scholarly journals Safe Documentation of Historical Monuments by an Autonomous Unmanned Aerial Vehicle

2021 ◽  
Vol 10 (11) ◽  
pp. 738
Author(s):  
Vít Krátký ◽  
Pavel Petráček ◽  
Tiago Nascimento ◽  
Michaela Čadilová ◽  
Milan Škobrtal ◽  
...  

The use of robotic systems, especially multi-rotor aerial vehicles, in the documentation of historical buildings and cultural heritage monuments has become common in recent years. However, the teleoperated robotic systems have significant limitations encouraging the ongoing development of autonomous unmanned aerial vehicles (UAVs). The autonomous robotic platforms provide a more accurate and safe measurement in distant and difficult to access areas than their teleoperated counterpart. Through the use of autonomous aerial robotic systems, access to such places by humans and building of external infrastructures like scaffolding for documentation purposes is no longer necessary. In this work, we aim to present a novel autonomous unmanned aerial vehicle designed for the documentation of hardly attainable areas of historical buildings. The prototype of this robot was tested in several historical monuments comprising scanned objects located in dark and hardly accessible areas in the upper parts of tall naves. This manuscript presents the results from two specific places: the Church of St. Anne and St. Jacob the Great in Stará Voda, and St. Maurice Church in Olomouc, both in the Czech Republic. Finally, we also compare the three-dimensional map obtained with the measurements made by the 3D laser scanner carried onboard UAV against the ones performed by a 3D terrestrial laser scanner.

Author(s):  
Jun Tang ◽  
Jiayi Sun ◽  
Cong Lu ◽  
Songyang Lao

Multi-unmanned aerial vehicle trajectory planning is one of the most complex global optimum problems in multi-unmanned aerial vehicle coordinated control. Results of recent research works on trajectory planning reveal persisting theoretical and practical problems. To mitigate them, this paper proposes a novel optimized artificial potential field algorithm for multi-unmanned aerial vehicle operations in a three-dimensional dynamic space. For all purposes, this study considers the unmanned aerial vehicles and obstacles as spheres and cylinders with negative electricity, respectively, while the targets are considered spheres with positive electricity. However, the conventional artificial potential field algorithm is restricted to a single unmanned aerial vehicle trajectory planning in two-dimensional space and usually fails to ensure collision avoidance. To deal with this challenge, we propose a method with a distance factor and jump strategy to resolve common problems such as unreachable targets and ensure that the unmanned aerial vehicle does not collide into the obstacles. The method takes companion unmanned aerial vehicles as the dynamic obstacles to realize collaborative trajectory planning. Besides, the method solves jitter problems using the dynamic step adjustment method and climb strategy. It is validated in quantitative test simulation models and reasonable results are generated for a three-dimensional simulated urban environment.


2019 ◽  
Vol 35 (3) ◽  
pp. 367-376 ◽  
Author(s):  
Qiang Shi ◽  
Hanping Mao ◽  
Xianping Guan

Abstract. To analyze the droplet deposition under the influence of the flow field of an unmanned aerial vehicle (UAV), a hand-held three-dimensional (3D) laser scanner was used to scan 3D images of the UAV. Fluent software was used to simulate the motion characteristics of droplets and flow fields under the conditions of a flight speed of 3 m/s and an altitude of 1.5 m. The results indicated that the ground deposition concentration in the nonrotor flow field was high, the spray field width was 2.6 m, and the droplet deposition concentration was 50 to 200 ug/cm2. Under the influence of the rotor flow field, the widest deposition range of droplets reached 12.8 m. Notably, the droplet deposition uniformity worsened, and the concentration range of the droplet deposition was 0 to 500 ug/cm2. With the downward development of the downwash flow field, the overall velocity of the flow field gradually decreased, and the influence interval of the flow field gradually expanded. In this article, the droplet concentration was verified under simulated working conditions by a field experiment, thereby demonstrating the reliability of the numerical simulation results. This research could provide a basis for determining optimal UAV operating parameters, reducing the drift of droplets and increasing the utilization rate of pesticides. Keywords: Unmanned aerial vehicle (UAV), Aerial application, Downwash flow field, Droplet deposition, Simulation analysis.


2021 ◽  
Vol 25 (1) ◽  
pp. 143-154
Author(s):  
Mohd Azwan Abbas ◽  
Khairulazhar Zainuddin ◽  
Norhadija Darwin ◽  
Mohamad Aizat Asyraff Mohamad Azmi ◽  
Yusuf Drisu Opaluwa ◽  
...  

