• Title, Summary, Keyword: Position Control

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Precise Position Synchronous Control of Four-Axes System Based on Acceleration Control (가속도제어에 의한 4축 시스템의 정밀 위치동기제어)

  • Jeong, Seok-Kwon;Choi, Bong-Seok;You, Sam-Sang
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.9
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    • pp.1245-1254
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    • 2004
  • In this paper, we deal with a precise position synchronous control of four-axes system which is working under various load disturbances. Each axis driving system is consisted of a speed controller and an acceleration controller as an inner loop instead of conventional current control scheme. The acceleration control plays an important roll to suppress load disturbances quickly. Also, each axis is coupled by a maximum position synchronous error comparison to minimize position synchronous errors according to integration of speed differency. As a result, the proposed system enables precise synchronous control with good robustness against load disturbances during transient as well as steady state. The stability and robustness of the proposed system are investigated through its frequency characteristic and numerical simulations. Finally, experimental results under load disturbances demonstrate the effectiveness of the proposed control system fur four-axes position synchronous control.

A Study on Current, Velocity, Position Gain Tuning Technique of Servo Position Controller using Simulation (시뮬레이션을 이용한 서보 위치제어기의 전류, 속도, 위치이득 동조기법에 관한 연구)

  • Park, Ki-Woo
    • Journal of Institute of Control, Robotics and Systems
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    • v.17 no.7
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    • pp.634-640
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    • 2011
  • When a servo position controller of a robot or a driving units is composed of a PID controller, servomechanism which is modelled is composed of current, velocity and position control loops. After this model is simulated, the technique operating gain of each controller is suggested. The model consists of current, velocity and position controllers from the inside to the outside gradually. Also, to combine velocity and position controllers with 2 order system, simulation is performed after current controllers are composed, which are able for current loop to work ideally. If a current controller is treated with constant, it is possible for velocity and position controller to consist of controller into 2 order system. The technique is verified by applying T-company servo motor which is much more applied to current, velocity and position controller robots.

Stepping motor controlling apparatus

  • Le, Ngoc Quy;Jeon, Jae-Wook
    • 제어로봇시스템학회:학술대회논문집
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    • pp.1858-1862
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    • 2005
  • Stepping motor normally operates without feedback and may loss the synchronization. This problem can be prevented by using positional feedback. This paper introduces one method for closed loop control of stepping motor and a method for combining full-step control and micro-step control. This combination controlling apparatus can perform position control with high accuracy in a high speed, so that it will not suffer from vibration (or hunting) problem when stopping motor. Controlling apparatus contains a position counter block for detecting rotor position of stepping motor, a driving block for supplying current to windings of stepping motor, a control block for comparing output signal of position counter block with command position (desired position) and outputting current command signal based on deviation between current position and command position of rotor. To output current command signal, the control block refers to a sine wave data table. This table contains value of duty cycle of Pulse Width Modulation signal. As the second object of this paper, the process of building this data table is also presented.

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High Response and Precision Control of Electronic Throttle Controller Module without Hall Position Sensor for Detecting Rotor Position of BLDCM

  • Lee, Sang-Hun;Ahn, Jin-Woo
    • Journal of international Conference on Electrical Machines and Systems
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    • v.2 no.1
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    • pp.97-103
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    • 2013
  • This paper describes the characteristics of Electronic Throttle Controller (ETC) module in BLDC motor without the hall sensor for detecting a rotor position. The proposed ETC control system, which is mainly consisted of a BLDC motor, a throttle plate, a return spring and reduction gear, has a position sensor with an analogue voltage output on the throttle valve instead of BLDC motor for detecting the rotor position. So the additional commutation information is necessarily needed to control the ETC module. For this, the estimation method is applied. In order to improve and obtain the high resolution for the position control, it is generally needed to change the gear ratio of the module or the electrical switching method etc. In this paper, the 3-phase switching between successive commutations is adapted instead of the 2-phase switching that is conventionally used. In addition, the position control with a variable PI gain is applied to improve a dynamic response during a transient period and reduce vibration at a stop in case of matching position reference. The mentioned method can be used to estimate the commutation state and operate the high-precision position control for the ETC module and the high response characteristics. The validity of the proposed method is examined through the experimental results.

Robust Hybrid Position/Force Control of a PUMA-Like Robot Manipulator (PUMA형 로보트 머니플레이터의 강인한 위치/힘 혼합제어)

  • Park, Jae-Wook;Lee, Gun-Bok
    • Proceedings of the KIEE Conference
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    • pp.575-578
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    • 1995
  • In general, the control of robot manipulator is classified into position control and force control. Position controllers give adequate performance when a manipulator is following a trajectory through space and end-effector has no contact with environment. However for most tasks performed by robot manipulator in industry, contact is made between the end-effector and manipulator's environment, so position control may not suffice. The objective of this study is to control both position of a manipulator and the contact forces generated at the hand by using a conceptually simple control law. Position and force control problem is decoupled into subtasts via taskspace formulation and inverse dynamics. Then, the position controllers are designed for the task space variable which represent tangent motion and the forte controllers are designed for the lash space variables which represent normal force.

