基于Zigbee和CAN总线的嵌入式车辆功率测试系统设计

目前车辆传动系统功率测试系统中转速测量精度基本达到要求,扭矩测量精度还未达到要求.为此提出了一种新型嵌入式无线功率测试系统的设计思想和方法,系统主要采集传动系统扭矩、转速、弯矩、扭振等参数,数据采集部分采用ARM7微处理器和Zigbee无线通信模块LW 1151,数据传输方式采用基于ARM9的CAN总线传输.通过分析计算弹性传动轴上的弯矩、扭振而引起的附加扭矩的大小,更加精确地得出车辆的轴功率,实车实验结果表明该方法可行可靠,系统达到了预期效果.     

基于脉冲位置调制的扭振信号分析方法

针对发动机轴系的扭转振动会导致发动机、传动系统和车架的振动,激发噪声,从而影响汽车行驶的安全性和平顺性的问题,在扭振信号分析的基础上,研究如何从脉冲位置调制信号(PPM)中获取角速度的波动量,并提出一种利用插值法进行离散傅立叶变换(DFT),实现扭振信号频谱分析的方法.在台架实验中,借助于虚拟仪器技术和Matlab工具,对实测的扭振信号进行处理与分析.通过与专业扭振测试仪器的测试结果对比,证实了该方法的可行性.     

机床传动系统扭转振动的矩阵计算与分析

机床传动系统扭转振动的研究是机床学的重要课题之一。本文作者将分支系统扭转振动的广义特征值问题,先化成普通特征值问题,再用雅可比方法求解其特征值和特征向量。这种计算方法较传统的霍尔兹法计算速度快得多,并且更适用于多分支系统。利用这种方法计算了Y38滚齿机传动系统扭振的固有频率及其振型。计算结果与实测数据是一致的。在此基础上,作者以数字电子计算机为工具,就传动系统各种结构参数的变化对扭振固有频率及其振型的影响作了一一分析,并由此得出了有价值的结论。本文提供的计算多分支系统特征值和特征向量的方法和程序,以及利用电子计算机分析各种参数变化对传动系统扭振的影响的方法,对其他多分支机械传动系统都不失其一般性。本文就 Y38滚齿机所作的扭振分析对齿轮机床的设计与研究有直接的现实意义。     

某货车动力传动系扭振模型的建立及分析

针对某轻型货车的动力传动系统,建立多自由度无阻尼离散化当量扭转振动模型,采用广义Jacobi算法计算扭振系统的固有频率和固有振型。对动力传动系统进行集中质量的划分,确定扭转振动模型的转动惯量和扭转刚度参数。利用Matlab的计算程序进行扭转振动计算。通过实测与计算结果的比较,验证了模型的准确性。     

齿轮传动系统扭振特性的灵敏度分析

本文研究了齿轮传动系统扭振固有频率及频响函数的设计灵敏度问题。对齿轮传动系统扭振动力学控制方程中时变的齿轮啮合刚度进行了分解．推导了系统扭振固有频率及频响函数相对于设计参数的灵敏度计算公式，这些设计参数可以是轴的扭转刚度、齿轮平均啮合刚度、阻尼及齿轮转动惯量等。这一方法可用于齿轮传动系统动力学优化设计。     

车辆多级行星传动系统强迫扭转振动与动载特性

针对某车辆行星传动系统,以发动机动态转矩为激励,采用集中参数法建立纯扭转强迫振动模型,利用拉格朗日方程建立系统微分方程并进行求解。分析了各部件在同一档位的振幅特性,得出不同部件的振动特点。研究了不同档位下行星排的振动,得出行星排在空载与受载时扭振的差异。最后对行星排啮合力波动量和动载荷系数进行计算,为行星传动系统设计和动态分析提供了依据。     

CSP热连轧机主传动系统扭振分析

针对邯钢CSP轧机的F3精机在生产中产生的振动问题,利用MATLAB软件对F3轧机主传动系统进行数值模拟,得到主传动系统的前三阶固有频率和主振型的参数,结合现场测试数据,确定了引起主传动系统共振的固有频率,结果表明系统的第3阶频率与现场测试的减速机与齿轮座之间的弧形齿联轴器的振动频率相近,弧形齿联轴器的间隙对系统的扭振产生具有很大的影响,因此减小弧形齿联轴器的间隙对抑制轧机的异常振动有重要意义。     

