Model reference adaptive control and repetitive control for robot manipulators

A combination of adaptive and repetitive control for dynamic control of robot manipulators is introduced. The repetitive controller is a plug-in controller for connection to an existing model-reference adaptive controller. The input to the repetitive controller is the same as the adaptation error signal for the adaptive controller. In this scheme, desired trajectories and external disturbance are assumed to be periodic. Global stability for this control system is achieved and disturbance is rejected successfully. Based on the characteristics of the reference model, two types of control algorithm are presented: a unity-gain and a pure-integrator reference model. Discretized versions suitable for digital implementations, and sufficient conditions for their stability in the discrete time domain are presented. The performance of the adaptive and repetitive controller is demonstrated by simulation.>