Sensors and Actuators using Ionic Polymer Metal Composites for Micro Robot Applications

As the name implies, Ionic Polymer Metal Composite (IPMC) is a composite material, which deforms when exposed to an electric field. On the other hand it is capable of generating a voltage across the top and the bottom surfaces of the material, when subjected to mechanical deformations. Therefore IPMCs can be used as Soft Actuators as well as Soft Sensors. Mechanical flexibility and light-weight, make them 'Soft'. However, designing Soft Sensors using IPMCs requires accurate input-output models from the mechanical input to the electrical output. Similarly for Soft Actuator designs, models have to be derived from the electrical input to the mechanical output.

This paper uses cantilevered flexible beam model undergoing large deflections under a point load at the free end to model an IPMC Soft Sensor. The same cantilevered flexible beam model but under a uniformly distributed load undergoing large deflections is used to model an IPMC Soft Actuator. The principle of thermal expansion and contraction of a bi-metallic strip is used to model the motion action in both cases.

The structural and thermal multi-physics models, used to derive the deformations of complicated shapes of actuators are implemented for simulations using finite element methods. The simulations are verified experimentally using IPMCs manufactured locally.