Novel Approach to Rotorcraft Simulation Fidelity Enhancement and Assessment

The vision for this research is to develop a novel toolset for flight simulation fidelity enhancement. This represents a step-change in simulator qualification, is well-timed making a significant contribution to the UoL initiated NATO STO AVT-296-RTG activity and will have an immediate impact through engagement with Industry partners.

High fidelity modelling and simulation are prerequisites for ensuring confidence in decision making during aircraft design and development, including performance and handling qualities estimation, control law development, aircraft dynamic loads analysis, and the creation of a realistic piloted simulation environment. The ability to evaluate/optimise concepts with high confidence and stimulate realistic pilot behaviour are the kernels of quality flight simulation, in which pilots can train to operate aircraft proficiently and safely and industry can design with lower risk.
Regulatory standards such as CS-FSTD(H) and FAA AC120-63 describe the certification criteria and procedures for rotorcraft flight training simulators. These documents detail the component fidelity required to achieve "fitness for purpose", with criteria based on "tolerances", defined as acceptable differences between simulation and flight, typically +/- 10% for the flight model. However, these have not been updated for several decades, while on the military side, the related practices in NATO nations are not harmonised and have often been developed for specific applications. Methods to update the models for improved fidelity are mostly ad-hoc and, without a strong scientific foundation, are often not physics-based.

This research will provide a framework for such harmonisation removing the barriers to adopting physics-based flight modelling and will create new, more informed, standards. In this research two aspects of fidelity will be tackled, predictive fidelity (the metrics and tolerances in the standards) and perceptual fidelity (pilot opinion). The predictive fidelity aspect of the research will use System Identification techniques to provide a systematic framework for 'enhancing' a physics-based simulation model. The perceptual fidelity research will develop a rational, novel process for task-specific motion tuning together with a robust methodology for capturing pilots' subjective assessment of the overall fidelity of a simulator. Extensive use will be made of flight simulation and real-world flight tests throughout this project in both the predictive and perceptual fidelity research.

There will be many beneficiaries from this work including Universities, the simulation industry and research institutes.

In terms of the rotorcraft simulation industry, an immediate impact will be made via one of the project partners, Advanced Rotorcraft Technology (ART) who will use the outputs from the research to upgrade their FLIGHTLAB software. Other beneficiaries will be the wider rotorcraft simulation industry who will improve the quality and competitiveness of their products, through engagement with regular webinars and workshops. The outputs of the research will provide a stronger scientific basis for fidelity. It will also enable the adoption of improved certification metrics and tests in new standards. This pathway will lead to deeper industry and regulator understanding and the subsequent adoption of the proposed processes and practices in their operations. The methodology developed in the will provide the basis for model enhancement and informing future defence requirements for training devices and their certification, feeding into future aircraft clearance activities.

A problem-based-learning (PBL) workshop will be developed and held at the University of Liverpool. The workshop will involve rotorcraft simulation model development and validation, real time simulation and fidelity assessment by test pilots and will attract significant interest from the rotorcraft and flight simulator industries, together with test pilot/engineer schools and civil and military regulatory authorities and academia e.g. UK's Vertical Lift Network (VLN). The material from this activity will form the basis of a workshop that can be delivered at international conferences e.g. European Rotorcraft Fora (ERF) to ensure the knowledge and understanding gained from the project are made available to the broader rotorcraft community. Further dissemination of the research outputs will occur through conference (e.g. American Helicopter Society (AHS) Forum, ERF) and journal publications (e.g. Aeronautical Journal, Progress in Aerospace Sciences).

Academia will benefit from the research at both the collaborating Universities and at other institutions. The PBL workshop will be open to academia and the project will make accessible a large amount of flight and simulation data to other institutions for their own research needs, leading to new research opportunities. Outputs from the proposed research will be woven into the curricula and module specifications at both the institutes collaborating in the project.

The proposed research will contribute to the NATO STO AVT-296-RTG activity, "Rotorcraft Flight Simulation Model Fidelity Improvement and Assessment", (2018-20) and the follow-on research lecture series. The research lecture series, to be given in three NATO nations, is another key pathway to impact, delivering knowledge and best practices to industry, government and academia.

Schools will also be potential beneficiaries of the research as a programme of visits to school and school visits to the simulator will be developed showcasing the research.