Study And Development On Open-Architecture CNC System

The industry and national economy of developed country is based on the mechanical manufacturing. The mechanical manufacturing is based on the computer numerical control machine(NC). NC is the result of information technology and traditional machine and it is the base of advanced manufacturing. In order to meet the request of modern manufacturing user, the structure of CNC is making great change. The open architecture CNC is substituting traditional CNC by degrees for its distinct excellence.Along with the fast development of information technology, open architecture CNC system has been entering upon a new phase, which is all-software CNC, software CNC or soft CNC. Software CNC means that all the functions of CNC system, such as interpolation, position control and PLC, are implemented with software modules. The flexibility of software makes it available for CNC systems to achieve higher-level openness. "PC-based" is a practical and definite way to actualize the openness of CNC systems at present. The CNC system developed in this paper adopts the model of "universal PC + connecting board" . The PC takes on not only system's management, which is non-real-time mission, but also real-time missions including real-time interpolation, position controlling, system state inspecting and machining state simulating. The connecting board takes on the responsibility to connect PC port and CNC machine drive. This model gives user much agility. It makes great use of PC software and hardware resource, and the cost is low. Thus the all-software CNC is suit of future advanced manufacturing technique's requirement.Chapter one discusses the definition, system structure and realization form of open architecture CNC system which has the best future. Chapter two primary studies and digests a new NC programming data interface international standard, ISO 14649 (Standard for the Exchange of product Model Data, STEP-NC), which is being researched and made in international scope. The aim of this standard is to provide a neutral mechanism which doesn't rely on concrete system, uniform data model which is able to describe the product's whole life cycle, consequentlyrealizes the product information's standard of whole manufacturing process even every industry field. Chapter three to Chapter five is the key and core of this thesis. Chapter three analyses the open architecture system's system structure and demand, builds CNC system's whole structure model according to open architecture design principle, establishes CNC system software structure model applying soft chip thinking. Chapter four discusses the developing environment and developing method choosing, software structure building, data stream analyzing, soft chips of machining code translating and interpolation, and introduces the multi-task attempering strategy under Windows operation system. Chapter five introduces the CNC software's function components and system's workflow. In the last, Chapter six summarizes the contents of this thesis and indicates the direction to continue this study.