Emulation design based linear quadratic regulation

Abstract

With the encouraging rapid advancement in digital controller design, there is a need to explore further the optimal and robust digital controller implementation schemes. The ease in implementation of the discrete time controller urge the designers to adopt the emulation design technique, in which discrete-time systems are treated in a continuous-time framework. In emulation design, a discrete-time controller is obtained after the discretization of continuous-time controller at a high sampling rate. Keeping in view the valuable advantages of emulation design, a linear discrete time closed loop structure is proposed with emulation design based linear quadratic regulator (LQR). The suggested scheme provides optimal tracking of a reference signal even in the presence of external disturbances. Prior knowledge about the external disturbance is utilized by the control scheme to effectively minimize its effect on the system. Through computer simulations, a comparison is also drawn between the proposed emulation based control scheme and the corresponding continuous-time control scheme. Results shows that sampling time and weighing parameters of the cost function play important roles in defining the system performance.