Design And Implementation Of Reconfigurable Control Kernel In Open CNC System

Nowadays, the researches of CNC system include the following aspects: Open CNC system, network based CNC system and intelligent CNC system. Being one of them, open CNC is one important research field.Depending on the openness of CNC system, open CNC systems can be divided into three classes: Open MMC, kernel with restricted openness, open control kernel system.The kernel talked above means a software module that accomplish the gaven task with required function and quality of control system.In the national standard of our country, the open control kernel system is called reconfigurability and has the following requirements: First, the configurable function and openness of MMC interfaces and protocols; Second, with fixed topology of control kernel, some modules can be substituted or added; Third, the topology of control kernel can be reconfigured..To realize the reconfigurability of CNC and fulfill the requirement of open CNC system, component technology and a open software framework is studied in this paper. First, through analyzing of CNC software structure, the following requirements of components are decided: System modules communicate with each other through dataflow: To accomplish the required operation, some modules need periodic execution; With different environment, some modules need different parameters to initialize; To realize the functional requirement of CNC system, some special control algorithms is needed. With the requirement talked above, a component model for CNC system is designed in this paper.Every component model needs a software framework to support it. According to researches of OSACA about the system framework, a CML layer is made above the RTOS, packaging the function of OS, providing the communication methods between components, defining the interfaces of components and providing the configuration of components, etc. With CML layer accomplished, the components for CNC system are implemented based on the functional requirement of CNC system.To make test of our component model and software framework, an open CNC system based on Mechatrolink fieldbus is constructed.At last, to test the reconfigurability of control kernel, with the reconfiguration of components' topology, some experiments are made on LanTian CNC using different hardwares, analog interface or fieldbus interface.