Biomimetics

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23 pages, 7969 KiB

Open AccessArticle

Numerical Simulation of the Advantages of the Figure-Eight Flapping Motion of an Insect on Aerodynamics under Low Reynolds Number Conditions

by Masato Yoshida and Tomohiro Fukui

Biomimetics 2024, 9(4), 249; https://doi.org/10.3390/biomimetics9040249 - 20 Apr 2024

Viewed by 420

Abstract

In proceeding with the advanced development of small unmanned aerial vehicles (UAVs), which are small flying machines, understanding the flight of insects is important because UAVs that use flight are attracting attention. The figure-eight trajectory of the wing tips is often observed in [...] Read more.

In proceeding with the advanced development of small unmanned aerial vehicles (UAVs), which are small flying machines, understanding the flight of insects is important because UAVs that use flight are attracting attention. The figure-eight trajectory of the wing tips is often observed in the flight of insects. In this study, we investigated the more efficient figure-eight motion patterns in generating lift during the hovering motion and the relationship between figure-eight motion and Reynolds number. For this purpose, we compared the ratios of the cycle-averaged lift coefficient to the power coefficient generated from each motion by varying the elevation motion angle, which is the rotational motion that represents the figure-eight motion, and the Reynolds number. The result showed that the motion with a smaller initial phase of the elevation motion angle (

φ_{e 0} \leq 90 °

) could generate lift more efficiently at all Reynolds numbers. In addition, the figure-eight motion was more effective when the Reynolds number was low. Full article

(This article belongs to the Special Issue Bio-Inspired Design and Control of Unmanned Aerial Vehicles (UAVs))

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19 pages, 2765 KiB

Open AccessArticle

A Photosensitivity-Enhanced Plant Growth Algorithm for UAV Path Planning

by Renjie Yang, Pan Huang, Hui Gao, Qingyang Qin, Tao Guo, Yongchao Wang and Yaoming Zhou

Biomimetics 2024, 9(4), 212; https://doi.org/10.3390/biomimetics9040212 - 31 Mar 2024

Viewed by 649

Abstract

With the rise and development of autonomy and intelligence technologies, UAVs will have increasingly significant applications in the future. It is very important to solve the problem of low-altitude penetration of UAVs to protect national territorial security. Based on an S-57 electronic chart [...] Read more.

With the rise and development of autonomy and intelligence technologies, UAVs will have increasingly significant applications in the future. It is very important to solve the problem of low-altitude penetration of UAVs to protect national territorial security. Based on an S-57 electronic chart file, the land, island, and threat information for an actual combat environment is parsed, extracted, and rasterized to construct a marine combat environment for UAV flight simulation. To address the problem of path planning for low-altitude penetration in complex environments, a photosensitivity-enhanced plant growth algorithm (PEPG) is proposed. Based on the plant growth path planning algorithm (PGPP), the proposed algorithm improves upon the light intensity preprocessing and light intensity calculation methods. Moreover, the kinematic constraints of the UAV, such as the turning angle, are also considered. The planned path that meets the safety flight requirements of the UAV is smoother than that of the original algorithm, and the length is reduced by at least 8.2%. Finally, simulation tests are carried out with three common path planning algorithms, namely, A*, RRT, and GA. The results show that the PEPG algorithm is superior to the other three algorithms in terms of the path length and path quality, and the feasibility and safety of the path are verified via the autonomous tracking flight of a UAV. Full article

(This article belongs to the Special Issue Bio-Inspired Design and Control of Unmanned Aerial Vehicles (UAVs))

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28 pages, 15339 KiB

Open AccessArticle

Aerodynamic/Hydrodynamic Investigation of Water Cross-Over for a Bionic Unmanned Aquatic–Aerial Amphibious Vehicle

by Wenbiao Gan, Zhenjie Zuo, Junjie Zhuang, Dawei Bie and Jinwu Xiang

Biomimetics 2024, 9(3), 181; https://doi.org/10.3390/biomimetics9030181 - 17 Mar 2024

Viewed by 850

Abstract

An aerodynamic/hydrodynamic investigation of water cross-over is performed for a bionic unmanned aquatic–aerial amphibious vehicle (bionic UAAV). According to flying fish features and UAAV flight requirements of water cross-over, the bionic conceptual design of crossing over water is described and planned in multiple [...] Read more.

