Robustness analysis of composite adaptive robot control

Abstract

Composite adaptive control (CAC), an integrated direct and indirect adaptive control strategy, has been broadly applied to robots due to its superior control performance. This paper focuses on robustness analysis of CAC for a class of arm-type robots formulated by Euler-Lagrange systems. It is shown that CAC is still not robust against bounded perturbations without robust modifications. By incorporating a σ-modification, robustness against bounded perturbations of CAC is demonstrated in the Lyapunov sense such that parameter drift can be avoided. Simulation validations under external disturbances and measurement noises have been provided to verify the theoretical result.