Modeling for driving systems of four-high rolling mill

A modeling method for driving systems of four high rolling mill was put forward in order to analyze the origin of rolling mill’s chatter that brings about light and shade streaks on the surface of steel strip from aspect of electromechanical coupling. The process and steps of modeling method was introduced by means of an example. The correctness of the model and the feasibility of the modeling method were verified in simulation experiment.

Analysis and Control over Noises in Main Driving System of XK-736-type NC Miller

Some concrete methods are suggested in the article to control noises in main driving system of XK-736-type NC miller by analyzing working conditions of gears in the main driving system and bearings in the spindle gearshift system. Without changing the original design, noises are reduced ideally by modifying gear top, and by controlling the profile error ; the central distance of meshing gear, the quality of the inner and outer rings of bearings ; and the fit accuracy among bearing, hole and axis. The results may provide a reference for diagnosing and maintaining in future use.

Optimal Design of a Main Driving Mechanism for Servo Punch Press Based on Performance Atlases

The servomotor drive turret punch press is attracting more attentions and being developed more intensively due to the advantages of high speed,high accuracy,high flexibility,high productivity,low noise,cleaning and energy saving.To effectively improve the performance and lower the cost,it is necessary to develop new mechanisms and establish corresponding optimal design method with uniform performance indices.A new patented main driving mechanism and a new optimal design method are proposed.In the optimal design,the performance indices,i.e.,the local motion/force transmission indices ITI,OTI,good transmission workspace good transmission workspace(GTW) and the global transmission indices GTIs are defined.The non-dimensional normalization method is used to get all feasible solutions in dimensional synthesis.Thereafter,the performance atlases,which can present all possible design solutions,are depicted.As a result,the feasible solution of the mechanism with good motion/force transmission performance is obtained.And the solution can be flexibly adjusted by designer according to the practical design requirements.The proposed mechanism is original,and the presented design method provides a feasible solution to the optimal design of the main driving mechanism for servo punch press.

The development of real time data driving multi-axis linkage and synergic movement control system of 3D variable cross-section roll forming machine

The three dimensional variable cross-section roll forming is a kind of new metal forming technology which combines large forming force,multi-axis linkage movement and space synergic movement,and the sequential synergic movement of the ganged roller group is used to complete the metal sheet forming according to the shape of the complicated and variable forming part data.The control system should meet the demands of quick response to the test requirements of the product part.A new kind of real time data driving multi-axis linkage and synergic movement control strategy of 3D roll forming is put forward in the paper.In the new control strategy,the forming data are automatically generated according to the shape of the parts,and the multi-axis linkage movement together with cooperative motion among the six stands of the 3D roll forming machine is driven by the real-time information,and the control nodes are also driven by the forming data.The new control strategy is applied to a 48axis 3D roll forming machine developed by our research center,and the control servo period is less than 10ms.A forming experiment of variable cross section part is carried out,and the forming precision is better than±0.5mm by the control strategy.The result of the experiment proves that the control strategy has significant potentiality for the development of 3D roll forming production line with large scale,multi-axis ganged and synergic movement.

Torsional self-excited vibration of rolling mill

The roller’s torsional self excited vibration caused by roller stick slip, and its influence on strip surface quality have been studied. Based on analysis of roller working surface stick slip, roller rotation dynamics equations have been established. The nonlinear sliding frictional resistance has been linearized, and dynamics equations have been solved according to the characteristics of stick and slip between roller and strip. The results show that: 1) with decreasing stick time t 1, torsional vibration wave pattern gradually transforms from serration into sinusoid, and frictional self excited vibration can cover all frequency components which are lower than that of free vibration; 2) stick time t 1 is directly proportional to torque increment Δ M R , and is inversely proportional to live shaft stiffness K and drive shaft rotational velocity ω ; 3) when slip time t 2 is basically steady, the longer the stick time, the larger the energy that system absorbs and discharges. As the slip time is a constant, it easily arouses strip surface shear impact and surface streaks.

