Automatic Control of Formation Flight in the Upwind Field of the a Proceeding Aircraft

航空业在未来必须大幅减少排放。像候鸟一样编队飞行时节省能源的潜力早已为人所知，但仍未得到利用。使用这项技术，飞机可以节省15%-20%的燃料。尾部飞机利用前一架飞机的上风场来减少推力，从而减少燃油消耗。在几次飞行测试中，不同类型的飞机成功地节省了8%-15%的燃料，例如在2013年7月，在长途巡航飞行段使用波音C-17运输机。这些飞行是手动或使用试验性的、相对简单的位置控制系统进行的。在第一个项目阶段，证明了使用运输机进行紧密编队飞行是可能的--后面的飞机减少了10%的燃料。提出了自动操作时进入和保持编队的程序，飞行员证实是可行的。设计了控制系统的结构和设计方法，开发了一种对涡轴变化具有较强鲁棒性的上风场位置寻优控制系统。自动编队飞行可以在飞行模拟器中进行演示。到目前为止，调查仅限于两架相同飞机的编队(同质编队)，飞行稳定，直线水平轨迹，并限于没有失败的飞行。根据到目前为止的看法，可以假设编队飞行可以用于商业飞行操作(假设H1)。预期的效益将证明开发必要的系统和程序所需的努力是合理的(H2)。飞机运营商和飞行员仍然缺乏广泛的接受度。只有编队飞行不仅经济高效，而且安全可靠，才能实现这一目标。为了实现这一点，需要一个包括传感器和显示器的自动编队飞行控制系统，它对参数变化具有健壮性，以及涵盖正常飞行操作和故障的飞行程序(H3)。第二阶段项目的目标是根据工作假设H1至H3阐明如何以及在哪些条件下可以安全、高效和舒适地执行自动编队飞行--包括异质编队--以便用于商业飞行操作。研究将分五个步骤进行：1)程序的定义，2)需求的制定，3)传感器和显示器的概念的发展，4)控制系统的设计，5)在飞行模拟器中对步骤1到4的评估。有了飞行模拟器SEPHIR，它在项目期间得到了增强，这是一个非常适合研究的工具。该项目的结果将是正常和故障情况下一致的操作程序，以及控制系统的健壮概念。在此基础上，集成到未来的飞机上是可能的。

Aviation has to significantly reduce its emissions in the future. The potential of saving power while flying in formation like migratory birds has long been known, but is still unused. Using this technique, airplanes can save 15-20% of fuel. The trailing aircraft uses the upwind field of the preceding aircraft to reduce thrust and thereby fuel consumption. In several flight tests fuel reductions of 8-15% were successfully demonstrated for different types of aircraft for example in July 2013 using Boeing C-17 transport aircraft on long cruise flight segments. Those flights were performed manually or by using an experimental, relatively simple position control system.In the first project phase it was demonstrated, that tight formation flight using transport aircraft is possible - with fuel reductions of 10% for the following aircraft. The procedure for entering and maintaining the formation in automatic operation was proposed and pilots confirmed it to be feasible. The structure of the control system and its design methods were devised, a control system for seeking the optimal position in the upwind field which is robust against vortex-axes variations was developed. The automatic formation flight can be demonstrated in a flight simulator. To date the investigations are confined to formations of two identical aircraft (homogenous formation), flying steady, straight horizontal trajectories, and limited to flights without failures.Based on the perceptions made so far it can be assumed that formation flight can be used in commercial flight operations (Hypothesis H1). The expected benefits will justify the efforts that are needed to develop necessary systems and procedures (H2). A broad acceptance by aircraft operators and pilots is still missing. It can only be achieved if formation flight is not only cost-efficient but also safe and reliable. To achieve this, an automatic formation flight control system including sensors and displays, which is robust against parameter changes, as well as flight procedures that cover normal flight operations and failures are required (H3).The objective of the second project phase is to clarify, based on the working hypotheses H1 to H3, how and under which conditions the automatic formation flight - including heterogeneous formations - can be safely, efficiently, and comfortably performed so that it can be used in commercial flight operation. The research will be carried out in five steps: 1) definition of procedures, 2) formulation of requirements, 3) development of a concept for sensors and display, 4) design of the control system, and 5) evaluation of steps 1 to 4 in the flight simulator. With the flight simulator SEPHIR which was enhanced during the project an eminently suitable tool is available for research. Results of the project will be coherent operation procedures for both normal and failure cases and a robust concept for the control system. Based on that an integration into future aircraft is possible.