Improved Periodic Output Feedback control method for creep characteristic of thick IPMC plate

IPMC (ionic polymer metal composites), also known as artificial muscles, is one kind smart material of electric actuators, it can generates a large deformation under a relatively low input voltage (generally less than 5V). Thin IPMC strips (the thickness is usually less than 0.3mm) possess a strong hysteresis and creep characteristics which will change with the different level of water content and the environmental temperature. When it comes to thick IPMC samples (the thickness is thicker than 0.4mm), the hysteresis characteristic is relatively weaker than the creep characteristic and these properties relatively remain stable. Currently, most of the existing control methods for IPMC manipulation are complicated and they are usually adaptive ones which require complicated hardware equipments, so these kinds of controllers are not very suitable for some practical applications. This paper proposes the Periodic Output Feedback (POF) control method to regulate the IPMCs, and also develops the error integral compensation POF (IPOF) control method to deal with the gradual enhancing control error and the output oscillation problems of IPMCs with POF controller. The simulations and experiments are carried out, and good results are obtained.