Contact Detection and Manipulation With a Shape-Memory Alloy Based Soft Gripper

Soft robotics offers the opportunity to create dexterous machines that can safely handle delicate objects. Grippers made from deformable actuators and compliant materials can deform around the objects with which they come in contact. The continuum mechanics of flexible manipulators can be leveraged for safe manipulation tasks such as twisting and grasping during manufacturing. However, to achieve this goal, contact sensing and controls for manipulators in these soft systems still remain a challenge in the field. This paper demonstrates a shape-memory alloy actuated soft gripper, with each finger able to bend about multiple axes. This enables the soft gripper to perform twisting tasks and handle various and fragile objects. Using capacitive bend sensors, we also demonstrate that the measured impedance of motion can be used as a proxy for contact, greatly increasing performance in a delicate manipulation task