Introduction

This introductory chapter provides an overview of time-delay systems. Time-delay systems, also called systems with after-effect or dead-time, hereditary systems, equations with deviating argument, or differential-difference equations, are ubiquitous in practice. Some representative examples are found in chemical industry, electrical and mechanical engineering, biomedical engineering, and management and traffic science. The most common forms of time delay in dynamic phenomena that arise in engineering practice are actuator and sensor delays. Due to the time it takes to receive the information needed for decision-making, to compute control decisions, and to execute these decisions, feedback systems often operate in the presence of delays. The chapter then illustrates the possible methods in control of time-delay systems. This book develops adaptive and robust predictor feedback laws for the compensation of the five uncertainties for general linear time-invariant (LTI) systems with input delays.