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Sensorless Control of a PMSM at Low Speeds using High Frequency Voltage Injection

  • Yoon Seok-Chae;Kim Jang-Mok
    • Journal of Power Electronics
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    • v.5 no.1
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    • pp.11-19
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    • 2005
  • This paper describes the two control techniques to perform the sensorless vector control of a PMSM by injecting the high frequency voltage to the stator terminal. The first technique is the estimation algorithm of the initial rotor position. A PMSM possesses the saliency which produces the ellipse of the stator current when the high frequency voltage is injected into the motor terminal. The major axis angle of the current ellipse gives the rotor position information at a standstill. The second control technique is a sensorless control algorithm that injects the high frequency voltage to the stator terminal in order to estimate the rotor position and speed. The rotor position and speed for sensorless vector control is calculated by appropriate signal processing to extract the position information from the stator current at low speeds or standstill. The proposed sensorless algorithm using the double-band hysteresis controller exhibits excellent reference tracking and increased robustness. Experimental results are presented to verify the feasibility of the proposed control schemes. Speed, position estimation and vector control were carried out on the floating point processor TMS320VC33.

Hybrid PD-Servo State Feedback Control Algorithm for Swing up Inverted Pendulum System

  • Nundrakwang, Songmoung;Benjanarasuth, Taworn;Ngamwiwit, Jongkol;Komine, Noriyuki
    • 제어로봇시스템학회:학술대회논문집
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    • pp.690-693
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    • 2005
  • In this paper, a hybrid PD-servo state feedback control algorithm for swing up inverted pendulum system is proposed. It consists of two parts. The first part is the PD position control for swinging up the pendulum from the natural pendent position to around the upright position and the second part is the servo state feedback control for stabilizing the inverted pendulum in upright position. The first controller is PD controller and it is tuned to control the position of the pendulum by moving the cart back and forth until the pendulum swings up around the upright position. Then the second controller will be switched to stabilize the inverted pendulum in its upright position. The controller in this stage is the servo state feedback controller designed by pole placement. Experimental results of PD type swinging up control system, of stabilizing servo state feedback control system and of the proposed hybrid PD-servo state feedback control system to swing up and stabilize inverted pendulum show that the proposed method is effective and reliable for actual implementation while it is simple.

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Hybrid position/force control of uncertain robotic systems using neural networks (신경회로망을 이용한 불확실한 로봇 시스템의 하이브리드 위치/힘 제어)

  • Kim, Seong-U;Lee, Ju-Jang
    • Journal of Institute of Control, Robotics and Systems
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    • v.3 no.3
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    • pp.252-258
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    • 1997
  • This paper presents neural networks for hybrid position/force control which is a type of position and force control for robot manipulators. The performance of conventional hybrid position/force control is excellent in the case of the exactly-known dynamic model of the robot, but degrades seriously as the uncertainty of the model increases. Hence, the neural network control scheme is presented here to overcome such shortcoming. The introduced neural term is designed to learn the uncertainty of the robot, and to control the robot through uncertainty compensation. Further more, the learning rule of the neural network is derived and is shown to be effective in the sense that it requires neither desired output of the network nor error back propagation through the plant. The proposed scheme is verified through the simulation of hybrid position/force control of a 6-dof robot manipulator.

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Joint Position Control using ZMP-Based Gain Switching Algorithm for a Hydraulic Biped Humanoid Robot (유압식 이족 휴머노이드 로봇의 ZMP 기반 게인 스위칭 알고리즘을 이용한 관절 위치 제어)

  • Kim, Jung-Yup;Hodgins, Jessica K.
    • Journal of Institute of Control, Robotics and Systems
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    • v.15 no.10
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    • pp.1029-1038
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    • 2009
  • This paper proposes a gain switching algorithm for joint position control of a hydraulic humanoid robot. Accurate position control of the lower body is one of the basic requirements for robust balance and walking control. Joint position control is more difficult for hydraulic robots than it is for electric robots because of an absence of reduction gear and better back-drivability of hydraulic joints. Backdrivability causes external forces and torques to have a large effect on the position of the joints. External ground reaction forces therefore prevent a simple proportional-derivative (PD) controller from realizing accurate and fast joint position control. We propose a state feedback controller for joint position control of the lower body, define three modes of state feedback gains, and switch the gains according to the Zero Moment Point (ZMP) and linear interpolation. Dynamic equations of hydraulic actuators were experimentally derived and applied to a robot simulator. Finally, the performance of the algorithm is evaluated with dynamic simulations.

The Design, Fabrication, and Characteristic Experiment for Control Rod Position Indicator Using Reed Switch in System-Integrated Modular Advanced Reactor (리드스위치를 이용한 일체형원자로용 제어봉 위치지시기 설계 제작 및 특성해석)

  • Hur, Hyung;Kim, Jong-In;Kim, Kern-Jung
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.52 no.8
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    • pp.452-461
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    • 2003
  • The reliability and accuracy of the information on control rod position are very important to the reactor safety and the design of the core protection system. A survey on the RSPT(Reed Switch Position Transmitter) type control rod position indicator system and its actual implementation in the existing nuclear power plants in Korea was performed first. The control rod position indicator having the high performance for SMART was developed on the basis of RSPT technology identified through the survey. The arrangement of permanent magnet and reed switches is the most important procedure in the design of control rod position indicator. The hysteresis of reed switches is one of the important factors in a repeat accuracy of control rod position indicator as well. This paper investigates efficiency of the magnetic flux concentrator and the hysteresis using FEM and verified differences in physicals characteristics by comparing the results of FEM and those of the experiment. As a result, it is shown that the characteristics of prototype control rod position indicator have a good agreement with the results of FEM.