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Browsing Staff publications (AIRS) by Subject "4001 Aerospace Engineering"

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    A comparative analysis of hybrid sensor fusion schemes for visual–inertial navigation
    (Institute of Electrical and Electronics Engineers (IEEE), 2025-12-31) Tabassum, Tarafder Elmi; Petrunin, Ivan; Rana, Zeeshan A.
    Visual Inertial Odometry (VIO) has been extensively studied for navigation in GNSS-denied environments, but its performance can be heavily impacted by the complexity of the navigation environments such as weather conditions, illumination variation, flight dynamics, and environmental structure. Hybrid fusion approaches integrating Neural Networks (NN), especially Gated Recurrent units (GRU) with the Kalman filters (KF), such as Error-State Kalman Filter (ESKF) have shown promising results mitigating system nonlinearities due to challenging environmental conditions data issues, there is a lack of systematic studies quantitively analysing and comparing performance differences unhand. To address this gap and enable robust navigation in complex conditions, this study proposes and systematically analyses the performance of three hybrid fusion schemes for VIO-based navigation of Unmanned Aerial Vehicles (UAV). These three hybrid VIO schemes include Visual Odometry (VO) error compensation using NN, KF error compensation using NN, and prediction of Kalman gain using NN. The comparative analysis is performed using data generated in MATLAB incorporating the Unreal Engine involving diverse challenging environmental conditions: fog, rain, illumination level variability and variability in the number of features available for extraction during the UAV flight in the urban environment. The results demonstrate the performance improvement achieved by hybrid VIO fusion schemes compared to ESKF-based traditional fusion methods in the presence of multiple visual failure modes. Comparative analysis reveals notable improvement achieved by method 1 with enhancements of 93% in sunny, 91% in foggy and 90% in rainy conditions than the other two hybrid VIO architectures.
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    Damping identification sensitivity in flutter speed estimation
    (MDPI , 2025-06-01) Dessena, Gabriele; Pontillo, Alessandro; Civera, Marco; Ignatyev, Dmitry I.; Whidborne, James F.; Zanotti Fragonara, Luca
    Predicting flutter remains a key challenge in aeroelastic research, with certain models relying on modal parameters, such as natural frequencies and damping ratios. These models are particularly useful in early design stages or for the development of small Unmanned Aerial Vehicles (maximum take-off mass below 7 kg). This study evaluates two frequency-domain system identification methods, Fast Relaxed Vector Fitting (FRVF) and the Loewner Framework (LF), for predicting the flutter onset speed of a flexible wing model. Both methods are applied to extract modal parameters from Ground Vibration Testing data, which are subsequently used to develop a reduced-order model with two degrees of freedom. The results indicate that FRVF- and LF-informed models provide reliable flutter speed, with predictions deviating by no more than 3% (FRVF) and 5% (LF) from the N4SID-informed benchmark. The findings highlight the sensitivity of flutter speed predictions to damping ratio identification accuracy and demonstrate the potential of these methods as computationally efficient alternatives for preliminary aeroelastic assessments.
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    On the application of trapped vortices in motorsport application for improved aerodynamic performance using passive and active flow controls
    (SAE International, 2025-04-15) Ng, Ming Kin; Teschner, Tom-Robin
    New regulations introduced by the FĂ©dĂ©ration Internationale de l’Automobile (FIA) for the 2026 Formula 1 season mark the first instance of active flow control methods being endorsed in Formula 1 competition. While active methods have demonstrated significant success in airfoil development, their broader application to grounded vehicle aerodynamics remains unexplored. This research investigates the effectiveness of trapped vortex cavity (TVC) technology in both active and passive flow controls, applied to a NACA0012 airfoil and an inverted three-element airfoil from a Formula 1 model. The investigation is conducted using numerical methods to evaluate the aerodynamic performance and potential of TVC in this paper. In the single-airfoil case, a circular cavity is placed along the trailing edge (TE) on the suction surface; for the three-element airfoils, the cavity is positioned on each airfoil to determine the optimum location. The results show that the presence of a cavity, particularly with active flow control, significantly improves the lift-to-drag ratio (CL/CD) for both the single airfoil and the three-element airfoils. A maximum enhancement of 1160% was recorded for the single airfoil, while the three-element airfoils saw an improvement of 313% compared to their original configurations. However, when the TVC was placed in positions other than the TE of the mid-airfoil, a performance reduction was observed, even with active blowing applied. The passive flow control approach, which requires no additional energy input, yielded a modest improvement of 3.52% for the NACA0012 airfoil. However, passive control underperformed due to unstable vortex interactions with each airfoil element for the inverted three-element airfoil case. Even with optimal placement and geometrical modifications, the maximum CL/CD ratio for passive control was only 96% of the original CL/CD of the unmodified three-element airfoils, suggesting that passive flow control is less effective here compared to active flow control.