Inertia Matching During Dynamic Simulation of Vehicle Drive System on Test Bench

Framework and basic parameters of a test bench for motor drive system of electric vehicle (EV) are illuminated. Two kinds of electric drive models, one was for the electric vehicle drived on real road, the other was for that on test bench, are put forward. Then, dynamic analysis of these models is made in detail. Inertia matching method of the test bench is researched and some useful formulas and graphs are brought forward. The experiment of an electric bus is introduced in order to explain the usage of this inertia matching method.

Electronic Unit Pump Test Bench Development and Pump Properties Research

A unit pump test bench is developed on an in-line pump test platform. The bench is composed of pump adapting assembly, fuel supply subsystem, lubricating subsystem and a control unit. A crank angle domain injection control method is given out and the control accuracy can be 0.1° crank degree. The bench can test both mechanical unit pump and electronic unit pump. A test model-PLD12 electronic unit pump is tested. Full pump delivery map and some influence factors test is done. Experimental results show that the injection quantity is linear with the delivery angle. The quantity change rate is 15% when fuel temperature increases 30 ℃. The delivery quantity per cycle increases 30 mg at 28 V drive voltage. The average delivery difference for two same type pumps is 5 %. Test results show that the bench can be used for unit pump verification.

A versatile test bench for photomultiplier tube characterization and its application in the DAMPE-PSD

Performance characterization for massive photomultiplier tubes(PMTs) is a frequently encountered procedure in large nuclear and particle experiments.To facilitate this work,a dedicated test bench system has been developed at the Institute of Modern Physics,Chinese Academy of Sciences.The two-dimensional photocathode position scanning capability is an intrinsic function of the test bench,and up to 25 PMTs,with the diameter smaller than 2",can be tested simultaneously.The parameters of the light source pulses can be adjusted in a wide range,thus making it suitable for various characteristics measurements.The test bench system is highly automated with all the controlling operations integrated into a single software.Additionally,the hardware platform is extensible which allows complex testing schemes,and the modularity in the software design makes the migration from one testing configuration to another light-weight and efficient.All these features make the test bench versatile and reusable in different experiments.It has been first used in the construction of the Plastic Scintillator Detector(PSD) of DArk Matter Particle Explorer(DAMPE),and a total of 570 Hamamatsu R4443 tubes were tested successfully.The performance was verified and the testing results are also reported in this article.

Laboratory Test Bench for Research Network and Cloud Computing

At present moment, there is a great interest in development of information systems operating in cloud infrastructures. Generally, many of tasks remain unresolved such as tasks of optimization of large databases in a hybrid cloud infrastructure, quality of service (QoS) at different levels of cloud services, dynamic control of distribution of cloud resources in application systems and many others. Research and development of new solutions can be limited in case of using emulators or international commercial cloud services, due to the closed architecture and limited opportunities for experimentation. Article provides answers to questions on the establishment of a pilot cloud practically “at home” with the ability to adjust the width of the emulation channel and delays in data transmission. It also describes architecture and configuration of the experimental setup. The proposed modular structure can be expanded by available computing power.

Research on cooling-temperature control strategy of fuel-cell engine test bench

As one of the important ways to utilize hydrogen energy,fuel cells are receiving more and more attention and research from countries and institutions.To meet the practical needs of testing the performance of high-power fuel-cell systems and simulate the actual application environment as much as possible,a fuel-cell system test bench is usually used to test the system performance,in which the cooling-temperature control of the test bench has a great impact on the results of the performance of the fuel-cell system.This paper studies the cooling-temperature control strategy of a 150-kW-class fuel-cell engine test platform,proposes a new test-bench cooling-system structure with a thermostat and heat exchanger as the main heat-dissipation components,and compares and analyzes the impact of coordinated thermostat and heat-exchanger control on the fuel-cell system test performance.The test results show that the control strategy of the coordinated operation of a thermostat and heat exchanger can maintain the steady-state error to within±0.3℃and maintain the temperature variation to within±1.5℃during the loading-condition test,so as to avoid the limitation of system output performance due to excessive cooling-temperature fluctuation and ensure that the fuel-cell engine performance-test process is carried out smoothly and efficiently.

