CN102912275B - Automatic control system for coating thickness of hot galvanizing line - Google Patents
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- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 9
- 239000011701 zinc Substances 0.000 description 9
- 229910052725 zinc Inorganic materials 0.000 description 9
- 239000002994 raw material Substances 0.000 description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
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Abstract
本发明提供一种冷轧热镀锌线镀层厚度控制系统，包括气刀、测厚仪、工业PC机、PLC控制器、镀层厚度控制程序，控制程序运行在工业PC中，工业PC机与PLC控制器之间采用PROFIBUS？DP现场总线连接，PLC控制器采集镀层厚度实际值和生产过程数据发送到工业PC机中，控制程序采用串级控制方法，利用常规PID密集采样优势将副回路设计成随动系统，主回路采样周期为副回路的50-100倍，控制程序根据镀层厚度实际值和生产过程数据实时计算气刀压力、间距、框架位置设定值并发送到PLC控制器中，实现气刀压力、间距、框架位置调整，同时还设计了手动/自动模式无扰动切换和换卷过程镀层变规格切换控制。本发明能够快速消除镀层厚度偏差，在变规格和升降速过程中具有很好的控制效果。<!--1-->
The invention provides a coating thickness control system for a cold-rolled hot-dip galvanizing line, including an air knife, a thickness gauge, an industrial PC, a PLC controller, and a coating thickness control program. The control program runs in the industrial PC, and the industrial PC and the PLC Using PROFIBUS between controllers? DP field bus connection, the PLC controller collects the actual value of the coating thickness and the production process data and sends them to the industrial PC. The cycle is 50-100 times that of the auxiliary circuit. The control program calculates the air knife pressure, spacing, and frame position setting values in real time according to the actual value of the coating thickness and the production process data and sends them to the PLC controller to realize the pressure, spacing, and frame of the air knife. Position adjustment, at the same time also designed the manual/automatic mode without disturbance switching and coating change specification switching control during coil changing process. The invention can quickly eliminate the thickness deviation of the plating layer, and has a good control effect in the process of specification change and speed up and down. <!--1-->
Description
技术领域 technical field
本发明属钢铁生产设备技术领域，适用于热镀锌生产线的镀层厚度控制。The invention belongs to the technical field of iron and steel production equipment, and is suitable for coating thickness control of a hot-dip galvanizing production line.
背景技术 Background technique
热镀锌板因其良好的耐腐蚀性被广泛应用于建筑、家电、汽车等行业。近些年来，随着热镀锌板市场竞争日益激烈，用户对热镀锌板质量的要求越来越高。镀层厚度及其匀性是评价镀锌板质量的一项重要指标，镀层太薄影响产品的抗腐蚀性，镀层太厚影响产品的点焊性和附着性同时造成锌原料的浪费。目前，国内多数热镀锌生产线对镀层厚度的控制依然采用传统的控制方法，即由操作人员依据经验对设定值进行手工调整。手工调整不可避免地会引起过薄或超厚，最终导致镀锌产品质量下降和锌原料的浪费。因此开发高性能的锌层厚度自动控制系统对于提高产品质量和节约原料消耗具有重要意义。Hot-dip galvanized sheets are widely used in construction, home appliances, automobiles and other industries due to their good corrosion resistance. In recent years, with the increasingly fierce competition in the hot-dip galvanized sheet market, users have higher and higher requirements for the quality of hot-dip galvanized sheets. The thickness and uniformity of the coating are an important indicator for evaluating the quality of galvanized sheets. Too thin a coating affects the corrosion resistance of the product, and too thick a coating affects the spot weldability and adhesion of the product and causes waste of zinc raw materials. At present, most domestic hot-dip galvanizing production lines still adopt the traditional control method for the control of coating thickness, that is, the operator manually adjusts the set value based on experience. Manual adjustment will inevitably lead to over-thinness or over-thickness, which will eventually lead to a decline in the quality of galvanized products and a waste of zinc raw materials. Therefore, the development of a high-performance automatic control system for zinc layer thickness is of great significance for improving product quality and saving raw material consumption.
