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H型钢制作矫直机设计含6张CAD图,型钢,制作,矫直机,设计,CAD
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外文资料AUTOMATING THE CONTROL OF MODERN EQUIPMENT FORSTRAIGHTENING FLAT-ROLLED PRODUCTS The company Severstal completed the successful introduction of new in-line plate-straightening machines (PSMs) on its 2800 and 5000 mills in August 2003 1, 2, 3. The main design featuresof the machines are as follows: each machine is equipped with hydraulic hold-down mechanisms (to improve the dynamics and accuracy of the machine adjustments and more reliablymaintain a constant gap); the machines have mechanisms to individually adjust each work roller with theaid of hydraulicylinders (this broadens the range of straightening regimes that can be realized by providing a measure of control over the change in the curvature of the plate); each work roller is provided with its own adjustable drive (to eliminate rigidkinematic constraints between the spindles); the system of rollers of the PSM is enclosed in cassettes (to facilitate repairs andreduce roller replacement costs); the PSM has a system that can be used to adjust the machine from a nine-rollerstraightening scheme to a five- roller scheme in which the distance between the rollers is doubled (this is done to widen the range of plate thick-nesses that the machine can accomodate). Thus, the new straightening machine is a sophisticated multi-function system of mechanisms th-at includes a wide range of hydraulically and electrically driven components controlled by digital and analog signals. The entire complex of PSM mechanisms can be divided into two functional groups: the main group, which includes the mechanisms that partici-pate directly in the straightening operation (the hold-down mechanisms, the mechanisms that individually adjust the rollers,the mechanisms that adjust the components for different straightening regimes, the mechanism that moves the top roller of the feeder, and the main drive); the auxiliary group (which includes the cassette replacement mechanism, the spindle-lock-ing mechanism, and the equipment that cools the system of rollers). Although the PSM has a large number of mechanisms,the use of modern hydraulic and electric drives has made it possible to almost completely automate the main and auxiliary operations performed on the PSM and the units that operate with it. Described below are the features and the automatic control systems for the most important mechanisms of the plate-straightening machine.The operating regimes of those mechanisms are also discussed.The hydraulic hold-down mechanisms (HHMs) of the sheet-straightening machine function in two main regimes:the adjustment regime;the regime in which the specified positions are maintained.There are certain requirements for the control system and certain efficiency criteria for each regime. In the adjustment regime, the control system for the hydraulic hold-down mechanisms must do the following: synchronize the movements of the hydraulic cylinders and keep the angular deeflection within prescribed limits; maximize speed in adjusting the machine for a new plate size; maintain a high degree of accuracy in positioning the mechanisms;The control system has the following requirements when operating in the maintenance regime: stabilize the coordinates of the top cassette and the top roller of the feeder with a high degree of accuracy; minimize the time needed to return the equipment to the prescribed coordinates when deviations occur (such as due to the force exerted by a plate being straightened). Need for synchronization. Experience in operating the plate-straightening machine in plate shop No. 3 at Severstal has shown that the most problematic factor in adjusting the machineis the nonuniformity of the forces applied to the hydraulic cylinders. This nonuniformity is due to the asymmetric distribution of the masses of the moving parts of the PSM (in particular, the effect of the weight of the spindle assembly). Displacement of the “hydraulic zero point” relative to the “electrical zero point” in the servo valves is also a contributing factor.The latter reason is more significant, the smaller the volume of the hydraulic cylinder.Thus, the HHM of the top roller of the feeder is the most sensitive to drift of the zero point. There are also other factors that affect the dynamism,simultaneousness,and synchronism of the operation of