层叠式柔版印刷机控制系统设计

发布时间：2018-08-13 14:05

【摘要】：目前层叠式柔版印刷机控制系统主要有两种控制方式,分别是PLC控制和继电器控制。二者均是控制机械主轴,通过主轴和各色组轴之间齿轮咬合进行传动,而这两种控制方式所依据的齿轮传动存在的机械磨损会导致整个印刷系统的精度降低、噪音大、同步性差、速度低等问题。如何解决系统中存在的此类问题是本课题研究的核心任务。本文以杭州项淮机械有限公司的层叠式柔版印刷机为研究对象,依据系统的工艺性能要求,对其控制系统进行了研究、改造和实施。本文首先对层叠式柔版印刷机的结构、工艺流程、各环节的传动方式进行了细致的分析研究。然后以此为基础,针对印刷精度不高和同步性差的问题,提出基于伺服电机拟合虚拟主轴(电子轴)传动的层叠式柔版印刷机控制方法。张力控制是整个项目的技术难点,实时保持张力稳定是精准印刷的关键。本文采用变比例PID控制算法,可实现张力的精准控制,同时在收卷时考虑到恒张力下卷径变化对产品的挤压,在收卷时采用锥度控制算法,随着卷径的变大收卷机构的张力逐渐减小,以保证机器在稳定运行时收卷机构不会压坏产品。在印刷色组的同步性控制环节,通过调节各色组伺服电机与虚拟主轴之间速度的耦合比以补偿由外部扰动引起的位置误差,实现控制色组之间印刷的同步性。该方法不仅能够提高系统的同步精度,同时能够满足系统的动态同步要求,通过调节套色误差解决印刷技术上套印精度低的问题。最后,在实施上本控制系统采用德国Beckhoff的Systemmanger伺服控制系统,控制器采用Beckhoff的工控机及TwinCAT控制平台,通过EtherCAT的IP网络协议,搭建了一个运动控制系统。通过系统调试和现场测试,以及性能分析,结果表明,本文设计的控制系统结构简单、扩展性强,而且大大减小了传动误差,提升了系统的响应速度、同步性能和印刷精度,完全满足系统工艺要求,使以往的缺陷得以很好的改善。
[Abstract]:At present, there are two main control modes in the control system of the laminated flexo printing press, namely, PLC control and relay control. Both of them control the mechanical spindle, which is driven by the gear bite between the spindle and the shafts of various colors, and the mechanical wear of the gear transmission based on these two control modes will result in the reduction of the accuracy and the noise of the whole printing system. Synchronization difference, low speed and other problems. How to solve such problems in the system is the core task of this research. In this paper, the control system of the cascade flexographic printing machine of Hangzhou Xianghuai Machinery Co., Ltd is studied, reformed and implemented according to the requirements of the system's technological performance. In this paper, the structure, technological process and transmission mode of laminated flexographic printing machine are analyzed and studied in detail. Then, aiming at the problems of low printing precision and poor synchronicity, a new control method of cascaded flexographic printing machine based on servo motor fitting virtual spindle (electronic shaft) transmission is proposed. Tension control is the technical difficulty of the whole project, and maintaining tension stability in real time is the key of precision printing. In this paper, the variable proportional PID control algorithm is used to control the tension accurately. At the same time, considering the constant tension under the rolling diameter change to the extrusion of the product, the taper control algorithm is used in the coiling process. The tension of the winder decreases gradually with the increase of the winding diameter, so as to ensure that the winder will not be crushed when the machine is running stably. In the synchronism control of printing color group, by adjusting the coupling ratio of speed between servo motor and virtual spindle of each color group to compensate the position error caused by external disturbance, the synchronism of printing between color groups can be realized by adjusting the coupling ratio of the speed between each color group servo motor and virtual spindle. This method can not only improve the synchronization accuracy of the system, but also meet the requirement of dynamic synchronization of the system. The problem of low accuracy of overprinter in printing technology can be solved by adjusting the color error. Finally, the Systemmanger servo control system of German Beckhoff is adopted in the implementation of the control system. The controller adopts the Beckhoff industrial control computer and TwinCAT control platform. Through the IP network protocol of EtherCAT, a motion control system is built. Through system debugging, field testing and performance analysis, the results show that the control system designed in this paper is simple in structure, strong in expansibility, and greatly reduces the transmission error, and improves the response speed, synchronization performance and printing accuracy of the system. Fully meet the system process requirements, so that the previous defects can be well improved.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP273;TS873

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