飞机地面牵引载荷分析与控制技术研究

Due to the result from bad operating situations, emergencies or human errors, it is usually inevitable that larger towing loads would be produced when the aircraft towed. Once the loads exceed the load limit of aircraft or other equipment’s components, it may cause an accident. Against this background, our project will conduct the study of analyzing and controlling the towing loads and its consequence. The main contents are as following: Firstly, we will model the “aircraft-towbar-tractor” system with driver in detail, and by test, develop accurate mathematical description of the important component’s nonlinear characteristics and dynamic towing process. Secondly, we will extensively research the influences on towing loads from the factors such as the weight matching between aircraft and tractor, the suspension characteristics, starting and braking performance, towing situation, towing path, response capability and behavior of the driver, etc. As a result, we could provide some quantized references for revision of relevant regulation in future. Finally, in order to improve the present situation that towing loads are uncontrollable and consequently safety can not been maintained when in special conditions or under non-normal operation, this project will propose and develop a new type towbar with controllable shock absorption, which could change its own stiffness and damping in real-time. Appropriate multi-objective optimization adaptive control law will be studied. The control effects of the new type towbar will be evaluated by means of tests and simulations.

飞机地面牵引过程中，由于作业环境、突发事件或人的因素，不可避免会产生较大的牵引载荷，一旦超出飞机或其他设备相关部件的载荷限制，就可能造成事故。本项目以此为背景，进行飞机地面牵引过程有关牵引载荷及其影响的分析与控制研究，内容包括：1) 建立精细、可信的含“驾驶员”环节的“飞机－牵引杆－牵引车”系统动力学模型，借助试验对系统各重要结构的非线性特性、牵引动态过程进行准确描述。2) 较全面地研究包括“飞机－牵引车”重量匹配，牵引车悬架、启动和制动特性，牵引作业环境、路径以及“驾驶员”的工作反应、行为模式等因素对地面牵引载荷的影响，可以为相关规范的制订提供量化参考。3) 现行牵引作业中牵引载荷无法控制，遇到特殊情况或非正常作业时无法保证安全，本项目提出并研制一种新型可控缓冲特性牵引杆，可根据需要实时改变自身刚度和阻尼；研究适用的多目标优化自适应控制律，通过仿真和试验对其牵引载荷控制效果进行评估。

飞机在地面牵引过程中，由于天气、环境、突发意外事件、人为失误等因素可能会造成人员伤亡或财产损失的地面事故。这些事故虽不像空难事故那样损失惨重、影响巨大，但其发生频率之高，因此同样应该引起足够的警惕和重视。有鉴于此，本文针对航空地面安全，研究探讨地面牵引过程的安全问题。主要研究内容包括：.1）基于Adams仿真平台，针对B737-800飞机建立了飞机牵引系统的动力学仿真模型，考虑了实际牵引系统存在的连接间隙引起的接触碰撞，对牵引飞机经过地面凹坑和凸起此类不平坦路面产生的牵引载荷及起落架部件受载进行了仿真分析，并考察了不同牵引速度产生的影响；对不同刹车制动力对牵引载荷的影响进行了分析。讨论了不匹配牵引系统对载荷的影响，分析了B737-800型飞机前起落架下阻力臂在牵引载荷作用下的失效型式。.2）针对现行牵引作业中牵引载荷无法控制，遇到特殊情况或非正常作业时无法保证安全的问题，本文提出对牵引载荷实施控制以提高牵引作业安全性的思想并设计了一种新型牵引杆，基于主动式和被动式两类控制方法，该牵引杆可根据需要实时改变自身刚度和阻尼。对确定缓冲参数进行了研究，建立了相关数学模型，通过仿真对可控缓冲特性牵引杆的应用效果进行评估。.3）研制了基于溢流阀的被动式液压缓冲牵引杆，并进行了车辆地面牵引试验。试验结果表明该牵引杆可以有效减少地面牵引载荷，具有较高的实际应用价值和可行性。