Nonlinear modelling and identification of a high precision laser tracking system

In this paper, the nonlinear modeling and identification of a high precision laser tracking system is presented. In the first part of this study, the authors introduce the experimental set-up as well as the dynamic modeling of the laser tracker system. The derived nonlinear model represents the whole light path of the laser beam, which includes the utilized laser interferometer, the beam deflecting unit as well as the motion of the tracked tool center point. In the second part of this contribution, the parameter identification and the model validation process based on experimental data is presented. Afterwards the authors design a model based MIMO controller, which enables the possibility to decouple the interactive variables. At the end, the effectiveness of the proposed control approach is shown by simulation.