振动对数控机床进给系统爬行的影响

发布时间：2018-06-20 10:21

本文选题：数控机床 + 机械进给系统　；参考：《内蒙古科技大学》2015年硕士论文

【摘要】：数控机床具有自动化程度高、适应性和灵活性强、加工精度高、生产效率高、有利于生产管理现代化和经济效益高等优点，综合了控制技术、伺服驱动和高精密检测等方面的技术。随着航空航天、汽车、能源和军备应用等方面的快速发展，，不仅零件的复杂程度越来越高，精度也越来越高，普通的加工机床根本不能满足其性能的要求和需要。另外，激烈的市场竞争也要求产品研制周期短、出厂效率高和质量达标等。故数控机床近几十年发展迅速，为社会提供了这种各样的高品质机械产品，提高了机械制造业的制造水平，为全世界带来了巨大的经济效益。我国目前大部分数控机床普遍存在爬行现象。爬行是数控机床在低速、重载或间歇的微量移动情况下，工作台出现的运动时快时慢或者时走时停的一种运动状态。爬行导致被加工件表面精度和加工精度变低，对刀具也有一定的损害作用，甚至造成零件报废或者机床停机。因此若能有效地改善数控机床的爬行，则能够提高数控机床的精度。我国主要以生产中低端数控机床为主，若能改善数控机床的爬行，则我国的轻工消费品将高速增长，数控机床也能在加工精度方面提高。本文在参考了大量资料后，通过对产生爬行的机械进给传动系统部分的运动情况分析后，应用机械进给传动系统的简化模物理型进行分析，从理论上推导出了当爬行出现时的临界速度计算公式，并在ADAMS中建立爬行仿真模型，明确了系统阻尼，系统刚度和驱动速度等各爬行因子对爬行的影响程度。其次，为了改善爬行，给工作台加模拟的正弦力和正弦振动源，调整外加力和振动源的频率与幅值，使其与弹簧产生的振动进行耦合，来消除爬行。事实上，由于弹簧传给工作台的振动是无规则的，故要想达到耦合振动难度很大，利用外加振动的方法能够改善爬行现象，并且取得了一定了效果。再次，根据振动对爬行的改善效果图和PID的性质，想到可以利用PID来控制爬行。在工作台上加入PID控制系统，整定三个增益参数，发现PID控制对爬行也起到了改善作用，并在加入振动后的模型上进一步加入PID控制，最终达到了完全抑制爬行的目的。
[Abstract]:Numerical control machine tools have the advantages of high automation, strong adaptability and flexibility, high machining precision, high production efficiency, favorable to the modernization of production management and high economic benefits. Servo drive and high precision detection and other aspects of technology. With the rapid development of aerospace, automobile, energy and armament applications, not only the complexity of the parts is becoming more and more complex, but also the precision is becoming higher and higher. The common machine tools can not meet the requirements and requirements of its performance. In addition, fierce market competition also requires a short period of product development, high factory efficiency and quality standards. Therefore, NC machine tools have developed rapidly in recent decades, providing the society with this kind of high quality mechanical products, improving the manufacturing level of mechanical manufacturing industry and bringing great economic benefits to the whole world. At present, most NC machine tools are crawling in our country. Crawling is a kind of motion state of CNC machine tool under the condition of low speed, heavy load or intermittent micro movement, the movement of the worktable appears fast and slow or stop when walking. Crawling results in lower surface and machining accuracy of the workpiece, which can also damage the cutting tool, and even lead to the scrapping of parts or machine tool shutdown. Therefore, if the crawling of NC machine tools can be improved effectively, the accuracy of NC machine tools can be improved. China mainly produces low-end numerical control machine tools. If we can improve the crawling of numerical control machine tools, the consumption of light industry will increase at high speed, and the machining accuracy of numerical control machine tools will also be improved. After referring to a lot of data, this paper analyzes the movement of the part of the mechanical feed transmission system which produces crawling, and analyzes the physical form of the simplified die of the mechanical feed transmission system. The calculation formula of critical velocity when crawling appears is deduced theoretically, and the creeping simulation model is established in Adams, and the influence degree of crawling factors such as system damping, system stiffness and driving speed on crawling is determined. Secondly, in order to improve the crawling, the simulated sinusoidal force and sinusoidal vibration source are added to the worktable, and the frequency and amplitude of the external force and vibration source are adjusted to make it coupled with the vibration produced by the spring, so as to eliminate the crawling. In fact, because the vibration transmitted from the spring to the worktable is irregular, it is very difficult to achieve the coupled vibration. The crawling phenomenon can be improved by using the method of external vibration, and some results have been obtained. Thirdly, according to the improved effect of vibration on crawling and the properties of pid, the author thinks that pid can be used to control crawling. The pid control system is added to the workbench and the three gain parameters are set. It is found that pid control also improves the crawling, and further adds pid control to the model after adding vibration, and finally achieves the goal of completely restraining crawling.
【学位授予单位】：内蒙古科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG659

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