive therapies for patients with heart failure refractory to guideline-directed medical therapy. These therapies decrease both preload and afterload, increase cardiac output, and appear to ameliorate autonomic nerve activity. However, the time course of autonomic nerve activity during these therapies remains unclear. We performed heart rate variability analysis using the MemCalc power spectral density method (MemCalc system; Suwa Trust Co, Tokyo) to assess autonomic nerve activity during adaptive servo-ventilation support and Waon therapy in two different cases and determined the time course of autonomic nerve activity during these therapies. During both therapies, we found a drastic increase in parasympathetic nerve activity and continuous suppression of sympathetic nerve activity. Heart rate variability analysis using the MemCalc method may be promising for the assessment of the efficacy of various treatments, including adaptive servo-ventilation support and Waon therapy, from the viewpoint of autonomic nerve activity. PMID:27385607

  2. AC resistance measuring instrument

    DOEpatents

    Hof, P.J.

    1983-10-04

    An auto-ranging AC resistance measuring instrument for remote measurement of the resistance of an electrical device or circuit connected to the instrument includes a signal generator which generates an AC excitation signal for application to a load, including the device and the transmission line, a monitoring circuit which provides a digitally encoded signal representing the voltage across the load, and a microprocessor which operates under program control to provide an auto-ranging function by which range resistance is connected in circuit with the load to limit the load voltage to an acceptable range for the instrument, and an auto-compensating function by which compensating capacitance is connected in shunt with the range resistance to compensate for the effects of line capacitance. After the auto-ranging and auto-compensation functions are complete, the microprocessor calculates the resistance of the load from the selected range resistance, the excitation signal, and the load voltage signal, and displays of the measured resistance on a digital display of the instrument. 8 figs.

  3. AC Resistance measuring instrument

    DOEpatents

    Hof, Peter J.

    1983-01-01

    An auto-ranging AC resistance measuring instrument for remote measurement of the resistance of an electrical device or circuit connected to the instrument includes a signal generator which generates an AC excitation signal for application to a load, including the device and the transmission line, a monitoring circuit which provides a digitally encoded signal representing the voltage across the load, and a microprocessor which operates under program control to provide an auto-ranging function by which range resistance is connected in circuit with the load to limit the load voltage to an acceptable range for the instrument, and an auto-compensating function by which compensating capacitance is connected in shunt with the range resistance to compensate for the effects of line capacitance. After the auto-ranging and auto-compensation functions are complete, the microprocessor calculates the resistance of the load from the selected range resistance, the excitation signal, and the load voltage signal, and displays of the measured resistance on a digital display of the instrument.

  4. An iterative model-based cogging compensator for the Green Bank Telescope servo system

    NASA Astrophysics Data System (ADS)

    Franke, Timothy; Weadon, Timothy; Ford, John; Garcia-Sanz, Mario

    2014-07-01

    This paper outlines an anti-cogging methodology and summarizes the current state of motor cogging cancellation on the Green Bank Telescope (GBT). An iterative, model-based algorithm is developed for finding the anticogging signal which yields rapid convergence. This method fills a gap in present methodologies in that it can serve as a drop-in cogging solution which operates in the presence of unknown structural dynamics as well as with an existing feedback controller. The algorithm is described and demonstrated on a 40 HP DC brushed motor test bed and also on the GBT's elevation axis motors. Results and implementation experience from deploying the algorithm on a motor test bed and on the GBT are discussed.

  5. Evaluation of the Argonne National Laboratory servo-controlled calorimeter system

    SciTech Connect

    Foster, L.A.

    1997-01-01

    The control system of a replacement mode, twin-bridge, water-bath calorimeter originally built by Mound EG&G Applied Technologies was modified by Argonne National Laboratory. The calorimeter was upgraded with a PC-based computer control and data acquisition system. The system was redesigned to operate in a servo-control mode, and a preheater was constructed to allow pre-equilibration of samples. The instrument was sent to the Plutonium Facility at Los Alamos National Laboratory for testing and evaluation of its performance in the field using heat source standards and plutonium process materials. The important parameters for calorimeter operation necessary to satisfy the nuclear materials control and accountability requirements of the Plutonium Facility were evaluated over a period of several months. These parameters include calorimeter stability, measurement precision and accuracy, and average measurement time. The observed measurement precision and accuracy were found to be acceptable for most accountability measurements, although they were slightly larger than the values for calorimeters in routine use at the Plutonium Facility. Average measurement times were significantly shorter than measurement times for identical items in the Plutonium Facility calorimeters. Unexplained shifts in the baseline measurements were observed on numerous occasions. These shifts could lead to substantial measurement errors if they are not very carefully monitored by the operating facility. Detailed results of the experimental evaluation are presented in this report.

  6. A TSR Visual Servoing System Based on a Novel Dynamic Template Matching Method †

    PubMed Central

    Cai, Jia; Huang, Panfeng; Zhang, Bin; Wang, Dongke

    2015-01-01

    The so-called Tethered Space Robot (TSR) is a novel active space debris removal system. To solve its problem of non-cooperative target recognition during short-distance rendezvous events, this paper presents a framework for a real-time visual servoing system using non-calibrated monocular-CMOS (Complementary Metal Oxide Semiconductor). When a small template is used for matching with a large scene, it always leads to mismatches, so a novel template matching algorithm to solve the problem is presented. Firstly, the novel matching algorithm uses a hollow annulus structure according to a FAST (Features from Accelerated Segment) algorithm and makes the method be rotation-invariant. Furthermore, the accumulative deviation can be decreased by the hollow structure. The matching function is composed of grey and gradient differences between template and object image, which help it reduce the effects of illumination and noises. Then, a dynamic template update strategy is designed to avoid tracking failures brought about by wrong matching or occlusion. Finally, the system synthesizes the least square integrated predictor, realizing tracking online in complex circumstances. The results of ground experiments show that the proposed algorithm can decrease the need for sophisticated computation and improves matching accuracy. PMID:26703609

  7. An energy-saving nonlinear position control strategy for electro-hydraulic servo systems.

    PubMed

    Baghestan, Keivan; Rezaei, Seyed Mehdi; Talebi, Heidar Ali; Zareinejad, Mohammad

    2015-11-01

    The electro-hydraulic servo system (EHSS) demonstrates numerous advantages in size and performance compared to other actuation methods. Oftentimes, its utilization in industrial and machinery settings is limited by its inferior efficiency. In this paper, a nonlinear backstepping control algorithm with an energy-saving approach is proposed for position control in the EHSS. To achieve improved efficiency, two control valves including a proportional directional valve (PDV) and a proportional relief valve (PRV) are used to achieve the control objectives. To design the control algorithm, the state space model equations of the system are transformed to their normal form and the control law through the PDV is designed using a backstepping approach for position tracking. Then, another nonlinear set of laws is derived to achieve energy-saving through the PRV input. This control design method, based on the normal form representation, imposes internal dynamics on the closed-loop system. The stability of the internal dynamics is analyzed in special cases of operation. Experimental results verify that both tracking and energy-saving objectives are satisfied for the closed-loop system. PMID:26520165

  8. Disturbance torque rejection properties of the NASA/JPL 70-meter antenna axis servos

    NASA Technical Reports Server (NTRS)

    Hill, R. E.

    1989-01-01

    Analytic methods for evaluating pointing errors caused by external disturbance torques are developed and applied to determine the effects of representative values of wind and friction torque. The expressions relating pointing errors to disturbance torques are shown to be strongly dependent upon the state estimator parameters, as well as upon the state feedback gain and the flow versus pressure characteristics of the hydraulic system. Under certain conditions, when control is derived from an uncorrected estimate of integral position error, the desired type 2 servo properties are not realized and finite steady-state position errors result. Methods for reducing these errors to negligible proportions through the proper selection of control gain and estimator correction parameters are demonstrated. The steady-state error produced by a disturbance torque is found to be directly proportional to the hydraulic internal leakage. This property can be exploited to provide a convenient method of determining system leakage from field measurements of estimator error, axis rate, and hydraulic differential pressure.

  9. Vibration Control of a Microactuator for Servo Application by Active Damping

    NASA Astrophysics Data System (ADS)

    Hirano, Toshiki

    2003-03-01

    When using a microactuator for servo applications that require high position accuracy and fast response, one of the typical issues is the microactuator’s large amplitude resonance. This resonance occurs because most microactuators use springs to support their moving masses, combined with little damping effects that are due mainly to the viscosity of the air. To solve this problem, we propose the use of a capacitive position sensing method, combined with a high aspect ratio, highly area-efficient, and high structural-height microactuator that can obtain a large capacitance change for a given stroke. This combination does not require a very complex or difficult implementation such as an on-chip preamplifier or a sophisticated filter. A microactuator was manufactured and combined with a relatively simple capacitive sensing circuit made of discrete components such as a spectrum analyzer and amplifier. Even with this relatively crude setup, we were able to obtain a high quality capacitive position signal. The controller was designed and the active damping control loop was successfully closed. The performance was measured by experiment, and demonstrated that the active damping was extremely effective in suppressing oscillations caused by external force disturbances, and in settling to the new position for a step input.

  10. A Visual Servoing-Based Method for ProCam Systems Calibration

    PubMed Central

    Berry, Francois; Aider, Omar Ait; Mosnier, Jeremie

    2013-01-01

    Projector-camera systems are currently used in a wide field of applications, such as 3D reconstruction and augmented reality, and can provide accurate measurements, depending on the configuration and calibration. Frequently, the calibration task is divided into two steps: camera calibration followed by projector calibration. The latter still poses certain problems that are not easy to solve, such as the difficulty in obtaining a set of 2D–3D points to compute the projection matrix between the projector and the world. Existing methods are either not sufficiently accurate or not flexible. We propose an easy and automatic method to calibrate such systems that consists in projecting a calibration pattern and superimposing it automatically on a known printed pattern. The projected pattern is provided by a virtual camera observing a virtual pattern in an OpenGL model. The projector displays what the virtual camera visualizes. Thus, the projected pattern can be controlled and superimposed on the printed one with the aid of visual servoing. Our experimental results compare favorably with those of other methods considering both usability and accuracy. PMID:24084121

  11. Fabrication of continuous diffractive optical elements using a fast tool servo diamond turning process

    NASA Astrophysics Data System (ADS)

    Zhou, Jingbo; Li, Lei; Naples, Neil; Sun, Tao; Yi, Allen Y.

    2013-07-01

    Continuous diffractive optical elements (CDOEs) can be used for laser-beam reshaping, pattern generation and can help reduce large angle scattering. Lithography, the method for the production of binary diffractive surfaces, is not suitable for fabrication of CDOEs. Diamond turning using fast tool servo, on the other hand, is a non-cleanroom method for generating continuous microstructures with high precision and efficiency. In this paper, an algorithm for designing CDOEs is introduced. The moving least-squares (MLS) method is then used to obtain the local fitting equation of the diffractive surface. Based on the MLS fitting equation, the selection of diamond cutting tool geometries (including the tool nose radius, rake angle and clearance angle) is discussed and a tool nose radius compensation algorithm is included. This algorithm is a general method for the diamond turning of complex surfaces that can be represented by a point cloud. Surface measurements and diffractive patterns generated on test samples have shown that continuous diffractive surfaces were successfully machined. In the future, CDOEs can be machined on an optical mold surface for high-volume industrial production using methods such as injection molding.

  12. Towards an Aero-Propulso-Servo-Elasticity Analysis of a Commercial Supersonic Transport

    NASA Technical Reports Server (NTRS)

    Connolly, Joseph W.; Kopasakis, George; Chwalowski, Pawel; Sanetrik, Mark D.; Carlson, Jan-Renee; Silva, Walt A.; McNamara, Jack

    2016-01-01

    This paper covers the development of an aero-propulso-servo-elastic (APSE) model using computational fluid dynamics (CFD) and linear structural deformations. The APSE model provides the integration of the following two previously developed nonlinear dynamic simulations: a variable cycle turbofan engine and an elastic supersonic commercial transport vehicle. The primary focus of this study is to provide a means to include relevant dynamics of a turbomachinery propulsion system into the aeroelastic studies conducted during a vehicle design, which have historically neglected propulsion effects. A high fidelity CFD tool is used here for the integration platform. The elastic vehicle neglecting the propulsion system serves as a comparison of traditional approaches to the APSE results. An overview of the methodology is presented for integrating the propulsion system and elastic vehicle. Static aeroelastic analysis comparisons between the traditional and developed APSE models for a wing tip detection indicate that the propulsion system impact on the vehicle elastic response could increase the detection by approximately ten percent.

  13. State transformation-based dynamic visual servoing for an unmanned aerial vehicle

    NASA Astrophysics Data System (ADS)

    Xie, Hui; Lynch, Alan F.

    2016-05-01

    In this paper, we propose a visual servoing control for a quadrotor unmanned aerial vehicle (UAV) which is based on a state transformation technique. The UAV is equipped with a single downwards facing camera, and the motion control objective is the regulation of relative displacement and yaw to a stationary visual target located on the ground. The state transformation is defined by a system of partial differential equations (PDEs) which eliminate roll and pitch rate dependence in the transformed image feature kinematics. A method for computing the general solutions of these PDEs is given, and we show a particular solution reduces to an established virtual camera approach. We treat point and line cases and introduce image moment features defined in the virtual camera image plane. Robustness of the control design is improved by accounting for attitude measurement bias, and uncertainty in thrust gain, mass, and image feature depth. The asymptotic stability of the closed-loop is proven. The method is based on a simple proportional-integral-derivative (PID) structure which can be readily implemented on-board. Experimental results show improved performance relative to previous work.

  14. Design and control of a fast tool servo used in noncircular piston turning process

    NASA Astrophysics Data System (ADS)

    Wang, Haifeng; Yang, Shuyan

    2013-03-01

    Noncircular pistons are becoming more and more popular in the automotive industry. The challenge of machining this kind of pistons (e.g., middle-convex and varying ellipse piston (MCVEP)), lies in the rigorous demand of the cutting feed mechanism for large force generation, high stiffness, fast response, long stroke and high accuracy. The conventional processing methods cannot meet the challenge so a new piezoelectric actuator (PEA) based fast tool servo (FTS) mechanism was developed to incorporate additional functions to a general CNC system that will facilitate the execution of MCVEP turning. Since the desired tool trajectories are approximately periodic signals in MCVEP turning, and the repetitive control can achieve asymptotic tracking and disturbance rejection of periodic signals, a plug-in repetitive control is designed to be added on the conventional PID controller. In the experiments, the designed prototype was used to machine a MCVEP for the gasoline engine, which was equipped with the PEA-based FTS system, as well as the plug-in repetitive controller. The machining test validated the effective of the designed noncircular turning system.

  15. An Observer-Based Friction Compensation Technique for Positioning Control of a Pneumatic Servo System

    NASA Astrophysics Data System (ADS)

    Kosaki, Takahiro; Sano, Manabu

    This paper presents a technique to cope with undesirable frictional effects in positioning control of a pneumatic actuator. This technique is based on an observer for estimating the dynamically varying friction force on-line. The observer is derived from an available nonlinear observer for Coulomb friction by modifying it to fit the pneumatic actuator and to enhance its estimation ability. Our pneumatic servo system for positioning consists of an inner pressure control loop, an outer position control loop, the friction observer, and a velocity observer. In this system, the friction force is compensated by adjusting a desired pressure value sent from the outer loop to the inner loop according to the friction observer output. Experimental comparisons with a conventional control system using friction compensation by means of accelerometer information feedback were carried out and show that our system works with almost the same high positioning accuracy as the conventional system, despite having neither an accelerometer nor a velocity sensor, and is more advantageous from the perspective of cost performance.

