Microfluidic Circuit Dynamics and Control for Caterpillar-Inspired Locomotion in a Soft Robot

Abstract

Because caterpillars can locomote through complex terrain, caterpillar-inspired soft robots promise safe and reliable access for search, rescue, and exploration. Microfluidic components analogous to electronic components like resistors and capacitors further promise the principled design and fabrication of autonomous soft robots powered by microfluidic circuits. This paper presents a model for caterpillar locomotion using an oscillator network approach, in which the periodic motion of each leg is described by an oscillator, and the collection of all legs forms a network. We use tools from graph theory to model (1) a first-order system consisting of a network of RC oscillators connected to an astable multivibrator circuit serving as a Central Pattern Generator (CPG); and (2) a second-order system consisting of a network of RLC oscillators with a deCentralized Pattern Generator (dCPG) as reference control. For the RC network, we analyze the rate of convergence and the gait number, a metric that characterizes the locomotion gait. For the RLC network, we design feedback laws to stabilize consensus and traveling wave solutions. Numerical modeling and preliminary experimental results show promise for the design and control of locomotion circuitry in a caterpillar-inspired soft robot.