Towards improving positioning accuracy of conducting polymer actuators

Recently, there have been significant developments in conducting polymers, particularly in their synthesis and use as electromechanical actuators. This is mainly due to their many promising features including biocompatibility, high force to weight ratio, suitability to open loop control. On the other hand, they suffer from nonlinear problems such as hysteresis and creep. With this in mind, it is the aim of this study to evaluate the existence level of these nonlinearities and their mathematical modeling in order to improve the positioning accuracy of conducting polymer actuators. The polymer actuator considered in this study which has a symmetrical structure can operate in both liquid and non-liquid media as opposed to its predecessor. The actuator drives a rigid link, like positioning a payload. The experimental results demonstrate that while the hysteresis is negligibly small, the level of the creep is significant enough to model it and subsequently employ the model to improve steady-state positioning of the actuator. Based on experimental results, a viscoelastic model is employed to describe the creep behaviour. The outcomes of this study will pave the way towards understanding of the limitations as well as potential usefulness of conducting polymer actuators in many cutting edge applications ranging from biomedical to micro/nano manipulation systems.