• Journal of Mechanical Science and Technology
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• 제19권spc1호
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• pp.357-363
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• 2005

The non-minimum phase characteristic of a flexible manipulator makes tracking control of its tip difficult. The level of the tip tracking performance of a flexible manipulator is significantly affected by the characteristics of the tip reference trajectory as well as the characteristics of the flexible manipulator system. This paper addresses the question of how to best specify a reference trajectory for the tip of a flexible manipulator to follow in order to achieve the objectives of reducing : tip tracking error, residual tip vibration, and the required actuation effort at the manipulator joint. A novel method of tip-based learning controller for the flexible manipulator system is proposed in the paper, where a model of the flexible manipulator system with a command shaping filter is used to generate a smooth and realizable tip reference trajectory for a tip-based learning controller.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.404-408
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• 2005

Having flexibility in a manipulator will degrade trajectory tracking control and manipulator tip positioning. In practice, however, constraints imposed by various operating requirements, will render the presence of such flexibility unavoidable. The dynamic analysis of the flexible manipulator is essential in designing proper control systems. A flexible manipulator consists of infinite number of elastic modes and the modes are usually coupled to each other. For the practicality, however, it is usually assumed that the flexible system consists of finite number of elastic modes and the modes are decoupled. These assumptions result in a linear and decoupled mathematical model of the flexible manipulator and simplify the analysis of the dynamic behavior and the design of the control system. The decoupling and linearization of the flexible link, however, has been assumed without in depth analysis. This paper focuses on the analysis of the significance of the non-linear coupling factors.

• 한국소음진동공학회논문집
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• 제15권2호
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• pp.169-175
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• 2005

In this paper, a novel vibration control scheme for a single-link flexible manipulator system without using a vibration feedback sensor is proposed. In order to achieve the vibration information of the flexible link, a reaction moment estimator based on the dynamic characteristics of the flexible manipulator is proposed. While the manipulator is maneuvering the reaction moment is reciprocally acting on the flexible link and the hub inertia due to the vibration of the link. A sliding mode controller based on the equivalent rigid body dynamics corresponding to the proposed flexible manipulator is then augmented with the reaction moment estimator to realize a decentralized control system. The reaction moment estimator is implemented via the first order low pass filter. The performance of the proposed control scheme is verified by computer simulation and experiment.

• Advances in robotics research
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• 제1권1호
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• pp.61-79
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• 2014

This paper presents theoretical and experimental investigations into the dynamic modelling and characterisation of a two-link flexible manipulator incorporating payload. A planar two-link flexible manipulator that moves in a horizontal plane is considered. A dynamic model of the system is developed using a combined Euler-Lagrange and assumed mode methods, and simulated using Matlab. Experiments are performed on a lab-scaled two-link flexible manipulator for validation of the dynamic model and characterisation of the system. Two system responses namely hub angular position and deflection responses at both links are obtained and analysed in time and frequency domains. The effects of payload on the dynamic characteristics of the flexible manipulator are also studied and discussed. The results show that a close agreement between simulation and experiments is achieved demonstrating an acceptable accuracy of the developed model.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1808-1811
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• 1997

A position control algorithm for a flexible manipulato is stuudied. The proposed algorithm is based on a fuzzy theroy with a Steady State Genetic Algorithm(SSGA). The conventional fuzzy methods need expert's knowledges or human experiences. The SSGA, which is one of the optimization algorithms, tunes automatically the input-output membership parameters and fuzzy rules. The computer simulation is presented ot illustrate the approaches. Finally we applied a fuzzy theory with a SSGA to aposition control of a flexible manipulator.

• 한국지능시스템학회논문지
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• 제12권1호
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• pp.61-66
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• 2002

본 논문에서는 Flexible Manipulator의 제어를 위해 퍼지제어의 제약인 멤버쉽 함수, 퍼지규clr을 유전알고리즘으로 조정, 최적화 하는 새로운 제어기를 설계하였다. 사용된 유전알고리즘은 Steady State Genetic 알고리즘과 Adaptive 유전 알고리즘의 합성이다. 제안한 제어기는 Flexible Manipulator의 끝점 무게 0.8kmg, 최대속도 1m/s의 경우, 퍼지제어에 비해 오차가 90.8% 감소하고 신경회로망을 이용한 퍼지제어에 비하여는 31.8% 감소하였으며 진화전략과 퍼지제어합성에 의한 제어기보다는 오차가 31.3% 감소하는 통 제어성능과 그 유용성이 우수함을 확인하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1700-1703
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• 1997

The flexibility of the manipulator inevitably inducess the vibration at the end effector. For the increase in speed and accuracy at the end tip, in this work, position and vibration control of a flexible manipuator with a separate voice coil type actrator for vibration suppression, is studied. The flexible manipulator with a tip mass is modeled an Euler-Bernoulli beam. An H.inf. controller is designed in order to make the controlled system robust against unmodeled higher-order mode vibration of the manipulator, output sensor noise, and etc. Simulations and experiments show that the modeling of the system is valid and that robust vibration control of the flexible manipulator is efficiently achieved.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.599-606
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• 1992

A manipulator system that needs significantly large workspace volume and high payload capacity has greater link flexibility than typical industrial robots and teleoperators. If link flexibility is significant, position control of the manipulator's end-effector exhibits the nonminimum phase, noncollocated, and flexible structure system control problems. This paper addresses inverse dynamic trajectory planning issues of a flexible manipulator. The inverse dynamic equation of a flexible manipulator was solved in the time domain. By dividing the inverse system equation into the causal part and the anticausal part, the inverse dynamic method calculates the feedforward torque and the trajectories of all state variables that do not excite structural vibrations for a given end-point trajectory. Through simulation and experiment with a single-Unk flexible manipulator, the effectiveness of the inverse dynamic method has been demonstrated.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1269-1272
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• 1996

Several input shaping techniques are suggested to reduce the vibration of a flexible manipulator. The theories of typical 4 methods(Singer, Tuttle, Feddema, Zuo) are explained and are tested by the experiment of one link flexible manipulator. Zuo's method is the best of all with respect to its robustness.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.7-11
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• 1991

The adaptive control of flexible joint manipulator is the focus of this paper. The full order flexible joint manipulator dynamic system does not allow the determination of a feedback linearization control as for rigid manipulators. This drawback is overcome by a model order reduction based on a singular perturbation strategy. The full order flexible joint manipulator dynamic model is adopted for derivation of the adaptive control law to damp out the elastic oscillations at the joints. It is shown that the joint position error will converge to zero asymptotically and that other signals remain bounded without precise knowledge of parameters of the manipulator and its joint flexibility.