目前，世界各主要热镀锌工艺厂家在总结生产经验基础上，已形成了一套自己的控制系统。不同厂家热镀锌镀层控制系统采用的硬件设备基本相同，执行机构采用气刀，检测设备采用冷态测厚仪，但在控制策略和控制模型上互不相同，这也决定了系统的控制效果。At present, the world's major hot-dip galvanizing process manufacturers have formed a set of their own control systems on the basis of summarizing production experience. The hardware equipment used in the hot-dip galvanized coating control system of different manufacturers is basically the same, the actuator adopts air knife, and the detection equipment adopts cold thickness gauge, but the control strategy and control model are different from each other, which also determines the control effect of the system .
“热镀锌线锌层厚度的闭环控制简介”(刘海龙，四川冶金，200628(6))，介绍了VAICLACIM公司的镀层厚度控制系统，系统包括设定值模型、前馈闭环控制回路和反馈闭环控制回路。设定值模型采用模糊控制算法建立，描述镀层厚度与气刀压力、气刀间距、运行速度之间的关系，设定值模型计算气刀压力、气刀间距初始设定值。前馈控制消除速度波动带来的扰动，速度变化时维持镀层厚度不变，通过调节气刀压力来消除速度变化引起的镀层厚度波动。通过镀层厚度与速度、气刀压力、气刀间距之间的近似线性关系，间接计算出气刀压力附加设定值。反馈闭环控制回路采用气刀压力、间距联合调节控制方式，采用气刀压力优先调节方式，当压力调节达到限幅时保持压力设定值不变进行间距调节。根据镀层厚度实际值，通过镀层厚度与速度、气刀压力、气刀间距之间的近似线性关系，计算气刀压力和间距的附加设定值。控制策略，首先根据设定值模型计算出气刀压力、气刀间距的初始设定值；前馈控制消除速度波动引起的厚度偏差，根据速度变化计算气刀压力的附加设定值；反馈控制以单侧表面平均镀层厚度和两侧表面镀层厚度偏差为控制目标，通过压力调节消除平均镀层厚度偏差，通过气刀喷嘴开口度调节消除两侧镀层厚度偏差。此系统能够对镀层厚度实现闭环自动控制，但是前馈和反馈闭环控制回路中对控制器增益进行了线性化处理，认为镀层厚度与气刀间距、气刀压力、运行速度之间是线性关系，而气刀压力、间距与镀层厚度之间是非线性关系，尤其是气刀间距与镀层厚度之间存在较强的非线性，因此进行线性化处理存在较大误差。"Introduction to closed-loop control of zinc layer thickness in hot-dip galvanizing line" (Liu Hailong, Sichuan Metallurgy, 200628(6)), introduced the coating thickness control system of VAICLACIM company, which includes a set value model, a feed-forward closed-loop control loop and a feedback closed-loop Control loop. The set value model is established by fuzzy control algorithm to describe the relationship between coating thickness and air knife pressure, air knife distance and running speed. The set value model calculates the initial set value of air knife pressure and air knife distance. Feedforward control eliminates the disturbance caused by speed fluctuations, maintains the coating thickness when the speed changes, and eliminates the coating thickness fluctuations caused by speed changes by adjusting the air knife pressure. The additional setting value of the air knife pressure is indirectly calculated through the approximate linear relationship between the coating thickness and the speed, the air knife pressure, and the distance between the air knife. The feedback closed-loop control loop adopts the joint adjustment control mode of air knife pressure and spacing, and adopts the priority adjustment mode of air knife pressure. When the pressure adjustment reaches the limit, keep the pressure setting value unchanged to adjust the spacing. According to the actual value of coating thickness, through the approximate linear relationship between coating thickness and speed, air knife pressure, and air knife spacing, the additional set value of air knife pressure and spacing is calculated. The control strategy firstly calculates the initial set value of air knife pressure and air knife spacing according to the set value model; feedforward control eliminates the thickness deviation caused by speed fluctuation, and calculates the additional set value of air knife pressure according to the speed change; feedback control uses The average coating thickness on one side and the coating thickness deviation on both sides are the control targets. The average coating thickness deviation is eliminated by pressure adjustment, and the coating thickness deviation on both sides is eliminated by adjusting the opening of the air knife nozzle. This system can achieve closed-loop automatic control of the coating thickness, but the controller gain is linearized in the feedforward and feedback closed-loop control loops. It is considered that the coating thickness is linear with the air knife spacing, air knife pressure, and operating speed. However, there is a nonlinear relationship between the air knife pressure, spacing and coating thickness, especially the strong nonlinear relationship between the air knife spacing and coating thickness, so there is a large error in the linearization process.
