Browsing by Author "Millidere, Murat"
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Item Open Access Aerodynamic analysis of Saab 340B aircraft with data fusion implementation(AIAA, 2024-01-04) Sahin, Kadir; Gomec, Fazil; Millidere, Murat; Whidborne, JamesThis paper conducts an aerodynamic analysis of the Saab 340B passenger aircraft, employing AVL and as numerical methods and DATCOM as a collection of engineering methods and empirical data that provide a set of aerodynamic coefficients for assessment. The investigation is focused on examining the longitudinal aerodynamic behavior of aircraft, specifically considering the impacts of flaps and elevators at varying angles of attack. The outcomes from the clean configuration are compared with the results obtained from computational fluid dynamics studies found in existing literature. While the results may not precisely match, they capture the general trends in the behavior of the aircraft. This aligns with the expected outcomes from preliminary methods like AVL and DATCOM. Data fusion techniques are strategically employed to integrate insights from these diverse sources, enhancing the overall accuracy and reliability of the aerodynamic assessment. The research aims to provide a comprehensive understanding of the clean configuration's aerodynamic performance, contributing significantly to the advancement of aviation technology.Item Open Access Analysis of visualization systems in flight simulators(AIAA, 2023-06-08) Barrio, Luis D.; Korek, Wojciech; Millidere, Murat; Whidborne, James F.This paper details an analysis of different visualization systems for use in an academic flight simulator, Future Systems Simulator (FSS). First, an overview of off-the-shelf flight simulators is done, detailing the primary features of flight simulators such as Flight Gear, Prepar3D, X-Plane, and Microsoft Flight Simulator (2020). Then, the current setup of the FSS is presented (which uses FlightGear), followed by the process of introducing X-Plane as a scenery-generation tool. To conduct a comparative analysis between FlightGear and X-Plane visual systems, a total of twelve participants with varying levels of experience were invited to participate in the study. The participants performed flight trials in a simple landing scenario at Heathrow Airport. Additionally, the more complex approach at London City Airport was performed with a group of only four highly experienced participants. Participants then gave their feedback and completed a questionnaire. The data from their attempts were recorded for qualitative and quantitative comparison. The results were analyzed to determine which of the two visual systems could be used in the FSS moving forward.Item Open Access Development of aerodynamic and propulsion models using the iterative equation error method(MDPI, 2023-12-21) Millidere, Murat; Akgül, Ferhat; Leblebicioğlu, Kemal; Whidborne, James F.For developing high-fidelity flight simulations, an accurate and complete representation of the aerodynamic characteristics of the aircraft is necessary. To obtain a realistic aerodynamic database, system identification methods can be used to describe the applied forces and moments acting on the aircraft. This study is based on simulated flight test data from a nonlinear simulation of the F-16 aircraft. It is demonstrated that the complete set of aerodynamic coefficients can be reconstructed from the flight test data. Thrust forces and moments are obtained from ground tests. A practical system identification methodology based on the iterative equation error method to determine the nonlinear aerodynamic and engine thrust models in the absence of engine manufacturer data is developed. The estimated values obtained using the method are compared with the actual parameter values. A mathematical engine model that can be used to estimate the thrust force for any flight condition is also developed. The findings demonstrate that the proposed method yields accurate results. The developed methodology is well-suited for the identification of isolated aerodynamic drag and lift coefficients and the thrust model.Item Open Access An investigation of control allocation methods for the ADMIRE simulation model(AIAA, 2023-06-08) Gulcan, Nilsu; Kurt, Huseyin Burak; Karaman, Atakan; Millidere, MuratThis paper presents a comparative study of various control allocation methods, using ADMIRE as a benchmark simulation model. The Ganged Pseudo-Inverse, Weighted Pseudo-Inverse, Cascaded Generalized-Inverse, Daisy Chain, and Linear Programming approaches are evaluated and compared against each other using open loop and closed loop analysis with Euclidean-Norm. In open-loop analysis, control allocation methods are analyzed for each approach that can produce an admissible solution and be able to attain commanded moments. Then, in closed-loop analysis, control allocation methods are compared using ADMIRE nonlinear simulation model for predefined maneuvers which are defined by multiple points in the flight envelope.Item Open Access Modelling, simulation and verification of the Saab 340B(AIAA, 2023-01-19) Makadia, Jeet; Millidere, Murat; Alam, Mushfiqul; Place, Simon; Whidborne, James F.Flight simulation modelling of an aircraft is required for various purposes including performance analysis, flight control design, and flying qualities analysis. The Saab 340B is a twin turboprop transport aircraft designed to seat 30-36 passengers. A Saab 340B has been modified to operate as a flying laboratory for teaching and research purposes at the Cranfield University, United Kingdom. This paper demonstrates a component build-up approach towards creating a simulation model using the data available from the aircraft manufacturer. This approach has previously proven successful in establishing the fundamental working principles of flight dynamics for a Jetstream J31 