聚类分析法在城市公交行驶工况开发中的应用

摘要：针对昆明市161路混合动力公交客车实际行车数据,使用K—Means聚类分析法对运动学片段进行了分类,并构建了161路的行驶工况．研究表明：K—Means聚类分析法获得的两类运动学片段特征明显,分别反映了较为通畅和十分拥堵的交通状况;构建的行驶工况可以代表161路的实际行驶工况,具有怠速时间长、平均车速低、加减速所占比例高和车辆启停频繁的特点．     

近场空爆载荷作用下船体板变形估算方法

鉴于目前我国舰船空中爆炸结构响应试验数据的匮乏以及对复杂结构采用理论求得解析解的困难,对船体板结构在空中近场爆炸载荷作用下的破坏估算方法进行研究.根据爆轰波理论及气体膨胀理论计算出空中近场爆炸载荷的形式及其正压作用时间,应用应力波及塑性动力学理论推导船体板结构的变形,得到不同空爆工况下船体板的破口大小及挠度.通过算例进行验证,计算结果与经验值良好吻合.所推导的估算方法应用于舰船结构在空中近场爆炸冲击波作用下产生的毁伤能够满足工程计算精度要求,可作为舰船防护结构的设计依据.     

驾驶员生理状态对驾驶行为差错的影响

根据驾驶行为的生理机制,建立了驾驶行为运动系统,并依据人的行为差错理论分析了驾驶行为过程中驾驶员的各种生理状态,以及生理状态导致的各种驾驶行为差错。通过分组调查470名驾驶员的生理状态导致的驾驶行为差错,应用主成份分析原理,得出驾驶员的生理状态对驾驶行为差错的影响。     

单极性SPWM逆变桥驱动方式研究

在工程实践中,单极性正弦脉宽调制（SPWM）逆变桥路具有多种驱动方式。理论分析、样机实验及软件仿真发现,不同的驱动方式造成了逆变桥臂单端输出波形、双端输出谐波上的差异。单臂斩波驱动时,桥臂中点的响应Ua为正半波不变、负半波抬高一个幅值的变异正弦波形,Ub为调制波频率的方波波形。双臂斩波驱动时,Ua和Ub呈现互差调制波半周期的正弦半波波形。就总的谐波系数（THD）而言,带同臂互补的驱动方式要优于不带同臂互补的驱动方式。通过研究这些差异,对在工程上正确合理地选择桥路的驱动方式无疑是有益的。     

太阳能光伏MPPT技术仿真研究与硬件电路设计

最大功率点跟踪(MPPT)技术是太阳能光伏发电系统的核心技术,如何进行快速、准确地跟踪,直接影响到整个光伏发电系统的性能。提出一种简单易行、快速、准确的最大功率点跟踪技术,并进行了仿真研究。最后对直流升压-逆变的两级拓扑结构设计的光伏逆变系统,进行了直流升压电路及其功率开关管IGBT驱动的硬件电路设计。驱动电路的测试结果表明,该驱动电路响应快、性能好、设计简洁,为MPPT技术的动态跟踪提供了有效的硬件基础。     

Experimental Investigation and Numerical Simulation of an Expanding Multifront Detonation Wave

Results of experimental investigations of an expanding multifront detonation wave are presented. Two stages of spontaneous formation of new disturbances and transverse waves on the expanding detonationwave front are observed. The main mechanisms of reinitiation of detonation waves are discussed. Twodimensional numerical simulation of the dynamics of a multifront detonation wave in a linearly expanding channel is performed. The effect of spontaneous formation of new disturbances and new transverse waves is confirmed by computations, and the main mechanism of multiplication of transverse waves is the instability of detonationwavefront elements at the stage they cease to be in the overdriven state and are attenuated during expansion.     

Interactions of Inert Confiners with Explosives

The deformation of an inert confiner by a steady detonation wave in an adjacent explosive is investigated for cases where the confiner is sufficiently strong (or the explosive sufficiently weak) such that the overall change in the sound speed of the inert is small. A coupling condition which relates the pressure to the deflection angle along the explosive-inert interface is determined. This includes its dependence on the thickness of the inert, for cases where the initial sound speed of the inert is less than or greater than the detonation speed in the explosive (supersonic and subsonic inert flows, respectively). The deformation of the inert is then solved by prescribing the pressure along the interface. In the supersonic case, the detonation drives a shock into the inert, subsequent to which the flow in the inert consists of alternating regions of compression and tension. In this case reverberations or ‘ringing’ occurs along both the deflected interface and outer edge of the inert. For the subsonic case, the flow in the interior of the inert is smooth and shockless. The detonation in the explosive initially deflects the smooth interface towards the explosive. For sufficiently thick inerts in such cases, it appears that the deflection of the confiner would either drive the detonation speed in the explosive up to the sound speed of the inert or drive a precursor wave ahead of the detonation in the explosive. Transonic cases, where the inert sound speed is close to the detonation speed, are also considered. It is shown that the confinement affect of the inert on the detonation is enhanced as sonic conditions are approached from either side.     

城市电瓶轿车驱动系统的研究

为进一步拓宽电动汽车开发的视野,促进我国电动汽车市场化、多样化的发展,在综合分析电动汽车的驱动结构基础上,提出了一种新的驱动机构,经理论分析和试验证明是可行的.