“镀层厚度系统DMC串级控制仿真研究”(姚刚霞，微计算机信息，200723(25))，介绍了武钢热镀锌线镀层厚度自动控制系统，系统采用DMC预测控制算法，根据镀层厚度和速度变化计算气刀压力设定值。采用DMC预测控制解决了模型失配时系统鲁棒性问题，但是文章只讲述了通过压力调节进行镀层厚度控制的仿真试验结果，实际应用过程中仅通过调整气刀压力来控制镀层厚度是不够的。"Simulation Research on DMC Cascade Control of Coating Thickness System" (Yao Gangxia, Microcomputer Information, 200723(25)), introduces the automatic control system of coating thickness of Wuhan Iron and Steel's hot-dip galvanizing line. The system adopts DMC predictive control algorithm, according to coating thickness and speed changes Calculate the air knife pressure setting. DMC predictive control is used to solve the problem of system robustness when the model is mismatched, but the article only describes the simulation test results of coating thickness control through pressure adjustment, and it is not enough to control the coating thickness by adjusting the pressure of the air knife in the actual application process .
“宝钢热镀锌机组锌层重量控制模型的应用”(林莉军，宝钢技术，2007(4))，介绍宝钢热镀锌线的锌层厚度控制系统，系统包括预测模型和反馈闭环控制回路。预测模型计算气刀压力和气刀间距初始设定值，反馈控制回路计算气刀压力和气刀间距附加设定值。系统能够实现镀层厚度自动控制，但是预测控制回路和反馈控制回路都是建立在模型基础上，控制性能过于依赖模型精度，当模型失配时控制效果不佳。"Application of zinc layer weight control model in Baosteel hot-dip galvanizing line" (Lin Lijun, Baosteel Technology, 2007 (4)), introducing the zinc layer thickness control system of Baosteel's hot-dip galvanizing line. The system includes a predictive model and a feedback closed-loop control loop. The predictive model calculates the initial set values of the air knife pressure and the air knife spacing, and the feedback control loop calculates the additional set values of the air knife pressure and the air knife spacing. The system can realize the automatic control of coating thickness, but the predictive control loop and feedback control loop are based on the model, the control performance is too dependent on the model accuracy, and the control effect is not good when the model is mismatched.
目前，国内大多数热镀锌生产线的镀层厚度控制依然由操作工手动调整完成，不可避免地会引起镀层厚度偏差过大。现有的镀层厚度自动控制系统中也存在调节时间长和控制效果不佳的缺陷。At present, the coating thickness control of most domestic hot-dip galvanizing production lines is still manually adjusted by the operator, which will inevitably cause excessive coating thickness deviation. The existing automatic coating thickness control system also has the defects of long adjustment time and poor control effect.
发明内容 Contents of the invention
本发明的目的在于提供一种热镀锌线镀层厚度自动控制系统，本系统能够快速消除镀层厚度偏差，尤其是变规格和升降速过程中具有很好的控制效果，从而达到提高成材率和降低锌原料消耗的目的。The object of the present invention is to provide an automatic coating thickness control system for a hot-dip galvanizing line. This system can quickly eliminate the coating thickness deviation, especially in the process of changing specifications and speed up and down, and has a good control effect, so as to improve the yield and reduce the The purpose of zinc raw material consumption.
