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通过从理论上分析汽车制动系统的作用,从汽车动力学的角度,讨论了汽车制动过程中的功和功率,提出了科学制动汽车,延长汽车制动系统使用寿命的一般方法。 相似文献
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利用简化的半挂汽车列车弯道制动力学模型,分析了车辆参数,使用因素对汽车弯道制动效能的影响,并用实车弯道制动效能试验进行了验证。 相似文献
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分析汽车在行驶过程中的制动状况是一个很复杂的问题,制动过程中不同车轮抱死将对汽车造成极大危害。传统的防止措施是采用制动力调节装置。随着汽车性能的不断提高,对制动法规的要求也愈苛刻。近年来汽车制动防抱死装置在汽车上得到广泛应用。本文通过引入轮胎滑动率的概念,对几种制动状况进行分析。介绍了汽车制动防抱死系统工作原理、组成及特点。 相似文献
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本文分析了汽车车轮制动瞬态动力学,结合精确的15自由度空间刚体动力学模型,定量地分析了车轮抱死松开所获得的加减速度值,并为防抱制动提供了准确的加减速度阈值,同时考虑到防抱制动系统本身装置的特性,提出了最佳又符合实际的制动矩控制参数,使用仿真结果更接近实际,为电子防抱制动系统的研究提供较完整的理论体系和分析方法,并开发了汽车电子防抱制动系统模型(HVOSM-ABS)及模拟程序,该程序具有16种不同的 相似文献
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本文建立了汽车在安装自适应机械式制动防抱死装置MABS(Mechanical Adaptive Braking Set)时的制动油压模型,分析了MABS的起振压力及振动频率对汽车制动性能的影响,为正确使用MABS来改善汽车制动性能提供了理论基础。 相似文献
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通过对半挂汽车列车制动时的动力学分析,推导出半挂汽车列车产生折叠和甩尾的动力学方程式,对影响半挂汽车列车制动稳定性的有关因素进行分析。 相似文献
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汽车防抱死制动系统(Anti-lock Braking System,ABS)的作用是确保汽车制动时行驶方向的稳定性、可靠性,但是目前仍存在非线性、时变性以及参数不确定性等问题。为保证汽车制动行驶过程中的操纵稳定性和安全性,进一步实现各工况下防抱死制动系统的优化控制,以影响整车稳定的变量滑移率为研究对象,分析所设计策略的控制效果。搭建汽车动力学模型、制动系统模型、轮胎模型和滑移率模型等主要模型,设计基于滑移率的ABS二阶非线性自抗扰控制器。运用MATLAB/Simulink软件对基于自抗扰控制(Active Disturbance Rejection Control,ADRC)的ABS制动过程和基于模糊PID控制的ABS制动过程进行仿真,对比研究最佳滑移率、载荷、水泥-冰对接路面、扰动等对制动过程中的轮速、车速以及滑移率等动态性征反映的稳定性和抗扰能力的影响,同时研究其对最终制动距离和最终制动时间反映的制动性能的影响。最后,将自抗扰控制器和模糊PID控制器装配于试验车辆的ABS,进行水泥路面和冰-水泥对接路面制动过程的实车试验。研究结果表明:基于二阶非线性自抗扰控制算法的ABS制动的最终制动距离和最终制动时间更短、制动效果更优,制动过程中的轮速、车速和滑移率在响应速度、稳定性和抗扰能力等方面均更佳;试验结果与仿真结果吻合,证明了仿真模型及其仿真结果的可行性和正确性。 相似文献
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《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(4):271-284
Summary A flat track tire testing machine developed by the IMMa group is described. It permits the simulation and study of the dynamic behavior of a great variety of tires under controllable and repetitive highly dynamic realistic working conditions in the laboratory for a diversity of vehicles, from motorcycles to light trucks. The machine incorporates: – a hydraulically operated tire support and loading system with wide operating ranges; – a computer controlled brake system to simulate braking maneuvers with ABS systems; – a complete sensorial system; – a data acquisition and control system continually monitoring and acting on the experimental variables, i.e., tire and belt speed, longitudinal slip, slip and camber angles, tire pressure, tire normal force, etc. As an application example, results are presented that adjust the parameter of the magic formula for a standard 175/70 R14 passenger vehicle tire. Accurate mathematical tire models are recognized as essential for the prediction of vehicle dynamic performances using simulation tools. 相似文献
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A Versatile Flat Track Tire Testing Machine 总被引:1,自引:0,他引:1
J. A. Cabrera A. Ortí z A. Sim n F. Garcí a A. P rez La Blanca 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2003,40(4):271-284
Summary A flat track tire testing machine developed by the IMMa group is described. It permits the simulation and study of the dynamic behavior of a great variety of tires under controllable and repetitive highly dynamic realistic working conditions in the laboratory for a diversity of vehicles, from motorcycles to light trucks. The machine incorporates: - a hydraulically operated tire support and loading system with wide operating ranges; - a computer controlled brake system to simulate braking maneuvers with ABS systems; - a complete sensorial system; - a data acquisition and control system continually monitoring and acting on the experimental variables, i.e., tire and belt speed, longitudinal slip, slip and camber angles, tire pressure, tire normal force, etc. As an application example, results are presented that adjust the parameter of the magic formula for a standard 175/70 R14 passenger vehicle tire. Accurate mathematical tire models are recognized as essential for the prediction of vehicle dynamic performances using simulation tools. 相似文献
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Nonlinear Dynamics of Vehicle Traction 总被引:3,自引:0,他引:3
B. J. Olson S. W. Shaw G. St p n 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2003,40(6):377-399
