Improving Industrial Grippers With Adhesion-Controlled Friction

Effective handling of delicate objects remains a challenging problem in manufacturing. Instead of using a specialized gripper or control scheme, we present a solution involving gecko-inspired directional adhesives affixed to an industrial robot gripper and tactile sensor. The adhesives sustain large shear forces with very low pressure. They also release objects without residual adhesion when the grip is relaxed. It is desirable to predict the maximum forces and moments the gripper can exert without slipping. For this purpose the tactile sensor provides an estimate of the area of contact, and a force/torque sensor measures the overall force and moment. To resist forces and moments in multiple directions, it is best if the directional adhesives do not all have a single orientation. A chevron pattern strikes a good balance between performance and ease of fabrication.