为了实现上述发明目的，本发明提供一种热镀锌线镀层厚度自动控制系统，包括以下内容：In order to achieve the purpose of the above invention, the present invention provides a hot-dip galvanizing line coating thickness automatic control system, including the following:
1、系统包括气刀、测厚仪、工业PC机、PLC控制器、镀层厚度控制程序。镀层厚度控制系统中气刀是执行机构，测厚仪是检测机构，控制程序运行在工业PC中。工业PC机与PLC控制器之间采用PROFIBUSDP现场总线连接，测厚仪与PLC之间采用工业以太网连接。PLC控制器采集镀层厚度实际值和生产过程数据发送到工业PC机中，镀层厚度自动控制程序根据镀层厚度实际值和生产过程数据实时计算气刀压力、间距、框架位置设定值并发送到PLC控制器中，实现气刀压力、间距、框架位置调整。1. The system includes air knife, thickness gauge, industrial PC, PLC controller, and coating thickness control program. In the coating thickness control system, the air knife is the executive mechanism, the thickness gauge is the detection mechanism, and the control program runs in the industrial PC. The PROFIBUSDP field bus is used to connect the industrial PC and the PLC controller, and the industrial Ethernet is used to connect the thickness gauge and the PLC. The PLC controller collects the actual value of the coating thickness and the production process data and sends them to the industrial PC. The automatic control program of the coating thickness calculates the air knife pressure, distance, and frame position setting values in real time according to the actual value of the coating thickness and the production process data and sends them to the PLC. In the controller, the adjustment of air knife pressure, spacing and frame position is realized.
镀层厚度控制程序采用串级控制，副回路采用常规PID控制算法，利用常规PID密集采样优势将副回路设计成随动系统。主回路采样周期为副回路采样周期的50-100倍，通过多层次控制把抗干扰性和鲁捧性这两个相互矛盾的性能要求分割到不同层次进行处理。系统的主回路为镀层厚度闭环控制回路，系统的副回路为气刀装置的压力、间距、框架位置闭环控制回路。主回路实时地为副回路计算设定值数据，包括气刀压力、间距、框架位置设定值。The coating thickness control program adopts cascade control, the secondary loop adopts conventional PID control algorithm, and the secondary loop is designed as a servo system by taking advantage of conventional PID intensive sampling. The sampling period of the main loop is 50-100 times of the sampling period of the secondary loop. Through multi-level control, the two contradictory performance requirements of anti-interference and robustness are divided into different levels for processing. The main loop of the system is a closed-loop control loop of coating thickness, and the secondary loop of the system is a closed-loop control loop of pressure, spacing, and frame position of the air knife device. The main loop calculates the set value data for the secondary loop in real time, including the set values of air knife pressure, spacing, and frame position.
2、主回路由气刀间距预设定、前馈闭环控制、反馈闭环控制三部分组成。2. The main circuit is composed of three parts: air knife spacing preset, feed-forward closed-loop control, and feedback closed-loop control.
(1)气刀间距预设定，根据生产过程经验数据，建立原料带钢厚度和镀层厚度与气刀间距之间关系的二维数据表格，通过查表法选择气刀间距设定值。(1) The air knife spacing is pre-set. According to the experience data of the production process, a two-dimensional data table of the relationship between the raw material strip thickness and coating thickness and the air knife spacing is established, and the set value of the air knife spacing is selected by the table look-up method.
(2)前馈闭环控制通过前馈控制模型计算气刀压力基础设定值。根据生产过程数据采用最小二乘法回归出描述镀层厚度w与带钢速度v，气刀压力p，气刀间距d等参数之间的关系的数学模型。模型输入为镀层厚度设定值、速度实际值、气刀间距实际值，输出为气刀压力设定值，当镀层厚度设定值或带钢速度或气刀间距发生变化时系统根据前馈模型计算气刀压力设定值，通过改变气刀压力来实现镀层厚度控制。(2) Feed-forward closed-loop control calculates the basic set value of the air knife pressure through the feed-forward control model. According to the production process data, the least square method is used to regress the mathematical model describing the relationship between the coating thickness w and the strip speed v, the air knife pressure p, and the air knife distance d. The input of the model is the set value of the coating thickness, the actual value of the speed, and the actual value of the air knife spacing, and the output is the set value of the air knife pressure. Calculate the set value of the air knife pressure, and realize the coating thickness control by changing the air knife pressure.
(3)反馈闭环控制采用双面平均镀层厚度和偏差镀层厚度联合控制方式。以双面平均镀层厚度为控制目标，通过气刀压力调节消除双面平均镀层厚度误差。以偏差镀厚为控制目标，通过调节气刀框架位置，保证带钢位于气刀的中心位置，消除带钢上下表面的镀层厚度偏差。反馈控制针对控制对象大滞后、非线性、强耦合等特性采用无模型自适应控制器，消除模型失配误差和系统长期累积误差。(3) The feedback closed-loop control adopts the joint control method of double-sided average coating thickness and deviation coating thickness. Taking the average coating thickness on both sides as the control target, the error of the average coating thickness on both sides is eliminated by adjusting the air knife pressure. Taking the deviation plating thickness as the control target, by adjusting the position of the air knife frame, the strip steel is at the center of the air knife, and the deviation of the coating thickness on the upper and lower surfaces of the strip steel is eliminated. Feedback control uses a model-free adaptive controller for the characteristics of the control object, such as large lag, nonlinearity, and strong coupling, to eliminate model mismatch errors and long-term cumulative errors in the system.
