Towards an Insect Inspired Segmented Robot Leg for Passive Deflection Over Steps

When observing insects walking over uneven terrain, we often see legs colliding with ground obstacles but quickly recovering by deflecting over these obstacles. Previous work has observed this behavior in both cockroaches and ants in both laboratory and natural settings. Given the rapid speed of locomotion and observations of quick leg recovery, it is hypothesized that foot-object interactions may be primarily aided by passive mechanical properties rather than through reactive control. These observations from nature have inspired our research into legged robotic solutions that can mimic insects by passively deflecting over obstacles encountered in the swing phase. Inspired by the multi-segmented architecture of insect legs, we have developed a 3D printed segmented robot leg that allows a walking robot to passively deflect over obstacles in the swing phase and bear weight during the stance phase. We performed walking tests over laboratory models of uneven terrain such as vertical steps and we observe that segmented multi-stiffness legs aid in successful walking. This result offers new design choices for dynamically stable walking robots over natural terrain.