Self-locking mechanism for variable stiffness rigid–soft gripper

Research paper by Xin-Yu Guo, Wen-Bo Li, Qiu-Hua Gao, Han Yan, Yan-Qiong Fei Wen-Ming Zhang

Indexed on: 18 Feb '20Published on: 14 Feb '20Published in: Smart materials & structures


Pneumatic soft grippers made of silicone have been successfully applied in the industrial field of grabbing fragile objects. But their inherent low stiffness often limits the practical application in scenarios required high stiffness or large load capacity. To expand the application of soft grippers, a self-locking mechanism realized by an exoskeleton structure is proposed in this work. The stiffness, load carrying capacity, and grabbing stability of this soft–rigid grippers can be enhanced in the premise of maintaining sufficient compliance. The resulted rigid–soft gripper has the ability of tuning its stiffness, simply by locking and unlocking the ratchet-and-pawl of the exoskeleton structure. The locking process is automatically implemented with the bending deformation of soft gripper, and the unlocking process is realized quickly by a simple pneumatic unlocking actuator. The stiffness, grasping motion and output force of the gripper are experimentally characterized theoretic...