Harvesting Thermal Energy for Microid Microrobots

A. Shankar, F. Li, and J.V. Clark
Purdue University, West Lafayette, IN, USA

In this paper we present a computational study on harvesting thermal energy to electrically recharge microid microrobots. Microids are microrobots that have insect like dexterity. We examine the feasibility of extracting energy from the ambient environment through the piezoelectric legs of the microid. The microid’s use in remote locations makes it imperative for it to be able to recharge itself. Clark et al. presented a novel design for the microid with “solid state muscles” comprised of three piezoelectric flexures for each leg. We use Lead Zirconate Titanate (PZT) as the piezoelectric material because of its high piezoelectric constant. Through modeling and simulation using COMSOL, we subject the leg to expected vibrations caused by the ambient, and we harvest the piezoelectric-generated electrical energy through electrical circuits. The mechanics is modeled with finite element analysis, and the coupled electronics is modeled with lumped element analysis. We modify the microids resonant frequency by having it grasp onto objects of various mass, and we compare it to an experimental study on energy harvesting using Lead Zirconate Titanate by Sodano et al.