the hold-down mechanisms: differentiation of the frictional forces on parts of the hydraulic cylinders due to different combinations of deviations in the dimensions of the mated parts, despite the narrow tolerances; differences in the “springing” characteristics and the indices characterizing the inertia of the hydraulic supply channels (due to differences in the lengths of the pipes leading from the servo valves to the hydraulic cylinders). Thus, since the PSM is not equipped with devices to mechanically synchronize the operation ofthe cylinders, the ransmission of signals of the same amplitude to the inputs of the servo valves inevitably results in a speed difference that can seriously damage the mechanisms. To minimize and eliminate the effects of the above-mentioned factors, we developed an algorithm for electrical synchronization of the hold-down mechanisms. The HHM of the top cassette, composed of four hold-down cylinders and four balancing cylinders, is designed to ensure mobile adjustment of the machine to set the required size of straightening gap (in accordance with the thickness of the plate) and maintain that gap with a specified accuracy in the presence and absence of a load on the housings from the straightening force. The hydraulic system of the hold-down mechanism is designed in such a way that only one chamber of the hydraulic cylinders is used as the working chamber.The second chamber is always connected to the discharge channel.The top cassette is lowered when the balancing forces are overcome by the hold-down cylinders.The cassette is raised only by the action of the balancing cylinders.This arrangement has made it possible to eliminate gaps in the positioning of the equipment. The HHM of the top roller of the feeder consists of two hydraulic cylinders. Hydraulic fluid is fed into the plunger chamber when the roller is to be lowered and is fed into the rodchamber when it is to be raised. Control Principles. Individual circuits have been provided (Fig.1) to control the hydraulic cylinders of the hold-down mechanisms.The control signal (Xctl) sent to the input of the servo valve is formed by a proportional-integral (PI) controller (to improve the sensitivity of the system, we chose to use valves with “zero” overlap).The signal sent to the input of the controller (the error signal Xerr) is formed as the difference between the control-point signal for position (Xcpt) and the feedback signal (Xf.b).The latter signal is received from the linear displacement gage (G) of the given hydraulic cylinder. The gages of the HHM for the top cassette are built into the balancing hydraulic cylinders (HCs).The cylinders are installed in such a way that their movements can be considered to be equalto the displacements of the corresponding cylinder rods, with allowance for certain coefficients.The gages in the HHM for the top roller of the feeder are incorporated directly into the hold-down cylinders. The integral part of the controller is activated only during the final adjustment stage and duringstabilization of the prescribed coordinate.When the displacements exceed a certain threshold value, the functions of the PI controller are taken over by a proportional (P) controller with the transfer function W(s) = k.Thus, Xctl(t) = kXerr(t). When there are significant differences between the displacements of the working rollers,the difference (error)between the control point and the feedback signal from the linear displacement gage reaches values great enough so that the output signal which controls the operation of the servo valve reaches the saturation zone.In this case, further regulation of the displacement rate and,thus synchronization of the movements of the cylinders becomes impossible as long as the error exceeds the value at which Xctl is greater than the boundary value for the saturation zone (Xsat).The limiting errorthe largest error for which Xctldoes not reach saturationis inversely proportional to the gain of the controller k: Xerr Xsat/ k. Solving the given problem by decreasing k leads to a loss of speed in the adjustment of the PSM and a decrease in control accuracy during the straightening operation.Thus, to keep the control signal from reaching the saturation zone when there are substantial displacements, the system was designed so that the input of the controller is fed not the actual required value (Xrq) but an increment (X) of a magnitude such that the