The Static Stability of Articulated Commercial Vehicles

SUMMARY

This review of the state of the art emphasizes recent results that have been obtained in extending conventionalanalysis techniques to the treatment of “Highway Trains”, that is, to heavy trucks that have multiple articulation points and employ suspensions with multiple axles. Equations of motion applicable to the equilibrium turning performances of articulated vehicles are examined with respect to using analysis techniques involving steering gains, understeer gradients, effective wheel-bases, handling diagrams, and critical speeds. These examinations provide the basis for in sights into simplified approaches for understanding the steady turning mechanics of articulated, multi-axle vehicles riding on pneumatic tires.     

Stability Criteria for Articulated Railway Vehicles Possessing Perfect Steering

SUMMARY

The general form of the equations o f motion o f multi-body articulated railway vehicles are used to establish the conditions which the elastic stiffness matrix, which describes the nature and configuration o f the suspension elements connecting the various bodies, must satisfy in order to achieve both perfect steering on circular curves and dynamic stability. The resulting criteria are then used to discuss the properties of various multi-axle configurations which are either typical of current practice or possibilities for future designs.     

Stability Criteria for Articulated Railway Vehicles Possessing Perfect Steering

The general form of the equations o f motion o f multi-body articulated railway vehicles are used to establish the conditions which the elastic stiffness matrix, which describes the nature and configuration o f the suspension elements connecting the various bodies, must satisfy in order to achieve both perfect steering on circular curves and dynamic stability. The resulting criteria are then used to discuss the properties of various multi-axle configurations which are either typical of current practice or possibilities for future designs.     

Active Roll Control of Articulated Vehicles

This paper describes an investigation into active roll control of articulated vehicles. The objective is to minimise lateral load transfer using anti-roll bars incorporating low bandwidth hydraulic actuators. Results from handling tests performed on an articulated vehicle are used to validate a nonlinear yaw/roll model of the vehicle. The methodology used to design lateral acceleration controllers for vehicles equipped with active anti-roll bars is developed using a simplified linear articulated vehicle model. The hardware limitations and power consumption requirements of the active elements are studied. The controller is then implemented in the validated articulated vehicle model to evaluate the performance of an articulated lorry with active anti-roll bars. The simulation results demonstrate the possibility of a significant improvement in transient roll performance of the vehicle, using a relatively low power system (10 kW), with low bandwidth actuators (5 Hz).     

车辆稳定性控制在奔驰商用车中的应用

目前,主动安全技术作为汽车安全的重要手段之一,已经得到汽车制造厂商的普遍重视。与此同时,车辆局域网的普遍采用,使得早期相对独立的各种功能,通过计算机网络重新组合起来,相互协同,组成一个新的更强的系统。其中的车辆稳定控制系统就是这一组合系统的典型范例。它将发动机的     

商用车市场调整过后展新局——中国商用车市场2006年回眸与2007年展望

回眸2006年,“十一五”开局之年,中国汽车市场的表现的确不同凡响,车市实际增长明显高于预期,商用车市场缓步走出调整期。展望2007年,党的十七大即将召开,宏观经济更加稳健,中国车市前景看好,但商家鏖战亦急,市场博弈也愈难。2006年车市:果然就旺了起来2006年是中国旧历的狗年,     

Static and Dynamic Stability of Unsymmetric Two-Axle Railway Vehicles Possessing Perfect Steering

For railway vehicles having coned wheels mounted on solid axles, there is a conflict between the stability of lateral deviations from the motion along the track and the ability to steer round curves. A general theory is developed for the two-axle vehicle in which there is a lack of symmetry, fore-and-aft, both of the interwheelset structure and of the equivalent conicities of the wheelsets. It is shown that whilst parameters can be selected which provide static and dynamic stability and perfect steering for both directions of motion, there is a lightly damped mode of oscillation for any practical configuration and the significance of this is discussed.     

商用车资讯

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Static and Dynamic Stability of a Class of Three-Axle Railway Vehicles Possessing Perfect Steering

For railway vehicles having coned wheels mounted on solid axles there is, in general, a conflict between stability of lateral deviations from the motion along the track and ability to steer round curves. However, the three-axle vehicle with zero bending stiffness and with shear elasticity between all wheelsets can satisfy the requirement of perfect steering and for a range of values of equivalent conicity possesses both static and dynamic stability. The static and dynamic stability of the most general form of symmetric three-axle vehicle is investigated, and stability criteria derived.     

