scholarly journals Real-Time Obstacle Avoidance for Manned/Unmanned Aircraft Cooperative System Based on Improved Velocity Obstacle Method

2020 ◽  
Vol 38 (2) ◽  
pp. 309-318
Author(s):  
Yue Li ◽  
Wei Han ◽  
Qingyang Chen ◽  
Yong Zhang
Keyword(s):  
Real Time ◽  
Obstacle Avoidance ◽  
Three Dimensional ◽  
Unmanned Aircraft ◽  
Cooperative System ◽  
Flight Mode ◽  
Multi Agent ◽  
The Difference ◽  
The Right ◽  
Velocity Obstacle

To adapt the autonomous level of agents in current, and to perform the advantages of multi-agent in air combat, the form of manned/unmanned aircraft cooperative system has gradually become a hot topic. To solve the issue of three-dimensional (3D) real-time obstacle avoidance, the 3D maneuvering obstacle model is established firstly based on the traditional velocity obstacle method. Then the flight mode is selected and the optimal obstacle avoidance plane is determined by setting the Right-of-way rules when the system encountering obstacles. Finally, the difference of obstacle avoidance plane, the feasibility of avoiding maneuvering obstacle and the effectiveness of obstacle avoidance of cooperative system are verified by several flight simulations. The results show that the proposed method can realize the avoidance of 3D maneuvering obstacle for manned/unmanned aircraft cooperative system safely and efficiently.

CALCULATION OF THE DEPENDENCE OF THE DISTANCE TO THE LOCATED OBJECT FROM THE CORNER POSITION OF THE VEHICLE LINE

2018 ◽  
pp. 14-18
Author(s):  
V. V. Artyushenko ◽  
A. V. Nikulin
Keyword(s):  
Real Time ◽  
Statistical Physics ◽  
Angular Position ◽  
Three Dimensional ◽  
Line Of Sight ◽  
Two Dimensional ◽  
Radar Station ◽  
Flight Mode ◽  
Vector Algebra ◽  
Analytical Expressions

To simulate echoes from the earth’s surface in the low flight mode, it is necessary to reproduce reliably the delayed reflected sounding signal of the radar in real time. For this, it is necessary to be able to calculate accurately and quickly the dependence of the distance to the object being measured from the angular position of the line of sight of the radar station. Obviously, the simplest expressions for calculating the range can be obtained for a segment or a plane. In the text of the article, analytical expressions for the calculation of range for two-dimensional and three-dimensional cases are obtained. Methods of statistical physics, vector algebra, and the theory of the radar of extended objects were used. Since the calculation of the dependence of the range of the object to the target from the angular position of the line of sight is carried out on the analytical expressions found in the paper, the result obtained is accurate, and due to the relative simplicity of the expressions obtained, the calculation does not require much time.

scholarly journals The effect of prosthetic torsional stiffness on the golf swing kinematics of a left and a right-sided trans-tibial amputee

2004 ◽  
Vol 28 (2) ◽  
pp. 121-131 ◽  
Author(s):  
J. P. Rogers ◽  
S. C. Strike ◽  
E. S. Wallace
Keyword(s):  
Ankle Joint ◽  
Perceived Stress ◽  
Sagittal Plane ◽  
Three Dimensional ◽  
Transverse Plane ◽  
Golf Swing ◽  
Torsional Stiffness ◽  
The Difference ◽  
The Right ◽  
Socket Interface

The golf swing is a biomechanically complex movement requiring three-dimensional movements at the ankle joint complex (AJC), the hips and shoulders. Trans-tibial amputees lose the natural AJC movements as many prostheses do not allow three dimensional foot movements. Torsion devices have been developed and incorporated into prostheses to facilitate internal and external transverse plane rotations. These devices can help amputees to compensate for the loss of movement and to reduce shearing stresses at the stump-socket interface. The primary aim of the present study was to investigate the effects of three torsion devices on body rotations during the golf swing. Two trans-tibial amputees (one right-sided and one left-sided) were analysed using three-dimensional video analysis at address (ADR), the top of the backswing (TBS) and at the end of the follow-through (EFT). The participants played shots with a 3-wood under three different prosthetic conditions (two with a torsion device set to different stiffness values, and one with no torsion device). The results showed that the torsion device served to improve the hip and shoulder rotations of the left-side amputee without increasing perceived stress at the stump. The torsion device had minimal effect on the hip and shoulder rotations of the right-side amputee, although perceived stress was reduced. The difference in results between the right-sided and left-sided amputees was due to the different requirements of each foot during the golf swing. The main problem faced by the right-side amputee was a loss of the sagittal plane movement of ankle joint plantarflexion at EFT, rather than the transverse plane movement.

scholarly journals Pulmonary acini exhibit complex changes during postnatal rat lung development

