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20 pages, 9777 KiB

Open AccessArticle

A New Type Bionic Foldable Wing Design for High Maneuverable Unmanned Aerial Vehicle

by Xitong Zhang, Gui Cheng and Gang Chen

Appl. Sci. 2023, 13(14), 8345; https://doi.org/10.3390/app13148345 - 19 Jul 2023

Cited by 1 | Viewed by 1743

Abstract

With the improvement of aircraft requirements in civil and military fields, aircraft are developing towards the direction of high efficiency and multi-mission. Foldable wing aircraft with large deformation capability will be able to meet flight requirements and performance under different conditions. Based on [...] Read more.

With the improvement of aircraft requirements in civil and military fields, aircraft are developing towards the direction of high efficiency and multi-mission. Foldable wing aircraft with large deformation capability will be able to meet flight requirements and performance under different conditions. Based on the bionic design concept, a feather-like foldable morphing wing based on a multi-link mechanism from the flight characteristics of birds was designed. In order to validate the feasibility of the proposed morphing wing conception, a UAV with bionic foldable wings was fabricated. The aerodynamic performance of the prototype model was tested under different working conditions by wind tunnel test and flight test. The simulation and wind tunnel experimental test showed that the prototype has excellent longitudinal and transverse directional aerodynamics. When the wing is symmetrically morphing, the optimal lift-to-drag ratio can be maintained under different flow velocities. When the wing is asymmetrically morphing, it can replace the aileron to achieve an efficient roll maneuver. Full article

(This article belongs to the Special Issue Bionic Design and Manufacturing of Innovative Aircraft)

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16 pages, 6110 KiB

Open AccessArticle

Hydrophobic Antiwetting of Aquatic UAVs: Static and Dynamic Experiment and Simulation

by Yihua Zheng, Zhimin Huang, Chengchun Zhang and Zhengyang Wu

Appl. Sci. 2022, 12(15), 7626; https://doi.org/10.3390/app12157626 - 28 Jul 2022

Cited by 3 | Viewed by 1548

Abstract

The adhesion of water to the surfaces of unmanned aerial vehicles (UAVs) adversely affects the function. The proposed UAVs will have underwater as well as flight capability, and these aquatic UAVs must shed water to resume flight. The efficient separation of the adhering [...] Read more.

The adhesion of water to the surfaces of unmanned aerial vehicles (UAVs) adversely affects the function. The proposed UAVs will have underwater as well as flight capability, and these aquatic UAVs must shed water to resume flight. The efficient separation of the adhering water from aquatic-UAV surfaces is a challenging problem; we investigated the application of hydrophobic surfaces as a potential solution. Using aquatic-UAV models, one with hydrophilic surfaces and the other with superhydrophobic anisotropic textured surfaces, the antiwetting mechanism of the hydrophobic surfaces was investigated using a simulated-precipitation system and instrumentation to measure the load of the water adhering to the aquatic UAV, and to measure the impact energies. When the model was stationary (passive antiwetting), no adhesion occurred on the superhydrophobic surfaces, while continuous asymmetric thick liquid films were observed on the hydrophilic surfaces. The superhydrophobic surfaces reduced the rain loading by 87.5%. The vibration and movement of the model (dynamic antiwetting, simulating flight motions) accelerated the separation process and reduced the contact time. The observed results were augmented by the use of computational fluid dynamics with lattice Boltzmann methods (LBM) to analyze the particle traces inside the droplets, the liquid phase velocity-field and pressure-field strengths, and the backward bouncing behavior of the derived droplet group induced by the moving surface. The synergy between the superhydrophobic surfaces and the kinetic energy of the droplets promotes the breakup of drops, which avoids the significant lateral unbalance observed with hydrophilic surfaces during simulated flight. Full article

(This article belongs to the Special Issue Bionic Design and Manufacturing of Innovative Aircraft)

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14 pages, 6535 KiB

Open AccessArticle

Analysis of Motion Characteristics of Bionic Morphing Wing Based on Sarrus Linkages

by Zhong Yun, Yunhao Feng, Xiaoyan Tang and Long Chen

Appl. Sci. 2022, 12(12), 6023; https://doi.org/10.3390/app12126023 - 14 Jun 2022

Cited by 4 | Viewed by 2033

Abstract

The variant aircraft can flexibly change its shape to achieve the best sports performance under different flight environments and flight missions. Changing the shape of the wings is a major form of variant aircraft. In this paper, the kingfisher was selected as the [...] Read more.