aircraft. Empirical estimates of the aerodynamic forces and moments acting on the aircraft are calculated from the aircraft’s geometrical parameters using Engineering Sciences Data Unit (ESDU) data sheets. The contribution of this study is a systematic approach to developing an aerodynamic model using ESDU and comparing the results with the collected flight test data across the entire flight envelope for the aircraft.Item Open Access Performance Analysis of eXogenous Kalman Filter for INS/GNSS Navigation Solutions(Elsevier, 2024-11-22) Alam, Mushfiqul; Whidborne, James F.; Millidere, MuratThere are several methods of fusing data for navigation solutions using Inertial Navigation System (INS) aided by Global Navigation Satellite System (GNSS). The most used solutions are nonlinear observer (NLO) and extended Kalman filter (EKF) of various architectures. EKF based estimation methods guarantees sub-optimal solutions but not stability, on the contrary NLO based estimation guarantees stability but not optimality. These complimentary features of EKF and NLO has been combined to design an eXogenous Kalman filter (XKF) where the estimate from the NLO is used as an exogenous signal to calculate the linearized model of the EKF. The performance of the designed XKF is tested on real flight test data collected using a Slingsby T67C ultra-light aircraft. The results show that during the outage of GNSS, in some cases the divergence of position estimates using XKF is lower compared to EKF and NLO, however no clear benefit is achieved.Item Open Access Real-time motion planning for quadcopter using adaptive spherical expansion and sequential convex optimization(AIAA, 2023-01-19) Karaman, Atakan; Kurt, Huseyin Burak; Millidere, Murat; Alam, MushfiqulThis paper introduces the Adaptive Spherical Expansion and Sequential Convex Programming (ASE-SCP) as a real-time motion planning algorithm. ASE-SCP algorithm is an improved version of the Spherical Expansion and Sequential Convex Programming (SE-SCP) algorithm in terms of computational speed. ASE-SCP is a hybrid real-time motion planning algorithm which combines the advantages of the Adaptive Spherical Expansion, such as approaching the neighborhood of the global optimal path, and the quick convergence ability of the Sequential Convex Programming. The ASE-SCP algorithm first finds a collision-free path using the adaptive spherical expansion approach. After finding a feasible path from the start point to the target point, the feasible path is re-optimized (tuned) using sequential convex optimization to find the suboptimal path. ASE-SCP Algorithm is applied to a quadcopter model to demonstrate its applicability.Item Open Access SAAB 340B aerodynamic model development using binary particle swarm optimization(AIAA, 2024-01-04) Millidere, Murat; Alam, Mushfiqul; Place, Simon; Whidborne, Jameshis paper follows-up previous work on the development of a high-fidelity Saab 340B aerodynamic model using system identification methods. In the prior work, Saab 340B flight tests were carried out using different excitations on the control surfaces. The flight test data was collected at predefined trim points. Thrust forces and moment were obtained using the propeller efficiency map provided by the manufacturer. The equation and output error methods were employed to analyse flight test data to estimate aerodynamic parameters in the time domain. This paper follows-up previous work on the development of a high-fidelity Saab 340B aerodynamic model using system identification methods. In the prior work, Saab 340B flight tests were carried out using different excitations on the control surfaces. The flight test data was collected at predefined trim points. Thrust forces and moment were obtained using the propeller efficiency map provided by the manufacturer. The equation and output error methods were employed to analyse flight test data to estimate aerodynamic parameters in the time domain. The paper extends the work to select independent variables in the equation error method in an optimal way using binary particle swarm to determine the best subset of independent variables. The impact of the hyperparameters of the binary PSO approach such as the transfer function scheme, inertia weight updating strategy, and the value of acceleration coefficients is investigated.Item Open Access Vision-based autonomous UGV detection, tracking, and following for a UAV(AIAA, 2024-01-04) Amil, Fatma G.; Sen, Muhammet; Kurt, Huseyin Burak; Beycimen, Semih; Millidere, MuratThis study proposes a methodology for unmanned ground vehicle (UGV) navigation in off-road environments where GPS signals are not available. The Husky-A200 at Cranfield University, United Kingdom has been used as a UGV in this research project. Due to the limited field of vision of UGVs, a UAV-UGV collaboration approach was adopted. The methodology involves five steps. The first step is divided into three phases: The aerial images of UGV from UAV are generated in the first phase. In the second phase, the UGV is detected and tracked using computer vision techniques. In the third phase, the relative pose (position and heading) between the UAV and UGV is estimated continuously using visual data. In the second step, the UAV maintain a fixed location (position and heading) relative to the UGV. The third step involves capturing aerial images from the UAV‘s mounted camera and transmitting it to the ground station instantly to create a global traversability map that classifies terrain features based on their traversability. In the fourth step, additional sensors such as LiDAR, radar, and IMU are used to refine the global traversability map. In the final step, the UGV navigates automatically using the refined traversability map. This study will focus on the first two steps of the methodology, while subsequent studies will address the remaining steps.