Experimental development for thumb-index pinch force measurements during object manipulation with application to robotic hands

Grip force measurement devices are necessary for artificial hands and hand injury rehabilitation. Therefore, methods for measuring applied force in prehension must meet some minimal requirements such as little weight, reliability, feasibility, and low-cost. In this paper, the design of a cost-effective artificial fingertip and a system for recording individual fingertip forces are presented, based on simple force sensing resistors as the main component. The system is able to automatically calibrate the range of forces in the sensors with an acceptable level of accuracy. The system is tested on standard experiments of pinch grip, and its integration into a robotic system is discussed. Moreover, a contact force control using the tactile force sensor as feedback over an anthropomorphic finger is presented.