Influence of Joint Actuator Dynamics on Sliding Mode Controlled Flexible Manipulators

This paper investigates the influence of unmodeled dynamics of joint actuators on sliding mode controlled two-link flexible manipulators. The joint actuators are modeled as singularly perturbed systems and a linear combination of joint angular and flexible modes is chosen as a new output, which can decompose the whole system into an input-output subsystem and a zero dynamic subsystem for the indirect control of tip-position. For the input-output subsystem, the influence of joint actuator dynamics on the system stability is investigated; while for the zero dynamic subsystem, its stability is proved to be related to the redefined parameters. Finally the Lyapunov stability theory is used to determine the steady error of tip-position for each link. Simulations validate this paper.