scholarly journals Aerodynamic efficiency and performance enhancement of fixed-wing unmanned aerial vehicles using novel configurations and techniques

2018 ◽  
Author(s):  
Περικλής Παναγιώτου
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Performance Enhancement ◽  
Operating Conditions ◽  
Aerodynamic Efficiency ◽  
Aerial Vehicles ◽  
And Performance

Ο σκοπός της διδακτορικής διατριβής είναι η βελτιστοποίηση της αεροδυναμικής απόδοσης και των επιδόσεων Μη-Επανδρωμένων Αεροχημάτων (ΜΕΑ) σταθερής πτέρυγας, μεγάλης αυτονομίας και μέσου ύψους (MALE UAV ή tactical UAV – NATO classification), που επιχειρούν σε συνθήκες πτήσης με Mach < 0.3. Πρόκειται για μια πλήρη τεχνολογική έρευνα, τα βασικά αντικείμενα της οποίας είναι α) η διερεύνηση της ροής γύρω από ΜΕΑ σταθερής πτέρυγας, β) η ανάλυση του ισοζυγίου οπισθέλκουσας δύναμης και εντοπισμός των κύριων πηγών αυτής, γ) η αναζήτηση, καταγραφή, και αξιολόγηση πιθανών τεχνολογιών, γεωμετριών, και τεχνικών για τη βελτίωση της αεροδυναμικής απόδοσης και των επιδόσεων ΜΕΑ (technology screening), δ) η επιλογή και λεπτομερής διερεύνηση των γεωμετριών που δυνητικά προσφέρουν τα περισσότερα πλεονεκτήματα, και ε) η εφαρμογή των παραπάνω σε εφαρμοσμένες μελέτες σχεδιασμού ΜΕΑ για αξιολόγηση και εκτίμηση επιδόσεων. Σε αντίθεση με τις υπάρχουσα βιβλιογραφία, η παρούσα έρευνα προσεγγίζει ολιστικά τον σχεδιασμό και την βελτιστοποίηση των ΜΕΑ σταθερής πτέρυγας, εκκινώντας από θεμελιώδεις ρευστοδυναμικές αναλύσεις, συνεχίζοντας με παραμετρικές αναλύσεις αεροδυναμικής, και κλείνοντας με εφαρμογή σε ολοκληρωμένες μελέτες σχεδιασμού. Για αυτό το σκοπό χρησιμοποιείται μια πληθώρα εργαλείων, που περιλαμβάνουν λογισμικά υπολογιστικής μοντελοποίησης, πειραματικές διατάξεις και τεχνικές, καθώς επίσης και αναλυτικά εργαλεία διαστασιολόγησης, και υπολογισμού παραμέτρων αεροδυναμικής, ευστάθειας και επιδόσεων αεροχημάτων, που αναπτύχθηκαν στα πλαίσια της διατριβής (in-house tools). Αρχικά καθορίζεται και σχεδιάζεται μια γεωμετρία αναφοράς ΜΕΑ, της οποίας οι προδιαγραφές (requirements) και οι επιχειρησιακές συνθήκες (operating conditions) ορίζονται επίσης ως σημεία αναφοράς. Η ροή γύρω από το ΜΕΑ αναλύεται χρησιμοποιώντας τα εργαλεία αεροδυναμικής ανάλυσης και πραγματοποιείται μια ταξινόμηση της οπισθέλκουσας δύναμης (drag bookkeeping), τόσο για την κύρια πτέρυγα, όσο και για την συνολική γεωμετρία του ΜΕΑ. Στη συνέχεια, ερευνάται μια πληθώρα πιθανών επιλογών, τεχνολογιών, τεχνικών και γεωμετριών, που δυνητικά μπορεί να βελτιώσουν την επίδοση των ΜΕΑ σταθερής πτέρυγας. Δύο είδη γεωμετριών επιλέγονται τελικά για ενδελεχή μελέτη και περεταίρω ανάλυση, και συγκεκριμένα, τα winglets και τα σώματα BWB. Οι γεωμετρίες αυτές αναλύονται διεξοδικά σε υπολογιστικό, πειραματικό, και σχεδιαστικό επίπεδο. Όπως πιστοποιείται και από τις σχετικές επιστημονικές δημοσιεύσεις, η έρευνα οδηγεί σε πρωτότυπα συμπεράσματα και παρατηρήσεις που αφορούν τα ροϊκά φαινόμενα, και σε ανάπτυξη εξειδικευμένων μεθοδολογιών σχεδιασμού για εφαρμογές ΜΕΑ σταθερής πτέρυγας. Γίνεται επίσης και αποτίμηση των πλεονεκτημάτων της χρήσης των γεωμετριών αυτών, με τα αποτελέσματα να δείχνουν βελτίωση της τάξεως του 10% και 30% για τα winglets και τις πλατφόρμες BWB αντίστοιχα, όσον αφορά την αεροδυναμική απόδοση. Συνοψίζοντας, η διατριβή επικεντρώνεται στα ΜΕΑ τύπου MALE/tactical, λόγω του ότι αποτελούν το μεγαλύτερο κομμάτι της αγοράς των ΜΕΑ. Ωστόσο, με την προϋπόθεση ότι οι λόγοι ροϊκής ομοιότητας και οι επιχειρησιακές συνθήκες είναι πανομοιότυπες, οι προτεινόμενες μέθοδοι και τα επαγόμενα συμπεράσματα μπορούν να επεκταθούν και σε οποιοδήποτε άλλο αερόχημα σταθερής πτέρυγας, από ΜΕΑ μεγαλύτερης κλίμακας, μέχρι υπερ-ελαφρά ή ελαφρά αεροχήματα και μεταγωγικά αεροσκάφη. Επιπρόσθετα, η έρευνα που αφορά είτε σε στοιχειώδη ρευστοδυναμικά φαινόμενα, όπως είναι οι δίνες ακροπτερυγίου, είτε στις βελτιωτικές διατάξεις (winglets, BWB) έχει προεκτάσεις και σε άλλες εφαρμογές μεγαλύτερης κλίμακας, που αφορούν την κοινωνία και την βιομηχανία, όπως είναι για παράδειγμα τα επιβατηγά αεροσκάφη και οι εναέριες μεταφορές.

