• Title/Summary/Keyword: Friction Disturbance

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A Study on the Collision Detection for Smart Door by Disturbance Observer (외란관측기를 이용한 스마트도어의 충돌감지에 관한 연구)

  • Park, Min-Kyu;Sung, Kum-Gil;Lee, Byungsoo
    • Journal of the Korean Society of Mechanical Technology
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    • v.13 no.4
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    • pp.31-36
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    • 2011
  • Smart Door(SD) is a human friendly power-assisted door system for passenger car doors. It offers comfort and safety to passengers and drivers by supplying additional power. In this study, dynamic system model and the equation of motion derivation are derived. And we propose the disturbance observer based collision detection algorithm for safety when opening the door. A disturbance caused by collision has a fast response compared to a friction, uncertainties and so on. The main idea this study is to estimate a variation of disturbance for stably and effectively detecting a collision. In order to evaluate a performance of collision detection, an experiment set up is constructed. The experimental results validate the usefulness of the proposed collision detection algorithm.

A Study on the Adaptive Friction Compensator Design of a Hydraulic Proportional Position Control System (유압 비례 위치제어시스템의 적응 마찰력 보상기 설계에 관한 연구)

  • 이명호;박형배
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.12 no.6
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    • pp.77-83
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    • 2003
  • This paper deals with a position control problem of a hydraulic proportional position control system using a nonlinear friction compensation control. As nonlinear friction, stiction and coulomb friction forces are considered and modeled as deadzone and external disturbance respectively. In order to compensate this nonlinearities, we designed the controller which is the adaptive friction compensator using discrete time Model Reference Adaptive Control method in this paper. Digital Signal Processing board is employed for data acquisition and manipulation. The experimental results show that response is slow and steady-state error cannot be compensated properly without friction compensation but this compensator is effective to obtain fast response and good steady-state response.

High speed and accurate positioning control of robot manipulator by using disturbance observer (외란 관측기를 이용한 직접 구동형 로봇의 고속.고정도 제어)

  • 서일홍;엄광식;권기호
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10b
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    • pp.948-951
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    • 1996
  • High-speed/high-accuracy control of robot manipulator becomes more and more stringent because of the external disturbance and nonlinear characteristics. To meet this ends, lots of control strategies were proposed in the past such as the computed torque control, the nonlinear decoupled feedback control, and adaptive control. These control methods need computations of the inverse dynamics and require much computational effort. Recently, a disturbance observer with unmodeled robot dynamics and simple algorithms to motion control have been widely studied. This paper proposes a motor control strategy based on the disturbance observer which estimate the disturbance of each joint from input-output relationship of the actuator and eliminate the estimated disturbance including the torque due to modeling errors, coupling force, nonlinear friction, and so on. To apply the disturbance observer to closedloop system like velocity servo pack, the modified control structure was constructed and shown that it is equivalent to a disturbance observer in open-loop system. Finally, using the proposed approach, simulation and experiments were carried out for a two-degree-of-freedom SCARA type direct drive robot, and show some results to verify the effectiveness of the proposed algorithms.

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Development of the disturbance observer for micro-stepping X-Y stage (마이크로 스텝핑 평판 스테이지의 외란 예측기의 개발)

  • Kim Jung-Han
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.14 no.3
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    • pp.23-31
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    • 2005
  • The purpose of this study is to design a disturbance observer for a micro-stepping stage to eliminate the disturbances from cables, friction, mass unbalance of the moving part, etc. The disturbance observer is designed for air-floating X-Y precision micro-stepping X-Y stage which widely used in stepper machine or semiconductor manufacturing systems. The micro-stepping X-Y stage has a weak point of the variation of characteristics with position locations, which caused by various disturbances. In this study, it will be described that a simple and high throughput disturbance observer algorithm improves the dynamic error and settling time of the micro-stepping stage.

Periodic Adaptive Compensation of State-dependent Disturbance in a Digital Servo Motor System

  • Ahn, Hyo-Sung;Chen, YangQuan;Yu, Won-Pil
    • International Journal of Control, Automation, and Systems
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    • v.5 no.3
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    • pp.343-348
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    • 2007
  • This paper presents an adaptive controller for the compensation of state-dependent disturbance with unknown amplitude in a digital servo motor system. The state-dependent disturbance is caused by friction and eccentricity between the wheel axis and the motor driver of a mobile robot servo system. The proposed control scheme guarantees an asymptotical stability for both the velocity and position regulation. An experimental result shows the effectiveness of the adaptive disturbance compensator for wheeled-mobile robot in a low velocity diffusion tracking. A comparative experimental study with a simple PI controller is presented.

