以EtherCAT實現CNC先進伺服運動控制設計之關鍵技術

Abstract

網路控制系統透過運算、網路通訊、控制單元整合，網路控制系統可以簡化人員的遠端管理與建立，進而提升系統性能與便利。因此，建立乙太網路自動化技術EtherCAT(Ethernet for control automation technology)通訊介面，整合EtherCAT網路通訊與伺服馬達控制，以利遠端下達控制命令與設計控制器。本論文在EtherCAT主站 ET9200透過Beckoff ET2000封包監測器分析封包壅塞與遺失，並提出交錯發送與接收通訊與資料遺失估測器來改善資料遺失。另外，工研院已開發出一套以INtime即時環境之EtherCAT網路化CNC控制介面。INtime的取樣時間可達0.25ms，而且透過ET2000封包監測器量測封包傳輸時間，並求得標準差，判斷出INtime即時性佳，並可直接對CNC車床XZ平台做運動控制。最後，為了追求高精度雙軸控制，整合比例-微分控制(PD)、數位擾動觀測器(DDOB) 以及使用交叉耦合控制(CCC)，本研究有效的彈性實現不同先進控制器設計在EtherCAT之CNC控制器上，有效的改善了CNC的運動精密度。此外，進一步在EtherCAT的CNC控制器上，實現了靜態非線性摩擦力NFC補償器，以及動態非線性摩擦力LuGre補償器，CNC平台循圓指令經過由馬達解碼器測試，在比較P控制器與現有之整合控制器，原有的真圓度17.8 um有效的改善至3.8 um，而由DBB測試之真圓度也由原有之26.2 um改善至現有的12.0 um，凸顯EtherCAT適合於實現彈性的CNC控制架構與補償器。

Ethernet Automation Technology EtherCAT (Ethernet for control automation technology) that is established for real-time control applications now is widely adopted in Industrial automation. In this thesis, the packet congestion and data dropout in EtherCAT master ET9200 were analyzed by the packet monitor of Beckoff ET2000. Both the interleaving transmission/receive communication and the missing message estimator are proposed to improve the data loss. On the other hand, ITRI has developed an CNC control interface with the real-time EtherCAT system INtime for master of EtherCAT Internet communication, experimental results that Beckoff ET2000 measure packet transmission time indicate that the sampling time can be set to 0.25ms without data dropout. By implementing the EtherCAT CNC interface on the Tongtai CNC XZ table, all the proportional-derivative (PD) controller, the digital disturbance observer (DDOB), and the cross-coupled controller (CCC) can be realized. Furthermore, both the static nonlinear friction compensator (NFC) and the dynamic nonlinear friction compensator LuGre model were realized on the real-time EtherCAT CNC controller to significantly improve motion precision. Compared with the P Controller, the roundness was improved from 17.8 to 3.8 based on the encoder measurements by applying the proposed integrated controller. Furthermore, its roundness was also significantly reduced from 26.2 to 12.0 from the measurements of double-ball bar.