Ionic polymer-metal composites for underwater operation

The ionic polymer-metal composite (IPMC) for flexible hydrodynamic propulsor blades can provide many new opportunities in navy platforms, especially in unmanned, robotic vehicles used in surveillance and combat. When in operation, the IPMC materials are very quiet since they have no vibration causing components, i.e., gears, motors, shafts, etc. For small autonomous underwater vehicles (AUV), this feature is truly attractive. IPMCs are friendly to solid-state electronics and have digital programming capabilities; thus, active control is possible. Another advantage of these materials is that they can be operational in a self-oscillatory manner. However, there are several issues that still need to be addressed: propulsor design, testing, robotic control, and the theoretical modeling of the appropriate design. Currently, the IPMC is being investigated for propulsor blade applications and a propulsor model with a robust control scheme. An analytical model of a segmented IPMC propulsor was formulated to be a building block for accommodating the relaxation behavior of IPMCs and for describing the dynamics of the flexible IPMC bending actuator.