Analysis and design approach to inchworm robotic insects

Abstract

An inchworm robotic insect is presented that can displace on a smooth horizontal surface. It consists of a piezoelectric unimorph and two custom-designed limbs. A two-module lumped-parameter model is formulated to assist in the design/analysis process. The geometry of deformation is analyzed first by superimposing the unimorph's elastic deformation to a rigid-body rotation around the limb/ground contact point A geometry configuration is thus identified that maximizes the horizontal displacement of the robot over one motion's cycle. The dynamic module allows simple evaluation of the ground reaction forces and horizontal velocity of the robot's center of gravity. A prototype inchworm robotic insect was designed whose behavior exhibited good agreement with theoretical predictions.