Crosswind Feedforward Control – A Measure to Improve Vehicle Crosswind Behaviour

SUMMARY

The theory of crosswind feedforward control was explained using the example of a vehicle with active front-wheel steering. Beforehand, the calculation formulas and frequency responses of the transient crosswind force and of the wind yaw moment acting on the vehicle were derived using the example of a simple vehicle fluid model. The influence of the transiency of crosswind disturbance on the dynamic crosswind behaviour of a vehicle was then presented. The results of simulation confirmed the analyses carried out in the frequency domain for feedforward control with front, rear and all-wheel steering. With front-wheel steering, the influence of crosswind on one of the vehicle movement variables (lateral acceleration or yaw rate) could be almost completely compensated by dynamic feedforward control. With rear-wheel steering, it is only possible to compensate directly for the influence on the yawing rate. Due to the setting of the side force in the same direction as the lateral wind force at the start, active rear-wheel steering is not so successful as active front-wheel steering. Nevertheless, the crosswind behaviour of a vehicle can be considerably enhanced by feedforward control with rear-wheel steering. The best crosswind behaviour was obtained with active all-wheel steering: the vehicle hardly responds at all to crosswinds and remains on course despite heavy gusts of wind.     

Active Suspension Control to Improve Vehicle Ride and Handling

In practice most active vehicle suspension work can be traced to two sources, Lotus' modal control and Karnopp's skyhook damper. A model is developed which allows comparison of different active suspension control algorithms. The Lotus modal control algorithm is reviewed, and compared with Karnopp's skyhook damper. It is shown that a tight inner closed loop allows the Lotus algorithm to achieve the inertial damping described by Kamopp for a single comer or quarter car. It is suggested that to achieve simultaneously high inertial damping and good disturbance rejection an inner force loop is desirable. A vehicle control scheme is presented which combines the Lotus modal decomposition with Karnopp's skyhook damper, allowing nearly optimal ride and simultaneously permitting modification of vehicle handling properties.     

基于滑模理论的高速车辆侧风稳定性控制研究

针对高速车辆侧风稳定性问题,搭建了汽车多体动力学(multi-body dynamics,MBD)和计算流体力学(computational fluid dynamics,CFD)双向耦合平台,并基于该平台设计了一种侧风稳定性控制系统.该系统的上层控制器基于滑模理论计算出侧风干扰下的高速车辆为维持稳定所需的附加横摆力矩...     

应用汽车行驶记录仪提高行车安全性

汽车违章超速行驶造成的责任事故越来越多,汽车运输企业为行车安全花费的资源不少,但效果不大。利用汽车行驶记录仪———俗称汽车黑匣子,加强对车辆的动态监控,有效地控制车辆的超速超时现象,遏止行车事故的形成,起到了良好的管理效果。介绍汽车行驶记录仪的基本功能、安装及使用。     

电控硅油风扇改善车辆燃油经济性的试验研究

本文介绍了电控硅油风扇改善车辆燃油经济性的试验研究过程。研究结果表明:电控硅油风扇匹配在某8.9 L电控柴油机上比温控硅油风扇的车辆等速油耗节省4-5%,车辆平原高速油耗节省3%。     

提高智能化测量与控制仪器抗干扰性能的软件措施

目前智能化测量与控制仪器在工程技术中得到了广泛地使用,然而很多智能化测量与控制仪器忽视了软件抗干扰技术,使得系统的可靠性下降.本文对主要的软件抗干扰技术进行了探讨.     

Application of Aerodynamic Actuators to Improve Vehicle Handling

This exploratory study considers applications of active aerodynamic devices for suppressing parasitic motion and for improving the response of vehicles to steering, within the scope of the linear dynamic behaviour. A three DOF linear model is chosen to describe the side slip, yaw and roll motion of a baseline front-wheel steered vehicle. The improvements in performance of the base-line vehicle that are achievable by the application of direct yaw and roll moments are determined when either an open loop control pre-filter or a state feedback control law based on LQR design is applied. Unlike the former control, the state feedback control is unable to make the body side-slip angle vanish. The feedback control performance of each of the two moment actuators has been examined separately and then jointly. The advantages of combining the open loop and feedback dual actuator configurations are demonstrated using the two-degree of freedom control scheme. It is found that the scheme yields a spectacular performance but demands unreasonably large moments from the actuators in the context of available aerodynamic forces. On the other hand, the demand on direct yaw and roll moment of actuators is modest when the actuators are controlled using the LQR feedback only and if the control design is used to track a desired yaw rate trajectory and simultaneously to reduce the parasitic rolling motion. Significant improvements in handling and dynamic stability of a base-line vehicle can be achieved by aerodynamically generated direct yaw and roll actuator moments provided the target control performance is reasonable. The configurations of aerodynamic actuators considered are feasible for improving vehicle handling in cornering on motorways but more work remains to be done to explore alternative aerodynamic configurations that give rise to less side effects and higher lift coefficients.     