condition kX Xsat is satisfied.The control point is increased by the amount X after the position of the cylinder has been changed by the amount corresponding to the increment having the largest lag relative to the cylinders direction of motion. The adjustment of the control point is continued until the difference between the required value and the actual position of the mechanism becomes less than the increment:Xrq-xf.bx. Use of the principle of a stepped increase in the control point makes it possible synchronize the movements of the cylinders and set the control point with a high degree of accuracy for almost any ideal repetition factor. Mechanisms for Individual Adjustment of the Working Rollers.The plate-straightening machine is designed so that each working roller can be moved vertically, which is done by means of a hydraulic cylinder acting in concert with a V-belt drive.The cylinders are supplied with power from servo valves operated with proportional control.A linear displacement gage is built into each cylinder to obtain a feedback signal on the position of the roller.Since these gages are actually transmiting information on the position of the cylinder rods rather than the working rollers themselves, the following conversion is performed to obtain the rollers coordinates:Xrol= kredXf.b, Where kred is the gear ratio of the drive;Xf.b is the position of the cylinder rod measured by the linear displacement transducers. Thus, a position feedback circuit is provided to control the position of each working roller. Figure 1 presents a diagram of one of the circuits. The control signals are generated by means of the PI controllere, which has made it possible to achieve a high degree of accuracy in adjusting the system without sacrificing speed.The individual drive of the rollers. The above-described design is based on the use of individual ac drives with motors of different powers fed from frequency converters. Each individual drive offers the following advantages over a group drive: greater reliability thanks to the absence of additional loads on the components of the mechanisms due to differences between the linear velocities of the working rollers and the speed of the plate; he possibility that the machine could continue to operate if one or even several drives malfunction;in this case,the corresponding rollers would be removed from the straightening zone; the possibility that the linear velocities of the rollers could be individually corrected in accordance with the actual speed of the plate;such a correction could be made either as a preliminary measure (on the basis of measured and calculated values) or during the straightening operation (on the basis of the data obtained from the frequency converters, which employ artificial intelligence). The main drive of the straightening machine rotates nine straightening rollers and two housing rollers.This drive must be highly reliable in operation, since the fact that the PSM is installed in the mill line means that sizable production losses can be incurred if the drive fails to work properly even for a short period of time. The requirements that must be satisfied by the drive are determined by the operational and design features of the machine as a whole: the plate being straightened must create a rigid kinematic coupling between the straightening rollers, the rollers of the housing, and the adjacent sections of the roller conveyors; the plate should undergo elongation during the straightening operation as a result of plastic deformation, with the increments in length being different on each working roller due to the differentiation of the bending radii;this situation leads to a nonuniform increase in the speed of the plate as it moves toward the end of the PSM; it must be possible to use working rollers of different diameters (this being done, for example, due to nonuniform wear or regrinding); the loads on the rollers should be differentiated in accordance with the chosen straightening regime; reverse straightening should be possible. In light of the above factors and the actual operating regimes of the plate-straightening machine being discussed here, the following requirements can be established for the electric drive: regulation of speed within broad limits, including startup of the motors under load; operation in the reverse regime; a rigid characteristic = f(M); high degree of accuracy in maintaining the prescribed