A Snowplow Steering Guidance System Using Roadway Markers - Problem Formulation and Solution Concept

Acquisition and utilization of lateral guidance information is crucial for steering a vehicle. With practice, human drivers have performed this function quite successfully using visual perception and hand -eye coordination. However, this seemingly simple task becomes difficult when the visual information loses its clarity. Driving a snowplow during whiteout conditions is one such example. In order to improve the safety and efficiency of the snow removal operation, a supplemental guidance display was proposed and instrumented in a Caltrans (California Department of Transportation) snowplow. The guidance information was calculated based on the magnetic markers embedded in the roadway. Operations for the steering guidance system were successfully conducted on a 6.25 km freeway over Donner Summit on Interstate 80 in California during the 1998-1999 winter season. The key to this success was a transformation of the guidance display problem into a control problem. This paper describes the problem formulation and the solution concept for this steering guidance system.     

Snowplow Steering Guidance with Gain Stabilization

Acquisition and utilization of lateral guidance information is crucial for steering a vehicle. With practice, drivers can successfully perform the steering function using visual perception and hand-eye coordination. However, this seemingly simple task becomes difficult when the visual information loses its clarity. Driving a snowplow during whiteout conditions is one such example. In order to improve the safety and efficiency of snow removal operations, a supplemental guidance display was proposed and successfully implemented in a California Department of Transportation (Caltrans) snowplow. The guidance information was calculated based on the magnetic markers embedded in the roadway. The crucial step to this success is a transformation of the guidance display problem into a robust driver-in-the-loop control problem. This transformation considers the ‘display’ law as part of the overall driver-steering-control algorithm. Two key ‘assumptions’ for this design are (1) the ‘display’ law should be designed in such a way that drivers can use ‘proportional’ control gain alone to satisfy the performance and stability requirements of the steering tasks, and (2) the driver steering model can be described as a combination of gain and dynamic delay under the display law in (1). This paper describes the validation process for the ‘gain’ stabilization design concept as well as the associated driver steering model using the initial snowplow test data.     

Snowplow Steering Guidance with Gain Stabilization

Acquisition and utilization of lateral guidance information is crucial for steering a vehicle. With practice, drivers can successfully perform the steering function using visual perception and hand-eye coordination. However, this seemingly simple task becomes difficult when the visual information loses its clarity. Driving a snowplow during whiteout conditions is one such example. In order to improve the safety and efficiency of snow removal operations, a supplemental guidance display was proposed and successfully implemented in a California Department of Transportation (Caltrans) snowplow. The guidance information was calculated based on the magnetic markers embedded in the roadway. The crucial step to this success is a transformation of the guidance display problem into a robust driver-in-the-loop control problem. This transformation considers the 'display' law as part of the overall driver-steering-control algorithm. Two key 'assumptions' for this design are (1) the 'display' law should be designed in such a way that drivers can use 'proportional' control gain alone to satisfy the performance and stability requirements of the steering tasks, and (2) the driver steering model can be described as a combination of gain and dynamic delay under the display law in (1). This paper describes the validation process for the 'gain' stabilization design concept as well as the associated driver steering model using the initial snowplow test data.     

Closed-loop snowplow applicator control using road condition measurements

Closed-loop control of a snowplow applicator, based on direct measurement of the road surface condition, is a valuable technology for the optimisation of winter road maintenance costs and for the protection of the environment from the negative impacts of excessive usage of de-icing chemicals. To this end, a novel friction measurement wheel is designed to provide a continuous measurement of road friction coefficient, which is, in turn, utilised to control the applicator automatically on a snowplow. It is desired that the automated snowplow applicator deploy de-icing materials right from the beginning of any slippery surface detected by the friction wheel, meaning that no portion of the slippery road surface should be left untreated behind, as the snowplow travels over it at a reasonably high speed.

This paper describes the developed wheel-based measurement system, the friction estimation algorithm and the expected performance of the closed-loop applicator system. Conventional and zero velocity applicators are introduced and their hardware time delays are measured in addition to the time delay of the friction estimation algorithm. The overall performance of the closed-loop applicator control system is shown to be reliable at typical snowplowing speeds if the zero velocity applicator is used.     

