Chapter 25. Multiphysics Modeling and Simulation of Dynamics Sensing in Ionic Polymer Metal Composites with Applications to Soft Robotics

Abstract

Since their discovery in the early 1990s ionic polymer metal composite (IPMC) actuators and sensors have been the focus of extensive research from various perspectives, including fabrication, actuation and sensing, energy harvesting, modeling, control and applications. From the fabrication perspective, investigators have studied various methods for improving the performance of IPMCs to gain higher ionic activity in a wider range of conditions. In addition, various theoretical models have been presented to explain the ionic electroactivity of IPMCs. Meanwhile, the spectacular properties of IPMCs, such as flexibility and large deflection amplitude, have opened the way for a multitude of new applications. In terms of performance, the electromechanical responses of the IPMCs vary significantly when using different types of ionic polymers and electrodes. The first part of this chapter pertains to various types of ionic polymers, electrodes and diluents that have been studied in the literature for the fabrication of IPMCs. Next, the dynamic sensing responses of IPMCs are studied. The high sensitivity of IPMC sensors to applied deformations as well as their flexibility make IPMCs promising candidates for the sensing of dynamic curvature variations in structures. We review the dynamic response of an IPMC sensor strip with respect to controlled curvature deformations subjected to different forms of input functions and rates. The next part of this chapter is dedicated to the application of IPMC curvature actuation in biomedical instrumentation, where soft actuators with low actuation voltages are of high interest. Biocompatible IPMC actuators can improve the design and dexterity of active catheters and robotic forceps by introducing smaller and soft robotic end-effectors. We will review the designs and actuation mechanisms of the single DOF and two DOF bio-inspired ionic actuators required for bio-robotic applications. Finally, a theoretical physics-based model based on Poisson–Nernst–Planck equations is studied to explain the observed ionic electroactivity and dynamic phenomena, such as the rate dependency of IPMCs.