2019 ◽  
Author(s):  
David Haberthür ◽  
Eveline Yao ◽  
Sébastien F. Barré ◽  
Tiziana P. Cremona ◽  
Stefan A. Tschanz ◽  
...  
Keyword(s):  
Lung Development ◽  
Three Dimensional ◽  
Rat Lung ◽  
Voxel Size ◽  
Synchrotron Facility ◽  
Coefficients Of Variation ◽  
Swiss Light Source ◽  
The Mean ◽  
The Difference ◽  
The Right

AbstractPulmonary acini represent the functional gas-exchanging units of the lung. Due to technical limitations, individual acini cannot be identified on microscopic lung sections. To overcome these limitations, we imaged the right lower lobes of instillation-fixed rat lungs from postnatal days P4, P10, P21, and P60 at the TOMCAT beamline of the Swiss Light Source synchrotron facility at a voxel size of l.48μm. Individual acini were segmented from the three-dimensional data by closing the airways at the transition from conducting to gas exchanging airways. For a subset of acini (N=268), we followed the acinar development by stereologically assessing their volume and their number of alveoli. We found that the mean volume of the acini increases 23 times during the observed timeframe. The coefficients of variation dropped from 1.26 to 0.49 and the difference between the mean volumes of the fraction of the 20 % smallest to the 20 % largest acini decreased from a factor of 27.26 (day 4) to a factor of 4.07 (day 60), i.e. shows a smaller dispersion at later time points. The acinar volumes show a very large variation early in lung development and homogenize during maturation of the lung by reducing their size distribution by a factor of 7 until adulthood. The homogenization of the acinar sizes hints at an optimization of the gas-exchange region in the lungs of adult animals and that acini of different size are not evenly distributed in the lungs. This likely leads to more homogeneous ventilation at later stages in lung development.

APPLICATION OF AERIAL PHOTOGRAPHY RESULTS, OBTAINED USING UAV DATA TO ESTIMATE THE RESIDUAL CAPACITY OF THE LANDFILL. PRACTICE OF THE REPUBLIC OF TATARSTAN

2021 ◽  
Vol 31 (4) ◽  
pp. 404-415
Author(s):  
L.G. Akhmetzyanova ◽  
B.M. Usmanov ◽  
R.S. Kuz’min ◽  
A.M. Gafurov ◽  
V.V. Sirotkin ◽  
...  
Keyword(s):  
Aerial Photography ◽  
Three Dimensional ◽  
Unmanned Aircraft ◽  
Actual State ◽  
Active Monitoring ◽  
Satellite Navigation System ◽  
Residual Capacity ◽  
The Difference ◽  
The Republic ◽  
Project Data

Assessment of the current residual capacity is a fundamentally important task, the solution of which is demonstrated on a landfill located in the Republic of Tatarstan. To solve the task, the modern methods of high-precision three-dimensional reconstruction were used based on the survey from an unmanned aircraft DJI Phantom 4, equipped with a global satellite navigation system (GNSS) receiver. As a result of combining the project data and data from field surveys into one coordinate system and elevations and reconstruction of designed underground and ground parts of landfill calculation, the difference of models and the residual capacity of the landfill becomes possible. Based on the materials considered as of July 2020, the residual capacity of the studied landfill is 41.2 % of the project capacity, which allows us to continue to operate this landfill. The proposed approach allows for rapid and high-quality active monitoring of the engineered facility. Photogrammetric processing of the results of low-altitude aerial photography makes it possible to obtain objective data on the current actual state of the landfills, to carry out competent and valid management of the landfill functioning. Significant, this will extend the landfill's lifetime, minimize the adverse effects on the environment and predict the yield to the project capacity much more accurately.

CT Image Measurement and Analysis of the Influence of Different Motion Modes on the Geometrical Morphology of Carpal Bone

2020 ◽  
Vol 10 (4) ◽  
pp. 913-917
Author(s):  
Zegang Wang
Keyword(s):  
Three Dimensional ◽  
Ct Imaging ◽  
Bone Volume ◽  
Carpal Bone ◽  
Left Hand ◽  
Motion Modes ◽  
Measurement And Analysis ◽  
The Difference ◽  
The Right ◽  
Capitate Bone

The purpose of this study is to explore the influence of different movement modes on the geometrical morphology of carpal bones. In this study, Computed Tomography (CT) imaging is used for measurement and analysis. The results show that the changes of wrist bone volume of athletes are not significant compared with that of non-athletes, and the changes of bone density of the wrist bone are more obvious under the motion stress stimulation. According to results of CT imaging measurement and calculation, the average CT values of triangular bone, trapezoid bone, capitate bone and pisiform bone in the left hand and hamate bone in the right hand of the athlete are greater than that of the non-athlete, and the difference is statistically significant. Therefore, CT imaging technology can help to reconstruct the three-dimensional image of the carpal bone and deeply understand the geometric shape of the carpal bone of athletes.

