Comparison of Two Methods of Incorporating an Integral Action in Linear Quadratic Regulator

Comparison of two Methods of incorporating an integral action in the linear quadratic controller is presented. First Method of incorporating an integral action in linear quadratic regulator (LQR) is augmenting system matrix with error in sate variable. Second Method of incorporating integral action is introducingu in performance index instead of u to get multivariable proportional plus integral controller. For comparison of both the Methods state space model of two CSTR's in series is used for simulation studies. A MATLAB code is developed for solving nonlinear matrix equations.