An adaptive sliding mode-like P-type iterative learning control for robot manipulators

Iterative learning control(ILC) is used to track the trajectory of repetitive motion, especially for industrial robot. The proposed control scheme is based upon the feedback of tracking error and corresponding change rate, which construct a switching surface, with the use of a proportional structure, for which it is called sliding mode-like P-type ILC. In addition, an adaptive item was added to not only cope with the unknown parameters and disturbances but also. remove chatter phenomenon happening in control process. To verify the proposed control law, a conventional PD ILC and an adaptive PD ILC are added as comparison with all the same setting conditions. We use root mean square error (RSME) each iteration trial as performance evaluation index. Finally, simulation results are provided to illustrate the effectiveness of the proposed controller. As a result, it can achieve better performance.