An optimization algorithm for locomotive secondary spring load adjustment based on artificial immune

In order to control the locomotive wheel(axle) load distribution, a shimming process to adjust the locomotive secondary spring loads was heretofore developed. An immune dominance clonal selection multi-objective algorithm based on the artificial immune system was presented to further improve the performance of the optimization algorithm for locomotive secondary spring load adjustment, especially to solve the lack of control on the output shim quantity. The algorithm was designed into a two-level optimization structure according to the preferences of the problem, and the priori knowledge of the problem was used as the immune dominance. Experiments on various types of locomotives show that owing to the novel algorithm, the shim quantity is cut down by 30% 60% and the calculation time is about 90% less while the secondary spring load distribution is controlled on the same level as before. The application of this optimization algorithm can significantly improve the availability and efficiency of the secondary spring adjustment process.

Method for secondary spring load equalization of railway vehicles with two-stage spring suspension: Modeling and optimal regulation

To ensure running safety,the secondary spring loads of railway vehicles must be well equalized.Due to the coupling interactive effects of these hyper static suspended structures,the equalization adjustment through shimming procedure is quite complex.Therefore,an effective and reliable method in application is developed in this paper.Firstly,the best regulation of spring load is solved based on a mechanical model of the secondary suspension system,providing a target for actual adjustment.To reveal the relationship between secondary spring load distribution and shim quantity sequence,a forecasting model is constructed and then modified experimentally with consideration of car body’s elastic deformation.Further,a gradient-based algorithm with a momentum operation is proposed for the load optimization.Effectiveness of the whole method has been verified on a test rig.It is experimentally confirmed that this research provides an important basis for achieving an optimal regulation of spring load distribution for multiple types of railway vehicles.

Modeling of Cross-Spring Pivots Subjected to Generalized Planar Loads

Cross-spring pivots, formed by crossing two identical flexural beams at their midpoint, have been broadly used in precision engineering and aerospace fields. Many researches have been conducted on modeling and analysis of cross-spring pivots. However the influence of application position and magnitude of the external loads on the load-rotation and parasitic motion characteristics has not yet been discussed. In order to reveal the effect of the external loads, this paper develops the accurate load-rotation and center shift models of cross-spring pivots, with generalized planar loads applied including bending moment, horizontal and vertical forces. Firstly, by using the energy method, the load-displacement models of the pivot are derived with the assumption of small rotational angles. Based on the models, the influence of generalized planar loads on the load-rotation relationship is discussed, which shows that both application position and magnitude of the vertical and horizontal forces influence the load-rotation behaviors. Then the accurate center shift expressions of the pivot with generalized planar loads are developed, which shows that the rotational angle is the dominant term for both components of the center shift while the vertical and horizontal forces are small. Finally, the accuracy of the proposed model is validated by finite element analysis（FEA）. Comparing the model data with the results obtained from FEA, the relative error of the load-rotation is less than 6% even if the rotational angle reaches 20°; the relative errors of the two components of center shift are less than 5% and 10% respectively when the rotational angle reaches 10°. The proposed model and analytical conclusions can be used to analyze and preliminarily design the compliant mechanisms containing cross-spring pivots.

Analysis on the Performance of the SLIP Runner with Nonlinear Spring Leg

The spring-loaded inverted pendulum(SLIP) has been widely studied in both animals and robots.Generally,the majority of the relevant theoretical studies deal with elastic leg,the linear leg length-force relationship of which is obviously conflict with the biological observations.A planar spring-mass model with a nonlinear spring leg is presented to explore the intrinsic mechanism of legged locomotion with elastic component.The leg model is formulated via decoupling the stiffness coefficient and exponent of the leg compression in order that the unified stiffness can be scaled as convex,concave as well as linear profile.The apex return map of the SLIP runner is established to investigate dynamical behavior of the fixed point.The basin of attraction and Floquet Multiplier are introduced to evaluate the self-stability and initial state sensitivity of the SLIP model with different stiffness profiles.The numerical results show that larger stiffness exponent can increase top speed of stable running and also can enlarge the size of attraction domain of the fixed point.In addition,the parameter variation is conducted to detect the effect of parameter dependency,and demonstrates that on the fixed energy level and stiffness profile,the faster running speed with larger convergence rate of the stable fixed point under small local perturbation can be achieved via decreasing the angle of attack and increasing the stiffness coefficient.The perturbation recovery test is implemented to judge the ability of the model resisting large external disturbance.The result shows that the convex stiffness performs best in enhancing the robustness of SLIP runner negotiating irregular terrain.This research sheds light on the running performance of the SLIP runner with nonlinear leg spring from a theoretical perspective,and also guides the design and control of the bio-inspired legged robot.