speed; fully synchronous operation. The element base. The drive of the rollers was built with the use of asynchronous three-phasemotors having a short-circuit rotor.The motors were designed by the German company VEM.Theycan continue to function under severe overloads and are reliable in operation. The motors are controlled by SIMOVERT frequency converters made by the German firm Siemens.Their modular design facilitates maintenance and repair, and the presence of a built-in microprocessor block makes it possible to execute most of the functions involved in controlling the operation of the drive (maintain the prescribed speed with a high degree of stability, recalculate the frequency of rotation in accordance with the actual diameters of the rollers, diagnose the condition of the drive, control the drives operation, and exchange information on the PROFIBUS network). Motors of different powers are used in the system because of the differentiated distribution of the moments between the working rollers.Using different motors has made it possible to significantly reduce the cost of the electrical equipment and improve the performance characteristics of the machine as a whole. The machine has three main operating regimes: the working regime (semi-automatic and automatic), the transport regime, and the cassette replacement regime. Figure 2 shows a block diagram of the operations connected with realization of the working regime.In the semi-automatic variant of this regime, the operator controls the PSM from a control panel.In this case, the operator can do the following: choose the straightening regime from a database;correct the chosen regime;adjust the regime manually, which requires that the operator indicate the desired position of the bottom cassette (for five- or nine-roll straightening);adjust the gap between the top and bottom cassettes; set the coordinates for individual adjustment of the working rollers; choose the straightening speed and direction;generate a command to begin adjusting the machine to the specified regime. Fig. 2. Block diagram of the working regime of the PSM. The machine is adjusted to the chosen regime automatically.After the adjustment is completed, a signal is sent to the control panel indicating that the coordinates of the mechanisms have beenchanged and that the rollers have reached their prescribed working speeds. In the automatic variant of the working regime, the plate-straigthening machine isadjusted on the basis of data sent through a data network from a higher-level system. These data include the following information: the thickness of the plate being straightened; the group of steels (information on the properties of the material); the temperature of the plate at the inlet to the PSM. The PSM is adjusted in several stages: preliminary adjustment based on the plate thickness and steel group, for cold-rolled plates (t = 20C); further adjustment on the basis of data obtained from a pyrometer installed roughly 50m from the PSM; final adjustment on the basis of data obtained from a pyrometer installed at theentrance to the machine. In the automatic variant, control over the roller conveyors adjacent to the machine is switched over to the control system of the PSM as the next plate approaches the machine.In this case, the plate cannot enter the working zone of the machine until the adjustment is completed. If it is necessary to pass a plate through the machine without straightening it, the machine is changed over to the transport regime.In this case, the top crossarm and the cassette are elevated a prescribed amount and the speed of the rollers is changed so that it is equal to the speed of the adjacent roller conveyors. The cassette replacement regime is used in the event of breakage of a roller or when it is necessary to regrind the working and backup rollers.In this case, the operator can control the operation of the auxiliary mechanisms:the spindle-locking mechanism, the roll-out cart, the mechanism that locks the bottom cassette and the cart in position, and the hydraulic cylinder that moves the cart. The mechanisms are fixed in position by means of noncontact transducers. PSM Control System. Control of the plate-straightening machine required the development of a powerful, high-capacity system that could provide the desired control accuracy in combination with rapid operation. The control system that was created is divided into two levels: the