某中型4×2载货车方向盘自动偏转问题的分析与改进

针对某中型4×2载货车空车到装满货物后方向盘自动偏转的问题,文章从转向传动系统与前悬架系统运动协调性的角度进行分析,分别借助作图法和ADAMS软件对转向传动系统与前悬架系统之间运动干涉量进行计算分析,并提出具体的优化改进措施,解决整车加载过程中方向盘偏转的问题。     

复杂路况下汽车主动避撞报警技术研究

汽车主动避撞报警技术对提高行车安全有重要意义,但如何减少复杂路况下行车时的误警率是当前需解决的关键问题。通过测量车载信息如汽车转向角度、车速、制动信号、转向灯信号等获知汽车的行驶状态,利用雷达技术感知路况和危险,基于合理的报警算法和控制策略,研制出复杂路况下的汽车主动避撞报警系统。通过实际道路报警试验,结果表明所采取的减少误警率的方法是有效的,所开发的报警系统更趋实用化。     

Flow-field guided steering control for rigid autonomous ground vehicles in low-speed manoeuvring

ABSTRACT

This paper studies the low-speed manoeuvring problem for autono-mous ground vehicles operating in complex static environments. Making use of the intrinsic property of a fluid to naturally find its way to an outflow destination, a novel guidance method is proposed. In this approach, a reference flow field is calculated numerically through Computational Fluid Dynamics, based on which both the reference path topology and the steering reference to achieve the path are derived in a single process. Steering control considers three constraints: obstacle and boundary avoidance, rigidity of the vehicle, plus the non-holonomic velocity constraints due to the steering system. The influences of the parameters used during the flow field simulation and the control algorithm are discussed through numerical cases. A divergency field is defined to evaluate the quality of the flow field in guiding the vehicle. This is used to identify any problematic branching features of the flow, and control is adapted in the neighbourhood of such branching features to resolve possible ambiguities in the control reference. Results demonstrate the effectiveness of the method in finding smooth and feasible motion paths, even in complex environments.     

某轻型客车转向系统设计校核

转向系统的作用是接受驾驶员的方向操作,带动连杆动作,使轮胎产生转向角来实现行驶车辆的转向.对转向系统的要求是:操纵轻便,安全可靠,有自动回正作用,传到转向盘上逆向力冲击要小.文章详细的阐述了液压转向助力系统的构成及功能,并对某轻型客车转向系统各性能参数进行设计校核,以判定转向系统的零部件参数是否满足法规及使用要求,最终...     

基于粘结-滑移理论的钢结构转向体系受力特性研究

为解决钢结构转向体系设计中锚栓受力不明确的问题,采用Abaqus/CAE三维建模软件分别对块式和横隔板式2种钢结构类型的体外预应力束转向体系建立了2种转向体系的有限元模型,并为了精确模拟锚栓的粘结-滑移特性,对锚栓节点采用了非线性弹簧本构,基于有限元计算结果分析了2种转向器受力及变形特性。结果表明:1)块式转向体系结构刚度一般,在转向力作用下锚栓受力较大,结构安全系数较低;2)横隔板式转向体系结构刚度较大,在转向力作用下,结构破坏形态是钢结构屈曲,锚栓受力较小,整个结构安全系数极高。     

SUV转向系统模态试验及优化

针对某SUV车转向系统方向盘怠速抖振过大的现象,采用模态试验技术得到转向系统的固有频率,找到产生这种现象的原因在于转向系统的固有频率和发动机怠速时的振动激励频率接近,从而引起了方向盘的过大振动。文章采用增大转向管柱的支架和车身连接处的接触面面积的方法进行结构优化,并对优化后的转向系统进行模态试验,再将优化前后方向盘的振动数据进行对比,发现优化后的转向系统振动明显改善,达到了减振的目的。     

基于模态分析的汽车转向盘怠速抖动优化

针对某轿车怠速开空调转向盘抖动的问题,对转向盘和排气系统模态进行分析,发现该车转向盘和排气系统在约束条件下的模态参数与发动机的2阶点火频率相一致.调整了其转向盘和排气系统的模态,并针对优化后转向盘进行了振动试验.结果表明,转向盘X方向的振动由0.90 m/s2降为0.31 m/s2,Y方向的振动由1.05 m/s2降为...     

Measurement and mathematical model of a driver's intermittent compensatory steering control

The compensatory (feedback) component of a human driver's steering control is examined. In particular, the effect of the cognitive process is studied. Model predictive control theory is used to implement models of intermittency in cognitive processing. Experiments using a fixed-base driving simulator with periodic occlusion of the visual display are used to reveal the nature of the driver's steering behaviour. An intermittent serial-ballistic control strategy is found to match the measured behaviour better than intermittent zero-order hold or continuous control. The findings may enable some insight to driver-vehicle interaction and vehicle handling qualities.     

