H∞ Controllers With a PID Structure

Abstract

A review is given of the new H∞ Observations Weighted (HOW) optimal control law. The conditions under which the H∞ controller has a PID structure are identified and some implications for PID controller design are discussed. The simple form of this H∞ control law makes it easy to analyse and design. Examples are presented of the design procedure which involves the specification of the cost-function weighting transfer functions. The controller may be applied in applications where fast computational procedures are important.