Self Calibrating Procedure for a 3D Force Observer

In robotic operations where a manipulator is involved, it is well-known that the quantities measured by a wrist force/torque sensor are corrupted by the dynamics of the end effector and manipulator. To solve this problem, an observer, which fuses information from force sensors and accelerometers, was designed recently in order to estimate the contact force exerted by a manipulator to its environment [1]. This paper introduced a high-speed, high-accuracy, versatile, simple, and fully autonomous technique for the calibration of this robotic manipulator 3D force observer by means of active motion. To verify the improvement, an impedance control scheme was used. A dynamic model of the robot-grinding tool using the new sensors was obtained by system identification. The experiments were carried out on an ABB industrial robot with open control system architecture.