  16. Fracture tolerance analysis of the solid rocket booster servo-actuator for the space shuttle

    SciTech Connect

    Smith, S.H.; Ghadiali, N.D.; Zahoor, A.; Wilson, M.R.

    1982-01-01

    The results of an evaluation of the fracture tolerance of three components of the thrust vector control servo-actuator for the solid rocket booster of the space shuttle are described. These components were considered as being potentially fracture critical and therefore having the potential to fall short of a desired service life of 80 missions (that is, a service life factor of 4.0 on a basic service life of 20 missions). Detailed stress analysis of the rod end, cylinder, and feedback link components was accomplished by three-dimensional finite-element stress analysis methods. A dynamic structural model of the feedback system was used to determine the dynamic inertia loads and reactions to apply to the finite-element model of the feedback link. Twenty mission stress spectra consisting of lift-off, boost, re-entry, and water impact mission segments were developed for each component based on dynamic loadings. Most components were determined to have the potential of reaching a service life of 80 missions or service life factor of 4.0. 22 refs.

  17. A TSR Visual Servoing System Based on a Novel Dynamic Template Matching Method.

    PubMed

    Cai, Jia; Huang, Panfeng; Zhang, Bin; Wang, Dongke

    2015-01-01

    The so-called Tethered Space Robot (TSR) is a novel active space debris removal system. To solve its problem of non-cooperative target recognition during short-distance rendezvous events, this paper presents a framework for a real-time visual servoing system using non-calibrated monocular-CMOS (Complementary Metal Oxide Semiconductor). When a small template is used for matching with a large scene, it always leads to mismatches, so a novel template matching algorithm to solve the problem is presented. Firstly, the novel matching algorithm uses a hollow annulus structure according to a FAST (Features from Accelerated Segment) algorithm and makes the method be rotation-invariant. Furthermore, the accumulative deviation can be decreased by the hollow structure. The matching function is composed of grey and gradient differences between template and object image, which help it reduce the effects of illumination and noises. Then, a dynamic template update strategy is designed to avoid tracking failures brought about by wrong matching or occlusion. Finally, the system synthesizes the least square integrated predictor, realizing tracking online in complex circumstances. The results of ground experiments show that the proposed algorithm can decrease the need for sophisticated computation and improves matching accuracy. PMID:26703609

  18. Propulsion System Dynamic Modeling for the NASA Supersonic Concept Vehicle: AeroPropulsoServoElasticity

    NASA Technical Reports Server (NTRS)

    Kopasakis, George; Connolly, Joseph; Seidel, Jonathan

    2014-01-01

    A summary of the propulsion system modeling under NASA's High Speed Project (HSP) AeroPropulsoServoElasticity (APSE) task is provided with a focus on the propulsion system for the low-boom supersonic configuration developed by Lockheed Martin and referred to as the N+2 configuration. This summary includes details on the effort to date to develop computational models for the various propulsion system components. The objective of this paper is to summarize the model development effort in this task, while providing more detail in the modeling areas that have not been previously published. The purpose of the propulsion system modeling and the overall APSE effort is to develop an integrated dynamic vehicle model to conduct appropriate unsteady analysis of supersonic vehicle performance. This integrated APSE system model concept includes the propulsion system model, and the vehicle structural-aerodynamics model. The development to date of such a preliminary integrated model will also be summarized in this report.propulsion system dynamics, the structural dynamics, and aerodynamics.

  19. Nonlinear modeling and predictive functional control of Hammerstein system with application to the turntable servo system

    NASA Astrophysics Data System (ADS)

    Zhang, Qian; Wang, Qunjing; Li, Guoli

    2016-05-01

    This article deals with the identification of nonlinear model and Nonlinear Predictive Functional Controller (NPFC) design based on the Hammerstein structure for the turntable servo system. As a mechanism with multi-mass rotational system, nonlinearities significantly influence the system operation, especially when the turntable is in the states of zero-crossing distortion or rapid acceleration/deceleration, etc. The field data from identification experiments are processed by Comprehensive Learning Particle Swarm Optimization (CLPSO). As a result, Hammerstein model can be derived to describe the input-output relationship globally, considering all the linear and nonlinear factors of the turntable system. Cross validation results demonstrate good correspondence between the real equipment and the identified model. In the second part of this manuscript, a nonlinear control strategy based on the genetic algorithm and predictive control is developed. The global nonlinear predictive controller is carried out by two steps: (i) build the linear predictive functional controller with state space equations for the linear subsystem of Hammerstein model, and (ii) optimize the global control variable by minimizing the cost function through genetic algorithm. On the basis of distinguish model for turntable and the effectiveness of NPFC, the good performance of tracking ability is achieved in the simulation results.

  20. Visual servo walking control for humanoids with finite-time convergence and smooth robot velocities

    NASA Astrophysics Data System (ADS)

    Delfin, Josafat; Becerra, Hector M.; Arechavaleta, Gustavo

    2016-07-01

    In this paper, we address the problem of humanoid locomotion guided from information of a monocular camera. The goal of the robot is to reach a desired location defined in terms of a target image, i.e., a positioning task. The proposed approach allows us to introduce a desired time to complete the positioning task, which is advantageous in contrast to the classical exponential convergence. In particular, finite-time convergence is achieved while generating smooth robot velocities and considering the omnidirectional waking capability of the robot. In addition, we propose a hierarchical task-based control scheme, which can simultaneously handle the visual positioning and the obstacle avoidance tasks without affecting the desired time of convergence. The controller is able to activate or inactivate the obstacle avoidance task without generating discontinuous velocity references while the humanoid is walking. Stability of the closed loop for the two task-based control is demonstrated theoretically even during the transitions between the tasks. The proposed approach is generic in the sense that different visual control schemes are supported. We evaluate a homography-based visual servoing for position-based and image-based modalities, as well as for eye-in-hand and eye-to-hand configurations. The experimental evaluation is performed with the humanoid robot NAO.

  1. Optimal design of a main driving mechanism for servo punch press based on performance atlases

    NASA Astrophysics Data System (ADS)

    Zhou, Yanhua; Xie, Fugui; Liu, Xinjun

    2013-09-01

    The servomotor drive turret punch press is attracting more attentions and being developed more intensively due to the advantages of high speed, high accuracy, high flexibility, high productivity, low noise, cleaning and energy saving. To effectively improve the performance and lower the cost, it is necessary to develop new mechanisms and establish corresponding optimal design method with uniform performance indices. A new patented main driving mechanism and a new optimal design method are proposed. In the optimal design, the performance indices, i.e., the local motion/force transmission indices ITI, OTI, good transmission workspace good transmission workspace(GTW) and the global transmission indices GTIs are defined. The non-dimensional normalization method is used to get all feasible solutions in dimensional synthesis. Thereafter, the performance atlases, which can present all possible design solutions, are depicted. As a result, the feasible solution of the mechanism with good motion/force transmission performance is obtained. And the solution can be flexibly adjusted by designer according to the practical design requirements. The proposed mechanism is original, and the presented design method provides a feasible solution to the optimal design of the main driving mechanism for servo punch press.

  2. Cooling Floor AC Systems

    NASA Astrophysics Data System (ADS)

    Jun, Lu; Hao, Ding; Hong, Zhang; Ce, Gao Dian

    The present HVAC equipments for the residential buildings in the Hot-summer-and-Cold-winter climate region are still at a high energy consuming level. So that the high efficiency HVAC system is an urgently need for achieving the preset government energy saving goal. With its advantage of highly sanitary, highly comfortable and uniform of temperature field, the hot-water resource floor radiation heating system has been widely accepted. This paper has put forward a new way in air-conditioning, which combines the fresh-air supply unit and such floor radiation system for the dehumidification and cooling in summer or heating in winter. By analyze its advantages and limitations, we found that this so called Cooling/ Heating Floor AC System can improve the IAQ of residential building while keep high efficiency quality. We also recommend a methodology for the HVAC system designing, which will ensure the reduction of energy cost of users.

  3. Digital ac monitor

    DOEpatents

    Hart, George W.; Kern, Jr., Edward C.

    1987-06-09

    An apparatus and method is provided for monitoring a plurality of analog ac circuits by sampling the voltage and current waveform in each circuit at predetermined intervals, converting the analog current and voltage samples to digital format, storing the digitized current and voltage samples and using the stored digitized current and voltage samples to calculate a variety of electrical parameters; some of which are derived from the stored samples. The non-derived quantities are repeatedly calculated and stored over many separate cycles then averaged. The derived quantities are then calculated at the end of an averaging period. This produces a more accurate reading, especially when averaging over a period in which the power varies over a wide dynamic range. Frequency is measured by timing three cycles of the voltage waveform using the upward zero crossover point as a starting point for a digital timer.

  4. Thermionic triode generates ac power

    NASA Technical Reports Server (NTRS)

    Kniazzeh, A. G. F.; Scharz, F. C.

    1970-01-01

    Electrostatic grid controls conduction cycle of thermionic diode to convert low dc output voltages to high ac power without undesirable power loss. An ac voltage applied to the grid of this new thermionic triode enables it to convert heat directly into high voltage electrical power.

  5. Automated ac galvanomagnetic measurement system

    NASA Technical Reports Server (NTRS)

    Szofran, F. R.; Espy, P. N.

    1985-01-01

    An automated, ac galvanomagnetic measurement system is described. Hall or van der Pauw measurements in the temperature range 10-300 K can be made at a preselected magnetic field without operator attendance. Procedures to validate sample installation and correct operation of other system functions, such as magnetic field and thermometry, are included. Advantages of ac measurements are discussed.

  6. Linear motor drive system for continuous-path closed-loop position control of an object

    DOEpatents

    Barkman, William E.

    1980-01-01

    A precision numerical controlled servo-positioning system is provided for continuous closed-loop position control of a machine slide or platform driven by a linear-induction motor. The system utilizes filtered velocity feedback to provide system stability required to operate with a system gain of 100 inches/minute/0.001 inch of following error. The filtered velocity feedback signal is derived from the position output signals of a laser interferometer utilized to monitor the movement of the slide. Air-bearing slides mounted to a stable support are utilized to minimize friction and small irregularities in the slideway which would tend to introduce positioning errors. A microprocessor is programmed to read command and feedback information and converts this information into the system following error signal. This error signal is summed with the negative filtered velocity feedback signal at the input of a servo amplifier whose output serves as the drive power signal to the linear motor position control coil.

  7. Condition monitoring of machinery using motor current signature analysis

    SciTech Connect

    Kryter, R.C.; Haynes, H.D.

    1989-01-01

    Motor current signature analysis (MCSA) is a powerful monitoring tool for motor-driven equipment that provides a nonintrusive means for detecting the presence of mechanical and electrical abnormalities in the motor and the driven equipment, including altered conditions in the process ''downstream'' of the motor-driven equipment. It was developed at the Oak Ridge National Laboratory as a means for determining the effects of aging and service wear systems, but it is applicable to a broad range of machinery. MCSA is based on the recognition that an electric motor (ac or dc) driving a mechanical load acts as an efficient and permanently available transducer by sensing mechanical load variations, large and small, long-term and rapid, and converting them into variations in the induced current generated in the motor windings. These motor current variations are carried by the electrical cables processes as desired. Motor current signatures, obtained in both time and over time to provide early indication of degradation. Successful applications of MCSA technology (patent applied for) include not only motor-operated valves but also pumps of various designs, blowers, and air conditioning systems. Examples are presented briefly, and speculation regarding the applicability of MCSA to a broader range of equipment monitoring and production line testing is also given. 1 ref., 13 figs.

  8. Assessment of US electric vehicle programs with ac powertrains

    SciTech Connect

    Kevala, R.J. . Transportation Consulting Div.)

    1990-02-01

    AC powertrain technology is a promising approach to improving the performance of electric vehicles. Four major programs are now under way in the United States to develop ac powertrains: the Ford/General Electric single-shaft electric propulsion system (ETX-II), the Eaton dual-shaft electric propulsion system (DSEP), the Jet Propulsion Laboratories (JPL) integrated ac motor drive and recharge system, and the Massachusetts Institute of Technology (MIT) variable reluctance motor (VRM) drive. The JPL program is sponsored by EPRI; the other three programs are funded by the US Department of Energy. This preliminary assessment of the four powertrain programs focuses on potential performance, costs, safety, and commercial feasibility. Interviews with program personnel were supplemented by computer simulations of electric vehicle performance using the four systems. Each of the four powertrains appears superior to standard dc powertrain technology in terms of performance and weight. The powertrain technologies studied in this assessment are at varying degrees of technological maturity. One or more of the systems may be ready for incorporation into an advanced electric vehicle during the early 1990s. Each individual report will have a separate abstract. 5 refs., 37 figs., 29 tabs.

  9. Forward and reverse control system for induction motors

    DOEpatents

    Wright, J.T.

    1987-09-15

    A control system for controlling the direction of rotation of a rotor of an induction motor includes an array of five triacs with one of the triacs applying a current of fixed phase to the windings of the rotor and four of the triacs being switchable to apply either hot ac current or return ac current to the stator windings so as to reverse the phase of current in the stator relative to that of the rotor and thereby reverse the direction of rotation of the rotor. Switching current phase in the stator is accomplished by operating the gates of pairs of the triacs so as to connect either hot ac current or return ac current to the input winding of the stator. 1 fig.

  10. Directed flux motor

    NASA Technical Reports Server (NTRS)

    Wilson, Andrew (Inventor); Punnoose, Andrew (Inventor); Strausser, Katherine (Inventor); Parikh, Neil (Inventor)

    2011-01-01

    A directed flux motor described utilizes the directed magnetic flux of at least one magnet through ferrous material to drive different planetary gear sets to achieve capabilities in six actuated shafts that are grouped three to a side of the motor. The flux motor also utilizes an interwoven magnet configuration which reduces the overall size of the motor. The motor allows for simple changes to modify the torque to speed ratio of the gearing contained within the motor as well as simple configurations for any number of output shafts up to six. The changes allow for improved manufacturability and reliability within the design.

  11. Flagellar motor based micro hybrid devices.

    PubMed

    Tung, S; Kim, J-W

    2004-01-01

    We are in the process of developing a series of micro hybrid devices based on tethered flagellar motors. Examples of the devices include a microfluidic pump and a micro AC dynamo. The microfluidic pump is realized through the tethering of a harmless strain of Escherichia coli cells to a MEMS based micro channel. Each E. coli cell is about 3 mum long and 1 mum in diameter, with several flagella that are driven at the base by molecular rotary motors. The operational principle of the micro pump is based on the viscous pumping effect where continuous rotation of the tethered cells forms a fluidic conveyor belt that 'drags' fluid from one end of the channel to the other. We used hydrodynamic loading to synchronize cell rotation in order to maximize the fluid pumping capability. The micro dynamo is realized through the integration of tethered flagellar motors with micro ferromagnetic beads and micro copper coils. The micro dynamo generates AC power by using the tethered cells to create a rotating magnetic field around the copper coils. Preliminary result indicates a high power density when compared to other biologically based micro power generators. PMID:17270806

  12. Comparison of AC drives for electric vehicles -- A report on experts` opinion survey

    SciTech Connect

    Chang, L.