An aerodynamic/hydrodynamic investigation of water cross-over is performed for a bionic unmanned aquatic–aerial amphibious vehicle (bionic UAAV). According to flying fish features and UAAV flight requirements of water cross-over, the bionic conceptual design of crossing over water is described and planned in multiple stages and modes of motion. A solution procedure for the numerical simulation method, based on a modified SST turbulence model and the VOF model, is expressed, and a verification study is presented using a typical case. Longitudinal–lateral numerical simulation analysis investigates the cruise performance underwater and in the air. The numerical simulation and principal experiment verification are conducted for crossing over water and water surface acceleration. The results indicate that the bionic UAAV has an excellent aerodynamic/hydrodynamic performance and variant configuration to adapt to water cross-over. The bionic UAAV has good water and air navigation stability, and the cruise flying lift–drag ratio is greater than 15 at a low Reynolds number. Its pitching moment has the phenomenon of a “water mound” forming and breaking at the water cross-over process. The present method and the bionic variant configuration provide a feasible water cross-over design and analysis strategy for bionic UAAVs. Full article

(This article belongs to the Special Issue Bio-Inspired Design and Control of Unmanned Aerial Vehicles (UAVs))

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18 pages, 516 KiB

Open AccessArticle

Distributed State Estimation for Flapping-Wing Micro Air Vehicles with Information Fusion Correction

by Xianglin Zhang, Mingqiang Luo, Simeng Guo and Zhiyang Cui

Biomimetics 2024, 9(3), 167; https://doi.org/10.3390/biomimetics9030167 - 10 Mar 2024

Viewed by 893

Abstract

In this paper, we explore a nonlinear interactive network system comprising nodalized flapping-wing micro air vehicles (FMAVs) to address the distributed

H_{\infty}

state estimation problem associated with FMAVs. We enhance the model by introducing an information fusion function, leading to an information-fusionized [...] Read more.

In this paper, we explore a nonlinear interactive network system comprising nodalized flapping-wing micro air vehicles (FMAVs) to address the distributed

H_{\infty}

state estimation problem associated with FMAVs. We enhance the model by introducing an information fusion function, leading to an information-fusionized estimator model. This model ensures both estimation accuracy and the completeness of FMAV topological information within a unified framework. To facilitate the analysis, each FMAV’s received signal is individually sampled using independent and time-varying samplers. Transforming the received signals into equivalent bounded time-varying delays through the input delay method yields a more manageable and analyzable time-varying nonlinear network error system. Subsequently, we construct a Lyapunov–Krasovskii functional (LKF) and integrate it with the refined Wirtinger and relaxed integral inequalities to derive design conditions for the FMAVs’ distributed

H_{\infty}

state estimator, minimizing conservatism. Finally, we validate the effectiveness and superiority of the designed estimator through simulations. Full article

(This article belongs to the Special Issue Bio-Inspired Design and Control of Unmanned Aerial Vehicles (UAVs))

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18 pages, 2811 KiB

Open AccessArticle

Multigene and Improved Anti-Collision RRT* Algorithms for Unmanned Aerial Vehicle Task Allocation and Route Planning in an Urban Air Mobility Scenario

by Qiang Zhou, Houze Feng and Yueyang Liu

Biomimetics 2024, 9(3), 125; https://doi.org/10.3390/biomimetics9030125 - 21 Feb 2024

Cited by 1 | Viewed by 1026

Abstract

Compared to terrestrial transportation systems, the expansion of urban traffic into airspace can not only mitigate traffic congestion, but also foster establish eco-friendly transportation networks. Additionally, unmanned aerial vehicle (UAV) task allocation and trajectory planning are essential research topics for an Urban Air [...] Read more.

Compared to terrestrial transportation systems, the expansion of urban traffic into airspace can not only mitigate traffic congestion, but also foster establish eco-friendly transportation networks. Additionally, unmanned aerial vehicle (UAV) task allocation and trajectory planning are essential research topics for an Urban Air Mobility (UAM) scenario. However, heterogeneous tasks, temporary flight restriction zones, physical buildings, and environment prerequisites put forward challenges for the research. In this paper, multigene and improved anti-collision RRT* (IAC-RRT*) algorithms are proposed to address the challenge of task allocation and path planning problems in UAM scenarios by tailoring the chance of crossover and mutation. It is proved that multigene and IAC-RRT* algorithms can effectively minimize energy consumption and tasks’ completion duration of UAVs. Simulation results demonstrate that the strategy of this work surpasses traditional optimization algorithms, i.e., RRT algorithm and gene algorithm, in terms of numerical stability and convergence speed. Full article

(This article belongs to the Special Issue Bio-Inspired Design and Control of Unmanned Aerial Vehicles (UAVs))

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21 pages, 3163 KiB

Open AccessArticle

An Angular Acceleration Based Looming Detector for Moving UAVs

by Jiannan Zhao, Quansheng Xie, Feng Shuang and Shigang Yue

Biomimetics 2024, 9(1), 22; https://doi.org/10.3390/biomimetics9010022 - 02 Jan 2024

Viewed by 1208

Abstract

Visual perception equips unmanned aerial vehicles (UAVs) with increasingly comprehensive and instant environmental perception, rendering it a crucial technology in intelligent UAV obstacle avoidance. However, the rapid movements of UAVs cause significant changes in the field of view, affecting the algorithms’ ability to [...] Read more.