BJ212汽车动力传动系统扭转振动的研究

本文介绍了BJ212汽车动力传动系统扭转振动研究的工作概况。文中叙述了力学模型的建立,基本参数的测定,系统固有频率和振型的计算,系统扭振特性的台架试验,扭振减振器的设计和装车试验;分析了扭振减振器参数选择的方法,认为以相对转角β为参数选择的出发点比较合理,利于保证摩擦耗能器的减振作用,并由试验结果得到证实;最后还分析了用飞轮瞬时角速度信号表征系统扭振的试验方法。     

轧钢机主传动系统扭振故障分析与监测

在测量和计算了产生轧钢机主传动系统扭振故障的轧制力矩基础上,分析了引起轧钢机主传动系统扭振的原因;设计了扭振监测、诊断和控制系统,该系统应用在钢铁企业中取得了令人满意的效果。     

基于Hilbert变换的轴系扭振信号分析

扭转振动是轴系常见的振动形式之一,扭转振动将引起轴系材料的疲劳积累,最终导致轴系破损事故,所以扭振的测量非常重要.应用高精度光电编码器测取扭振信号,当扭振发生时,编码器输出的脉冲信号产生疏密变化,扭振信号对编码器输出的脉冲信号进行频率调制.用希尔伯特变换对调制信号进行解调,直观地得到了整个扭振信号的角位移与角速度波形.对调制信号进行了频谱分析,得出扭振频率与激励信号的频率相一致.研究结果为以后将轴系扭振信号用于回转系统状态监测与故障诊断提供了依据.     

基于粒子群优化五阶段S曲线加减速控制算法

针对同步带传动印刷机启动中的扭振问题,建立了传动带系统的数学模型,通过分析模型找出引起扭振的主要原因,且搭建同步带传动试验平台对扭振现象进行研究.采用五阶段S曲线加减速方法对电机启动输入信号进行规划来抑制系统扭振,并提出运用粒子群优化算法,解决了规划五阶段S曲线参数选取困难的问题.通过仿真试验和试验平台验证可行性,证明了优化后的五阶段S曲线输入信号避开了谐振频率,在较小的牺牲同步带系统动态性能的同时大幅度抑制扭振.     

转子动态过程弯扭耦合振动的仿真和实验

利用弯扭耦合振动微分方程,仿真研究了弯曲振动与扭转振动的相互影响。研究结 果表明,轴系上的不平衡使得弯曲振动和扭转振动之间产生耦合,导致轴系上发生扭转振动。 当轴系上发生扭矩冲击时,将发生频率为固有频率的扭转振动,弯振的振幅稍有增大。实验 研究证实了仿真研究的结果。仿真研究表明,当轴系转速在弯扭耦合区而没有发生弯扭耦合 时,扭矩冲击可能会导致转子发生较大的弯曲振动和扭转振动。     

Bending-Torsional Coupled Vibration Test of Large Power Gear Transmission System

In order to test the bending-torsional coupled vibration characteristics of the multi-shafts gear transmission system of large power vehicles, a torsional vibration exciter was used to apply torsional excitation on the gear transmission systems and thirty-two acceleration sensors were used to measure the tangential acceleration of each shaft. Torsional vibration signals and bending vibration signals of each measuring point were obtained by calculation of the four-point-response signal. The modal parameters of gear transmission systems including nature frequency, modal shape and modal damping ratio were obtained by identifying modal parameters of the torsional vibration signal and bending vibration signal. The characteristic of the bending vibration and torsional vibration of the gear systems were studied through the analysis of the nature frequency and modal shape. The nonlinearity characteristic of the gear transmission system was investigated through single frequency excitation test, which can be the foundation for further nonlinearity research.     

Nonlinear dynamic behavior of rubbing rotor under interaction between bending and torsional vibrations

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Torsional vibration analysis of lathe spindle system with unbalanced workpiece

For the purpose of analyzing the torsional vibration caused by the gravitational unbalance torque arisen in a spindle system when it is machining heavy work piece, a 10-DOF lumped parameter model was made for the machine tool spindle system with geared transmission. By using the elementary method and Runge-Kutta method in Matlab, the eigenvalue problem was solved and the pure torsional vibration responses were obtained and examined. The results show that the spindle system cannot operate in the desired constant rotating speed as far as the gravitational unbalance torque is engaged, so it may cause bad effect on machining accuracy. And the torsional vibration increases infinitely near the resonant frequencies, so the spindle system cannot operate normally during these spindle speed ranges.     