3、副回路包括气刀压力闭环控制、气刀间距位置闭环控制回路。气刀压力控制采用比例积分控制器，气刀间距、气刀框架控制采用比例控制器。3. The auxiliary circuit includes air knife pressure closed-loop control and air knife distance position closed-loop control loop. Proportional-integral controller is used for air knife pressure control, and proportional controller is used for air knife spacing and air knife frame control.
4、镀层厚度控制手动/自动模式无扰动切换控制方法。手动模式时主回路不参与控制，副回路气刀压力、间距位置、框架位置设定值由操作工手动给定。气刀间距预设定回路跟随当前手动设定值，前馈控制模型实时计算气刀压力基础设定值，反馈控制中偏差镀层厚度控制回路停止计算，平均镀层厚度控制回路设定值为当前气刀压力手动设定值与前馈控制模型计算的基础设定值之差。当由手动切换到自动模式时，气刀间距位置保持不变，偏差镀层厚度控制回路开始计算，当前气刀压力设定值作为双面平均镀层厚度主回路输出的初始设定值。自动模式切换到手动模式时，锁存主回路前一扫描周期输出的设定值作为副回路的初始设定值，主回路控制切除。4. Coating thickness control manual/automatic mode without disturbance switching control method. In the manual mode, the main circuit does not participate in the control, and the setting values of air knife pressure, distance position and frame position of the secondary circuit are manually given by the operator. The air knife spacing preset loop follows the current manual setting value, the feedforward control model calculates the basic set value of the air knife pressure in real time, the deviation coating thickness control loop stops calculation during feedback control, and the average coating thickness control loop set value is the current air knife pressure. The difference between the manually set value of the knife pressure and the base set value calculated by the feedforward control model. When switching from manual to automatic mode, the air knife spacing position remains unchanged, the deviation coating thickness control loop starts to calculate, and the current air knife pressure setting value is used as the initial setting value output by the main loop of the double-sided average coating thickness. When the automatic mode is switched to the manual mode, the set value output by the main loop in the previous scanning cycle is latched as the initial set value of the secondary loop, and the main loop control is cut off.
5、换卷过程镀层厚度控制方法。换卷过程中前馈控制模型始终进行计算。如果换卷过程镀层厚度规格不变，当焊缝到达气刀时将当前气刀间距设定值和反馈控制器输出值锁存，直到焊缝经过测厚仪时锁存解除。如果换卷过程镀层厚度规格改变，当焊缝到达气刀时首先将反馈控制器输出清零，然后通过查表选择气刀间距预设定值进行气刀间距调整，当焊缝进过测厚仪时反馈控制器开始计算气刀压力附加设定值。5. Coating thickness control method in coil changing process. The feed-forward control model is always calculated during lap change. If the thickness specification of the coating remains unchanged during the coil change process, when the weld seam reaches the air knife, the current set value of the air knife distance and the output value of the feedback controller are latched until the weld seam passes through the thickness gauge and the latch is released. If the thickness specification of the coating changes during coil change, when the weld seam reaches the air knife, first clear the output of the feedback controller, and then select the preset value of the air knife spacing by looking up the table to adjust the air knife spacing. The instrument time feedback controller starts to calculate the additional set value of the air knife pressure.
镀层厚度自动控制系统投入运行消除了手动操作存在的一些缺陷，产品的镀层厚度能够快速达到目标值，调节过程小于2分钟(宝钢系统小于3分钟)，镀层厚度偏差和均匀性有所改善，同时还降低了锌原料消耗，不同规格镀厚降低锌原料消耗1~4g/m2。The coating thickness automatic control system has been put into operation to eliminate some defects in manual operation. The coating thickness of the product can quickly reach the target value. The adjustment process is less than 2 minutes (Baosteel’s system is less than 3 minutes), and the coating thickness deviation and uniformity have been improved. At the same time It also reduces the consumption of zinc raw materials, and the consumption of zinc raw materials is reduced by 1~4g/m 2 for plating thicknesses of different specifications.
