Estimation of Robot Dynamics Parameters: Theory and Application

This paper presents an algorithm for estimating the dynamics parameters of an N degrees-of-freedom robotic manipulator. In our previous work [8] it was shown that the Newton-Euler model model which is nonlinear in the dynamic parameters can be transformed into an equivalent modified model which is linear in dynamic parameters. To introduce our identification algorithm, we cast this modified Newton-Euler model in a form wherein the joint torques/forces are expressed as a product of a matrix and a vector of dynamics parameters. The elements of this matrix are a function of the joint variables and the kinematic parameters only. The dynamics parameters are then estimated from this linear (in dynamics parameters) formulation using the least squares estimation method. We have implemented our algorithm and the results of this experimental implementation to estimate the dynamics parameters of the six degrees-of-freedom CMU DD Arm 11 are presented. The estimated dynamics parameters have also been used to evaluate the effect of dynamics compensation in model-based manipulator control methods.