Mirror milling trajectory planning for large thin-walled parts based on Fuzzy-ADRC controlled force pre-supporting

Abstract

Reliable supporting with pre-defined force is essential for mirror milling to solve the problem of efficient and stable machining of large thin-walled parts. However, it is difficult to control the support force by traditional coordinate offset or static pressure fluctuation to ensure machining stability and residual wall thickness accuracy at the same time. In this paper, a novel mirror milling trajectory planning method based on controlled force pre-supporting is proposed. Firstly, the supporting trajectory is updated by means of pre-supporting with pre-defined supporting force. And a supporting force controller based on fuzzy active disturbance rejection control (ADRC) is designed. Secondly, taking the new supporting trajectory as basis, the mirror machining trajectory is planned considering the mirror constrains and the residual wall thickness. Finally, the control process of supporting force was simulated and the mirror machining experiments were carried out. Compared with the real-time supporting mode and the Fuzzy-PID-based pre-supporting mode, the Fuzzy-ADRC-based pre-supporting mode can obtain higher wall thickness accuracy and surface quality.