Department of Mechanical Engineering, University of California, San Diego, La Jolla, CA 92093, USA.
Materials Science and Engineering Program, University of California, San Diego, La Jolla, CA 92093, USA.
Sci Robot. 2021 Feb 17;6(51). doi: 10.1126/scirobotics.aay2627.
Pneumatically actuated soft robots have recently shown promise for their ability to adapt to their environment. Previously, these robots have been controlled with electromechanical components, such as valves and pumps, that are typically bulky and expensive. Here, we present an approach for controlling the gaits of soft-legged robots using simple pneumatic circuits without any electronic components. This approach produces locomotive gaits using ring oscillators composed of soft valves that generate oscillating signals analogous to biological central pattern generator neural circuits, which are acted upon by pneumatic logic components in response to sensor inputs. Our robot requires only a constant source of pressurized air to power both control and actuation systems. We demonstrate this approach by designing pneumatic control circuits to generate walking gaits for a soft-legged quadruped with three degrees of freedom per leg and to switch between gaits to control the direction of locomotion. In experiments, we controlled a basic walking gait using only three pneumatic memory elements (valves). With two oscillator circuits (seven valves), we were able to improve locomotion speed by 270%. Furthermore, with a pneumatic memory element we designed to mimic a double-pole double-throw switch, we demonstrated a control circuit that allowed the robot to select between gaits for omnidirectional locomotion and to respond to sensor input. This work represents a step toward fully autonomous, electronics-free walking robots for applications including low-cost robotics for entertainment and systems for operation in environments where electronics may not be suitable.
气动驱动的软体机器人因其适应环境的能力而备受关注。在此之前，这些机器人一直使用机电组件（如阀门和泵）进行控制，而这些组件通常体积庞大且昂贵。在这里，我们提出了一种使用简单的气动回路控制软腿机器人步态的方法，而无需任何电子元件。该方法使用由软阀组成的环形振荡器产生类似于生物中央模式发生器神经电路的振荡信号，气动逻辑元件根据传感器输入对这些信号做出反应，从而产生运动步态。我们的机器人只需要一个恒定的压力气源即可为控制和致动系统提供动力。我们通过设计气动控制回路来为每条腿具有三个自由度的四足软体机器人生成步行步态，并在步态之间切换以控制运动方向，从而证明了这种方法。在实验中，我们仅使用三个气动记忆元件（阀门）来控制基本的步行步态。使用两个振荡器电路（七个阀门），我们能够将运动速度提高 270%。此外，我们设计了一个气动记忆元件来模拟双刀双掷开关，展示了一种控制电路，使机器人能够在步态之间进行选择以实现全方位运动，并对传感器输入做出响应。这项工作代表了朝着完全自主、无需电子设备的步行机器人迈出的一步，适用于包括娱乐用低成本机器人和在不适合使用电子设备的环境中运行的系统等应用。