SINAMICS—the high efficiency drive technology for rolling mills

In the Metals Industry,interruption-free processes to produce high-quality end products are a prerequisite. The main drives together with the mill stands play a key role in the success of rolling mills.The crucial demands placed on the drive system are:high-dynamic performance of drive and its control system,ability to handle the process related overloads,smooth running,high availability,high efficiency,easy serviceability and ability to integrate seamlessly with the automation systems.With numerous reference installations and many years of experience Siemens VAI has the wider expertise and the portfolio to provide the right drive for every application. This paper examines the latest innovation,SINAMICS drive technology,for both new drive applications as well as for modernizing the existing drives in rolling mill applications like hot strips mills,plate mills,cold rolling mills,and long rolling mills.

Tier Ⅲ and Ⅳ cities Will Be the Main Driving Forces for Future E-business

Recently,the China E-Business Research Center(100EC.CN)released the'2015 Monitoring Report of China E-business Market'.The report says that the China E-business transaction volume amounted to 18.3 trillion yuan in 2015,up by 36.5%from a year ago,and marking an increase of 5.1 percentage points in growth rate.Meanwhile,the B2B E-business trade value totaled 13.9 trillion yuan,up

Extended-state-observer-based robust torsional vibration suppression for rolling mill main drive system with input saturation

A robust torsional vibration suppression strategy is proposed for the main drive system of the rolling mill subject to uncertainties,disturbances and input saturation.With given model information incorporated into observer design,an extended state observer that relies only on roller speed measurements is developed to estimate the system states and lumped uncertainties of the rolling mill main drive system.To handle the motor torque saturation,an auxiliary signal system with the same order as the plant is constructed.The error between the control input and plant input is taken as the input of the constructed auxiliary system,and a number of signals are generated to compensate for the effect of the motor torque saturation.Furthermore,a robust output feedback controller is introduced to obtain better transient and steady-state performance of the rolling mill main drive system and the stability of the closed-loop system is strictly proved via Lyapunov theory.Finally,comparative simulations are performed to verify the effectiveness and superiority of the proposed control strategy.

Theoretical and Practical Studies of Determining the Force of the Lifting-Lowering of the Roll Box

The lifting and lowering mechanism of the roll box of the saw gin, being an integral part of the ginning process, is used when starting the electric motor of the saw cylinder until its rated speed is reached to prevent an increase in the load current on it, as well as to start the ginning process. The article defines the kinematics of the movement, and also studies the regularity of the movement of the roll box of the saw gin when lifting it with the help of a pneumatic drive. The kinematics of the roll box movement was determined through experimental studies. Knowing the equation of motion, using the second-order Lagrange equation, the regularity of the change in the lifting force of the roll box was determined. Here the system is closed, its degree of freedom is equal to one. The angle of rotation of the roll box is taken as a generalized coordinate. Numerical results were obtained using the Matlab software environment. The theoretical analysis and graphs for determining the lifting force of the roll box are presented. To study the kinematics of lifting the roll box, a method and a test bench have been developed. According to him, when the roll box was raised, its movement was recorded on video, the image was processed using the After Effect and CorelDraw programs, and the movement of the rod attachment point to the roll box was determined. And also the equation for changing the angle of rotation of the roll box is determined using the Matlab Curve Fiting program.

The main force driving forwards Chinese luxury market

It was during the weekend that Miss Wu lover a shop selling the luxury brand Louis VThrough the window, she could indulged in the filled with all kinds of handbags, dustcoats anheels-all she yearned for. But she tarried on thand found herself embarrassed to enter.

