Iterative learning control of robot manipulator with I-type parameter estimator

This paper presents an iterative learning control (ILC) scheme for uncertain robotic systems that perform the same tasks repetitively. The proposed ILC scheme comprises a feedback controller and a feedforward learning controller using an integral-type(I-type) parameter estimator. In contrast with other ILC schemes, where the parameter estimates are varying in time, the proposed parameter estimator is invariant in time. Even with the time-invariant estimator, the entire profiles of position and velocity error trajectories during the operation time converge uniformly to zero as the number of iterations goes to infinity