Design of output tracking via variable structure system: for plants with redundant inputs

A generalised output tracking design for affine nonlinear system via variable structure system is proposed. It is shown that if the left-invertibility condition for affine nonlinear system with unequal numbers of input and output channels is satisfied, then the system outputs can be controlled to track the desired smooth trajectory. Moreover, the redundant inputs are used to improve the tracking performance of the system. Example illustrate the design processes.