Estimation of Springing Response for 550 000 DWT Ore Carrier

The desire to benefit from economy of scale is one of the major driving forces behind the continuous growth in ship sizes. However, models of new large ships need to be thoroughly investigated to determine the carrier's response in waves. In this work, experimental and numerical assessments of the motion and load response of a 550,000 DWT ore carrier are performed using prototype ships with softer stiffness, and towing tank tests are conducted using a segmented model with two schemes of softer stiffness. Numerical analyses are performed employing both rigid body and linear hydroelasticity theories using an in-house program and a comparison is then made between experimental and numerical results to establish the influence of stiffness on the ore carrier's springing response. Results show that softer stiffness models can be used when studying the springing response of ships in waves.

Modeling and Simulation of Diaphragm Spring Clutch

A model was developed to simulate a vehicle diaphragm spring clutch with the evaluation indicators of jerk degree and friction work.First,the pressing load characteristic of the driven plate of the diaphragm spring clutch was analyzed.Then,the clutch dynamic characteristic under each state was studied according to the basic principles of tribology.Finally,the mathematical model of the clutch was developed.Based on the model,the performance of a vehicle was simulated.The simulation results show that the model can predict the dynamic characteristic of the clutch correctly and evaluate the performance of the clutch engagement effectively.The model can be used for theoretical research of automatic clutch control and can be easily applied to simulate vehicle longitudinal dynamics.

基于位错运动的弹簧应力松弛方程应用研究

评价弹簧的强压处理工艺、预测弹簧的贮存寿命和载荷损失具有重要的工程意义。本文对圆柱螺旋压缩弹簧进行应力松弛试验,利用基于位错运动的应力松弛方程对加速试验数据进行拟合分析,提出评价弹簧强压处理效果的方法,并对应力松弛方程进行线性化处理,导出弹簧寿命预测方程和载荷预测方程,给出计算载荷损失误差的方法,预测圆柱螺旋压缩弹簧的寿命和载荷损失,并对其进行试验验证。结果表明:本文提出的弹簧应力松弛方程效果较好,载荷损失预测误差在±2%以内。

基于非线性弹簧的圆锥滚子轴承建模与分析

为解决风机主轴承滚动体数目多、尺寸大,进行有限元分析计算量大、收敛困难的难题,提出一种基于非线性弹簧的圆锥滚子轴承有限元等效模型,滚动体沿轴线方向分片,各分片与滚道接触以及球基面与挡边接触的“载荷-变形”关系采用弹簧单元等效模拟,等效弹簧的刚度通过赫兹接触理论确定。以某兆瓦级风机主轴承为例分析了该模型滚动体载荷分布及套圈整体变形,并与实体滚动体接触分析计算结果进行了对比。结果表明:基于非线性弹簧的等效模型能准确反映轴承内部载荷分布及整体变形情况,大大缩减计算量,为风机圆锥滚子主轴承的设计与分析提供了理论依据和指导。

带有指令滤波的电力弹簧系统反步控制

针对新能源发电系统因间接性和不确定性导致的电压波动问题,文中首次将反步控制策略应用于电力弹簧(electric spring,ES)系统,并提出一种带有指令滤波的ES反步控制策略。根据ES的数学模型利用反步法设计控制器,并加入指令滤波器,以解决ES反步控制中的计算膨胀问题,同时设计误差补偿信号,并利用Lyapunov稳定性理论验证系统稳定性。通过仿真模拟新能源发电系统网侧电压波动时,ES对关键负载(critical load,CL)电压稳定的效果,以及不同系统参数对文中控制策略的敏感性分析。与传统的比例积分(proportional-integral,PI)控制对比,CL电压动态响应速度提高0.07 s,CL电压畸变率降低31%,参数敏感性分析中CL电压最大偏差率为0.318%,能承受的最大电压幅值波动范围提高52.9 V。仿真结果验证了文中所提出的控制策略具有响应速度快、谐波含量低、抗干扰能力强的优势。