Summary The purpose of this study is to understand the nonlinear dynamics of longitudinal ground vehicle traction. Specifically, single-wheel models of rubber-tired automobiles under straight-ahead braking and acceleration conditions are investigated in detail. Customarily, the forward vehicle speed and the rotational rate of the tire/wheel are taken as dynamic states. This paper motivates an alternative formulation in which wheel slip, a dimensionless measure of the difference between the vehicle speed and the circumferential speed of the tire relative to the wheel center, replaces the angular velocity of the tire/wheel as a dynamic state. This formulation offers new insight into the dynamic behavior of vehicle traction. The unique features of the modeling approach allow one to capture the full range of dynamic responses of the single-wheel traction models in a relatively simple geometric manner. The models developed here may also be useful for developing and implementing anti-lock brake and traction control control schemes. 相似文献
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《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(6):377-399
Summary The purpose of this study is to understand the nonlinear dynamics of longitudinal ground vehicle traction. Specifically, single-wheel models of rubber-tired automobiles under straight-ahead braking and acceleration conditions are investigated in detail. Customarily, the forward vehicle speed and the rotational rate of the tire/wheel are taken as dynamic states. This paper motivates an alternative formulation in which wheel slip, a dimensionless measure of the difference between the vehicle speed and the circumferential speed of the tire relative to the wheel center, replaces the angular velocity of the tire/wheel as a dynamic state. This formulation offers new insight into the dynamic behavior of vehicle traction. The unique features of the modeling approach allow one to capture the full range of dynamic responses of the single-wheel traction models in a relatively simple geometric manner. The models developed here may also be useful for developing and implementing anti-lock brake and traction control control schemes. 相似文献
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R. S. Vieira L. C. Nicolazzi N. Roqueiro 《International Journal of Automotive Technology》2012,13(4):553-562
When considering vehicle safety, tires and all that they represent are a fundamental topic. Tire studies have received a considerable amount of attention from the research community because their improvement has a direct and strong impact on vehicle handling and braking. Within this eld of analysis lies an important behavioral feature: the tire slip angle, which is a consequence of lateral forces acting on the tire. This characteristic is predicted in some cases and evaluated experimentally in others. This paper addresses another way to assess the slip angle. We propose a mathematical model that describes a constraint linking the slip angle and steering angle that make a vehicle turn. We present a simplied kinematic model (based on the classic bicycle model) and a four-wheel model, which makes all of the angles involved compatible with each other. In our case, the match will be given by the determination of the turning radius. Two different scenarios, understeering and oversteering vehicles, were simulated, and the results and conclusions reached are presented herein. 相似文献
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In a dynamic vehicle simulation, longitudinal tire force is primarily based on the longitudinal slip (ratio). In the longitudinal
slip formula, state variables are used in the denominator. This causes a divergence problem for numerical simulations of vehicle
dynamics. To avoid this numerical singularity, a differential slip calculation method was developed for use in dynamic vehicle
simulations. However, this method also causes a singularity when the wheel velocity approaches zero in a pure slip state,
such as during sudden braking. In this paper, a new longitudinal slip calculation method, which can overcome singularities
in all velocity conditions, is proposed. For this purpose, the Taylor series is adapted to the slip formula and the idea of
virtual wheel rotation stiffness is introduced for the development of the slip equation. The physical phenomenon at the zero
slip state is analyzed. Finally, the proposed slip formula is used to solve the numerical singularity problem, and the non-singular
slip (NSS) calculation method is proposed. The proposed NSS method is applied to tire model performance test (TMPT) simulations
to validate its performance. 相似文献
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制动—驱动工况下的轮胎侧偏特性理论研究 总被引:2,自引:0,他引:2
本文通过考虑制动和驱动工况下的轮胎印迹内垂直载荷分布的不同,建立了比以往模型更完善的制动-驱动工况下的轮胎侧偏特性理论模型,以6.50R16轮胎为例,分析了滑移率,侧偏角和垂直载荷分布形状参数等对其侧特性的影响。 相似文献
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分析了各种常用轮胎模型的特点与应用范围,根据汽车操纵动力学研究的需求,在Matlab环境下运用魔术公式建立了轮胎动力学模型,并对汽车轮胎力与纵向滑移率,纵向力、侧向力及回正力矩与纵向滑移率、侧偏角、外倾角、垂直载荷的关系等轮胎特性进行了仿真分析,实验结果表明,魔术公式轮胎动力学模型可以较好地模拟轮胎的动力学特性,适用于车辆动力学研究领域。 相似文献