Thesis Topic

Real-time compensation of geometric errors on 5-axis machine tool by acting on the position control loop
Compensation active par action sur la rétroaction d’asservissement en position sur machine-outil 5 axes : application à la correction géométrique de la structure

Abstract

High accurate machining requires error compensation. Among thermally, cutting forces, tool wear, actuators or sensors induced errors, kinematic errors due to geometric inaccuracies has the biggest impact on the final accuracy of the machined part. Furthermore, the addition of rotary axes to linear motion ones in 5 axis CNC machines increases the complexity of performing an accurate position and orientation of the tool. Either mechanical-based or software-based compensation techniques have already been tested in the past. Nevertheless, these last require modification of the post-processor, or of the code or parameters of the NC.

After the establishment of a geometric model of the structural loop based on full-rigid multibody assumption, and an identification process by using in situ measurement, the CAPTURES project aims developing a real-time compensation methodology. Its main objective is to enhance the accuracy of the machine tool, in all its workspace. It will take place in each axis position control feedback loop, in which rotary or linear encoder’s signals will be compensated and sent to the controller. They’re generated thanks to the real position measurement of all the axes and the previously identified geometric model. The CAPTURES block (i.e. embedded controlling system) will have to fit perfectly in the control command chain.

Doctoral advisors

• Guillaume FROMENTIN -Director,
• Fabien VIPREY,
• Charly EUZENAT.

Partner

• CETIM

Project

PhD in the frame of the CAPTURES project

Funding

• CDSN (contrats doctoraux spécifiques aux normaliens)

Start

1st of September 2022

Expected end

1st of September 2025