Tracking Control for Robot Manipulators Exploiting Time-Delay Estimation

In this paper, a weak model dependent robust controller is proposed for robot manipulators to address modeling errors and disturbances and then to improve tracking accuracy. Firstly, the mathematical model of the robot manipulator is established according to the Euler–Lagrange equation. To address modeling errors and disturbances, the controller is designed by the time-delay estimation (TDE) method. Besides, in order to further reduce the tracking error, a linear quadratic regulator (LQR) auxiliary controller is designed and then the original error is corrected. In addition, the stability of the closed-loop system is strictly analyzed using the Lyapunov theorem. Finally, a series of experiments is conducted on a 6-DOF robot manipulator. It is shown that the weak model dependent robust controller proposed in this paper tracks the reference trajectory more accurately, and the tracking error is significantly lower than classical controllers. The proposed control method will serve as a reference for controller design of high-precision robot manipulators.