An Advanced Steering System with Active Kinesthetic Feedback for Handling Qualities Improvement

Advanced Steering System with artificial steering wheel torque-active kinesthetic information feedback for improving handling qualities is discussed. Fundamentally the structure of the system may be considered to another form of model following control. In this system, a driver always remains in the control loop and receives steering control information which give him/her a direct hint to steer a steering wheel. This system works as a stability and control augmentation system of the vehicle to improve the vehicle handling qualities both in compensatory and pursuit control task, and is expected to reduce driver's workload. Effects of this system are analyzed in terms of man-machine system characteristics. Identification of driver dynamics was carried out to find why such improvement could be achieved. Availability of the proposed system is verified by analysis, simulator and proving ground tests.     

Combined longitudinal and lateral control for automated vehicle guidance

This paper deals with the longitudinal and lateral control of an automotive vehicle within the framework of fully automated guidance. The automotive vehicle is a complex system characterised by highly nonlinear longitudinal and lateral coupled dynamics. Consequently, automated guidance must be simultaneously performed with longitudinal and lateral control. This work presents an automated steering strategy based on nonlinear model predictive control. A nonlinear longitudinal control strategy considering powertrain dynamics is also proposed to cope with the longitudinal speed tracking problem. Finally, a simultaneous longitudinal and lateral control strategy helps to improve the combined control performance. This whole control strategy is tested through simulations showing the effectiveness of the present approach.     

关于车辆方向盘摆振的补偿方法及补偿系统研究

研究电动助力转向系统对方向盘摆振补偿的功能,通过对影响方向盘摆振因素的分解,当整车基本参数确定的情况下可以采用EPS进行摆振补偿.通过摆振补偿功能开发到某车型实车测试验证,有效解决高速制动等工况下方向盘摆振问题.该研究为车辆方向盘摆振问题的解决提供采用EPS补偿万式提供方法及系统.     

An Advanced Steering System with Active Kinesthetic Feedback for Handling Qualities Improvement

SUMMARY

Advanced Steering System with artificial steering wheel torque-active kinesthetic information feedback for improving handling qualities is discussed. Fundamentally the structure of the system may be considered to another form of model following control. In this system, a driver always remains in the control loop and receives steering control information which give him/her a direct hint to steer a steering wheel. This system works as a stability and control augmentation system of the vehicle to improve the vehicle handling qualities both in compensatory and pursuit control task, and is expected to reduce driver's workload. Effects of this system are analyzed in terms of man-machine system characteristics. Identification of driver dynamics was carried out to find why such improvement could be achieved. Availability of the proposed system is verified by analysis, simulator and proving ground tests.     

汽车高速方向盘摆振问题整改

解决摆振问题可提高驾驶的安全性和舒适性,文章探讨了某车型在高速时方向盘发生摆振问题的解决办法,通过改变相关件振动频率及阻尼特性来验证摆振问题。最后通过调整下摆臂衬套和转向系统相关零部件参数解决了此车的高速摆振问题,结果表明摆振的原因为系统共振所引起,通过吸收及改善此车况下的系统振动便可解决此类共振问题。     

城市中心区停车诱导系统规划设计研究——以虹口区四川北路商业区为例

该文以上海市四川北路商业区停车诱导系统规划设计为例,结合四川北路商业区的交通特征和停车问题,以及国内外停车诱导系统的规划设计经验,提出停车诱导系统规划设计的总体理念和原则。然后,就停车诱导系统规划设计时遇到停车诱导系统架构、停车信息发布屏的版面设计、停车泊位采集装置的选用和信息传输方式等问题进行了探讨,为停车诱导系统的规划设计提供了一个良好的借鉴与思路。     

Stabilization of Passenger Car-Caravan Combination Using Four Wheel Steering Control

This study aims to stabilize the trailer at high speed. The behavior of passenger cars with four wheel steering system, vehicles with rear wheel steering and of trailer and passenger car are similar. This is regarded as an optimal regulator problem with linear equation of motion, and a state variables feedback control system is adopted. The problem of stability at high speed on a straight course can be solved. Therefore, the passenger car-trailer system can be stabilized. Furthermore, this study indicates the way forward to stabilize a passenger car-trailer system.     

停车诱导信息板泊位状况显示优化模型

在考虑停车诱导率的基础上,综合考虑停车诱导信息板在路网中所处位置、道路交通状况和停车泊位的变化趋势等影响因素,以进入诱导区域内所有停放车辆到达停车场的车公里数(vehicle kilometers of travel,VKT)最小为目标,建立了停车诱导信息板泊位状况显示优化模型。该模型可以确定某一显示时间间隔内,诱导区域内所有停车诱导信息板泊位状况显示结果的最优组合。算例分析表明,该模型是可行的,且随着停车诱导率的增加,VKT随之下降,诱导效果随之提高。