Mathematical model for the thermal process of controlled cooling of wires and its numerical simulation

The mathematical model for the thermal process of billets rolling has beenestablished, including transporting in air and temperature-holding cover, descaling withhigh-pressure water, and the process of rolling and cooling in water box. The calculated data by themodel have been compared with the measured data and the results show that the model is right andcreditable. Based on the model, the main thermal characters of rolling line have been simulated andthe influence of all the parameters on the temperature of rolling has been analyzed.

Nonlinear adaptive optimal control for vehicle handling improvement through steer-by-wire system

A control algorithm for improving vehicle handling was proposed by applying right angle to the steering wheel,based on the nonlinear adaptive optimal control(NAOC).A nonlinear 4-DOF model was initially developed,then it was simplified to a 2-DOF model with reasonable assumptions to design observer and optimal controllers.Then a simplified model was developed for steering system.The numerical simulations were carried out using vehicle parameters for standard maneuvers in dry and wet road conditions.Moreover,the hardware in the loop method was implemented to prove the controller ability in realistic conditions.Simulation results obviously show the effectiveness of NAOC on vehicle handling and reveal that the proposed controller can significantly improve vehicle handling during severe maneuvers.

Program structures and synchronization schemes in numerical coordinate controllers of three-wire welding

In the three-wire welding system, a welding process consists of the operations of four devices, namely three welding machines and one bogie. The operations need to be synchronized by a numerical coordinate controller （ NCC ）. In this paper, we will discuss a tnsk-job-procedure cubic program structure. Under this structure, the devices are synchronized and isolated at the same time. This cubic program structure can also be used as a reference for other multi-device or multi-unit manufacturing processes.

Application of Feedforward and Feedback Control Strategy for Wire Rod Hot Rolling Line

The feedforward and feedback control strategy of water flowrate based on the analysis of thermal process in water cooling box was proposed, and the control strategy was applied to wire rod hot rolling at Baosteel Co. The operation has proved that the strategy can control water flowrate in the cooling water box reasonably to ensure the temperature requirement of the wire discharged from the cooling water box.

Self-learning fuzzy neural network control for backside width of weld pool in pulsed GTAW with wire filler

The weld pool shape control by intelligent strategy was studied. In order to improve the ability of self-learning and self-adaptation of the ordinary fuzzy control, a self-learning fuzzy neural network controller (FNNC) for backside width of weld pool in pulsed gas tungsten arc welding (GTAW) with wire filler was designed. In FNNC, the fuzzy system was expressed by an equivalence neural network, the membership functions and inference rulers were decided through the learning of the neural network. Then, the FNNC control arithmetic was analyzed, simulating experiment was done, and the validating experiments on varied heat sink workpiece and varied gap workpiece were implemented. The maximum error between the real value and the given one was 0.39mm, the mean error was 0.014mm, and the root-mean-square was 0.14mm. The real backside width was maintained around the given value. The results show that the self-learning fuzzy neural network control strategy can achieve a perfect control effect under different set values and conditions, and is suitable for the welding process with the varied structure and coefficients of control model.

Rectifying control of wire diameter during dieless drawing by a deformation measuring method of interframe displacement

A deformation measurement method of interframe displacement was proposed in this paper. By online monitoring the shape di- mensions of both the deformation zone and its adjacent zone by machine vision, the initial and terminative positions of deformation were dynamically identified during dieless drawing, and the global monitoring and online closed-loop control of the deformation zone were achieved. The dieless drawing process was systematically carried out on NiTi shape memory alloy wires. It is shown that the deformation measurement method of interframe displacement can track the axial displacement of the wires, but this cannot be achieved by traditional machine vision. The initial and terminative positions of deformation can be accurately identified by this method. The proposed rectifying control technology can effectively decrease the wire diameter fluctuation during dieless drawing, that is, the standard deviation of the wire diameter fluctuation could be decreased fi＇om 0.30 to 0.08 mm after three passes of dieless drawing, indicating that the control system has a good rectifying ability.

Neuron self-learning PSD control for backside width of weld pool in pulsed GTAW with wire filler

In this paper, the weld pool shape control by intelligent strategy was studied. A neuron self-learning PSD controller for backside width of weld pool in pulsed GTAW with wire filler was designed. The PSD control arithmetic was analyzed, simulating experiment by MATLAB software was done, and the validating experiments on varied heat sink workpiece and varied gap workpiece were successfully implemented. The study results show that the neuron self-learning PSD control method can attain a perfect control effect under different set values and conditions, and is suitable for the welding process with the varied structure and coefficients of control model.

