Identification of the dynamic parameters of the Orthoglide

This paper presents the experimental identification of the dynamic parameters of the Orthoglide, a 3-DOF parallel mechanism. The dynamic identification model is based on the inverse dynamic model, which is linear in the parameters. The model is computed in a closed form in terms of the Cartesian dynamic model elements of the legs and of the Newton-Euler equation of the platform. The base inertial parameters of the robot, which constitute the identifiable parameters, are given.

1 Introduction

The inverse dynamic model is important for high performance control algorithms, and the forward dynamic model is required for their simulation. For these two applications the numerical values of the dynamic parameters (inertial and friction) must be known. The determination of the base inertial parameters, which represent the only identifiable parameters [2], is treated in this paper by a numerical method [3]. This method is based on the QR decomposition of the observation matrix of the dynamic identification model of the robot. The experimental identification of the dynamic parameters is based on the use of a dynamic model linear in the parameters. This model permits to use the least squares solution to solve the estimation problem [4].