Offset elimination using receding horizon controllers: a comprehensive analysis

GONZÁLEZ, ALEJANDRO HERNÁN; ADAM, EDUARDO; MARCHETTI, JACINTO LUIS

Buenos Aires, Argentina

Congreso; XXº Congreso Argentino de Control Automático (AADECA 2006); 2006

Abstract: An offset free control is one that drives the controlled outputs to their desired targets at steady state. In the linear model predictive control (MPC) framework, the elimination of steady state offset may seem a little obscure, since the closed loop optimization tends to hide the integral action. Theoretically, implementing a well posed optimization problem and having unbiased prediction in steady state are sufficientconditions to eliminate offset output. However, these basic conditions are not always achieved in practical applications. This paper presents a detailed practical analysis of the existing strategies to eliminate offset when linear models with moderated uncertainties are controlled. In addition, these strategies are used for a Continuous Stirred Tank Reactor (CSTR) control with nonlinear dynamic, in order to evaluate the formulations in a more realistic process.