Impedance Control of Backdrivable Hydraulic Actuation Systems with Explicit Disturbance Estimation (직접 외란 추정을 통한 역구동성 유압 구동 시스템의 임피던스 제어)

  • Yoo, Sunkyum;Chung, Wan Kyun
    • The Journal of Korea Robotics Society
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    • v.14 no.4
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    • pp.348-356
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    • 2019
  • The backdrivable servovalve is a desirable component for force and interaction control of hydraulic actuation systems because it provides direct force generation mechanical impedance reduction by its own inherent backdrivability. However, high parametric uncertainty and friction effects inside the hydraulic actuation system significantly degrade its advantage. To solve this problem, this letter presents a disturbance-adaptive robust internal-loop compensator (DA-RIC) to generate ideal interactive control performance from the backdrivable-servovalve-based system. The proposed control combines a robust internal-loop compensator structure (RIC) with an explicit disturbance estimator designed for asymptotic disturbance tracking, such that the controlled system provide stable and ideal dynamic behavior for impedance control, while completely compensating the disturbance effects. With the aid of a backdrivable servovalve, we show that the proposed control structure can be implemented based on a simplified nominal model, and the controller enables implementation without accurate knowledge of the target system parameters and disturbances. The performance and properties of the proposed controller are verified by simulation and experiments.

Position Control of Sliding Mode Control Systems with Compensation of Estimated Coulomb friction (추정된 쿨롱 마찰을 보상한 슬라이딩 모드 제어 시스템의 위치제어)

  • 김한메;최정주;이영진;김종식
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.2
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    • pp.35-42
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    • 2004
  • The control systems with friction cause the steady state error and slow response, because friction is a sensitive to the change of system condition and has highly nonlinear characteristics. To overcome these problems and do precise position control for a ball-screw system, we use Coulomb friction estimator and the sliding mode control(SMC) to compensate its negative effect. The applied SMC for tracking position has a characteristics of robust stability and reducing chattering, and is derived from the Lyapunov stability theorem and reaching condition. Compensating the estimated friction torque to the bounded disturbance term of the SMC's equivalent control input, it has a tracking performance better than the PID from the experimental results.

Impulse Response Analysis of an Amplitude Proportional Friction Damper System (변위비례식 마찰댐퍼 시스템의 임펄스 가진 응답해석)

  • 최명진;박동훈
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.14 no.5
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    • pp.377-384
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    • 2004
  • An Amplitude Proportional Friction Damper (APFD), in which the friction force is proportional to the system displacement, has been introduced and mathematically modeled. To understand the damping characteristics of APFD, analytical solutions for the impulse response has been derivedand compared to the viscous damper. It is found that APFD system has very similar damping characteristics to viscous damper even though it is a friction damper. APFD may be used as a cost-effective substitution for the viscous damper and could also be used to improve the simple friction or Coulomb dampersince APFD works with no stick-slip and always returns to original position when external disturbance is disappeared.

Adaptive High Precision Control of Dynamic System Using Friction Compensation Schemes (마찰력 보상 기법을 이용한 동적 시스템의 고 정밀 적응제어)

  • Jeon, Buyng-Gyoon;Jeon, Gi-Joon
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.49 no.10
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    • pp.555-562
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    • 2000
  • We propose an adaptive nonlinear control algorithm for compensation of the stick-slip friction in a dynamic system. The friction force and mass of the system are estimated and compensated by adaptive control law. Especially, as the nonlinear control input in a small tracking error zone is enlarged by the nonlinear function, the steady state error is significantly reduced. The proposed algorithm is a direct adaptive control method based on the Laypunov stability theory, and its convergence is guaranteed under the bounded noise or torque disturbance. We verified the performance of the proposed algorithm by computer simulation on one-DOF mechanical system with friction.

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Precision Stabilization Control of Servo-system by Using Friction Compensation (마찰보상을 통한 서어보제어계의 정밀 안정화 제어)

  • Kang, Min-Sig
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.3 s.96
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    • pp.109-115
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    • 1999
  • This paper presents a stabilization control designed to improve position stabilization performance of a position servo-system(turret) mounted on a manuvering platform(vehicle). In the consideration of the motion of the platform, a dynamic model of the stabilization system is derived and shows the viscous and stick-slip friction torques are the major source of stabilization errors. An extended generalized minimum variance control which consists of a feedforward disturbance compensation as well as a pole placement feedback control is suggested to reduce the stabilization errors caused from the friction disturbances. This modeling and control are applied to a small experimental set-up and the experimental results confirm the accuracy of the model and the effectiveness of the suggested control.

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