一种滚动型抗金属超高频RFID标签天线的设计

提出一种滚动型抗金属超高频RFID标签天线。标签天线为正八边形柱状结构,四个天线辐射臂设计在正八边形的拐角处,其中一组相邻两臂通过馈电面与同轴线内导体相连,另一组相邻两臂通过接地面与同轴线外导体相连,标签天线芯片连接于同轴线的另一端。标签天线体积为76 mm×13 mm×13 mm。在金属面上滚动至各种放置状态时,天线中心频率变化范围为900~923 MHz,|S11|≤-10 dB的带宽为9~14 MHz,天线辐射效率均超过80%。该标签天线具有可以在金属背景环境中任意面滚动以及小型化、高效率等优势,适用于复杂工业物联网环境的RFID系统中。

金属表面任意滚动型RFID探测标签天线的研究

射频识别(RFID)技术在工业探测领域的应用不断深入,对RFID标签在多金属环境中的读取性能提出了更高的要求,本文提出一种可以在金属表面任意滚动的高效率RFID标签天线。所设计的滚动型标签天线是由倒F天线(IFA)进化而成,天线采用了呈柱状布局的4个辐射臂,其中一组相对的两臂通过馈电面与同轴线芯线相连,另一组相对两臂与同轴线外导体相连,一开槽的矩形辅助面置于四个辐射臂中心。标签天线体积为11.3 mm×11.3 mm×77.5 mm,在金属平面上各种状态滚动时中心频率变化范围为897~932 MHz,|S_(11)|≤-10 dB的带宽范围为3.5~8 MHz,天线辐射效率达到70%。该无源标签天线具有可以在金属背景环境中任意滚动、小型化、高效率等优势,无源标签天线与温度传感器芯片相连,可用于工业物联网复杂环境温度探测。

“滚动型开放式”实践技能培养模式的探讨与实践

如何真正焊补课堂理论教学、实验室技能训练和基地生产技能实践三者之间的裂缝一直是高职技能型人才培养的重要研究课题。本文针对高职院校涉农专业实践性强、农业生产季节性强的特点。分析了传统的计划性实践教学模式中存在亟待解决的几个问题．并进一步提出高职院校实施“滚动型开放式”实践技能培养模式的意义和方式，为探索涉农专业学生的技能培养模式提供参考。

滚动型单面碰撞调谐质量阻尼器参数优化及减振性能分析

滚动型单面碰撞调谐质量阻尼器是一种由小球、圆形轨道、黏弹性材料挡板组成的减振装置,通过小球与挡板的碰撞耗能以及小球与圆形轨道间的摩擦进行减振。基于Lagrange变分原理,建立单自由度结构与滚动型单面碰撞调谐质量阻尼器的运动方程,研究不同质量比下滚动型单面碰撞调谐质量阻尼器的参数优化,分析自由振动、简谐激励以及地震作用下滚动型单面碰撞调谐质量阻尼器的减振性能。结果显示,滚动型单面碰撞调谐质量阻尼器具有良好的减振效果。

滚动型平面钢闸门三维有限元分析

滚动型钢闸门是一种常见的钢闸门形式,其结构安全性直接关系到水工建筑物能否正常发挥功能。本文基于ANSYS对滚动型平面钢闸门进行三维有限元分析,对钢闸门主要构件进行强度和刚度校核,并对钢闸门滚轮结构进行精细模拟。结果表明,钢闸门主要构件满足材料强度、刚度要求,但在滚轮轴与门叶连接部位存在应力集中现象,在设计和制造过程中应予以重视。

非小量角位移假定下滚动型调谐质量阻尼器的减振分析

对滚动式调谐质量阻尼器(TRMD)中球形振子转角位移的小量假定问题进行了深入研究,运用Lagrange运动方程推导了TRMD在球形振子小量假定和非小量假定下的受控体系动力方程,给出了数值解法。结合算例探讨了在简谐激励和地震作用下设置有TRMD的受控体系减振情况,比较和分析了小量假定与非小量假定对受控结构控制性能的影响。结果表明,当外激励较强时小量假定对控制结构的减振分析影响较大,会放大其减振效果,其适用性与激励种类及强度有关,具有一定的局限性,不容忽视。论文同时对小量假定的适用范围进行了探讨。

