A Novel, Variable Stiffness Robotic Gripper Based on Integrated Soft Actuating and Particle Jamming

This article presents the design principle and fabrication of a variable stiffness soft robotic gripper for adaptive grasping and robust holding. The proposed robotic gripper is based on a finger design that combines a fiber-reinforced soft actuator and a particle pack. The soft actuator is responsible for the bending motion of the finger, and the particle pack acts as a stiffness-changeable interface between the finger and the object. In the natural state, the particle pack is soft and adaptive to part geometry. It can rapidly stiffen (through vacuum) to resist external load or to freeze the currently bent contour of the finger. Experimental studies have shown that more than a 10-fold stiffness enhancement is achievable. Therefore, the proposed gripper is capable of handling objects with different shapes, weights, and rigidities, which have been a great challenge for robotic grasping. For more effective grasping, a grasping strategy is designed for the proposed soft gripper with simultaneous consideration of grasping adaption and robustness.