【作者】 曹民；

【导师】 喻凡；

【作者基本信息】 上海交通大学 ， 车辆工程， 2008， 博士

【摘要】 采用悬架高度(包括车高和座高)自动调中装置能改善悬架性能、延长机件寿命。此外,车高自动调中装置还可保持良好的车身姿态,兼具静态型前照灯自动调平装置的功用;座高自动调中装置还能保持相对稳定的座椅高度,提供良好的驾驶视野和操作条件。本文以上海市“青年科技启明星计划”资助项目(04QMX1474)为工程背景,针对传统座高和车高调节装置存在的各自不足,提出了一种具有高性价比的新型悬架高度自动调中方案,能通过全机械方式实现座高和车高的自动调中,而无须外界能量供给。为逐步、系统地考察该自动调中装置的性能特点,先后对座高和车高自动调中器进行了结构设计、实验验证、仿真分析和参数优化。全文共分五章:第一章(绪论)首先介绍了座椅悬架和车辆悬架的基本功用及性能要求;然后回顾了传统悬架高度调节装置的背景技术和研究现状,包括手动式和气动式座高调节装置、以及无源式和有源式车高自动调平装置;最后概述了本文的研究价值和研究内容。第二章(创新设计及实验验证)为弥补传统悬架高度调节装置的各自不足,提出了机械式悬架高度自动调中装置的创新设计方案。为验证该方案的可行性和有效性,先以某重型货车的驾驶员座椅悬架为研究对象,对座高自动调中悬架进行了结构设计和样机试制,并通过台架试验分析初步验证了该方案的可行性和有效性。针对座高自动调中悬架存在噪声和摩擦阻尼较大等问题,再以某轻型客车的非独立后悬架为研究对象,对车高自动调中器进行了改进设计和样机试制,并通过道路试验分析进一步验证了该方案的可行性和有效性;最后,还对原理样机的结构和性能缺陷进行了改进分析。第三章(数学建模及仿真分析)首先,按照多体动力学建模方法,建立了手动调中和自动调中座椅悬架的数学模型;为比较两种座椅悬架的性能差异,采用SimMechanics机构仿真工具,分别在扫频和正弦地板激励下对两种座椅悬架进行了时域和频域性能的仿真分析。其后,在考虑了不同载荷、非线性悬架刚度和阻尼的基础上,分别建立了普通和调中车辆悬架的单轮模型;为考察车身俯仰运动对车身姿态和前照灯照距的影响,进一步建立了两种车辆悬架的半车模型。最后,基于Simulink仿真环境,分别在随机和脉冲路面激励下对两种车辆悬架进行了时域和频域性能的仿真分析,从而得出了机械式车高自动调中悬架的主要特性。第四章(设计参数的多目标优化)根据最优化方法的基本理论,通过加权和法建立了车高自动调中器设计参数的多目标优化模型,并采用复合形法直接搜索求解出最优解;其后依据离散变量优化方法,推导出调中组件的选型设计参数,并对优化结果进行了检验和分析。从而在保证悬架性能的前提下,充分发挥了自动调中器的调中性能。第五章(全文总结)归纳了本文的主要研究结论和主要创新成果,并展望了本课题的后续研究任务。更多还原

【Abstract】 The main benefits by adopting a suspension height self-centering device have been proved in practice for many years, i.e., suspension performances can be significantly improved and component lifespan can be prolonged. Besides, the self-centering device for vehicle body height can maintain proper body attitude along with the function of self-aligning for headlights,and the self-centering device for seat height can keep steady seat height and provide good visual scope and operating condition for driver. Taking the“Youth Technological Phosphor Project”of Shanghai City (04QMX1474) as engineering background, a novel suspension height self-centering device is researched and developed in this dissertation. By analyzing the defects of the conventional self-centering devices both for seat and body height adjustment, a novel pure-mechanical scheme with high performance-price ratio is proposed which can realize the self-centering of suspension height but without the need of hydraulic and electrical system hardware and corresponding energy supply.Respectively for vehicle suspension and seat suspension, the structure design, experimental validation, simulation analysis and parameter optimization of the mechanical self-centering devices are sequently performed. The dissertation includes five chapters as follows:In the first chapter (Introduction), the basic functions and performance requirements respectively for seat suspension and vehicle suspension are introduced firstly. Then technical background, including the practical application and characteristics for different conventional height adjustable devices, such as the manually/pneumatically adjustable devices for seat height and the passive/active self-leveling devices for body height are reviewed. Finally, the significance and content of the study in this dissertation are presented.In the second chapter (Novel Design and Experimental Validation), the design scheme of the proposed mechanical self-centering device for suspension height is described in detail. Firstly, taking the driver seat suspension of a particular heavy truck as a preliminary research example, a prototype of mechanical self-centering seat suspension is developed based on the novelly-designed structure. The first-round prototype tests show that this design scheme is feasible except some problems, e.g., relatively high level of noise and friction damping. Hence, an improved design for more significant design subject, i.e., the rear independent suspension of a light bus is proposed. Based on the re-designed mechanical self-centering device for vehicle suspension, a prototype is developed for experimental study. The real road tests proved the effectiveness of the vehicle height self-centering device, so the feasibility of the design scheme is further experimentally validated. Meanwhile, the shortcomings of the prototype in terms of structures and performances are analyzed.In the third chapter (Mathematical Modeling and Simulation Analysis), respectively using multi-body system dynamics modeling method, the mathematical models for both manual-centering and self-centering seat suspensions are built firstly. In order to examine the characteristics of mechanical self-centering seat suspension and make comparison, the performances of both types of seat suspensions in frequency and time domains are analyzed by simulations in SimMechanics software environment with the typical floor-board excitations, i.e., swept and sine wave, etc. Since the body pitch angle must be concerned for body attitude with significant influence on headlight performance, a half-vehicle model respectively with/without self-centering device is established in which both spring and damping nonlinearities have been considered. By using Simulink software, the performances of both configurations with the road excitations of random and pulse are analyzed by simulations, and the main characteristics of the mechanical self-centering vehicle suspension are presented.In the fourth chapter (Multi-object Optimization of Design Parameters), a multi-object parameter design optimization model for the vehicle suspension self-centering device is built by weighted sum approach, and optimal solution is obtained by adopting compound shape approach. Then, the relevant selecting-type parameters for self-centering device components are deduced by using discrete variable optimal method. Finally, the optimal results are verified and analyzed to examine performance potentials of the designed self-centering device in condition of ensuring overall suspension performances.In the fifth chapter (Summary), the research contributions and innovation achievements in this dissertation are summarized and the further work is prospected.更多还原