Abstract:
The diving industry presents an exciting opportunity for developments in sensorbased underwater motion capture. Whether in terms of respiration monitoring, diver-diver communication or interaction with underwater robotics, motion capture has the potential to enhance the underwater experience. While several sensing technologies have potential in this area, dielectric elastomer strain sensors are excellent candidates due to their intrinsic characteristics of being soft, light-weight, and compliant. Before implementing dielectric elastomer sensors into underwater applications, their performance was first evaluated in fresh and salt water. This included analysis of the fringing field, water and salt absorption, sensor signal drift, salinity-dependence, temperature-dependence, and dynamic electrode resistance. Electrostatic simulations were performed to assess a wide-range of sensor geometries and develop a shielded sensor design suitable for large scale fabrication techniques. While much focus in sensor-based motion capture is often on the sensor itself, the electrical connection both to the electronics and internal electrodes of the sensor were also areas requiring improvement. A wireless approach was implemented which allowed both the sensor and electronics to be completely encapsulated without wires or glands projecting out. Further, this approach allowed for a modular system where sensors and connections could be replaced easily even underwater. This thesis details the considerations taken into account in the development and fabrication of a strain sensor specifcally designed for underwater motion capture.