Observer-controller design for a class of stable/unstable inverse response processes

This paper proposes the use of a two-degree-of-freedom configuration aimed at the control of inverse response processes. An observer-controller scheme based on coprime factorization results in a Smith-type predictor well suited for both stable and unstable inverse response processes. The design procedure is carried in two steps. First, the controller is designed providing an adjustable parameter to cope with the reference input tracking. Second, the observer blocks are selected for closed-loop properties, offering another tuning parameter to compromise between robust stability and disturbance rejection performance. As a result, the nominal set point response is decoupled from the disturbance response. To show the applicability of the proposed control configuration, its performance is compared by simulation with different approaches. © 2009 American Chemical Society.