Static Output Feedback Variable Structure Control

Chapter 3 considers static output feedback controller design for both nonlinear systems and interconnected systems. For a class of fully nonlinear systems, a variable structure control based Lyapunov method is proposed to drive the system to a ‘small’ region of the origin and maintain motion in the region thereafter. Then, in the region, the nonlinear system is linearised and a sliding mode control is designed to stabilise the system asymptotically. Both the controllers combined to stabilise the system globally. For interconnected systems, decentralised control schemes are developed and output variables embedded in the nonlinear terms are separated and used in the control design to reduce conservatism. Case studies based on a mass–spring system, coupled inverted pendulums and a flight control system are provided to show the developed control methodologies.