Institute of AI and Robotics, State Key Laboratory of Medical Neurobiology, MOE Engineering Research Center of AI & Robotics, Fudan University, Shanghai, 200433, China.
Adv Sci (Weinh). 2023 May;10(14):e2206336. doi: 10.1002/advs.202206336. Epub 2023 Feb 12.
Annelids such as earthworms are considered to have central pattern generators (CPGs) that generate rhythms in neural circuits to coordinate the deformation of body segments for effective locomotion. At present, the states of earthworm-like robot segments are often assigned holistically and artificially by mimicking the earthworms' retrograde peristalsis wave, which is unable to adapt their gaits for variable environments and tasks. This motivates the authors to extend the bioinspired research from morphology to neurobiology by mimicking the CPG to build a versatile framework for spontaneous motion control. Here, the spatiotemporal dynamics is exploited from the coupled Hopf oscillators to not only unify the two existing gait generators for restoring temporal-symmetric phase-coordinated gaits and discrete gaits but also generate novel temporal-asymmetric phase-coordinated gaits. Theoretical and experimental tests consistently confirm that the introduction of temporal asymmetry improves the robot's locomotion performance. The CPG-based controller also enables seamless online switching of locomotion gaits to avoid abrupt changes, sharp stops, and starts, thus improving the robot's adaptability in variable working scenarios.
环节动物（如蚯蚓）被认为具有中央模式生成器（CPG），它们在神经回路中产生节律，以协调身体节段的变形，从而实现有效的运动。目前，通常通过模仿蚯蚓的逆行蠕动波来整体地和人为地分配蚯蚓状机器人节段的状态，这种方法无法适应可变环境和任务的步态。这促使研究人员通过模仿 CPG 将生物启发式研究从形态学扩展到神经生物学，从而构建一个用于自主运动控制的通用框架。在这里，利用耦合的 Hopf 振荡器的时空动力学不仅统一了两种现有的步态生成器，以恢复时间对称相位协调步态和离散步态，而且还产生了新的时间不对称相位协调步态。理论和实验测试一致证实，引入时间不对称性可以提高机器人的运动性能。基于 CPG 的控制器还可以实现运动步态的无缝在线切换，以避免突然的变化、急剧的停止和启动，从而提高机器人在不同工作场景中的适应性。