Changes in coronary bifurcations after stent placement in the main vessel and balloon opening of stent cells:theory and practical verification on a bench-test model

Objective To describe changes that occur in stent morphology and structure after its implantation in coronary bifurcation.Side branch (SB) compromise after stenting of main vessel in coronary bifurcation is a major intraprocedural problem and for the long term,as a place of restenosis.Methods We created an elastic wall model (parent vessel diameter 3.5mm,daughter branches 3.5mm and 2.75mm)with 30,45 and 60 degree distal angulation between branches.After stent implantation,struts to the side branch were opened with 2.0mm and consequently 3.0mm diameter balloons.Subsequent balloon redilatations and kissing balloon inflations (KBI) were performed.All stages of the procedure were photographed with magnification up to 100 times.Results We found that the leading mechanism for side branch compromise was carina displacement,and discovered theoretical description for expected ostial stenosis severity.Based on our model we found that displacement of bifurcation flow divider cause SB stenosis with almost perfect coincidence with our theoretical predictions.Opening of stent cells through the proximal and distal stent struts always increased interslrut distance,but never achieved good apposition to the wall.Balloon diameter increase didn't give proportional enlargement in stent cell diameters.KBI leads to some small better stent positioning,correcting main vessel strut dislodgment from wall,but never gave full strut-wall contact.Distance between struts and wall was minimal only when the stent cell perfectly faced ostium of SB.This was also our observation that the shape of ostium of SB becomed eUiptically-bean shaped after stent implantation and generally kept that shape during consequent stages of experiment.Measured diameter and area stenosis were perfectly fitted and theoretically predicted from our concept Conclusion We have described stent-wall deformations in stent-balloon technique for treatment of coronary bifurcation demonstrating carina displacement as possibly main mechanism of side branch compromise after main vessel stenting.We have shown that KBI could not give full strut-wall contact if there is no perfect facing of stem cell and SB ostium.(J Geroatr Cardool 2008;5(1):43-49)

Bench Test Modeling for Current and Future PCMO Fuel Economy Requirements

The automotive and lubricant industries have been placing increased emphasis on the fuel economy benefits of today′s modern passenger car motor oils.The current ILSAC GF-4 specification has more stringent requirements than previous ILSAC specifications,and the proposed future ILSAC GF-5 specification is looking at further improvements in the lubricant′s fuel economy performance.To address these needs,Afton Chemical has developed correlations between the rheological and frictional properties of oils and fuel economy measured in engine and field tests.In this paper we will present correlations between lubricants′ physical properties and fuel economy measured in vehicles and engine tests.These tools have been used to develop current commercial oils which are being used extensively to meet today′s OEM needs.

Study of the Judder Characteristics of Friction Material for an Automobile Clutch and Test Verification

The friction judder characteristics during clutch engagement have a significant influence on the NVH of a driveline.In this research,the judder characteristics of automobile clutch friction materials and experimental verification are studied.First,considering the stick-slip phenomenon in the clutch engagement process,a detailed 9-degrees-of-freedom(DOF)model including the body,each cylinder of the engine,clutch and friction lining,torsional damper,transmission and other driveline parts is established,and the calculation formula of friction torque in the clutch engagement process is determined.Second,the influence of the friction gradient characteristics on the amplification or attenuation of the automobile friction judder is analyzed,and the corresponding stability analysis and the numerical simulation of different friction gradient values are carried out with MATLAB/Simulink software.Finally,judder bench test equipment and a corresponding damping test program are developed,and the relationship between the friction coefficient gradient characteristics and the system damping is analyzed.After a large number of tests,the evaluation basis of the test is determined.The research results show that the friction lining with negative gradient characteristics of the friction coefficient will have a judder signal.When the friction gradient value is less than-0.005 s/m,the judder signal of the measured clutch cannot be completely attenuated,and the judder phenomenon occurs.When the friction gradient is greater than-0.005 s/m,the judder signal can be significantly suppressed and the system connection tends to be stable.

