Control of an input constrained nonlinear thermal system using a linear algebraic equivalence of nonlinear controllers

Feedback linearization (FBL) and sliding mode control (SMC) are two widely used control schemes for nonlinear systems, however, they can not be designed with explicit input constraints. In this paper, a general nonlinear optimal control design is provided which accommodates input constraints using a linear algebraic equivalence of the nonlinear controller (FBL/SMC). First, the linear algebraic equivalence of the nonlinear controller design is shown and then a nonlinear optimal controller is designed based on that equivalence. Quadratic programming and constrained linear least squares methods are used to solve the proposed control algorithm. The algorithm is applied to an ill-conditioned thermal process to illustrate the design process.