基于半车模型的轮毂驱动车辆簧下质量影响研究  

Research on the unsprung mass effect of in-wheel motor drives based on a half-vehicle model

作　　者：吴佩宝 罗荣康 俞志豪 侯之超[1] WU Peibao;LUO Rongkang;YU Zhihao;HOU Zhichao(School of Vehicle and Mobility,Tsinghua University,Beijing 100084,China)

机构地区：[1]清华大学车辆与运载学院,北京100084

出　　处：《清华大学学报（自然科学版）》2024年第8期1445-1455,共11页Journal of Tsinghua University(Science and Technology)

摘　　要：轮毂电机驱动作为一种新型的电动汽车构型,其簧下质量过大对车辆动力学性能的影响是一个备受关注的问题。该文基于半车模型,推导了车辆平顺性典型评价指标的幅频特性和均方根值。在传统车辆模型的前后车轮上附加质量,构建轮毂电机驱动车辆模型,考虑车速、车身位置、电机质量及轮毂电机驱动方式等因素分别开展仿真计算。通过对比,系统分析了簧下质量增加对车辆平顺性的影响规律,并在频域中对影响机理进行了解释。结果表明,在1~50m/s(3.6~180km/h)的车速范围内,簧下质量增加同时恶化了车轮相对动载荷和悬架动挠度指标。然而,由于轴距滤波效应,簧下质量增加对车身加速度的影响则随位置改变而呈现不同的特征:前后车身加速度指标在所有车速下均被恶化,而质心加速度和俯仰角加速度指标则均随车速呈现交替恶化和改善的特点,且两个指标的变化趋势正好相反。此外,相比轮毂电机前驱和四驱布置,轮毂电机后驱布置在常用车速下引起的车辆舒适性恶化程度较小。[Objective]In-wheel motor drive has emerged as a promising innovation in electric-vehicle-powertrain configurations.In mainstream configurations of in-wheel motor drive units,power and transmission devices are rigidly connected to wheel hubs.However,this design increases the unsprung mass of the vehicle.The implications of this added mass on vehicle performance,especially in terms of ride comfort,have been a subject of debate.Existing research,encompassing experimental and simulation studies,presents different and sometimes contradictory conclusions.Notably,many simulations fail to consider the effects of motor positioning and resultant vibrations across different areas of the vehicle.[Methods]This study tries to address these concerns using a half-vehicle model approach.These models are established for a standard passenger vehicle and an in-wheel motor-driven variant,the latter modified by adding mass to the wheels of the former.To assess ride comfort,we focused on several dynamic performance indicators:body vertical acceleration,pitch angular acceleration,relative wheel dynamic load,and suspension travel.Using the frequency domain method allowed us to convert double-wheel excitations into single-wheel excitations,from which we derived the equivalent amplitude-frequency characteristics for our chosen indicators.This step was followed by determining the power spectral density of a random road profile,which in turn facilitated the calculation of the power spectral density and root-mean-square values of the performance indicators.Simulations were then performed to compare the performance of the in-wheel motor-driven vehicle with that of the traditional vehicle on a C-class random road over a speed range varying from 1 to 50 m/s(3.6-180 km/h).The analysis considered various factors,including body position,hub motor mass,and hub motor drive mode.By integrating the amplitude-frequency characteristics of our indicators,we were able to shed light on how increased unsprung mass influences vehicle dynamics.[Results]The re

关 键 词：簧下质量 车辆平顺性 轴距滤波效应 轮毂电机驱动方式 

分 类 号：U461.4[机械工程—车辆工程]