scholarly journals Supplementary material to "Characterization of the Particle Emission from Ships Operating at Sea Using Unmanned Aerial Vehicles"

Author(s):  
Tommaso F. Villa ◽  
Reece Brown ◽  
E. Rohan Jayaratne ◽  
L. Felipe Gonzalez ◽  
Lidia Morawska ◽  
...  
Author(s):  
Portia Banerjee ◽  
Wendy A. Okolo ◽  
Andrew J. Moore

Abstract Owing to the frequency of occurrence and high risk associated with bearings, identification, and characterization of bearing faults in motors via nondestructive evaluation (NDE) methods have been studied extensively, among which vibration analysis has been found to be a promising technique for early diagnosis of anomalies. However, a majority of the existing techniques rely on vibration sensors attached onto or in close proximity to the motor in order to collect signals with a relatively high SNR. Due to weight and space restrictions, these techniques cannot be used in unmanned aerial vehicles (UAVs), especially during flight operations since accelerometers cannot be attached onto motors in small UAVs. Small UAVs are often subjected to vibrational disturbances caused by multiple factors such as weather turbulence, propeller imbalance, or bearing faults. Such anomalies may not only pose risks to UAV’s internal circuitry, components, or payload, they may also generate undesirable noise level particularly for UAVs expected to fly in low-altitudes or urban canyon. This paper presents a detailed discussion of challenges in in-flight detection of bearing failure in UAVs using existing approaches and offers potential solutions to detect overall vibration anomalies in small UAV operations based on IMU data.


2021 ◽  
Vol 7 (6) ◽  
pp. 63447-63463
Author(s):  
Ivo Z. L. Meyer ◽  
José E. M. Barros ◽  
José E. M. Barros

Brushless motors are increasingly present in our lives and to get the best out of them it is important to know their performance. The objective of this work is to create a methodology of experimental characterization of this type of motor. As a methodology, research was done on similar works, it was built a test bench and an acquisition system to obtain the data. The variables measured were: rotation, torque, temperature, current and voltage. In addition to possessing a servo motor that acts like brake prony type to vary the load applied to the system. The results obtained allowed the analysis of the motor performance. It was also possible to design a mathematical model that represents the system, using the information obtained and the equations present in the literature. It was possible to conclude that the bench and the methodology used were valid, and that the ESC (electronic speed controller) is a great efficiency limiter of the motors.


2020 ◽  
Vol 10 (17) ◽  
pp. 5948 ◽  
Author(s):  
Alberto Fernández ◽  
Rubén Usamentiaga ◽  
Pedro de Arquer ◽  
Miguel Ángel Fernández ◽  
D. Fernández ◽  
...  

The efficiency and profitability of photovoltaic (PV) plants are highly controlled by their operation and maintenance (O&M) procedures. Today, the effective diagnosis of any possible fault of PV plants remains a technical and economic challenge, especially when dealing with large-scale PV plants. Currently, PV plant monitoring is carried out by either electrical performance measurements or image processing. The first approach presents limited fault detection ability, it is costly and time-consuming, and it is incapable of fast identification of the physical location of the fault. In the second approach, Infrared Thermography (IRT) imaging has been used for the characterization of PV module failures, but their setup and processing are rather complex and an experienced technician is required. The use of Unmanned Aerial Vehicles (UAVs) for IRT imaging of PV plants for health status monitoring of PV modules has been identified as a cost-effective approach that offers 10–-15 fold lower inspection times than conventional techniques. However, previous works have not performed a comprehensive approach in the context of automated UAV inspection using IRT. This work provides a fully automated approach for the: (a) detection, (b) classification, and (c) geopositioning of the thermal defects in the PV modules. The system has been tested on a real PV plant in Spain. The obtained results indicate that an autonomous solution can be implemented for a full characterization of the thermal defects.


2021 ◽  
Vol 31 (2) ◽  
pp. 67-74

Parachute recovery systems are proved to be an efficient method to recovery and rescue unmanned aerial vehicles (UAV) as it follows most requirements of reliability and airworthiness in flights. Parachutes are key components of the recovery systems and the drag coefficient of parachutes plays a crucial role in evaluating parachute’s performance. The purpose of the research is to determine and compare the impact of some factors on aerodynamic drag force during the inflation of a parachute. The canopy’s shape (flat circular type and extended skirt 10% flat type), of the length of suspension lines (be in proportion to nominal diameter from 0.6 to 1.5) are considered. Measurement of the drag force of the parachute models is carried out in an open return wind tunnel. Experimental results show that flat circular canopy has a higher drag coefficient than extended skirt 10% flat model in the range of low speed from 3 to 6 m/s. However, when wind speed is greater than 6 m/s, the drag coefficients of both two parachute types are nearly 0.85. In terms of the suspension line, the longer length would significantly raise the coefficient of drag force.


2020 ◽  
Vol 12 (11) ◽  
pp. 1711 ◽  
Author(s):  
Efstratios Karantanellis ◽  
Vassilis Marinos ◽  
Emmanuel Vassilakis ◽  
Basile Christaras

The increased development of computer vision technology combined with the increased availability of innovative platforms with ultra-high-resolution sensors, has generated new opportunities and fields for investigation in the engineering geology domain in general and landslide identification and characterization in particular. During the last decade, the so-called Unmanned Aerial Vehicles (UAVs) have been evaluated for diverse applications such as 3D terrain analysis, slope stability, mass movement hazard and risk management. Their advantages of detailed data acquisition at a low cost and effective performance identifies them as leading platforms for site-specific 3D modelling. In this study, the proposed methodology has been developed based on Object-Based Image Analysis (OBIA) and fusion of multivariate data resulted from UAV photogrammetry processing in order to take full advantage of the produced data. Two landslide case studies within the territory of Greece, with different geological and geomorphological characteristics, have been investigated in order to assess the developed landslide detection and characterization algorithm performance in distinct scenarios. The methodology outputs demonstrate the potential for an accurate characterization of individual landslide objects within this natural process based on ultra high-resolution data from close range photogrammetry and OBIA techniques for landslide conceptualization. This proposed study shows that UAV-based landslide modelling on the specific case sites provides a detailed characterization of local scale events in an automated sense with high adaptability on the specific case site.


2018 ◽  
Author(s):  
Karena A. McKinney ◽  
Daniel Wang ◽  
Jianhuai Ye ◽  
Jean-Baptiste de Fouchier ◽  
Patricia C. Guimarães ◽  
...  

2019 ◽  
Author(s):  
J. Ahokas ◽  
P. Le Guern ◽  
T. Slettemeas ◽  
E. Syrdalen ◽  
M. Etchebes ◽  
...  

Author(s):  
A.A. Moykin ◽  
◽  
A.S. Medzhibovsky ◽  
S.A. Kriushin ◽  
M.V. Seleznev ◽  
...  

Nowadays, the creation of remotely-piloted aerial vehicles for various purposes is regarded as one of the most relevant and promising trends of aircraft development. FAU "25 State Research Institute of Chemmotology of the Ministry of Defense of the Russian Federation" have studied the operation features of aircraft piston engines and developed technical requirements for motor oil for piston four-stroke UAV engines, as well as a new engine oil M-5z/20 AERO in cooperation with NPP KVALITET, LLC. Based on the complex of qualification tests, the stated operational properties of the experimental-industrial batch of M-5z/20 AERO oil are generally confirmed.


Sign in / Sign up

Export Citation Format

Share Document