高速线切割机床上丝辅助装置设计

现有高速线切割机床的上丝装置在上丝过程中易发生断丝与张紧力不均衡现象,降低了机床切削稳定性和工件加工质量。通过分析现有装置的结构,提出增加推力球轴承,以防止锁紧螺母跟转而导致储丝盘卡顿引起断丝;根据丝线的拉力计算出弹簧压缩量及其他相关参数。经I-DEAS软件建模、装配、仿真表明,该装置可以满足生产要求。

1000MW汽轮机中压阀门异常振动分析及治理

针对某型超超临界1000MW机组运行过程中出现中压阀门振动过大的异常现象,对中压阀门以及机组轴系振动进行测试及分析,得出中压阀门振动以50Hz分量为主,与机组转频、阀门固有频率比较接近,表明中压阀门存在结构共振现象,且激振源为中压转子。进一步分析表明:中压缸进汽阀门组弹簧支撑刚性不足、中压缸载荷不均,是诱发中压阀门结构共振的主要原因。在检修中,更换新的中压阀门支撑弹簧,并提高其预压紧量,提升其刚度及稳定性;对中压缸缸体进行载荷分配,提升缸体稳定性,从而降低中压转子振动对阀门的影响。处理后,1000MW机组中压阀门振动大幅降低,提高了机组的安全可靠性,具有很好的工程借鉴价值。

振动台控制室抗倾斜空气弹簧三维隔振平台研究

大型地震模拟振动台的运行给周围环境带来不可忽略的振动问题,影响精密仪器设备的正常使用及工作人员的舒适度。针对国家大型地震工程模拟研究设施振动台控制室面临的振动问题,提出一种基于带附加气室的空气弹簧和抗倾斜装置的大质量三维隔振平台。开展了隔振部件以及隔振平台的试验研究以及数值模拟分析,提出了抗倾斜装置的抗倾斜刚度理论计算公式。研究结果表明,带附加气室的锥型与直筒型膜式空气弹簧可实现约1 s竖向隔振周期,阻尼比达23%。试验中抗倾斜装置可有效控制人员偏心荷载造成的平台倾斜问题,平台倾斜角度减小达66%。所设计国家大型地震工程模拟研究设施隔振平台可大幅降低振动台运行产生振动影响,隔振效率达86%以上。

基于P波斜入射海相软土区螺旋桩动力响应分析

在地震频发地区,越来越多建筑使用螺旋桩作为基础,此桩型具有良好的抗震能力。通过建立三维有限元模型,基于黏弹性人工边界,把地震作用等效为边界结点上的作用力。该研究考虑动静边界转换的影响,最后建立了具有黏弹性边界的螺旋桩-土体三维模型。探讨了处于海相软土场地下,不同种类地震波、地震强度、入射角度和螺旋叶片个数对螺旋桩轴力、弯矩和动力p-y曲线的影响。结果表明,相比较于弯矩,入射角度对轴力和动力p-y曲线的影响较大。除此之外,地震强度对弯矩的影响较大,而地震波频率和螺旋叶片个数对其影响较小。不同地面峰值加速度(0.05g,0.10g,0.30g)时,随着入射角度的改变,螺旋桩受到最大和最小弯矩的差值从144.1 N·m增加到了891 N·m。通过该研究结论,不仅可以得出软土场地下螺旋桩-土体的相互作用关系,也能为螺旋桩抗震设计提供依据。

可切换智能负载的T型三电平电力弹簧负载电压谐波含量和超调量研究

首次把单相T型三电平逆变器应用在可切换智能负载的电力弹簧中,降低了负载电压的谐波含量,建立了可切换智能负载的T型三电平电力弹簧的数学模型。并推导了传统载波调制对可切换智能负载的T型三电平电力弹簧直流侧中点电位的影响,引入了中点电位控制方案,结合积分分离控制思想得到了可切换智能负载的T型三电平电力弹簧的控制策略。该控制策略能有效降低负载电压在网侧电压波动时的超调量。最后,通过Matlab/Simulink仿真验证,在稳关键和非关键负载电压时,改进后的谐波含量降低了3.47%和1.65%,超调量降低了0.34%和0.1%。

