电驱动系统可靠性目标载荷快速构建方法研究

目标载荷是有效开展车辆可靠性评估与寿命预测的基础。车辆行驶过程中,由于驾驶行为、路面起伏、载重状态等因素的不断变化,不同用户电驱动系统载荷差异巨大,如何构建覆盖一定用户百分位水平的电驱动系统可靠性目标载荷,是当前产品高质量开发面临的共性问题。以用户历史运行数据为基础,结合整车动力学仿真和参数优化,提出了一种电驱动系统可靠性目标载荷快速构建方法。针对车辆行驶过程中道路坡度与整车质量参数数据难以精确获取、不同用户数据差异大的现实,通过等效坡度和等效质量的参数优化,提高电驱动系统载荷仿真精度;针对不同用户间等效坡度和等效质量差异,以95%用户损伤水平为目标,通过多目标优化得到群体用户模型参数的等效统一解;基于整车动力学仿真与实际用户载荷时域及损伤域对比,验证电驱系统可靠性目标载荷的有效性。结果表明,基于得到的统一参数仿真载荷与95百分位用户损伤误差仅为1.09%,为有效开展电驱动系统可靠性评估提供技术支持,为整车及其它系统可靠性目标载荷构建提供参考。

A Method of Rapid Construction of Reliability Target Load for Electric Drive Systems

Target load is crucial for vehicle reliability assessment and life prediction. While the vehicle is in motion, due to the continuous changes in driving behavior, road undulations, load status and other factors, the electric drive system load varies greatly among different users. Therefore, the key is to construct the reliability target load of the electric drive system suitable for a certain percentage of all users. Based on the historical operating data, combining vehicle dynamics simulation and parameter optimization, the paper proposes a method to quickly construct the reliability target load of the electric drive system. Due to the difficulty to obtain accurate data of road gradient and vehicle parameters during the driving process, and the wide variety of data for different users, the parameter optimization was performed to obtain the equivalent slope and the equivalent vehicle mass in the load simulation.The multi-objective optimization was conducted by taking the 95% customer damage level as the target and the equivalent unified solution was obtained. Based on the comparison between the vehicle dynamics simulation results and the actual customer load in both time domain and damage domain, the paper verified the reliability target load of the electric drive system. The results show that the error between the obtained load from the simulation and the 95th percentile customer damage level is only 1.09%. The paper provides a reference for effective development of the reliability evaluation of the electric drive systemand for construction of the reliability target load of the whole vehicle.