Roll Plane Analysis of Articulated Tank Vehicles During Steady Turning

SUMMARY

The rollover immunity levels of articulated tank vehicles with partial loads are investigated. A static roll plane model of the articulated vehicle employing partially filled cylindrical tank is developed. The vertical and lateral translation of the liquid cargo due to vehicle roll angle and lateral acceleration, encountered during steady turning, are evaluated. The roll moments arising from vertical and lateral translation of the liquid cargo are determined and incorporated in the roll plane model of the vehicle. The adverse influence of the unique interactions of the liquid within the tank vehicle, on the rollover limit of the articulated vehicle is demonstrated. The influence of compartmenting of the tank on the steady turning roll response of the vehicle is analyzed, and an optimal order of unloading the compartmented tank is discussed.     

Roll Plane Analysis of Articulated Tank Vehicles During Steady Turning

The rollover immunity levels of articulated tank vehicles with partial loads are investigated. A static roll plane model of the articulated vehicle employing partially filled cylindrical tank is developed. The vertical and lateral translation of the liquid cargo due to vehicle roll angle and lateral acceleration, encountered during steady turning, are evaluated. The roll moments arising from vertical and lateral translation of the liquid cargo are determined and incorporated in the roll plane model of the vehicle. The adverse influence of the unique interactions of the liquid within the tank vehicle, on the rollover limit of the articulated vehicle is demonstrated. The influence of compartmenting of the tank on the steady turning roll response of the vehicle is analyzed, and an optimal order of unloading the compartmented tank is discussed.     

Roll Dynamics of Commercial Vehicles

An analytical model is developed here for studying the roll dynamics of commercial vehicles. Large displacements and rotations are accounted for in this nonlinear model so that it can be used for the study of roll dynamics well beyond the limits of wheel lift-off. The model is used to illustrate some of the dynamic phenomena in vehicle rollover, especially the interactive coupling between the roll and the vertical modes of motion. The influence of suspension backlash on rollover resistance is demonstrated, and the phenomenon of roll motion resonance is illustrated to suggest new means for evaluating vehicle rollover sensitivity.     

Theoretical Analysis of the Steering Behaviour of Articulated Frame Steer Vehicles

A theoretical analysis of the steering behaviour of articulated frame steer vehicles is presented. It includes details of the hydraulic steering system as well as the equations governing motion of the front and rear body units. Both oscillatory and exponential instabilities can occur with this type of vehicle. The most sensitive design feature is the steering system, which governs the effective torsional stiffness around the pivot. Other important features which influence stability are speed and centre of gravity positions of the bodies.     

7月,商用汽车历史性发展机遇呈现

2001年7月,一个不平凡的月份:从月初纪念中国共产党成立80周年,紧接着国家经贸委向社会公布了包括汽车、机械、冶金等1 3个行业的"十五"规划;7月4日又传来了中国加入WTO实质性谈判已经完成的消息;而7月1 3日晚北京赢得了2008年奥运会的主办权,又将中国与世界之间的距离拉近.在冷静思考之后,笔者深切地感受到我国商用汽车行业发展的历史性机遇已经呈现,相信借着良好的政策导向和社会需求拉动,我国的商用汽车在最近的几年中将会有突飞猛进的发展.     

针对铰接工程车辆的变角度全景环视系统研究

针对铰接工程车辆车头与车厢间存在铰接角度且车身长导致的视觉盲区大的问题,提出了一种可以根据铰接角度实时调整拼接图像的变角度全景环视系统。对于静态俯视图像的生成,提出一种用于将畸变图像转换为俯视图像并对齐到指定位置的查找表快速映射方法,实现了通过一步变换完成鱼眼校正、逆透视变换与图像配准,提升了静态俯视图像生成的速率。对于动态全景环视图像的生成,提出了一种根据铰接角度改变后对应的动态查找表直接生成变角度全景环视图像的方法,提升了角度改变时图像重新配准的速率。对于全景环视图像的融合,提出了一种循环颜色调整和透明度融合相结合的方法,从而对整幅变角度全景环视图像进行均衡化处理并降低拼接缝带来的图像损失。试验结果表明：在同样的硬件平台下,对于静态俯视图像的生成,该系统不仅将运行速度提升了接近1倍,并且有效减少了图像的失真程度;在图像融合方面,该系统不仅获得了较好的融合效果,并且保证了运行的实时性;通过实车验证,该系统可以生成全局均衡且无缝的变角度全景环视图像并在嵌入式处理器上实现了接近30 帧·s^-1的处理速度;该系统实时生成的变角度全景环视图像可以有效消除铰接工程车辆周围的视觉盲区,从而提升铰接工程车辆行驶的安全性和便捷性。