Protection of a Stationary Object from the Massive Impact of Mobile Objects under Conditions of von Neumann's Mixed Game

2021 ◽  
Vol 27 (10) ◽  
pp. 521-530
Author(s):  
O. N. Maslov ◽  
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Simulation Modeling ◽  
Statistical Simulation ◽  
Operating Conditions ◽  
Protection System ◽  
Stationary Object ◽  
Physical Protection ◽  
Mobile Objects ◽  
Aerial Vehicles ◽  
Statistical Risk

The method of statistical simulation modeling (SSM) has been used to analyze the operating conditions and the efficiency of the physical protection system of a stationary object from the massive impact of unmanned aerial vehicles (drones). It is shown that the conditions of the problem correspond to the reflexive version of a two-sided von Neumann's mixed game. statistical risk-oriented characteristics for two variants of the object protection system implementation using force mechanical and electromagnetic effects on the "drones cloud" are determined. The possibilities and the prospects for using the results obtained using the SSM method are presented.

scholarly journals Simulation and Test of Discrete Mobile Surfaces for a RC-Aircraft

Aerospace ◽  
2019 ◽  
Vol 6 (11) ◽  
pp. 122
Author(s):  
Francesco Nicassio ◽  
Gennaro Scarselli
Keyword(s):  
Composite Materials ◽  
Unmanned Aerial Vehicles ◽  
Composite Plate ◽  
Stacking Sequence ◽  
Total Thickness ◽  
Aerodynamic Efficiency ◽  
Aerodynamic Pressure ◽  
Aerial Vehicles ◽  
Discrete Surface ◽  
Lever Effect

Morphing structures suitable for unmanned aerial vehicles (UAVs) have been investigated for several years. This paper presents a novel lightweight, morphing concept based on the exploitation of the “lever effect” of a bistable composite plate that can be integrated in an UAV horizontal tail. Flight dynamics equations are solved in Simulink environment, thus being able to simulate and compare different flight conditions with conventional and bistable command surfaces. Subsequently, bistable plates are built by using composite materials, paying particular attention to dimensions, asymmetric stacking sequence and total thickness needed to achieve bistability. NACA0011 airfoil is chosen for proving this concept. Wind tunnel tests demonstrate that the discrete surface is capable of withstanding the aerodynamic pressure. A remotely piloted vehicle is employed to test the discrete horizontal tail command during the take-off. The results show that, choosing a proper configuration of constraints, stacking sequence and aspect ratio for the bistable laminate, it is possible to tailor the snap-through mechanism. The proposed concept appears lighter and increases aerodynamic efficiency when compared to conventional UAV command surfaces.

