A systematic approach to creating terrain-capable hybrid soft/hard myriapod robots

Multi-legged animals such as centipedes move effectively in diverse terrain. Their flexible body and limbs allow them to adapt their shape to the environment and traverse obstacles. To examine how the variation in body/limb forms of legged animals affects the mechanics of terrestrial locomotion, we built a multi-legged hybrid (soft/rigid) robot that has 8 segments (9 cm/segment), each with two out of phase legs. Back elements and limbs are driven by servo motors. We systematically tested the gait patterns with different leg contacts and body undulation provided by geometric mechanics on various environments including flat ground, obstacle course, stair climbing, and unstructured natural terrain. On flat ground, the robot with completely rigid parts moved in the same way as theoretically predicted gaits. As the complexity of the environment increases, adding flexibility into the robot body parts (legs, body joints, etc.) improved the locomotion performance by either reducing the effects of environmental disturbances or increasing stability.