The Design And Implementation Of MiniCNC Control System Based On Embedded Platform

The CNC computer numeric control is a control system that automatically controls the mechanical quantity and switching amount of the actuator such as position,displacement,speed and acceleration using digital signals.The traditional CNC system controls part is closed,the use threshold is high,the price is expensive,it is difficult to popularize,and it is unable to cope with the growing demand for small and medium batch production.The open CNC system is based on computer-rich software and hardware resources.PC is used as the core of the control system.The software can realize the motion control,which can save the cost of the dedicated hardware,thus greatly reducing the cost of the control system and facilitating the numerical control system.popular.The MiniCNC control system designed in this paper is based on the open CNC system structure system.Based on the embedded platform,the motion control of the processing platform is realized by expanding and adjusting the open source control software.This paper first introduces the development trend of CNC system at home and abroad,analyzes the requirements of MiniCNC control system,and proposes the design scheme of MiniCNC control system based on embedded platform.The mainstream embedded platform is studied,and the control system scheme based on Raspberry Pi and the control system scheme based on BeagleBone Black are designed.Through real-time testing of the two schemes,the stepping pulse generated by the Raspberry Pi through the control software has large jitter.According to the processing precision requirements,BeagleBone Black is finally selected as the embedded platform solution of the MiniCNC control system.The design and development of the MiniCNC control system includes the design and development of electronic control systems and the design and development of application software.The electronic control system realizes the matching control of the MiniCNC processing platform.The matching is divided into two aspects.One is to configure the multiplexing function of the general-purpose input and output pins of the BeagleBone Black through the device tree file.The design and development of the electrical adapter expansion board connects the BeagleBone Black pin to the processing platform hardware interface to achieve physical interface matching;the second is to abstract the processing platform hardware device into a HAL component with a HAL pin,in the hardware abstraction layer.The pins of each HAL component are connected to complete the hardware interface identification on the control software level,and the matching control of the feed axis,the spindle and the manual pulse generator of the processing platform is realized.The milling machine processing platform is reconfigured in the hardware abstraction layer to simulate the machining function of the lathe and realize the functional combination of the control system.The MiniCNC application software includes an operation interaction module and a data management module.This paper realizes the easy-to-use MiniCNC operation interaction module by establishing a message channel based on NML message mechanism and using Python plus Glade design.The data management module implements data interaction with the MiniCNC teaching system,including a login management module,a function selection module,and a data processing module.The data management module is implemented by Python,and realizes access to the teaching system MySQL database through mysqlclient.The login management module obtains user information from the database to perform login verification of the control system,and the data processing module processes the user's operation information and transmits it to the database in real time.The system performs numerical control related data analysis based on the operation data,and realizes the networking of the numerical control system.The test part of the MiniCNC control system includes testing of the electronic control system,testing of the application software,and testing of the overall machining function.The test results show that the MiniCNC control system designed and implemented in this paper can control the various units of the processing platform,and realize the user login management and operation data processing functions.The CNC system is capable of milling and lathe machining,and the actual machining capacity meets the requirements.