Non-minimum phase properties and feedback linearization control of nonlinear chemical reaction

Non-minimum phase objects cause problems in designing control systems due to unstable inverse dynamics. In the case of, considered in the paper, Van de Vusse nonlinear chemical reaction, non-minimum phase properties are in connection with the input multiplicity of the process. Control method proposed for this process relies on feedback linearization and linear quadratic control. Input-state linearization provides an exact linear model. Linear quadratic regulator uses obtained model and determines appropriate control law. This approach, providing that weights for the linear quadratic regulator are adjusted properly, delivers control system with good performance of output and state signals, despite the fact that the output of the process is not a state variable of the linear model. The solution also assures stability of the system.