Some Design Aspects of Anti-Lock Brake Systems for Commercial Vehicles

In this paper a simulation model of tractor-semitrailers suitable for design and performance analysis of anti-lock systems is presented. The model is used to evaluate the effects of various methods of prediction and reselection of the anti-lock system on the braking performance of tractor-semitrailers. The characteristics and the equivalent control logic of a commercially available anti-lock system are examined and its deficiencies are identified. To rectify these deficiencies, improved methods of prediction and reselection are proposed. A comparison of the slip characteristics and braking effectiveness between the proposed and the commercially available systems is made. The effects of various types of control logic on the steerability and directional stability of tractor-semitrailers and on the air consumption of the brake systems will be examined in a separate paper.     

Some Design Aspects of Anti-Lock Brake Systems for Commercial Vehicles

SUMMARY

In this paper a simulation model of tractor-semitrailers suitable for design and performance analysis of anti-lock systems is presented. The model is used to evaluate the effects of various methods of prediction and reselection of the anti-lock system on the braking performance of tractor-semitrailers. The characteristics and the equivalent control logic of a commercially available anti-lock system are examined and its deficiencies are identified. To rectify these deficiencies, improved methods of prediction and reselection are proposed. A comparison of the slip characteristics and braking effectiveness between the proposed and the commercially available systems is made. The effects of various types of control logic on the steerability and directional stability of tractor-semitrailers and on the air consumption of the brake systems will be examined in a separate paper.     

汽车后轴侧滑动态特性及稳定性研究

本文建立了汽车在制动时后轮抱死侧滑的力学模型，分析了汽车后轴侧滑的运动规律及其动态特性，结合汽车前后累的制动比例关系，通过计算机求解出了在汽车紧急制动时保证侧滑相对稳定的参数允许变化区域，为提高汽车的制动稳定性提供了一种有效的计算和分析方法。     

Dynamic Behaviour of a Mobile Robot Vehicle with a Two Caster and Two Driving Wheel Configuration

The actual trajectory covered by a mobile robot in motion differs from the trajectory planned on the basis of the kinematic characteristics of its directional control system. This difference is essentially related to the behaviour of wheel-road contact, the influence of dynamic loads and the presence of caster wheels.

This paper presents a mathematical model (“ DDPP) which simulates the motion of a generic mobile robot vehicle with a propulsion and directional control system based on two independent driving wheels and two caster wheels.

The differential equations of motion have been obtained by applying modified equations of Lagrange.

The role played by the dynamic loads, the wheel-road contact features and the caster wheels is discussed hereof.     

汽车制动过程的计算机模拟分析

通过建立汽车制动过程的数字模型，用计算机模拟分析了汽车的制动响应及各种敏感因素对它的影响，同时，进一步分析了引起汽后前后轮先后抱死拖滑的主要原因和影响程度，为汽车制动和制动稳定性的研究提供了参考。     

轿车轴间制动力分配要求的试验研究

本文在切诺基吉普车实车试验的基础上，结合其它轿车的试验结果，对制动标准中有关轿车轴间制动力分配的要求进行了研究。结果表明，为获得良好的制动稳定性，较高的制动效能，增加前轴制动力，减少后轴制动力是现代轿车轴间制动分配设计的发展趋势；要求过大的后轴制动力，在常遇路面上强力制动，将会导致后轮首先抱死，与ＥＣＥＲ１３要求不相符。     

基于Simulink/Cruise的6AT液力变矩器闭锁性能联合仿真

根据液力变矩器的工作原理及闭锁条件,制定液力变矩器控制策略。利用Simulink建立液力变矩器控制模型,并利用Cruise和Simulink进行联合仿真,验证控制策略的可行性。仿真结果表明,液力变矩器控制模型正确,闭锁离合器能够准确按照闭锁条件闭锁,并且可以显著改善车辆的燃油经济性和排放性能。本文的研究可以为液力变矩器的闭锁研究提供一定的理论依据。     

Application of the Pacejka Magic Formula Tyre Model on a Study of a Hydraulic Anti-Lock Braking System for a Light Motorcycle

The object of the study is to apply the Pacejka magic formula tyre model on a study of a hydraulic anti-lock braking system, especially applied to a light motorcycle. A sliding mode PWM controller is designed and tested. Both simulation and experimental studies of an anti-lock braking system are undertaken. The paper presents an analytical approach for estimating the longitudinal adhesive coefficient between a tyre and the road through the magic formula tyre model, the parameters of which are identified by a genetic algorithm. A dynamic analysis of a light motorcycle is carried out in detail. The experimental results show that the antilock braking system designed in the study is effective to prevent wheels locking during emergency braking. The proposed simulation results match experimental data well.     

