- 學位論文
雙伺服CNC工具機新主從控制方法 之研究與應用
A Study and Application of A New Master-Slave Control Method for Dual-Servo CNC Machine Tools.
摘要
現今工具機為提升切削性能，實現高速的切削進給速度，利用主/從軸伺服系統驅動單一軸向平台成為重要之應用，因此主從伺服同動控制便成為此一應用之關鑑技術。由於現今工具機之控制器及PLC程式運算速度較慢，且控制器為封閉式，無法將較複雜之主從控制方法應用其中，故本研究設計出一簡單型可與現有之CNC控制器結合之新型主從同動控制方法，其可降低同動誤差補償運算時間，快速針對從動軸系統作即時補償修正，以提升主從同動精度。 研究中對單伺服軸採用混合式可變結構控制法則來改善線性馬達伺服落後並抑制外部非線性之干擾，在雙軸同動控制上則結合PLC程式設計採用新型主從同動控制法則，其可對從動伺服軸系統作快速調整控制以降低主動與從動伺服系統間的位置誤差。研究中以龍門式線性馬達平台為實驗對象，經由實機測試證明所提出之控制法則可明顯加快系統響應速度、提升整體平台定位精度，實驗驗證以新型主/從伺服系統所得平台的同動精度較本研究室先前設計之混合式可變結構控制方法平均提升63%，且可使平台達到所設定之加速度 。機台於高負載及高速運動狀態時有慣性現象，會導致機台有過衝及震盪，因此於高速加工時必需以加工精度規劃機台之最大加速度。另外，研究中也於大立公司之線馬工具機進行實驗驗證，經由實機驗證結果分析發現，此機台主/從線性馬達間存在相當大之平行度誤差，此誤差遠大於雙伺服軸間之同動誤差，會嚴重影響雙伺服機台之工作性能，因此二伺服軸間之組裝平行度誤差控制是一重要項目。研究中也發現由於PLC程式具有延遲補償現象，因此若要將此新型主從同動控制法則應用於工具機上，則需更進一步縮短誤差修正執行時間，方能將主從控制發揮到最佳效果。 關鍵字：混合式可變結構控制、新型主從同動控制、同動精度
並列摘要
Abstract Because overshoot and vibration will easily occur to a machine tool due to high acceleration, the maximum acceleration of a machine tool should be designed under the consideration of driving accuracy. In order to enhance the high-speed machining accuracy, the master-slave control becomes the important core technology for a machine tool having a dual-servo system for single axis drive. Since the common used CNC controller is a closed architecture and calculation of control should be fast enough, a new simple master-slave control was designed. In this study, the hybrid variable structure control system (HVSS) was used to resolve the lag and disturbance problem of a linear motor servo system. For bi-linear driving systems, a new master-slave control method in which one driving system is regarded as a reference system and the other driving system is regarded as a following system. Comparing with the previously proposed control method, experimental verification has shown that the acceleration of the system can be improved and the synchronous movement accuracy was improved to 63 percentages. In addition to a linear motor driven platform, verification experiments were also conducted on the linear motor driven machine tool made by DAHLIH Co. The experimental results show that the parallelism error between the two linear motors is a very important design factor for a dual-servo type machine. Besides, because of response delay, PLC program still can not fully satisfy requirement of the synchronous control. Thus, shortening the execution time of control will be the goal of the future study. Key word: hybrid variable structure control system、master-slave control、driving accuracy