Visual perception equips unmanned aerial vehicles (UAVs) with increasingly comprehensive and instant environmental perception, rendering it a crucial technology in intelligent UAV obstacle avoidance. However, the rapid movements of UAVs cause significant changes in the field of view, affecting the algorithms’ ability to extract the visual features of collisions accurately. As a result, algorithms suffer from a high rate of false alarms and a delay in warning time. During the study of visual field angle curves of different orders, it was found that the peak times of the curves of higher-order information on the angular size of looming objects are linearly related to the time to collision (TTC) and occur before collisions. This discovery implies that encoding higher-order information on the angular size could resolve the issue of response lag. Furthermore, the fact that the image of a looming object adjusts to meet several looming visual cues compared to the background interference implies that integrating various field-of-view characteristics will likely enhance the model’s resistance to motion interference. Therefore, this paper presents a concise A-LGMD model for detecting looming objects. The model is based on image angular acceleration and addresses problems related to imprecise feature extraction and insufficient time series modeling to enhance the model’s ability to rapidly and precisely detect looming objects during the rapid self-motion of UAVs. The model draws inspiration from the lobula giant movement detector (LGMD), which shows high sensitivity to acceleration information. In the proposed model, higher-order information on the angular size is abstracted by the network and fused with multiple visual field angle characteristics to promote the selective response to looming objects. Experiments carried out on synthetic and real-world datasets reveal that the model can efficiently detect the angular acceleration of an image, filter out insignificant background motion, and provide early warnings. These findings indicate that the model could have significant potential in embedded collision detection systems of micro or small UAVs. Full article

(This article belongs to the Special Issue Bio-Inspired Design and Control of Unmanned Aerial Vehicles (UAVs))

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15 pages, 8637 KiB

Open AccessArticle

Computational Study of Aerodynamic Effects of the Dihedral and Angle of Attack of Biomimetic Grids Installed on a Mini UAV

by Rafael Bardera, Ángel Antonio Rodríguez-Sevillano, Estela Barroso Barderas and Juan Carlos Matias Garcia

Biomimetics 2024, 9(1), 12; https://doi.org/10.3390/biomimetics9010012 - 29 Dec 2023

Cited by 1 | Viewed by 1181

Abstract

In this paper, a numerical analysis of a biomimetic unmanned aerial vehicle (UAV) is presented. Its wings feature three grids at the tip similar to the primary feathers of birds in order to modify the lift distribution over the wing and help in [...] Read more.

In this paper, a numerical analysis of a biomimetic unmanned aerial vehicle (UAV) is presented. Its wings feature three grids at the tip similar to the primary feathers of birds in order to modify the lift distribution over the wing and help in reducing the induced drag. Numerical analysis using computational fluid dynamics (CFD) is presented to analyze the aerodynamic effects of the changes in dihedral and angle of attack (with respect of the rest of the wing) of these small grids at the tip. The aerodynamic performances (lift, drag, and efficiency) and rolling capabilities are obtained under different flight conditions. The effects of changing the dihedral are small. However, the change in the grid angle of attack increases aerodynamic efficiency by up to 2.5 times when the UAV is under cruise flight conditions. Changes to the angle of attack of the grids also provide increased capabilities for rolling. Finally, boundary values of the pressure coefficient and non-dimensional velocity contours are presented on the surfaces of the UAV, in order to relate the aerodynamic results to the aerodynamic patterns observed over the wing. Full article

(This article belongs to the Special Issue Bio-Inspired Design and Control of Unmanned Aerial Vehicles (UAVs))

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15 pages, 2519 KiB

Open AccessArticle

Extracting Technicians’ Skills for Human–Machine Collaboration in Aircraft Assembly

by Yaling Tian, Ji Li, Junjie Dan, Yongsheng Shu, Chang Liu, Ruijie Li and Shiyong Liu

Biomimetics 2023, 8(8), 604; https://doi.org/10.3390/biomimetics8080604 - 13 Dec 2023

Viewed by 1089

Abstract

Research on the efficiency and quality issues faced in aircraft assembly was conducted in this article. A new method of human–machine collaborative riveting was proposed, which combined the flexibility of manual collaboration with the precise control of automatic riveting. The research works include: [...] Read more.

Research on the efficiency and quality issues faced in aircraft assembly was conducted in this article. A new method of human–machine collaborative riveting was proposed, which combined the flexibility of manual collaboration with the precise control of automatic riveting. The research works include: (1) a theoretical model of pneumatic hammer riveting was established to clarify the principle and parameters of riveting process. (2) A smart bucking bar was designed to support the data collection and extraction of manual collaborative riveting process. (3) An automatic riveting experimental platform was designed to test the automatic riveting process incorporating the extracted manual riveting process parameters, and further an optimization strategy was proposed for the automatic riveting process. (4) A human–machine collaborative riveting experimental platform was developed to conduct the verification work. Through the theoretical analysis, experimental research, system scheme design, and process parameters optimization, the application and verification of human–machine collaborative assembly technology have been achieved. This technology is expected to be comprehensively promoted in the field of aircraft manufacturing, and for breaking through the current difficulties of low production efficiency and poor assembly quality control. Full article

(This article belongs to the Special Issue Bio-Inspired Design and Control of Unmanned Aerial Vehicles (UAVs))

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