Ionic polymer metal composite is a class of electro-active polymers that are becoming more significant as smart actuators due to their large bending deflection, mechanical flexibility, low excitation voltage, low density, and ease of fabrication process. These properties make IPMCs suitable for a variety of application fields such as robotics, aerospace, biomedicine etc. There are a lot of linear and nonlinear models which describe actuation properties of IPMC. These models’ parameters may be obtained by various identification methods in which only a very few are nonlinear. Besides, there has been no model that explains all the physical phenomena associated with this actuator. In this paper, a new identification method is presented which incorporates a nonlinear with linear least squares method. This method is implemented on a nonlinear model. This model in comprised of two steps; as a first step, nonlinear relationship between the absorbed current and the voltage applied and as a second step relationship between the absorbed current and the blocked force are determined. The first and second steps are identified using a nonlinear and linear least squares methods, respectively.