Self-excited vibration of driveline for vehicle launch

The launch shudder phenomenon induced by self-excited vibration of driveline was studied with a compact car equipped with AMT as research object. The research showed that self-excited vibration was closely related with damping of driveline,the variation of friction coefficient,equivalent radius of friction plate and applied force of pressure plate. Six DOFs torsional vibration model of vehicle driveline was established according to the parameters of the certain compact car. The simulation was carried out and the result was compared with test data. It was found that the negative slope of friction coefficient with relative slip speed does not necessarily lead to self-excited vibration and the frequency of self-excited vibration on 1 st gear is near to the 1 st order of torsional natural frequency.The influence of each viscous damping in driveline on self-excited vibration was analyzed by simulation and the results showed that increasing the torsional dampings of half-axles and tires properly was effective to improve launch shudder phenomenon.     

汽车传动系扭振阻尼的一种试验识别方法

汽车传动系扭振阻尼的确定是目前汽车动力传动系扭振研究中所面临的困难的课题之一。本文提出了一种采用整车自由衰减振动试验和模态分析理论识别传动系扭振阻尼及驱动轮胎扭振等效粘性阻尼的方法。叙述了试验方法和分析原理,指出了这种阻尼测试方法进一步发展的途径。     

Finite Element Modeling and Vibration Analysis of Sprag Clutch-Flexible Rotor System

斜撑离合器-柔性转子系统有限元建模及振动特性分析

黄创^1,2,赵永强^1*,靳广虎^3*

（1. 哈尔滨工业大学 机电工程学院,哈尔滨 150001;

2. 珠海格力电器股份有限公司,广东 珠海 519070;

3. 南京航空航天大学 直升机传动技术重点实验室,南京 210016）

摘要：

为研究高速运行工况下斜撑离合器-柔性转子系统 (SC-FRS,sprag clutch-flexible rotor system) 的整体振动特性,基于推导的斜撑离合器刚度矩阵的计算方法,建立了考虑转子柔性及轴承支撑刚度的SC-FRS的有限元模型。以此模型为基础,计算了系统的固有频率和模态振型,通过与ANSYS软件计算结果的比较,验证了本文模型正确性。同时,在不平衡量作用下,分析了系统的弯扭耦合振动和中介轴承动载荷,研究发现扭转方向的共振峰与弯曲方向的共振峰有着相同的共振频率。搭建了斜撑离合器-转子系统试验台,进行了轴心轨迹和临界转速的测试,试验结果表明使用SC-FRS的有限元模型能够较准确地描述系统的振动特性。

关键词：斜撑离合器转子系统;有限元模型;不平衡量;实验验证

     

Research on the Critical Speed of a Mixed-Flow Turbocharger with Hybrid Ceramic Ball Bearing

The critical speeds for a vehicle turbocharger with hybrid ceramic ball bearing are researched. The ball bearing-rotor system produces resonance when it working in critical speed and that makes the turbocharger injury working for a long time. The calculation and analysis methods of the critical speed for the vehicle turbocharger are described. The critical speed is computed by two methods including Riccati transfer matrix and DyRoBeS finite element method for a vehicle turbocharger with hybrid ceramic ball bearing. The vibration experiment had been taken to validate the calculating result. Comparison between the results by two calculation methods and the test results show that the first critical speed differences are 6.47% and 5.66%, the second critical speed differences are 2.87% and 2.94% respectively. And then, the primary factors which influence the critical speed are analyzed, the conclusions will be helpful for the vehicle turbocharger bearing-rotor system design.     

A new hybrid piezoelectric ultrasonic motor with two stators

A new hybrid piezoelectric ultrasonic motor, which consists of one rotor and two stators, was proposed in this paper. In order to match the resonance frequencies of longitudinal vibration and torsional vibration excited in the stators, a symmetrical structure was adopted in design of the motor. A so-called mass matching method, namely adding two rings to the outside circumference of the two stators respectively, was used to adjust the resonance frequencies of these two vibrations. A finite element model was developed using ANSYS software for the purpose of analyzing the resonance frequencies of longitudinal vibration and torsional vibration as well as the function of the adjusting rings. The results show that the resonance frequency of torsional vibration varies with the position of the ring, but the resonance frequency of longitudinal vibration changes little. By means of adjusting the mass and the position of the rings, the first order resonance frequency of longitudinal vibration is coincided with that of torsional vibration and the value is 20.75kHz. An experimental prototype motor was fabricated according to the analytical results and its performance is in agreement with the theoretical predictions. The speed of motor reaches the maximum 92r/min at the working frequency 19.0kHz.