Control of conducting polymer actuators without feedback: Simulated feedback control approach

Recently, there has been significant interest in conducting polymer actuators including their applications in micro devices and micro manipulation. A feedback control system is usually used to enhance the positioning ability of these actuators in order to widen their application areas. To this end, a feedback sensor is employed to acquire the position feedback information for implementing the control system. However, a feedback sensor is extremely large in size compared to the size of the conducting polymer actuators. With this in mind, this paper proposes a sensorless control scheme without the use of a position feedback sensor, which we call the simulated feedback control approach. It has a feedback loop based on the actuator model, not requiring a physical sensor. With an accurately identified system model, this control strategy has shown an excellent control performance when following a displacement input experimentally. The control performance of this control scheme has been compared to that of a feedforward-gain control scheme. The proposed control strategy can be extended to other smart actuators or systems, for which the use of a physical feedback sensor may not be practical.