1996 Volume 116 Issue 10 Pages 987-992
We consider the problem of applying H∞ optimization techniques to design a TDOF controller for robust servo systems. We introduce a two-step H∞ optimization procedure: a feedback controller is designed to satisfy feedback properties and a prefilter is used to improve reference tracking performance. We describe a mixed sensitivity optimization scheme that is used for the feedback controller design, and propose a frequency shaping philosophy that highlights key issues for the prefilter design. We discuss the uncertainties in DC motor model and explain how to treat the parametric and non-parametric uncertainties in H∞ optimization framework. We also show a design example for a DC motor with parametric uncertainties and analyze the tracking property in terms of design strategy and parameters change.