【作者】 邹喜红；

【导师】 柯坚； 石晓辉；

【作者基本信息】 西南交通大学 ， 驱动技术与智能系统， 2010， 博士

【摘要】 摩托车平顺性是摩托车的重要性能之一。目前,国内摩托车在NVH性能方面与国外差距很大。在摩托车平顺性仿真方面主要采用正弦、阶跃和B级路面等标准信号作为激励,这与实际情况相差较大。道路模拟能在室内再现摩托车实际道路行驶时的振动情况,具有重复性好,安全性高等特点。因此,结合CAD/CAE技术和道路模拟试验技术,对摩托车平顺性进行研究具有重要的理论意义和工程应用价值。论文在查阅国内外相关研究文献并详细分析摩托车道路模拟试验技术、摩托车虚拟样机技术和摩托车平顺性评价方法等方面的研究热点及存在的问题基础上,优化了摩托车道路模拟试验方法,提出了基于道路模拟的摩托车平顺性仿真分析方法和基于速度与频率加权的摩托车平顺性客观评价方法,为摩托车开发提供了重要的手段。首先,在分析远程参数控制(RPC)原理、道路模拟试验方法及关键技术基础上,建立了两通道轮胎耦合式摩托车道路模拟试验平台,对摩托车道路模拟试验进行了优化。采用优化的试验方案,模拟迭代精度和稳定性明显提高,在室内精确再现了道路载荷谱；通过合理布置加速度和应变信号测点,对多款车型在海南试验场、典型水泥路和碎石路上进行了多工况道路载荷谱采集,建立了国内典型路面摩托车道路载荷谱数据库；采用统计分析、滤波等方法对道路载荷谱进行分析和处理,选取前后轴加速度为期望响应信号,进行了大量模拟迭代和模拟试验,获取了代表摩托车实际行驶振动情况的道路模拟激励谱。其次,以某125摩托车为例,结合虚拟样机技术和道路模拟试验技术,建立了摩托车5自由度振动分析模型和摩托车刚柔耦合平顺性仿真平台。一方面,建立了摩托车5自由度线性理论分析模型,运用拉格朗日方法推导了系统运动微分方程和空间状态方程,为摩托车振动分析提供了重要的理论基础。另一方面,建立了摩托车车架有限元模型,应用兰索士法进行模态分析,提取了车架空间柔性体模型,并进行了试验模态频率相关分析和模态置信准则验证；在考虑车架、减振器和轮胎等零部件非线性特性基础上,开发了摩托车人-车刚柔耦合平顺性仿真模型；通过在前后轮添加测试平台,建立了能真实反映摩托车实际行驶振动情况的人-车-路平顺性仿真平台。在此基础上,基于凸块路面和实际道路谱输入对摩托车平顺性进行了仿真分析,建立了摩托车平顺性仿真验证评估方法,并提出了摩托车平顺性改进意见。借助建立的摩托车5自由度振动分析模型和摩托车刚柔耦合平顺性仿真平台,以凸块路面和实际道路谱为输入,分别进行了仿真分析；应用摩托车道路模拟试验机,在相同输入下进行了试验,以功率谱密度曲线、时域绝对值最大值和信号平均功率对仿真结果进行了定性和定量综合评估,仿真结果和试验结果具有很好的一致性：根据试验结果和仿真结果,对摩托车振动特性进行了分析,并提出了改进意见。最后,在分析现有摩托车平顺性评价方法及车速与加速度响应关系基础上,提出了基于速度和频率加权的摩托车平顺性评价方法,解决了不同车速评价结果不同的矛盾。通过大量试验数据,发现摩托车在碎石路和水泥路上行驶时车速服从一定参数的贝塔分布,采用直接优化参数估计法进行了参数估计,得到了车速加权系数；结合ISO2631和ISO5349中的频率加权系数,采用MATLAB编制程序,计算速度和频率加权加速度均方根值,对摩托车平顺性进行了综合评价。结果表明,速度和频率加权加速度均方根值是各种车速下频率加权加速度均方根值的综合反映。更多还原

【Abstract】 Ride comfort is an important characteristic of motorcycle. At present, the domestic-made motorcycle’s performance in NVH has a large gap with foreign products. In terms of simulation of motorcycle ride comfort, the excitation is standard signals, such as sine, step and grade B road, which has much difference to actual situation. Road simulation can reproduce motorcycle vibration of actual running conditions, and has good repeatability and high security characteristics. So study on motorcycle comfort combined with CAD/CAE and road simulation is necessary and meaningful whether theorily or practically.The thesis consulted lots of research literatures home and abroad, and analyzed research focuses and problems of road simulation test technique, virtual prototype technique and evaluation method of motorcycle. Based on this, the method of motorcycle road simulation test was optimized, and the simulation method based on road simulation and evaluation method based on speed and frequency weighting of motorcycle ride comfort were put forward. Studies have provided an effective way for motorcycle development.Firstly, by analyzing the principle of remote parameter control and key technology of road simulation test in detail, the platform of motorcycle road simulation test, which is two channels tire-coupling type, was developed, and motorcycle road simulation test was optimized. With the optimized test project, the precision and stability of iteration were greatly improved, and the road load spectrum was accurately reproduced in doors. Through disposing transducer of acceleration and strain, the road load spectrums of several motorcycles were acquired when running on Hainan Proving Ground, typical gravel and concrete road at different speed, then database of motorcycle road load spectrum was established. Using statistcal algorithm and filter to analyze load spectrum, and selecting acceleration of front and rear axles as despired response signal, simulation iteration and simulation test were implemented, at the same time excition spectrum of road simulation which represents actual road was obtained.Secondly, taking some 125 motorcycle as example, the 5-DOF vibration model and rigid-flexible coupling simulation platform of motorcycle were developed by combined with virtual protype and road simulation. On the one hand, the 5-DOF multi-body dynamic model was built. Also, the differential equation of motion and state-space formulation were derived according to Lagrange Equation, which provided an important theoretical fundament for vibration analysis of motorcycle. On the other hand, the 3-D finite element model of frame was built. By using Lanczos method, the flexible model of frame was obtained, and the analysis of frenquecy correlation and modal assurance criteria showed that the flexible model is correct. Taking into account non-linear characteristic of frame, absorber and tire, the rigid-flexible coupling simulation model of motorcycle ride comfort was developed, then the simulation platform which can reproduce actual vibration condition of motorcycle was created finally.On the basis of 5-DOF vibration model and rigid-flexible coupling simulation platform, the ride comfort of motorcycle was simulated with the pulse road and actual road spectrum as excitation respectively, at the same time the verification and evaluation methods were put forward. Through inputing same excitation into road simulator, the experiments were implemented, and the simulation results were qualitatively and quantitatively evaluated with PSD curve, maximum absolute value and average power. The study showed that simulation results and experimental results matched very well. According to the response signals, the vibration characteristic of the motorcycle was discussed, and some improving suggestions about ride comfort were presented.Finally, the thesis analyzed existing evaluation method of motorcycle ride comfort and relation between motorcycle speed and response in detail. Then a new evaluation method of motorcycle ride comfort based on speed and frequency weighting was put forward, which solved the conflict that the evaluation result is different when speed varieties. Lots of test datum showed that when motorcycle runs on gravel and concrete road, the speed obeys 3 distribution, and the parameters ofβdistribution were estimated by experimental datum. Combined with ISO 2631 and ISO 5349, the speed and frequency weighted RMS of acceleration was computed by MATLAB program, and ride comfort of the motorcycle was estimated effectively. The result showed that speed and frequency weighted RMS of acceleration is the synthetical reflection of RMS of acceleration at different speed.更多还原