Characterized by their elongate bodies and relatively simple legs, multi-legged robots have the potential to locomote through complex terrains for applications such as search-and-rescue and terrain inspection. Prior work has developed effective and reliable locomotion strategies for multi-legged robots by propagating the two waves of lateral body undulation and leg stepping, which we will refer to as the two-wave template. However, these robots have limited capability to climb over obstacles with sizes comparable to their heights. We hypothesize that such limitations stem from the two-wave template that we used to prescribe the multi-legged locomotion. Seeking effective alternative waves for obstacle-climbing, we designed a five-segment robot with static (non-actuated) legs, where each cable-driven joint has a rotational degree-of-freedom (DoF) in the sagittal plane (vertical wave) and a linear DoF (peristaltic wave). We tested robot locomotion performance on a flat terrain and a rugose terrain. While the benefit of peristalsis on flat-ground locomotion is marginal, the inclusion of a peristaltic wave substantially improves the locomotion performance in rugose terrains: it not only enables obstacle-climbing capabilities with obstacles having a similar height as the robot, but it also significantly improves the traversing capabilities of the robot in such terrains. Our results demonstrate an alternative actuation mechanism for multi-legged robots, paving the way towards all-terrain multi-legged robots.

翻译：多足机器人以其细长躯干和相对简单的腿部结构为特征，在搜救、地形勘测等应用中具备穿越复杂地形的潜力。先前研究通过传播横向躯干波动与腿部步进两种波（下文称为双波模板），已为多足机器人开发出高效可靠的运动策略。然而，这类机器人在攀越高度与其自身尺寸相当的障碍物时能力有限。我们推测此类局限性源于当前用于规划多足运动的双波模板。为探索适用于越障运动的替代波动模式，我们设计了一款具有静态（非驱动）腿的五段式机器人，其每个缆线驱动关节在矢状面（垂直波）具备一个旋转自由度，同时具有一个线性自由度（蠕动波）。我们在平坦地形与崎岖地形上测试了机器人的运动性能。虽然蠕动作用对平坦地面运动的提升有限，但引入蠕动波可显著改善机器人在崎岖地形中的运动表现：它不仅使机器人能够攀越与自身高度相当的障碍物，还大幅提升了机器人在此类地形中的穿越能力。本研究结果展示了一种新型多足机器人驱动机制，为开发全地形多足机器人奠定了基础。