汽车空调系统性能优化研究

为优化某车型空调系统性能,本文通过环境模拟试验、系统台架试验、零部件台架试验手段,从鼓风机、蒸发器、膨胀阀匹配等方面提出性能提升方案。改进后的空调系统呼吸点温度在前20min与改进前相比较降低了6~7℃,优化方案实施效果良好。     

A comparison between two pneumatic suspension architectures

The aim of this work is to assess and compare the mathematical models of two pneumatic suspension architectures and show how they can converge, after appropriate simplifications, to a general linear form. After making this model dimensionless, it will be used to study, with a transmissibility analysis, the behaviour of a mono-suspension (quarter-car model). Finally, an example of a design process will be shown to highlight the strengths and weaknesses of both architectures and to provide the reader with a practical design tool.     

基于组合式BP网络的空压机故障诊断

针对空压机故障诊断过程中参数的多样性及复杂性,分别采用单BP网络和组合式BP网络两种方法对其主要故障进行建模和诊断。结果表明:采用组合式BP网络的故障诊断方法更加简单实用,能有效地提高空压机故障诊断的准确率。     

空气悬架客车平顺性仿真与实验研究

以某大客车为研究对象，分别拟合前后悬架空气弹簧刚度，在Matlab中建立八自由度整车模型，并进行平顺性仿真与实验，将其仿真结果与试验结果进行比较，结果显示，所建立的动力学模型及仿真结果是正确的。     

基于滤波器分解的图像插值算法

本文研究了一种空域中的图像分解技术，进而利用改种分解方法，探讨了图像插值算法。本文提出的图像分解方法的主要思想是：利用类型确定的滤波器（如低通）对原始图像滤波，将图像分解为高频和低频两部分，并对分解得到的低频或高频成分进行处理，图像可分解成不同频率分量的图层之和，进而在各个图层一L进行相应的插值处理，最后利用逆变换得到最终的结果。     

机车车辆通风用新型空气过滤器的研制

对机车车辆通风用的传统空气过滤器存在的问题进行分析,介绍一种适合机车车辆通风用新型空气过滤器的结构特点、过滤机理、主要性能及试验情况等。     

铁路客车空调新风量和制冷量的自动调节

提出了通过采用新风量和制冷量综合自动调节办法,控制车内CO2浓度和温度,提高车内空气品质,满足乘客热舒适要求。     

Effects of the guideway's vibrational characteristics on the dynamics of a Maglev vehicle

The levitation control system in an electromagnetically levitated vehicle controls the voltage in its winding to maintain the air gap, which is the clearance between the electromagnet and the guideway, within an allowable range of variation, while strongly interacting with the flexible guideway. Thus, the vibrational characteristics of the guideway play an important role in the dynamics of Maglev (magnetically levitated) vehicles that utilise an active electromagnetic suspension system. In this study, the effects of the guideway's vibrational characteristics, such as natural frequency and damping, on the dynamics of the Maglev vehicle UTM-02 are numerically and experimentally analysed. From these analyses, the coupled equations of motion of the simplified vehicle–guideway model with three degrees of freedom are derived. Eigenvalues are calculated and frequency response analysis is also performed, in order to obtain a clear understanding of the dynamic characteristics resulting from the guideway's vibrational characteristics. To verify the numerical results, air gap tests of the urban Maglev vehicle UTM-02 are also carried out. These results lead us to recommend that the natural frequency of the guideway be decreased by increasing mass density rather than by decreasing rigidity, and that its damping ratio be increased in the Maglev vehicle UTM-02 employing a five-state feedback control law as a levitation control law.     

有源滤波器改进控制方法的仿真研究

有源滤波器通常采用常规的三角载波调制PWM控制方法，具有开关频率固定、输出波形谐波分量较少的优点，但响应速度比较慢、精度低。通过增加输入电压补偿来改进三角载波调制的PWM控制方法，可以提高有源滤波器的补偿精度和实时性，减少开关损耗。MATLAB/Simulink仿真验证了改进方案的可行性。     

轨道不平顺激励下车辆-桥梁垂向随机振动方差解法

提出时滞多维非白噪声轨道不平顺激励下车辆-桥梁垂向随机振动的时域分析方法。采用白噪声滤波法模拟单轮对下的不平顺,在宽频带内识别滤波器参数以实现波长选择功能。基于Pade近似构造累次时滞滤波器以反映各轮对下不平顺之间的时滞关系。结合成型和时滞滤波器,构造以一致白噪声为输入、时滞多维非白噪声不平顺为输出的合成滤波器。建立车辆-桥梁垂向振动模型,并与合成滤波器联立得到一致白噪声激励下的车-桥-滤波器扩阶状态方程。继而提出求解此扩阶时变系统随机振动方差响应的递推算法。算例结果与MonteCarlo模拟法符合良好,表明该方法具有足够的精度,且对时间步长不敏感。