    1994-08-01

    It is recognized that wide applications of electric vehicles (EVs) will bring tremendous social, economical and ecological benefits. With the growing interests in electric vehicles, much effort is demanded for the development of efficient, reliable and economical AC drives` for EV propulsion purpose. Both induction motor (IM) drives and permanent magnet brushless DC motor (BDCM) drives have been applied to EVs. Switched reluctance motor (SRM) drives have been proposed as an alternative for EV propulsion. In order to assess the suitability of IM, BDCM and SRM drives for EV applications and to provide a technical support for the development and selection of future EV propulsion systems, the existing EV AC propulsion drives were compared, and a survey of experts` opinions was conducted. Comparison of the three AC drives was made on a relative and a quantitative basis using the survey questionnaires. According to the majority of the experts, induction motor drives are best suited for EV propulsion purpose, due to their low cost, high reliability, high speed, established converter and manufacturing technology, low torque ripple/noise and absence of position sensors. BDCM drives feature compactness, low weight and high efficiency and therefore provide an alternative for EV propulsion. The experts regard insulated gate bipolar transistors (IGBTs) as the most suited power semiconductor devices for AC drive converters at the present stage. 7 refs.

  13. Adaptative Variable Structure Control for an Online Tuning Direct Vector Controlled Induction Motor Drives

    NASA Astrophysics Data System (ADS)

    Lasaad, Sbita; Dalila, Zaltni; Naceurq, Abdelkrim Mohamed

    This study demonstrates that high performance speed control can be obtained by using an adaptative sliding mode control method for a direct vector controlled Squirrel Cage Induction Motor (SCIM). In this study a new method of designing a simple and effective adaptative sliding mode rotational speed control law is developed. The design includes an accurate sliding mode flux observation from the measured stator terminals and rotor speed. The performance of the Direct Field-Orientation Control (DFOC) is ensured by online tuning based on a Model Reference Adaptative System (MRAS) rotor time constant estimator. The control strategy is derived in the sense of Lyapunov stability theory so that the stable tracking performance can be guaranteed under the occurrence of system uncertainties and external disturbances. The proposed scheme is a solution for a robust and high performance induction motor servo drives. Simulation results are provided to validate the effectiveness and robustness of the developed methodology.

  14. Design of a high-efficiency discrete servo-flap actuator for helicopter rotor control

    NASA Astrophysics Data System (ADS)

    Prechtl, Eric F.; Hall, Steven R.

    1997-06-01

    Discrete trailing edge servo-flap actuator designs for use in rotor control applications are considered. A survey was conducted comparing the pros and cons of a number of feasible actuator designs. The major conclusions from this survey indicate that any successful actuator design will utilize a high bandwidth active material, produce large amplification of the active material stroke, and incorporate a simple compressive pre-stress mechanism while remaining efficient in a mass normalized sense. The mass efficiency, defined as the ratio of the specific work performed to the specific energy available, was used as a metric to rate the actuators considered in this survey. Thus, unnecessarily heavy actuators are penalized, which is appropriate when designing components operating under high centrifugal forces. The most feasible discrete actuators are those where the active material reacts against an inert support frame housing. An upper bound on the mass efficiency of this type of actuator is shown to be a function of the ratio of active material to frame specific moduli. A new high efficiency discrete actuator called the x- frame actuator, developed at MIT, and designed in accordance with the lessons learned from the actuator survey, is described. A prototype of this actuator, 150% of model scale, was built and tested on the bench top to confirm the predicted performance. The prototype demonstrates an output energy density of 14.6 ft-lb/slug. It also has a bandwidth of 543 Hz upon driving a nearly impedance matched load. This performance is shown to correspond to a mass efficiency between 18 and 31%.

  15. Fine motor control

    MedlinePlus

    ... figure out the child's developmental age. Children develop fine motor skills over time, by practicing and being taught. To have fine motor control, children need: Awareness and planning Coordination ...

  16. Chronic motor tic disorder

    MedlinePlus

    Chronic vocal tic disorder; Tic - chronic motor tic disorder ... Chronic motor tic disorder is more common than Tourette syndrome . Chronic tics may be forms of Tourette syndrome. Tics usually start ...

  17. MOV motor and gearbox performance under design basis loads

    SciTech Connect

    DeWall, K.G.; Watkins, J.C.; Weidenhamer, G.H.

    1998-06-01

    This paper describes the results of valve testing sponsored by the US Nuclear Regulatory Commission, Office of Nuclear Regulatory Research and conducted at the Idaho National Engineering and Environmental Laboratory. The research objective was to evaluate the capabilities of specific actuator motor and gearbox assemblies under various design basis loading conditions. The testing was performed using the motor-operated valve load simulator, a test fixture that simulates the stem load profiles a valve actuator would experience when closing a valve against flow and pressure loadings. The authors tested five typical motors (four ac motors and one dc motor) with three gearbox assemblies at conditions a motor might experience in a power plant, including such off-normal conditions as operation at high temperature and reduced voltage. The authors also determined the efficiency of the actuator gearbox. The testing produced the following significant results: all five motors operated at or above their rated torque during tests at full voltage and ambient temperature; for all five motors (dc as well as ac), the actual torque loss due to voltage degradation was greater than the torque loss predicted using common methods; startup torques in locked rotor tests compared well with stall torques in dynamometer-type tests; the methods commonly used to predict torque losses due to elevated operating temperatures sometimes bounded the actual losses, but not in all cases; the greatest discrepancy involved the prediction for the dc motor; running efficiencies published by the manufacturer for actuator gearboxes were higher than the actual efficiencies determined from testing, in some instances, the published pullout efficiencies were also higher than the actual values; operation of the gearbox at elevated temperature did not affect the operating efficiency.

  18. AC photovoltaic module magnetic fields

    SciTech Connect

    Jennings, C.; Chang, G.J.; Reyes, A.B.; Whitaker, C.M.

    1997-12-31

    Implementation of alternating current (AC) photovoltaic (PV) modules, particularly for distributed applications such as PV rooftops and facades, may be slowed by public concern about electric and magnetic fields (EMF). This paper documents magnetic field measurements on an AC PV module, complementing EMF research on direct-current PV modules conducted by PG and E in 1993. Although not comprehensive, the PV EMF data indicate that 60 Hz magnetic fields (the EMF type of greatest public concern) from PV modules are comparable to, or significantly less than, those from household appliances. Given the present EMF research knowledge, AC PV module EMF may not merit considerable concern.

  19. Smart motor technology

    NASA Technical Reports Server (NTRS)

    Packard, D.; Schmitt, D.

    1984-01-01

    Current spacecraft design relies upon microprocessor control; however, motors usually require extensive additional electronic circuitry to interface with these microprocessor controls. An improved control technique that allows a smart brushless motor to connect directly to a microprocessor control system is described. An actuator with smart motors receives a spacecraft command directly and responds in a closed loop control mode. In fact, two or more smart motors can be controlled for synchronous operation.

  20. Progress on advanced dc and ac induction drives for electric vehicles

    NASA Technical Reports Server (NTRS)

    Schwartz, H. J.

    1982-01-01

    Progress is reported in the development of complete electric vehicle propulsion systems, and the results of tests on the Road Load Simulator of two such systems representative of advanced dc and ac drive technology are presented. One is the system used in the DOE's ETV-1 integrated test vehicle which consists of a shunt wound dc traction motor under microprocessor control using a transistorized controller. The motor drives the vehicle through a fixed ratio transmission. The second system uses an ac induction motor controlled by transistorized pulse width modulated inverter which drives through a two speed automatically shifted transmission. The inverter and transmission both operate under the control of a microprocessor. The characteristics of these systems are also compared with the propulsion system technology available in vehicles being manufactured at the inception of the DOE program and with an advanced, highly integrated propulsion system upon which technology development was recently initiated.

  1. A Modern Control Theory Based Algorithm for Control of the NASA/JPL 70-Meter Antenna Axis Servos

    NASA Astrophysics Data System (ADS)

    Hill, R. E.

    1987-09-01

    A digital computer-based state variable controller has been designed and applied to the 70-m antenna azis servos. The general equations and structure of the algorithm and provisions for alternate position error feedback modes to accomodate intertarget slew, encoder references tracking, and precision tracking modes are described. Development of the discrete time domain control model and computation of estimator and control gain parameters based on closed loop pole placement criteria are discussed. The new algorithm has been successfully implemented and tested in the 70-m antenna at Deep Space Station (DSS) 63 in Spain.

  2. Study on Dynamical Simulation of Railway Vehicle Bogie Parameters Test-bench Electro-hydraulic Servo System

    NASA Astrophysics Data System (ADS)

    Lan, Zhikun; Su, Jian; Xu, Guan; Cao, Xiaoning

    Dynamical mathematical model was established for accurately positioning, fast response and real-time tracing of electro-hydraulic servo control system in railway vehicle bog ie parameters test system with elastic load. The model could precisely control the output of position and force of the hydraulic cylinders. Induction method was proposed in the paper. Dynamical simulation verified the mathematical model by SIMULINK software. Meanwhile the key factors affecting the dynamical characteristics of the system were discussed in detail. Through the simulation results, high precision is obtained in application and the need of real-time control on the railway vehicle bogie parameters test-bench is realized.

  3. A modern control theory based algorithm for control of the NASA/JPL 70-meter antenna axis servos

    NASA Technical Reports Server (NTRS)

    Hill, R. E.

    1987-01-01

    A digital computer-based state variable controller was designed and applied to the 70-m antenna axis servos. The general equations and structure of the algorithm and provisions for alternate position error feedback modes to accommodate intertarget slew, encoder referenced tracking, and precision tracking modes are descibed. Development of the discrete time domain control model and computation of estimator and control gain parameters based on closed loop pole placement criteria are discussed. The new algorithm was successfully implemented and tested in the 70-m antenna at Deep Space Network station 63 in Spain.

  4. Solid propellant motor

    NASA Technical Reports Server (NTRS)

    Shafer, J. I.; Marsh, H. E., Jr. (Inventor)

    1978-01-01

    A case bonded end burning solid propellant rocket motor is described. A propellant with sufficiently low modulus to avoid chamber buckling on cooling from cure and sufficiently high elongation to sustain the stresses induced without cracking is used. The propellant is zone cured within the motor case at high pressures equal to or approaching the pressure at which the motor will operate during combustion. A solid propellant motor with a burning time long enough that its spacecraft would be limited to a maximum acceleration of less than 1 g is provided by one version of the case bonded end burning solid propellant motor of the invention.

  5. Motor/generator

    DOEpatents

    Hickam, Christopher Dale

    2008-05-13

    A motor/generator is provided for connecting between a transmission input shaft and an output shaft of a prime mover. The motor/generator may include a motor/generator housing, a stator mounted to the motor/generator housing, a rotor mounted at least partially within the motor/generator housing and rotatable about a rotor rotation axis, and a transmission-shaft coupler drivingly coupled to the rotor. The transmission-shaft coupler may include a clamp, which may include a base attached to the rotor and a plurality of adjustable jaws.

  6. Thin-disc piezoceramic ultrasonic motor. Part II: system construction and control.

    PubMed

    Yen, Chi Yung; Wen, Fuh Liang; Ouyang, Minsun

    2003-08-01

    Design and performance evaluation of an ultrasonic motor was discussed in [Wen et al., Thin-disc piezoelectric ultrasonic motor. Part I: design and performance evaluation, Ultrasonics]. Higher precision position control of piezoceramic ultrasonic motor depends on mechanical design and servo control of a very precise and adequate metrology. This paper proposes the design of a driving circuit and controller to deal with non-linearities behavior in the model of piezoceramic-driving ultrasonic motor. The performance of the driver and the effectiveness of the proposed controller are demonstrated by command inputs of sinusoidal and step signals. For comparison purpose, the ultrasonic motor is controlled using two methods: i.e., proportional-integral-derivative (PID) and sliding-mode control (SMC). It was proven that SMC would compensate automatically for unmodeled behaviors such as piezoceramic non-linearities and mechanical stick-slip phenomena. Furthermore, SMC scheme has been successfully applied to position tracking to demonstrate the excellent robust performance in noise rejection. PMID:12853081

  7. Stabilizer of shaft rotation angle for D.C. commutator motor

    NASA Astrophysics Data System (ADS)

    Nizovoy, S. N.; Kuliczhanov, F. G.; Yelyutin, N. O.

    1986-02-01

    A stabilizer of shaft rotation angle for d.c. commutator motors is described which suppresses speed fluctuation caused by a change in the armature current as successive commutator bars reach the leading edge of a brush. This is achieved by inserting a low series resistance into the armature circuit and feeding the voltage across it to a servo oscillograph so that the frequency of the driven sweep becomes a multiple of the shaft speed. Return-stroke sweep pulses are extracted from the sawtooth voltage wave by a shaping circuit which consists of one capacitor, one resistor, two diodes, and one trigger. After a specified number of pulses has accumulated, another trigger actuates a switch which disconnects the motor from the voltage supply. A single starting pulse at the output of another shaping circuit records a specified number in the same pulse counter, through arrays of switches, and sets the same trigger for reconnecting the motor to the voltage supply. This stabilizer was tested on a positioning table driven by an MN-250 motor with 6-bar commutator, using an S1-19B oscillograph. The motor was started in steps for rotation in 3 minute steps, and the table position was measured after each 20 steps by means of a theodolite within + or - 4 sec accuracy. The average instability of the rotation angle between measurements did not exceed + or 30 sec.

  8. Research on PID controller with input shaping algorithm for linear motor

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Dong, Yue; Fan, Wenchao; Fu, Zhenxian

    2015-02-01

    The reticle stage of lithography is a high precision servo motion platform, which requires using macro movement of linear motor and micro movement of voice coil motor to realize an nm-level positioning precision and tracking. In order to increase the control effect and response speed of macro movement linear motor of reticle stage of lithography, the paper presents an efficient control for linear motor. The method use input shaping technique with Proportional Integral Derivative (PID) controller to realize the high position precision in small stetting time. In the paper we firstly build the linear motor mathematical modeling which is end to velocity loop or position loop. so that we mainly focus on the tracking of speed signal. Then a PID controller is introduced in the system, which is high frequency used in industrial control. Finally, as the need of high positioning precision and small stetting time, we apply input shaping algorithm to solve the problem. The simulation of the system is performed by using MATLAB/Simulation. The evaluation of the method is the performance of input tracking capability.

  9. Motorized support jack

    DOEpatents

    Haney, Steven J.; Herron, Donald Joe

    2001-01-01

    A compact, vacuum compatible motorized jack for supporting heavy loads and adjusting their positions is provided. The motorized jack includes: (a) a housing having a base; (b) a first roller device that provides a first slidable surface and that is secured to the base; (c) a second roller device that provides a second slidable surface and that has an upper surface; (d) a wedge that is slidably positioned between the first roller device and the second roller device so that the wedge is in contact with the first slidable surface and the second slidable surface; (e) a motor; and (d) a drive mechanism that connects the motor and the wedge to cause the motor to controllably move the wedge forwards or backwards. Individual motorized jacks can support and lift of an object at an angle. Two or more motorized jacks can provide tip, tilt and vertical position adjustment capabilities.

  10. Motorized support jack

    DOEpatents

    Haney, Steven J.; Herron, Donald Joe

    2003-05-13

    A compact, vacuum compatible motorized jack for supporting heavy loads and adjusting their positions is provided. The motorized jack includes: (a) a housing having a base; (b) a first roller device that provides a first slidable surface and that is secured to the base; (c) a second roller device that provides a second slidable surface and that has an upper surface; (d) a wedge that is slidably positioned between the first roller device and the second roller device so that the wedge is in contact with the first slidable surface and the second slidable surface; (e) a motor; and (d) a drive mechanism that connects the motor and the wedge to cause the motor to controllably move the wedge forwards or backwards. Individual motorized jacks can support and lift of an object at an angle. Two or more motorized jacks can provide tip, tilt and vertical position adjustment capabilities.

  11. Asynchronous Motor Nonlinear Control with Inverter Output LC Filter

    NASA Astrophysics Data System (ADS)

    Guzinski, J.; Abu-Rub, H.

