Abstract
In this paper, we propose dynamic force sensing method for a robot manipulator. A 6-axis wrist force sensor which is commonly used for robot force sensing does not take the direct measurement of the force and moment applied to an end effector externally from the environment of the manipulator, but takes the measurement of the resultant of the gravity, the inertial force and moment on the end effector, and the external force and moment. The separation of the gravitational and inertial force and moment from the measurement of the force sensor is crucial to achieving dynamically accurate force sensing and fast manipulator motion under force feedback control. In this paper, we derive a mathematical model of the force sensing process and formulate the separation of the force and moment as a nonlinear optimal state estimation problem. Then we give an approximate solution to it using extended Kalman filtering techniques. We also show the effectiveness of the method through simulation and experiment for a limited case of manipulator motion.
