Nonlinear systems can be linearised around operating points and the behaviours in the neighbourhoods of the operating points are then approximated by their linearised models. The domain for a locally linearised model can be fairly small, and this may result in that a number of linearised models are needed to cover an operating range of a system. In this chapter, we will introduce another method to obtain a linear model for nonlinear systems via feedback control design. The aim is to convert a nonlinear system to a linear one by state transformation and redefining the control input. The resultant linear model describes the system dynamics globally. Of course, there are certain conditions for the nonlinear systems to satisfy so that this feedback linearisation method can be applied.

Chapter Contents:

• 6.1 Input-output linearisation
• 6.2 Full-state feedback linearisation

Inspec keywords: nonlinear control systems; linear systems; approximation theory; feedback; control system synthesis; linearisation techniques

Other keywords: state transformation; approximation theory; feedback linearisation; nonlinear systems; feedback control design; operating points; linearised models

Subjects: Interpolation and function approximation (numerical analysis); Control system analysis and synthesis methods; Nonlinear control systems