    2009-03-01

    In many adjustable electric drives the LC filter is used to smooth the voltages and currents supplying AC motors. The LC filter makes it difficult to implement precise control of these motors especially in the case of speed sensorless solution. Because measuring motor currents and capacitor voltages is not practical, a preferable solution is to measure only filter input current. A good approach is to use observers to restore unmeasured state variables. Additionally, it is necessary to modify the used control in case of the drive with LC filter. In this paper the proposed system with nonlinear control method of the asynchronous motor, and the speed and flux observer structure were been adapted regarding the LC filter. In the presented drive only sensors previously used in the system without LC filter were used. 1.5 kW drive was verified in by simulation and experiments.

  12. Integration of a piezoelectric transformer and an ultrasonic motor.

    PubMed

    Manuspiya, Suwan; Laoratanakul, Pitak; Uchino, Kenji

    2003-03-01

    Ultrasonic motors are usually operated at an AC voltage higher than a regular battery. This implies the need of a voltage step-up transformer. In this paper, we report the integration of a piezoelectric transformer (PT) with an ultrasonic motor and a simple drive circuit. The stator of the ultrasonic motor and the PT were operated in the same radial vibration mode. Their dimensions were very close to each other yielding nearly matching resonance frequencies. Consequently, they could be combined together without inductor. The drive circuit was designed by using a 555 timer as an astable multivibrator, and high-speed dual MOSFET drivers as a class D half-bridge switching amplifier. This integrated PT-ultrasonic motor performed reasonably without the use of electromagnetic transformer or inductor. PMID:12565071

  13. Stepper motor drive for on load tapchanger in electric locomotive

    SciTech Connect

    Aruna Kumar, G.V.D.; Kumar, S.; Mishra, P.; Wadhonkar, N.K.

    1995-12-31

    Indian Railways have a fleet of 2,200 electrical locomotives running on 25 KV ac traction. An on-load tap changer is used to select voltage for speed control of dc traction motor. A four stroke reciprocating type air motor is used presently to drive the tap changer (GR). Complex gear and camshaft mechanism is used to move tap changer and to generate various logic signals for safe loco operation. The annual failure rate for tap changer and its drive is of the order of 20%. A microprocessor controlled stepper motor drive has been designed and constructed to drive the on-load tap changer. A current controlled chopper is used to drive the motor and control logic has been generated through an optimum hardware and software combination. The assembly has been tested on a prototype tap changer in the laboratory.

  14. Electric drive motors for industrial robots

    NASA Astrophysics Data System (ADS)

    Fichtner, K.

    1985-04-01

    In robotized industrial plants it is possible to use electric motors in the technological process and also for control, assembly, transport, testing, and measurements. Particularly suitable for these applications are permanent-magnet d.c. motors. A new special series was developed for industrial robots with hinge joints in kinematic pairs. The complete drive includes thyristors or transistor controls with regulators and, if necessary, a line transformer as well as a servomotor with tachometer and odometer for speed, current, and position control. The drive is coupled to a robot tong through mechanical torque and force converters. In addition to a 0 to 4000 rpm speed regulation, without wobble at low speeds, and a high torque-to-weight ratio for repetitive short-time heavy duty, these low-inertia motors develop high starting and accelerating torques over the entire speed range. They operate from a 1 to O 220 V a.c. line through a rectifier. The motors are totally enclosed, or of open construction for better ventilation. Their windings have class F insulation for operation at ambient temperatures up to 40 C.

  15. A compound control strategy combining velocity compensation with ADRC of electro-hydraulic position servo control system.

    PubMed

    Gao, Bingwei; Shao, Junpeng; Yang, Xiaodong

    2014-11-01

    In order to enhance the anti-jamming ability of electro-hydraulic position servo control system at the same time improve the control precision of the system, a compound control strategy that combines velocity compensation with Active Disturbance Rejection Controller (ADRC) is proposed, and the working principle of the compound control strategy is given. ADRC controller is designed, and the extended state observer is used for observing internal parameters uncertainties and external disturbances, so that the disturbances of the system are suppressed effectively. Velocity compensation controller is designed and the compensation model is derived to further improve the positioning accuracy of the system and to achieve the velocity compensation without disturbance. The compound control strategy is verified by the simulation and experiment respectively, and the simulation and experimental results show that the electro-hydraulic position servo control system with ADRC controller can effectively inhibit the external disturbances, the precise positioning control is realized after introducing the velocity compensation controller, and verify that the compound control strategy is effective. PMID:25085480

  16. Large-scale fabrication of micro-lens array by novel end-fly-cutting-servo diamond machining.

    PubMed

    Zhu, Zhiwei; To, Suet; Zhang, Shaojian

    2015-08-10

    Fast/slow tool servo (FTS/STS) diamond turning is a very promising technique for the generation of micro-lens array (MLA). However, it is still a challenge to process MLA in large scale due to certain inherent limitations of this technique. In the present study, a novel ultra-precision diamond cutting method, as the end-fly-cutting-servo (EFCS) system, is adopted and investigated for large-scale generation of MLA. After a detailed discussion of the characteristic advantages for processing MLA, the optimal toolpath generation strategy for the EFCS is developed with consideration of the geometry and installation pose of the diamond tool. A typical aspheric MLA over a large area is experimentally fabricated, and the resulting form accuracy, surface micro-topography and machining efficiency are critically investigated. The result indicates that the MLA with homogeneous quality over the whole area is obtained. Besides, high machining efficiency, extremely small volume of control points for the toolpath, and optimal usage of system dynamics of the machine tool during the whole cutting can be simultaneously achieved. PMID:26367912

  17. Fuel-free locomotion of Janus motors: magnetically induced thermophoresis.

    PubMed

    Baraban, Larysa; Streubel, Robert; Makarov, Denys; Han, Luyang; Karnaushenko, Dmitriy; Schmidt, Oliver G; Cuniberti, Gianaurelio

    2013-02-26

    We present fuel-free locomotion of magnetic spherical Janus motors driven by magnetically induced thermophoresis--a self-diffusive propulsion of an object in any liquid media due to a local temperature gradient. Within this approach an ac magnetic field is applied to induce thermophoretic motion of the objects via heating a magnetic cap of the particles, while an additional dc magnetic field is used to orient Janus motors and guide their motion on a long time scale. Full control over the motion is achieved due to specific properties of ultrathin 100-nm-thick Permalloy (Py, Fe₁₉Ni₈₁ alloys) magnetic films resulting in a topologically stable magnetic vortex state in the cap structure of Janus motors. Realized here magnetically induced thermophoretic locomotion does not require catalytic chemical reactions that imply toxic reagents. In this respect, we addressed and successfully solved one of the main shortcomings in the field of artificial motors, namely being fully controlled and remain biocompatible. Therefore, our approach is attractive for biotechnological in vitro assays and even in vivo operations, since the functioning of Janus motors offers low toxicity; it is not dependent on the presence of the fuel molecules in solution. Furthermore, the suggested magnetic ac excitation is superior compared to the previously proposed optically induced heating using lasers as it does not require transparent packaging. PMID:23268780

  18. Constant slip control of induction motor at light load

    SciTech Connect

    Feng Xiaogang; Chen Boshi

    1996-12-31

    The most widely used AC motor drives adopt Rated Flux Control (RFC) method. However, at light load condition, RFC causes excessive iron loss, thus the conversion efficiency of the drive system impaired. This paper introduces a new control approach--Constant Slip Control (CSC), which minimize the stator current at light load, so that the iron loss and reactive power consumption of the motor are decreased. Simulation results compare the power consumption of CSC with that of RFC in order to validate the theoretical development. In the last part, realization of CSC is discussed.

  19. Piezoelectric Motors and Transformers

    NASA Astrophysics Data System (ADS)

    Uchino, K.

    Piezoelectric ceramics forms a new field between electronic and structural ceramics [1-4]. Application fields are classified into three categories: positioners, motors, and vibration suppressors. From the market research result for 80 Japanese component industries in 1992, tiny motors in the range of 5-8 mm are required in large numbers for office and portable equipment; the conventional electromagnetic (EM) motors are rather difficult to produce in this size with sufficient energy efficiency, while Silicon MEMS actuators are too small to be used in practice. Piezoelectric ultrasonic motors whose efficiency is insensitive to size are superior in the millimeter motor area. The manufacturing precision of optical instruments such as lasers and cameras, and the positioning accuracy for fabricating semiconductor chips are of the order of 0.1μm which is much smaller than the backlash of the EM motors. Vibration suppression in space structures and military vehicles also require compact but mighty piezoelectric actuators.

  20. Multifocal motor neuropathy.

    PubMed

    Muley, Suraj Ashok; Parry, Gareth J

    2012-09-01

    Multifocal motor neuropathy (MMN) was first described in 1988 as a purely motor neuropathy affecting multiple motor nerves. The diagnosis was based entirely on demonstrating electrophysiological evidence of a conduction block (CB) that selectively affected motor axons, with sparing of sensory axons even through the site of motor CB. Subsequently, a similar disorder was reported but with absence of demonstrable CB on routine nerve conduction studies and there is still some debate as to whether MMN without CB is related to MMN. MMN is thought to be an inflammatory neuropathy related to an immune attack on motor nerves. The conventional hypothesis is that the primary pathology is segmental demyelination, but recent research raises the possibility of a primary axonopathy. Anti-GM1 antibodies can be found in some patients but it is unclear whether these antibodies are pathogenic. Intravenous immunoglobulin is the mainstay of treatment but other immunosuppressive treatments can also be effective. PMID:22743043

  1. Numerical analysis and finite element modelling of an HTS synchronous motor

    NASA Astrophysics Data System (ADS)

    Ainslie, M. D.; Jiang, Y.; Xian, W.; Hong, Z.; Yuan, W.; Pei, R.; Flack, T. J.; Coombs, T. A.

    2010-11-01

    This paper investigates the electromagnetic properties of high-temperature superconductors with a particular focus on the AC loss in coils made from YBCO superconductors. The numerical analysis and finite element modelling of the YBCO superconductors used in Cambridge’s superconducting permanent magnet synchronous motor currently in development is described. The stack of tapes in the superconducting coils is modelled using the direct H formulation, a B-dependent critical current density and a bulk approximation. Magnetic boundary conditions for this model are derived from a 2D finite element method (FEM) motor model. The combination of these models allows the total AC loss (combined transport and magnetisation losses) in the HTS coils used in an all-superconducting machine design to be estimated. The raw AC loss figures are compared to the output power of the motor for two test cases, and it is found that the AC loss contributes significantly to the total loss and therefore efficiency. An experimental rig is also described, which has been built in order to test the electromagnetic properties and performance of the motor. It is explained how this rig will be used to investigate the magnetisation of the rotor and carry out AC loss measurements on the stator coils.

  2. Hybrid vehicle motor alignment

    DOEpatents

    Levin, Michael Benjamin

    2001-07-03

    A rotor of an electric motor for a motor vehicle is aligned to an axis of rotation for a crankshaft of an internal combustion engine having an internal combustion engine and an electric motor. A locator is provided on the crankshaft, a piloting tool is located radially by the first locator to the crankshaft. A stator of the electric motor is aligned to a second locator provided on the piloting tool. The stator is secured to the engine block. The rotor is aligned to the crankshaft and secured thereto.

  3. Cryogenic Electric Motor Tested

    NASA Technical Reports Server (NTRS)

    Brown, Gerald V.

    2004-01-01

    Technology for pollution-free "electric flight" is being evaluated in a number of NASA Glenn Research Center programs. One approach is to drive propulsive fans or propellers with electric motors powered by fuel cells running on hydrogen. For large transport aircraft, conventional electric motors are far too heavy to be feasible. However, since hydrogen fuel would almost surely be carried as liquid, a propulsive electric motor could be cooled to near liquid hydrogen temperature (-423 F) by using the fuel for cooling before it goes to the fuel cells. Motor windings could be either superconducting or high purity normal copper or aluminum. The electrical resistance of pure metals can drop to 1/100th or less of their room-temperature resistance at liquid hydrogen temperature. In either case, super or normal, much higher current density is possible in motor windings. This leads to more compact motors that are projected to produce 20 hp/lb or more in large sizes, in comparison to on the order of 2 hp/lb for large conventional motors. High power density is the major goal. To support cryogenic motor development, we have designed and built in-house a small motor (7-in. outside diameter) for operation in liquid nitrogen.

  4. Development of a radial-torsional vibration hybrid type ultrasonic motor with a hollow and short cylindrical structure.

    PubMed

    Wang, Jian; Guo, Jifeng

    2009-05-01

    A longitudinal-torsional hybrid-type ultrasonic motor has larger torque and lower revolution speed compared with other kinds of ultrasonic motors. It drives devices directly and precisely, so it is adaptable to many fields, especially aeronautics and astronautics, as a servo actuator. Due to the different sound propagation speeds of longitudinal and torsional vibrations in the stator, it is difficult to match resonant frequencies of longitudinal and torsional vibrations. In this paper, a new radial-torsional vibration hybrid-type ultrasonic motor is put forward, which utilizes longitudinal vibration derived from radial vibration by the Poisson effect. The short, hollow cylindrical structure easily makes resonant frequencies of first-order radial and torsional vibrations into degeneracy. First, the new structure of the motor is presented. Second, the principle of matching the resonant frequencies is developed, and the motor geometry is optimized by ANSYS software. Finally, a 60-mm diameter prototype is fabricated, which performs well. The no-load velocity and maximum torque are 25 r/min and 5 N x m, respectively. This kind of motor is small, light, and noiseless. PMID:19473923

  5. ac powertrain for an electric vehicle. Phase 2 and Phase 3 final report

    SciTech Connect

    Slicker, J.M.

    1984-11-01

    This report describes work relating to Phases 2 and 3 development and testing of an ac powertrain for a 25 hp four-passenger electric vehicle. The system, which consists of a two-speed automatic mechanical transaxle, 18.6 kW ac induction traction motor, 33.6 kW inverter and overall logic controller, was installed and evaluated in a converted Mercury Lynx rolling test bed vehicle. An on-board charger and an auxiliary dc-to-dc converter were integrated into the inverter/controller package.

  6. Distribution of AC loss in a HTS magnet for SMES with different operating conditions

    NASA Astrophysics Data System (ADS)

    Xu, Y.; Tang, Y.; Ren, L.; Jiao, F.; Song, M.; Cao, K.; Wang, D.; Wang, L.; Dong, H.

    2013-11-01

    The AC loss induced in superconducting tape may affect the performance of a superconducting device applied to power system, such as transformer, cable, motor and even Superconducting Magnetic Energy Storage (SMES). The operating condition of SMES is changeable due to the need of compensation to the active or reactive power according to the demand of a power grid. In this paper, it is investigated that the distribution of AC loss for a storage magnet on different operating conditions, which is based on finite element method (FEM) and measured properties of BSCCO/Ag tapes. This analytical method can be used to optimize the SMES magnet.

  7. Vibration in a Triac-Controlled-Permanent-Split-Capacitor Fan Motor

    NASA Astrophysics Data System (ADS)

    Tozune, Akira

    In a triac controlled-split-capacitor motor, vibration and acoustic noise are produced by the interaction of the time-harmonic field. This paper describes the vibration of a fan motor which may be produced when speed is controlled using a conventional triac AC controller Pulasting torque is analysed by the electromagnetic method and pulsating troque equations are derived. The vibration spectrum of a motor with triac excitation are mesured in three vibrational directions under various operating conditions. It is shown that the connection of a triac in series with the main winding is more effective for the reduction of vibration and power input than that in series with motor supply. It is also shown that the value of capacitor chosen for optimum motor performance with a main-frequency sinusoldal supply is not always the same as that for minimizing motor vibration.

