波动载荷下滑动电接触摩擦动力学与电流传导机理研究

The phenomenon of contact load fluctuating exists in the process of pantograph slide and contact wire providing electrical power for electric locomotive through sliding electrical contact. This phenomenon influences the friction wear and current-receiving quality of pantograph-catenary system. In some cases it even causes power interruption of electric locomotive. The project will conduct sliding electrical contact experiments under fluctuating contact load with different friction material pairs to study influence of the waveform, amplitude and frequency of fluctuating contact load as well as the sliding velocity and current intensity on sliding electrical contact friction and current-carrying properties of pantograph-catenary system. Then the friction model relating current and friction dynamic model will be established via non-smooth kinetic analysis and microscopic analysis of friction surface. The injury and removal mechanisms of current carrying friction contact surface are studied under fluctuating contact load. In addition, the effects of fluctuating load on the dynamic changes of conductive spots will be researched. Some electrical contact theories such as the contact resistance, the contact surface thermal effects and the electric arcing are used to study the influence of fluctuating load on current conduction. After studying the boundary condition of keeping reliable contact, the condition that occur severe wear and conductivity decreasing, as well as the generating conditions and influencing factors of spark and arc, a failure criterion in contact based on actual operating conditions will be proposed and an electrical contact failure model under fluctuating load will be established. At last, a method will be proposed, which can reduce the friction wear and improve the current receiving stability of pantograph-catenary system.

受电弓滑板与接触网导线通过滑动接触为机车提供电力的过程中，存在接触压力载荷波动现象，使弓网的摩擦磨损和受流质量受到影响，严重时会造成电力机车供电中断。项目针对不同的摩擦副材料配对，进行波动压力载荷下的滑动电接触实验，研究波动压力载荷的波形、幅值、频率以及滑动速度、电流强度对弓网滑动电接触摩擦与载流特性的影响；通过建立电流相关的摩擦力模型，摩擦动力学模型，采用非光滑动力学分析方法，结合摩擦副表面的微观分析，研究载荷波动情况下载流摩擦接触面的损伤与去除机制；研究波动载荷对接触导电斑点动态变化的影响，利用接触电阻、接触面热效应、电弧等电接触理论，研究波动载荷对电流传导的影响；通过对保持可靠接触的临界条件，出现严重磨损和电导率下降的条件因素，电火花和电弧的产生条件和影响因素等研究，结合实际运行工况，提出接触失效判据，并建立波动载荷作用下电接触失效模型。提出弓网减小摩擦磨损，提高受流稳定性的方法。

铁路电力机车受电弓滑板与接触网导线滑动接触导电过程中，因接触压力载荷波动，使弓网的摩擦磨损和受流质量受到影响。为了减小这种影响，通过模拟实际工况实验，对摩擦磨损与载流特性、载流摩擦机理、接触电阻模型、摩擦力模型与力学特性、接触失效及控制与抑制方法等进行了系列研究。获得了弓网摩擦力和磨损率以及载流稳定性与压力波动幅度、波动频率、滑动速度、接触电流之间的特性规律。接触电阻的大小直接影响电流传导，对动态接触电阻进行了时频分析，结合表面形貌分析，得到了接触电阻的特性规律、影响因素和动态变化机理；基于数据驱动模型—ε不敏感支持向量机和极限学习机(ELM)分别建立了弓网滑动接触电阻的预测模型。基于Dieterich-Ruina摩擦定律，建立了载流摩擦系数经验模型；利用速度相关的Stribeck摩擦模型和库伦+黏性静摩擦模型，分别建立与速度、波动接触力和电流相关的弓网载流摩擦力模型，并证明了模型的有效性。由于摩擦力的波动反映了接触状态的变化，用摩擦力波动百分比描述接触状态的优、中、劣特征，通过给定的质量函数，挖掘出高质量的摩擦力学规则模型，进而利用建立的摩擦力学语言规则模型分析了摩擦力动力学特性与压力载荷波动、载流和运行速度之间的影响关系。将接触电阻和电流稳定系数综合考虑提出了弓网滑动电接触失效判据；结合微观实验分析了弓网接触失效机理，在此基础上根据接触电阻概率分布建立了失效概率模型，最后分析给出了一定工况条件下弓网滑动电接触的失效概率。采用不同的建模方法、优化方法、寻优指标研究了各种工况下的最优接触压力载荷确定方法；针对弓网接触非线性时变、未知参数、风载荷干扰等问题提出了压力载荷的反馈线性化控制、滑模控制、自适应控制、LQR控制、模糊控制等控制方法，这些控制方法与波动抑制方法，工程实际考虑充分，各有特点，具有理论意义和实践价值。.全面完成计划任务书所规定的研究内容，共发表或录用学术论文30篇，授权国家发明专利2项，培养研究生17名。