Morphological compliance enables robot locomotion through cluttered terrain

The remarkable ability of animals, such as mice, cockroaches and spiders, to manoeuvre through challenging cluttered natural terrain has been a primary inspiration for legged robots. Recent research indicates that body reorientation along pathways of minimal energy is a key factor influencing such locomotion. We propose to extend this idea by hypothesizing that soft bodied animals and robots could employ an alternate yet equally effective strategy relying on their distributed body compliance to squeeze through cluttered obstacles. To demonstrate the same, we have developed a palm-scale, origami-based hexapedal robot, Compliant Legged Articulated Robotic Insect (CLARI) with compliant exoskeletal morphology. The robot, fabricated using a multilayer laminate laser micromachining technique, has six independently actuated two degree of freedom legs. Using this strategy, CLARI is able to passively conform to its environment and move through both horizontally and vertically confined spaces and requires only simple leg mechanics. We aim to verify our hypothesis by constructing a series of robots with varying body compliance and experimentally determining the preference for body deformation vs reorientation in a given cluttered environment for identical feedforward control commands.