Trajectory tracking of robot using a fuzzy decentralized sliding-mode tracking control

A proportional control is first applied to improve the dynamics of robotic system. It is called "improved robotic system (IRS)", containing N subsystems. Each subsystem is approximated by the weighted combination of L linear pulse transfer function systems (LPTFSs). For every nominal LPTFS of the ith subsystem, a dead-beat to its sliding surface is first designed. The output disturbance is not small and contains various frequencies. In this situation, the H^∞-norm of the weighted sensitivity function between the mth sliding surface and the output disturbance is minimized. An appropriate selection of the weighted function can enhance the system robustness. Although the effect of the output disturbance is attenuated, a better performance can be improved by a fuzzy switching control. Finally, the experiments of the trajectory tracking of the IRS on the horizontal plane with (or without) payload are given to verify the usefulness of the proposed control.