附图说明 Description of drawings
图1热镀锌镀层厚度控制示意图；Figure 1 Schematic diagram of hot-dip galvanized coating thickness control;
图2控制系统构成图；Figure 2 Control system composition diagram;
图3前馈控制模型消除速度扰动的控制效果曲线；Fig. 3 The control effect curve of the feed-forward control model to eliminate the speed disturbance;
图4双面平均镀层厚度控制效果曲线；Figure 4 double-sided average coating thickness control effect curve;
图5双面偏差镀层厚度控制效果曲线。Fig. 5 Curve of double-sided deviation coating thickness control effect.
具体实施方式 Detailed ways
下面结合附图对本发明具体实施方式作进一步的说明：The specific embodiment of the present invention will be further described below in conjunction with accompanying drawing:
国内某热镀锌线，测厚仪距离气刀150米，运行速度50-150米/分。6种常用镀厚规格80、100、120、180、220、275g/m2。For a hot-dip galvanizing line in China, the distance between the thickness gauge and the air knife is 150 meters, and the running speed is 50-150 meters per minute. 6 common plating thickness specifications 80, 100, 120, 180, 220, 275g/m 2 .
1、系统配置。1. System configuration.
选用德国FOEN公司气刀、美国THERMO公司镀层测厚仪、气刀控制器选用SIEMENS公司S7-300PLC控制器、工业PC机选择SIEMENS公司IPC427C型嵌入式工业PC机。如图1所示，PC机与PLC控制器之间采用PROFIBUSDP协议进行数据通讯，PC机做从站，PLC控制器做主站。PC机侧配置CP5611网卡，PLC控制器侧配置CP342-5网卡，网卡之间通过PROFIBUSDP总线连接。PC机中安装WINPE操作系统、SIMATICNET6.2、LABVIEW8.6开发软件。PC机侧的网络配置在SIMATICNET6.2软件中完成，PLC侧网络配置在STEP75.3开发软件中完成。在LABVIEW8.6软件中开发主回路控制程序，在STEP75.3软件中开发副回路控制程序。The air knife from FOEN Company in Germany, the coating thickness gauge from THERMO Company in the United States are selected, the S7-300PLC controller from SIEMENS Company is selected as the air knife controller, and the IPC427C embedded industrial PC from SIEMENS Company is selected as the industrial PC. As shown in Figure 1, the PROFIBUSDP protocol is used for data communication between the PC and the PLC controller, the PC is the slave station, and the PLC controller is the master station. The CP5611 network card is configured on the PC side, and the CP342-5 network card is configured on the PLC controller side, and the network cards are connected through the PROFIBUSDP bus. Install WINPE operating system, SIMATICNET6.2, LABVIEW8.6 development software in the PC. The network configuration on the PC side is completed in the SIMATICNET6.2 software, and the network configuration on the PLC side is completed in the STEP75.3 development software. The main loop control program is developed in LABVIEW8.6 software, and the secondary loop control program is developed in STEP75.3 software.
2、如图2所示，系统采用串级控制，主回路控制程序运行在PC机中，副回路控制程序运行在PLC控制器中。控制系统主回路扫描周期1s，副回路扫描周期20ms。2. As shown in Figure 2, the system adopts cascade control, the main loop control program runs in the PC, and the secondary loop control program runs in the PLC controller. The scanning period of the main loop of the control system is 1s, and the scanning period of the secondary loop is 20ms.
3、主回路由气刀间距预设定、前馈闭环控制、反馈闭环控制三部分组成。3. The main circuit is composed of three parts: air knife spacing preset, feed-forward closed-loop control, and feedback closed-loop control.