scholarly journals Classification of robotic battery service systems for unmanned aerial vehicles

2018 ◽  
Vol 161 ◽  
pp. 03023
Author(s):  
Tien Ngo ◽  
Mehmet Guzey ◽  
Vladimir Dashevsky
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Power Supply ◽  
Landing Site ◽  
Operating Conditions ◽  
Joint Work ◽  
Operator Experience ◽  
Aerial Vehicles ◽  
Robotic Platforms ◽  
Algorithmic Model

Existing examples of prototypes of ground-based robotic platforms used as a landing site for unmanned aerial vehicles are considered. In some cases, they are equipped with a maintenance mechanism for the power supply module. The main requirements for robotic multi-copter battery maintenance systems depending on operating conditions, required processing speed, operator experience and other parameters are analyzed. The key issues remain questions of the autonomous landing of the unmanned aerial vehicles on the platform and approach to servicing battery. The existing prototypes of service robotic platforms are differed in the complexity of internal mechanisms, speed of service, algorithms of joint work of the platform and unmanned aerial vehicles during the landing and maintenance of the battery. The classification of robotic systems for servicing the power supply of multi-copter batteries criteria is presented using the following: the type of basing, the method of navigation during landing, the shape of the landing pad, the method of restoring the power supply module. The proposed algorithmic model of the operation of battery power maintenance system of the multi-copter on ground-based robotic platform during solving the target agrarian problem is described. Wireless methods of battery recovery are most promising, so further development and prototyping of a wireless charging station for multi-copter batteries will be developed.

scholarly journals Aerodock (a smart, autonomous charging and docking station for unmanned aerial vehicles)

2022 ◽  
Vol 2161 (1) ◽  
pp. 012058
Author(s):  
Laaboni Mukerjee ◽  
Mukul Yadav ◽  
Amit Choraria ◽  
Atharv Tendolkar ◽  
Arjun Hariharan ◽  
...  
Keyword(s):  
Cloud Computing ◽  
Unmanned Aerial Vehicles ◽  
Performance Optimization ◽  
Wireless Power Transfer ◽  
External Factors ◽  
Battery Management ◽  
Human Intervention ◽  
Wireless Power ◽  
Aerial Vehicles ◽  
And Performance

Abstract The COVID-19 pandemic has laid bare the need for contactless operations. While unmanned aerial vehicles (UAVs) are being developed to aid humans in countless domains, the need for effective battery management and performance optimization remains a huge task. The proposed solution, the “AeroDock”, aims to tackle these challenges by using wireless power transfer (WPT) technology coupled with smart monitoring of the drone’s health. The performance and hardware checks are assessed at the user end via cloud computing and IoT technology. This system is contact-less, safe, reliable and its usage is not affected by external factors. Thus, the AeroDock is a smart docking station for UAVs which eliminates the need for human intervention in effective charging and maintenance.

Viability of joined flight for small unmanned aerial vehicles

2019 ◽  
Vol 124 (1273) ◽  
pp. 297-322
Author(s):  
E. Levis ◽  
F. Pleho ◽  
J. Hedges
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Parametric Analysis ◽  
Aircraft Design ◽  
Relative Magnitude ◽  
Design Parameters ◽  
Wing Loading ◽  
Aerodynamic Efficiency ◽  
Aspect Ratios ◽  
Aerial Vehicles ◽  
Better Than

ABSTRACTThe range of small, electrically powered UAVs is still limited by the mass specific energy of batteries. This paper investigates the idea that, in cases where multiple aircraft must transit to the same location, savings in mass or an extension of achievable range are possible when they join wingtip-to-wingtip. The viability of joined flight is investigated by quantifying the relative magnitude of savings resulting from increased aerodynamic efficiency and that of penalties due to the increased structural and component weights. Through a parametric analysis the level of savings achievable is found to be greatly dependent on the proportion of the flight spent in a joined configuration and aircraft design parameters such as wing loading, aspect ratio and the added weight of the joining mechanism. A custom, multidisciplinary UAV sizing algorithm is presented and utilised to design several sample aircraft, featuring two different joining mechanism architectures. The results verify the findings of the parametric study and indicate that mass savings are possible only for moderate to low aspect ratios, with semi-permanent magnetic joining mechanism performing better than rigid structural ones, even when the joined fight segment accounts for only 30% of the total airborne time.

