ROBUST DISCRETE-TIME TRACKING CONTROL USING SLIDING SURFACES

This paper deals with the robustness issues associated with the feedforward tracking control with respect to unmodeled plant uncertainties. Based on the Diophantine equation, a new discrete time sliding functions has been defined and utilized for the robust feedforward tracking control law. The robustness is achieved by using a sliding function-based nonlinear feedback. As for model/plant mismatches the plant order uncertainty and parameter uncertainty are taken into account for robustness analysis. Noncircular machining has been adopted as an application example of this algorithm. Through computer simulation it has been shown that the robust discrete time tracking control is effective for unmodeled plant uncertainties.