Origami-Based Decoupling Clutch Achieves Energy-Efficient Legged Robots

Legged robots are capable of achieving energy-efficiency by introducing elastic elements in parallel with the actuators during the stance phase. However, the parallel elastic actuation results in a coupling motion between the parallel spring and the flexion movement of the leg mechanism during the swing phase. This coupling hinders the dexterity of joint movement and increases energy consumption which degrades the energy-efficiency of legged robots. In this letter, we present an origami-based decoupling clutch for energy-efficient legged robots. The decoupling mechanism is realized by a Kresling-based clutch that switches the connection between the parallel spring and the robotic leg without additional control effort. During stance, the parallel spring and the leg are engaged to reduce the torque requirements. Furthermore, the leg can achieve unobstructed movement when the spring is disengaged during the swing phase. Subsequently, we design a single-leg prototype to validate the enhancement of energy-efficiency. Experimental results demonstrate that the robot with the proposed origami-based decoupling clutch can reduce the required knee flexion torque and energy consumption by 37.6% and 31%, respectively, of what is required for the robot without the clutch.