Development of a six-axis force/moment sensor and its control system for an intelligent robot s gripper

Abstract

This paper describes the development of a six-axis force/moment sensor and its control system for an intelligent robot's gripper. An intelligent robot's gripper should detect the forces Fx (x-direction force), Fy and Fz in the gripping direction and in the gravitational direction, and be controlled by the measured forces and the gripper's control system to safely grasp an unknown object. Also, it should detect the moments Mx (x-direction moment), My and Mz to accurately perceive the position of the object in the grippers. Therefore, an intelligent robot's gripper should be composed of a six-axis force/moment sensor which can measure the forces Fx, Fy and Fz, and the moments Mx, My and Mz simultaneously. It is required that each component sensor of the six-axis force/moment sensor generally has the same rated output, and the same capacity (e.g. Fx = Fy = Fz = 50 N, Mx = My = Mz = 5 N m) or different capacity (e.g. Fx = 40 N, Fy = 50 N, Fz = 60 N, Mx = 4 N m, My = 3 N m, Mz = 5 N m) in each force component and moment component in the gripper, depending on the particular application. The control system should have a fast processing speed for measuring the signals of the sensors and controlling the gripper without much delay time, and should be of small size. The grippers are made with a force sensor which can detect force in only one direction. The control system consists of a personal computer and an A/D, D/A converter board.