Sectored Tube-Shaped Ionic Polymer-Metal Composite Actuator With Integrated Sensor

This paper describes the development of a tube-shaped ionic polymer-metal composite (IPMC) actuator with sectored electrodes and an integrated resistive strain-based displacement sensor. Tube or cylindrical shaped IPMC actuators, with the ability to provide multiple degrees-of-freedom motion, can be used to create active catheter biomedical devices and novel bio-inspired propulsion mechanisms for underwater autonomous systems. An experimental tube-shaped IPMC actuator is manufactured from a 40-mm long Nafion polymer tube with inner diameter of 1.3 mm and outer diameter of 1.6 mm. The outer surface of the tube-shaped structure is plated with platinum metal via an electroless plating process. The platinum electrode on the tube’s outer surface is sectored into four isolated electrodes using a simple surface milling technique. A custom-designed strain sensor comprised of 50 AWG ni-chrome wire is developed and attached to the tube’s surface to sense the bending motion of the tube actuator. The integrated sensor is low cost and practical, and it avoids the need for bulky external sensors such as lasers for measuring deflection and feedback control. Preliminary experimental results are presented to demonstrate the performance of the IPMC tube actuator and integrated displacement sensor.