scholarly journals A Full-Envelope Air Data Calibration and Three Dimensional Wind Estimation Method Using Global Output-Error Optimization and Flight-Test Techniques

2012 ◽  
Author(s):  
Brian Taylor
Keyword(s):  
Three Dimensional ◽  
Estimation Method ◽  
Flight Test ◽  
Wind Estimation ◽  
Output Error ◽  
Error Optimization ◽  
Data Calibration

scholarly journals Wind Profile Estimation during Flight Path Reconstruction

2020 ◽  
Vol 70 (3) ◽  
pp. 231-239
Author(s):  
T.K. Nusrath Khadeeja ◽  
Jatinder Singh
Keyword(s):  
High Performance ◽  
Flight Test ◽  
Flight Path ◽  
Flow Angle ◽  
Wind Estimation ◽  
Wind Velocities ◽  
Profile Estimation ◽  
The Impact ◽  
Excellent Tool ◽  
Data Calibration

Accuracy of flow angles measurements becomes crucial as the aircraft approaches higher angle of attack. Flight path reconstruction (FPR) is an excellent tool for air data calibration. An important element of air data calibration is the estimation of wind velocities. The objective of this paper is to evaluate different approaches of wind estimation within the framework of FPR. Flight test data of a high performance aircraft is subjected to FPR and the estimated wind velocities and flow angle trajectories are presented and discussed to demonstrate the impact of wind estimation on aircraft flow angles. Results clearly show that accuracy of reconstructed flow angles improves when time varying wind models are used. The proposed analytical wind model is found to be as effective as augmented parameters in Extended Kalman filter and computationally less intensive.

An acoustic liner design methodology based on a statistical source model

2021 ◽  
pp. 1475472X2110238
Author(s):  
Douglas M Nark ◽  
Michael G Jones
Keyword(s):  
Design Methodology ◽  
Three Dimensional ◽  
Aircraft Engine ◽  
Flight Test ◽  
Source Model ◽  
Practical Implementation ◽  
Source Information ◽  
Fan Noise ◽  
Future Design ◽  
Acoustic Liner

The attenuation of fan tones remains an important aspect of fan noise reduction for high bypass ratio turbofan engines. However, as fan design considerations have evolved, the simultaneous reduction of broadband fan noise levels has gained interest. Advanced manufacturing techniques have also opened new possibilities for the practical implementation of broadband liner concepts. To effectively address these elements, practical acoustic liner design methodologies must provide the capability to efficiently predict the acoustic benefits of novel liner configurations. This paper describes such a methodology to design and evaluate multiple candidate liner configurations using realistic, three dimensional geometries for which minimal source information is available. The development of the design methodology has been guided by a series of studies culminating in the design and flight test of a low drag, broadband inlet liner. The excellent component and system noise benefits obtained in this test demonstrate the effectiveness of the broadband liner design process. They also illustrate the value of the approach in concurrently evaluating multiple liner designs and their application to various locations within the aircraft engine nacelle. Thus, the design methodology may be utilized with increased confidence to investigate novel liner configurations in future design studies.

scholarly journals Practical Endurance Estimation for Minimizing Energy Consumption of Multirotor Unmanned Aerial Vehicles

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2221 ◽  
Author(s):  
Myeong-hwan Hwang ◽  
Hyun-Rok Cha ◽  
Sung Yong Jung
Keyword(s):  
Drag Coefficient ◽  
Unmanned Aerial Vehicles ◽  
Estimation Method ◽  
Flight Test ◽  
Flight Time ◽  
Average Error ◽  
Practical Applications ◽  
Aerial Vehicles ◽  
Vehicle Shape ◽  
Battery Discharge

The practically applicable endurance estimation method for multirotor unmanned aerial vehicles (UAVs) using a battery as a power source is proposed. The method considers both hovering and steady-level flights. The endurance, thrust, efficiency, and battery discharge are determined with generally available data from the manufacturer. The effects of the drag coefficient related to vehicle shape and payload weight are examined at various forward flight speeds. As the drag coefficient increases, the optimum speed at the minimum required power and the maximum endurance are reduced. However, the payload weight causes an opposite effect, and the optimal flying speed increases with an increase in the payload weight. For more practical applications for common users, the value of S × Cd is determined from a preliminary flight test. Given this value, the endurance is numerically estimated and validated with the measured flight time. The proposed method can successfully estimate the flight time with an average error of 2.3%. This method would be useful for designers who plan various missions and select UAVs.

