Design and Fabrication of a Soft Robotic Hand and Arm System

We present the hardware design and fabrication of a soft arm and hand for physical human-robot interaction.

The six DOF arm has two air-filled force sensing modules which passively absorb impact and provide contact force feedback. The arm has an inflated outer cover which encloses the arm’s underlying mechanisms and force sensing modules. An internal projector projects a display on the inside of the cover which is visible from the outside. On the end of the arm is a 3D printed hand with air-filled, force sensing fingertips. We validate the efficacy of the outer cover design by bending the arm to reach out and grasp an object. The outer cover performs as intended, providing enough volume and range of motion for the arm to move, and stretching at the elastic relief features in the cover. We also validate the hand design by implementing a grasping algorithm in which the fingers follow a closing trajectory, make contact, then maintain a given range of fingertip pressure. Using this algorithm, the hand is able to gently grasp a soft object.