OPTIMIZATION OF A CONTROL ALGORITHM USING A SIMULATION PACKAGE

The classic PID controller has a number of advantages over more sophisticated controllers in that it is simple and well understood by engineers in industry. it does however send conflicting signals from the three separate functions to the controller. Phelan has shown that a better controller (pseudo differential feedback, PDF) can be produced using the principle of one master, which gives significantly better results for some applications. This paper outlines a simulation program which is used to derive optimal gains for this and other SISO linear and non-linear controllers for any physical system which can be modelled in ACSL, the simulation language used. The system description and the type of optimal criterion can be changed easily by editing the program file. Validation of the program was made by comparing the computer solution with several analytical solutions. The best response for a simple integral process and a PDF controller, for example, was given by an integral of time squared times error squared criterion. The controller gains do not vary greatly for the various criteria for the same process, so that near optimal performance can be achieved by using any criterion to derive the gains.