Energy Harvesting in Soft Materials

There is a growing demand to increase energy efficiency in robotic applications. Although energy density in batteries has been steadily increasing, a long-duration mission with onboard energy storage increases the weight and volume of the robotic platform. In an underwater robot, an onboard power supply may add to the overall weight of the robot but is offset by the corresponding increase in buoyancy. Nonetheless, it is of interest to avoid recovering underwater robots to swap or re-charge batteries. Prolonged deployments of soft underwater robots can be achieved by harvesting energy from fluid-structure interactions. For example, energy can be harvested using piezoelectric or triboelectric effect. This talk will focus on ongoing dynamic modeling and control of piezoelectric energy harvesting in soft underwater robots. We use planar Discrete Elastic Rod theory combined with an equivalent circuit models of a piezoelectric device to describe energy generation during stretching and bending motion of a soft robotic appendage in a fluid. Parametric studies are planned to determine the optimal energy generation and performance. This work seeks to open new areas for improved energetics of underwater robotics, particularly those constructed from soft, flexible materials.