汽车覆盖件逆向工程设计研究与应用

逆向工程在汽车覆盖件设计过程中得到了越来越广泛的应用.以某车型翼子板的逆向设计为例,采用数码摄影和光学扫描相结合的非接触式基于光学原理的ATOS & TriTop系统得到数据点,针对汽车覆盖件的特点,结合逆向工程软件Imageware,详细阐述了由大量数据点进行曲线、曲面反求的汽车覆盖件逆向工程设计方法.     

液驱混合动力车辆能量回收系统关键问题研究

液驱混合动力车辆通过双向液压变量马达排量的改变,将车辆的制动能储存在液压蓄能器中.因此,有必要对双向液压变量马达排量控制机构的响应特性和蓄能器在储能及放能过程中的能量损耗进行研究.建立了排量控制机构的模型,并通过实验得到了关键元件高速开关阀的所需参数,分析了影响响应特性的因素;建立了蓄能器与连接管路的数学模型,对储能和放能过程中的能量损耗影响因素进行了分析.所得结论对液驱混合动力车辆的设计和动态特性分析具有参考意义.     

Fluorescence Spectra and Luminescent Mechanism of Vitamin b Fmily Based on Solid Powder Direct Illumination

The simple approach to acquire the fluorescence spectra of vitamin b1,b2 and b6 is proposed by direct illumination on solid powder sample.The experimentally acquired fluorescence spectra are in accordance with the previous measurements on soluble samples.The fluorescence spectra for a mixture of vitamins b1,b2 and b6 with different concentrations have been investigated,and the fluorescence mechanism is explained on the basis of molecular structure.Possible reasons of the blue-shift of the fluorescence peak and enhancement of the peak power are explained as well.The advantages of solid powder method is analyzed and discussed.     

负半径滚子从动件盘形凸轮机构滚子作纯滚动条件的研究

以负半径滚子从动件盘形凸轮机构为研究对象,通过建立通用运动学条件模型,得到了关于该类直动、摆动从动件凸轮机构滚子作纯滚动的运动学条件.通过分别对从动件内、外圈进行力学分析,得到了关于直动、摆动负半径滚子从动件凸轮机构更具真实结构特点的滚子作纯滚动的力学条件.     

泵车泵送系统LabVIEW建模方法研究

LabVIEW软件是一种图形化的编程工具,人机交互界面方便且带有仿真与控制设计模块,可以进行系统的数学建模与仿真.为此,在深入研究某款THB38型号混凝土泵车液压系统工作原理的基础上,采用功率健合图与LabVIEW软件相结合方法建立了其泵送系统的数学建模,并进行了正常泵送和发生混凝土堵管故障两种工况下的仿真分析.仿真结果表明:该建模方式能满足仿真精度要求,可以用来方便地研究泵送系统故障发生前、后系统动态特性的变化,以便达到全面掌握混凝土泵车液压系统动态特性的目的.希望该建模方式对其他系统的建模能提供一些参考和指导.     

石英晶体成型机气动和控制系统设计

介绍了石英晶体成型机的工艺过程和工作原理,重点阐述了其气动系统和控制系统的设计内容.采用PLC和触摸屏为控制核心,以气缸为主要执行元件,保证了设备的可靠性和灵活性,具有较强的抗干扰能力.大量实践证明,该成型机运行平稳,操作灵活方便.     

散料研磨工艺对工件表面质量及材料去除率的影响

通过实验探讨了散料研磨过程中磨料种类、磨料粒度和研磨剂装入量等工艺参数对工件表面质量和材料去除率的影响.实验结果表明,随磨料粒度的增大,工件表面粗糙度值、残余应力和材料去除率增大;采用相同粒度磨料研磨,磨料的硬度越高,工件表面残余应力和材料去除率越大.硬度高、脆性大的磨料,可有效减小研磨表面粗糙度值;随研磨剂装入量的增大,表面残余应力减小.对工件表面粗糙度和材料去除率而言,研磨剂装入量有一最佳值,装入量过小或过大,均会降低工件表面质量和研磨效率.     

Experimental Investigation of Capacity Control Scheme on System Performance for a Machine Tool Cooler

Highly accurate manufacture in machining industry can only be obtained with precise temperature control of the coolant (oil or water).Machine tool with more accurate,stable and advanced the precision of the working component cannot be developed without appropriate cooling.However,the machine tool coolers are facing the control hunting of cooling temperature and the dramatic variation of heat load in high-accuracy machining.The main objective of this study is to evaluate the influence of the hot-gas by-pass scheme and suction regulation for capacity control of a machine tool cooler system.In this study,experimental investigation on both hot-gas by-pass scheme and suction valve regulation for capacity control has been proposed.Effects of using capillary tube and thermostatic expansion valve along with different capacity control scheme have been investigated extensively in an environmental testing room.Cooling performance and power consumption of the cooler system have been measured and analyzed as well by comparing with different opening percentage of throttling valve under specific coolant temperature.The experimental results reveal that the power consumption will reduce slightly by capacity control using the hot-gas by-pass scheme but the coefficient of performance (COP) of the overall system will decrease.Lower coolant temperature will result in higher compressor power consumption as well.While conducting suction valve regulating for capacity control,energy-saving at 10%-12% can be obtained by using thermostatic expansion valve under different evaporator load.It also reveals that suction valve regulation along with adequate choice of thermostatic expansion valve can provide alternative choice for steady capacity control and substantial energy-saving.The proposed cooler systems with different capacity control schemes are not only more cost-effective than inverter driven system,but also can perform energy-saving and precise temperature control specific for high-accuracy machine tool cooling.     

一种基于混合型结构优化算法——Apriori-Mend算法

关联规则挖掘是数据挖掘领域中最重要的研究问题之一。Apriori是关联规则挖掘的一种经典算法,它使用候选项集产生测试机制来找出所有满足用户最小支持度的项集,但它需要多次扫描数据库,会产生大量的候选项集。针对Apriori算法的不足,提出了一种基于混合型新的优化算法:Apriori-Mend算法。该算法从优化产生2项集、事务压缩等几个方面对Apriori算法进行优化,将散列技术应用于产生1项集和2项集,采用库优化策略和混合型存储结构,以节省空间和运算时间。实验结果表明,Apriori-Mend算法运行速度比Apriori算法有明显的提高。     

基于EZ-USB FX的DSP数据采集系统的设计

介绍数据采集理论,并设计了一种基于EZ-USB FX的DSP数据采集系统。该系统采用DSP和USB接口代替已往的单片机和系统总线式的传统数据采集系统,提高了系统数据处理能力和接口能力。最后简单介绍了基于USB的数据处理方式和该系统的技术特点。