Introduction

Abstract

Over the last thirty years or so, control has become a well recognised branch of engineering, establishing itself over an enormous range of disciplines and applications. That range increased still further with the advent of the microprocessor; inexpensive ‘intelligence’ became suddenly and extensively available. Unfortunately digital techniques have not proved easy to apply. Those very features that make the microprocessor so attractive also make it difficult to employ; there are a greater number of important decisions to be made when designing a digital controller than when designing an analogue one.