【作者】 姚远；

【导师】 金鼎昌； 张红军；

【作者基本信息】 西南交通大学 ， 车辆工程， 2010， 博士

【摘要】 目前我国重载列车的牵引吨位已达2万吨,随着9600 kW大功率机车投入使用,当轨道表面黏着条件较差,以及在曲线通过时牵引黏着力降低的条件下,机车牵引功率的充分发挥,受到轮轨间有效黏着利用的限制。黏着不足时轮对会产生刚性滑动现象,轮轨间的黏滑振动状态将影响机车黏着牵引,并产生复杂的动力学问题。研究轮轨黏着利用极限态时机车的动态性能,揭示黏着极限态机车的典型振动机理,合理匹配转向架参数,使机车充分发挥轮轨黏着性能并有效地改善驱动系统动态作用力。对铁路机车重载牵引具有理论意义和工程应用价值。本文的主要工作如下：(1)为了更好地表达机车打滑的物理过程,提出滑动率概念,通过引入摩擦系数的温度影响系数F以及Kalker权重系数K,修正小自旋非线性轮轨切向力计算程序,可得到不同轨面黏着条件时轮轨的黏滑特性曲线,能够体现机车驱动动力学研究中轮轨切向力特点。(2)建立单轮对驱动系统的简化动力学模型,根据平均滑动率和动态滑动率分析了黏着极限条件下轮对的黏滑振动稳定性及黏滑振动过程中轮对纵向振动规律。结果表明轮对黏滑振动稳定性取决于轮轨切向力系数的梯度特性,减小轮轨平均滑动率和动态滑动率是增加黏滑振动稳定性和提高机车恢复黏着能力的最根本途径。黏滑振动时,当轮对纵向振动频率为驱动系统扭转固有频率整数倍时,轮对纵向振动发生共振,并且为2倍时共振振幅最大。(3)研究机车打滑时驱动系统及轮对的自激振动,分析黏滑特性曲线梯度特性对驱动系统振动稳定性以及振动频率的影响。结果表明机车打滑过程中,轮轨黏着负斜率特性将使得系统不稳定,振动能量增加,并且激发出振动系统具有固有振动频率的振动。(4)建立弹性定位单轮对横向稳定性分析模型,考虑轮轨平均滑动率影响,研究了驱动工况下单轮对横向稳定性的基本规律。结果表明由于轮轨黏着的饱和特性,驱动工况下轮轨纵向切向力的增加会引起轮对摇头力矩减小,使得轮对横向稳定性增加,但纵向切向力增加引起横向切向力减小反而对轮对横向稳定性不利。(5)利用多刚体动力学软件SIMPACK和数值仿真软件SIMULINK,以HXDIB型机车为例,建立了机电、控制一体化的机车动力学仿真模型,其中驱动系统模型中考虑了轮轨黏滑特性曲线的负斜率特性、电机机械特性以及电传动控制策略的影响。以同一转向架内各轮对角速度及角加速度差判断轮对的黏着状态,通过计算黏着度利用模糊控制方法对机车实施黏着控制。结果表明,该方法可显著提高机车的黏着利用程度。(6)分析机车黏滑振动稳定性以及黏滑振动时轮对的纵向振动等基本规律。阐明黏滑振动机理并据此对机车驱动系统参数进行优化匹配。增大机车转向架结构参数如一系纵向定位刚度、联轴器扭转刚度、电机吊挂刚度和牵引杆纵向刚度有利于提高机车的黏着性能,并需要合理匹配电机吊挂刚度和轮对的一系纵向定位刚度,避免机车打滑时因轮对纵向共振而降低机车黏着性能。(7)根据建立的机电一体化的机车虚拟样机,并实施黏着控制,使机车工作在轮轨黏着极限工况。结果表明,轮轨处于黏着极限态,轮对的蛇行运动使得左右两侧车轮纵向滑动率容易进入黏滑特性曲线负斜率段,机车驱动系统能够激发具有固有振动频率的振动,并且轮对纵向振动与旋转振动相互耦合。通过比较分析各元部件的振动频率及其相互影响规律,总结避免机车驱动系统引发结构共振的参数匹配原则。更多还原