Application of the Pacejka Magic Formula Tyre Model on a Study of a Hydraulic Anti-Lock Braking System for a Light Motorcycle

The object of the study is to apply the Pacejka magic formula tyre model on a study of a hydraulic anti-lock braking system, especially applied to a light motorcycle. A sliding mode PWM controller is designed and tested. Both simulation and experimental studies of an anti-lock braking system are undertaken. The paper presents an analytical approach for estimating the longitudinal adhesive coefficient between a tyre and the road through the magic formula tyre model, the parameters of which are identified by a genetic algorithm. A dynamic analysis of a light motorcycle is carried out in detail. The experimental results show that the antilock braking system designed in the study is effective to prevent wheels locking during emergency braking. The proposed simulation results match experimental data well.     

基于自适应卡尔曼算法的重型半挂车状态估计研究

在建立三轴重型半挂车简化动力学模型的基础上,提出了用于估计重型半挂车运动状态的自适应卡尔曼滤波估计算法。利用动力学软件Trucksim对该估计算法进行了验证,验证结果表明,所提出的自适应卡尔曼滤波算法能够在车速为30 km/h与60 km/h的两种扫频工况下,准确估计重型半挂车横摆角速度和铰接角,为重型半挂车的稳定性控制奠定了基础。     

New Control Technique for Maximizing Braking Force on Antilock Braking System

In this paper, we propose a new control strategy for an antilock braking system (ABS) to maintain the braking force at maximum. The popularization of the ABS that prevents the wheels from locking has resulted in an improvement of the vehicle stability and shortening of the braking distance. Further improvement is anticipated if the maximization of the braking force is realized. We found an interesting phenomenon in which the characteristics of the resonance system composed of the vehicle body and the wheel and road surface reflects the slip condition of the road surface. Using this phenomenon, we realized a control method for maintaining the maximum value of the braking force.     

New Control Technique for Maximizing Braking Force on Antilock Braking System

In this paper, we propose a new control strategy for an antilock braking system (ABS) to maintain the braking force at maximum. The popularization of the ABS that prevents the wheels from locking has resulted in an improvement of the vehicle stability and shortening of the braking distance. Further improvement is anticipated if the maximization of the braking force is realized. We found an interesting phenomenon in which the characteristics of the resonance system composed of the vehicle body and the wheel and road surface reflects the slip condition of the road surface. Using this phenomenon, we realized a control method for maintaining the maximum value of the braking force.     

轿车油箱锁紧盖失效原因分析

某汽车公司2001年底投放市场的轿车,在我国海南使用中有个别车的油箱锁紧盖回油管座根部出现裂纹,存在燃油渗漏故障。针对该车的相关零部件(油箱、油管及油箱锁紧盖)进行了测试,结合车辆具体结构和海南的使用条件,通过分析得出了油箱锁紧盖的失效原因并提出了改进方案。通过对改进后的油箱锁紧盖进行的试验测试,证明了对该油箱锁紧盖失效原因的分析是正确的,改进方案可行。     

Optimisation of handling and traction in a rear wheel drive vehicle by means of magneto-rheological semi-active differential

This paper presents a semi-active differential, magneto-rheological fluid limited slip differential, which allows us to bias the torque between the driving wheels. It is based on the magneto-rheological fluid employment, by which it is possible to change, in a controlled manner, the internal friction torque and, consequently, the torque bias ratio. This device is an adaptive one and allows us to obtain an asymmetric torque distribution in order to improve vehicle handling. The device modelling and the control algorithm, realised for this activity, are described. The illustrated results highlight the advantages that are attainable regarding directional behaviour, stability, and traction.     