基于Romax柔性模型的风电主轴圆锥滚子轴承接触应力和疲劳寿命分析

风电机组轴承是高性能风机的核心部件,为了开发更高性能的风电机组轴承,需要对轴承的性能与寿命做出合理评价。基于轴承经典理论和软件仿真分析的结果,提出一种评价轴承性能指标的新方法。利用Romax软件搭建风机传动链柔性模型,以实际服役的风机机型为载体,在充分考虑风机所受复合载荷的前提下,分析滚动体修型量对于风机主轴轴承服役性能的影响。结果表明:所提方法能够考虑到轴系各部件的变形对于轴承滚动体载荷的影响,同时计算出较为合理的轴承风载合成寿命。对于滚动体不同修型量的比较,过小的修型量会导致应力集中,过大的修型量会造成接触区域变短,合适的修型量需要根据轴承受力情况具体分析。

基于滚动时域的线性二次型路径跟踪研究

针对智能驾驶车辆在实际行驶过程中的路径跟踪问题,建立了二自由度车辆动力学模型和路径跟踪预瞄模型,并将两者相结合。将给定的双移线和蛇形线路径作为滚动时域线性二次控制器模型的输入,将得到的转向盘转角输入车辆模型,得到了车辆横向速度、横摆角速度、横向位移和横摆角。仿真结果表明,提出的路径跟踪控制策略能够使车辆在换道时始终维持方位偏差在0.06 m以内,同时具有较好的横向稳定性。

冲模滚动导柱模架尺寸链设计

就常用的滚动导柱型（滚动体保持在导柱上）模架提出九个公式来限定模架的最大和最小闭合高度，并对一种规格的国际模架进行了校核以判别设计的合理性。

PTRMD在多自由度结构中的减振性能及鲁棒性

将一种带碰撞的滚动型调谐质量阻尼器(PTRMD)应用于多自由度结构中,对其在多自由度结构体系中的减振性能及阻尼器频率失谐时的鲁棒性进行研究。通过拉格朗日方程推导得到分段运动方程,然后推广到多自由度结构中,建立了设有该装置的多自由度受控系统的动力方程,并利用数值方法求解。把PTRMD安装到6层结构中,对其在自由振动和强迫振动时的控制效果进行探讨,并与无碰撞的滚动型调谐质量阻尼器(TRMD)进行了比较,同时对它们在阻尼器频率偏离最优频率时的鲁棒性进行了分析。结果表明:在多自由度结构中安装PTRMD能有效减小结构的动力反应,得到满意的减振效果;相比TRMD,PTRMD具有减振性能好、控制频带宽、适用性强、受阻尼器频率变化的影响不大等优点,具有更广大的应用前景。

电信运营企业投资效益评价体系探索

本文从分析电信运营企业在投资特点及投资效益存在的问题入手,阐述了投资效益评价的两种主要方法——边际分析法和现金流量分析法的基本内容,列举实例就采用这两种方法分别对宽带接入等滚动型投资业务及ICT等项目型投资业务进行投资效益评价,得出结论:对滚动型投资业务应加大现网存量的资源挖掘及市场营销;对ICT等项目型投资业务应优先选择集成模式、加强现金流等管理并利用现有网络资源,以此为提高电信运营企业投资效益提供建议和指导。

控制输入受限的板球系统滚动线性二次型调节器控制

为了实现板球系统高精度的轨迹跟踪目标,首先根据目标轨迹,利用微分平坦技术得到前馈控制量和目标状态量。然后,基于目标状态建立偏差系统,结合预测控制中的滚动优化思想设计了滚动线性二次型(LQR)控制器。最后,考虑到被控对象输入受限的情况,在变椭圆域约束的条件下优化控制系统性能,并通过本地管理接口(LMI)求解出控制器。仿真结果显示,在输入受限的情况下,板球系统具有良好的轨迹跟踪性能、稳态性能和鲁棒性能。

Design of an optimal active stabilizer mechanism for enhancing vehicle rolling resistance

Improving rollover and stability of the vehicles is the indispensable part of automotive research to prevent vehicle rollover and crashes.The main objective of this work is to develop active control mechanism based on fuzzy logic controller(FLC) and linear quadratic regulator(LQR) for improving vehicle path following,roll and handling performances simultaneously.3-DOF vehicle model including yaw rate,lateral velocity(lateral dynamic) and roll angle(roll dynamic) were developed.The controller produces optimal moment to increase stability and roll margin of vehicle by receiving the steering angle as an input and vehicle variables as a feedback signal.The effectiveness of proposed controller and vehicle model were evaluated during fishhook and single lane-change maneuvers.Simulation results demonstrate that in both cases(FLC and LQR controllers) by reducing roll angle,lateral acceleration and side slip angles remain under 0.6g and 4° during maneuver,which ensures vehicle stability and handling properties.Finally,the sensitivity and robustness analysis of developed controller for varying longitudinal speeds were investigated.

