• Title/Summary/Keyword: Position estimator

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Robust Control for Nonlinear Friction Servo System Using Fuzzy Neural Network and Robust Friction State Observer (퍼지신경망과 강인한 마찰 상태 관측기를 이용한 비선형 마찰 서보시스템에 대한 강인 제어)

  • Han, Seong-Ik
    • Journal of the Korean Society for Precision Engineering
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    • v.25 no.12
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    • pp.89-99
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    • 2008
  • In this paper, the position tracking control problem of the servo system with nonlinear dynamic friction is issued. The nonlinear dynamic friction contains a directly immeasurable friction state variable and the uncertainty caused by incomplete parameter modeling and its variations. In order to provide the efficient solution to these control problems, we propose the composite control scheme, which consists of the robust friction state observer, the FNN approximator and the approximation error estimator with sliding mode control. In first, the sliding mode controller and the robust friction state observer is designed to estimate the unknown internal state of the LuGre friction model. Next, the FNN estimator is adopted to approximate the unknown lumped friction uncertainty. Finally, the adaptive approximation error estimator is designed to compensate the approximation error of the FNN estimator. Some simulations and experiments on the servo system assembled with ball-screw and DC servo motor are presented. Results show the remarkable performance of the proposed control scheme. The robust friction state observer can successfully identify immeasurable friction state and the FNN estimator and adaptive approximation error estimator give the robustness to the proposed control scheme against the uncertainty of the friction parameters.

A BLUE Estimator for Passive Localization by TDOA Method (TDOA 방식 기반 위치 추정을 위한 BLUE 추정기)

  • Lee, Young-Kyu;Yang, Sung-Hoon;Kwon, Taeg-Yong;Lee, Chang-Bok;Park, Byung-Koo;Lee, Won-Jin
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.11C
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    • pp.702-711
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    • 2011
  • In this paper, we derived a closed-form equation of a Best Linear Unbiased Estimator (BLUE) and its Crammer-Rao Lower Bound (CRLB) for the estimation of the position of the emitter based on the Time Difference of Arrival (TDOA) teclmique. The BLUE and CRLB were derived for the case of estimating 2 dimensional position of the emitter with 3 base stations or sensors, and for this purpose, we nsed an approximated equation of the TDOA hyperbola equation obtained from the first order Taylor-series after setting the reference points of the position. The derived equation can be used for any kind of noises which are uncorrelated in each other in the TOA measurement noises and for a white Gaussian noise also.

Sensorless Control of a Surface Mounted PM Synchronous Motor in Over Modulation Regions by Detecting Phase Voltages (영구자석 표면부착형 동기전동기의 과변조 영역에서 상전압 검출에 의한 센서리스 제어)

  • Choi, Hae-Jun;Lee, Han-Sol;Cho, Kwan-Yuhl;Kim, Hag-Wone
    • The Transactions of the Korean Institute of Power Electronics
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    • v.22 no.1
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    • pp.53-59
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    • 2017
  • The information on the actual voltages and actual currents of the motor is required for the sensorless control of a permanent magnet synchronous motor without rotor position sensors. In the model-based rotor position estimator of a PM synchronous motor, the reference voltages, which are the outputs of the current controller, are commonly used. The reference voltages in over-modulation regions for high-speed operation differ from the actual voltages applied to the motor. Consequently, the estimated rotor position and rotor speed may fail to track the real rotor position and real rotor speed. In this paper, the sensorless control for a PM synchronous motor in over-modulation regions for high-speed operation is proposed. The three-phase voltages applied to the motor are measured by using additional voltage detection circuits, and the performance of the rotor position estimator based on the measured three-phase voltages is validated through the experimental results.

A High-Performance Control System of Reluctance Synchronous Motor with Direct Torque Control (직접토크제어에 의한 리럭턴스 동기전동기의 고성능 제어시스템)

  • Kim, Min-Huei;Kim, Nam-Hun;Kim, Min-Ho
    • Proceedings of the KIEE Conference
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    • 2001.07e
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    • pp.47-52
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    • 2001
  • This paper presents a high-performance control system for Reluctance Synchronous Motor (RSM) drives with direct torque control (DTC). The system consist of stator flux observer, rotor position/speed estimator, torque estimator, two hysteresis band controllers, an optimal switching look-up table, IGBT voltage source inverter, and F240/C31DSP controller by using fully integrated control software. The stator flux observer is based on the combined voltage and current model with stator flux feedback adaptive control that inputs are current and voltage sensing of motor terminal with estimated rotor angle for wide speed range. The rotor position is estimated by the observed stator flux-linkage space vector. The estimated rotor speed can be determinated by differentiation of the rotor position used only in the current model part of the flux observer for a low speed operating area. To prove the suggested control algorithm, we have a simulation and testing at actual experimental system. The developed digitally high-performance position sensorless control system are shown a good motion control response characteristic results and high performance features using 1.0Kw RSM.

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Implementation of a Senseless Position Controller Capable of Multi-turn Detection in a Turret Servo System (터렛 서보 시스템에서 멀티-턴 검출이 가능한 센서리스 위치제어기 구현)

  • Cho, Nae-Soo
    • The Journal of the Korea institute of electronic communication sciences
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    • v.16 no.1
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    • pp.37-44
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    • 2021
  • This study is implemented as a sensor-less position controller capable of multi-turn detection to replace the expensive absolute encoder used in the turret servo system. For sensor-less control, the position information of the rotor is essential. For this, a magnetic flux estimator was implemented from the mathematical model of IPMSM used in the turret servo system. The position of the rotor and the angular velocity of the rotor were obtained using the rotor magnetic flux calculated from the magnetic flux estimator. Using the zero-crossing technique, one pulse was generated for each rotation of the estimated rotor magnetic flux to measure the number of multi-turns. Simulation and experiment results confirmed the usefulness of the proposed method.

