Modeling and optimization of IPMC actuator for AutonomousJellyfish Vehicle (AJV)

摘要

Ionomeric Polymer Metal Composite (IPMC) actuators generate high flexural strains at small voltage amplitudes of 2-5V. IPMCs bend toward the anode when a potential drop is applied across its thickness. The actuation mechanism is due to the motion of ions which requires a form of hydration to dissociate and mobilize the charges. In our group, IPMCs are developed either as water-based or ionic liquid-based which is also known as the dry IPMCs. This combination of small voltage requirement with operation in both dry and underwater conditions makes the IPMCs a viable alternative for an Autonomous Jellyfish Vehicle (AJV). In this study, we model the IPMC actuator having curved geometry as thermal-piezoelectric equivalent bimorph beam using FEM model. We verify reliability of using thermal strain criteria to match the experimental deformation. The applied electrical voltage results in the charge accumulation on electrode surface that is used by a piezoelectric model to estimate the stress due to this charge accumulation and applied thermal strains by direct coupling to simulate the actuator structural deformation. We have designed an AJV with embedded IPMC actuators using this model to achieve the curvature of relaxed and contracted Jellyfish (Aurelia Aurita). Bio-mimetic deformation profile was achieved by using structural mechanics of beams with pre-built large deformation through application of +/-0.8V to optimized beam within 8.1% error norm in relaxed state and 21.3% in contracted state. This corresponds to -0.24% to 0.26% maximum flexural strait at maximum curvature point in contracted state.