Title: Slack-based tunable damping leads to a trade-off between robustness and efficiency in legged locomotion Show Chinese title

Title: 基于松驰的可调阻尼在腿部运动中导致鲁棒性与效率之间的权衡

Abstract: Animals run robustly in diverse terrain. This locomotion robustness is puzzling because axon conduction velocity is limited to a few ten meters per second. If reflex loops deliver sensory information with significant delays, one would expect a destabilizing effect on sensorimotor control. Hence, an alternative explanation describes a hierarchical structure of low-level adaptive mechanics and high-level sensorimotor control to help mitigate the effects of transmission delays. Motivated by the concept of an adaptive mechanism triggering an immediate response, we developed a tunable physical damper system. Our mechanism combines a tendon with adjustable slackness connected to a physical damper. The slack damper allows adjustment of damping force, onset timing, effective stroke, and energy dissipation. We characterize the slack damper mechanism mounted to a legged robot controlled in open-loop mode. The robot hops vertically and planar over varying terrains and perturbations. During forward hopping, slack-based damping improves faster perturbation recovery (up to 170%) at higher energetic cost (27%). The tunable slack mechanism auto-engages the damper during perturbations, leading to a perturbation-trigger damping, improving robustness at minimum energetic cost. With the results from the slack damper mechanism, we propose a new functional interpretation of animals' redundant muscle tendons as tunable dampers. Show Chinese abstract

Abstract: 动物在各种地形上都能稳健地奔跑。 这种运动的稳健性令人困惑，因为轴突传导速度仅限于每秒几米。 如果反射回路传递感觉信息存在显著延迟，人们会预期这会对感觉运动控制产生不稳定影响。 因此，另一种解释描述了一种低层次自适应机械结构和高层次感觉运动控制的分层结构，以帮助缓解传输延迟的影响。 受自适应机制触发即时反应的概念启发，我们开发了一个可调节的物理阻尼系统。 我们的机制结合了一条具有可调松紧度的肌腱和一个物理阻尼器。 松紧阻尼器允许调整阻尼力、启动时间、有效行程和能量耗散。 我们对安装在开环模式下控制的腿式机器人上的松紧阻尼机制进行了表征。 机器人在不同地形和扰动下进行垂直和平面跳跃。 在向前跳跃过程中，基于松紧的阻尼在更高的能量消耗（27%）下提高了扰动恢复速度（最多170%）。 可调节的松紧机制在扰动期间自动激活阻尼器，导致扰动触发的阻尼，从而在最小的能量消耗下提高稳健性。 根据松紧阻尼机制的结果，我们提出了一种新的功能解释，即动物的冗余肌肉肌腱作为可调节阻尼器。