PMSM用逆变器单环矢量调制策略

分析了目前永磁同步电机（PMSM）常用控制方法的优点与不足,结合正弦波脉宽调制（SPWM）技术与转子磁场定向控制（FOC）技术,提出了一种PMSM用逆变器的单闭环空间矢量调制（SL—SVPWM）方法。以PMSM模型为基础,在Matlab仿真软件的Simulink环境下结合S函数构建了基于SL—SVPWM的PMSM伺服系统仿真模型。通过试验比较了SPWM与SL-SVPWM控制方式下绕组相电流波形,分析了SL—SVPWM驱动下电机的动态响应性能。由仿真与试验结果可见,SL-SVPWM与SPWM相比PMSM的控制性能更为优越,与FOC相比控制系统结构、算法大为简化。     

Integrating parking behaviour in activity-based travel demand modelling: Investigation of the relationship between parking type choice and activity scheduling process

Traditionally, the parking choice/option is considered to be an important factor in only in the mode choice component of a four-stage travel demand modelling system. However, travel demand modelling has been undergoing a paradigm shift from the traditional trip-based approach to an activity-based approach. The activity-based approach is intended to capture the influences of different policy variables at various stages of activity-travel decision making processes. Parking is a key policy variable that captures land use and transportation interactions in urban areas. It is important that the influences of parking choice on activity scheduling behaviour be identified fully. This paper investigates this issue using a sample data set collected in Montreal, Canada. Parking type choice and activity scheduling decision (start time choice) are modelled jointly in order to identify the effects of parking type choice on activity scheduling behaviour. Empirical investigation gives strong evidence that parking type choice influences activity scheduling process. The empirical findings of this investigation challenge the validity of the traditional conception which considers parking choice as exogenous variable only in the mode choice component of travel demand models.     

驻车制动力的检验方法分析

根据全国农用运输车统检的统计资料，以及车辆在上，下坡路面上驻车状态的受力分析，认为反力式制动试验台只具有单晌拖动能力，当以瓜力式制动试验台进行出厂检验和安全性能检测时，造成相反方向，驻车制动性能的全面漏检。     

一种新型自动舵控制策略研究

本文基于预测控制的基本思想,利用神经网络技术,提出了一种新型自动舵控制策略。仿真结果表明了其优良性能。     

我国大中城市机动车停放设施研究

车辆停放问题越来越受到大中城市交通主管部门和市民的关注,在分析目前我国城市机动车停放设施现状的基础上,结合国内外实践经验,提出修建立体式停车场是解决未来城市停车难问题的最佳途径。     

BIR制动器驻车力矩计算方法

盘式制动器以其制动性能好等优点被广泛应用于各种汽车上,文章对BIR制动器的驻车原理进行了详细分析,介绍了2种盘式制动器驻车力矩的计算方法,并通过某车型进行了实际验证,其结果是驻车制动力的总和大于该车在测试状态下整车质量的20％,满足法规要求,表明了算法的有效性。     

天津市内停车难原因剖析及对策研究

随着天津市机动车保有量逐年上升,停车位紧张,停车难已成为困扰天津市民有车一族的突出问题。基于对天津市部分停车设施现状的调查走访和对天津市民的问卷调查,了解天津市内停车问题现状,分析得出造成天津市停车难问题的主要原因,并提出了针对性的对策建议。     

正交试验设计在交通意向调查中的应用

为了在保证意向调查精度的基础上精简方案数量,采用正交的方法进行方案设计。文中简要介绍了正交设计的原理,利用因素间的正交特点进行多因素多水平的方案组合,并比较了应用正交设计前后的效果。该方法降低了组合次数,也有利于提高后期数据处理的工作效率。在调查实例中,运用正交设计的停车行为意向调查问卷取得了较好的效果。     

联合机动编队兵力配置冲突消解

联合机动编队兵力配置是攻防作战的前提,众多兵力同时配置产生的冲突制约编队战斗力的发挥。着眼于联合机动编队整体作战效益,对联合机动编队兵力配置中的冲突消解问题展开研究。在分析联合机动编队兵力配置冲突产生原因的基础上,确定消解冲突的原则,针对联合机动编队兵力配置中的典型冲突问题提出消解方法,为解决联合机动编队兵力配置中的冲突问题提供思路。     

The effects of on‐street parking on the service rate of nearby intersections

An on‐street parking maneuver can often start a temporary bottleneck, leading to additional delay endured by the following vehicles. If the maneuver occurs near a signalized intersection, the service rate of the intersection might be reduced. In this paper, a model is built to analyze the effects of parking maneuvers on the intersection service rate. Based on the hydrodynamic theory of traffic flow, the perturbation caused by the parking maneuver is analyzed. Using dimensional analysis, we illustrate the relation between the background conditions, the distance from the parking area to the intersection, and the intersection service rate. Based on this relation, one can compute the service rate reduction caused by existing on‐street parking areas. A minimum distance between the parking area and the intersection to avoid such reduction can be accordingly found. Numerical examples based on empirical data from the city of Zurich, Switzerland, are provided to illustrate the practical applications. Although the analysis is based on streets with a single lane per direction, the findings can provide some insights regarding different situations. We hope such findings can be used as a basis for developing on‐street parking design guidelines. Copyright © 2015 John Wiley & Sons, Ltd.