考虑路面不平度神经网络的悬架参数优化

以1/4车辆模型为例,构建了考虑路面不平度的3×3神经网络系统,并进行了多种路面条件下汽车悬架参数优化。计算结果表明,将路面不平度作为神经网络输入之一的神经网络优化系统与已有神经网络系统相比,可使设计人员综合考虑路面的影响,从而得到适应条件更广泛的悬架参数。     

Heavy-duty vehicle modelling and longitudinal control

This paper addresses modelling, longitudinal control design and implementation for heavy-duty vehicles (HDVs). The challenging problems here are: (a) an HDV is mass dominant with low power to mass ratio; (b) They possess large actuator delay and actuator saturation. To reduce model mismatch, it is necessary to obtain a nonlinear model which is as simple as the control design method can handle and as complicated as necessary to capture the intrinsic vehicle dynamics. A second order nonlinear vehicle body dynamical model is adopted, which is feedback linearizable. Beside the vehicle dynamics, other main dynamical components along the power-train and drive-train are also modelled, which include turbocharged diesel engine, torque converter, transmission, transmission retarder, pneumatic brake and tyre. The braking system is the most challenging part for control design, which contains three parts: Jake (engine compression) brake, air brake and transmission retarder. The modelling for each is provided. The use of engine braking effect is new complementary to Jake (compression) brake for longitudinal control, which is united with Jake brake in modelling. The control structure can be divided into upper level and lower level. Upper level control uses sliding mode control to generate the desired torque from the desired vehicle acceleration. Lower level control is divided into two branches: (a) engine control: from positive desired torque to desired fuel rate (engine control) using a static engine mapping which basically captures the intrinsic dynamic performance of the turbo-charged diesel engine; (b) brake control: from desired negative torque to generate Jake brake cylinder number to be activated and ON/OFF time periods, applied pneumatic brake pressure and applied voltage of transmission retarder. Test results are also reported.     

城市交通控制系统信号控制单元集成化研究

在分析当前城市交通信号控制系统发展趋势的基础上,针对我国城市交通实际应用中存在的各类信号控制单元自成体系难以统一的问题,提出了一个实用的信号控制单元集成的解决方案,首先介绍集成化城市交通控制系统,然后介绍信号控制单元集成化方案的功能框架和技术实施方法,从而实现了一个控制系统软件可以兼容多种不同型号信号机的目标,并且在实际系统开发中获得了应用。     

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介绍了基于GPRS的自动车辆定位系统的数据链路，并结合GPRS数据用户的工作流程，介绍了实现链路的关键技术。从语音传输和数据传输两个方面给出了基于GPRS数据链路的自动车辆定位系统（AVLS）系统模型。着重对数据接入延时与语音负载、数据长度、数据发送间隔、系统容量等参数之间的关系进行了仿真分析。仿真结果表明,对于语音负载小、数据长度小的自动车辆定位系统，GPRS可以用来实现系统的大容量。     

基于BP人工神经网络的城市轨道交通线网规划的综合评价

城市轨道交通线网规划传统的评价方法主要有层次分析法和模糊综合评判法等,而这些评价方法因其不可避免的主观性而导致评价结果可靠性不高.本文采用BP人工神经网络模型对城市轨道交通线网的规划方案进行评价,有效避免了评价过程中人工过多参与造成的主观性偏差,并采用仿真软件验证其有效性和可行性.     

桥面连续受力分析

对桥面连续在温度和荷载作用下的受力情况进行了分析,将要在今后设计工作中加以改进并在材料上和施工中加以完善。     

汽车用表面处理钢板的发展(Ⅰ)

工业化进程带来的大气腐蚀以及道路防冻盐和海洋气氛对汽车车身的腐蚀，迫使世界各国的汽车生产厂家越来越多地使用表面处理钢板。针对汽车生产需求的变化，近十年来，世界各国在表面处理钢板的生产工艺和技术方面进行了许多重大改进，研制、开发了一批新型的汽车用表面处理钢板。本文综述了近年来世界主要工业化国家以及我国汽车用表面处理钢板的进展。     

Fuzzy-logic applied to yaw moment control for vehicle stability

In this paper, we propose a new yaw moment control based on fuzzy logic to improve vehicle handling and stability. The advantages of fuzzy methods are their simplicity and their good performance in controlling non-linear systems. The developed controller generates the suitable yaw moment which is obtained from the difference of the brake forces between the front wheels so that the vehicle follows the target values of the yaw rate and the sideslip angle. The simulation results show the effectiveness of the proposed control method when the vehicle is subjected to different cornering steering manoeuvres such as change line and J-turn under different driving conditions (dry road and snow-covered).     

Nonlinear PI front and rear steering control in four wheel steering vehicles

Vehicle steering dynamics show resonances, which depend on the longitudinal speed, unstable equilibrium points and limited stability regions depending on the constant steering wheel angle, longitudinal speed and car parameters.

The main contribution of this paper is to show that a combined decentralized proportional active front steering control and proportional-integral active rear steering control from the yaw rate tracking error can assign the eigenvalues of the linearised single track steering dynamics, without lateral speed measurements, using a standard single track car model with nonlinear tire characteristics and a non-linear first-order reference model for the yaw rate dynamics driven by the driver steering wheel input. By choosing a suitable nonlinear reference model it is shown that the responses to driver step inputs tend to zero (or reduced) lateral speed for any value of longitudinal speed: in this case the resulting controlled vehicle static gain from driver input to yaw rate differs from the uncontrolled one at higher speed. The closed loop system shows the advantages of both active front and rear steering control: higher controllability, enlarged bandwidth for the yaw rate dynamics, suppressed resonances, new stable cornering manoeuvres, enlarged stability regions, reduced lateral speed and improved manoeuvrability; in addition comfort is improved since the phase lag between lateral acceleration and yaw rate is reduced.

For the designed control law a robustness analysis is presented with respect to system failures, driver step inputs and critical car parameters such as mass, moment of inertia and front and rear cornering stiffness coefficients. Several simulations are carried out on a higher order experimentally validated nonlinear dynamical model to confirm the analysis and to explore the robustness with respect to unmodelled dynamics.