• 대한기계학회논문집A
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• 제20권12호
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• pp.3883-3891
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• 1996

Performance and productivity of robot manipulator can be improved by increasing its working speed and extending its link length. But heavy weght of the commercial robot links, considered as "rigid body", limits its mazimum working speed and the weght of the links can be reduced for high speed operation. But this light-weight link or long link for special use cannot be consideredas "rigid" structure and vibration of the link due to its flexibility causes errors in end-effector position and orientation. Thus the elastic behaviro of the flexible link should be taken care of for increasing work speed and getting smaller error of end-effector position. In this paper, the fuzzy control theory is selected to design the controller which controlos the joint positions of the robot manipulator and suppress the vibration of flexible link. In the forst place, for the 1 DOF flexible link system, the fuzzy control theory is implemented. The contdroller for the 1 DOF flexible link system is designed. Experimental research is carried out to examine the controllability and the validity of the fuzzy control theory based controller. Next, using the extended desing schemes for the case of the 1 DOF flexible link system and usign the experimental phenomena of the 3 DOF flexible link system, the fuzzy controller for the 3 DOF flexible link system is desinged and experimented.ed and experimented.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.511-516
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• 2000

In order to not only perform as a extreme model under the severe operating condition but also acquire more diverse and advanced control capability utilizing high compliance, active vibration control of a flexible 2-link robot manipulator are investigated. Multi variable-structured frequency shaped optimal sliding mode is proposed for the flexible robot manipulator like control system, whose control variables, an angular motion of joint and vibration of flexible link, have to be controlled simultaneously by one control torque at a driving joint. The control system is divided into two subsystems, a control input related subsystem and an added subsystem. The proposed sliding mode, composed of multi control variables, makes optimized relation between subsystems and a individual control input, thus, the sliding mode controller can compensate whole dynamics of each subsystems simultaneously. And the possibility and effectiveness are verified by vibration control of a manipulator having two flexible links. Simulation and experiment results show that the proposed control scheme achieves the purpose effectively.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.357-358
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• 2013

• 로봇학회논문지
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• 제9권1호
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• pp.11-19
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• 2014

In this paper, an external torque estimation problem in one-degree-of-freedom (1-DOF) flexible-joint robot equipped with a joint-torque sensor is revisited. Since a sensor torque from the joint-torque sensor is distorted by two dynamics having a spring connection, i.e., motor dynamics and link dynamics of a flexible-joint robot, a model-based estimation, rather than a simple linear spring model, should be required to extract external torques accurately. In this paper, an external torque estimation algorithm for a 1-DOF flexible-joint robot is proposed. This algorithm estimates both an actuating motor torque from the motor dynamics and an external link torque from the link dynamics simultaneously by utilizing the flexible-joint robot model and the Kalman filter estimation based on random-walk model. The basic structure of the proposed algorithm is explained, and the performance is investigated through a custom-designed experimental testbed for a vertical situation under gravity.

• 한국정밀공학회지
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• 제25권6호
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• pp.62-70
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• 2008

An adaptive fuzzy backstepping controller is proposed for the motion control for a single-link flexible-joint robot in the presence of parametric uncertainties. Fuzzy logic system is used to approximate the uncertainties of functions and a backstepping technique is employed to deal with the mismatched problem. A compensation controller is also employed to estimates the bound of approximation error so that the shattering effect of the control effort can be reduced. Thus the asymptotic stability of the closed loop control system can be obtained based on a Lyapunov synthesis approach. Numerical simulation results for a single-link flexible-joint robot are included to show the effectiveness of proposed controller.