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 technol- ogy 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 48 axis 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 preci- sion 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 svner^ic movement

Simulation-based multi-objective optimization for roll shifting strategy in hot strip mill

A simulation-based multi-objective optimization approach for roll shifting strategy in hot strip mills was presented. Firstly, the effect of roll shifting strategy on wear contour was investigated by mtmerical simulation, and two evaluation indexes including edge smoothness and body smoothness of wear contours were introduced. Secondly, the edge smoothness average and body smoothness average of all the strips in a rolling campaign were selected as objective functions, and shifting control parameters as decision variables, the multi-objective method of MODE/D as the optimizer, and then a simulation-based multi-objective optimization model for roll shifting strategy was built. The experimental result shows that MODE/D can obtain a good Pareto-optimal front, which suggests a series of alternative solutions to roll shifting strategy. Moreover, the conflicting relationship between two objectives can also be found, which indicates another advantage of multi-objective optimization. Finally, industrial test confirms the feasibility of the multi-objective approach for roll shifting strategy, and it can improve strip profile and extend same width rolling miles of a rolling campaign from 35 km to 70 km.

Auto Identification of Rolling Layers in Roller-Compacted Concrete Dam

A scheme for identifying rolling layers in roller-compacted concrete (RCC) dam automatically was presented. First, a conceptual model was developed. Second, by using a computational geometry method, the auto identification of rolling layers and auto matching between rolling compaction machines and rolling layers were realized based on spatial control points. An application to the construction of Guandi RCC dam showed that the auto identification of rolling layers played an important role in ensuring the engineering quality.

铝箔搪瓷的耐磨性能测定方法

本文就铝箔搪瓷的耐磨性能测定方法进行了探索,采用GM-2型滚动磨耗仪,选择负载、橡胶砂轮规格、磨转次数对样品加以研磨即可达到测试要求。实验结果证明,本方法适用于铝箔搪瓷产品的耐磨性能测定。

挖掘机中间架通用搭焊模具设计与制造

本文介绍了挖掘机焊接结构件产品中间架通用搭焊模设计及其制作、组装的关键技术。为工程机械行业实际生产中焊接结构件的工装设计与制造提供了技术参考。

Numerical simulation of wheel wear evolution for heavy haul railway

The prediction of the wheel wear is a fundamental problem in heavy haul railway. A numerical methodology is introduced to simulate the wheel wear evolution of heavy haul freight car. The methodology includes the spatial coupling dynamics of vehicle and track, the three-dimensional rolling contact analysis of wheel-rail, the Specht's material wear model, and the strategy for reproducing the actual operation conditions of railway. The freight vehicle is treated as a full 3D rigid multi-body model. Every component is built detailedly and various contact interactions between parts are accurately simulated, taking into account the real clearances. The wheel-rail rolling contact calculation is carried out based on Hertz's theory and Kalker's FASTSIM algorithm. The track model is built based on field measurements. The material loss due to wear is evaluated according to the Specht's model in which the wear coefficient varies with the wear intensity. In order to exactly reproduce the actual operating conditions of railway,dynamic simulations are performed separately for all possible track conditions and running velocities in each iterative step.Dimensionless weight coefficients are introduced that determine the ratios of different cases and are obtained through site survey. For the wheel profile updating, an adaptive step strategy based on the wear depth is introduced, which can effectively improve the reliability and stability of numerical calculation. At last, the wear evolution laws are studied by the numerical model for different wheels of heavy haul freight vehicle running in curves. The results show that the wear of the front wheelset is more serious than that of the rear wheelset for one bogie, and the difference is more obvious for the outer wheels. The wear of the outer wheels is severer than that of the inner wheels. The wear of outer wheels mainly distributes near the flange and the root; while the wear of inner wheels mainly distributes around the nominal rolling circle. For the outer wheel of front wheelset of each bogie, the development of wear is gradually concentrated on the flange and the developing speed increases continually with the increase of traveled distance.