Estimation of Inertial Parameters of Rigid Body Links of Manipulators

Abstract

A method of estimating the mass, the location of center of mass, and the moments of inertia of each rigid body link of a robot during general manipulator movement is presented. The algorithm is derived from the Newton-Euler equations, and uses measurements of the joint torques as well as the measurement and calculation of the kinematics of the manipulator while it is moving. The identification equations are linear in the desired unknown parameters, and a modified least squares algorithm is used to obtain estimates of these parameters. Some of the parameters, however, are not identifiable due to restricted motion of proximal links and the lack of full force/torque sensing. The algorithm was implemented on the MIT Serial Link Direct Drive Arm. A good match was obtained between joint torques predicted from the estimated parameters and the joint torques computed from motor currents.