base level, and an upper level.The diagnostic system was created as a separate system.A second controller was also provided, to control the pump station of the PSM.The base level of the control system employs a SIMATIC S7 industrial programmable controller, while the upper level and the diagnostic system were built on the basis of standard The different elements of the control system are linked by two loops of a PROFIBUS network (Fig.3).The first loop functions as the communications link between the controller, the upper-level computer, the diagnostics station, and the pump-station controller.The second loop links the PSM controller with the functional elements of the system (the frequency converters, linear displacement gages, and remote input/output module). The functions of the control system were divided between the base level and the upper level on the basis of the following principle: the base level was assigned all of the operations that involve receiving data from the sensors installed on the mechanisms, obtaining information from the automated process control system on the plate being straightened, and generating and transmitting control signals for the executive mechanisms (actuators); the upper level was assigned the functions of archiving the control points and monitoring the operation of the control panel. The following specific functions are performed by the base level of the automation system: obtaining the assigned straightening parameters (roller speeds, the coordinates of the top crossarm, and the coordinates of the rollers relative to the crossarm) from the upper-level system; processing the parameters and sending corresponding control signals to the actuators; Obtaining information from the sensors installed on the mechanisms to determinewhether or not the PSM is properly set and ready for the straightening operation; obtaining information from the feedback transducers installed on the mechanisms tocalculate the control actions; analyzing the readings of the sensors to determine the accuracy of the data; exchanging data with the pump-battery station (PBS) of the PSM and transmitting the stations operating parameters to the upper-level system for display; receiving signals from the upper-level system for manual control of the machine and the PBS; obtaining initial data from the upper-level system for automatic correction and transmission of the data in order to make the appropriate adjustments.The functions of the upper-level automation system are as follows: entering data on the straightening regimes for subsequent selection of the regime and recording that information in a database; manually choosing the straightening regime from the database for the corresponding plate (this is done by the operator); automatically choosing the straightening regime from the database on the basis of information obtained from the upper-level system; manually controlling the machine in the straightening and cassette-replacement regimes; indicating the positions of the mechanisms based on readings from the sensors and indicating the presence of a plate in the working zone of the PSM; indicating the temperature of the plate measured by the pyrometer; visually representing the straightening regimes and machine adjustments; visually representing the state of the machines mechanisms and the PBS for diagnostic purposes. Remote input-output module ET200 is used to supply power to the unregulated drives.The cabinet containing the relays and contacts for these drives is located a considerable distance from the controller.Use of the module has made it possible to significantly shorten the connecting cables.Diagnostic System. The heavy concentration of electrical and hydraulic equipment included as part of the PSMequipment which is located an appreciable distance from the machine itself and is often in hard-to-reach placesmakes it more difficult to service the machine and locate the source of problems.To facilitate maintenance of the PSM and shorten repair time, it was necessary to build an advanced diagnostic system. The system is based on an industrial computer installed at the control post.It diagnoses the state of various mechanisms of the PSM, as well as its hydraulic and electrical equipment.The system can be used to evaluate the condition of the automatic switches, the temperature sensors of the motors, the linear displacement gages, terminals of the local PROFIBUS network, the