• Title/Summary/Keyword: Feedforward-feedback 제어

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A Design Of Active Vibration Control System For Precise Maglev Stage (초정밀 자기부상 스테이지용 능동진동제어시스템 설계)

  • Lee, Joo-Hoon;Kim, Yong-Joo;Son, Sung-Wan;Lee, Hong-Ki;Lee, Se-Han;Choi, Young-Kiu
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2004.11a
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    • pp.121-124
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    • 2004
  • In this paper, we address an active vibration control system, which suppresses the vibration engaged by magnetically levitated stage. The stage system consists of a levitating platen with four permanent magnetic linear synchronous motors in parallel. Each motor generates vertical force fer suspension against gravity and propulsion force horizontally as well. This stage can generate six degrees of freedom motion via the vertical and horizontal forces. In the stage system, which represents the settling-time critical system. the motion of the platen vibrates mechanically. We designed an active vibration control system for suppressing vibration due to the stage moving. The command feedforward with inertial feedback algorithm is used fer solving stage system's critical problems. The components of the active vibration control system are accelerometers for detecting stage table's vibrations, a digital controller with high precise signal converters, and electromagnetic actuators.

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Micro-positioning of a Smart Structure using an Enhanced Stick-slip Model (향상된 스틱-슬립 마찰 모델을 이용한 스마트 구조물의 마이크로 위치제어)

  • Lee, Chul-Hee;Jang, Min-Gyu;Choi, Seung-Bok
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2008.11a
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    • pp.230-236
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    • 2008
  • In this paper, a model-based stick-slip compensation for the micro-positioning is proposed using an enhanced stick-slip model based on statistical rough surface contact model. The smart structure is comprised with PZT (lead (Pb) zirconia (Zr) Titanate (Ti)) based stack actuator incorporating with the PID (Proportional-Integral-Derivative) control algorithm, mechanical displacement amplifier and positioning devices. For the stick-slip compensation, the elastic-plastic static friction model is used considering the elastic-plastic asperity contact in the rough surfaces statistically. Mathematical model of system for the positioning apparatus was derived from the dynamic behaviors of structural parts. PID feedback control algorithms with the developed stick-slip model as well as feedforward friction compensator are formulated for achieving the accurate positioning performance. Experimental results are provided to show the performances of friction control using the developed positioning apparatus.

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Sensorless Control of Induction Motors with Simultaneous Estimation of Speed and Rotor Resistance in the Very Low Speed Region (속도와 2차 저항의 동시 추정이 가능한 유도전동기의 극 저속 영역 센서리스 속도제어)

  • 정석권;이진국;유삼상
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.53 no.9
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    • pp.552-561
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    • 2004
  • This paper is concerned with a new speed sensorless induction motor scheme which can be successfully applied to at any speed including even zero speed. The proposed method is robust against rotor resistance variations. In addition, simultaneous on-line estimations of speed and rotor resistance are realized based on a feedforward type torque control approach. The rotor flux with a low frequency sinusoidal waveform has been utilized to help the simultaneous estimation for both speed and rotor resistance. The control scheme has no current minor loop to determine voltage references. Since the proposed estimation does not depend on any derivative terms of currents and stator voltages, it offers a good performance at extremely low speed region for sensorless induction motor. Furthermore, the proposed control is simply using motor parameters and stator currents without determining any PI gains for current feedback and any signal injection for the rotor resistance estimation. Finally, both simulation and experimental results are given to show the effectiveness of this method.

A Study on the Coagulant Dosing Control Based on Neural Network and Streaming Current Detector for Water Treatment Plant (신경망과 유동전류계를 이용한 정수장 응집제 주입제어에 관한 연구)

  • Kim, Ki-Pyung;Kim, Yong-Yeol;Yoo, Jun;Kang, Yi-Seok
    • Journal of Institute of Control, Robotics and Systems
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    • v.10 no.6
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    • pp.551-556
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    • 2004
  • Coagulation process is one of the most important processes in water treatment procedures for stable and economical operation, and coagulant dosing of this process for most plants is generally determined by the jar test. However, this method does not only take a long time to analyze and get the result but also has difficulties in applying to automatic control. This paper shows the feasibility of applying neural network to control the coagulant dosing automatically in water treatment plant. To be specific, the predicted results of the neural network model is shown to be similar to that of jar test. The input variables for learning the neural network are turbidity, water temperature, pH, and alkalinity. Combining the neural network and SCD(Streaming Current Detector) for feedforward and feedback control of injecting coagulant, a rapid change of the raw water quality can be accommodated.

Micro-positioning of a Smart Structure Using an Enhanced Stick-slip Model (향상된 스틱-슬립 마찰 모델을 이용한 스마트 구조물의 마이크로 위치제어)

  • Lee, Chul-Hee;Jang, Min-Gyu;Choi, Seung-Bok
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.18 no.11
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    • pp.1134-1142
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    • 2008
  • In this paper, a model-based stick-slip compensation for the micro-positioning is proposed using an enhanced stick-slip model based on statistical rough surface contact model. The smart structure is comprised with PZT(lead (Pb) zirconia(Zr) Titanate(Ti)) based stack actuator incorporating with the PID(proportional-integral-derivative) control algorithm, mechanical displacement amplifier and positioning devices. For the stick-slip compensation, the elastic-plastic static friction model is used considering the elastic-plastic asperity contact in the rough surfaces statistically. Mathematical model of system for the positioning apparatus was derived from the dynamic behaviors of structural parts. PID feedback control algorithms with the developed stick-slip model as well as feedforward friction compensator are formulated for achieving the accurate positioning performance. Experimental results are provided to show the performances of friction control using the developed positioning apparatus.