  8. Heritability of motor control and motor learning

    PubMed Central

    Missitzi, Julia; Gentner, Reinhard; Misitzi, Angelica; Geladas, Nickos; Politis, Panagiotis; Klissouras, Vassilis; Classen, Joseph

    2013-01-01

    Abstract The aim of this study was to elucidate the relative contribution of genes and environment on individual differences in motor control and acquisition of a force control task, in view of recent association studies showing that several candidate polymorphisms may have an effect on them. Forty‐four healthy female twins performed brisk isometric abductions with their right thumb. Force was recorded by a transducer and fed back to the subject on a computer screen. The task was to place the tracing of the peak force in a force window defined between 30% and 40% of the subject's maximum force, as determined beforehand. The initial level of proficiency was defined as the number of attempts reaching the force window criterion within the first 100 trials. The difference between the number of successful trials within the last and the first 100 trials was taken as a measure of motor learning. For motor control, defined by the initial level of proficiency, the intrapair differences in monozygotic (MZ) and dizygotic (DZ) twins were 6.8 ± 7.8 and 13.8 ± 8.4, and the intrapair correlations 0.77 and 0.39, respectively. Heritability was estimated at 0.68. Likewise for motor learning intrapair differences in the increment of the number of successful trials in MZ and DZ twins were 5.4 ± 5.2 and 12.8 ± 7, and the intrapair correlations 0.58 and 0.19. Heritability reached 0.70. The present findings suggest that heredity accounts for a major part of existing differences in motor control and motor learning, but uncertainty remains which gene polymorphisms may be responsible. PMID:24744865

  9. Adjustable Speed Drive Part-Load Efficiency - Motor Tip Sheet #11

    SciTech Connect

    2008-07-01

    An adjustable speed drive (ASD) is a device that controls the rotational speed of motor-driven equipment. Variable frequency drives (VFDs), the most common type of ASDs, efficiently meet varying process requirements by adjusting the frequency and voltage of the power supplied to an AC motor to enable it to operate over a wide speed range. External sensors monitor flow, liquid levels, or pressure and then transmit a signal to a controller that adjusts the frequency and speed to match process requirements.

  10. A study on the integration of contactless energy transfer in the end teeth of a PM synchronous linear motor

    NASA Astrophysics Data System (ADS)

    Krop, D. C. J.; Lomonova, E. A.; Jansen, J. W.; Paulides, J. J. H.

    2009-04-01

    Linear motors find their utilization in an increasing number of industrial applications. Permanent magnet linear synchronous motors (PMLSMs) are favorable in many applications due to their servo characteristics, robustness, and high force density. The major disadvantage of moving coil type PMLSMs is the cable slab that energizes the coils from the fixed world to the moving parts of the machine. These cable slabs introduce extra wear and dynamical distortions. Moreover, in precision application the cable slab is supported by additional linear drives. These disadvantages can be eliminated if the coils could be powered wirelessly. In this paper two topologies are proposed that are capable of transferring 1 kW of power at most. The transformer part of the CET is characterized by means of two dimensional finite element analysis, and the influence of using additional capacitors to boost the output power is examined. Furthermore, an analysis of the core losses is conducted. Conclusions are drawn from the results.

  11. Closed-loop motor control using high-speed fiber optics

    NASA Technical Reports Server (NTRS)

    Dawson, Reginald (Inventor); Rodriquiz, Dagobert (Inventor)

    1991-01-01

    A closed-loop control system for controlling the operation of one or more servo motors or other controllable devices is described. The system employs a fiber optics link immune to electromagnetic interference, for transmission of control signals from a controller or controllers at a remote station to the power electronics located in proximity to the motors or other devices at the local station. At the remote station the electrical control signals are time-multiplexed, converted to a formatted serial bit stream, and converted to light signals for transmission over a single fiber of the fiber optics link. At the local station, the received optical signals are reconstructed as electrical control signals for the controlled motors or other devices. At the local station, an encoder sensor linked to the driven device generates encoded feedback signals which provide information as to a condition of the controlled device. The encoded signals are placed in a formatted serial bit stream, multiplexed, and transmitted as optical signals over a second fiber of the fiber optic link which closes the control loop of the closed-loop motor controller. The encoded optical signals received at the remote station are demultiplexed, reconstructed and coupled to the controller(s) as electrical feedback signals.

  12. Motor Vehicle Safety

    MedlinePlus

    ... from motor vehicle crashes. Trying to prevent these crashes is one part of motor vehicle safety. Here are some things you can do to be safer on the road: Make sure your vehicle is safe and in working order Use car seats for children Wear your seat belt Don' ...

  13. Stepping motor controller

    DOEpatents

    Bourret, S.C.; Swansen, J.E.

    1982-07-02

    A stepping motor is microprocessor controlled by digital circuitry which monitors the output of a shaft encoder adjustably secured to the stepping motor and generates a subsequent stepping pulse only after the preceding step has occurred and a fixed delay has expired. The fixed delay is variable on a real-time basis to provide for smooth and controlled deceleration.

  14. Stepping motor controller

    DOEpatents

    Bourret, Steven C.; Swansen, James E.

    1984-01-01

    A stepping motor is microprocessingly controlled by digital circuitry which monitors the output of a shaft encoder adjustably secured to the stepping motor and generates a subsequent stepping pulse only after the preceding step has occurred and a fixed delay has expired. The fixed delay is variable on a real-time basis to provide for smooth and controlled deceleration.

  15. Hybrid Rocket Motor Test

    NASA Technical Reports Server (NTRS)

    1994-01-01

    A 10,000-pound thrust hybrid rocket motor is tested at Stennis Space Center's E-1 test facility. A hybrid rocket motor is a cross between a solid rocket and a liquid-fueled engine. It uses environmentally safe solid fuel and liquid oxygen.

  16. Input Power Quality Improvement in Switched Reluctance Motor Drive using Minnesota Rectifier

    NASA Astrophysics Data System (ADS)

    Singh, B.; Rajesh, M.

    2013-09-01

    This paper deals with an input power quality improvement in a midpoint converter based switched reluctance motor (SRM) drive at ac mains using Minnesota rectifier. Normally a midpoint converter is used as a power converter for SRM drive. Conventionally three phase ac mains fed bridge rectifier is used as a dc source to feed this power converter which produces high content of harmonics at ac mains with a very low power factor. The proposed Minnesota rectifier with a midpoint converter fed SRM drive improves the power factor at ac mains with low current harmonics. This method provides constant dc link voltage and balanced capacitor voltages of the midpoint converter. The Minnesota rectifier fed SRM drive is modelled and its performance is simulated in Matlab/Simulink environment. The performance of Minnesota rectifier is compared with a conventional bridge topology for SRM drive to demonstrate improved power quality at ac mains.

  17. The ac53, ac78, ac101, and ac103 Genes Are Newly Discovered Core Genes in the Family Baculoviridae

    PubMed Central

    Garavaglia, Matías Javier; Miele, Solange Ana Belén; Iserte, Javier Alonso; Belaich, Mariano Nicolás

    2012-01-01

    The family Baculoviridae is a large group of insect viruses containing circular double-stranded DNA genomes of 80 to 180 kbp, which have broad biotechnological applications. A key feature to understand and manipulate them is the recognition of orthology. However, the differences in gene contents and evolutionary distances among the known members of this family make it difficult to assign sequence orthology. In this study, the genome sequences of 58 baculoviruses were analyzed, with the aim to detect previously undescribed core genes because of their remote homology. A routine based on Multi PSI-Blast/tBlastN and Multi HaMStR allowed us to detect 31 of 33 accepted core genes and 4 orthologous sequences in the Baculoviridae which were not described previously. Our results show that the ac53, ac78, ac101 (p40), and ac103 (p48) genes have orthologs in all genomes and should be considered core genes. Accordingly, there are 37 orthologous genes in the family Baculoviridae. PMID:22933288

  18. Simple Equipment for Imaging AC.

    ERIC Educational Resources Information Center

    Kamata, Masahiro; Anayama, Takayuki

    2003-01-01

    Presents an effective way to demonstrate the difference between direct current and alternating current using red and green LEDs. Describes how to make a tool that shows how an AC voltage changes with time using the afterimage effect of the LEDs. (Author/NB)

  19. Semiconductor ac static power switch

    NASA Technical Reports Server (NTRS)

    Vrancik, J.

    1968-01-01

    Semiconductor ac static power switch has long life and high reliability, contains no moving parts, and operates satisfactorily in severe environments, including high vibration and shock conditions. Due to their resistance to shock and vibration, static switches are used where accidental switching caused by mechanical vibration or shock cannot be tolerated.

  20. Energy saving in ac generators

    NASA Technical Reports Server (NTRS)

    Nola, F. J.

    1980-01-01

    Circuit cuts no-load losses, without sacrificing full-load power. Phase-contro circuit includes gate-controlled semiconductor switch that cuts off applied voltage for most of ac cycle if generator idling. Switch "on" time increases when generator is in operation.

  1. Influence analysis of structural parameters and operating parameters on electromagnetic properties of HTS linear induction motor

    NASA Astrophysics Data System (ADS)

    Fang, J.; Sheng, L.; Li, D.; Zhao, J.; Li, Sh.; Qin, W.; Fan, Y.; Zheng, Q. L.; Zhang, W.

    A novel High Temperature Superconductor Linear Induction Motor (HTS LIM) is researched in this paper. Since the critical current and the electromagnetic force of the motor are determined mainly by the primary slot leakage flux, the main magnetic flux and eddy current respectively, in order to research the influence of structural parameters and operating parameters on electromagnetic properties of HTS LIM, the motor was analyzed by 2D transient Finite Element Method (FEM). The properties of the motor, such as the maximum slot leakage flux density, motor thrust, motor vertical force and critical current are analyzed with different structural parameters and operating parameters. In addition, an experimental investigation was carried out on prototype HTS motor. Electrical parameters were deduced from these tests and also compared with the analysis results from FEM. AC losses of one HTS coil in the motor were measured and AC losses of all HTS coils in HTS LIM were estimated. The results in this paper could provide reference for the design and research on the HTS LIM.

  2. Organizing motor imageries.

    PubMed

    Hanakawa, Takashi

    2016-03-01

    Over the last few decades, motor imagery has attracted the attention of researchers as a prototypical example of 'embodied cognition' and also as a basis for neuro-rehabilitation and brain-machine interfaces. The current definition of motor imagery is widely accepted, but it is important to note that various abilities rather than a single cognitive entity are dealt with under a single term. Here, motor imagery has been characterized based on four factors: (1) motor control, (2) explicitness, (3) sensory modalities, and (4) agency. Sorting out these factors characterizing motor imagery may explain some discrepancies and variability in the findings from previous studies and will help to optimize a study design in accordance with the purpose of each study in the future. PMID:26602980

  3. Induction motor control

    NASA Technical Reports Server (NTRS)

    Hansen, Irving G.

    1990-01-01

    Electromechanical actuators developed to date have commonly utilized permanent magnet (PM) synchronous motors. More recently switched reluctance (SR) motors have been advocated due to their robust characteristics. Implications of work which utilizes induction motors and advanced control techniques are discussed. When induction motors are operated from an energy source capable of controlling voltages and frequencies independently, drive characteristics are obtained which are superior to either PM or SR motors. By synthesizing the machine frequency from a high frequency carrier (nominally 20 kHz), high efficiencies, low distortion, and rapid torque response are available. At this time multiple horsepower machine drives were demonstrated, and work is on-going to develop a 20 hp average, 40 hp peak class of aerospace actuators. This effort is based upon high frequency power distribution and management techniques developed by NASA for Space Station Freedom.

  4. Induction motor control

    NASA Technical Reports Server (NTRS)

    Hansen, Irving G.

    1990-01-01

    Electromechanical actuators developed to date have commonly ultilized permanent magnet (PM) synchronous motors. More recently switched reluctance (SR) motors have been advocated due to their robust characteristics. Implications of work which utilized induction motors and advanced control techniques are discussed. When induction motors are operated from an energy source capable of controlling voltages and frequencies independently, drive characteristics are obtained which are superior to either PM or SR motors. By synthesizing the machine frequency from a high-frequency carrier (nominally 20 kHz), high efficiencies, low distortion, and rapid torque response are available. At this time multiple horsepower machine drives were demonstrated, and work is on-going to develop a 20 hp average, 40 hp peak class of aerospace actuators. This effort is based upon high-frequency power distribution and management techniques developed by NASA for Space Station Freedom.

  5. Induction motor control

    NASA Astrophysics Data System (ADS)

    Hansen, Irving G.

    Electromechanical actuators developed to date have commonly ultilized permanent magnet (PM) synchronous motors. More recently switched reluctance (SR) motors have been advocated due to their robust characteristics. Implications of work which utilized induction motors and advanced control techniques are discussed. When induction motors are operated from an energy source capable of controlling voltages and frequencies independently, drive characteristics are obtained which are superior to either PM or SR motors. By synthesizing the machine frequency from a high-frequency carrier (nominally 20 kHz), high efficiencies, low distortion, and rapid torque response are available. At this time multiple horsepower machine drives were demonstrated, and work is on-going to develop a 20 hp average, 40 hp peak class of aerospace actuators. This effort is based upon high-frequency power distribution and management techniques developed by NASA for Space Station Freedom.

  6. Robust H(∞) positional control of 2-DOF robotic arm driven by electro-hydraulic servo system.

    PubMed

    Guo, Qing; Yu, Tian; Jiang, Dan

    2015-11-01

    In this paper an H∞ positional feedback controller is developed to improve the robust performance under structural and parametric uncertainty disturbance in electro-hydraulic servo system (EHSS). The robust control model is described as the linear state-space equation by upper linear fractional transformation. According to the solution of H∞ sub-optimal control problem, the robust controller is designed and simplified to lower order linear model which is easily realized in EHSS. The simulation and experimental results can validate the robustness of this proposed method. The comparison result with PI control shows that the robust controller is suitable for this EHSS under the critical condition where the desired system bandwidth is higher and the external load of the hydraulic actuator is closed to its limited capability. PMID:26478475

  7. Development of an interface for an ultrareliable fault-tolerant control system and an electronic servo-control unit

    NASA Technical Reports Server (NTRS)

    Shaver, Charles; Williamson, Michael

    1986-01-01

    The NASA Ames Research Center sponsors a research program for the investigation of Intelligent Flight Control Actuation systems. The use of artificial intelligence techniques in conjunction with algorithmic techniques for autonomous, decentralized fault management of flight-control actuation systems is explored under this program. The design, development, and operation of the interface for laboratory investigation of this program is documented. The interface, architecturally based on the Intel 8751 microcontroller, is an interrupt-driven system designed to receive a digital message from an ultrareliable fault-tolerant control system (UFTCS). The interface links the UFTCS to an electronic servo-control unit, which controls a set of hydraulic actuators. It was necessary to build a UFTCS emulator (also based on the Intel 8751) to provide signal sources for testing the equipment.

  8. Measurement of Work Hardening Behavior of Pure Titanium Sheet Using A Servo-Controlled Tube Bulge Testing Apparatus

    SciTech Connect

    Sumita, Takeshi; Kuwabara, Toshihiko; Hayashida, Yasuhiro

    2011-05-04

    Biaxial stress tests of rolled pure titanium sheet (JIS 1, 0.5 mm thick) have been carried out in order to investigate the anisotropic plastic deformation under biaxial tension. Rolled pure titanium sheet was bent and welded to make tubular specimens. Combined tension-internal pressure was applied to the tubular specimens using the servo-controlled tube bulge testing apparatus developed by one of the authors [Kuwabara, T., Yoshida, K., Narihara, K., Takahashi S., Int. J. Plasticity 21 (1), 101-117 (2002)], so that the strain rate ratio, {epsilon}{sub {phi}}:{epsilon}{theta}, in the axial ({phi}) and circumferential ({theta}) directions of the specimen was controlled to be constant. Contours of plastic work at different levels of plastic strain and stress paths under constant strain rate ratios have been observed in the first quadrant of stress space. It is found that the test material exhibits significant differential work hardening behavior with the increase of plastic work.

