基于Pro/E的发动机配气机构参数化设计

本设计利用Pro/E的二次开发工具对直接驱动、双凸轮轴上置式配气机构进行了参数化建模.利用在大型产品建模中应用非常广泛的骨架功能,搭建了配气机构的骨架模型,并根据骨架模型创建和装配各元件,成功实现了此配气机构结构与尺寸的参数驱动.通过修改参数值,就可以生成一簇在结构形式上相似的配气机构模型.该方法大大提高了设计人员的工作效率,缩短了开发周期.     

基于层次实时有色Petri网的实时系统建模与分析方法研究

Petri网是一种基于图形进行模拟和分析的数学工具,能够描述系统的异步和并发行为,但是现有高级Petri网不能对嵌入式实时系统进行完整的模拟与实时性分析。该文首先通过扩展有色Petri网提出了层次实时有色Petri网模型,然后描述了嵌入式实时系统的建模和实时性分析方法。最后,将该文提出的方法应用于硬实时系统列车通信网络MVB总线控制器的建模和实时性分析过程,仿真和分析结果表明,该方法能够满足列车通信网络系统设计对MVB总线控制器的功能验证和实时性分析需求。     

刹车分泵内孔表面缺陷涡流探伤设备

刹车分泵是汽车的重要安全件。为控制刹车分泵内孔表面质量,提出采用涡流旋转探头检测方法,研制出一套半自动涡流旋转探头分泵内孔表面缺陷探伤设备。详细论述了涡流探头、机械传动和仪器控制等设备组成。实践应用表明,设计的探伤设备能够检出内表面0.5 mm孔状缺陷,信噪比〉8 dB,检测速度为4只/min,满足刹车分泵质量检测要求。同时该套检测装置还可应用于其它汽车零部件表面缺陷的检测。     

基于模糊神经网络的铁路车辆热轴等级判别模型

判别模型。该模型选定了温升、列温升差、辆温升差3个特征作为输入量,4种热轴等级作为输出量,并利用125条模糊推理规则和学习算法对模糊神经网络进行训练,得到的模糊神经网络可作为专家系统对热轴进行判别。实例仿真结果表明:模糊神经网络热轴判别模型使得判别参数减少,判别科学化,且判别的一致率达到95%。     

浅谈企业物资“零库存”管理的思路

物资"零库存"管理是企业在采购活动中,建立不同层次的供应商网络,从实施"零库存"管理的可行性分析、供需模式、作用和考虑因素等可以看出,"零库存"采购管理模式会给企业带来更好的效益.     

Continuous measurement of interaction forces between wheel and rail

Oscillatory wheel load fluctuation of considerable amplitude is always observed in railway cars traveling at high speed. This paper describes a continuous method for measuring the derailment coefficient and the forces between the wheel and rail. The acceleration measured on the axle box indicates that the frequency of this fluctuation can be as high as 70 Hz. Continuous measurement of wheel load using conventional methods is not possible due to this high frequency phenomenon. We have developed a new method for continuous measurement of these forces and the derailment coefficient using two pairs of strain gauge bridges with output phases shifted by 90°, and summing their outputs with a weighting function. This method works for measuring the forces between wheel and rail at high frequencies.     

On-line and off-line wheel/rail contact algorithm in the analysis of multibody railroad vehicle systems

An on-line and off-line hybrid contact algorithm for modeling wheel/rail contact problems is developed based on the elastic contact formulation. In the hybrid algorithm developed in this investigation, the off-line tabular search is used for predicting the location of tread contact points, while the on-line iterative search is used for predicting flange contact points. By so doing, a computationally efficient procedure is achieved while keeping accurate predictions of contact points for severe contact scenarios such as sharp curve and turnout negotiations. The use of the proposed hybrid algorithm can eliminate the time-consuming on-line iterative search for the second points of contact. Since the location of the second point of contact is pre-computed by the contact geometry analysis, the occurrence of two-point contact can be predicted by using the look-up table at the one-point contact configuration. A flange climb simulation demonstrates that the proposed hybrid contact search algorithm can be effectively used for modeling wheel/rail contacts in the analysis of general multibody railroad vehicle systems. This paper was presented at the 4th Asian Conference on Multibody Dynamics(ACMD2008), Jeju, Korea, August 20–23, 2008. Hiroyuki Sugiyama received his Ph.D. from the University of Illinois at Chicago in 2005. Dr. Sugiyama is currently an Assistant Professor at Tokyo University of Science, Tokyo, Japan. His research interests include the development of computer formulations for contact problems in vehicle systems and the large deformation problems of constrained multibody systems. Kohei Araki received his BS degree in Mechanical Engineering from Osaka City University in 2006. Mr. Araki is currently a Master’s student at Osaka City University, Osaka, Japan. His research interest is in the modeling of wheel/contact problems in railroad vehicle dynamics. Yoshihiro Suda received his Doctoral degree from the University of Tokyo in 1987. Dr. Suda is currently a Professor at the University of Tokyo, Tokyo, Japan. His research interests are in the dynamics of railroad vehicles and automobiles, in-telligent transportation systems (ITS) and personal mobility vehicles. He is currently serving as an Associate Editor of the IMechE Journal of Multi-Body Dynamics.     

基于垂向性能研究的新型悬架参数设计

设计了一种用于四轮独立转向独立驱动电动轿车的独立悬架,该悬架采用双横臂、螺旋弹簧结构,悬架连接带轮毂电机的大质量电动车轮。对悬架系统进行简化,建立了悬架二自由度振动模型,采用均方根值分析方法,计算出振动系统的频率响应函数及振动响应的均方根值(包括车身加速度均方根值、车轮相对动载荷均方根值及悬架动挠度均方根值),基于悬架参数对电动车辆垂向性能的研究,提出了新型悬架弹簧刚度和减振器阻尼系数的设计方法,结合仿真及实验验证了设计方法的合理性。     

汽车主动空气阻力制动系统仿真研究

针对汽车防抱制动时地面制动力存在极限值无法更有效的缩减制动距离问题,提出了新型汽车主动空气阻力制动(APB)系统,分析其工作原理并进行控制模型基础仿真研究。阐述主动空气阻力制动系统理论可行性,依据压缩空气喷气助力原理的反作用应用于汽车制动系统,利用MATLAB/Simulink建立新型汽车制动系统动力学模型和APB仿真模型。设计了仿真试验,对比实施APB控制的车速与轮速曲线,试验结果表明APB控制达到缩减制动距离和制动时间的目的。