Nonlinear Dynamics of Torsional Vibration for Rolling Mill′s Main Drive System Under Parametric Excitation

The jointed shaft in the drivelines of the rolling mill, with its angle continuously varying in the production, has obvious impact on the stability of the main drive system. Considering the effect caused by the joint angle and friction force of roller gap, the nonlinear vibration model of the main drive system which contains parametric excitation stiffness and nonlinear friction damping was established. The amplitude-frequency characteristic equation and bifurcation response equation were obtained by using the method of multiple scales. Depending on the bifurcation response equation, the transition set and the topology structure of bifurcation curve of the system were obtained by using the singularity theory. The transition set can separate the system into seven areas, which has different bifurcation forms respectively. By taking the 1 780 rolling mill of Chengde Steel Co for example, the simulation and analysis were performed. The amplitude-frequency curves under different joint angles, damping coefficients, and nonlinear stiffness were given. The variations of these parameters have strong influences on the stability of electromechanical resonances and the characteristic of the response curves. The best angle of the jointed shaft is 4.761 3° in this rolling mill.

农业保险发展区域差异研究——基于主体动力分析的视角

鉴于我国农业保险存在着明显的区域间发展“不平衡不充分”问题,文章基于农业保险各主体(农民、保险公司、地方政府)动力的视角,从宏观层面出发,以省为区域,对影响各主体动力的多种因素和农业保险发展水平之间的关系进行了实证考察。结果发现,影响地区农业保险发展水平的主要因素有农民的收入结构、地方财政负担、历史赔付率、专业农业保险公司市场占有率、新型农业经营主体占比等。据此,针对农业保险发展水平相对落后的地区,从优化补贴结构、增加补贴种类、减轻县级财政负担、增设专业农业保险公司、差异化供给等角度提出政策建议。

基于主要驱动因子筛选法和深度学习算法的浙江省动态需水量预测

收集了浙江省2000—2020年各用水行业需水量数据,采用基于Spearman秩相关分析的主要驱动因子筛选法筛选了影响各行业需水量的主要驱动因子,进而构造了改进的长短时记忆(LSTM)神经网络需水量预测模型,对各行业需水量进行动态滚动预测,并将改进LSTM模型的预测结果与传统单变量LSTM预测模型、卷积神经网络模型、支持向量回归模型的预测结果进行了对比。结果表明,基于主要驱动因子筛选法改进的LSTM模型能实时动态滚动预测各行业每年需水量,且预测结果精度高于其他3种模型。

盾构机主驱动单唇形密封圈密封性能研究

以典型工况下盾构机主驱动单唇形密封圈为研究对象,利用单轴拉伸试验得到密封圈丁腈橡胶材料的应力-应变曲线,确定Yeoh三阶模型的材料参数;建立单唇形密封圈的二维轴对称有限元模型,研究介质压力、压差、摩擦因数和温度对其密封性能的影响规律。研究表明:介质压力主要影响最大接触应力,随着介质压力的增加,最大接触应力呈线性增加;介质压差主要影响最大接触应力和接触长度,随着介质压差的增加,最大接触应力先线性增加然后基本保持不变,而接触长度呈非线性增加;温度变化对密封性能的影响可以忽略;在考虑的工况条件下,单唇形密封圈唇口与旋转轴接触处产生的最大接触应力始终大于介质压力,密封性能良好。

小型凹槽环件复合环轧成形数值模拟

采用一种立式复合环轧工艺制造了小型凹糟环件,用Simufact有限元软件模拟了小型凹槽环件的环轧成形过程,并在D51环轧机上进行了验证。数值模拟结果揭示了环轧成形过程中几何、应变和温度等成形因素的分布和演化规律。为研究不同主动辊形状对环轧成形的影响,采用不同夹角的主动辊进行了数值模拟研究。结果表明,25.4°的主动辊夹角能产生更大的轧制力和内部塑性应变,但是容易产生椭圆缺陷和模具填充不满,因此选取适中的角度能保证工件的环轧质量。通过对比空转轧制前后的数值模拟结果发现,空转轧制可以显著改善椭圆缺陷,提高环件尺寸的均匀性。

