This paper presents a new and simple procedure to identify link mass parameters used for gravity compensation and on-line automatic torque sensor calibration for a robot manipulator. The approach employs single-joint rotation and a recursive procedure that proceeds distally to proximally to identify composite mass moments. Experimental results on presented for the Sarcos Dextrous Arm.

This paper presents an autonomous method to calibrate joint torque sensors for advanced robots; as a by-product, the position sensors can also be calibrated. When one joint of a manipulator is rotated the gravity torque exerted on the joint varies sinusoidally with rotation angle. By means of sinusoidally curve fitting, the bias of the torque sensor and the gain of the position sensor can be found directly. The gravity vector expressed in the defined base coordinates, can also be found. We then determine the torque sensor gain as well as the rotation angle offset, by attaching a known load to robot in different end positions. Experimental results are shown for the first two joints of the Sarcos dextrous arm.>

Describes the use of a nonlinear proportional and derivative (NPD) controller for both non-contact transition force control (NCTFC) (zero velocity when contact occurs) and contact transition force control (CTFC) (non-zero velocity when contact occurs). The authors present a gain design method for NCTFC. Simulations and experiments on the Sarcos Dextrous Arm show that PD control becomes unstable for CTFC while NPD control is stable and reaches the steady state quickly. Experiments with human subjects on NCTFC and CTFC are also presented.>