Lifting Standards: A Novel Approach to the Development of Fidelity Criteria for Rotorcraft Flight Simulators

一些研究主题的背景将有望设置场景。飞行模拟器已成为制造、培训和研究领域不可或缺的组成部分，其应用正在迅速扩大。然而，尽管现代技术的复杂性和先进性，模拟器本质上是无法提供一个准确的现实表示，主要是由于一方面的飞机及其系统的不完整的数学建模和运动的物理限制和视觉提示的另一方面。在培训方面，制定资格标准的一个重要问题是用于规定设备保真度的标准以及支持这些标准的工程基础。部件的保真度很重要，它可能只是反映了技术水平，但标准还要求对综合系统进行飞行员评估，飞行的典型使命架次涵盖了系统将用于的训练方面。主观意见在这里也很重要，因为它反映了一个有经验的飞行员对现实主义水平的重视。然而，量化整体模拟保真度更加困难，但同样重要，因为可以说，组件或子系统保真度只有通过整体测量联系起来，才能与目的的适用性正确相关。为了提供接受合成训练设备的框架，监管机构已经制定了性能标准沿着相关的训练学分，规定了提示环境（运动、视觉、控制加载系统、音频等）和飞机飞行动力学模型的标准。从历史上看，这些标准是从固定翼模拟器的要求中发展出来的，而且旋翼机模拟逼真度的工程基础是真实的和迫切的需要。这是拟议的研究计划，其目的是弥合飞行员主观意见和正式的度量之间的差距差距的重点。例如，目前验证数学模型的过程涉及开发具有所需精度的物理模型，然后在模拟器中实现模型。验证过程需要严格检查模拟器是否符合规定的公差，然后对预定义的测试机动进行飞行评估。为了完成这一过程，将试验结果与飞行试验数据进行比较，并通过“调整”过程对飞行员发现的差异进行“修正”，在此过程中对模型或模拟器系统进行修改，以提高“真实性”。PI与欧洲工业界合作进行的研究表明，在大多数领域，80%的保真度应该可以通过物理建模实现，剩下的20%需要人工调整，但这对于验收至关重要。虽然调整可能能够纠正特定飞行条件下的问题，但它通常对飞行包线的其他部分产生不利影响。因此，为了达到可接受的性能水平，实施了物理上不现实并且难以从工程角度证明的修改。清楚的是，对模拟器提示环境的设置与飞行员的行为之间的关系的理解有限。调整过程的行业实践通常是商业敏感的，当然不在公共领域。所需要的是一个客观的手段来评估模拟器的整体保真度，以补充感知保真度和预测组件保真度，这是拟议的研究的重点。

Some background to the theme of the research will hopefully set the scene. Flight simulators have become integral to the manufacturing, training and research communities and their utilisation is expanding rapidly. However, despite the sophistication and advancement of modern technology, simulators are inherently incapable of providing an exact representation of reality, due largely to incomplete mathematical modelling of the aircraft and its systems on the one hand and the physical limitations of the motion and visual cueing on the other. In the training context, an important issue in the development of the qualification standards is the criteria used to prescribe the fidelity of devices and the engineering basis underpinning them. Component fidelity, which may simply be a reflection of the state of the art , is important, but the standards also require piloted assessment of the integrated system with typical mission sorties flown covering the training aspects for which the system will be used. Subjective opinion here is important too because it reflects the value that an experienced pilot places on the level of realism. Quantifying overall simulation fidelity is more difficult however, but is equally important because, arguably, component or sub-system fidelity can only be properly related to fitness for purpose if connected by measurement of the whole. To provide a framework for the acceptance of synthetic training devices, regulatory authorities have produced performance standards along with associated training credits, specifying criteria for the cueing environment (motion, visuals, control loading system, audio etc) and the aircraft flight dynamics models. Historically, the standards have grown out of the requirements for fixed-wing simulators and there is a real and urgent need for a substantial engineering basis for rotorcraft simulation fidelity. This is the focus of the proposed research programme, which aims to bridge the gap between pilot subjective opinion and formal metrics. For example, the current process for validating mathematical models involves the development of a physical model with a required accuracy, followed by implementation of the model in the simulator. A validation process then requires a rigorous checking of the simulator against specified tolerances followed by piloted evaluations of predefined test manoeuvres. To complete the process, the results of the tests are compared with flight test data and the discrepancies identified by the pilots are 'corrected' through a 'tuning' process, where modifications are made to the model or simulator systems in order to improve the 'realism'. This tuning process will be placed on a firmer engineering basis in teh proposed research.The PI's research, in collaboration with European Industry, has shown that, in most areas, 80% fidelity should be achievable with physical modelling and the remaining 20% requires artificial tuning, yet is critical for acceptance. While tuning may be able to correct problems in a specific flight condition, it often has an adverse affect in other parts of the flight envelope. Thus, to achieve an acceptable level of performance, modifications are implemented which are not physically realistic and difficult to justify from an engineering standpoint. What is clear is that there is limited understanding of the relationship between the settings of the simulator cueing environment and the behaviour of the pilot. Industry practice for the tuning process is usually commercially sensitive and certainly not in the public domain. What is required is an objective means for assessing the overall fidelity of a simulator, to complement the perceived fidelity and the predicted component fidelity; this is the focus of the proposed research.