Design of new Sensory Soft Hand: Combining air-pump actuation with superimposed curvature and pressure sensors

This paper presents the design of a new sensory soft hand that can be adapted to the wrists of small humanoids like the NAO robot. The fingers of the hand can act as a gripper thanks to air pump actuation. The innovation resides in the internal face of each finger which is equipped with a superimposition of four piezo resistive sensors and one curvature sensor. Thanks to this multi-layered arrangement of sensors, it is possible to estimate the curved shape of the fingers and the amount of pressure that is exerted by the object grasped by the hand. The combination of forces and deformation measurements resulting from the interaction of the gripper with external objects is essential for the quality of the grasp, and even allows to estimate properties of the object. In addition to usual advantages of soft grippers like mechanical compliance, shock resistance, and lightweight, this gripper is simple to manufacture, low cost and easy to fit.