多目标多重运输调度问题的混合算法

本文研究了多目标多重运输调度问题．建立了该问题的目标规划模型，提出了该问题基于分校定界和割平面技术的混合算法。     

结合一例工程浅谈桥头跳车的处理与防治

根据已建成通车的道路使用情况，系统分析桥头产生跳车的原因，同时提出一些处治方法。     

汽车助力转向系统异响问题分析研究

以某A0级轿车助力转向系统为研究对象,阐述了排查汽车转向系统异响问题的一般方法,之后对转向系统内关键部件的结构进行了分析,最后对各关键部件异响的形成机理进行了研究,形成了分析排查电动转向系统异响的一般流程,具有一定的参考意义。     

施工机群配置对温度离析的潜在影响

以沥青砼路面施工机群配置理论为基础,结合我国当前沥青砼路面施工工艺,分析了温度离析产生的主要原因,提出了从机群配置来缓解温度离析的主要措施和基于温度离析的机群配置评价标准.     

Software-in-the-loop development and validation of a Cornering Brake Control logic

In this article, a logic for vehicle dynamics control during partial braking while turning a corner is presented, which only requires knowledge of the instantaneous speed of the four wheels. For this reason, the proposed control algorithm can be adopted on all ABS equipped cars. A scheme of the simulation program for logic validation is described, which is constituted by a loop of software models of the principal vehicle subsystems which are singly illustrated. The proposed logic has been tested both in closed and open-loop maneuvers. The results are provided in the form of time histories of the principal analyzed quantities. The analysis of the results confirms the goodness of the proposed control strategy.     

芜湖长江大桥裕溪河桥车桥耦合振动分析

采用空间杆系有限元方法,建立芜湖长江大桥裕溪河2×80 m连续钢桁梁桥的动力分析模型。计算得到其横向基频为2.097 Hz,与实测值1.95 Hz吻合良好,且满足现行《铁路桥梁检定规范》相应限值1.125Hz的要求。运用车桥空间耦合振动理论对该桥在实际运营列车作用下的车桥动力响应进行计算与分析,结果表明,在空载及空重混编货物列车以速度50~80 km.h-1通过时,桥梁的横向振幅达到4.5~8.1 mm,与实测值4.6~8.4 mm吻合良好,但超出《铁路桥梁检定规范》的限值,而脱轨系数小于0.8,轮重减载率小于0.6;当通过速度在70 km.h-1以下时,机车车辆平稳性达到“良”或“合格”。因此,该桥能够满足空载及空重混编货物列车以70 km.h-1及以下速度通过。     

Modeling techniques for periodic vehicle routing problems

This paper presents a continuous approximation model for the period vehicle routing problem with service choice (PVRP-SC). The PVRP-SC is a variant of the period vehicle routing problem in which the visit frequency to nodes is a decision of the model. This variation can result in more efficient vehicle tours and/or greater service benefit to customers. We present a continuous approximation model to facilitate strategic and tactical planning of periodic distribution systems and evaluate the value of service choice. Further, results from the continuous model can provide guidelines for constructing solutions to the discrete PVRP-SC.     

Large motion mountain biking dynamics

A bond graph model of a mountain bike and rider is created to develop baseline predictions for the performance of mountain bikes during large excursion maneuvers such as drops, jumps, crashes and rough terrain riding. The model assumes planar dynamics, a hard-tail (front suspension only) bicycle and a rider fixed to the bicycle. An algorithm is developed to allow tracking of a virtual tire-ground contact point for events that separate the wheels from the ground. This model would be most applicable to novice mountain bikers who maintain a nearly rigid relationship between their body and the bicycle as opposed to experienced riders who are versed in controlling the bicycle independent of the body. Simulations of a steep drop are performed for various initial conditions to qualitatively validate the predictions of the model. Results from this model are to be compared to experimental data and more complex models in later research, particularly models including a separate rider. The overarching goals of the research are to examine and understand the dynamics and control of interactions between a cyclist and mountain bike. Specific goals are to understand the improvement in performance afforded by an experienced rider, to hypothesize human control algorithms that allow riders to perform manoeuvres well and safely, to predict structural bike and body forces from these maneuvers and to quantify performance differences between hard-tail and full suspension bicycles.     

Optimization and integration of ground vehicle systems

This article deals with the optimal design of ground vehicles and their subsystems, with particular reference to 'active' safety and comfort. A review of state-of-the-art optimization methods for solving vehicle system design problems, including the integration of electronic controls, is given, thus further encouraging the use of such methods as standard tools for automotive engineers. Particular attention is devoted to the class of methods pertaining to complex system design optimization, as well as approaches for the optimal design of complex systems under uncertainty. Some examples of design optimizations are given in the fields of vehicle system dynamics, powertrain/internal combustion engine design, active safety and ride comfort, vehicle system design and lightweight structures, advanced automotive electronics, and smart vehicles.     

A discrete optimization approach for locating Automatic Vehicle Identification readers for the provision of roadway travel times

This paper develops an algorithm for optimally locating Automatic Vehicle Identification tag readers by maximizing the benefit that would accrue from measuring travel times on a transportation network. The problem is formulated as a quadratic 0–1 optimization problem where the objective function parameters represent benefit factors that capture the relevance of measuring travel times as reflected by the demand and travel time variability along specified trips. An optimization approach based on the Reformulation–Linearization Technique coupled with semidefinite programming concepts is designed to solve the formulated reader location problem. To illustrate the proposed methodology, we consider a transportation network that is comprised of freeway segments that might include merge, diverge, weaving, and bottleneck sections. In order to derive benefit factors for the various origin–destination pairs on this network, we employ a simulation package (INTEGRATION) in combination with a composite function, which estimates the travel time variability along a trip that is comprised of links that include any of the four identified sections. The simulation results are actually recorded as generic look-up tables that can be used for any such section for the purpose of computing the associated benefit factor coefficients. Computational results are presented using data pertaining to a freeway section in San Antonio, Texas, as well as synthetic test cases, to demonstrate the effectiveness of the proposed approach, and to study the sensitivity of the quality of the solution to variations in the number of available readers.