(1)气刀间距预设定表格：(1) Air knife spacing preset table:
(2)前馈控制模型。根据不同镀层厚度规格，利用最小二乘法建立对象的数学模型：(2) Feedforward control model. According to different coating thickness specifications, the mathematical model of the object is established by the least square method:
W(80)=-0.029P+2.795D+0.229V；W(80)=-0.029P+2.795D+0.229V;
W(100)=-0.285P+5.567D+0.704V；W(100)=-0.285P+5.567D+0.704V;
W(120)=-0.174P+5.672D+0.451V；W(120)=-0.174P+5.672D+0.451V;
W(180)=-0.409P+7.587D+0.780V；W(180)=-0.409P+7.587D+0.780V;
W(220)=-0.148P+5.485D+0.508V；W(220)=-0.148P+5.485D+0.508V;
W(275)=-0.191P+3.181D+1.027V；W(275)=-0.191P+3.181D+1.027V;
其中W-镀层厚度，P-气刀压力，D-气刀间距，V运行速度。Among them, W-coating thickness, P-air knife pressure, D-air knife distance, V running speed.
如图3所示前馈控制模型消除速度扰动的控制效果，当速度变化时前馈控制模型计算的压力设定值进行调整，消除速度波动对镀层厚度的扰动。As shown in Figure 3, the feedforward control model eliminates the control effect of speed disturbance. When the speed changes, the pressure set value calculated by the feedforward control model is adjusted to eliminate the disturbance of the speed fluctuation on the thickness of the coating.
(3)反馈控制回路包括双面平均镀层厚度控制回路和双面偏差镀层厚度控制回路。针对过程的大滞后、非线性、时变特性选用通用型无模型自适应控制器，控制器通过前N个采样值来分析偏差的整个趋势，观察过程的动态特性。通过这种观察利用神经网络技术，根据偏差的历史数据直接计算出下一步控制作用。(3) The feedback control loop includes a double-sided average coating thickness control loop and a double-sided deviation coating thickness control loop. For the large lag, nonlinear and time-varying characteristics of the process, a general-purpose model-free adaptive controller is selected. The controller analyzes the entire trend of the deviation through the first N sampling values and observes the dynamic characteristics of the process. Through this observation, neural network technology is used to directly calculate the next step of control action according to the historical data of the deviation.
双面平均镀层厚度控制回路，当偏差小于3g/m2时，进行微调，控制器参数Kc=0.5，Tc=30s，过程的滞后时间最大300s，最小80s。当镀厚偏差大于3g/m2小于30g/m2时，调节幅度加强，控制器参数选择Kc=0.55，Tc=45s。如图4所示双面平均镀层厚度控制效果，镀层厚度规格为36g/m2，稳态运行过程中通过动态调整气刀压力进行双面平均镀层厚度控制，双面平均镀层厚度偏差控制在4g/m2以内。The double-sided average coating thickness control loop, when the deviation is less than 3g/m 2 , fine-tuning is performed, the controller parameters Kc=0.5, Tc=30s, the lag time of the process is at most 300s and at least 80s. When the plating thickness deviation is greater than 3g/ m2 and less than 30g/ m2 , the adjustment range is strengthened, and the controller parameters are selected as Kc=0.55 and Tc=45s. As shown in Figure 4, the effect of double-sided average coating thickness control, the coating thickness specification is 36g/m 2 , and the double-sided average coating thickness is controlled by dynamically adjusting the air knife pressure during steady-state operation, and the double-sided average coating thickness deviation is controlled at 4g / m2 or less.
双面偏差镀层厚度控制回路，当镀厚偏差小于2g/m2时，进行微调，控制器参数Kc=0.1，Tc=8s,过程的滞后时间最大300s，最小80s。当镀厚偏差大于3g/m2小于30g/m2时，调节幅度加强，控制器参数选择Kc=0。25，Tc=45s。如图5所示双面偏差镀层厚度控制效果，镀层厚度规格为36g/m2，当双面镀层厚度出现较大偏差时，通过调整气刀框架位置进行双面偏差镀层厚度控制，将双面镀层厚度偏差控制在4g/m2以内。Double-sided deviation coating thickness control loop, when the coating thickness deviation is less than 2g /m2, fine-tuning is performed, the controller parameters Kc=0.1, Tc=8s, the lag time of the process is at most 300s, and the minimum is 80s. When the plating thickness deviation is greater than 3g/ m2 and less than 30g/ m2 , the adjustment range is strengthened, and the controller parameters are selected as Kc=0.25, Tc=45s. Figure 5 shows the coating thickness control effect of double-sided deviation. The coating thickness specification is 36g/m 2 . The coating thickness deviation is controlled within 4g/ m2 .