• 소음진동
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• 제5권3호
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• pp.385-394
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• 1995

Recently, since robot manipulator becomes faster and lighter, its link is no longer regarded as rigid body, and robot controller which only controls robot position cannot reduce vibration of the flexible link. Therefore vibration control is needed in robot manipulator control in addition to position control. In the case that tip mass changes when robot manipulator in working, it is clear that the efficiency of the vibration/position controller designed for the fixed system goes down. In this paper, the system with time varying parameters, adaptive control theory is adopted which estimates parameters changed by the variation of the tip mass and re-calculates the gain of the controller. Validify of the proposed adaptive controller and capability of the estimator are evaluated by computer simulations and experiments. Comparison results of the optimal controller for the fixed system and proposed adaptive controller and carried out.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1704-1707
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• 1997

In this work, position and vibratiion control of a two-link manipulator with one flexible link, which an unkoun but bounded payload mass and two pair of artificial muscle-type penumatic actuators, are investgated. A flexible link robot has advantages over a figid link robot in the sense that it is much safer when it cones into contact with its environment, including humans. Furthermore, for the sake of safety, it would be more desirabel if an actuator could deliver required force while maintaining proper compliance. An artificial muscle-type penumatic actuator is adequate for such cases. In this study, a controller based on singular perturbation method, adaptive and sliding mode contro, and .mu.-synthesis is developed. The effectiveness of the proposed control scheme is confirmed through simulations and experiments.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.1036-1041
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• 1993

The tip of the flexible robot arm has to be controlled by the active control reducing vibration because it has residual vibration after getting to desired position. This paper presents an end-point position control of a 1-link flexible robot arm having tip mass by the PID control algorithm. The system is composed of a flexible arm with tip mass, dc servomotor and ballscrew mechanism under translational motion. The feedback signal composed of the tip displacement measured by laser sensor, estimated velocity and acceleration is used to control the base motion. Theoretical results are obtained by applying the Laplace transform and the numerical inversion method to the governing equations. After the flexible robot arm reaches to. the desired position, the residual vibration is controlled by the PID algorithm. This paper gives the simulation and experimental results of end-point responses according to changing tip-mass and arm length. And this algorithm shows good effects of reducing the residual vibration. Approximately, theoretical response is in good agreement with experimental one.

• 한국정밀공학회지
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• 제14권2호
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• pp.160-168
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• 1997

A $H_{\infty}$self-tuning control scheme for the tip position of a flexible link robot handling unknown loads is presented here. The scheme essentially comprises a recursive least-squares identification algorithm and $H_{\infty}$self-tunning controller. The $H_{\infty}$control low is designed to be robust to uncertain parameters and the self-tunning action provides adaption to unknown parameters. Through numerical study, the performance comparison of the $H_{\infty}$self-tuning controller with a constant gain $H_{\infty}$controller as well as a LQG self-tuning controller clearly shows its superior ability in handling load changes in quiescent states.nt states.

• 한국정보통신학회논문지
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• 제21권3호
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• pp.643-650
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• 2017

최근에 유연관절로봇의 제어는 로봇시스템에 있어서 다양한 적용가능성이 증가하고 있기 때문에 점점 그 중요성이 커지고 있다. 본 논문에서는 유연관절로봇의 제어에 있어서 적분슬라이딩모드제어기와 백스테핑제어기법을 도입하여 강인성을 증가시키는 방법을 제안한다. 슬라이딩모드제어기를 사용하여 강인성을 향상시키기 위해서는 제어대상이 정합조건을 만족시켜야 하는데 유연관절로봇은 이 조건을 만족시키지 못한다. 유연관절로봇은 링크측과 모터측으로 나누어 생각할 수 있고 각 측에 외란이 존재하나 실제입력은 모터측에 존재하기 때문에 링크측 외란은 정합조건을 만족시킬 수 없으므로 슬라이딩모드제어기로 제거하기가 어렵다. 이에 본 논문에서는 백스테핑을 도입하여 이러한 비정합 문제를 해결함으로써 링크측 외란의 영향을 제거할 수 있도록 한다. 이와 더불어 임피던스제어 성능을 가질 수 있도록 적분슬라이딩모드제어기를 함께 사용한다.