• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.3
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• pp.643-650
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• 2017

The control of flexible joint robot is getting more attentions because its applications are more frequently used for robot systems in these days. This paper proposes a robust impedance controller for the flexible joint robot by using integral sliding mode control and backstepping control. The sliding mode control decouple disturbances completely but requires matching condition for disturbances. The dynamic model of flexible joint robot is divided into motor side and link side and the disturbance of the link side does not satisfy matching condition and cannot be decoupled directly by the actual input in the motor side. To overcome this difficulty, backstepping control technique is used with sliding mode control. The mismatched disturbance in the link side is changed into matched one in the respect to virtual control input which is the state controlled by actual input in the motor side. Integral sliding mode control is used to preserve the impedance control performance and the improved robustness at the same time.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.40 no.5
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• pp.299-307
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• 2003

The local structure of CMAC neural networks (NN) results in better and faster controllers for nonlinear dynamical systems. In this paper, we propose a CMAC NN-based disturbance observer and its corresponding controller for a flexible joint robot. The CMAC NN-based disturbance observer compensates for the parametric uncertainties and the external disturbances throughout the entire mechanical system. Finally, a simulation result is given to demonstrate the effectiveness of proposed design method's robust tracking performance.

• The Journal of the Korea institute of electronic communication sciences
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• v.4 no.3
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• pp.236-242
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• 2009

When two-link flexible arm is rotated about an joint axis, transverse vibration may occur. In this paper, vibration dynamics of flexible robot arm is modeled by using Bernoulli-Euler beam theory and Lagrange equation. Using the fact that matrix $\dot{D}$-2C is skew symmetric, new controllers which have a simplified structure with less computational burden is proposed. Lyapunov stability theory is applied to achieve a stable deterministic nonlinear controller for the regulation of joint angle.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.41 no.4
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• pp.1-12
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• 2004

This paper presents an adaptive fuzzy backstepping (AFB) controller for a single-link flexible joint robot in the Presence of Parametric uncertainties and external disturbances. Adaptive fuzzy logic systems are used as universal approximators to counteract the model uncertainties coming from robot dynamics and to compensate for the nonlinearities coming from adaptive backstepping method. The approach suggested herein does not require neither an additional supervisory nor a robustifying controller and guarantees that tracking error is uniformly ultimately bounded (UUB) within a sufficiently small residual set. Finally, a simulation result is given to demonstrate the robust tracking performance of proposed design method.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1831_1832
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• 2009

본 논문에서는 유연관절 로봇 팔 제어를 위한 토크센서 기반의 외란에 강인한 제어기 설계를 다루고 있다. 로봇은 관절의 토크센서를 통해 관절에서 발생하는 토크의 측정이 가능하며 외란에 강인한 제어기 설계를 위해 외란 관측기가 적용 되었다. 외란관측기는 시스템에 작용하고 있는 외란을 상쇄하는 역할을 한다. 본 논문에서 설계된 제어기의 성능은 컴퓨터 모의실험을 통하여 확인하도록 한다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1994.04a
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• pp.45-50
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• 1994

최근의 로봇 매니퓰레이터는 고정밀, 고생산성, 유연성 자동화를 추구한다. 이에 따라 매니퓰레이터는 운동 정확성, 고속성, 안정성이 더욱 향상되어야 한다. 특히 매니퓰레이터 관절부의 탄성은 동적 변형 및 진동을 유발함으로써 운동 정확성과 안정성을 현저히 저하시킨다. 이러한 복잡하고 불확실한 구조를 갖는 로봇 시스템의 고속, 정확한 운동 제어를 위해서는 보다 효과적인 고급 제어 기법 및 제어 장치의 개발이 요구된다. 본 연구에서는 이러한 문제에 대한 하나의 대응 방법으로 인간의 지식 처리 방법을 모방한 퍼지제어를 적용하여 그 가능성을 본다.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.5
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• pp.117-125
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• 1995

An improved robust control law is proposed for uncertain rigid robots. The uncertainty is nonlinear and (possibly fast) time-varying. Therefore, the uncertain factors such as imperfect modeling, friction, payload change, and external disturbances are all addressed. Based on the possible bound of the uncertainty, the controller is constructed. For uncertain flexible-joint robots, some feedback control terms are then added to the proposed robust control law in order to stabilize the elastic vibrations at the joints. To show that the proposed control laws are indeed applicable, the stability study based on Lyapunov function, a singular perturbation approach, and simulation results are presented.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.5
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• pp.1139-1144
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• 2012

The ration of payload to weight of industrial robot amounts form 1:10 to 1:30. Compared with man who have a ration of 3:1, it is very low. One of the goals for the next generation of robots will be a ration. This might be possible only by developing lightweight robots. When two-link flexible arm is rotated about an joint axis, transverse vibration may occur. In this paper, vibration dynamics of flexible arm is modeled by using Bernoulli-Euler beam theory and Lagrange equation. Using the fact that matrix $\dot{D}-2C$ is skew symmetric, new controllers which have a simplified structure with less computational burden is proposed by using Lyapunov stability theory. We propose deterministic and adaptive control laws for two link flexible arm, and the validity of the proposed control scheme is shown in computer simulation for two-link flexible arm.

• Journal of the Korean Institute of Intelligent Systems
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• v.23 no.1
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• pp.46-50
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• 2013

This paper proposes an adaptive fault accommodation control approach for flexible-joint (FJ) robots with multiple actuator faults. It is assumed that the value and occurrence time of multiple actuator faults are unknown. An adaptive fault accommodation control scheme with prescribed performance bounds, which characterize the convergence rate and maximum overshoot of tracking errors, is designed to accommodate the actuator faults. From the Lyapunov stability theorem, it is proved that all signals of the closed-loop system are semi-globally uniformly ultimately bounded and tracking errors are preserved within prescribed performance bounds regardless of actuator faults.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.6
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• pp.1203-1211
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• 2017

This paper proposes a robust controller for flexible joint robots to achieve tracking performance and to improve robustness against both matched and mismatched disturbances. The proposed controller consists of a disturbance observer(DOB), passivity-based controller, and integral sliding mode controller(ISMC) in a backstepping manner. The DOB compensates the mismatched disturbance in the link-side and formulates the reference input for the motor-side controller. Interconnection and damping assignment passivity-based controller (IDA-PBC) performs tracking control of motor-side, and it is integrated to nominal control of ISMC to guarantee the over-all stability of the nominal system, while, matched disturbances are decoupled by the discontinuous control of ISMC. In the design of the link-side controller, PD type impedance controller is designed with DOB and this leads the continuous control input which is suitable to the reference input for the motor-side.