A Scalable Time-Parallel Solution of Periodic Rotor Dynamics in X3D

2021 ◽  
Author(s):  
Mrinalgouda Patil ◽  
Anubhav Datta
Keyword(s):  
Harmonic Balance ◽  
Large Scale ◽  
Structural Model ◽  
Three Dimensional ◽  
Harmonic Balance Method ◽  
Flight Test ◽  
Solution Procedure ◽  
Balance Method ◽  
Computational Time ◽  
Near Resonance

A time-parallel algorithm is developed for large-scale three-dimensional rotor dynamic analysis. A modified harmonic balance method with a scalable skyline solver forms the kernel of this algorithm. The algorithm is equipped with a solution procedure suitable for large-scale structures that have lightly damped modes near resonance. The algorithm is integrated in X3D, implemented on a hybrid shared and distributed memory architecture, and demonstrated on a three-dimensional structural model of a UH-60A-like fully articulated rotor. Flight-test data from UH-60A Airloads Program transition flight C8513 are used for validation. The key conclusion is that the new solver converges to the time marching solution more than 50 times faster and achieves a performance greater than 1 teraFLOPS. The significance of this conclusion is that the principal barrier of computational time for trim solution using high-fidelity three-dimensional structures can be overcome with the scalable harmonic balance method demonstrated in this paper.

Auto-landing guidance for unmanned aerial vehicle with engine flame-out

2019 ◽  
Vol 233 (13) ◽  
pp. 4864-4878 ◽  
Author(s):  
Young-Sam Kim ◽  
Min-Jea Tahk
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Trajectory Generation ◽  
Vertical Plane ◽  
Estimation Method ◽  
Terminal Velocity ◽  
Velocity Estimation ◽  
Total Loss ◽  
Aerial Vehicle ◽  
Loss Of Thrust

Landing is the most dangerous phase of the entire flight phases. If the total loss of thrust occurs during flight, a powered aircraft converts to a glider, which can use kinetic and potential energy only. For this reason, a proper scheme is needed for safe landing in cases of the total loss of thrust. This paper presents three-dimensional unpowered auto-landing guidance based on trajectory generation, expanding the concept of the energy-to-range ratio. We develop the terminal velocity estimation method for a horizontal plane applied to three-dimensional space; this method is based on the previously suggested terminal velocity estimation method for a vertical plane. Then, we show trajectory generation for landing guidance combining vertical with horizontal waypoints. The proposed auto-landing guidance with trajectory generation is evaluated by numerical simulation.

scholarly journals A Self-Adaptive Mean Shift Tree-Segmentation Method Using UAV LiDAR Data

2020 ◽  
Vol 12 (3) ◽  
pp. 515 ◽  
Author(s):  
Wanqian Yan ◽  
Haiyan Guan ◽  
Lin Cao ◽  
Yongtao Yu ◽  
Cheng Li ◽  
...  
Keyword(s):  
Mean Shift ◽  
Three Dimensional ◽  
Estimation Method ◽  
Global Maximum ◽  
Maximum Point ◽  
Individual Tree ◽  
3D Space ◽  
Segmentation Accuracy ◽  
Optimal Kernel ◽  
Self Adaptive

Unmanned aerial vehicles using light detection and ranging (UAV LiDAR) with high spatial resolution have shown great potential in forest applications because they can capture vertical structures of forests. Individual tree segmentation is the foundation of many forest research works and applications. The tradition fixed bandwidth mean shift has been applied to individual tree segmentation and proved to be robust in tree segmentation. However, the fixed bandwidth-based segmentation methods are not suitable for various crown sizes, resulting in omission or commission errors. Therefore, to increase tree-segmentation accuracy, we propose a self-adaptive bandwidth estimation method to estimate the optimal kernel bandwidth automatically without any prior knowledge of crown size. First, from the global maximum point, we divide the three-dimensional (3D) space into a set of angular sectors, for each of which a canopy surface is simulated and the potential tree crown boundaries are identified to estimate average crown width as the kernel bandwidth. Afterwards, we use a mean shift with the automatically estimated kernel bandwidth to extract individual tree points. The method is iteratively implemented within a given area until all trees are segmented. The proposed method was tested on the 7 plots acquired by a Velodyne 16E LiDAR system, including 3 simple plots and 4 complex plots, and 95% and 80% of trees were correctly segmented, respectively. Comparative experiments show that our method contributes to the improvement of both segmentation accuracy and computational efficiency.

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