Novel Approach to Rotorcraft Simulation Fidelity Enhancement and Assessment
Lead Research Organisation:
CRANFIELD UNIVERSITY
Department Name: Sch of Aerospace, Transport & Manufact
Abstract
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Publications
Agarwal D
(2021)
Rotorcraft Lateral-Directional Oscillations: The Anatomy of a Nuisance Mode
in Journal of the American Helicopter Society
Agarwal D
(2022)
The use of augmented rotor inflow to predict rotorcraft responses in hover and low-speed manoeuvres
in The Aeronautical Journal
Lu, L.
(2022)
A new heuristic approach to rotorcraft system identification
in Journal of American Helicopter Society
Memon W
(2021)
Helicopter Handling Qualities: A study in pilot control compensation
in The Aeronautical Journal
White M
(2021)
Review of flight simulation fidelity requirements to help reduce 'rotorcraft loss of control in-flight' accident rates
in CEAS Aeronautical Journal
| Description | Our team used a computer simulation model called FLIGHTLAB Bell 412, along with real-world flight measurements, to investigate how accurate the simulation was in predicting certain types of movement during flight. Specifically, we focused on something called lateral-directional oscillation (LDO) and compared the simulation's predictions to what we observed in real flight tests. To improve the accuracy of the simulation model, we made some changes to it. After that, we compared the simulation's predictions to the results from the real flight tests. We found that for certain aspects of LDO movement, the simulation was very good at predicting what would happen in real life. However, for other aspects of LDO movement, the simulation wasn't as accurate. To better understand the reasons behind these differences, we came up with a new way of analyzing the simulation. Instead of looking at the simulation as a whole, we broke it down into smaller parts and analyzed each part separately. By doing this, we were able to identify which parts of the simulation were affecting its overall accuracy the most. Overall, our findings showed that the simulation was generally good at predicting certain types of movement, but it wasn't as good at predicting lateral-directional oscillation. Our new analysis method helped us identify specific areas where the simulation could be improved. We also discovered a new way of analyzing the simulation that can help identify potential issues with its accuracy. |
| Exploitation Route | Vertical Aerospace, a newly established UK startup company, has reached out to us regarding their newly developed X4 aircraft. They intend to apply a new heuristic approach to better comprehend the flight dynamics of the aircraft. |
| Sectors | Aerospace, Defence and Marine,Digital/Communication/Information Technologies (including Software),Education |
| Description | The innovative UK startup, Vertical Aerospace, has recently reached out to our organization with a request to apply a cutting-edge heuristic approach. This approach aims to provide a deeper understanding of the complex flight dynamics associated with their state-of-the-art X4 aircraft. In addition to Vertical Aerospace, we have also had the pleasure of collaborating with the esteemed Italian helicopter company, Leonardo. Our organization's developed derivative breakdown methodology was utilized by Leonardo to conduct a thorough analysis of physical sources of deficiencies associated with one of their models. |
| First Year Of Impact | 2022 |
| Sector | Aerospace, Defence and Marine,Digital/Communication/Information Technologies (including Software) |
| Impact Types | Economic |
| Title | A New Heuristic Approach to Rotorcraft System Identification |
| Description | The new approach identifies the parameters of the flight model in an additive manner, based on their contribution to the local dynamic response of the system. This is in contrast to conventional approaches where parameter values are identified to minimize errors over an entire manoeuvre. In these early investigations, low-order rigid-body linear models have been identified and show good agreement with flight test data. The approach is extended to explore nonlinearities attributed to manoeuvre wake distortion and skew effects that emerge during larger manoeuvres. |
| Type Of Material | Improvements to research infrastructure |
| Year Produced | 2022 |
| Provided To Others? | Yes |
| Impact | The research presents a robust tool for the academic community to conduct system identification based on physical information. It not only facilitates the capture of the physical system with a high degree of fidelity but also engenders the design of a control system with superior performance. In addition, the industry can leverage this innovative tool to reliably assess the trim, stability, and responses of a novel model and discern the outcomes from a physical standpoint. The tool is particularly salient in illuminating the intricacies arising from aerodynamic couplings and interference effects. Furthermore, the information derived from this approach can be utilized to prepare a model and enhance its fidelity, thereby serving as a potent mechanism for training and certification. |
| URL | https://doi.org/10.4050/JAHS.68.022005 |
| Title | Helicopter handling qualities: a study in pilot control compensation |
| Description | This study presents a novel metric that utilizes time-varying frequency-domain exposure to investigate the relationship between a pilot's subjective assessment, measured control activity, and task performance. By combining results from subjective and objective metrics for a range of mission task elements, compensation boundaries are proposed to predict and verify subjective assessments obtained using the Cooper-Harper Handling Qualities Rating scale. |
| Type Of Material | Improvements to research infrastructure |
| Year Produced | 2022 |
| Provided To Others? | Yes |
| Impact | These findings contribute to a deeper understanding of the complex interplay between pilot perceptions, control activity, and task performance, and have implications for the design and evaluation of aircraft systems. |
| URL | https://doi.org/10.1017/aer.2021.87 |
| Title | Rotorcraft Lateral-Directional Oscillations: The Anatomy of a Nuisance Mode |
| Description | High fidelity rotorcraft flight simulation relies on the availability of a quality flight model that further demands a good level of understanding of the complexities arising from aerodynamic couplings and interference effects. One such example is the difficulty in prediction of the characteristics of the rotorcraft lateral-directional oscillation (LDO) mode in simulation. Achieving an acceptable level of the damping of this mode is a design challenge requiring simulation models with sufficient fidelity that reveal sources of destabilizing effects. This method is focused on using System Identification to highlight such fidelity issues using Liverpool's FLIGHTLAB Bell 412 simulation model and in-flight LDO measurements from the National Research Council's (Canada) Advanced Systems Research Aircraft. The simulation model was renovated to improve the fidelity of the model. |