4、副回路包括气刀压力、间距、框架位置闭环控制，如图2所示。4. The auxiliary circuit includes closed-loop control of air knife pressure, spacing, and frame position, as shown in Figure 2.
(1)气刀压力闭环控制回路。回路包括变频电机、压力传感器、PI控制器。通过变频电机驱动气刀风机调节气刀压力，通过控制变频电机转速控制气刀压力。(1) Air knife pressure closed-loop control circuit. The circuit includes frequency conversion motor, pressure sensor and PI controller. The air knife fan is driven by a frequency conversion motor to adjust the pressure of the air knife, and the pressure of the air knife is controlled by controlling the speed of the frequency conversion motor.
(2)气刀间距闭环控制回路。回路包括步进电机，位置传感器，P控制器。通过步进电机启停控制调节气刀间距。(2) Closed-loop control circuit of air knife distance. The loop includes a stepper motor, a position sensor, and a P controller. The distance between the air knives is adjusted through the start and stop control of the stepping motor.
(3)气刀框架位置闭环控制回路。回路包括普通交流电机，位置传感器，P控制器。通过电机启停控制调节气刀框架位置。(3) Air knife frame position closed-loop control circuit. The loop includes a common AC motor, a position sensor, and a P controller. Adjust the position of the air knife frame through the motor start and stop control.
5、镀层厚度控制手动/自动模式无扰动切换。手动模式时主回路不参与控制，副回路气刀压力、间距位置、框架位置设定值由操作工手动给定。气刀间距预设定回路跟随当前手动设定值，前馈控制模型实时计算气刀压力基础设定值，反馈控制中偏差镀层厚度控制回路停止计算，平均镀层厚度控制回路设定值为当前气刀压力手动设定值与前馈控制模型计算的基础设定值之差。当由手动切换到自动模式时，气刀间距位置保持不变，偏差镀层厚度控制回路开始计算，当前气刀压力设定值作为双面平均镀层厚度主回路输出的初始设定值。自动模式切换到手动模式时，锁存主回路前一扫描周期输出的设定值作为副回路的初始设定值，主回路控制切除。5. The manual/automatic mode of coating thickness control can be switched without disturbance. In the manual mode, the main circuit does not participate in the control, and the setting values of air knife pressure, distance position and frame position of the secondary circuit are manually given by the operator. The air knife spacing preset loop follows the current manual setting value, the feedforward control model calculates the basic set value of the air knife pressure in real time, the deviation coating thickness control loop stops calculation during feedback control, and the average coating thickness control loop set value is the current air knife pressure. The difference between the manually set value of the knife pressure and the base set value calculated by the feedforward control model. When switching from manual to automatic mode, the air knife spacing position remains unchanged, the deviation coating thickness control loop starts to calculate, and the current air knife pressure setting value is used as the initial setting value output by the main loop of the double-sided average coating thickness. When the automatic mode is switched to the manual mode, the set value output by the main loop in the previous scanning cycle is latched as the initial set value of the secondary loop, and the main loop control is cut off.
6、换卷过程镀层厚度控制。换卷过程中前馈控制模型始终进行计算。如果换卷过程镀层厚度规格不变，当焊缝到达气刀时将当前气刀间距设定值和反馈控制器输出值锁存，直到焊缝经过测厚仪时锁存解除。如果换卷过程镀层厚度规格改变，当焊缝到达气刀时首先将反馈控制器输出清零，然后通过查表选择气刀间距预设定值进行气刀间距调整，当焊缝进过测厚仪时反馈控制器开始计算气刀压力附加设定值。6. Coating thickness control during coil change. The feed-forward control model is always calculated during lap change. If the thickness specification of the coating remains unchanged during the coil change process, when the weld seam reaches the air knife, the current set value of the air knife distance and the output value of the feedback controller are latched until the weld seam passes through the thickness gauge and the latch is released. If the thickness specification of the coating changes during coil change, when the weld seam reaches the air knife, first clear the output of the feedback controller, and then select the preset value of the air knife spacing by looking up the table to adjust the air knife spacing. The instrument time feedback controller starts to calculate the additional set value of the air knife pressure.
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