Dynamic modeling and parameter identification for a gantry-type automated fiber placement machine combined with hydraulic balance system and nonlinear friction

Abstract

A dynamic model considering hydraulic balance system and nonlinear friction is established for a gantry-type automated fiber placement (AFP) machine. To facilitate a comprehensive understanding, the AFP machine is introduced firstly. Due to the vertical movement of large masses, the AFP machine is equipped with a hydraulic balance system, thus a hydraulic model is secondly proposed to reveal the relationship between hydraulic pressure and the movement of the vertical axis. Then, a dynamic equation of the AFP machine is built by the Newton-Euler method, which is subsequently converted into the form of linearized minimum inertia parameters. In addition, the problems of nonlinear friction are also studied, and a segmented friction model is developed. To identify the parameters, issues regarding excitation trajectory, filtering, and identification algorithm are discussed. Corresponding experiments are performed, and the experimental results suggest that the prediction of the dynamic model is highly coincident with measurement data, and their relative error rates are less than 5%, proving the effectiveness of the established model and the identified parameters. Further analysis indicates that the proposed friction model is more in line with the actual situation, and can provide guidance for other friction research.