Estimation of Vehicle Speed Based on Wheel Speeds from ASR System in Four-Wheel Drive Vehicles

Three major methods currently in the use of determining vehicle speed based on wheel speeds,the minimum wheel speed,minimum wheel speed corrected by slope method and the Kalman filter method,are analyzed,with merits and defects of each approach stated. Through simulations,the Kalman filter method based on minimum wheel speed shows improved accuracy,in addition to better adaptivity to vehicle reference speed. It also can be used to acceleration ship regulation (ASR) in part-time four-wheel drive vehicles.     

Vehicle Dynamics Modeling and Simulation for ACC

A 7 degree-of-freedom (DOF) 4 wheels vehicle dynamics model based on Matlab-Simulink is established,and 7 DOF vehicle dynamics equations in the form of nonlinear state-space standards are given.The characters of the electronic throttle and the active braking system have been analyzed.And the electronic throttle model and the active braking system model are built according to the test results respectively.Off-line simulation results indicate that the model is suitable for the vehicle adaptive cruise control ...     

基于MC9S12DP256的汽车ABS数据采集系统设计

设计了基于MC9S12DP256单片机的汽车ABS数据采集系统;详细介绍了该系统的硬件电路以及系统软件设计.大量的ABS实车实验证明:该数据采集系统工作性能良好,可靠性高.采集数据的精度完全可以满足汽车ABS系统的要求.     

Road identification method based on angular acceleration of vehicle driving wheel

The fundamental principle of road identification by using angular acceleration of driving wheels was demonstrated in this paper. Based on the analysis of energy conversion and parameters variation during the vehicle drive slip process, the change of adhesion coefficient relative to the angular acceleration were theoretically studied experimentally validated. The variation shows that the change of adhesion coefficient relative to the angular acceleration and the change of slip ratio in the drive slip process have same trend-both of them exist an only optimal angular acceleration corresponding to the peak value of adhesion coefficient. The peak adhesion coefficient of the prototype vehicle is about 0.14 on the ice-covered road surfaces, with the corresponding optimal angular acceleration of about 23.5 rad/s2 and optimal slip ratio of about 9.4%.     

3种基于HCS12定时器的PWM波形发生器的设计

在车辆ASR系统开发中,提出了基于HCS12单片机增强型定时器复用I/O输出PWM信号的开发方案,解决了由于硬件限制导致PWM输出通道的不足的问题。介绍了单片机增强定时器通过输出比较寄存器、输出比较中断、TCNT输出翻转实现PWM波形输出的3种方法,详述了各方法中重要寄存器的设置和逻辑对应关系,并给出了相应的波形输出图和程序流程图,通过理论分析和实验结果探讨了不同设计方案的优缺点。     

车辆驾驶员辅助系统中基于运动模型的前车最优跟随控制

为解决驾驶员辅助系统在前车跟随控制中车距与车速误差不易同步收敛的问题,建立考虑主车对期望加速度动态响应的主车与前车运动模型,以对前车跟随控制提供模型参考。基于主车实际运动与理想前车跟随行驶间的偏差建立前车跟随误差模型,并用线性二次型调节器求解最优期望加速度控制序列,以作为前车跟随控制中主车运动参数控制的输出。为考虑在实车控制中车辆及环境参数发生变化的可能,在前车跟随误差模型中引入车距与车速误差累积项以使线性二次型调节器具有积分控制功能,以在实际车辆与理想模型发生偏差时仍可进行有效控制。仿真对比及实车试验证明,基于运动模型的前车跟随控制可使主车车距与车速误差同步收敛并有效减少主车达到稳态前车跟随行驶的时间,同时易于在实车控制中展开应用。     

轮式拖拉机转向梯形设计中几个问题的探讨

本文对轮式拖拉机转向梯形设计中所涉及到的理论无侧滑转向方程参数M和L及转向梯形机构基本参数M′、m和r在经过充分地分析论证后给出了明确的合理的定义。同时本文又在考虑转向节立轴内倾后,在三维空间里推导并建立了新的更准确的转向梯形运动关系的数学模型。     

拖拉机变速箱齿轮副优化设计

根据我国和南斯拉夫在拖拉机变速箱的设计、制造、使用、维修方面的经验,考虑到以前资料中所提供的变速箱优化目标函数的某些不足,本文提出了新的优化目标函数,即给弯曲疲劳强度足够的重视后,使弯曲疲劳强度和接触疲劳强度相等。这样就延长了拖拉机变速箱的使用寿命。     

拖拉机变速箱齿轮CAD

提供三种齿轮变位系数和的计算分配方法以提高拖拉机变速箱齿轮的承载能力。导出了齿宽计算的迭代公式。据此,编制了一套程序,能方便的得出齿轮设计、制造和检验中所需的数据。     

汽车ACC雷达技术的应用与发展

介绍了汽车自适应巡航系统（ACC）系统关键技术之一的车载防撞雷达技术的发展历史和国内外的应用现状。基于汽车自适应巡航系统的功能特点，阐述了车载防撞雷达的基本性能要求与当前研究的热点。详述了车用毫米波FMCW雷达和激光雷达的基本结构、工作原理以及技术特点，从雷达的探测性能、环境依赖性、工作叮靠性、处理速度与成本等方面比较了它们应用于ACC系统的优势与劣势，并对汽车ACC雷达技术今后的发展趋势进行了展望。