An untethered soft robotic gripper with high payload-to-weight ratio

Abstract Most of the soft grippers with high payload cannot carry cumbersome control systems and power sources themselves, and have to be tethered to external hardware through tubes and wires. To tackle this problem, we proposed an untethered soft pneumatic gripper with a high payload by developing a soft gripping structure with a high gripping force to pressure ratio. The untethered soft gripper integrates silicone elastomer structure, pneumatic artificial muscle (PAM), air pump, battery, controller, solenoid valve, and other components, with a total weight of 1.5 kg. The entire power sources of the untethered soft gripper are supplied by a battery, allowing it to perform at least 300 opening and closing movements. The lightweight and high load capacity of the untethered soft gripper enable its payload to weight ratio to exceed 26. Further, the untethered soft gripper can be installed on an unmanned aerial vehicle to expand its workspace. Also, a tightening force model for winding PAMs is presented in this paper, which can be used to evaluate the pressing force of the untethered soft gripper on the surface of an object.