Research On Technology Of Building Open CNC System With Intelligent Characteristic

In the field of modern manufacturing, promotion of manufacturing technology is significantly encouraged by the wide application of CNC system. With the increase of market requirements and the development of relevant supporting technologies, CNC system is now undergoing a technological innovation that is characterized mostly by openness and functional composition, which will certainly result in the innovation of structure and control strategy of the CNC system. According to this situation, this dissertation makes deep research on open architecture, structure modeling, dynamic analysis and intelligent strategy.Based on the comprehensive planning of function module of CNC system, a four-layer open architecture reference model is proposed. A hierarchical chain-typed registration strategy of function module is given, and the definition of registration unit structure is presented. With this strategy, local structure of the CNC system can be adjusted. User-defined configuration of specialized technology can be archived by the presentation of function component. Further analysis shows that the reference model supports three deferent degrees of system configuration.A modeling strategy of the CNC system based on object-orient technology is proposed, and a standard modeling flow is discussed. On the basis of deep research on use-case of the system, a class diagram model of the kernel use-case package, in other words, the motion control package of the system is built. Behavior of each class is discussed, on the basis of which, a sequence diagram of channel servo-control system under auto-mode is built, and a state machine diagram is presented. Finally, operation logic of the system is analyzed with an activity diagram.Net theory is introduced to the analysis of dynamic performance of the CNC system. A decision place is defined to get rid of conflicts caused by the imperfection of extension of environment information. With this definition, simulation is carried out to verify the general structure of the system. Analysis method based on formalized mathematics is introduced to analyze DNC process. An equal transformation of timed transition Petri net with inhibitor arc is proposed to descend its dimension and to decrease analyzing difficulty. On the basis of this, a simulation example is carried out and a strategy of structure adjusting is given according to analysis conclusions. Further simulation illustrates the effect of the adjustment. Theory of colored Petri net is introduced to condense the Petri net model of multi-axis servo control progress. Analysis shows that with this technology, the system's Petri net models with similar structure units can be simplified effectively.By discussing the influencing range of intelligent strategy and control target of each stage of machining cycle, a runtime intelligent strategy based on information classification is proposed. Adaptive GA is introduced to find optimization cutting parameters at the earlier stage of machining cycle. A fuzzy adaptive machining control strategy based on the synthetic monitoring on current and voltage of spindle motor is put forward, and the relevant control model is given. On the basis of that fuzzy control model, RBF neural network is introduced to build a simulation model of the adaptive control system. Simulation analysis proves that the fuzzy adaptive control system is able to realize intelligent control of NC machining with higher identification as well as control precision.A CNC system prototype with five-axis simultaneous control power is developed based on the foregoing research achievements, and is integrated to a five-axis machining center, which presents a preliminary practical verification of relevant theoretical achievements.