| Type Of Material | Technology assay or reagent |
| Year Produced | 2020 |
| Provided To Others? | No |
| Impact | The results show a close match between the identified models and flight test for the LDO mode frequency and damping. Comparison of identified stability and control derivatives with those predicted by the simulation model highlight areas of good and poor fidelity. |
| Title | FT2 |
| Description | Bell412 blade state measurements from flight test |
| Type Of Material | Data analysis technique |
| Year Produced | 2022 |
| Provided To Others? | Yes |
| Impact | help to build a high fidelity rotor blade model. |
| Description | Collaboration with National Research Council of Canada |
| Organisation | National Research Council of Canada |
| Department | Aerodynamics Laboratory |
| Country | Canada |
| Sector | Public |
| PI Contribution | not suitable |
| Collaborator Contribution | National Research Council of Canada's provides their Bell 412 Advanced Systems Research Aircraft for conducting flight test for the awarded research. These flight test data are one of factors guaranteeing the successful delivery of this project. |
| Impact | So far we conducted the 1st flight test in October 2018 on the Bell 412 helicopter and the 2nd flight test has been scheduled and will occur June 2019. |
| Start Year | 2018 |
| Description | EASA |
| Organisation | European Aviation Safety Agency |
| Country | Germany |
| Sector | Public |
| PI Contribution | We work together to generate the guideline in support of certification is expected to commence well in advance of the certification campaign, and ideally should grow with the development of the different prototypes of a new aircraft in order to program well in advance the tests required to validate the FSM and include these in the development plans of a new aircraft. We applied the knowledge and skills from the EPSRC funded project to enhance this collaboration. |
| Collaborator Contribution | EASA provided the necessary guidance and supports from the regulator's point of view. |
| Impact | We are working together to generate the guideline in support of certification is expected to commence well in advance of the certification campaign, and ideally should grow with the development of the different prototypes of a new aircraft in order to program well in advance the tests required to validate the FSM and include these in the development plans of a new aircraft. We applied the knowledge and skills from the EPSRC funded project to enhance this collaboration. This guideline will be issued by EASA soon, possibly in the middle of this year. |
| Start Year | 2020 |
| Description | leonardo helicopters |
| Organisation | Leonardo S.p.A. |
| Country | Italy |
| Sector | Private |
| PI Contribution | We will use the methodology developed in the EPSRC funded RSF project to improve the AW109 FLIGHTLAB model provided by Leonardo S.p.A. |
| Collaborator Contribution | Leonardo S.p.A. will provide AW109 FLIGHTLAB model and full sets of flight data for usage. |
| Impact | not yet |
| Start Year | 2019 |
| Title | ASID |
| Description | The new approach identifies flight model parameters 'additively', based on their contribution to the local dynamic response of the system, in contrast with conventional approaches where parameter values are identified to minimize errors over a whole manoeuvre. In these early investigations, identified low-order rigid-body linear models show good comparison with flight test data. The approach is extended to explore nonlinearities attributed to so-called manoeuvre wake distortion and skew effects emerging in larger manoeuvres. |
| Type Of Technology | New/Improved Technique/Technology |
| Year Produced | 2022 |
| Impact | The research provides a powerful tool for academia to conduct system identification based on physical information. This not only can capture the physical system at a high level of fidelity but also lead to the design of a control system with better performance. The industry can use this new tool to reliably access the trim, stability, and responses of a new model and interpret the results from the physical point of view. It can lead to a good level of understanding of the complexities arising from aerodynamic couplings and interference effects Moreover, the information extracted from this approach can be used to prepare a model and improve its fidelity to serve the purpose of training and certification. |
| URL | https://doi.org/10.4050/JAHS.68.022005 |
| Description | ERtalk 2021 |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Around 100 international academic and senior industrial players attended my talk on using simulation for certification. I presented a system identification based approach to improve the fidelity of a simulation model. The aududices showed great interest and triggered quite a few questions. |
| Year(s) Of Engagement Activity | 2021 |
| URL | https://www.youtube.com/watch?v=OO3wU-bB7kw&t=497s |
| Description | MSc System Identificaiton Module |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Postgraduate students |
| Results and Impact | 27 postgraduate students attended the Introduction on System Identification. The lectures triggered a lot of interesting questions and discussions in this field. A few students commented that they will use this technique in some industrial areas such as verification and validation of the quality of an aircraft. |
| Year(s) Of Engagement Activity | 2021,2022 |
| Description | Rotorcraft Certification by Simulation-Technical general meeting |
| Form Of Engagement Activity | A formal working group, expert panel or dialogue |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Industry/Business |
| Results and Impact | The workshop was attended by approximately 40 participants from major institutes, universities, and industries around the world, including key players such as Volocopter, Vertical Aerospace, Leonard Helicopter, Airbus, EASA, and FAA, among others. This gathering served as a catalyst for promoting the use of high-fidelity simulation environments for certification purposes. The insights and knowledge gained from the workshop are expected to pave the way for a more efficient and cost-effective approach to certifying new aircraft types, thus benefiting the aviation industry as a whole. Furthermore, the willingness of Volocopter to share its flight test data and aircraft models with an academic institute marks a significant step towards more collaboration between industry and academia, which could lead to more breakthroughs in EVTOL technology. |
| Year(s) Of Engagement Activity | 2022 |