| As the control unit of numerical machine tools,CNC system is an indispensable part of modern manufacturing systems.Its function and performance directly affect manufacturing ability,precision and efficiency of machine tools.Research on high-end CNC systems has been the focus of attention of big manufacturing countries.Since the6 th five-year plan,China gradually carried out key projects on CNC systems.After nearly 40 years of development,there has been a number of CNC enterprises and products.However,high-end CNC systems are still monopolized by foreign brands,seriously hindering the transformation of China from big manufacturing coutry to powerful manufacturing country.With increasingly strict requirements of machining quality,efficiency and product indivisualization,there are more requirements for function and property customization of CNC.Openness,reconfigurability and expandability are important to shorten system development time,reduce development costs and avoid functional redundancy.However,in current CNC systems,functions are closely coupled in a real-time operating system,which has been the main obstacle to achieving above properties.As more customized functions are integrated,close coupling causes more complex architecture,redundant functions and high development and maintenance costs.Aiming at the above problems,this dissertation proposes an CNC system architecture with good expandability,reconfigurability and functional reusability called invisible computer control system(INC).By research on implementation techniques of INC,this dissertation provides foundation of new types of CNC systems.This dissertation analyses the operation mechanism of CNC system.By defining machine control instruction(MCI)and adopting compiling operation mechanism,MCI generation and execution process are decoupled.The dissertation establishes INC architecture by three sub modules: task management center,mobile terminal and motor controller,researches on the physical implementation,operation process,reconfiguration and reuse mechanisms and analyses the factors influencing INC functionality and performance.By this means,the real-time constraint of CNC operation is minimized,increasing the system openness.By analyzing the function and performance requirements,microservice architecture is used to build the software of task management center.Based on microservice architecture,function modules can be integrated locally or remotely throughout network environment.Task management center defines data types such as manufacturing task,device,service and MCI as information exchange between function modules.According to requriements of manufacturing scenarios,task management center integrates function modules dynamically and operates as a manufacturing task.Therefore,INC system realizes reconfiguration and function reuse property.Communication system is a module in task management center responsible for communication management with motor controller and remote function components.In aspect of communication with motor controller,to solve the problem of large data amount,features of MCI are analyzed,accordingly an efficient MCI compression method is proposed.The proposed method has advantage of simplicity,high compression efficiency and real-time decoding ability and significantly reduces the requirement of network bandwidth,which improve function reusability of task management center.In aspect of remote module integration,communication system applies Thrift framework to implement remote process call mechanism,realizing function service coorperation based on network.Motor controller can be implemented using bus or star topology and stores MCI by mass storage.The dissertation designs the motor controller architecture and prototype based on STM32 and FPGA.Multiple machine tool operation modes such as homing,jogging and auto running are realized.Utilizing a three-axis machine tool as experiment platform,the rightness of INC operation mechanism is validated through milling tests. |
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