Operator based Robust Nonlinear Control Design to an Ionic Polymer Metal Composite with Uncertainties and Input Constraints

In this paper, robust nonlinear control design to an ionic polymer metal composite (IPMC) with uncertainties and input constraints is studied. The IPMC is a novel smart polymer material, and many potential applications for low mass high displacement actuators in biomedical and robotic systems have been shown. In general, the IPMC has highly nonlinear property, and the control input is subject to some constraints to ensure safety and longer service life of IPMC. Moreover, there exist uncertainties caused by identifying some physical parameters and approximate calculation in dynamic model. As a result, considering measurement error of parameters and model error, a practical nonlinear model is obtained, and a nonlinear robust control design with uncertainties and input constraints using operator-based robust right coprime factorization is proposed. The effectiveness of the proposed control method based on obtained nonlinear model is confirmed by simulation and experimental results.