【作者】 陈星；

【导师】 钱晓龙；

【作者基本信息】 东北大学 ， 控制理论与控制工程， 2010， 硕士

【摘要】 在带钢表面上进行热镀锌处理是带钢防止腐蚀的一种重要方法,同时带钢表面的镀层厚度决定了带钢抗腐蚀的时间长短。然而,如何按照客户需求进行精确控制镀层厚度对提高带钢产品质量,降低生产成本具有重要意义。就目前而言,我国的先进热镀锌生产线均引自国外,所以研究带钢表面镀层厚度控制对于提高我国自主知识产权,开发自主的镀层厚度控制系统具有现实意义。本文对带钢连续热镀锌生产线中的镀层厚度控制系统进行了深入研究,该控制系统包括带钢镀层预设定控制、带钢镀层厚度横向误差控制以及带钢镀层厚度纵向平均控制。根据CLECIM公司(法国克莱希姆公司)开发的镀层厚度模型,其带钢表面镀层厚度与喷气压力P、气刀和带钢之间的水平距离H以及气刀唇缝L具有内在的函数关系。其中,带钢镀层预设定控制主要完成这三个控制量的设定值计算；带钢镀层纵向平均控制是通过喷气压力P和水平距离H的调节来提高带钢纵向平均镀层厚度的精度；横向镀层误差控制是控制气刀唇缝L以改善带钢横向镀层的均匀度。带钢镀层厚度控制系统采用传统PID控制器进行控制带钢的镀层厚度。然而,在现场具有强干扰的情况下,喷气压力P和工艺段线速度V会发生波动造成镀层厚度模型参数的改变,导致传统PID控制的效果受到影响。针对这种情况,本文在采集大量现场数据的基础上,使用最小二乘法对Edward镀层厚度模型进行参数辨识,以辨识后的Edward镀层厚度模型为被控对象。本文是在喷气压力P没有饱和的情况下,从调节压力的角度出发,采用原有系统模型的压力补偿和速度补偿,设计了基于模糊PID控制的带钢镀层纵向平均控制系统。仿真结果表明,模糊PID控制器与传统PID控制器控制效果相比,调节时间短,超调减小,鲁棒性增强等特点,使原系统控制效果得到优化,有利于提高带钢表面镀层的质量。更多还原

【Abstract】 The galvanizing on the surface of the steel sheet is an important method for steel anticorrosion. The anticorrosion time is decided by the coating weight on surface of galvanized steel sheet. It is very important to control coating weight precisely according to customer’s demands for improving product quality and reducing cost. Nowadays, the advanced continuous galvanized steel sheet import from foreign. The research on coating weight control is useful to improve proprietary intellectual property and develop proprietary coating weight control system.In this paper, the coating control system in continuous galvanized steel sheet is analyzed deeply, which include coating model preset, longitudinal coating mean control and transverse coating deviation control. In CLECIM coating model, the coating weight is the function of air pressure, distance from air knives to strip and air knives lip gap. The model preset is used for calculating reference values of control variables. In the longitudinal mean control, air pressure and distance are controlled to achieve precise and mean coating weight. And the transverse deviation controls air knives lip gap to improve the coating uniform.The coating weight of the steel is controlled by the coating control system through the traditional PID control. However, there are so strong disturbance in the industry fields that some model parameters are changed, such as air pressure, line speed. In this way, the effort of the coating control system is affected.In this situation, the fuzzy PID controller is introduced into the longitudinal coating mean control system, which adopts the Edward coating weight model. The model is identified using the least square approximation based on the real measured data. The simulation results indicate the fuzzy controller acquires shorter overshoot, shorter adjusting time and greater robustness. Thus, the effort of control system and quality of coating weight on the steel are improved.更多还原