scholarly journals Semi-empiric noise modeling of a Cargo eVTOL UAV by means of system identification from flight noise measurement data

Author(s):  
Michael Schmähl ◽  
Christian Rieger ◽  
Sebastian Speck ◽  
Mirko Hornung

AbstractThis publication shows the semi-empiric noise modeling of an electric-powered vertical takeoff and landing (eVTOL) unmanned aerial vehicle (UAV) by means of system identification from flight noise measurement data. This work aims to provide noise models with a compact analytical ansatz for horizontal and vertical flight which are suited for integration into a geographical information system. Therefore, flight noise measurement campaigns were conducted and evaluated. An existing noise model ansatz is adapted to the eVTOL UAV under consideration and noise models are computed from the measurement data using the output error method. The resulting models are checked for plausibility by comparing them to technical literature. The horizontal flight noise model is subjected to a correlation analysis and the influence of meteorological effects are examined. To achieve a higher level of accuracy in future noise modelings, an optimization of the microphone positions as well as the flight trajectory is carried out.

Author(s):  
Younsaeng Lee ◽  
Seungjoo Kim ◽  
Jinyoung Suk ◽  
Hueonjoon Koo ◽  
Jongseong Kim

Author(s):  
Patricia Everaere ◽  
Sebastien Konieczny ◽  
Pierre Marquis

We study how belief merging operators can be considered as maximum likelihood estimators, i.e., we assume that there exists a (unknown) true state of the world and that each agent participating in the merging process receives a noisy signal of it, characterized by a noise model. The objective is then to aggregate the agents' belief bases to make the best possible guess about the true state of the world. In this paper, some logical connections between the rationality postulates for belief merging (IC postulates) and simple conditions over the noise model under consideration are exhibited. These results provide a new justification for IC merging postulates. We also provide results for two specific natural noise models: the world swap noise and the atom swap noise, by identifying distance-based merging operators that are maximum likelihood estimators for these two noise models.


2018 ◽  
Vol 152 ◽  
pp. 02023 ◽  
Author(s):  
Yasir Ashraf Abd Rahman ◽  
Mohammad Taghi Hajibeigy ◽  
Abdulkareem Shafiq Mahdi Al-Obaidi ◽  
Kean How Cheah

Modern UAVs available in the market have well-developed to cater to the countless field of application. UAVs have their own limitations in terms of flight range and manoeuvrability. The traditional fixed-wing UAVs can fly for long distance but require runways or wide-open spaces for take-off and landing. On the other hand, the more trending multirotor UAVs are extremely manoeuvrable but cannot be used for long-distance flights because of their slower speeds and relatively higher consumption of energy. This study proposed the implementation of hybrid VTOL UAV which has the manoeuvring advantage of a multirotor UAV while having the ability to travel fast to reach a further distance. The design methodology and fabrication method are discussed extensively which would be followed by a number of flight tests to prove the concept. The proposed UAV would be equipped with quadcopter motors and a horizontal thrust motor for vertical and horizontal flight modes respectively.


Entropy ◽  
2020 ◽  
Vol 22 (6) ◽  
pp. 629 ◽  
Author(s):  
Shiguang Zhang ◽  
Ting Zhou ◽  
Lin Sun ◽  
Wei Wang ◽  
Baofang Chang

Due to the complexity of wind speed, it has been reported that mixed-noise models, constituted by multiple noise distributions, perform better than single-noise models. However, most existing regression models suppose that the noise distribution is single. Therefore, we study the Least square S V R of the Gaussian–Laplacian mixed homoscedastic ( G L M − L S S V R ) and heteroscedastic noise ( G L M H − L S S V R ) for complicated or unknown noise distributions. The ALM technique is used to solve model G L M − L S S V R . G L M − L S S V R is used to predict short-term wind speed with historical data. The prediction results indicate that the presented model is superior to the single-noise model, and has fine performance.


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