Multi-rate MRAC using delta-operator for electro-pneumatic servo system

This paper presents an approximate design scheme using delta-operator of multirate model reference adaptive control (MRAC) for an electropneumatic servo system. Since the discrete-time plant of the electropneumatic servo system often becomes nonminimum phase, it is impossible to construct the conventional design scheme of MRAC for such a plant. Adopting a delta-operator and neglecting the small coefficients of the plant, the approximate design scheme of MRAC is constructed to overcome the above problem. In this design scheme, the update-time of the controller parameters is chosen to be integral times the sampling-time to supply the lack of the update-time. Effectiveness of this design scheme is confirmed by experiments using the existent electropneumatic servo system