Soft and continuum robots present the opportunity for extremely large ranges of motion, which can enable dexterous, adaptive, and multimodal locomotion behaviors. However, as the number of degrees of freedom (DOF) of a robot increases, the number of actuators should also increase to achieve the full actuation potential. This presents a dilemma in mobile soft robot design: physical space and power requirements restrict the number and type of actuators available and may ultimately limit the movement capabilities of soft robots with high-DOF appendages. Restrictions on actuation of continuum appendages ultimately may limit the various movement capabilities of soft robots. In this work, we demonstrate multimodal behaviors in an underwater robot called "Hexapus." A hierarchical actuation design for multiappendage soft robots is presented in which a single high-power motor actuates all appendages for locomotion, while smaller low-power motors augment the shape of each appendage. The flexible appendages are designed to be capable of hyperextension for thrust, and flexion for grasping with a peak pullout force of 32 N. For propulsion, we incorporate an elastic membrane connected across the base of each tentacle, which is stretched slowly by the high-power motor and released rapidly through a slip-gear mechanism. Through this actuation arrangement, Hexapus is capable of underwater locomotion with low cost of transport (COT = 1.44 at 16.5 mm/s) while swimming and a variety of multimodal locomotion behaviors, including swimming, turning, grasping, and crawling, which we demonstrate in experiment.

中文翻译：

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通过分层驱动实现软机器人的多模态运动。

软体和连续机器人提供了极大的运动范围的机会，这可以实现灵巧、自适应和多模式的运动行为。然而，随着机器人自由度 (DOF) 数量的增加，执行器的数量也应该增加，以实现全部驱动潜力。这给移动软机器人设计带来了困境：物理空间和功率要求限制了可用执行器的数量和类型，并可能最终限制具有高自由度附件的软机器人的运动能力。对连续附件驱动的限制最终可能会限制软机器人的各种运动能力。在这项工作中，我们展示了名为“Hexapus”的水下机器人的多模态行为。提出了一种多附肢软机器人的分层驱动设计，其中单个高功率电机驱动所有附肢进行运动，而较小的低功率电机则增强每个附肢的形状。灵活的附肢被设计为能够过度伸展以产生推力，并弯曲以进行抓握，峰值拉力为 32 N。为了推进，我们在每个触手的基部连接了一个弹性膜，该膜通过高速缓慢拉伸。动力电机并通过滑动齿轮机构快速释放。通过这种驱动安排，Hexapus 能够在游泳时以较低的运输成本（COT = 1.44 at 16.5 mm/s）进行水下运动，以及各种多模式运动行为，包括游泳、转身、抓握和爬行，我们在实验。