Performance Measurements of a 1/6-Scale Model of the 1907 Cornu Rotor

2012 ◽  
Vol 57 (3) ◽  
pp. 1-5
Author(s):  
Benjamin Hance ◽  
J. Gordon Leishman ◽  
Joseph Milluzzo
Keyword(s):  
Aspect Ratio ◽  
Figure Of Merit ◽  
Ground Effect ◽  
Operating Conditions ◽  
Scale Model ◽  
Performance Measurements ◽  
Aerodynamic Efficiency ◽  
Rotor Design ◽  
Average Profile ◽  
And Performance

Measurements of the performance of an approximate 1/6-scale Cornu 1907 rotor system are discussed. The rotor was tested in hover, both in and out of ground effect, over a range of rotational speeds and collective blade pitch angles. The measurements showed that the rotor had low aerodynamic efficiency, with a maximum attainable figure of merit of only about 0.35 for out of ground effect operating conditions. An analysis of the measurements showed that the performance of this rotor is dominated by relatively high induced losses, with an average induced power factor of over two, mainly because of the use of low-aspect-ratio blades. Extrapolation of the performance polar back to zero thrust with the aid of modified momentum theory suggests that the average profile drag coefficient for the blade sections was of the order of 0.1. However, even with the benefits of a proper airfoil section of lower drag, it is shown that without also using a blade design of higher aspect ratio, the figure of merit of the Cornu rotor design could not be improved much above 0.4. The measured results confirm previous modeling assumptions used for the aerodynamic and performance analysis of the Cornu rotor design and conclusions drawn regarding the unfeasibility of successful free flights of the Cornu helicopter.

The Control of Humidification and Dew Condensation by Using of On/Off Control of the Bubble Humidifier in the PEMFC

2012 ◽  
Vol 155-156 ◽  
pp. 856-860
Author(s):  
Young Guan Jung ◽  
Ho Sang Choi ◽  
Du Hee Kim ◽  
Dae Heum Park
Keyword(s):  
Fuel Cell ◽  
Proton Conductivity ◽  
Proton Exchange Membrane ◽  
Performance Enhancement ◽  
Flow Channel ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Visualization Experiment ◽  
And Performance ◽  
Exchange Membrane

The performance of Proton Exchange Membrane Fuel Cell (PEMFC) is known to be influenced by different operating conditions such as temperature, pressure, and humidification of the reactant gases. Especially, the humidification is essential for the electrolysis and performance enhancement of PEMFC, because the proton conductivity depends on the hydration of proton exchange membrane. In this study, the humidification experiment has been done concerning ON/OFF control of the humidification for PEMFC, by using of the bubble humidifiers which are usually difficult to approximation control the humidity. Also, in order to verify the dew condensation, the visualization experiment has been done at a flow channel of PEMFC stack. As the results, it is possible to approximation control the humidity by using of the solenoid on/off valve in the bubble humidifier. The dew condensation is also verified through such experiment. The problems, such as the approximation control of humidity and dew condensation, were then resolved in such a useful manner.

scholarly journals Presenting an Effective Method to Detect and Track the Broken Path in VANET Using UAVs

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Zohreh Bakhtiari ◽  
Rozita Jamili Oskouei ◽  
Mona Soleymani ◽  
Akhtar Hussain Jalbani
Keyword(s):  
Cloud Computing ◽  
Unmanned Aerial Vehicles ◽  
Urban Areas ◽  
Vehicular Ad Hoc Networks ◽  
Ad Hoc ◽  
High Mobility ◽  
Geographic Routing ◽  
Negative Influence ◽  
Aerial Vehicles ◽  
And Performance

The routing process in vehicular ad hoc networks (VANETs) is a challenging task in urban areas which is due to the high mobility of vehicles, repetitive defects of the communication path, and the various barriers that may affect the reliability of data transmission and routing. Accordingly, the connectivity in vehicular communications has received the researchers’ attention, so different geographic routing protocols have been proposed in this respect. Unmanned aerial vehicles (UAVs) are useful for overcoming routing constraints. Cloud computing has also been defined as a new infrastructure for VANET which is made up of a significant number of computing nodes including stable data centers as well as a set of mobile computing devices embedded on vehicles. The aim of this research is to simulate a VANET in an urban area using cloud computing infrastructure and applying unmanned aerial vehicles (UAV) so that the negative influence of barriers in packet delivery and routing is avoided. To evaluate, the proposed method is compared with the basic protocol ClouDiV. Ns-2 simulation results show that the proposed method outperforms with different densities and variable times in terms of efficiency and performance.

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