Position geometric error modeling, identification and compensation for large 5-axis machining center prototype

• A geometric error model is established for large 5-axis machining center prototype.
• A virtual rigid-body method is put forward for calculating positioning error of each large translational axis
• Analytical models based on least-squares theory are adopted to compute error values at an arbitrary position.
• Recursive software-based error compensation method is used to compensate the position geometric errors.
• Position accuracy of large machining center prototype has been improved with compensation and up to the design requirements.

This paper presents a position geometric error modeling, identification and compensation method for large 5-axis machining center prototype. First, regarding the prototype as a rigid multi-body system, a geometric error model has been established, which supports the identification of position geometric error associated with a translational axis by using laser interferometer, and a rotational axis by using laser tracker. Second, based on this model, an improved identification approach named as virtual rigid-body is put forward for calculating positioning error of each large translational axis. Detailed derivation of a generalized matrix equation is given. Third, analytical models based on the least-squares theory were adopted to compute error values at an arbitrary position for error compensation. Finally, the identified position geometric errors were compensated by using recursive software-based error compensation method. The results show that the position accuracy of large machining center prototype has been improved with compensation and up to the design requirements.