A Low-Cost Force Measurement Solution Applicable for Robotic Grippers

Industrial robots find profound usage in today’s industries and an important characteristic required of such robots in pick-and-place operations is determining the gripping force when picking objects. This paper presents the use of a FlexiForce force sensor for measuring the gripping force when picking work-pieces using the two-finger gripper of a pick-and-place robot. This thin and flexible analogue force sensor is capable of measuring both static and dynamic forces. It has an output resistance that is inversely proportional to the applied force and easily calibrated and interfaced to a microcontroller with an in-built analogue-to-digital convertor. Through experimentation, a relationship between the weight of work-piece to be gripped and the force to be applied for gripping was determined. This was used to successfully manipulate work-pieces of various shapes and sizes up to the robot payload of 0.5 kg. Analysis of various forces acting on the work-piece was also carried out.