Layer-Jamming Suction Grippers With Variable Stiffness

Abstract

The soft grippers driven by pneumatics have an advantage of effectively lifting soft materials and heavier objects with clean air. They provide multiplanar compliant stability when compared with standard claw-like grippers because of the larger contact area. Such grippers can work on objects with a greater surface area than the gripper itself. However, until now, to enhance the gripping on heavier objects, multiple suction cups are used, which involve tubing and a vacuum pump for each individual cup, which ultimately makes the setup bulky and immovable. Furthermore, using a bigger suction gripper requires bigger tubing and higher negative pressure. To tackle this limitation, we are introducing layer-jamming suction grippers with kirigami pattern for stiffness tuning. The kirigami-patterned base and sheets make a channel from the air tubing to each hole that acts as multiple suction cups. The sheets incorporated within the suction cups, working as layer-jamming, control the stiffness of the prototype. Results highlight that the gripper has the capability of lifting 200 times its own weight with a planar surface and has a strength and durability to withstand a maximum force of 87 N. One important characteristic of the gripper is its adaptability to the curved surfaces, which has an enhanced grasp and is able to lift 154 times its own weight. The ease of fabrication, low cost, and higher lifting capabilities open up a wide area of opportunities to see the advancements in technologies with the suction grippers.