Shape-induced obstacle attraction and repulsion during dynamic locomotion

Abstract

Robots still struggle to dynamically traverse complex 3-D terrain with many large obstacles, an ability required for many critical applications. Body-obstacle interaction is often inevitable and induces perturbation and uncertainty in motion that challenges closed-form dynamic modeling. Here, inspired by recent discovery of a terradynamic streamlined shape, we studied how two body shapes interacting with obstacles affect turning and pitching motions of an open-loop multi-legged robot and cockroaches during dynamic locomotion. With a common cuboidal body, the robot was attracted towards obstacles, resulting in pitching up and flipping-over. By contrast, with an elliptical body, the robot was repelled by obstacles and readily traversed. The animal displayed qualitatively similar turning and pitching motions induced by these two body shapes. However, unlike the cuboidal robot, the cuboidal animal was capable of escaping obstacle attraction and subsequent high pitching and flipping over, which inspired us to develop an empirical pitch-and-turn strategy for cuboidal robots. Considering the similarity of our self-propelled body-obstacle interaction with part-feeder interaction in robotic part manipulation, we developed a quasi-static potential energy landscape model to explain the dependence of dynamic locomotion on body shape. Our experimental and modeling results also demonstrated that obstacle attraction or repulsion is an inherent property of locomotor body shape and insensitive to obstacle geometry and size. Our study expanded the concept and usefulness of terradynamic shapes for passive control of robot locomotion to traverse large obstacles using physical interaction. Our study is also a step in establishing an energy landscape approach to locomotor transitions.

References in corpus (10)

• A Terradynamics of Legged Locomotion on Granular Media
• Sensitive dependence of the motion of a legged robot on granular media
• Terradynamically streamlined shapes in animals and robots enhances traversability through densely cluttered terrain
• Body-terrain interaction affects large bump traversal of insects and legged robots
• An energy landscape approach to locomotor transitions in complex 3D terrain
• Cockroaches use diverse strategies to self-right on the ground
• Dynamic traversal of large gaps by insects and legged robots reveals a template
• Mechanical principles of dynamic terrestrial self-righting using wings
• Snakes partition their body to traverse large steps stably
• Coordinated appendages accumulate more energy to self-right on the ground

Cited by in corpus (6)

• The need for and feasibility of alternative ground robots to traverse sandy and rocky extraterrestrial terrain
• Omni-Roach: A legged robot capable of traversing multiple types of large obstacles and self-righting
• Cockroaches adjust body and appendages to traverse cluttered large obstacles
• Snakes combine vertical and lateral bending to traverse uneven terrain
• A minimalistic stochastic dynamics model of cluttered obstacle traversal
• Environmental force sensing helps robots traverse cluttered large obstacles using physical interaction