ARM And CPLD-based Design And Implementation Of CNC Control System

The core of CNC machine tools is industrial equipment manufacturing.At the same time, NCtechnology can largely reflect the industrial manufacturing capacity. NC developed countries adjusttheir direction to the high-end CNC machine tools to retain the key competitiveness of industry andeconomy. CNC equipment is in transition, we must vigorously develop high-end CNC, but thedevelopment of middle-end and low-end CNC machine can not be ignored. Therefore, the new typeof efficient and inexpensive CNC is proposed for the supplement of middle-end and low-end CNCmachine.We achieve the CNC system based on ARM+CPLD system architecture. The CNC system isconstituted by the main-board, backplane interfaces board and key input board. Among them,STM32F407ZGT6is selected as the main processor and EPM1270T144C5N(one of the CPLDdevices) is logic control devices in the main board. And realize the communication between themain processor and CPLD device by FSMC interface. The main board is used to complete thecomplex operation, code explanation, interpolation algorithm task scheduling and so on. Interfaceboard of CNC is designed to achieve the driver isolation and filtering of electric signal. While thekeypad board is an important part when system is need to response external input. The study of thisproject as follows:(1)、This project analyzes the architecture and principle of CNC maching system. The principleof cutting tool, compensation and interpolation is mainly included. The paper proposes and analyzesthree interpolation algorithms: point by point comparison, digital integration and minimumdeviation method.(2)、The paper introduces design and implementation of NCS hardware, which mainlyconstituent parts are main board and interfaces board.Then the main board hardware block diagramis given, and circuit principle and implementation are described. Interfaces board gives thedefinition of each signal circuit part and implements the connection of interface which the maininverter, encoder, hand wheel, dual-axis servo system is included.(3)、This project designs and implements the logic control code of NCS.The communicationprotocol between ARM and CPLD is realized, and also self definition of per register. Minimumdeviation method of interpolation algorithm is achieved. The principles of spindle encoder feedbackand handwheel signals are discussed. Then, the logic control code of CPLD is also realized.The system has been last nearly a year‘s research and debugging. It can achieve the most basicfunctions of the CNC system.NCS can achieve the interpolation precision reach the um level. The maximum feed rate is up to15m/min. The outline sharp of lines, arcs, threads, parabola and ellipsehas reached the industrial process requirements. Lastly, the reliability and continuous working hoursof NCS are both meet the requirements of machine tool industry industrial.