Development of Dielectric Electroactive Polymer Actuator for Robotic Applications

Abstract

This paper presents a compliant actuator based on Dielectric Electroactive Polymer (DEAP) technology. The presented advanced robotics concept requires smart materials, mostly in the form of actuators, for the development of biomimetic and flexible robotic systems. Smart materials such as Shape Memory Alloys (SMAs) and Electroactive Polymers (EAPs) are promising candidates for developing Bio-inspired smart robots without using conventional rigid links and joints. However, a major issue with SMAs is their slow response and limited bandwidth. The actuator made of DEAP is composed of a pre-stretched silicon film sputtered with very thin silver electrodes on both sides so as to form a smart capacitor as explained in patent [1, 20]. When an electric field is applied across the capacitor, the silicon film, which is of highly deformable dielectric medium, strains in the direction of application of voltage due to electrostatic pressure. Hence, thickness of the capacitor reduces that leads to corresponding enlargement of area in the other two directions. Different varieties of DEAP actuator models have been studied by various researchers for large displacement, precision motion and for associated control difficulties. Some of the applications are given in patent [23-28]. The experimental results obtained show that a suitable nonlinear control algorithm is required for obtaining accurate results. The suitability of DEAP actuator towards development of a spatial compliant mechanism is discussed and presented here. Keywords: DEAP actuator, electrostatic pressure, shape memory alloy, smart materials, spatial compliant mechanism, EAP material, Actuation Process, electrode, voltage