板形自动控制在热连轧中的应用

莱钢1500热连轧生产线的板形自动控制系统是国内自主研发的板形控制系统,它包括板预设定形、板形的PID调节、弯辊力的前馈控制、凸度仪的反馈控制、窜辊的闭环调节、平坦度的反馈控制、板形与板厚的解耦控制等多种控制于一体。主要介绍弯辊力前馈、凸度反馈和平坦度反馈3个模型在实际轧钢过程中的应用。     

冷轧机板形控制系统弯辊力预设定模型开发

针对某公司六辊冷轧机,采用影响函数法建立了辊系变形计算模型并开发了相应的计算程序。利用所建辊系变形模型结合轧机的板形控制策略,建立了针对轧机的理论和在线两种弯辊力预设定模型。实例计算表明,所开发模型精度符合实际要求,可用于生产实际,为提高轧机板形控制预设定精度,改善轧机产品的板形质量提供了理论依据。     

热连轧机弯辊控制系统的改造与实践

1　引言热连轧机的弯辊控制系统由工业过程控制机及相应的检测元件与液压动力机构构成一个闭环控制系统 ,进行弯辊力的控制 ,其中液压动力机构采用电液比例减压阀作为控制动力元件驱动弯辊缸。在满足系统动态响应的前提下 ,比例控制系统具有对油液过滤精度要求不高、造价低等优点 ,但由于比例减压阀固有的死区特性 ,使系统无法实现对较小弯辊力的控制 ,制约了轧制过程中对带钢板形的控制 ,严重影响了产品的质量。2　系统分析与对策依据系统构成及液压控制系统原理 ,弯辊控制系统的控制模型可简化为图 1所示的结构。其中 ,原系统中的压力反馈…     

连退平整机组带钢过焊缝过程中板形控制技术研究

针对连退平整机组带钢过焊缝过程中板形波动的问题,充分考虑连退平整机组的设备与工艺特点,以中间辊弯辊力对轧制压力进行补偿,以工作辊弯辊力对前后张力进行补偿,建立了板形控制模型。通过理论模型与现场试验相配合,实现了中间辊弯辊力和工作辊弯辊力的动态补偿,最大程度地减少了板形的波动幅度。     

冷连轧设定控制系统综合优化研究

基于现阶段冷轧板形精度要求的提高、板形控制技术的发展与智能控制技术的进步,在传统冷连轧负荷分配研究基础上,提出板形板厚张力设定控制系统综合优化计算方法。对板厚、张力进行兼顾板形偏差最小、弯辊裕量最优及负荷平衡的多目标优化设计,对工作辊弯辊、中间辊弯辊以沿带钢全宽板形偏差最小为目标进行优化设计。优化计算采用具有良好全局和局部寻优能力的三种群粒子群差分进化算法(Three-populations particle swarm optimization and differential evolution algorithm,Thr_PSODE)。现场应用结果表明,通过设定控制系统综合优化对轧制规程、张力制度以及各板形调控手段的优化配置,在兼顾多个优化目标的同时充分挖掘轧机的板形调控能力,实现了对复杂模态的高次板形缺陷的有效控制,具有重要的研究价值与应用前景。     

五机架四辊冷连轧机板形参数综合设定技术

经过大量的现场试验与理论研究,结合五机架四辊冷连轧机组的设备与工艺特点,改变传统技术中对1机架～5机架5个部分板形参数单独考虑的设定方法,以成品板形质量最佳为优化目标函数,同时将各个部分板形参数的相对余量均匀作为约束条件,利用Powell优化方法对板形参数进行综合优化设定,不但可以提高五机架四辊冷连轧机组弯辊对板形的控制能力,充分发挥弯辊的作用提高成品的板形质量,而且可以提高弯辊缸的使用寿命,给企业带来经济效益,具有进一步推广应用的价值.     

小型四辊轧机工作辊水平位移对板形的影响

小型四辊轧机由于工作辊长径比较大且辊径较小而造成工作辊沿轧制方向很容易出现水平位移现象,常规四辊轧机板形计算模型不能满足出口板形的准确计算与预测,为此,充分结合小型四辊轧机的设备与工艺特点,建立了四辊轧机考虑工作辊水平位移时的板形模型;通过板形对比说明了该模型计算结果的准确性。在此基础上,具体分析了工作辊水平位移产生的规律以及在考虑工作辊水平位移时弯辊力对板形控制的影响,并将该模型应用到某钢厂650可逆四辊轧机机组,开发了650可逆四辊轧机工作辊水平位移对板形影响分析软件,有效地解决了以往板形计算误差大的问题,实现了对出口板形的准确计算与预测,大大提高了板形控制精度。     

辊锻设备阀控缸系统的仿真研究

辊轧机板形控制的核心是对辊缝形状的控制,目前广泛采用的控制方法是弯辊阀控缸系统,该方法依靠辊端液压缸产生弯辊力改善板形,弯辊力的动态特性对板形有较大的影响,为了提高板形成形质量,针对四辊轧机建立弯辊阀控缸系统的理论模型,通过MATLAB软件Simulink模块进行仿真研究,分析了弯辊压力在阶跃信号和正弦信号下的动态响应特性指标,分析了主要设计参数对动态特性的影响,并进行了系统辨识试验,通过系统辨识和仿真结果对比,验证了理论模型的正确性,分析了伺服阀固有频率和液压缸等效面积参数对系统动态性能的影响。建立的理论模型和仿真方法可为弯辊阀控缸系统的设计提供理论依据,也可为现有系统优化参数提供参考。     

弯辊力对Q345R/316L不锈钢复合板热轧成形影响研究

针对Q345R/316L不锈钢复合板真空热轧过程中弯辊力预设定问题,采用非线性有限元仿真软件MSC.Marc,建立不锈钢复合板轧制过程三维热-力耦合有限元模型,分别设定模型弯辊力为0 kN、300 kN、500 kN、800 kN四种边界条件,通过数值模拟研究了不同弯辊力作用下复合板宽度方向上的基板压下量、辊系弯曲变形以及半有载辊缝分布规律。分析了在不同弯辊力作用下界面应力应变的分布规律,根据界面结合状态判定条件,设定最佳弯辊力。结果表明:无弯辊力时板形呈现中部高边部低变化趋势,施加弯辊力时板形有了明显改善,并得出弯辊力最佳设定值为500 kN;在总变形量不变的条件下,随着弯辊力的增加,会促进基层和复层金属的变形,应力应变分布均匀,变形协调同性好,有利于复合板界面的结合。     

基于自适应遗传算法的电液弯辊模糊控制系统

为了提高板形内环的执行效率,改善带钢板形质量,针对某300 mm四辊可逆单机架轧机,设计了基于自适应遗传算法优化的电液弯辊模糊控制系统．电液弯辊系统是典型的非线性系统,在考虑非线性因素后建立数学模型,采用最优保存的自适应遗传算法全面优化模糊控制器的量化因子、比例因子、积分因子、隶属函数的参数和控制规则．仿真和实验结果表明优化后的模糊控制明显较优化后的常规PID控制具有更强的鲁棒性、更好的动态品质和稳态精度,为进一步提高板形质量奠定了基础．     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.