某商用车钢板弹簧失效分析与结构优化

为解决某商用车钢板弹簧断裂问题,分别从板簧材质、成型工艺、结构设计强度多方面进行失效分析,考虑不同工况场景的载荷特点,建立板簧的非线性仿真模型。根据整车冲击工况加载标准,提取各工况下的板簧应力。建立板簧总成的详细模型,以提取的板簧应力为载荷,考察板簧及桥壳底板的可靠性,从而确定薄弱部位与断裂原因。以主簧的簧片厚度为设计变量,以板簧的结构应力为约束条件,以总质量最小为约束目标,对板簧进行尺寸优化,寻找满足应力要求的簧片最小厚度。对优化后的主、副簧进行疲劳耐久试验,验证仿真结果的准确性。

三相电力弹簧的无源控制策略研究

针对太阳能、风能等新能源设备大规模并入电网造成的电能质量下降问题,近年来出现了电力弹簧(ES)的概念。依据推导出的三相电力弹簧(TPES)的数学模型,搭建了对应的系统模型,依据无源控制(PBC)理论,分析了系统的无源性,并分别采用传统PI控制和无源控制验证了三相电力弹簧能够维持关键负载(CL)电压的稳定。通过仿真和实验验证,在有功功率变动工况下,无源控制的超调量远远低于PI控制的13.7%,调节时间0.03 s也低于PI控制的0.07 s,静差率0.0002%也小于PI控制的0.08%,表明无源控制的动态性能和静态性能都更出色。此外,相比于传统的PI控制,无源控制所需参数更少,控制系统结构更加简单。

基于微服务的多数据源目标接入展现技术研究

本文深入剖析了当前指挥信息系统态势目标展现中多数据源接入时暴露出的问题,设计了一种从服务底层到态势展现的整套架构,并从研发效率、系统性能对架构应用效果进行了比对。随着指挥信息系统信息化程度的不断提升,集中式服务管理模式逐渐显现系统并发性能受限、数据处理能力较弱、网络地理信息系统(WebGIS)元素展现方式混杂且开发效率低下等诸多不足,这些问题在很大程度上制约了目标态势展现场景应用的发展与创新。针对上述问题,本文提出了一种基于微服务的架构设计模式。这一技术将原本庞大的多数据源接入拆分成多个独立、轻量级的服务,设计提供了统一的展现服务架构,并通过解除各服务之间的耦合关系,避免了统一的、集中式服务管理机制带来的种种弊端。这种模式不仅提高了系统并发处理能力,同时增强了数据协作处理能力,使得多类元素能够以一种统一、高效的方式进行展现。

基于载荷谱的钢板弹簧耐久试验规范优化

文章以轻型客车的钢板弹簧为例,开展了基于试验场载荷谱的整车耐久试验规范优化。选取了能够表征钢板弹簧受力的板簧前端安装支座为载荷谱关键采集点,采集了试验场耐久规范的载荷谱,结合疲劳理论知识并通过N-code软件计算得到不同试验工况的伪损伤值。以保留原始载荷谱90%的伪损伤当量为目标生成了加速试验规范,进而从功率谱密度、统计值和雨流计数等方面对优化前后的耐久试验规范进行了分析和对比,结果表明,在保留原有试验规范的特征基础上可以实现明显的加速,试验周期缩短了60%。

浅析动车组转向架静压载试验调平影响因素

介绍了我国高速动车组转向架技术发展的历程,根据CRH1型动车组转向架静压载试验的具体要求,非常详细地分析了构架、轮径、弹簧组3个关键因素对转向架静压载试验的影响,并针对这些影响因素提出了具体调平措施。对于进一步提高静压载试验一次合格率具有较强的实际意义。

基于矿区运输的自卸车板簧承载强度分析

自卸车在矿区进行运输作业时,因路况复杂,存在重载上坡、下坡的情况,所以对悬架系统的刚度要求比较高。为保证矿区自卸车安全和稳定的行驶,通过对自卸车板簧的材质、承载、受力、路况等方面分析,计算板簧刚度、平均应力,辅助使用强度分析软件CATIA、Hyperworks、Optistruct进行数据建模,得出板簧强度在不同条件下的表现及满载载荷下各板簧推荐值,为其运营和维护提供理论参考。