Adaptive Control for Redundant Robot Manipulators With Input Delay

Abstract This paper presents a novel task-space adaptive controller designed to accurately track the trajectory of the end effector in redundant robot manipulators. The developed controller effectively mitigates disruptions caused by input delay while also coping with parametric uncertainties and unknown time-varying additive disturbances within the system dynamics. The designed controller distinguishes itself from traditional joint space controllers by eliminating the need for solving position-level inverse kinematics at each sampling interval, as it employs a novel error dynamics. Furthermore, the controller differs from predictor-based approaches by incorporating a developed auxiliary error signal derived from integrating the input signal over a defined time window from the current to the delayed time, thereby removing the need for future state predictions. The designed controller guarantees the semiglobal uniform ultimate boundedness of the tracking error using a novel Lyapunov-based stability analysis. Numerical simulations conducted on a two-degree-of-freedom planar robot manipulator model validate the effectiveness of the proposed method.