A Study on a Wire Tension Adaptive Control System of a Multi-wire Saw in Computer Simulation

Based on the analysis of the mechanism of wire tension control by using torque motors in the multi-wire saw machining process, some mathematical models of a tension control system are studied, and an adaptive algo- rithm is designed for controlling the wire tension. In this algorithm of tension control, the rotation speeds and waving angle of motors are measured and fed back to the controller, and the NLMS（ normalized least mean squares） algorithm is used to calculate the adaptive correction value and control the wire tension accurately. The computer simulation results in Matlab software validate the high accuracy for controlling the system of the wire tension with the NLMS algorithm in the multi-wire saw machining process.

RULED SURFACE MACHINING BY 4-AXES SIMULTANEOUS CONTROL WIRE-EDM

On the tasis of study in the mathematical model of 3-dimensional ruled surface (RS),this paper introduces a new concept of distance paramcter (DP) and also puts forward that themethod of modeling a RS depends on not only two boundary curves but also DP. According toabove theory, the formulas to calculate corresponding point coordinates to any kind of top and bot-tom profile of a workpiece and formulas to calcuate the maximum inclination angle of ruling linehave been obtained. Then a different top and bottom RS mathining method including profile withline-are combination as well as parametric curves has been achieved by 4-axes simultancous con-trol programming proposed.

NEW METHOD FOR VIBRATION MEASUREMENT AND CONTROL OF MOVING WIRE

On-line measurement and control method of moving wire vibration are developed. The response measurement of the wire is indirectly accomplished by 'vibration transfer method ' and active con- trol is carried out on the vibration receiving body by piezoelectric ceramics. The fundamental princi- ples of measurement and control are stated and experimental results are presented.

线控主动四轮转向汽车控制策略研究

目的针对线控四轮转向汽车横向稳定性不足及控制鲁棒性差等问题,提出一种主动转向反馈控制策略。方法使用Simulink搭建线控转向系统转向执行机构动力学模型,将MATLAB/Simulink与Carsim联合仿真,建立线控四轮转向整车模型;基于二自由度模型分析横摆角速度和质心侧偏角对汽车稳定性的影响,推导理想的横摆角速度和质心侧偏角;以横摆角速度增益恒定为依据设计理想传动比,得到期望前轮转角,以横摆角速度误差为控制量设计模糊控制器得到附加前轮转角对期望转角实时修正,实现前轮主动转向;针对横摆角速度和质心侧偏角与理想值之间的误差,加权得到稳定性控制目标;设计自适应积分滑模反馈控制策略输出后轮转角,对理想值进行跟踪,实现后轮主动转向。结果仿真实验结果表明:所搭建的线控转向系统能够准确反映汽车动力学特性。相比无控制的机械前轮转向汽车与横摆反馈控制的四轮转向汽车,线控主动四轮转向汽车在双移线工况下将质心侧偏角控制在0值附近波动,横摆角速度跟踪误差控制在1.149 deg/s以内;在角阶跃工况下将质心侧偏角稳态值控制在0.065 deg,横摆角速度稳态值误差为0.074 deg/s。结论线控主动四轮转向控制策略在双移线和角阶跃工况下控制效果显著,鲁棒性能好,能有效提高汽车的操纵稳定性和主动安全性。

面向线控制动车辆单轮制动失效的稳定性控制

基于线控制动系统四轮可独立控制的特点,提出一种协同线控转向与线控制动的制动力实时分配的控制方法。该方法根据三轮富余制动力能否补偿失效轮损失制动力,按制动强度分为轻度、中度和重度制动3种工况,针对重度制动工况下制动力补偿不足问题,基于积分滑模控制方法设计前轮主动转向器,综合考虑单轮制动失效时各轮垂直载荷的变化和前轮转角介入后轮胎力的耦合,采用序列二次规划算法(sequental quadratic programming,SQP),实时分配剩余三轮制动力。仿真结果表明:在不同制动强度及不同轮制动失效下所提控制方法相较于无控制,横向跑偏分别减少了89.98%、91.90%、96.96%、89.62%,制动强度至少达到正常制动时的97.5%。因此,该控制方法在保证横向稳定性的同时最大限度地满足驾驶员的制动期望,有效抑制因单轮制动失效导致的车辆跑偏甩尾等问题。

基于双闭环控制的三相四线制逆变器控制研究

三相四线制逆变器具有更好的不平衡负载驱动能力,被广泛用于不间断电源等领域。对于这种离网模式下的逆变器而言,通常使用电压电流双闭环控制模式对输出进行控制。提出一种无需坐标变换的电压电流双闭环控制,实现输出三相之间完全解耦。由于准比例谐振(Quasi Proportional Resonance,QPR)控制对交流信号的控制效果更好,因此电压外环采用QPR控制,电流内环采用比例控制。实验证明了所提控制方法的有效性。

电弧熔丝增材制造控形技术研究现状与展望

金属增材制造是制造强国战略下推动我国高端装备制造业转型升级的重点发展方向。电弧增材制造以其高沉积效率、低成本、可进行复杂结构直接成形等优势受到了广泛的关注。但增材过程中涉及的物理过程复杂,成形质量与精度面临很大挑战。针对电弧增材制造技术短流程、长周期的制造特征,讨论如何从热源上降低成形偏差、从过程上降低制造误差、从结果上改善成形精度,介绍了一系列创新的热源调制、过程控制与结果优化的方法策略,总结了现有技术存在的问题与面临的挑战,为如何进一步提升电弧增材过程的成形控制效果提出了几点思考。

