【作者】 张边；

【导师】 陈武柱；

【作者基本信息】 清华大学 ， 材料加工工程， 2002， 硕士

【摘要】 正文：目前国内外在激光加工中普遍应用的数控系统是一种专用型、封闭式的系统，难以扩展，价格昂贵，无法适应现代高柔性、低成本的加工要求 。因此，近年来具有良好的柔性和较低成本的开放式数控系统逐渐成为数控技术研究的热点，也代表了激光加工数控技术发展的方向。本论文的目标是结合我校激光加工研究中心实验研究基地建设的需要，研制一套可以同时应用于激光切割、激光热处理和激光焊接等多种加工方式的开放式多功能激光加工数控系统。该系统具有开放性、多功能性、智能性、高速加工等特点。本文重点阐述了该数控系统方案的选择、系统的组成及结构和一些关键数控技术的研究工作。在全面比较分析国内外现有的开放式数控加工技术，对比了各种可行性方案的基础上，采用了基于工业PC和PMAC运动控制卡的主从式数控系统设计方案。该方案利用标准化的ISA总线和标准化的Windows软件实现了开放性，为整套数控系统提供了一个优异的架构。本系统设计了一种基于四轴联动(X、Y、Z平动轴和C旋转轴)的机械平台，可以同时满足激光切割、激光表面处理和激光焊接等加工方式的运动要求。作者还采用了当今前沿的软件开发技术，使用Windows下的COM技术实现，设计了一种基于软件总线的软件架构，为高效率输入多种激光加工数据提供了软件基础。在接口板设计中采用了CPLD技术，利用VHDL语言进行硬件逻辑设计，使该套激光加工数控系统可以通过在线编程的方式随时更新和扩展系统的接口逻辑，实现系统的高度柔性化。提出了一种基于遗传基因算法的智能化激光切割辅助轨迹优化算法，成功地实现了激光切割时自动优化引弧孔、入弧点位置和封闭体切割顺序，既提高了激光切割的质量又保证了最短空程路径，提高了切割效率。由于本机床采用光束固定、工件运动的方式，因此运动部分的质量很大。在这种情况下最大加速度受限制，造成曲线激光加工时速度上不去且不稳定的严重问题。本论文通过使用PMAC的点位置时间(Position-Velocity-Time)模式，利用三次参数插补样条运动，成功地解决了这种低加速度下的重载高速稳定加工问题更多还原

【Abstract】 Content: The common numeric control (NC) system that is widely applied in current laser processing both domestically and internationally, is a kind of specialized and closed system. Due to its limitation in expansion and high price, the system cannot meet the requirements of high flexibility and low cost in today’s processing industry. Therefore, research on NC technology in recent years has been focused more and more on the open NC system with outstanding flexibility and low cost, which also represents the developing direction of laser-processing NC technology.This thesis aims at developing an open, multi-functional laser-processing NC system, partially for the Experiment and Research Base of Tsinghua Laser Processing Research Center. The system is expected to simultaneously operate several processing modes (including laser cutting, laser surface modification and laser welding), and demonstrate features of openness, multi-function, intelligent function and high-speed processing. The focus of the paper is on the design of NC system, its components and structure, and the study of some key NC technologies.After thorough comparison and analysis on the current open NC processing technologies in China and western countries, and on the basis of several feasible plans, the "Principle & Subordinate Design" based on industrial-PC and PMAC control-card is finally adopted. The design is open through its standardized ISA-line and Windows software, providing an excellent framework for the whole NC system.A mechanical platform based on the simultaneous movement of the four axes (X, Y, Z-translation and C-revolving) is developed in the system, which is suitable for the simultaneous movement of laser cutting, laser surface modification and laser welding. The author also adopts the leading technology in today’s software development and designs a software-mainline-based software frame, by using the COM-tech realization<WP=5>under Windows, which provides a software base for the high-speed input of laser-processing data.CPLD technology is applied in the design of mouthpiece boards, and the hardware logic is programmed in VHDL language. Thus, the laser processing NC system can update and expand its mouthpiece logic through on-line programming at any time, and achieve high flexibility.In the paper, an intelligent optimal calculation method for laser cutting assistant-path, based on genetic calculation, is also suggested. The method can automatically optimize the location of initiating point and start-cutting point and the sequence of closing object cutting. It can not only improve the quality of laser cutting but also guarantee the shortest laser-off path, which will improve the cutting efficiency. . Due to the application of fixed laser beam and moving workpieces, the machine has a large-quality moving part. As a result, the maximum acceleration is limited, which hinders the speed and the steadiness in laser processing of curves. By using the Position-Velocity-Time mode of PMAC and cubic parameter spline moving, the problem in low-acceleration processing is successfully solved in this paper.更多还原