  9. Measurement of Work Hardening Behavior of Pure Titanium Sheet Using A Servo-Controlled Tube Bulge Testing Apparatus

    NASA Astrophysics Data System (ADS)

    Sumita, Takeshi; Kuwabara, Toshihiko; Hayashida, Yasuhiro

    2011-05-01

    Biaxial stress tests of rolled pure titanium sheet (JIS ♯1, 0.5 mm thick) have been carried out in order to investigate the anisotropic plastic deformation under biaxial tension. Rolled pure titanium sheet was bent and welded to make tubular specimens. Combined tension-internal pressure was applied to the tubular specimens using the servo-controlled tube bulge testing apparatus developed by one of the authors [Kuwabara, T., Yoshida, K., Narihara, K., Takahashi S., Int. J. Plasticity 21 (1), 101-117 (2002)], so that the strain rate ratio, ɛ˙φ:ɛ˙θ, in the axial (φ) and circumferential (θ) directions of the specimen was controlled to be constant. Contours of plastic work at different levels of plastic strain and stress paths under constant strain rate ratios have been observed in the first quadrant of stress space. It is found that the test material exhibits significant differential work hardening behavior with the increase of plastic work.

  10. Faulting of rocks in three-dimensional strain fields I. Failure of rocks in polyaxial, servo-control experiments

    USGS Publications Warehouse

    Reches, Z.; Dieterich, J.H.

    1983-01-01

    The dependence of the number of sets of faults and their orientation on the intermediate strain axis is investigated through polyaxial tests, reported here, and theoretical analysis, reported in an accompanying paper. In the experiments, cubic samples of Berea sandstone, Sierra-White and Westerly granites, and Candoro and Solnhofen limestones were loaded on their three pairs of faces by three independent, mutually perpendicular presses at room temperature. Two of the presses were servo-controlled and applied constant displacement rates throughout the experiment. Most samples display three or four sets of faults in orthorhombic symmetry. These faults form in several yielding events that follow a stage of elastic deformation. In many experiments, the maximum and the intermediate compressive stresses interchange orientations during the yielding events, where the corresponding strains are constant. The final stage of most experiments is characterized by slip along the faults. ?? 1983.

  11. WITHDRAWN: Complex Study of Transport AC Loss in Various 2G HTS Racetrack Coils

    NASA Astrophysics Data System (ADS)

    Chen, Yiran; Zhang, Min; Chudy, Michal; Matsuda, Koichi; Coombs, Tim

    2013-06-01

    HTS racetrack coils are becoming important elements of an emerging number of superconducting devices such as generators or motors. In these devices the issue of AC loss is crucial, as performance and cooling power are derived from this quantity. This paper presents a comparative study of transport AC loss in two different types of 2G HTS racetrack coils. In this study, both experimental measurements and computer simulation approaches were employed. All the experiments were performed using classical AC electrical method. The finite-element computer model was used to estimate electromagnetic properties and calculate transport AC loss. The main difference between the characterized coils is covered inside tape architectures. While one coil uses tape based on RABITS magnetic substrate, the second coil uses a non-magnetic tape. Ferromagnetic loss caused by a magnetic substrate is an important issue involved in the total AC loss. As a result, the coil with the magnetic substrate surprised with high AC loss and rather low performance.

  12. Complex study of transport AC loss in various 2G HTS racetrack coils

    NASA Astrophysics Data System (ADS)

    Chen, Yiran; Zhang, Min; Chudy, Michal; Matsuda, Koichi; Coombs, Tim

    2013-04-01

    HTS racetrack coils are becoming important elements of an emerging number of superconducting devices such as generators or motors. In these devices the issue of AC loss is crucial, as performance and cooling power are derived from this quantity. This paper presents a comparative study of transport AC loss in two different types of 2G HTS racetrack coils. In this study, both experimental measurements and computer simulation approaches were employed. All the experiments were performed using classical AC electrical method. The finite-element computer model was used to estimate electromagnetic properties and calculate transport AC loss. The main difference between the characterized coils is covered inside tape architectures. While one coil uses tape based on RABITS magnetic substrate, the second coil uses a non-magnetic tape. Ferromagnetic loss caused by a magnetic substrate is an important issue involved in the total AC loss. As a result, the coil with the magnetic substrate surprised with high AC loss and rather low performance.

  13. Comparison of the Unique Mobility and DOE-developed ac electric drive systems

    SciTech Connect

    Cole, G.H.

    1993-01-01

    A comparison was made between the most recent DOE-developed AC electric vehicle drive systems and that which is independently under development by Unique Mobility of Golden, Colorado. The DOE-developed AC systems compared in this study are the Single-Shaft Electric Propulsion System (ETX-II) developed by Ford Motor Company and the General Electric Company under contract number DE-AC07-85NV10418, the Dual-Shaft Electric Propulsion (DSEP) System developed by Eaton Corporation under contract number DOE-AC08-84NV-10366, and the anticipated results of the Modular Electric Vehicle (MEV) system currently being developed by Ford and General Electric under contract number DE-AC07-90ID13019. The Unique Mobility brushless DC electric vehicle drive system represents their latest electric drive technology and is being developed in cooperation with BMW Technik Gmbh of Germany. Comparisons of specific volume, specific weight, efficiency and expected vehicle performance are made of the different systems based upon measured system performance data where available. One conclusion presented is that the Unique Mobility drive system under development with BMW appears to provide comparable performance to the AC systems studied.

  14. Voltage controller/current limiter for ac

    NASA Technical Reports Server (NTRS)

    Wu, T. T.

    1980-01-01

    Circuit protects ac power systems for overload failures, limits power surge and short-circuit currents to 150 percent of steady state level, regulates ac output voltage, and soft starts loads. Limiter generates dc error signal in response to line fluctuations and dumps power when overload is reached. Device is inserted between ac source and load.

  15. Development of a computer algorithm for the analysis of variable-frequency AC drives: Case studies included

    NASA Technical Reports Server (NTRS)

    Kankam, M. David; Benjamin, Owen

    1991-01-01

    The development of computer software for performance prediction and analysis of voltage-fed, variable-frequency AC drives for space power applications is discussed. The AC drives discussed include the pulse width modulated inverter (PWMI), a six-step inverter and the pulse density modulated inverter (PDMI), each individually connected to a wound-rotor induction motor. Various d-q transformation models of the induction motor are incorporated for user-selection of the most applicable model for the intended purpose. Simulation results of selected AC drives correlate satisfactorily with published results. Future additions to the algorithm are indicated. These improvements should enhance the applicability of the computer program to the design and analysis of space power systems.

  16. Comparison of effects of transcranial magnetic stimulation on primary motor cortex and supplementary motor area in motor skill learning (randomized, cross over study).

    PubMed

    Kim, Yong Kyun; Shin, Sung Hun

    2014-01-01

    Motor skills require quick visuomotor reaction time, fast movement time, and accurate performance. Primary motor cortex (M1) and supplementary motor area (SMA) are closely related in learning motor skills. Also, it is well known that high frequency repeated transcranial magnetic stimulation (rTMS) on these sites has a facilitating effect. The aim of this study was to compare the effects of high frequency rTMS activation of these two brain sites on learning of motor skills. Twenty three normal volunteers participated. Subjects were randomly stimulated on either brain area, SMA or M1. The motor task required the learning of sequential finger movements, explicitly or implicitly. It consisted of pressing the keyboard sequentially with their right hand on seeing 7 digits on the monitor explicitly, and then tapping the 7 digits by memorization, implicitly. Subjects were instructed to hit the keyboard as fast and accurately as possible. Using Musical Instrument Digital Interface (MIDI), the keyboard pressing task was measured before and after high frequency rTMS for motor performance, which was measured by response time (RT), movement time, and accuracy (AC). A week later, the same task was repeated by cross-over study design. At this time, rTMS was applied on the other brain area. Two-way ANOVA was used to assess the carry over time effect and stimulation sites (M1 and SMA), as factors. Results indicated that no carry-over effect was observed. The AC and RT were not different between the two stimulating sites (M1 and SMA). But movement time was significantly decreased after rTMS on both SMA and M1. The amount of shortened movement time after rTMS on SMA was significantly increased as compared to the movement time after rTMS on M1 (p < 0.05), especially for implicit learning of motor tasks. The coefficient of variation was lower in implicit trial than in explicit trial. In conclusion, this finding indicated an important role of SMA compared to M1, in implicit motor

  17. Electrospray mass spectrometry of NeuAc oligomers associated with the C fragment of the tetanus toxin

    SciTech Connect

    Prieto, M C; Whittal, R M; Baldwin, M A; Burlingame, A L; Balhorn, R

    2005-04-03

    The Clostridial neurotoxins, botulinum and tetanus, gain entry into neuronal cells by protein recognition involving cell specific binding sites. The sialic or N-acetylneuraminic acid (NeuAc) residues of gangliosides attached to the surface of motor neurons are the suspected recognition and interaction points with Clostridial neurotoxins, although not necessarily the only ones. We have used electrospray ionization mass spectrometry (ESIMS) to examine formation of complexes between the tetanus toxin C fragment, or targeting domain, and carbohydrates containing NeuAc groups to determine how NeuAc residues contribute to ganglioside binding. ESI-MS was used to rapidly and efficiently measure dissociation constants for a number of related NeuAc-containing carbohydrates and NeuAc oligomers, information that has helped identify the structural features of gangliosides that determine their binding to tetanus toxin. The strength of the interactions between the C fragment and (NeuAc){sub n}, are consistent with the topography of the targeting domain of tetanus toxin and the nature of its carbohydrate binding sites. The results suggest that the targeting domain of tetanus toxin contains two binding sites that can accommodate NeuAc (or a dimer). This study also shows that NeuAc must play an important role in ganglioside binding and molecular recognition, a process critical for normal cell function and one frequently exploited by toxins, bacteria and viruses to facilitate their entrance into cells.

  18. Motor Priming in Neurorehabilitation

    PubMed Central

    Stoykov, Mary Ellen; Madhavan, Sangeetha

    2014-01-01

    Priming is a type of implicit learning wherein a stimulus prompts a change in behavior. Priming has been long studied in the field of psychology. More recently, rehabilitation researchers have studied motor priming as a possible way to facilitate motor learning. For example, priming of the motor cortex is associated with changes in neuroplasticity that are associated with improvements in motor performance. Of the numerous motor priming paradigms under investigation, only a few are practical for the current clinical environment, and the optimal priming modalities for specific clinical presentations are not known. Accordingly, developing an understanding of the various types of motor priming paradigms and their underlying neural mechanisms is an important step for therapists in neurorehabilitation. Most importantly, an understanding of the methods and their underlying mechanisms is essential for optimizing rehabilitation outcomes. The future of neurorehabilitation is likely to include these priming methods, which are delivered prior to or in conjunction with primary neurorehabilitation therapies. In this Special Interest article we discuss those priming paradigms that are supported by the greatest amount of evidence including: (i) stimulation-based priming, (ii) motor imagery and action observation, (iii) sensory priming, (iv) movement-based priming, and (v) pharmacological priming. PMID:25415551

  19. High-vibration detection using motor current signature analysis

    SciTech Connect

    Castleberry, K.N.

    1996-08-01

    Motor current signature analysis (CSA) has been used for several years as a diagnostic tool for electrical problems in ac, induction motors. Personnel at Oak Ridge National Laboratory have found that CSA can also provide information about system vibrations and imbalances similar to the information provided by an accelerometer. As a result, CSA techniques for monitoring the status of the equipment, such as pumps and compressors, driven by induction motors have been developed and used in dedicated monitoring systems. In this work, researchers have found that CSA responds proportionately to imbalances in rotating equipment and can be used to detect the In high-vibration conditions that can result. This report describes how vibration monitoring with CSA can be implemented and presents test data to support that use.

  20. The induction motor

    NASA Astrophysics Data System (ADS)

    Redinz, José Arnaldo

    2015-09-01

    We obtain analytical expressions for the torques and angular speed of an induction motor with a simple geometry, resembling the geometry of the first induction motor investigated by Arago in 1824. The rotor is a conducting disc rotating between the magnetic poles of two off-axis solenoids, displaced in space by 90^\\circ from each other. We apply our results to discuss a theory for the ubiquitous electromechanical watt-hour meter. For comparison of the theoretical result for the angular speed with measurements, we propose a simple experiment in which an induction motor with an aluminum disc rotor is constructed.

  1. Adaptive PIF Control for Permanent Magnet Synchronous Motors Based on GPC

    PubMed Central

    Lu, Shaowu; Tang, Xiaoqi; Song, Bao

    2013-01-01

    To enhance the control performance of permanent magnet synchronous motors (PMSMs), a generalized predictive control (GPC)-based proportional integral feedforward (PIF) controller is proposed for the speed control system. In this new approach, firstly, based on the online identification of controlled model parameters, a simplified GPC law supplies the PIF controller with suitable control parameters according to the uncertainties in the operating conditions. Secondly, the speed reference curve for PMSMs is usually required to be continuous and continuously differentiable according to the general servo system design requirements, so the adaptation of the speed reference is discussed in details in this paper. Hence, the performance of the speed control system using a GPC-based PIF controller is improved for tracking some specified signals. The main motivation of this paper is the extension of GPC law to replace the traditional PI or PIF controllers in industrial applications. The efficacy and usefulness of the proposed controller are verified through experimental results. PMID:23262481

  2. Implementation of Robot Finger Using Shape Memory Alloys and Electrical Motors

    NASA Astrophysics Data System (ADS)

    Terauchi, Mina; Zenba, Kota; Shimada, Akira

    This paper introduces a mechanical structure and control technique of a second robot finger as a system integration. The finger has been developed as element of a robot hand which has 20 joints and 16 degrees of freedom in order to express fingerspelling. The first joint of the finger is driven by small DC servo motor and the second and third joints are driven by shape-memory alloy (SMA) wires. The hand system consists of four parts of “hand mechanism”, “drive device”, “control unit” and “man-machine interface”. In order to implement cooperative smooth motions, the control system is designed based on experimental results related to system identification, and the position trajectory refernce is designed considering time delay on the SMA. Finally, we report the simulation and experimental control results to evaluate the presented system.

  3. A Simple Design Method Based on Vector Control of AC Machines with LC Filter

    NASA Astrophysics Data System (ADS)

    Saito, Ryosuke; Kubota, Hisao

    This paper presents a simple voltage control system of AC machines using PWM voltage source inverter with output LC filters. By assuming a motor as a current source, the voltage is controlled by a simple proportional differential (PD) control. The vector control and PD control can be separately controlled in this system. A method for disturbance rejection is also described. The effectiveness of the proposed method is verified by simulations and experiments.

  4. Simultaneous distribution of AC and DC power

    DOEpatents

    Polese, Luigi Gentile

    2015-09-15

    A system and method for the transport and distribution of both AC (alternating current) power and DC (direct current) power over wiring infrastructure normally used for distributing AC power only, for example, residential and/or commercial buildings' electrical wires is disclosed and taught. The system and method permits the combining of AC and DC power sources and the simultaneous distribution of the resulting power over the same wiring. At the utilization site a complementary device permits the separation of the DC power from the AC power and their reconstruction, for use in conventional AC-only and DC-only devices.

  5. ac-resistance-measuring instrument

    SciTech Connect

    Hof, P.J.

