Bending Curve Modeling of Ionic Polymer Metal Composites in Soft Actuator Applications

Ionic polymer metal composites (IPMC) may be used to replace the electro-mechanical actuators in a vast variety of application areas ranging from biomedical devices to soft actuators and sensor systems in modern humanoid robotics. The excellent characteristics shown by IPMCs are highly influenced by their interrelated mechanical, electrical and chemical properties. However, this makes it complicated and difficult to understand the physics and predict their behavior. In order to utilize the full potentials towards advanced engineering, there is an increasing need to investigate their actuation mechanism and derive means of predicting the behavior. The object of this paper is to characterize and model the bending motion of the strip-type IPMC actuators using the theory on large deflections of beams. After deriving a mathematical model approximately accounting for mechanical, electrical, and chemical properties and geometric parameters of the actuator, the model has been experimentally verified for an actuator with the dimensions 25 mmtimes2.6 mmtimes0.44 mm. Theoretical and experimental results are presented to demonstrate that the model is effective enough to predict the displacement output of the strip type-IPMC actuator all along the edge of the actuator as a function of the applied voltage.