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

This paper presents an approximate design scheme using delta-operator of multi-rate model reference adaptive control (MRAC) for an electro-pneumatic servo system. Since the discrete-time plant of the electro-pneumatic servo system often becomes non-minimum phase, it is impassible 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.