【作者】 陈晓洁；

【导师】 刘胜；

【作者基本信息】 华中科技大学 ， 机械制造及其自动化， 2013， 博士

【摘要】 目前对乘用轿车胎压监测系统（Tire Prssure Monitoring System，TPMS）的研究较多，而对商用客车TPMS的研究相对较少，商用客车的TPMS存在系统可靠性差和信号传输不稳定的问题。为提高商用客车TPMS的可靠性和无线传输性能，本文进行了组态天线的仿真与设计、旋转部件电磁波传播模型、系统控制软件及算法等方面的研究。主要研究内容包括：（1）综合考虑旋转天线、轮毂、车身以及非理想地面的影响，提出组态天线的概念。构建和研究组态天线的电磁场仿真模型，通过仿真的结果来优化组态天线的匹配电路设计，以提高无线传输性能。仿真结果表明：组态天线在不同方向上辐射能力的差异比单天线的大，且天线的方向图存在一些零点；非理想地面组态天线在最大辐射方向上的功率值比理想地面的小，且天线功率方向图的变化主要是受到不同地面电导率变化的影响；当地面粗糙度在8cm以上时，地面粗糙度对组态天线性能的影响开始显现；旋转过程中组态天线增益的变化范围较大，输入阻抗的电阻部分相对变化较大而电抗部分相对变化不大，必须进行阻抗匹配设计。测试结果表明：采用组态天线阻抗匹配设计后的TPMS的数据帧接收正确率在90%以上。（2）推导和建立旋转部件电磁波绕射传播模型，并进行仿真分析，仿真结果表明：路径损耗随着旋转角度的变化而变化，路径损耗还与旋转部件半径、工作频率、旋转速度、收发端之间距离、透明孔径尺寸以及天线高度等参数有关。考虑直射波和反射波的路程差、旋转运动速度变化和入射波方向变化导致的多普勒频移，推导和建立了旋转部件双径传播模型，仿真结果表明：路径损耗随着旋转角度的变化而变化，平行极化波的路径损耗波动范围和幅度比垂直极化波小，路径损耗还与旋转部件半径、工作频率、旋转速度、收发端之间距离、介电常数以及天线高度等参数有关。分别对天线置于商用客车驾驶室内的绕射路径损耗、天线置于底盘上的绕射路径损耗以及双径传播路径损耗进行仿真分析，仿真结果表明：总体而言接收天线置于底盘上的路径损耗比置于驾驶室内的要小，建议在车底布放接收天线，天线尽可能靠近轮胎，以保证接收效果。搭建测试平台进行旋转部件路径损耗测试，测试结果表明本文提出的分析方法和建立的传播模型接近实际情况，具有合理性。（3）对TPMS系统的控制软件及算法进行研究，包括高低频通讯协议、软件流程，提出信号调理算法、低温环境下的温度补偿和软件滤波算法，并详细阐述了软件抗干扰设计的关键点，设计了预防误报警策略。更多还原

【Abstract】 Currently more research efforts are focused on the tire pressure monitoring system(TPMS) of passenger cars, however, research on TPMS of commercial buses has been rare.The TPMS of commercial buses have problems of poor reliability and unstable signaltransmission. In order to improve the reliability and wireless transmission performance ofTPMS of commercial buses, simulation and design of the configuration antenna,electromagnetic wave propagation model of rotating component, system control softwareand algorithms are studied in this dissertation. Main research tasks include the following.Comprehensively considering the impacts of rotating antenna, wheel, vehicle bodyand non-ideal ground, the concept of configuration antenna is proposed. Through buildingthe electromagnetic field simulation model, the antenna parameters in simulation are usedto optimize the design of antenna matched circuit and to improve the performance ofwireless transmission. The simulation results indicate that radiation variations in differentdirections of configuration antenna are bigger than that of single antenna, and antennaradiation pattern has several zero points. The power of configuration antenna in maximalradiation direction on non-ideal ground is smaller than that of on ideal ground, and antennapower pattern is mainly influenced by the conductivity changes of different grounds. Whenground roughness is more than8cm, the influence on configuration antenna performanceemerges. During rotating, for configuration antenna, the fluctuation of gain is apparent, theresistance part of input impedance changes significantly while change of reactance part isminor, impedance matching design is therefore necessary. The experiment shows that thereceiving probabilities are more than90percent after using configuration antennaimpedance matching design.An electromagnetic wave diffraction propagation model of rotating component isdeduced and established, and simulation analysis is conducted. Simulation results showthat the path loss varies with the rotation angles, the path loss is related with parameters ofrotating component radius, working frequency, rotating velocity, the distance betweentransmitter and receiver, transparent aperture size and antenna height. Considering the distance difference between the direct propagation path and reflection propagation path aswell as Doppler frequency shift caused by changes of rotation velocity and incident wavedirection, a dual-path propagation model of rotating component is deduced and set up.Simulation results show that the path loss varies with the rotation angles, and thefluctuation range and magnitude of path loss of the parallel polarized wave is smaller thanthe vertical polarized wave. The path loss has relationships with rotating component radius,working frequency, rotation velocity, the distance between transmitter and receiver,dielectric constant as well as antenna height. The diffraction path loss of antenna placed inthe cab or on chassis of commercial bus, and the path loss of dual-path propagation aresimulated. Results indicate that the path loss of antenna on chassis is smaller than that of inthe cab. It is suggested that it is better to place antenna on chassis and near the tire as muchas possible to ensure the receiving performance. In order to verify the propagation model,path loss test of rotating component is carried out, and the results show that the presentedmethod and established propagation model are close to actual situation and reasonable.Control software and algorithms of TPMS system are studied. High frequency and lowfrequency communication protocols, software process, signal conditioning algorithm, thealgorithm of the temperature compensation and software filter in low temperature conditionare proposed. Key points of software anti-interference design are elaborated, and theprevention strategy for false alarm is designed.更多还原