Autotuners based on the Smith predictor structures

Abstract

This paper presents a set of autotuners for single input-output systems with time delay. Autotuners represent a combination of relay feedback identification and some control design method. In this contribution, models with up to three parameters are estimated by means of a single asymmetrical relay experiment. Then a stable low order transfer function with a time delay term is identified. Controller parameters are analytically derived from a general solution of Diophantine equations in the ring of proper and stable rational functions RPS. This approach covers a generalization of PID controllers and it enables to define a scalar positive parameter for further tuning of the control performance. The Smith predictor scheme is applied for systems with a time delay term. The simulations are performed in the Matlab environment and a toolbox for automatic design and simulation was developed.