Control theory and applications

Abstract

In this chapter, a presentation of control theory and engineering as applied to ocean engineering is given. The chapter starts with the fundamentals of systems science and theory, i. e., descriptions of systems in state space and for linear, timeinvariant ones in the frequency domain using the Laplace transform as well as with ordinary differential equations with respect to time. Then stability, controllability, and observability with an emphasis to linear, time-invariant systems are presented. Bode plots for sinusoidal steady-state analysis as well as the root locus technique for proportional gain feedback design are presented. For single-input, single-output systems, PID control is introduced as both a pole placement problem as well as in the framework of conventional Ziegler- Nichols methods. Pole placement design with the addition of Luenberger observers is presented for linear, time-invariant systems with any time of inputs and outputs. A brief presentation of digital controller implementations is given. Applications from ocean engineering include control of autonomous underwater vehicles and autopilots for surface vessels.