Multi-legged locomotor transitions in complex 3-D terrain

To traverse complex 3-D terrain with obstacles as large as themselves, animals and robots must transition across different modes. However, most mechanistic understanding of terrestrial locomotion concerns how to generate and stabilize near-steady-state, single-mode locomotion (e.g., walk, run). We know little about how to use physical interaction to make robust locomotor transitions. Here, we review our progress towards filling this gap. We studied several simplified model systems representing diverse challenges for multi-legged locomotion in complex 3-D terrain and modelled locomotor-terrain interaction using a potential energy landscape approach. Across model systems, locomotor transitions are stochastic, destabilizing, barrier-crossing transitions on the landscape. They can be induced by feed-forward self-propulsion and are facilitated by feedback-controlled active adjustment. General physical principles and strategies from our systematic studies already advanced robot performance in simple model systems. Efforts remain to better understand the intelligence aspect of locomotor transitions and how to compose larger-scale potential energy landscapes of complex 3-D terrain from simple landscapes of abstracted challenges.

Dr. Chen Li