    1981-04-22

    An auto-ranging ac resistance measuring instrument for remote measurement of the resistance of an electrical device or circuit connected to the instrument includes a signal generator which generates an ac excitation signal for application to a load, including the device and the transmission line, a monitoring circuit which provides a digitally encoded signal representing the voltage across the load, and a microprocessor which operates under program control to provide an auto-ranging function by which range resistance is connected in circuit with the load to limit the load voltage to an acceptable range for the instrument, and an auto-compensating function by which compensating capacitance is connected in shunt with the range resistance to compensate for the effects of line capacitance.

  6. A study of some features of ac and dc electric power systems for a space station

    NASA Technical Reports Server (NTRS)

    Hanania, J. I.

    1983-01-01

    This study analyzes certain selected topics in rival dc and high frequency ac electric power systems for a Space Station. The interaction between the Space Station and the plasma environment is analyzed, leading to a limit on the voltage for the solar array and a potential problem with resonance coupling at high frequencies. Certain problems are pointed out in the concept of a rotary transformer, and further development work is indicated in connection with dc circuit switching, special design of a transmission conductor for the ac system, and electric motors. The question of electric shock hazards, particularly at high frequency, is also explored. and a problem with reduced skin resistance and therefore increased hazard with high frequency ac is pointed out. The study concludes with a comparison of the main advantages and disadvantages of the two rival systems, and it is suggested that the choice between the two should be made after further studies and development work are completed.

  7. Zigzag Connected Autotransformer-Based 24-pulse AC-DC Converter

    NASA Astrophysics Data System (ADS)

    Xiao-qiang, Chen; Hao, Qiu

    2015-02-01

    In this paper, a zigzag connected autotransformer-based 24-pulse AC-DC converter is designed, modeled and simulated to feed direct torque controlled induction motor drives. Winding arrangements and parameters of the autotransformer and interphase reactor are given. Moreover, the design procedure of the autotransformer is modified to make it suitable for retrofit applications. Simulation results indicate that the system is capable of eliminating up to 21st harmonics in the ac mains current. The effect of load variation and load character is also studied to demonstrate the performance and effectiveness of the proposed 24-pulse converters. A set of power quality indices at ac mains and dc side are presented to compare the performance of 6-, 12- and 24-pulse converters.

  8. System and method for motor parameter estimation

    SciTech Connect

    Luhrs, Bin; Yan, Ting

    2014-03-18

    A system and method for determining unknown values of certain motor parameters includes a motor input device connectable to an electric motor having associated therewith values for known motor parameters and an unknown value of at least one motor parameter. The motor input device includes a processing unit that receives a first input from the electric motor comprising values for the known motor parameters for the electric motor and receive a second input comprising motor data on a plurality of reference motors, including values for motor parameters corresponding to the known motor parameters of the electric motor and values for motor parameters corresponding to the at least one unknown motor parameter value of the electric motor. The processor determines the unknown value of the at least one motor parameter from the first input and the second input and determines a motor management strategy for the electric motor based thereon.

  9. Functional connectivity underlying postural motor adaptation in people with multiple sclerosis

    PubMed Central

    Fling, Brett W.; Gera Dutta, Geetanjali; Horak, Fay B.

    2015-01-01

    A well-characterized neural network is associated with motor learning, involving several brain regions known to have functional and structural deficits in persons with multiple sclerosis (PwMS). However, it is not known how MS affects postural motor learning or the neural networks involved. The aim of this study was to gain a better understanding of the neural networks underlying adaptation of postural responses within PwMS. Participants stood on a hydraulically driven, servo-controlled platform that translated horizontally forward and backward in a continuous sinusoidal pattern across multiple trials over two consecutive days. Our results show similar postural adaptation between PwMS and age-matched control participants despite overall deficits in postural motor control in PwMS. Moreover, PwMS demonstrated better retention the following day. PwMS had significantly reduced functional connectivity within both the cortico-cerebellar and cortico-striatal motor loops; neural networks that subserve implicit motor learning. In PwMS, greater connectivity strength within the cortico-cerebellar circuit was strongly related to better baseline postural control, but not to postural adaptation as it was in control participants. Further, anti-correlated cortico-striatal connectivity within the right hemisphere was related to improved postural adaptation in both groups. Taken together with previous studies showing a reduced reliance on cerebellar- and proprioceptive-related feedback control in PwMS, we suggest that PwMS may rely on cortico-striatal circuitry to a greater extent than cortico-cerebellar circuitry for the acquisition and retention of motor skills. PMID:26106552

  10. Functional connectivity underlying postural motor adaptation in people with multiple sclerosis.

    PubMed

    Fling, Brett W; Gera Dutta, Geetanjali; Horak, Fay B

    2015-01-01

    A well-characterized neural network is associated with motor learning, involving several brain regions known to have functional and structural deficits in persons with multiple sclerosis (PwMS). However, it is not known how MS affects postural motor learning or the neural networks involved. The aim of this study was to gain a better understanding of the neural networks underlying adaptation of postural responses within PwMS. Participants stood on a hydraulically driven, servo-controlled platform that translated horizontally forward and backward in a continuous sinusoidal pattern across multiple trials over two consecutive days. Our results show similar postural adaptation between PwMS and age-matched control participants despite overall deficits in postural motor control in PwMS. Moreover, PwMS demonstrated better retention the following day. PwMS had significantly reduced functional connectivity within both the cortico-cerebellar and cortico-striatal motor loops; neural networks that subserve implicit motor learning. In PwMS, greater connectivity strength within the cortico-cerebellar circuit was strongly related to better baseline postural control, but not to postural adaptation as it was in control participants. Further, anti-correlated cortico-striatal connectivity within the right hemisphere was related to improved postural adaptation in both groups. Taken together with previous studies showing a reduced reliance on cerebellar- and proprioceptive-related feedback control in PwMS, we suggest that PwMS may rely on cortico-striatal circuitry to a greater extent than cortico-cerebellar circuitry for the acquisition and retention of motor skills. PMID:26106552

  11. Piezoelectric Rotary Tube Motor

    NASA Technical Reports Server (NTRS)

    Fisher, Charles D.; Badescu, Mircea; Braun, David F.; Culhane, Robert

    2011-01-01

    A custom rotary SQUIGGLE(Registered TradeMark) motor has been developed that sets new benchmarks for small motor size, high position resolution, and high torque without gear reduction. Its capabilities cannot be achieved with conventional electromagnetic motors. It consists of piezoelectric plates mounted on a square flexible tube. The plates are actuated via voltage waveforms 90 out of phase at the resonant frequency of the device to create rotary motion. The motors were incorporated into a two-axis postioner that was designed for fiber-fed spectroscopy for ground-based and space-based projects. The positioner enables large-scale celestial object surveys to take place in a practical amount of time.

  12. Hybrid Rocket Motor Test

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Stennis Space Center conducts a test on a hybrid rocket motor fed by a liquid oxygen turbopump. The test occurred at the E-1 test facility. The test was believed to be the first of its kind in the world.

  13. Chronic motor tic disorder

    MedlinePlus

    Chronic motor tic disorder is more common than Tourette syndrome . Chronic tics may be forms of Tourette syndrome. Tics usually start at age 5 or 6 and get worse until age 12. They often improve during adulthood.

  14. Motor Vehicle Safety

    MedlinePlus

    ... these crashes is one part of motor vehicle safety. Here are some things you can do to ... speed or drive aggressively Don't drive impaired Safety also involves being aware of others. Share the ...

  15. MotorWeek

    ScienceCinema

    None

    2013-04-19

    In 2008, PBS's MotorWeek, television's original automotive magazine, visited Argonne's Transportation Technology R&D Center "to learn what it really takes to make clean power sources a viable reality."

  16. MotorWeek

    SciTech Connect

    2009-01-01

    In 2008, PBS's MotorWeek, television's original automotive magazine, visited Argonne's Transportation Technology R&D Center "to learn what it really takes to make clean power sources a viable reality."

  17. Booster separation motor

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The design, development, fabrication, testing, evaluation and flight qualification of the space shuttle booster separation motor is discussed. Delivery of flight hardware to support the research and development flights of the space shuttle is discussed.

  18. Electromechanical systems with transient high power response operating from a resonant AC link

    NASA Technical Reports Server (NTRS)

    Burrows, Linda M.; Hansen, Irving G.

    1992-01-01

    The combination of an inherently robust asynchronous (induction) electrical machine with the rapid control of energy provided by a high frequency resonant AC link enables the efficient management of higher power levels with greater versatility. This could have a variety of applications from launch vehicles to all-electric automobiles. These types of systems utilize a machine which is operated by independent control of both the voltage and frequency. This is made possible by using an indirect field-oriented control method which allows instantaneous torque control in all four operating quadrants. Incorporating the AC link allows the converter in these systems to switch at the zero crossing of every half cycle of the AC waveform. This zero loss switching of the link allows rapid energy variations to be achieved without the usual frequency proportional switching loss. Several field-oriented control systems were developed by LeRC and General Dynamics Space Systems Division under contract to NASA. A description of a single motor, electromechanical actuation system is presented. Then, focus is on a conceptual design for an AC electric vehicle. This design incorporates an induction motor/generator together with a flywheel for peak energy storage. System operation and implications along with the associated circuitry are addressed. Such a system would greatly improve all-electric vehicle ranges over the Federal Urban Driving Cycle (FUD).

  19. High Power Density Motors

    NASA Technical Reports Server (NTRS)

    Kascak, Daniel J.

    2004-01-01

    With the growing concerns of global warming, the need for pollution-free vehicles is ever increasing. Pollution-free flight is one of NASA's goals for the 21" Century. , One method of approaching that goal is hydrogen-fueled aircraft that use fuel cells or turbo- generators to develop electric power that can drive electric motors that turn the aircraft's propulsive fans or propellers. Hydrogen fuel would likely be carried as a liquid, stored in tanks at its boiling point of 20.5 K (-422.5 F). Conventional electric motors, however, are far too heavy (for a given horsepower) to use on aircraft. Fortunately the liquid hydrogen fuel can provide essentially free refrigeration that can be used to cool the windings of motors before the hydrogen is used for fuel. Either High Temperature Superconductors (HTS) or high purity metals such as copper or aluminum may be used in the motor windings. Superconductors have essentially zero electrical resistance to steady current. The electrical resistance of high purity aluminum or copper near liquid hydrogen temperature can be l/lOO* or less of the room temperature resistance. These conductors could provide higher motor efficiency than normal room-temperature motors achieve. But much more importantly, these conductors can carry ten to a hundred times more current than copper conductors do in normal motors operating at room temperature. This is a consequence of the low electrical resistance and of good heat transfer coefficients in boiling LH2. Thus the conductors can produce higher magnetic field strengths and consequently higher motor torque and power. Designs, analysis and actual cryogenic motor tests show that such cryogenic motors could produce three or more times as much power per unit weight as turbine engines can, whereas conventional motors produce only 1/5 as much power per weight as turbine engines. This summer work has been done with Litz wire to maximize the current density. The current is limited by the amount of heat it

  20. Motor Energy Conservation Measures

    2010-12-31

    This software requires inputs of simple motor inventory information and calculates the energy and cost benefits of various retrofit opportunities. This tool includes energy conservation measures for: High Efficiency Motor retrofit and Cogged V-belts retrofit. This tool calculates energy savings, demand reduction, cost savings, and building life cycle costs including: simple payback, discounted payback, net-present value, and savings to investment ratio. In addition this tool also displays the environmental benefits of a project.

  1. Rocket Motor Microphone Investigation

    NASA Technical Reports Server (NTRS)

    Pilkey, Debbie; Herrera, Eric; Gee, Kent L.; Giraud, Jerom H.; Young, Devin J.

    2010-01-01

    At ATK's facility in Utah, large full-scale solid rocket motors are tested. The largest is a five-segment version of the reusable solid rocket motor, which is for use on the Ares I launch vehicle. As a continuous improvement project, ATK and BYU investigated the use of microphones on these static tests, the vibration and temperature to which the instruments are subjected, and in particular the use of vent tubes and the effects these vents have at low frequencies.

  2. Transfer function verification and block diagram simplification of a very high-order distributed pole closed-loop servo by means of non-linear time-response simulation

    NASA Technical Reports Server (NTRS)

    Mukhopadhyay, A. K.

    1975-01-01

    Linear frequency domain methods are inadequate in analyzing the 1975 Viking Orbiter (VO75) digital tape recorder servo due to dominant nonlinear effects such as servo signal limiting, unidirectional servo control, and static/dynamic Coulomb friction. The frequency loop (speed control) servo of the VO75 tape recorder is used to illustrate the analytical tools and methodology of system redundancy elimination and high order transfer function verification. The paper compares time-domain performance parameters derived from a series of nonlinear time responses with the available experimental data in order to select the best possible analytical transfer function representation of the tape transport (mechanical segment of the tape recorder) from several possible candidates. The study also shows how an analytical time-response simulation taking into account most system nonlinearities can pinpoint system redundancy and overdesign stemming from a strictly empirical design approach. System order reduction is achieved through truncation of individual transfer functions and elimination of redundant blocks.

  3. Rationales for improving motor function.

    PubMed

    Hummelsheim, H

    1999-12-01

    New findings in basic neuroscience, and the growing knowledge regarding neuroplasticity and motor learning have exerted influence and have provided stimuli for motor rehabilitation research. Repeated motor practice has been identified as crucial for motor recovery. Further novel and scientifically based therapeutic approaches have been developed: constraint-induced movement therapy, electromyogram-initiated neuromuscular stimulation, motor imagery and music therapy are all discussed in the present review. PMID:10676751

  4. Project SUTOR Superconducting Speed-Controlled Torque Motor for 25.000Nm

    NASA Astrophysics Data System (ADS)

    Oswald, B.; de Waele, A. T. A. M.; Söll, M.; Reis, T.; Maier, T.; Oswald, J.; Teigelkötter, J.; Kowalski, T.

    SUTOR is a project that is supported by the german ministry of economy and technology (FKZ 0327866A). The partners working on this project are Oswald Elektromotoren and Hochschule Aschaffenburg. Oswald is responsible for the layout of the Motor and its cryostat. Together with the Hochschule Aschaffenburg, Oswald has build a number of coils to determine the loss rates of superconductors when used with AC current and in external, oscillating magnetic fields. These results are taken to proof the at Oswald developed calculations for superconducting motors. The Hochschule Aschaffenburg is measuring the loss rates in superconducting coils and builds an inverter to fit the special requests a motor has when running with superconducting wires. The aim of this project is to realize a high torque motor that has compared to conventional torque motors a lower volume and weight, a higher efficiency and an increased dynamic acceleration.