Dynamic analysis and control of an anti-lock brake system for a motorcycle with a camber angle

This paper analyses the dynamic response of a motorcycle with an anti-lock brake system (ABS) and camber or steering angle. Most studies have assumed that motorcycles brake in a straight line – that is, without a steering or camber angle. In this work, the performance of an ABS modulator is designed and analysed at first. Then, a controller is designed for motorcycle turning. The controller uses angular acceleration and the pressure value in brake calipers on the front and rear wheels, camber angle and lateral acceleration as commands to control brake pressure on each wheel to prevent wheel locking. The equation of motion for a motorcycle is based on Weir's equations. This motorcycle model combines a mathematical equation of the ABS modulator, tyre model and controller in simulations.     

Total dynamic response of a PSS vehicle negotiating asymmetric road excitations

A planar suspension system (PSS) is a novel automobile suspension system in which an individual spring–damper strut is implemented in both the vertical and longitudinal directions, respectively. The wheels in a vehicle with such a suspension system can move back and forth relative to the chassis. When a PSS vehicle experiences asymmetric road excitations, the relative longitudinal motion of wheels with respect to the chassis in two sides of the same axle are not identical, and thus the two wheels at one axle will not be aligned in the same axis. The total dynamic responses, including those of the bounce, pitch and the roll of the PSS vehicle, to the asymmetric road excitation may exhibit different characteristics from those of a conventional vehicle. This paper presents an investigation into the comprehensive dynamic behaviour of a vehicle with the PSS, in such a road condition, on both the straight and curved roads. The study was carried out using an 18 DOF full-car model incorporating a radial-spring tyre–ground contact model and a 2D tyre–ground dynamic friction model. Results demonstrate that the total dynamic behaviour of a PSS vehicle is generally comparable with that of the conventional vehicle, while PSS exhibits significant improvement in absorbing the impact forces along the longitudinal direction when compared to the conventional suspension system. The PSS vehicle is found to be more stable than the conventional vehicle in terms of the directional performance against the disturbance of the road potholes on a straight line manoeuvre, while exhibiting a very similar handling performance on a curved line.     

Validation of Railway Vehicle Lateral Dynamics Models

The general form of the railway vehicle lateral dynamic predictions seems to have been proven. If wheels are coned, rails are of uniform cross-section, and suspensions are linear, then good predictions can be obtained. If wheels are not coned, and rail sections vary, but the suspension is relatively linear, as in modern vehicles, it is still possible to obtain good predictions of critical speed for flexible suspensions. The situation with “stiff” vehicles remains unproven. In each case dynamic response calculations will be only as good as the knowledge of the track input including the rolling line term. The validity of making calculations to predict critical speeds of very non-linear vehicles has not yet been convincingly demonstrated. Validation experiments for the more difficult case of time history representation suggest the possibility of correct prediction for easily comprehensible vehicles, but even this requires an enormous amount of supportive experimental work.     

Validation of Railway Vehicle Lateral Dynamics Models

SUMMARY

The general form of the railway vehicle lateral dynamic predictions seems to have been proven. If wheels are coned, rails are of uniform cross-section, and suspensions are linear, then good predictions can be obtained. If wheels are not coned, and rail sections vary, but the suspension is relatively linear, as in modern vehicles, it is still possible to obtain good predictions of critical speed for flexible suspensions. The situation with “stiff” vehicles remains unproven. In each case dynamic response calculations will be only as good as the knowledge of the track input including the rolling line term. The validity of making calculations to predict critical speeds of very non-linear vehicles has not yet been convincingly demonstrated. Validation experiments for the more difficult case of time history representation suggest the possibility of correct prediction for easily comprehensible vehicles, but even this requires an enormous amount of supportive experimental work.     

低滑移率条件下轮速传感器脉冲数相对差值的影响因素研究

通过对捷达轿车的道路试验,研究了汽车行驶速度、载荷及轮胎气压对轮速传感器脉冲数相对差值的影响。试验结果表明,当车速增大时,从动轮(或驱动轮)之间的脉冲数相对差值较小,而驱动轮与从动轮之间的相对差值较大;在正常载荷范围内,载荷对脉冲数相对差值影响较小;脉冲数相对差值与轮胎气压差值的变化近似成线性关系。进行间接轮胎气压监视系统设计时,可以利用脉冲数的相对差值监测轮胎气压的变化。