2017 ◽  
Vol 17 (5) ◽  
pp. 1056-1072 ◽  
Author(s):  
Daniel Reagan ◽  
Alessandro Sabato ◽  
Christopher Niezrecki

Quantifying the condition of aging structures is important to verify structural integrity and long-term reliability. Structural health monitoring plays a key role in the prevention of catastrophic failure, in improving the safety of infrastructure, and in reducing the downtime and costs associated with their maintenance. Bridges are typically designed to have a lifespan on order of 50 years; therefore, bridge monitoring is important since many of them are near to or have already exceeded their design life. Conventional sensors and examination techniques such as accelerometers and strain gages produce results at only a discrete number of points. Visual inspection only provides qualitative information and is subject to human variability and inconsistencies between inspectors. Moreover, both approaches are labor intensive and time-consuming. In recent years, three-dimensional digital image correlation systems have proven their efficiency in being able to provide accurate quantitative information of structural deformations, full-field strain, and geometry profiles of large-scale structures. At the same time, unmanned aerial vehicles have emerged as valuable tools for remotely performing measurements in places, which are either difficult or dangerous to access. With regard to bridge inspection, unmanned aerial vehicles have the capability to expedite the measurement process, offer increased accessibility, and reduce interference with the structures’ functionality. In this study, a novel approach that combines the use of an unmanned aerial vehicle and three-dimensional digital image correlation is developed to perform non-contact, optically based measurements to monitor the health of bridges. Extensive laboratory tests and a long-term monitoring campaign on two in-service concrete bridges demonstrated the accuracy of this system in detecting structural changes. Results show that this system is able to detect changes to the bridge geometry with an uncertainty on the order of 10−5 m while improving accessibility. The feasibility of the approach, best practices, and lessons learned is presented.


2021 ◽  
Vol 11 (13) ◽  
pp. 5772
Author(s):  
Dawid Lis ◽  
Adam Januszko ◽  
Tadeusz Dobrocinski

The purpose of this article is to present and discuss the results of a non-standard unnamed aerial vehicle construction with a constant cross-section square-shaped avionic profile. Based on the model’s in-air observed maneuverability, the research of avionic construction behavior was carried out in a water tunnel. The results show the model’s specific lift capabilities in comparison to classical avionic constructions. The characteristic results of the lift coefficient showed that the unmanned aerial vehicle presents favorable features than classic avionic constructions. The model was created with the prospect of using it in the future for dual-use purposes, where unmanned aerial vehicles are currently experiencing very rapid development. When creating the prototype, the focus was on low production cost, as well as convenience in operation. The development of this type of breakthrough avionic solution, which shows extraordinary maneuverability, may contribute to increasing the popularity and, above all, the availability of unmanned aerial vehicles for the largest possible group of recipients because of high avionic properties in relation to the technical construction complexity.


Author(s):  
E. G. Semenova ◽  
◽  
M. I. Bakustina ◽  

The article is devoted to the creation of a method for preparing an unmanned aerial vehicle for implementation as a finished packaged product. To achieve the goal, modern methods of standardization and quality control are used.


Author(s):  
Hongbo Xin ◽  
Yujie Wang ◽  
Xianzhong Gao ◽  
Qingyang Chen ◽  
Bingjie Zhu ◽  
...  

The tail-sitter unmanned aerial vehicles have the advantages of multi-rotors and fixed-wing aircrafts, such as vertical takeoff and landing, long endurance and high-speed cruise. These make the tail-sitter unmanned aerial vehicle capable for special tasks in complex environments. In this article, we present the modeling and the control system design for a quadrotor tail-sitter unmanned aerial vehicle whose main structure consists of a traditional quadrotor with four wings fixed on the four rotor arms. The key point of the control system is the transition process between hover flight mode and level flight mode. However, the normal Euler angle representation cannot tackle both of the hover and level flight modes because of the singularity when pitch angle tends to [Formula: see text]. The dual-Euler method using two Euler-angle representations in two body-fixed coordinate frames is presented to couple with this problem, which gives continuous attitude representation throughout the whole flight envelope. The control system is divided into hover and level controllers to adapt to the two different flight modes. The nonlinear dynamic inverse method is employed to realize fuselage rotation and attitude stabilization. In guidance control, the vector field method is used in level flight guidance logic, and the quadrotor guidance method is used in hover flight mode. The framework of the whole system is established by MATLAB and Simulink, and the effectiveness of the guidance and control algorithms are verified by simulation. Finally, the flight test of the prototype shows the feasibility of the whole system.


Author(s):  
Salim A. Mouloua ◽  
James Ferraro ◽  
Mustapha Mouloua ◽  
P.A. Hancock

The present study was designed to examine the research trends in the literature focusing on Human Factors issues relevant to Unmanned Aerial Vehicle (UAV) systems. As these UAV technologies continue to proliferate with increasing autonomy and supervisory control requirements, it is crucial to evaluate the current and emerging research trends across the generations. This paper reviews the research trends of 228 papers matching our search criteria. The search retained only relevant and complete papers published over the past thirty years (1988-2017) in the Proceedings of the Human Factors and Ergonomics Society. Results were tabulated, graphed, and discussed based on research categories, topic areas, authors’ affiliation, and sources of funding. Results showed a substantial increase in the number of articles in the last two decades, with most papers driven by academic institutions and military and government agencies.


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