Sensorless Speed Control of IPMSM Using Unscented Kalman Filter (엔센티드 칼만필터를 이용한 IPMSM의 센서리스 속도제어)

  • Jeon, Yong-Ho
    • The Journal of the Korea institute of electronic communication sciences
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    • v.8 no.12
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    • pp.1865-1874
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    • 2013
  • In this paper, a design method of speed and position estimator based on unscented Kalman filter is proposed for the no sensor control of IPMSM(Interior Permanent Magnet Synchronous Motor). The proposed method is simple more than the estimator designed with rotation axis for current measurement. Also the proposed state estimator is designed including nonlinear terms of the estimator. The controller which constructed using nonlinear back-stepping control method is operated speed and current control using the estimated speed and currents information. Through simulation, the performance of the designed estimator is compared to the estimator which is designed to synchronize d-q axis.

Design of Sliding Mode Controller with New Perturbation Estimator (새로운 섭동 추정기를 갖는 슬라이딩 모드 제어기의 설계)

  • Ham, Joon-Ho;Choi, Seung-Bok
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.782-787
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    • 2004
  • In the conventional sliding mode control technique, a priori knowledge of the bound of external disturbances or/and parameter uncertainties is required to assure control robustness. This, however, may not be easy to obtain in practical situation. This work presents a novel methodology, a sliding mode controller with perturbation estimator, which offers a robust control performance without a priori knowledge about the perturbations (disturbances and parameter uncertainties). The proposed technique is featured by an integrated average value of the imposed perturbation over a certain sampling period. This work also proposes two effective actuating methods of the perturbation estimator: on-off condition and filtering condition. In order to demonstrate the effectiveness of the proposed methodology, a two-link robotic system is adopted and its position control performance is evaluated. In addition, a comparative work between the conventional technique and the proposed one is undertaken.

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Noise and Fault Diagnosis Using Control Theory

  • Park, Rai-Wung;Sul Cho
    • Transactions on Control, Automation and Systems Engineering
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    • v.2 no.1
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    • pp.24-30
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    • 2000
  • The aim of this paper is to describe an advanced method of the fault diagnosis using Control Theory with reference to a crack detection, a new way to localize the crack position under influence of the plant disturbance and white measurement noise on a rotating shaft. As the first step, the shaft is physically modelled with a finite element method as usual and the dynamic mathematical model is derived from it using the Hamilton-principle and in this way the system is modelled by various subsystems. The equations of motions with a crack are established by the adaption of the local stiffness change through breathing and gaping[1] from the crack to the equation of motion with an undamaged shaft. This is supposed to be regarded as a reference system for the given system. Based on the fictitious model of the time behaviour induced from vibration phenomena measured at the bearings, a nonlinear state observer is designed in order to detect the crack on the shaft. This is the elementary NL-observer(EOB). Using the elementary observer, an Estimator(Observer Bank) is established and arranged at the certain position on the shaft. In case, a crack is found and its position is known, the procedure, fro the estimation of the depth is going to begin.

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A Design of Adaptive Controller with Nonlinear Dynamic Friction Compensator for Precise Position Control of Linear Motor System (선형모터 정밀 위치제어를 위한 비선형 동적 마찰력 보상기를 갖는 적응 제어기 설계)

  • Lee, Jin-Woo;Cho, Hyun-Cheol;Lee, Young-Jin;Lee, Kwom-Soon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.5
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    • pp.944-957
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    • 2007
  • In general mechanical servo systems, friction deteriorates the performance of controllers by its nonlinear characteristics. Especially, friction phenomenon causes steady-state tracking errors and limit cycles in position and velocity control systems, even though gains of controllers are tuned well in linear system model. Even if sensor is used higher accuracy level, it is difficult to improve tracking performance of the position to the same level with a general control method such as PID type. Therefore, many friction models were proposed and compensation methods have been researched actively. In this paper, we consider that the variation of mover's mass is various by loading and unloading. The normal force variation occurs by it and other parameters. Therefore, the proposed control system is composed of main position controller and a friction compensator. A parameter estimator for a nonlinear friction model is designed by adaptive control law and adaptive backstopping control method.

Compensation of Periodic Magnetic Saturation Effects for the High-Speed Sensorless Control of PMSM Driven by Inverter Output Power Control-based PFC Strategy

  • Lee, Kwang-Woon
    • Journal of Power Electronics
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    • v.15 no.5
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    • pp.1264-1273
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    • 2015
  • An inverter output power control based power factor correction (PFC) strategy is being extensively used for permanent magnet synchronous motor (PMSM) drives in appliances because such a strategy can considerably reduce the cost and size of the inverter. In this strategy, PFC circuits are removed and large electrolytic DC-link capacitors are replaced with small film capacitors. In this application, the PMSM d-q axes currents are controlled to produce ripples, the frequency of which is twice that of the AC main voltage, to obtain a high power factor at the AC mains. This process indicates that the PMSM operates under periodic magnetic saturation conditions. This paper proposes a back electromotive-force (back-EMF) estimator for the high-speed sensorless control of PMSM operating under periodic magnetic saturation conditions. The transfer function of the back-EMF estimator is analyzed to examine the effect of the periodic magnetic saturation on the accuracy of the estimated rotor position. A simple compensation method for the estimated position errors caused by the periodic magnetic saturation is also proposed in this paper. The effectiveness of the proposed method is experimentally verified with the use of a PMSM drive for a vacuum cleaner centrifugal fan, wherein the maximum operating speed reaches 30,000 rpm.