Nonlinear Model-Based Robust Control of a Nuclear Reactor Using Adaptive PIF Gains and Variable Structure Controller (적응 PIF Gain 및 가변구조 제어기를 사용한 비선형 모델에 의한 원자로의 Robust Control)

  • Park, Moon-Ghu;Cho, Nam-Zin
    • Nuclear Engineering and Technology
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    • v.25 no.1
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    • pp.110-124
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    • 1993
  • A Nonlinear model-based Hybrid Controller (NHC) is developed which consists of the adaptive proportional-integral-feedforward (PIF) gains and variable structure controller. The controller has the robustness against modeling uncertainty and is applied to the trajectory tracking control of single-input, single-output nonlinear systems. The essence of the scheme is to divide the control into four different terms. Namely, the adaptive P-I-F gains and variable structure controller are used to accomplish the specific control actions by each terms. The robustness of the controller is guaranteed by the feedback of estimated uncertainty and the performance specification given by the adaptation of PIF gains using the second method of Lyapunov. The variable structure controller is incorporated to regulate the initial peak of the tracking error during the parameter adaptation is not settled yet. The newly developed NHC method is applied to the power tracking control of a nuclear reactor and the simulation results show great improvement in tracking performance compared with the conventional model-based control methods.

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Sensorless Force Control with Observer for Multi-functional Upper Limb Rehabilitation Robot (다기능 재활운동을 위한 힘 센서가 없는 상지 재활 로봇의 힘 제어)

  • Choi, Jung Hyun;Oh, Sehoon;An, Jinung
    • The Journal of Korea Robotics Society
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    • v.12 no.3
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    • pp.356-364
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    • 2017
  • This paper presents a force control based on the observer without taking any force or torque measurement from the robot which allows realizing more stable and robust human robot interaction for the developed multi-functional upper limb rehabilitation robot. The robot has four functional training modes which can be classified by the human robot interaction types: passive, active, assistive, and resistive mode. The proposed observer consists of internal disturbance observer and external force observer for distinctive performance evaluation. Since four training modes can be quantitatively identified as impedance variation, position-based impedance control with feedback and feedforward controller was applied to the assistive training mode. The results showed that the proposed sensorless observer estimated cleaner and more accurate force compared to the force sensor and the impedance controller embedded with the proposed observer completed the assistive training mode safely and properly.

Development of Joint Controller and Collision Detection Methods for Series Elastic Manipulator of Relief Robot (구호로봇용 연성 매니퓰레이터를 위한 조인트 제어 및 충돌감지 알고리즘)

  • Jung, Byung-jin;Kim, Tae-Keun;Won, Geon;Kim, Dong Sup;Hwang, Junghun
    • The Journal of Korea Robotics Society
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    • v.13 no.3
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    • pp.157-163
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    • 2018
  • This paper deals with the development and application of control algorithms for series elastic relief robots for rescue operations in harsh environment like disasters or battlefield. The joint controller applied in this paper has a cascade structure combining inner loop for torque control and outer loop for position control. The torque loop contains feedforward and feedback controller and disturbance observer for independent, decentralized joint control. The effect of the elastic component and motor dynamics are treated as the nonlinear disturbance and compensated with the disturbance observer of torque controller. For the collision detection, Band Designed Disturbance Observer is configured to recognize/respond to external disturbance robustly in the continuously changing environment. The controller is applied to a 7-dof series elastic manipulator to evaluate the torque tracking and collision detection/response performance.

A Study on Source Current Control of Voltage Source PWM Converter based on Lossless Resonator (무손실 공진기를 가지는 전압형 PWM 컨버터의 전원전류 제어에 관한 연구)

  • Heo, T.W.;Shin, D.W.;Kim, G.H.;Jin, H.J.;Woo, J.I.
    • Proceedings of the KIEE Conference
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    • 1997.07f
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    • pp.2040-2042
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    • 1997
  • A voltage source PWM converter based on lossless resonator and a source current control system are proposed in this paper. It is proved that steady-state deviation reduces to zero from the transfer function of source current control system, owing to the lossless resonator. The system can be controlled by the feedback control only, because of no need to use a feedforward control in the proposed a source current control system. Therefore, as using lossless resonator, control system can be simply made up. Simulations are described in the case of difference between source current and source current reference.

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Simple AI Robust Digital Position Control of PMSM using Neural Network Compensator (신경망 보상기를 이용한 PMSM의 간단한 지능형 강인 위치 제어)

  • 윤성구
    • Proceedings of the KIPE Conference
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    • 2000.07a
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    • pp.620-623
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    • 2000
  • A very simple control approach using neural network for the robust position control of a Permanent Magnet Synchronous Motor(PMSM) is presented The linear quadratic controller plus feedforward neural network is employed to obtain the robust PMSM system approximately linearized using field-orientation method for an AC servo. The neural network is trained in on-line phases and this neural network is composed by a fedforward recall and error back-propagation training. Since the total number of nodes are only eight this system can be easily realized by the general microprocessor. During the normal operation the input-output response is sampled and the weighting value is trained multi-times by error back-propagation method at each sample period to accommodate the possible variations in the parameters or load torque. And the state space analysis is performed to obtain the state feedback gains systematically. IN addition the robustness is also obtained without affecting overall system response. This method is realized by a floating-point Digital Singal Processor DS1102 Board (TMS320C31) The basic DSP software is used to write C program which is compiled by using ANSI-C style function prototypes.

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