【作者】 陈剑雄；

【导师】 林述温； 倪霞林；

【作者基本信息】 福州大学 ， 机械制造及其自动化， 2006， 硕士

【摘要】 数控系统的开放性是当今数控系统发展的主流,开放式数控系统研究的目的是开发一种模块化、可重构、可扩充的控制系统结构,以增强数控系统的柔性,从而可以快速地响应新的加工需求。本文在对开放式数控系统的国内外研究现状,现有开放式体系结构的特点以及存在的不足进行详细分析的基础上,围绕着如何实现开放式数控系统开放性、柔性化、模块化、标准化,结合现场总线以及嵌入式Linux系统的特点,提出了基于嵌入式Linux现场总线型开放式数控系统。并从体系结构、功能模块结构、通讯接口协议、软件平台功能分析、插补方式等方面论述系统的开放性及其实现途径。采用了模块化、层次化的体系结构设计方法,结合模块间的通讯要求以及现场总线的特点,提出了CAN总线的模块化的结构和采用PROFIBUS的单元化结构两种开放式体系结构方案。从控制系统结构特点、实时性、开放性、可扩展性以及成本等方面进行综合的评价和比较,确定了基于CAN总线的模块化结构的控制系统方案。研究了模块间通讯的模型、数据交换类型和数据量,由此设计出简单、实用的数据交换协议。分析了功能模块的硬件结构并设计相应的硬件电路。采用可扩展、可配置的程序设计,在实现可编程I/O接口的同时,允许用户功能子程序的介入。在基于嵌入Linux开放式数控系统的软件平台上,设计了软件系统的功能层次和软件模块。引入硬件抽象层的设计,将应用程序与硬件平台分离。采用多线程作为数控系统任务调度机制,开发了基于MiniGUI的开放式数控系统的图形用户界面,实现系统的管理、配置、显示等交互的功能。探讨了使用NURBS曲线插补数据格式G06统一表示各种曲线的转化方法。采取由人机接口模块离线连续粗插补,运动控制模块进行精插补的模式,对基于显式矩阵NURBS曲线插补算法进行验证。同时,为了满足现代制造对高精度加工的要求,对NURBS曲线预测-校正自适应插补算法进行初步研究。研究结果表明:基于CAN总线的模块化设计,实现可编程I/O接口,系统具有良好的开放性和互换性。应用嵌入式Linux、MiniGUI的软件平台,具有良好的可配置、剪裁的功能,减少了软硬件系统的冗余。采用统一的插补数据格式,使得各种轮廓插补简化到单个插补插补程序内。更多还原

【Abstract】 Nowadays, open architecture CNC systems are becoming one of the most important trend of CNC technology. The research purpose of open CNC systems is to build a modular, reconfigurable and expandable architecture to improve the system’s flexibility, and enable the systems to be re-developed,in order that CNC systems can be responsive to the market quickly and economically. After researching the recent situation of the abroad and domestic open CNC system, and the characteristic and the existential shortage of the current open architecture system, according to the way of realizing the characteristic of openness, flexibility, modularization, standardize for open CNC system, together with the feature of field-bus and embedded Linux system, this dissertation presents an open CNC system, which is basing on embedded Linux system and field-bus. Further more, some of the features and ways, such as architecture, hardware configuration, software platform, data format and interpolation,and how to realize the openness of system are also discussed. Adopting the modular and layers architecture design method, incorporate with the communication need between modules, as well as the characteristic of field-bus , this dissertation discusses two possible solutions, which are adopt CAN bus which called modularized structure and adopt PROFIBUS called unitization structure, for CNC control system. The comparison between these two solutions including the aspects of the features of control system, real-time characteristic, openness, extensibility and cost is conducted for integrative evaluation. Subsequently, the control system which called modular structure basing on CAN bus is selected to do further design. Research on the communication module , the types and bulk of data exchanging between modules,and then design a simple and practical data exchange agreement. Analyze the hardware structure of functional modules and then design the relative hardware circuit. Using the extensible and configurable programming method, realize programmable I/O, and allow user function subprograms insertion at the same time. On the software platform of open CNC system based on Linux, we divide the software system into several functional layers and software modules. Subsequently, introduce hardware abstract layer to the system, for separating application from hardware platform. Adopt multithreading as CNC system task scheduling mechanism,then develop a CNC graphical user interface based on MiniGUI, it realize the alternating function for systematical management, configuration, display etc. Discuss the translating method of NURBS as uniform internal data interface for different kinds of curves. Further more, introduce the mode of rawness interpolating by man-machine interface module and extractive interpolation by motion control module, for proceeding demonstration of NURBS curve interpolation based on explicit formulation matrices representation. Simultaneity, in order to satisfaction the requirement of modern manufacture for high precision processing,this dissertation do some preliminary study on forecast-adjustment adaptive interpolation algorithm for NURBS curve. The research demonstrates that modular design based on CAN bus,as well as programmable I / O interface,which bring favorable openness and exchangeability to the system. The platform of system software application based on embedded Linux, has better configurable and clipping function compared to the common PC and desktop Operating System, reduce the redundancy of software and hardware. Using uniform interpolation data format, so as to merge different kinds of curves interpolation into single interpolation program.更多还原