俯仰式播种单体仿形性能检测试验台设计与试验

为解决播种单体仿形机构性能难以检测的问题,设计了俯仰式播种单体仿形性能检测试验台。阐述了试验台组成结构与工作原理,对其高速传动系统、液压升降系统、监控系统以及关键部件参数进行设计。应用ANSYS软件对台架整体和关键部件进行静力学分析和模态分析,验证结构设计的合理性。为检验俯仰式播种单体仿形性能检测试验台的实际检测效果,以德邦大为1205型牵引式免耕精量播种机播种单体为研究对象,先以液压杆伸出量与传送带速度为试验因素,以监控系统误差为评价指标进行试验。试验得出,在液压杆伸出量为0~200 mm范围内,监控系统角度传感器最大误差为0.69 mm;在传送带速度8~19 km/范围内,光电编码器最大误差为0.18 km/h。确认监控系统准确性后,再以单体速度为试验因素,采集速度8、10、12 km/h下地块的起伏数据为目标曲线,以地形起伏模拟曲线的绝对误差平均值为指标进行单因素试验,试验得出,所设计的试验台可有效模拟田间地面的起伏频率与起伏量,绝对误差平均值为1.86 mm,满足播种单体仿形性能检测需求。

无线射频压裂滑套系统模拟试验研究

将无线射频识别(RFID)技术应用到油水井压裂中,能够很好地解决现有压裂滑套存在的压裂级数受限、操作非智能等诸多问题。因井下工况复杂,理论分析与实际应用差别较大,为进一步系统地探究井下无线射频系统的开发应用,使用三维软件设计无线射频滑套模拟试验台,对标签的运动状态进行理论分析,并建立室内模拟试验平台,系统地进行井下相关试验。试验结果表明:标签选择有铁氧体磁芯,且天线绕制形式选用单层螺线管线圈,可以提高整个系统的性能;在系统电感值相同的情况下,单层螺线管天线轴向长度对阅读器模块能识别的标签最大通过速度有积极的影响;标签天线线圈与阅读器天线线圈平面之间的角度也会影响标签的识别率。研究结果对井下无线射频系统的开发应用具有一定的指导作用。

基于滑模扰动观测器的阀门开度预测控制

针对电动阀门在运行过程中,由于外部干扰、系统参数变化、摩擦力等非重复干扰的影响而难以达到高精度控制的问题,提出一种基于滑模扰动观测器的预测控制方法。通过对阀门驱动原理进行深入研究,构建阀门的数学模型,根据模型中电机电流与总负载扰动的正相关性,以电机电流、阀门转速为输入量,采用滑模扰动观测器对系统总负载扰动进行估计。设计模型预测控制器,对扰动估计值进行补偿,实现对阀门开度控制的准确性,鲁棒性以及对总扰动值跟踪的快速性。理论分析、仿真和试验表明:观测器仅0.001 s便跟踪到了设定值,收敛速度快,阀门开度精度误差在0.2%以内,完全达到控制目标,开度控制效果良好。可充分验证该控制方法在不同的负载扰动下,依然能使电动阀门保持良好的开度控制精度以及抗扰动能力。

钵苗移栽机取苗装置的设计与试验

设计了一种钵苗移栽机取苗装置,并对夹苗和松苗两种状态下的末端执行器进行运动仿真,从而选择合适行程的气缸或推杆作为原动件。选用凸轮机构用于顶苗,根据凸轮各阶段工作规律设计出合理的轮廓线,利用仿真验证出满足设计要求。试验结果表明:设计的取苗装置未取出率平均值为8.22%,取苗成功率平均值为91.78%,达到了设计目标。

基于扩张状态观测器的伺服加载模糊滑模控制

针对电动伺服加载测试台存在的间隙、摩擦等非线性控制问题,以滑模变结构控制(SMC)为主体进行了加载控制器设计。分析伺服加载测试台整体结构,提出一种基于扩张状态扰动观测器(ESO)的模糊滑模控制(FSMC)策略。该策略在使用ESO针对伺服加载系统的外部干扰进行观测的基础上,设计了模糊控制对滑动模态面和滑模趋近律进行自适应调节,提高了系统的动态实时跟随能力和干扰补偿能力,并减小SMC控制器稳定时的抖振现象。仿真结果表明:所设计的基于扩张状态观测器的模糊滑模控制器(FSMC-ESO)对比传统SMC及PID控制具有更好的快速响应性和鲁棒性。

