Title :
Adaptive Output Feedback Control of Flexible-Joint Robots Using Neural Networks: Dynamic Surface Design Approach
Author :
Yoo, Sung Jin ; Park, Jin Bae ; Choi, Yoon Ho
Author_Institution :
Dept. of Electr. & Electron. Eng., Yonsei Univ., Seoul
Abstract :
In this paper, we propose a new robust output feedback control approach for flexible-joint electrically driven (FJED) robots via the observer dynamic surface design technique. The proposed method only requires position measurements of the FJED robots. To estimate the link and actuator velocity information of the FJED robots with model uncertainties, we develop an adaptive observer using self-recurrent wavelet neural networks (SRWNNs). The SRWNNs are used to approximate model uncertainties in both robot (link) dynamics and actuator dynamics, and all their weights are trained online. Based on the designed observer, the link position tracking controller using the estimated states is induced from the dynamic surface design procedure. Therefore, the proposed controller can be designed more simply than the observer backstepping controller. From the Lyapunov stability analysis, it is shown that all signals in a closed-loop adaptive system are uniformly ultimately bounded. Finally, the simulation results on a three-link FJED robot are presented to validate the good position tracking performance and robustness of the proposed control system against payload uncertainties and external disturbances.
Keywords :
Lyapunov methods; actuators; adaptive control; closed loop systems; control system CAD; feedback; flexible manipulators; manipulator dynamics; observers; recurrent neural nets; robust control; uncertain systems; Lyapunov stability analysis; actuator dynamic; actuator velocity information; adaptive output feedback control; closed-loop adaptive system; flexible-joint electrically driven robot; link position tracking controller; observer backstepping controller; observer dynamic surface design technique; robot dynamic; robust output feedback control; self-recurrent wavelet neural network; Adaptive observer; dynamic surface control (DSC); flexible-joint electrically driven (FJED) robots; output feedback; robust control; self-recurrent wavelet neural network (SRWNN); Algorithms; Computer Simulation; Feedback; Joints; Models, Theoretical; Motion; Neural Networks (Computer); Numerical Analysis, Computer-Assisted; Robotics;
Journal_Title :
Neural Networks, IEEE Transactions on
DOI :
10.1109/TNN.2008.2001266