currents, speeds, and direction of rotation of the motors, and other equipment and parameters. The diagnostic system can also be used to establish the operating protocol of the PSM.Its archives contains data on the time and types of errors and equipment failures that occur, the coordinates of the mechanisms, motor currents and speeds, and other information. To make the control system more reliable, the software and hardware of the diagnostics station are identical to the corresponding components of the control systems upper level.When problems occur with the operation of the control computer, the PSMcontrol functions can be transferred to the computer of the diagnostic system.Conclusions.The NKMZ has worked with its original partners in the Commonwealth of Independent States (CIS) to successfully introduce plate-straightening machines equipped with a modern automated control system. Use of the machines makes it possible to minimize and almost completely eliminate the dependence of the quality of thefinished plates on the skill of the machine operator. The control system, together with its convenient user interface,allows even personnel with no special training to quickly master the operation of the machine. The production of high-quality products is assured as a result of the exact movements of the machines mechanisms and the accuracy with which their positions are maintained, which owes to the use of precision equipment with proportional control and special controlalgorithms. In addition, the machine is equipped with a sophisticated diagnostic system which also records its key operating parameters.The availability of the system facilitates maintenance and repair of the machines many complex components. 中文译文：现代化矫直轧制薄品设备的自动化控制 谢韦尔钢铁公司在2003年8月成功完成了新引进的规格为28005000米尔的直线式钢板矫直机（平台相关模型）。机器的主要设计特点如下： 每台机器配备液压紧固装置(用于改善机器的动力学性能和调整的准确性以及更可靠地保持恒定的间隙) 每台机器都有能在液压缸的辅助下分别调节每根工作辊的机构(通过提供一种控制钢板的曲率变化的方法来实现拓宽矫直范围的目的)。 每个工作辊具有它自己的调节驱动(去除主轴之间的刚性运动学制约） 该系统平台相关模型的辊轴是封装在封闭箱（录音带）中的(便于维修,降低替换辊的成本) 这个模型有一个系统,它可用于调整机器从九辊矫直方案转变为五辊矫直方案，过程辊间的距离增加了一倍(这是为了扩大机器对板厚度的可允许范围)。因此,新的矫直机是一个多功能、复杂的机器,其包括一个可由数字和模拟信号控制的宽范围、电驱动元件的液压组件。整个复杂的机构可以分为两个功能机体：主要的机体,包括直接参与矫直操作的机构(其夹紧装置能独立适应轧辊,调整组件以适应不同的矫直要求,可移动支线和主传动装置的上辊) ；辅助装置(包括盒式替代装置、主轴锁定机构、辊轴支架设备冷却系统)。虽然平台相关模型有大量的机制,运用现代液压和电气驱动，能够在平台相关模型和其运转机构上几乎完全的实现对主要和辅助机构的自动化控制操作。 下面描述的是薄板矫直机的特点以及自动控制系统的最重要的机理，同时对操作机理也进行了探讨。薄板矫直机的液压紧固机构(HHMs)功能在于两大系统:调整系统；指定位置的维护系统。对控制系统和某些有效条件系统存在一定的要求。 在液压紧固机构的调整系统、控制系统,必须做到以下几点： 液压缸的同步运动保持，角偏转到规定的限量以内； 为适应新板的尺寸的最大调整速度； 保持高的定位精度的机制； 该控制系统在维护系统操作时具有以下要求： 使封闭箱的（录音带）附件保持稳定，同时保证给料机的上辊具有较高的准确性； 当偏差出现时，最大限度地减少设备返还到约定坐标所需的时间(例如金属板由于被矫直时而显 现出的弹力)。 同步需求。根据谢韦尔钢铁集团3号金属板矫直机组得出的操作经验,调整机器时最不确定的因素是因为应用液压缸儿产生的不均匀力。这种非均匀性是由平台模型上大部分活动部件不对称分布所引起的（特别是主轴装配时的偏重效应）。伺服阀的“液压零点”与“电气零点”的相对位移也是一个因素。液压缸的体积越小后者越重要。因此，给料机上辊的HHM的零点漂移是最敏感的。 也有其他因素的影响,同时性, 紧固机制的同步运行： 液压缸上部分区域的摩擦力的差别源于成对零件的规模大小的组合差异，即使偏差非常的小； “弹起”差异特征和液压供应渠道的惯性表征指标(由于液压缸的伺服阀不同长度管的入口)。 因此,即使模型上没有配置机械地保持液压缸操作同步的装置, 伺服阀的相同振幅信号的传输的输入不可避免导致一个严重危害机器的速差。 对降低及消除上述因素的影响,研制出一种对紧固机制进行电气同步的算法。 包括四个紧固缸、四个平衡缸的封闭箱顶部的HHM,是为保证机器的灵活的调整设定所需尺寸的矫直差(按照板的厚度),并通过现有的准确性和遮蔽物上矫直力的符合缺乏来维持这个精度范围。液压系统的紧固机制设计是这样一种方式,只有一室的液压缸,是用来作为工作室。第二室总是与排泄通道相连。平衡力量被紧固气缸克服时封闭箱降低顶端的。只有在气缸平衡时封闭箱才提起。这样的布置可以消除精度范围在设备上的影响。 顶部的HHM的辊的支线由两个液压缸组成。当辊被提升的同时，辊降低和油液输入杆腔，液柱塞腔被注入液油。 控制原则。特有电路如图所示(图1),来控紧固机制的液压缸。伺服阀输入端的控制信号（Xctl）是由一个比例-积分(PI)控制器传递的(为了提高灵系统的敏度,我们选择了用瓣膜,以“零”触发)。输入信号（错误信号Xerr）发送到控制器的输入端后形成位置（Xcpt）和反馈信号的要点控制信号（Xf.b），后续信号是从所给液压缸的直线位移轨距（G）接收的。 密封箱顶部的HHM的标定测量头组成了平衡液压缸(HCs)。气瓶是安装了这样一种方式,他们的动作可以被认为是等于位移相应圆柱棒、与津贴为某些系数。支线上辊的HHM的测量头组成了紧固气瓶。该控制器的不可分割的组成部分,仅在最后被激活时调整阶段和稳定规定的坐标。当位移超过一定阈值,PI控制器的功能是被一个比例(P)控制器的传递函数所代替的W(s)= k。因此,Xctl(t)= kXerr(t)。 当有工作中的辊子有非常显著的差异时,这其中之间的关键控制点和反馈信号的区别(误差)从直线位测量达到足够大,这样值输出信号控制伺服阀的操作达到饱和区。在这种情况下,进一步位移、速度和同步动作的规定,这样当误差超过范围时气缸的同步移动变得不可能，这时Xctl大于饱和区的边值问题(Xsat)。 通过减少k来解决特定的问题导致了在调整PSM时的速度损失和矫直机的操作中控制精度的降低。因此,为了保持控制信号到达饱和区当有大的位移、整个系统的设计，这样的输入端控制器并不是实际的所需值（Xrq),但增量(?X)是巨大的，k ?X Xsat 这样的状况是令人满意的。液压缸的位置变化后，控制点的增加取决于?X的大小，其与相对于圆柱的运动方向相应的有最大的滞后量有关。调整的关键控制点维持现状，直到所需要求和装置的实际位置之间的差异小于其增量：Xrq Xf.b X。然后控制器的输入适应其增值Xcpt，相当于调整要求：Xcpt= Xrq。调整如此完成。 使用的原则是一步几乎对所有的理想重复的因素而言，增加控制点使人们有可能同步运动的汽缸和设置的关键控制点以高度的准确性。独特的调整机制工作辊。平板矫直机如此设计通过借助于V-belt驱动液压缸动作来实现每个工作辊可以移动垂直。通过操作与比例伺服阀的控制来提供液压缸的动力。线性位移测量器设置在每一个液压缸上获得辊的位置反馈信号。由于这些测量头实际上是传递着液压拉杆的位置信息而不是工作辊本身，在接下来的转换中来得到坐标：kred驱使齿轮d动比;Xf.b是通过直线位移传感器测量的柱杆位置。 因此,位置反馈电路反应了各项工作辊的姿态控制。图1为电路图。 控制信号产生采用PI控制器,它使得人们有可能达到了高度的调节系统的预测精度而不损失速度。 独立驱动的辊子。这四种设计是基于使用独立驱动的交流电机，其分别采用了不同动力反馈的变频
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