automatic navigation
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Author(s):  
Д.А. Смирнов ◽  
В.Г. Бондарев ◽  
А.В. Николенко

Рассмотрены вопросы разработки системы, способной обеспечивать автоматическую навигацию беспилотного летательного аппарата в окрестности аэродрома без использования дополнительных датчиков. Рассмотрен алгоритм решения этой задачи с использованием бортовой монокулярной системы технического зрения, функционирующей в диапазоне 1,55 мкм. Для обеспечения навигации беспилотный летательный аппарат оснащен системой информационного обмена, а в районе точки взлета-посадки в качестве наземных источников (маяков) предложено использовать полупроводниковые лазеры с некогерентным излучением длиной волны 1,55 мкм, которые обеспечивают работу системы в простых метеоусловиях. Путем измерений угла азимута в двух точках траектории движения беспилотного летательного аппарата вычисляются его координаты местоположения относительно взлетно-посадочной полосы, а также угол курса необходимый для выхода в начальную точку глиссады снижения. Ввиду того, что погрешности измерений обусловлены ошибками измерений угла азимута, курса и скорости полета, ошибками измерения временных интервалов в данной работе пренебрегаем. Полученные графики показывают, что погрешности измерения координат беспилотного летательного аппарата минимальны при пролете напротив маяка и резко возрастают при удалении от него, что обусловлено погрешностью измерения азимута и дальности. При этом измерение местоположения беспилотного летательного аппарата необходимо выполнять на минимальном удалении от маяка The article discusses the development of a system capable of providing automatic navigation of an unmanned aerial vehicle in the vicinity of an airfield without the use of additional sensors. We considered an algorithm for solving this problem using an onboard monocular vision system operating in the range of 1.55 microns. To ensure navigation, the unmanned aerial vehicle is equipped with an information exchange system, and in the area of the take-off and landing point, we propose to use semiconductor lasers with incoherent radiation with a wavelength of 1.55 microns, which ensure the operation of the system in simple weather conditions, as ground sources (beacons). By measuring the azimuth angle at two points of the trajectory of the unmanned aerial vehicle, we calculated its location coordinates relative to the runway, as well as the course angle necessary to reach the starting point of the descent glide path. Since measurement errors are caused by errors in measuring the azimuth angle, course and flight speed, we neglected errors in measuring time intervals in this work. The obtained graphs show that the errors in measuring the coordinates of an unmanned aerial vehicle are minimal when flying in front of the lighthouse and increase sharply when moving away from it, which is due to the error in measuring azimuth and range. At the same time, the measurement of the location of the unmanned aerial vehicle must be carried out at a minimum distance from the lighthouse


2022 ◽  
Vol 2022 ◽  
pp. 1-11
Author(s):  
Hai Tan ◽  
Hao Xu ◽  
Jiguang Dai

Automatic extraction of road information from remote sensing images is widely used in many fields, such as urban planning and automatic navigation. However, due to interference from noise and occlusion, the existing road extraction methods can easily lead to road discontinuity. To solve this problem, a road extraction network with bidirectional spatial information reasoning (BSIRNet) is proposed, in which neighbourhood feature fusion is used to capture spatial context dependencies and expand the receptive field, and an information processing unit with a recurrent neural network structure is used to capture channel dependencies. BSIRNet enhances the connectivity of road information through spatial information reasoning. Using the public Massachusetts road dataset and Wuhan University road dataset, the superiority of the proposed method is verified by comparing its results with those of other models.


2021 ◽  
pp. 265-274
Author(s):  
Zhenguo Zhang ◽  
Jin He ◽  
Hongwen Li ◽  
Qingjie Wang ◽  
Wenchao Yang ◽  
...  

Automatic navigation system for agricultural vehicles have become a widely used technology in precision agriculture over the last few decades. More and more sophisticated tractor control systems, however, revealed that exact positioning of the actual implement is equally or even more important. Based on literature sources and patent databases, the aim of this review is to introduce implement guidance systems and describe its current application in agricultural implement. Agricultural implement guidance is an essential technology for autonomous vehicle operations. In addition, applications and new technologies associated with navigation sensors on passive and active implement guidance are analyzed. Finally, challenges and future perspectives of agricultural implement systems are summarized and forecasted. This study can enrich the application of automatic navigation sensors on agricultural implements and provide a reference for the application of automatic navigation on more field operations.


Author(s):  
Fu Qiang ◽  
Liu Xiang ◽  
Liu Xueyin ◽  
Liao Gonglei

2021 ◽  
Vol 33 (2) ◽  
pp. 371-378
Author(s):  
Masafumi Miwa ◽  
Tsuneo Ushiroda ◽  
◽  

An RTK-GNSS was introduced to realize the precision flight of a drone system for transporting harvested loquats and spraying pesticides to suppress the rotting of fruits. Transportation and spraying experiments were conducted. Precision automatic navigation flights were realized in transportation experiments. In addition, precision landing was performed within approximately 10 cm of the target position. Sufficient spraying flights were performed during the spraying experiment.


Electronics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 466
Author(s):  
Cheng-Hung Chen ◽  
Cheng-Jian Lin ◽  
Shiou-Yun Jeng ◽  
Hsueh-Yi Lin ◽  
Cheng-Yi Yu

This study proposes a knowledge-based neural fuzzy controller (KNFC) for mobile robot navigation control. An effective knowledge-based cultural multi-strategy differential evolution (KCMDE) is used for adjusting the parameters of KNFC. The KNFC is applied in PIONEER 3-DX mobile robots to achieve automatic navigation and obstacle avoidance capabilities. A novel escape approach is proposed to enable robots to autonomously avoid special environments. The angle between the obstacle and robot is used and two thresholds are set to determine whether the robot entries into the special landmarks and to modify the robot behavior for avoiding dead ends. The experimental results show that the proposed KNFC based on the KCMDE algorithm has improved the learning ability and system performance by 15.59% and 79.01%, respectively, compared with the various differential evolution (DE) methods. Finally, the automatic navigation and obstacle avoidance capabilities of robots in unknown environments were verified for achieving the objective of mobile robot control.


2021 ◽  
Vol 37 (5) ◽  
pp. 891-899
Author(s):  
Bingli Zhang ◽  
Jin Cheng ◽  
Pingping Zheng ◽  
Aojia Li ◽  
Xiaoyu Cheng

HighlightsAutomatic navigation technology in autonomous tractors is one of the key technologies in precision agriculture.A path-tracking control algorithm based on lateral deviation and yaw rate feedback is proposed.The modified steering angle was obtained by comparing the ideal yaw rate with the actual yaw rate.The results demonstrate the efficiency and superior accuracy of the proposed algorithm for tractor path-tracking control.Abstract. The performance of path-tracking control systems for autonomous tractors affects the quality and efficiency of farmland operations. The objective of this study was to develop a path-tracking control algorithm based on lateral deviation and yaw rate feedback. The autonomous tractor path lateral dynamics model was developed based on preview theory and a two-degree-of-freedom tractor model. According to the established dynamic model, a path-tracking control algorithm using yaw angular velocity correction was designed, and the ideal steering angle was obtained by lateral deviation and sliding mode control. The modified steering angle was obtained by a proportional-integral-derivative feedback controller after comparing the ideal yaw rate with the actual yaw rate, which was then combined with the ideal steering angle to obtain the desired steering angle. The simulation and experimental results demonstrate the efficiency and superior accuracy of the proposed tractor path-tracking control algorithm, enabling its application in automatic navigation control systems for autonomous tractors. Keywords: Autonomous tractor, Path-tracking control, Sliding mode control, Yaw rate feedback.


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