电涡流缓速器优化设计与制动性能分析

文章在考虑去磁效应的基础上建立电涡流缓速器数学计算模型,采用涡流折算系数法求出闭合磁路磁感应强度,推导出电涡流缓速器电磁制动力矩表达式;在某汽车制动系统有限公司现有产品的基础上,将圆形极柱优化设计为扇形极柱,并利用Maxwell有限元仿真软件对不同长度扇形极柱的新型电涡流缓速器模型的制动力矩进行仿真分析;将最终确定的新型电涡流缓速器通过有限元仿真和台架实验与原产品进行对比验证。结果表明:新型电涡流缓速器与传统电涡流缓速器的制动扭矩在不同转速下变化的规律基本一致,制动性能有明显提升;仿真结果和实验结果最大误差小于5%,证明了新型电涡流缓速器的有效性和优化设计的正确性。

试验环境的盘式制动器NVH特性研究

文中采用多体动力学和声学边界元等数值方法,研究某盘式制动器试验条件下的NVH(Noise,Vibration,Harshness)特性。首先,建立试验环境的制动器刚柔耦合模型,从结构、激励源和传递路径3个方面分析制动NVH特性影响因素;然后,运用声学边界元法仿真得到制动振动辐射的噪声,并与台架试验结果进行比较。结果表明:制动盘第2~5阶轴向模态,支架第2~3阶轴向模态,以及制动钳和连接板第1阶轴向模态等模态固有频率与台架试验噪声频率较接近,可能引起共振而产生制动噪声;在不影响制动性能的前提下,改变制动盘与摩擦衬片阻尼系数能改善制动NVH特性;悬架螺旋弹簧下端振动大,减振器与衬套对振动具有显著衰减作用;由仿真声压级云图发现,制动盘与摩擦片接触部位声压级最大,且随频率增加呈先增后减趋势,与台架试验对应测点的噪声结果进行直接比较,两者趋势一致。

挖掘机多路阀试验与仿真分析

首先,设计了挖掘机多路阀台架试验方案,多路阀试验台架的主要单元组成包括动力源单元、模拟负载单元、控制系统单元等,本实验台架可对多路阀的流量特性、压力损失特性、主安全阀的二次升压特性、保持阀的启闭特性、逻辑阀的流量分配特性、再生特性等进行试验。然后,试验了多路阀的左直线行走滑阀在空载时的流量特性。最后,对比分析了多路阀左直线行走滑阀的试验数据和仿真数据,得出以下结论:(1)在台架试验中,传感器的选型、布置位置都对试验结果有影响;(2)全方位地对比了左直线行走滑阀的试验数据和仿真数据,其模型精度在90%以上。高精度的仿真模型可进一步优化分析左直线行走滑阀的性能。

基于电动汽车制动安全检测的短时工况及方法研究

常规的制动安全检测通常采用长时间、极端工况,但可能会失去准确的工作范围。针对这一不足,首先提出一种踏板稳定模式的短时工况试验方法,该方法结合了现有的测试标准,并不限于单一的极端制动模式,而是可以考虑电动汽车的快速稳态运行。在此基础上,基于机器学习对运行片段回归并通过连续拼接构建短时工况。利用短时工况提出一种改进的制动安全检测方法,该方法通过主成分分析对制动片段的特征参数进行降维,同时根据特征参数计算制动片段的重复性距离判断安全隐患。最后,通过在测试台架上跟随短时工况,验证所提出的短时工况和制动安全检测方法的有效性。

基于用户需求导向的智能座舱柔性试验台概念设计集成方法

为解决传统座舱试验台结构同质化及模块化设计不足等问题,采用亲和图法整理了汽车故障及用户初始需求;采用模糊Kano模型进行需求指标权重计算,并结合质量特性要素进行用户核心需求汇总;通过功能分析系统技术(Function Analysis System Technique,FAST)黑箱模型将用户需求转化为功能需求,并引入公理设计(Axiomatic Design,AD)理论与功能-行为-结构(Function-Behavior-Structure,FBS)模型进行逐级映射,最终确定智能座舱柔性试验台的结构设计要素。该设计过程以用户核心需求为导向,通过FAST-AD-FBS集成方法的应用,克服了传统产品概念设计中用户需求与产品功能结构设计间存在矛盾的问题,为提高产品创新设计的完整性及准确性提供了理论参考。