scholarly journals Three-Dimensional Visualization System with Spatial Information for Navigation of Tele-Operated Robots

Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 746 ◽  
Author(s):  
Seung-Hun Kim ◽  
Chansung Jung ◽  
Jaeheung Park
Keyword(s):  
Real Time ◽  
Spatial Information ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Effective Control ◽  
Visualization System ◽  
Level Information ◽  
Surrounding Space ◽  
The Right ◽  
High Level

This study describes a three-dimensional visualization system with spatial information for the effective control of a tele-operated robot. The environmental visualization system for operating the robot is very important. The tele-operated robot performs tasks in a disaster area that is not accessible to humans. The visualization system should perform in real-time to cope with rapidly changing situations. The visualization system should also provide accurate and high-level information so that the tele-operator can make the right decisions. The proposed system consists of four fisheye cameras and a 360° laser scanner. When the robot moves to the unknown space, a spatial model is created using the spatial information data of the laser scanner, and a single-stitched image is created using four images from cameras and mapped in real-time. The visualized image contains the surrounding spatial information; hence, the tele-operator can not only grasp the surrounding space easily, but also knows the relative position of the robot in space. In addition, it provides various angles of view without moving the robot or sensor, thereby coping with various situations. The experimental results show that the proposed method has a more natural appearance than the conventional methods.

The Hypoplasic Mandible: What Makes it Different From the Healthy Child?

2020 ◽  
pp. 105566562097230
Author(s):  
Floriane Remy ◽  
Yves Godio-Raboutet ◽  
Guillaume Captier ◽  
Pierre Bonnaure ◽  
Philippe Burgart ◽  
...  
Keyword(s):  
Supervised Classification ◽  
Three Dimensional ◽  
Growth Period ◽  
P Value ◽  
First Year ◽  
Healthy Children ◽  
Mandibular Hypoplasia ◽  
The Difference ◽  
The Right ◽  
First Year Of Life

Objective: This study aimed to analyze the morphology of the hypoplasic mandible and its evolution during the growth period to better understand how it differs from the pediatric healthy mandible. Method: Three-dimensional mandibular models of hypoplasic and healthy children aged from 39 gestational weeks to 7 years old were analyzed with a morphometric method including data clustering. Morphological distinctions between pathological and healthy mandibles were highlighted. Bilateral and unilateral mandibular hypoplasia were distinguished. Results: The study sample was composed of 31 hypoplasic children and as many sex- and age-matched healthy children. Morphological distinctions between pathological and healthy mandibles were highlighted only from the first year of life. In bilateral hypoplasia, the overall mandibular dimensions were reduced while there was only a ramus asymmetry in unilateral mandibular hypoplasia (mean ± SD of the difference between the Grp03c and Grp03b subgroups: 6.80 ± 6.37 – P value = 1.64e–3 for the height of the left ramus versus 0.18 ± 4.18 – P value = .82 for the height of the right ramus). Supervised classification trees were built to identify the pathology and discriminate unilateral from bilateral mandibular hypoplasia (prediction rates = 81% and 84%, respectively). Conclusions: Based on a morphometric analysis, we demonstrated that mandibular hypoplasia significantly impacts the mandibular morphology only from the first year of life, with a distinction between bilateral and unilateral hypoplasia.

Research on Multi-Agent Formation’s Obstacle Avoidance Problem Based on Three-Dimensional Vectorial Artificial Potential Field Method

2014 ◽  
Vol 596 ◽  
pp. 251-258 ◽  
Author(s):  
Ji Yang Dai ◽  
Lin Fei Yin ◽  
Chen Peng ◽  
Bao Jian Yang ◽  
Cun Song Wang
Keyword(s):  
Obstacle Avoidance ◽  
Potential Field ◽  
Three Dimensional ◽  
Field Method ◽  
Artificial Potential Field ◽  
Potential Field Method ◽  
Pyramid Structure ◽  
Multi Agent ◽  
Artificial Potential Field Method ◽  
Avoidance Problem

In order to solve the obstacle avoidance problem when the Multi-Agent formation get through the area full of obstacles, improved the traditional Artificial Potential Field method, add the vectorial information to the agent’s model, presented the Three-Dimensional Vectorial Artificial Potential Field method (TDVAPF). Firstly, improved the model of agent, obstacle and target; then, improved the Multi-Agent formation motion model, the Multi-Agent formation’s structure is “pyramid” structure; Finally, improved the agent’s force, add the “rotational force” to the agent’s force, it makes agent avoid the “local trouble”. The numerical simulation verified the correctness and effectiveness of the TDVAPF method in Multi-Agent formation’s obstacle avoidance problem.

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