面向全矢量线控车辆极限运动的分层式协同控制

装配四轮分布式驱动-转向(4WID-4WIS)底盘的全矢量线控车辆具备多可控自由度、高速稳定性强的特点,是极限工况稳定裕度和安全性较高的理想车型。为了解决全矢量线控车辆在极限工况下纵横向控制冲突危害行车安全的问题,提出一种基于模型预测控制(MPC)的分层式车辆纵向和横向运动协同控制方法。建立基于单轨模型的期望运动状态识别方法,设计模型预测控制器转换动力学目标,采用泰勒展开和前向欧拉方法对预测模型进行线性离散化处理;设计基于负荷率的轮胎力优化分配方法,利用反正切轮胎逆模型求解控制执行量。仿真结果表明,协同控制方法能显著提高车辆在不同路面下的极限运动稳定性,更精准地跟踪期望运动状态,扩大稳定裕度,保障行车安全。

1-wire技术在温室集成控制系统中的应用

简述了基于1-wire技术的控制网络。根据温室环境的特殊要求,分析了控制集成技术的特点,并讨论了温室控制系统中采用1-wire控制网络的性能及相关集成技术。根据温室的控制要求,利用1-wire技术构建了温室控制系统。

基于1-Wire技术的数字温度仪

设计了一种基于单总线技术的温度测量仪器。介绍了单总线原理、DS18B20的工作时序和该温度测量仪器的测温原理。给出了硬件设计框图,并在软件编写部分给出了延时函数的设计。实验结果表明,该测温仪器具有操作简单直观、精度高、工作稳定可靠等特点。

一总线在北京谱仪实验模型BESⅢ Slow Control中的应用

介绍了北京正负电子对撞机国家重点工程中,BESⅢS low Con tro l在全新北京谱仪中的重要性,并对通过在三个探测器:M uon RPC、量能器EM C、漂移室M DC实验模型中的具体实例应用,介绍了慢控制主要采用的一总线技术。

经皮克氏针固定在急性不稳定型踝关节骨折“损害控制”中的应用

目的探讨经皮克氏针胫距跟临时固定在急性闭合性不稳定踝关节骨折“损害控制”应用中的安全性与有效性。方法回顾性分析2018年6月—2022年3月江门市中心医院运动医学与足踝外科采用经皮克氏针胫距跟临时固定技术进行“损害控制”的23例急性闭合性不稳定踝关节骨折患者,男性13例,女性10例;年龄18~78岁,平均44.6岁。跌倒扭伤7例,运动伤5例,道路交通伤7例,高处坠落伤4例。Tscherne分型Ⅰ级8例,Ⅱ级8例,Ⅲ级7例。C型臂X线机下手法复位,于足底经皮从远端向近端跨胫距跟关节纵向置入1枚2.5 mm及1枚2.0 mm克氏针。记录患者从Ⅰ期克氏针固定手术至Ⅱ期内固定手术的天数及出现相关并发症的情况,术后12个月随访记录足踝结局评分(FAOS)。结果本组患者均未发生皮肤坏死、针道感染、切口愈合不良等并发症,Ⅱ期内固定等候天数为(9.5±2.5)d,术后12个月FAOS为(85.8±4.6)分。结论经皮克氏针胫距跟固定应用于急性闭合性不稳定踝关节骨折是一种经济、有效、安全并适宜推广的“损害控制”手段。

超高海拔地区1000kV变电站导线连接金具防晕型结构设计与优化

防晕型金具设计是特高压变电站电晕防治和电磁环境治理的关键,特别是在高海拔地区,电晕防治尤为重要。采用有限元仿真和试验相结合的研究方法,提出了满足工程需求的海拔校正指数公式、线性公式和金具表面场强控制值,计算获得了高海拔特高压变电站导线连接金具表面的电场分布,给出了各导线连接金具的结构优化方案并通过了高海拔电晕试验验证。结果表明:按文中推荐方法计算得到的4000m海拔校正系数为1.51,与标准Q/GDW 551—2010推荐值相差1.9%。高海拔特高压变电站中导线连接金具表面场强应进行差异化控制:上层金具不超过1.32kV/mm,局部不超过1.52kV/mm;下层金具不超过0.99kV/mm,局部不超过1.14kV/mm。采用所提推荐方案时,各导线连接金具电晕熄灭电压均高于698.5kV且保有一定安全裕度,可满足4000m高海拔特高压变电站使用要求。研究成果可为我国超高海拔地区特高压变电站的防晕型金具设计提供依据,助力我国构建绿色环保的新型能源体系。