An expert PID controller

The authors report on the development of an expert PID (proportional-integral-differential) controller for industrial processes. It uses the optimal property of a certain region in the P, I, and D parameter space providing minimum integrated (average) error when the required damping is ensured otherwise. The expert system uses an algorithm which basically modifies the settings of a conventional real-time PID controller continually until the parameters enter the optimum region mentioned above. The optimum region for a given process depends on the characterization of that process which is carried out in a simple indentification procedure prior to convergence. The authors describe the theory, the algorithm used, the hardware, and the software aspects of the implementation of the expert system as well as the test results obtained on a simulated process control system