【Abstract】 With high power locomotives being put into use, the full use of traction power is restricted by the effective utilization of the wheel/rail adhesion. The saturation and negative slope characteristics of adhesion cause locomotive some complex dynamic problems. Important theoretical and engineering applications can be made if the locomotive’s dynamic behaviors under saturated adhesion are understood and the bogie structure parameters can be matched reasonably to improve traction force and to reduce the dynamic force. The main works of this paper are as follows:(1)In order to better express the physical process of the locomotive slip, we put forward the concept of slip rate and modify the W/R tangential force calculation program of Shen and Kalker simplified theory by introducing the temperature influence coefficient F of friction and the Kalker weight coefficient K. The different shapes of the wheel-rail adhesion curves can be obtain and that reflect the driving dynamics study of wheel-rail tangential force characteristics.(2)We use a simplified dynamic model with a single wheelset driving system to illuminate the mechanism and dynamic characteristics of the stick-slip vibration and the longitudinal vibration based on the concepts of mean and dynamic slip rates. The stick-slip vibration is a dynamic process alternating between stick state and slip state. The stability of this process depends on the positive and negative damping of the wheelset adhesion. We performed theoretical analysis on the stick-slip vibration according to the mean and the dynamic slip rate. It shows that decreasing the mean slip rate and the dynamic slip rate will improve the stability of the stick-slip vibration. When the stick-slip vibration occurs, the rotary and the longitudinal vibrations of the wheelset are coupled by the longitudinal tangential force. The longitudinal vibration frequencies of the wheel-set are integral multiples of the natural frequency of the driving system. The largest energy occurs at the frequency twice of the nature frequency.(3)We study the self-excited vibration of locomotive drive system under slip and the effect of negative slop of W/R adhesion on the vibration stability of drive system. The phase trajectory of the torsional vibration was drawn and verified to be a stable limit cycle which signifies self-excited vibration. Frequencies of torsional vibration with different combined operating modes were calculated, showing the vibration frequency is in exact accordance with natural frequency of drive system when the self-excited vibration happens.(4)A simplified dynamic model of single wheel set which average slip rate was taken into consideration was used to study the lateral stability of wheel set under driving mode. The hunting stability was analyzed on different adhesion modes between wheel and rail. The results show that the lateral stability of wheel set under driving is superior to that under coasting. The primary reason for improvement is the decreased yaw torque of the wheel set with gradient decreases of adhesion cure because of saturation.(5)A train system dynamics model integrated with the electromechanical and control system is established to simulate the stick-slip vibration phenomenon under saturated adhesion to verify the theoretical analysis. The model considers the negative slope characteristic of wheel-rail adhesion on large slippage, magnetic saturation and torque mechanical property of the pulling motor. A method of detecting the differences of the biggest and smallest value of different axis angular velocity and acceleration in the same bogie and real time calculating the adhesiveness of wheel-rail to control motor by fuzzy control strategy was put forward. The simulation results show:the adhesion control can make the wheel-rail effective adhesive coefficient maintain peak of adhesion to improve the performance of locomotive traction under different rail surface and running condition. The hunting of wheel-set cause fluctuation of the adhesiveness and their main frequencies are identical.(6)A train system dynamics model integrated with the electromechanical and control system is established to simulate the stick-slip vibration phenomenon under saturated adhesion to verify the theoretical analysis. The simulation result shows that:increasing the longitudinal axle guidance stiffness, the motor suspension stiffness, and the drawbar longitudinal stiffness is beneficial to improve the locomotive adhesion performance and the stability of the stick-slip vibration. When the stick-slip vibration occurs, the main frequencies of the wheelset longitudinal vibration are equal to the motor pitching frequency and its integral multiples. Therefore, it requires to optimization the matching of the motor suspension stiffness and the longitudinal axle guidance stiffness to avoid the longitudinal resonance of the structure.(7)According to the established the virtual prototype locomotive integration of mechanical and electrical and adhesion control model and making the locomotive to worke on saturated adhesion conditions. The results show that the natural vibration frequency of the locomotive can be excitated on the saturated adhesion easily compare to the coast condition. The frequencies of locomotive drive system and their mutual influence are analyzed. We sum up the parameter matching principle of drive system to avoid resonance on the saturated adhesion condition.更多还原