Frequency Domain Based Fractional Order Modeling of IPMC Actuators for Control

Abstract

Ionic polymer metal composite (IPMC) actuators have promising applications in robotics and microrobotics in a not distant future, but this will require a deep knowledge in different aspects, such as manufacturing, material characterization and control strategies. In this paper, frequency responses of several IPMC actuators, cut from the same IPMC bulk sheet with a micro laser etching machine, are obtained experimentally by measuring the tip deflection by means of a laser distance meter. Models, consisting of a fractional integrator in series with a resonant system of both fractional and integer order, are identified in the frequency range [0.11, 30] Hz for each sample of IPMC. The results show that models with these structures can be adequate for control purposes.