Design of Digital Feedforward/Preview Controllers for Processes With Predetermined Feedback Controllers

Abstract

This paper deals with the design of digital feedforward/preview (F/P) controllers for multi-input, multi-output processes with predetermined feedback controllers. The feedback controller is assumed to include an integral action which operates upon the error between setpoint and process output. The feedforward/preview controller is a weighted sum of previewed values of future disturbances. Formula for the F/P control gains are derived using a parameter optimization technique to minimize a quadratic cost criterion. Simulation examples are included to show some of the consequences of the developed design method.