Robots still struggle to dynamically traverse complex 3D 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 expands 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.

机器人仍然难以动态穿越具有许多大障碍的复杂3D地形，这是许多关键应用程序所需的能力。身体与障碍物之间的相互作用通常是不可避免的，并且会引起运动中的扰动和不确定性，从而挑战封闭形式的动态建模。在这里，受最近发现的地形动力学流线型形状的启发，我们研究了与障碍物相互作用的两个身体形状如何在动态运动过程中影响开环多腿机器人和蟑螂的转动和俯仰运动。机器人使用一个普通的长方体，被吸引到障碍物上，导致俯仰和翻转。相反，在椭圆形的身体中，机器人会被障碍物击退，并易于穿越。该动物显示出由这两个身体形状引起的定性相似的转弯和俯仰运动。然而，与长方体机器人不同，长方体动物能够逃避障碍物的吸引并随后高俯仰和翻转，这启发了我们为长方体机器人开发经验性的俯仰转弯策略。考虑到我们在机器人零件操纵中自我推进的身体－障碍物交互作用与零件－进料器交互作用的相似性，我们开发了准静态势能景观模型来解释动态运动对身体形状的依赖性。我们的实验和建模结果还表明，障碍物的吸引或排斥是运动身体形状的固有属性，并且对障碍物的几何形状和大小不敏感。我们的研究扩展了地形动力学形状的概念和实用性，从而可以被动地控制机器人的运动以使用物理交互作用来穿越较大的障碍物。