Design and development of a sensorized cylindrical object for grasping assessment

Aim of this work is to design and develop an instrumented cylindrical object equipped with force sensors, which is able to assess grasping performance of both human and robotic hands. The object is made of two concentric shells between which sixteen piezoresistive sensors have been located in order to measure the forces applied by the hand fingers during grasping. Furthermore, a magneto-inertial unit has been positioned inside the object for acquiring information about object orientation during manipulation. A wireless communication between the electronic boards, responsible for acquiring the data from the sensors, and a remote laptop has been guaranteed. The object has been conceived in such a way to be adopted for evaluating both power and precision grasps and for measuring the forces applied by each finger of the hand. In order to evaluate object performance, a finite element analysis for estimating the deformation of the external shell for different force values has been carried out. Moreover, to evaluate object sensitivity, a static analysis of the force transmitted by the external shell to the underlying sensors has been performed by varying the thickness of the shells. The obtained preliminary results have validated the feasibility of using the developed object for assessing grasping performed by human and robotic hands.