Architecture Modelling and Task Scheduling of an Integrated Parallel CNC System in Docker Containers Based on Colored Petri Nets

With the diversification of product types and the development of complex CNC system functions, reconfigurable, and extensible CNC system must be developed to meet the needs of industrial production in the new era. To optimize the original architecture between the CNC system and the machine tool, and to improve the integration level of the industrial control system, an integrated parallel CNC system which could control multiple CNC machine tools based on high performance multi-core processor is proposed in this paper. Based on the virtualize container technology, the functional modules of the CNC system, such as the interpreter module and interpolation module, operate separately on each Docker containers. The system scheduling module uniformly schedules above functional modules and caches the data generated by each module to maximize the processing efficiency and resource utilization. For the modeling of system architecture, the colored Petri nets are used to establish the models of CNC system and task scheduling. Two strategies of task scheduling which based on task dependencies and data flow are presented to determine the priority of system function threads. According to the developed test platform, the real time of the virtual system environment, real-time system environment, and the communication module of integrated CNC are analyzed. Furthermore, test results show that the proposed integrated parallel CNC system has the ability of centralized control of two machine tools synchronously.