导　　师： 王伟

学科专业： 081101

授予学位： 硕士

作　　者： ;

机构地区： 上海交通大学

摘　　要： 随着数控技术的高速发展,高档数控机床可以实现高速高精加工功能,多通道、多轴联动和复合加工功能。为了达到这些优异的性能,建立一条数控系统和计算机之间的高速实时数据传输通道成为关键。 本文数控系统设计的目标是确保计算机与伺服单元的通讯能够满足实时性与可靠性的要求。为了达到要求,采取了以下方案:首先,选用IEEE 1394总线连接计算机与伺服单元,因为应用高速高性能的数字伺服总线技术已经成为高档数控系统的一个重要特点和发展趋势。而IEEE 1394总线具有支持400Mbps的等时和异步传输、可热插拔、点对点架构灵活等特性已经成为高速伺服总线的首选。第二,计算机操作系统采用Windows+RTX/(Real Time Extension/),为数据传输软件提供了实时平台。最后,为了更进一步提高传输速度,根据开放式主机控制器接口/(OHCI/)协议,实现了DMA方式进行异步数据传输,这样使数据的传输过程变得更加透明,而且更有利于跟踪数据的传输状态。 本文主要研究了IEEE 1394标准,包括IEEE 1394体系结构、协议的分层结构及通信模型,这是整个系统的理论基础。之后分别从原理、特性和实际应用等角度详细分析了RTX实时环境。RTX作为Windows的子系统为那些具有强实时特性的Win32兼容的任务和线程提供了一种内核模式的可执行环境。另外,文中对数控系统的1394接口硬件作了详细的阐述。采用PCI-1394接口卡作为上位机接口,设计专门的1394前端模块作为伺服控制模块的接口。随后,本文重点研究了1394 OHCI协议,尤其对协议中DMA相关的寄存器做了细致分析,并且阐述了应用于数控系统的DMA方式传输原理,即通过RTX提供的API/(应用程序接口/)函数对1394芯片的寄存器进行直接的操作来实现数据的传输。之后,本文按照了“发送——接收”的传输模型,开发了1394 DMA方式数据传 With the rapid development of Numerical Control technology, a high-grade CNC machine tool can meet the reqirements such as high-speed and high-precision machining, as well as multi-channal and multi-axis control. It is important to build a data transmission channal between NC and PC, in order to realize the excellent performance of a high-grade CNC machine tool. The aim of the CNC system designed in this thesis is to ensure that the comunication between computer and servo unit can meet the requirements of real-time and reliability. The following schemes are adopted in order to meet the requirements mentioned above:Firstly, IEEE 1394 bus is selected to connect the computer and servo unit, because the application of the high-speed and high-performance numerical servo bus technology has become a major characteristic and trend in the development of the advanced CNC system. IEEE 1394 bus which has a flexible framework and supports synchronous and asynchronous data transmission with the speed up to 400Mbps, hot-pluggable has become the best choice of high-speed servo bus. Secondly, Windows+RTX /(Real Time Extension/) which is selected as the operation system of host computer provides the platform for the software of data transmission. Finally, asynchronous data transmission by DMA method is implemented based on Open Host Controller Interface /(OHCI/) protocol in order to improve the transmission speed further. Thus, the process of data transmission becomes as clear as possible, and it is beneficial to trace the status of data transmission. The thesis firstly makes a deep study of IEEE 1394 standards, including the system architecture of IEEE 1394, the hierarchical structure of the IEEE 1394 protocol and communication modal of IEEE 1394. This is the theoretical basis of our system. Then the RTX real time enviroment is analyzed in terms of principle, characteristics and application. RTX, as a subsystem for the Windows system, provides a kernel-mode execution environment for Win32 compatible tasks and threads

关 键 词： 总线 数据传输 实时性

领　　域： [自动化与计算机技术] [自动化与计算机技术]