永磁同步电机在细纱机上的节能应用

为降低棉纺企业的用电成本,对棉纺企业中用电需求量较大的环锭纺细纱机进行主传动系统节能改造,采用新型永磁同步电机替换原装三相异步电机,并将原主轴皮带传动改为联轴器直连驱动,同时对细纱机生产C 20 tex纱过程中的电机电流、温度以及细纱机能耗进行了测试与分析。测试结果表明:改进后细纱机主轴电机电流相较改进前降低了4 A~8 A;电机温度下降明显,其热损降低25%~40%;细纱机生产C 20 tex纱时每千克纱线耗电量下降约9%,有效达到了降低细纱机能耗的目的。

盾构机主驱动装配生产线关键技术研究与应用

针对盾构机主驱动装配效率低下和质量管控难度大的缺点,研制了一种集高效装配与数据传输于一体的主驱动装配生产线。在盾构机主驱动装配生产线总体设计方案的基础上,对主驱动零件自动化清洗、物料自动化转运、零/部件自动化装配、紧固件拧紧信息在线检测及存储和智能调度系统等关键技术展开研究,以高度集成的自动化设备取代传统人工装配流程,在提高主驱动装配质量和效率的同时实现了装配信息的管理与追溯,形成了主驱动装配生产线核心技术体系。最终设计的盾构机主驱动装配生产线顺利建成并完成了实际工艺验证,达到设计效果,现已成功应用于多种规格主驱动的装配生产作业,并取得了显著的经济效益。

拖拉机驱动系统对其性能和油耗的影响及试验研究

高机械性能和优化能源利用是机械化农业的重要发展目标。为此,通过优化拖拉机驱动系统,研究后轮驱动(RWD)、四轮驱动(4WD)和前轮驱动(FWD)对耕作作业中拖拉机性能和燃料使用的影响。选取轮胎充气压力分别为170、200、230kPa,压载质量分别为0、60、120kg,拉力分别为2、6和10kN,对高尔多尼拖拉机性能进行了测试。结果表明:4WD系统对拖拉机滚动阻力的影响最大,在不超过允许滑移的情况下可获得更高的牵引力;当拉力为2kN时,RWD系统的油耗最小,4WD系统的油耗最大;在10kN的拉力下,驱动系统的类型对降低油耗有显著影响,4WD系统的油耗达到了最低。

航天器用回转支撑机构设计优化及试验验证

本文结合国内空间站对日定向驱动机构所采用的回转支撑机构方案,重点围绕滚轮-导轨运动副接触形式,分析了圆柱形滚轮外形方案所存在的“滚中带滑”情况,针对性地开展了滚轮外形结构设计优化,提出了圆锥形设计改进方案。为了验证该方案的设计正确性、工程可行性以及改进有效性,计算了改进方案的运动副滚滑比,评估了零件加工精度、产品装配偏差以及空间温度环境等对滚滑比的影响,分析了改进方案对机械接口和载荷条件的影响,开展了真空寿命试验。结果表明:改进方案能够实现在理论上滚轮-导轨运动副为纯滚动运动,对零件加工精度、产品装配偏差以及空间温度环境有较好的容差性和适应性,并且对机械接口和载荷条件无影响,能够有效改善滚轮-导轨运动副接触状态,延长寿命,满足使用需求。

基于振动的驱动链松弛检测方法研究及张紧装置设计

针对自动扶梯运行过程中经常产生的异常噪音、梯路振动问题,对自动扶梯传动系统振动、振动频率、张紧问题进行了研究。首先,采用频谱分析方式分析了自动扶梯运行中出现的振动频率和谐波频率情况,与理论频率相对照,分析并寻找了异常振动频率的来源;然后,对可能的振动源做了进一步验证,并对确定的振动源进行了调整,根据振动测试结果判定了调整方法是否有效;最后,设计了一款便于观察和调整的主驱动链条张紧装置,其不仅改善了振动状态,而且可以在链条断裂状态下起到安全保护作用。研究结果表明:基于各振动源的固有频率和谐波频率,将实际频率与其相对照,可以快速确定振动源;对识别出的确定振动源有针对性地进行了调整,振动值最大降低了61.5%,提高了自动扶梯测试效率;使用张紧装置后,噪音降低达3.3 dB(A),有效改善了主驱动链条振动状态,提升了运行质量。