ABSTRACT
This chapter discusses linear quadratic tracking (LQT) systems, and some related topics in the linear quadratic regulator theory. It also discusses the fixed-end-point state regulator system, where the final state x is zero and the final time tf is fixed. The chapter examines the state regulator system with infinite time interval and with a specified degree of the stability for a time-invariant system. It explores the frequency domain to derive some results from the classical control point of view for a linear, time-invariant, continuoustime, optimal control system with infinite-time horizon case. The chapter provides some of the classical control features such as gain margin and phase margin for the closed-loop optimal control system. In classical control theory, the features of gain and phase margins are important in evaluating the system performance with respect to robustness to plant parameter variations and uncertainties.
