• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.229-232
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• 1996

The position control accuracy of the robot arm is decreased significantly when a long arm robot is operated at high speed. In this case, the robot arm must be modeled as a flexible structure, not a rigid one, and its control system will be necessarily designed with its elastic modes taken into account. In this paper, the vibration control of a one-link flexible robot arm is presented. The robot system consists of a flexible arm manufactured with thin aluminium plate, AC servomotor with a harmonic drive for speed reduction, optical encoder and accelerometer. The system is modeled with limited number of elastic modes, and its parameters are determined from the results of the experiments. The implemented control schemes are LQ control and sliding mode control. The experiments and digital simulations are carried out to test the validity of the system modeling, controller design, and active control implementation.

• 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.

• 대한기계학회논문집
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• 제17권2호
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• pp.385-392
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• 1993

This paper presents a new stable composite control law for the flexible joint robot manipulators, which incorporate an additional stabilizing control law with the sliding property. The singularly perturbated models in this paper include inertia moments which are functions or the deformations of actuators as well as link positions. The values of renewedly defined fast controller variables are computer from the corrected reduced-order model without additional computational loads. Proposed schemes are compared with the conventional one. The simulations for 2 DOF flexible joint manipulator show that the proposed schemes are more stable than the conventional scheme, and especially effective for the manipulator with high joint-flexibilities.

• 소음진동
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• 제6권2호
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• pp.187-196
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• 1996

A new control strategy to actively control the vibration of a very flexible single link manipulator is proposed and experimentally realized. The control scheme consists of two actuators; a motor mounted at the beam hub and a piezoceramic bonded to the surface of the flexible link. The control torque of the motor to produce a desired angular motion is firstly determined by employing a sliding mode control theory on the equivalent rigid dynamics. The torque is then applied to the flexible manipulator in order to activate the commanded motion. During the motion, underirable oscillation is actively suppressed by applying a feedback control voltage to the piezoceramic actuator. Consequently, the desired tip position is favorably accomplished without vibration. Measured control responses are presented in order to demonstrate the efficiency of the proposed control methodology.

• 융합신호처리학회논문지
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• 제3권2호
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• pp.76-82
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• 2002

본 연구는 유연한 로봇팔의 선단 위치를 제어하기 위한 강인한 제어기의 설계하고 이것의 효과를 실험을 통하여 확인하는 데 있다. 이를 위해 먼저 유연한 로봇팔의 모델링을 Lagrange 방정식을 이용하여 수행하여 시스템의 수식모델을 구한 뒤, 이 모델을 기본으로 하는 강인한 제어기의 설계를 LMI(Linear Matrix Inequality)을 적용한 H$_{\infty}$이론을 도입하여 수행한다. 이 과정에서 로봇팔의 선단부하 변경으로 인한 시스템 파라미터의 변동을 플랜트가 가지는 불확실성 영역으로 간주하여 이를 설계에 적극적으로 반영함으로서 결과적으로 플랜트의 파라미터 변동에 강인한 제어기를 구현하고 이것의 유효성을 실험을 통하여 확인한다. .실험을 통하여 확인한다. .

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국제학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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• pp.987-992
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• 1988

In recent years there has been much interest in using light-weight, higher performance arms for both commercial and space-based applications, leading to the research of flexible robot manipulator. This paper is concerned with the trajectory control of a flexible arm using inverse dynamics. Inverse problems are important to robot control and programming, since they allow one to find the appropriate inputs necessary for producing the desired outputs. The input is obtained by the numerical inversion of Laplace transformation in the time domain. And we attempt the trajectory control experiment of a flexible arm using this calculated input. In this article we compare the numerical results with experimental results and can find good agreement. The results make clear that this technique has the good potential for the control of tip trajectory of flexible robot arms.

• 동력기계공학회지
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• 제5권2호
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• pp.79-86
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• 2001

A method is presented for generating the path which significantly reduces residual vibration of the redundant, flexible robot manipulator in the presence of obstacles. The desired path is optimally designed so that the system completes the required move with minimum residual vibration, avoiding obstacles. The dynamic model and optimal path are effectively formulated and computed by using special moving coordinate, called VLCS, to represent the link flexibility. The path to be designed is developed by a combined Fourier series and polynomial function to satisfy both the convergence and boundary condition matching problems. The concept of correlation coefficients is used to select the minimum number of design variables. A planar three-link manipualtor is used to evaluate this method. Results show that residual vibration can be drastically reduced by selecting an appropriate path, in the presence of obstacles.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.552-555
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• 1997

Recently, increasing attention has been paid to the application of learning control method to robot manipulator control. Because the learning control method does not require an exact dynamic model, it is flexible and easy to implement. In this paper, we implement a learning control scheme which consists of a unique feedforward learning controller and a linear feedback controller. The learning control method does not require acceleration terms that are sensitive to noise and has the capability of rejecting unknown disturbances and adapting itself to time-varying system parameters. The feasibility of the learning control scheme is soon by implementing the control scheme to a commercial robot manipulator and the performance of which is also compared with the conventional linear PID control method.

• 대한전기학회논문지
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• 제45권1호
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• pp.123-130
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• 1996

Due to high payload capacity and high length-to -cross-section ratio requirements, long-reach manipulator systems are expected to exhibit significant structural flexibility. To avoid structural vibrations during operations, various types of input shaping filtering methods have been investigated. A robust notch filtering method and an impulse shaping filtering method were investigated and implemented. In addition, two very different approaches have been developed and compared. One new approach, referred to as a

• International Journal of Control, Automation, and Systems
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• 제6권5호
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• pp.677-688
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• 2008

In this paper, the general problem of impedance control for a robotic manipulator with a moving flexible base is addressed. Impedance control imposes a relation between force and displacement at the contact point with the environment. The concept of impedance control of flexible base mobile manipulator is rather new and is being considered for first time using singular perturbation and new sliding mode control methods by authors. Initially slow and fast dynamics of robot are decoupled using singular perturbation method. Slow dynamics represents the dynamics of the manipulator with rigid base. Fast dynamics is the equivalent effect of the flexibility in the base. Then, using sliding mode control method, an impedance control law is derived for the slow dynamics. The asymptotic stability of the overall system is guaranteed using a combined control law comprising the impedance control law and a feedback control law for the fast dynamics. As first time, base flexibility was analyzed accurately in this paper for flexible base moving manipulator (FBMM). General dynamic decoupling, whole system stability guarantee and new composed robust control method were proposed. This proposed Sliding Mode Impedance Control Method (SMIC) was simulated for two FBMM models. First model is a simple FBMM composed of a 2 DOFs planar manipulator and a single DOF moving base with flexibility in between. Second FBMM model is a complete advanced 10 DOF FBMM composed of a 4 DOF manipulator and a 6 DOF moving base with flexibility. This controller provides desired position/force control accurately with satisfactory damped vibrations especially at the point of contact. This is the first time that SMIC was addressed for FBMM.