• Journal of the Korean Society for Precision Engineering
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• v.25 no.6
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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.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.1
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• pp.1-7
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• 2012

This paper introduces the mechanical design, fabrication, and control of a biomimetic fish robot whose driving motions resemble a real fish's flexibility and movement. This robot uses two motors create flexible movement like that of a fish. Several schemes, such as neutral buoyancy, fast underwater swimming, and direction changes, are introduced. The tail of the fish robot is made of a polymer material for flexible movement. The interior of the tail contains a joint and a wire. A sine wave command was applied to the tail to produce motion resembling a real fish swimming, and a buoy control device was installed. The up and down motion of the robot fish was controlled using this device.

• 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.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.260-265
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• 1992

This paper presents an adaptive control scheme for flexible joint robot manipulators. This control scheme is based on the Lyapunov direct method with the arm energy-based Lyapunov function. The proposed adaptive control scheme uses only the position and velocity feedback of link and motor shaft. The adaptive control system of flexible joint robots is asymptotically stable regardless of the joint flexibility value. Therefore, the assumption of weak joint ealsticity is not needed. Also, joint flexibility value is unknown. Simulation results are presented to show the feasibility of the proposed adaptive control scheme.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.261-262
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• 2012

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.648-653
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• 1993

This paper presents an nonlinear observer scheme for flexible joint robot manipulators. This nonlinear observer scheme is based on the sliding mode method. Sliding controllers have recently been shown to feature excellent robustness and performance properties for specific classes of nonlinear tracking problems. Dynamic equations of flexible joint robot manipulators are derived from the Euler-Lagrange equations by forming the corresponding Lagrangian. Simulation results are presented to show the validness of the proposed nonlinear observer scheme.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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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.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.11
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• pp.3066-3074
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• 1994

This paper addresses the residual vibration problem of robots due to joint flexibility excited by fast accelerations, which has not been easily solved with conventional closed loop controllers. In this paper, an open loop input shaping technique, proposed by singer, has been applied to a 3 DOF robot with joint flexibility. In conjunction to the technique, a closed loop controller based on time-delay controller was also used. The results of simulations and experiments showed that the technique is quite effective for suppressing the residual vibration.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.101-106
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• 1997

This paper proposes a stable adaptive neural network control(NNC) for fixable joint manipulators. For designing the stable adaptive NNC, the flexible system dynamics is separated into fast and slow subdynamics according to singular perturbation concept. For the slow subdynamics, an adaptive NNC is designed to warrant the system stability and NN learning by lyapunov stability criterion. And to stabilize the fast dynamics, derivative control loop is installed. Through numerical simulation, the performance of the proposed NNC was compared to that of an adaptive controller designed based on the knowledge of the system dynamics. The proposed NNC shows much improvement over the conventional adaptive controller.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.559-562
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• 2005

When we analyze dynamics of a multi body system, a compliance of joints must be considered. If the virtual model for CAE(computer adied engineering) analysis is not considered compliance, the result of CAE analysis will be very different from the actual result. Especially in a biped walking robot, a compliance can be caused in joints of a walking robot, and the robot may lose walking stability. This paper proposes a compliance modeling method and the effectiveness of the compliance model is verified through experiments.