Application of Aerodynamic Actuators to Improve Vehicle Handling

This exploratory study considers applications of active aerodynamic devices for suppressing parasitic motion and for improving the response of vehicles to steering, within the scope of the linear dynamic behaviour. A three DOF linear model is chosen to describe the side slip, yaw and roll motion of a baseline front-wheel steered vehicle. The improvements in performance of the base-line vehicle that are achievable by the application of direct yaw and roll moments are determined when either an open loop control pre-filter or a state feedback control law based on LQR design is applied. Unlike the former control, the state feedback control is unable to make the body side-slip angle vanish. The feedback control performance of each of the two moment actuators has been examined separately and then jointly. The advantages of combining the open loop and feedback dual actuator configurations are demonstrated using the two-degree of freedom control scheme. It is found that the scheme yields a spectacular performance but demands unreasonably large moments from the actuators in the context of available aerodynamic forces. On the other hand, the demand on direct yaw and roll moment of actuators is modest when the actuators are controlled using the LQR feedback only and if the control design is used to track a desired yaw rate trajectory and simultaneously to reduce the parasitic rolling motion. Significant improvements in handling and dynamic stability of a base-line vehicle can be achieved by aerodynamically generated direct yaw and roll actuator moments provided the target control performance is reasonable. The configurations of aerodynamic actuators considered are feasible for improving vehicle handling in cornering on motorways but more work remains to be done to explore alternative aerodynamic configurations that give rise to less side effects and higher lift coefficients.     

商品汽车运输: 我们还需要改变什么? ——车辆运输车结构在商用车运输领域尚有潜力可挖

随着国民经济的快速增长和人民消费水平的稳步提高,近些年我国汽车的需求量、保有量、产销量以及出口量均保持了快速增长势头.     

用非实时自动车辆定位系统来改善公交车的服务

阐明当采取公交优先措施后，用非实时AVL(自动车辆定位)系统如何识别最好收益路线，并通过分析实际情况与行驶计划的差异及其发生原因，对行车计划进行优化。提出一种基于非实时AVL数据和乘客数量来计算车辆沿线乘客到达率的新方法，并以此来估计车站每年的客流量以及公交车在车站间的行驶速度。     

A Variable Free Control Characteristic Vehicle

A variable characteristic car (VCC) has been developed at Melbourne University for driverlvehicle handling research. The vehicle is unusual in that it has facilities for varying both its fixed control and free control dynamic characteristics over wide ranges. In this paper the servo systems used to effect these changes are described. The calibration methods used to relate the vehicle response characteristics to the variable servo settings are detailed. Sample calibration results are given for the fixed control parameters steering ratio, yaw response time and stability factor. Calibration of the free control parameters is also described and results are given for the steering torque gradient, and the time-to-peak and percentage overshoot of the steering wheel motion in response to a step input of torque.     

一种基于汽车动力截止控制超载的技术模型

提出一个从汽车控制技术的角度治理汽车超载的技术模型,其中包括汽车超载测定与判别、防止动载荷干扰、汽车动力截止以及防止相关装置被人为拆除的反向控制技术等。模型根据轴荷判断汽车是否超载,通过动力截止使得超载汽车不能运行,从而达到防止汽车超载的目的。     

提高车辆动态称重仪精度的研究与试验

以提高车辆动态称重精度为目的，从两方面提出了改善措施：在分析车辆通过秤台时受力情况的基础上，设计了一种高精度的称重传感器；针对动态称重实际波形，设计了一种新的数据处理方法。通过对硬件和软件的改善，提高了动态称重精度。     

提高某越野运兵车乘坐舒适性的悬架设计

文章针对某越野运兵车,通过对悬架系统的结构和零部件进行改进设计,来提高运兵车的乘坐舒适性。     

路域内双条杉天牛的综合控制

双条杉天牛是危害桧柏类树木的重要害虫，对用做中央隔离带和其它用作景观美化的桧柏造成极大危害。本文以它为例阐述在公路领域的病虫害防治手段和原理。