  5. A New Type of Motor: Pneumatic Step Motor

    PubMed Central

    Stoianovici, Dan; Patriciu, Alexandru; Petrisor, Doru; Mazilu, Dumitru; Kavoussi, Louis

    2011-01-01

    This paper presents a new type of pneumatic motor, a pneumatic step motor (PneuStep). Directional rotary motion of discrete displacement is achieved by sequentially pressurizing the three ports of the motor. Pulsed pressure waves are generated by a remote pneumatic distributor. The motor assembly includes a motor, gearhead, and incremental position encoder in a compact, central bore construction. A special electronic driver is used to control the new motor with electric stepper indexers and standard motion control cards. The motor accepts open-loop step operation as well as closed-loop control with position feedback from the enclosed sensor. A special control feature is implemented to adapt classic control algorithms to the new motor, and is experimentally validated. The speed performance of the motor degrades with the length of the pneumatic hoses between the distributor and motor. Experimental results are presented to reveal this behavior and set the expectation level. Nevertheless, the stepper achieves easily controllable precise motion unlike other pneumatic motors. The motor was designed to be compatible with magnetic resonance medical imaging equipment, for actuating an image-guided intervention robot, for medical applications. For this reason, the motors were entirely made of nonmagnetic and dielectric materials such as plastics, ceramics, and rubbers. Encoding was performed with fiber optics, so that the motors are electricity free, exclusively using pressure and light. PneuStep is readily applicable to other pneumatic or hydraulic precision-motion applications. PMID:21528106

  6. A New Type of Motor: Pneumatic Step Motor.

    PubMed

    Stoianovici, Dan; Patriciu, Alexandru; Petrisor, Doru; Mazilu, Dumitru; Kavoussi, Louis

    2007-02-01

    This paper presents a new type of pneumatic motor, a pneumatic step motor (PneuStep). Directional rotary motion of discrete displacement is achieved by sequentially pressurizing the three ports of the motor. Pulsed pressure waves are generated by a remote pneumatic distributor. The motor assembly includes a motor, gearhead, and incremental position encoder in a compact, central bore construction. A special electronic driver is used to control the new motor with electric stepper indexers and standard motion control cards. The motor accepts open-loop step operation as well as closed-loop control with position feedback from the enclosed sensor. A special control feature is implemented to adapt classic control algorithms to the new motor, and is experimentally validated. The speed performance of the motor degrades with the length of the pneumatic hoses between the distributor and motor. Experimental results are presented to reveal this behavior and set the expectation level. Nevertheless, the stepper achieves easily controllable precise motion unlike other pneumatic motors. The motor was designed to be compatible with magnetic resonance medical imaging equipment, for actuating an image-guided intervention robot, for medical applications. For this reason, the motors were entirely made of nonmagnetic and dielectric materials such as plastics, ceramics, and rubbers. Encoding was performed with fiber optics, so that the motors are electricity free, exclusively using pressure and light. PneuStep is readily applicable to other pneumatic or hydraulic precision-motion applications. PMID:21528106

  7. Pneumatic motor powered Thrust Vector Control (TVC) for liquid propelled launch vehicles

    NASA Astrophysics Data System (ADS)

    Malone, Mark C.; Evans, P. S.

    1992-02-01

    Recent studies performed for the Titan 4 launch vehicle indicate significant potential advantages in replacing the current stage 1 and 2 recirculating hydraulic TVC (thrust vector control) system with a PMA (pneumatic mechanical actuation) system. Some of the advantages of a PMA system over the recirculating hydraulic system include reduced part count and weight, reduced maintenance and life-cycle cost, and improved mission reliability. PMA technology, used in aircraft applications since the 1960s, is well suited in launch vehicle TVC applications where an existing pneumatic pressure source is available. A typical pneumatic motor TVC consists of a pneumatic power source, a dual rotor pneumatic motor, a gear box, a ball screw actuator, and the associated closed-loop servo-control elements. One key issue with implementing this mechanical approach is designing a TVC system to withstand large load transient disturbances during liquid engine starting. Hydraulic actuator transient loads have exceeded 60,000 lb(sub f) for a 30,000 lb(sub f) stall design actuator during ground starts of the Titan 3B, Stage 1 engine. A PMA TVC system must also withstand these start transients without imparting excessive reaction loads to the engine nozzle and thrust structure. Work completed to date with Martin Marietta to examine pneumatic motor powered TVC options and technology benefits is presented. The load transient issue is discussed along with potential solutions and the associated trades. General background on PMA technology and experience base is also presented.

  8. PM brushless DC motor drive with a new power converter topology

    SciTech Connect

    Krishnan, R.; Lee, S.

    1995-12-31

    With the growing potential for widespread use of permanent magnet brushless dc motor drives (hereafter referred to as PMBDC drives) in many low-cost applications such as in hvac, refrigerators, and freezers in houses and small velocity servos in process industries, it has become important to minimize the cost. One obvious place for cost reduction is in the cost of the inverter and its associated controller. With that perspective, a novel application of the converter topology for the PMBDC known as C-dump in the switched reluctance motor drives is proposed in this paper. The advantages and disadvantages of this topology vis-a-vis the conventional 3 phase H-bridge converter, are highlighted from the points of view of economy in switches, volt ampere rating, associated controller cost, and packaging. Design considerations for the PMBDC motor are derived for use with the proposed converter topology. The operational and design characteristics of this converter driven PMBDC drive are derived for four quadrant performance. Guidelines for the design of the proposed performance. Guidelines for the design of the proposed topology are derived and presented in the paper. Experimental results from a laboratory prototype are presented to validate the feasibility of the proposed PMBDC drive system.

  9. Advanced Ultra-High Speed Motor for Drilling

    SciTech Connect

    Impact Technologies LLC; University of Texas at Arlington

    2007-03-31

    ,000 rpm for every 30.48 cm (12 inches) of power section. Operating conditions are 300 voltage AC at the motor leads. Power voltage losses in the cables/wirelines to the motor(s) are expected to be about 10% for 5000 feet carrying 2 amperes. Higher voltages and better insulators can lower these losses and carry more amperes. Cutting elements for such high tip velocities are currently not available, consequently these motors will not be built at this time. However, 7.62 cm (3 inch) OD, low speed, PMSM radial electric motors based on this project design are being built under a 2006 Oklahoma Center for the Advancement of Science and Technology 'proof of concept' grant.

  10. Ac electrode diagnostics in ac-operated metal halide lamps

    NASA Astrophysics Data System (ADS)

    Luijks, G. M. J. F.; van Esveld, H. A.; Nijdam, S.; Weerdesteijn, P. A. M.

    2008-07-01

    A diagnostic technique is presented to determine the electrode work function in ac-operated metal halide lamps. The heart of the experimental set-up is a high-speed photodiode array detector, which is able to follow real-time variations of electrode tip temperature and near-electrode plasma emissions in ac-operated experimental YAG lamps, enabling discrimination between the anode and cathode effects. Electrode tip temperature ripples have been measured for 100 Hz square wave operation and simulated with an existing electrode model. By using the electrode work function as main fit parameter for the simulations it is found that the measured cooling effect of the electrode tip in a NaTlDy-iodide lamp is caused by a gas-phase emitter effect of Dy. It is concluded that Dy coverage of the electrode tip causes an effective work function reduction of 0.3 eV at 100 Hz square wave operation, considerably less than the 1.0 eV reduction measured earlier for dc operation.

  11. High-Speed Gap Servo Control for Solid-Immersion-Lens-Based Near-Field Recording System with a Flexible Optical Disk

    NASA Astrophysics Data System (ADS)

    Hwang, Hyunwoo; Kim, Jung-Gon; Song, Ki Wook; Park, Kyoung-Su; Park, No-cheol; Yang, Hyunseok; Rhim, Yoon-Chul; Park, Young-Pil

    2011-09-01

    Higher data storage capacities and higher data transfer rates will be required in next-generation information storage devices. However, there is a limit to the rotational speeds of conventional disk structures. Hence, conventional disks will not be able to achieve high data transfer rates of over 250 Mbps that is required for next-generation storage devices. To increase the data transfer rate of a disk, flexible optical disks have been studied with the goal of stable rotation at a high speed, using a stabilizer to reduce disk oscillations. If a flexible optical disk is implemented in a near-field recording (NFR) system, simultaneous high data transfer rates and high-density recording should be possible. In an NFR system, it is very important to maintain the gap between the solid immersion lens (SIL) and the disk at distances below tens of nanometers. In this study, to simultaneously achieve high data storage capacity and high data transfer rate, we propose an improved gap servo control system for an SIL-based NFR system with a flexible optical disk. To enable robust control at a high rotational speed, a repetitive controller was designed and applied to the NFR servo algorithm. In both simulation and experiment, the newly designed gap servo controller stably maintained the gap distance in the SIL-based NFR system using a flexible optical disk.

  12. Dynamic Response of Control Servo System Installed in NAES-Equipped SB2C-5 Airplane (BuAer No. 83135)

    NASA Technical Reports Server (NTRS)

    Smaus, Louis H.; Stewart, Elwood C.

    1950-01-01

    Dynamic--response measurements for various conditions of displacement and rate signal input, sensitivity setting, and simulated hinge moment were made of the three control-surface servo systems of an NAES-equipped remote-controlled airplane while on the ground. The basic components of the servo systems are those of the General Electric Company type G-1 autopilot using electrical signal. sources, solenoid-operated valves, and hydraulic pistons. The test procedures and difficulties are discussed, Both frequency and transient-response data, are presented and comparisons are made. The constants describing the servo system, the undamped natural frequency, and the damping ratio, are determined by several methods. The response of the system with the addition of airframe rate signal is calculated. The transfer function of the elevator surface, linkage, and cable system is obtained. The agreement between various methods of measurement and calculation is considered very good. The data are complete enough and in such form that they may be used directly with the frequency-response data of an airplane to predict the stability of the autopilot-airplane combination.

  13. Motor considerations for turbomachinery

    SciTech Connect

    Halfpap, R.F.; Brotherhood, R. )

    1995-02-01

    Customers who use large rotating equipment realize motors can be subjected to hostile environmental conditions, nonstandard voltage levels and a variety of load requirements. The motor specifications they write reflect this change and have become far more detailed. Too often in the past, when large projects were being organized and highly technical equipment purchased, induction motors were thought of as standard pieces of equipment not requiring much in the way of specialized design. High-speed compressor applications are good examples of the need for specific compressor torque characteristics and starting requirements to allow for proper motor design. Not only different compressor designs, but adjustments in compressor valves and changes in gas process conditions, can produce a diversity of speed-torque curves. Therefore, it is not practical for a motor designer to be told to assume a standard compressor load torque during acceleration. An example of compressor speed-torque curves illustrates this point. The paper also presents the example of centrifugal pumps to further illustrate the need for properly matching driver torque and power requirements.

  14. Magnetostrictive direct drive motor

    NASA Technical Reports Server (NTRS)

    Naik, Dipak; Dehoff, P. H.

    1991-01-01

    Highly magnetostrictive materials such as Tb.3Dy.7Fe2, commercially known as TERFENOL-D, have been used to date in a variety of devices such as high power actuators and linear motors. The larger magnetostriction available in twinned single crystal TERFENOL-D, approx. 2000 ppm at moderate magnetic field strengths, makes possible a new generation of magnetomechanical devices. NASA researchers are studying the potential of this material as the basis for a direct microstepping rotary motor with torque densities on the order of industrial hydraulics and five times greater than that of the most efficient, high power electric motors. Such a motor would be a micro-radian stepper, capable of precision movements and self-braking in the power-off state. Innovative mechanical engineering techniques are juxtaposed on proper magnetic circuit design to reduce losses in structural flexures, inertias, thermal expansions, eddy currents, and magneto-mechanical coupling, thus optimizing motor performance and efficiency. Mathematical models are presented, including magnetic, structural, and both linear and nonlinear dynamic calculations and simulations. In addition, test results on prototypes are presented.

  15. The AC photovoltaic module is here!

    NASA Astrophysics Data System (ADS)

    Strong, Steven J.; Wohlgemuth, John H.; Wills, Robert H.

    1997-02-01

    This paper describes the design, development, and performance results of a large-area photovoltaic module whose electrical output is ac power suitable for direct connection to the utility grid. The large-area ac PV module features a dedicated, integrally mounted, high-efficiency dc-to-ac power inverter with a nominal output of 250 watts (STC) at 120 Vac, 60 H, that is fully compatible with utility power. The module's output is connected directly to the building's conventional ac distribution system without need for any dc wiring, string combiners, dc ground-fault protection or additional power-conditioning equipment. With its advantages, the ac photovoltaic module promises to become a universal building block for use in all utility-interactive PV systems. This paper discusses AC Module design aspects and utility interface issues (including islanding).

  16. Micromachine Wedge Stepping Motor

    SciTech Connect

    Allen, J.J.; Schriner, H.K.

    1998-11-04

    A wedge stepping motor, which will index a mechanism, has been designed and fabricated in the surface rnicromachine SUMMiT process. This device has demonstrated the ability to index one gear tooth at a time with speeds up to 205 teeth/see. The wedge stepper motor has the following features, whi:h will be useful in a number of applications. o The ability to precisely position mechanical components. . Simple pulse signals can be used for operation. o Only 2 drive signals are requixed for operation. o Torque and precision capabilities increase with device size . The device to be indexed is restrained at all times by the wedge shaped tooth that is used for actuation. This paper will discuss the theory of operation and desi=m of the wedge stepping motor. The fabrication and testing of I he device will also be presented.

  17. Rocket motor aeroacoustics

    NASA Astrophysics Data System (ADS)

    Hegde, U. G.; Strahle, W. C.

    1983-10-01

    Vibration problems in solid propellant rocket motors are investigated. A class of interior flows modelled to simulate flow conditions inside rocket motor cavities is considered. Turbulence generated pressure fluctuations are shown to consist of two components - acoustic and hydrodynamics. The Bernoulli enthalpy theory of aeroacoustics is employed to extract acoustic pressure spectra from experimentally obtained turbulence data and acoustic impedance values at flow boundaries. The effects of turbulence intensities, sidewall acoustic impedance, axial mass blowing distribution, length to diameter ratio of the cavity and different mass flux on the acoustic pressure level are investigated. Typical pressure levels, under rocket motor conditions, are calculated using the A/B model of propellant response. Estimates of the hydrodynamic component of the pressure fluctuation are provided for the case of fully developed turbulent pipe flow terminated by a choked nozzle.

  18. Bent shaft motor

    DOEpatents

    Benavides, G.L.

    1998-05-05

    A nonelectromagnetic motor comprising a base, a bent shaft which is rotatable relative to the base wherein the bent shaft comprises a straight portion aligned with a main axis and an offset portion that is offset with respect to the main axis; and a drive means for driving the offset portion of the bent shaft along a generally circular path in a plane perpendicular to the main axis to rotate the bent shaft. The bent shaft and drive means for driving the bent shaft can be selected from piezoelectric, magnetostrictive, rheological and shape memory alloys. The drive means of the nonelectromagnetic motor can additionally comprise a shell which shell surrounds and houses the bent shaft and precesses or gyrates which in turn causes the bent drive shaft to rotate. The nonelectromagnetic motor does not rely on friction for the application of torque upon a rotor. 11 figs.

  19. Magnetostrictive direct drive motors

    NASA Technical Reports Server (NTRS)

    Naik, Dipak; Dehoff, P. H.

    1990-01-01

    Developing magnetostrictive direct drive research motors to power robot joints is discussed. These type motors are expected to produce extraordinary torque density, to be able to perform microradian incremental steps and to be self-braking and safe with the power off. Several types of motor designs have been attempted using magnetostrictive materials. One of the candidate approaches (the magnetostrictive roller drive) is described. The method in which the design will function is described as is the reason why this approach is inherently superior to the other approaches. Following this, the design will be modelled and its expected performance predicted. This particular candidate design is currently undergoing detailed engineering with prototype construction and testing scheduled for mid 1991.

  20. Bent shaft motor

    DOEpatents

    Benavides, Gilbert L.

    1998-01-01

    A nonelectromagnetic motor comprising a base, a bent shaft which is rotable relative to the base wherein the bent shaft comprises a straight portion aligned with a main axis and an offset portion that is offset with respect to the main axis; and a drive means for driving the offset portion of the bent shaft along a generally circular path in a plane perpendicular to the main axis to rotate the bent shaft. The bent shaft and drive means for driving the bent shaft can be selected from piezoelectric, magnetostrictive, rheological and shape memory alloys. The drive means of the nonelectromagnetic motor can additionally comprise a shell which shell surrounds and houses the bent shaft and precesses or gyrates which in turn causes the bent drive shaft to rotate. The nonelectromagnetic motor does not rely on friction for the application of torque upon a rotor.