MULTIVARIABLE NONLINEAR CONTROLLER SYNTHESIS IN DISCRETE-TIME

For a nonlinear process with a generically singular characteristic mat rix, input-output linearization is usually not achievable with a stati c state feedback, and one has to use a dynamic state feedback. A syste matic and general approach to input-output linearizing feedback contro l of nonlinear processes with a generically singular or nonsingular ch aracteristic matrix is presented. Mixed error- and state-feedback, err or-feedback, and mixed error- and output-feedback control laws are der ived. The derived feedback control laws reject step disturbances asymp totically and induce linear, input-output, closed-loop behavior to the process under consideration. The theoretical connections between the derived control laws and (a) model predictive control and (b) several already-available linear deadtime compensation methods are established . The application and performance of the derived control laws are illu strated and compared with those of model predictive control, by numeri cal simulation of a chemical reactor. (C) 1998 Elsevier Science Ltd. A ll rights reserved.