The variant aircraft can flexibly change its shape to achieve the best sports performance under different flight environments and flight missions. Changing the shape of the wings is a major form of variant aircraft. In this paper, the kingfisher was selected as the bionic object to design a morphing wing. A three-stage lateral folding morphing wing based on Sarrus linkages was presented and applied to the construction of an underwater–aerial transmedia aircraft. The multi-body dynamics method was used to analyze the kinematic characteristics of the morphing wing and to optimize the design of the folding mechanism for the torque values of the hinges between the bottom links. The results showed that the optimized hinge torque value was reduced to 1.2085 N·m, and the lengths of the bottom two links were calculated to be 140 mm and 142 mm, respectively, based on the optimized results. Finally, a series of wing folding and unfolding motion experiments were conducted to prove that the mechanism enabled the span change smoothly, which verified the rationality of the design of this paper. Full article

(This article belongs to the Special Issue Bionic Design and Manufacturing of Innovative Aircraft)

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16 pages, 18570 KiB

Open AccessArticle

Rod–Airfoil Interaction Noise Reduction Using Gradient Distributed Porous Leading Edges

by Yong Wang, Fan Tong, Zhengwu Chen, Chao Wang and Shujie Jiang

Appl. Sci. 2022, 12(10), 4941; https://doi.org/10.3390/app12104941 - 13 May 2022

Cited by 4 | Viewed by 1361

Abstract

Rod–airfoil interaction noise is a major concern in several practical industrial and aeronautical applications. In this study, we constructed bio-inspired gradient distributed porous leading edges to reduce rod–airfoil interaction noise. Noise radiations by NACA 0012 airfoils with nonporous aluminum and porous leading edges [...] Read more.

Rod–airfoil interaction noise is a major concern in several practical industrial and aeronautical applications. In this study, we constructed bio-inspired gradient distributed porous leading edges to reduce rod–airfoil interaction noise. Noise radiations by NACA 0012 airfoils with nonporous aluminum and porous leading edges were experimentally compared in an anechoic wind tunnel by changing the streamwise gap between the upstream rod and the downstream airfoil, as well as the angle of attack of the airfoil. The results of detailed acoustic tests showed that the proposed gradient distributed porous leading edges can significantly reduce noise radiation around and above the peak frequency of the baseline rod–airfoil interaction. Parametric studies on the piecewise porous characteristics showed that rod–airfoil interaction noise reduction is sensitive to the coverage percentage, position, and arrangement order of the porous materials. Porous leading edges with lower pores per inch, larger coverage, and gradually sparse distributed pores better reduced noise. Moreover, the position of the porous material affected the frequency band of noise reduction, and the noise reduction performance was better when it was located in the downstream strips of the porous leading edge. Full article

(This article belongs to the Special Issue Bionic Design and Manufacturing of Innovative Aircraft)

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19 pages, 5826 KiB

Open AccessArticle

Bionic Intelligent Algorithms Used in Helicopter Individual Blade Control Optimization

by Yadong Gao, Dawei Huang, Xinyu Yu and Huaqin Zhang

Appl. Sci. 2022, 12(9), 4392; https://doi.org/10.3390/app12094392 - 27 Apr 2022

Cited by 3 | Viewed by 1543

Abstract

Bionic algorithms are established by imitating human neural structures and animal social behaviors. As an important part of bionic technology, bionic algorithms are often used to solve the control problems of complex nonlinear systems, such as the rotor aeroelasticity dynamics model used in [...] Read more.

Bionic algorithms are established by imitating human neural structures and animal social behaviors. As an important part of bionic technology, bionic algorithms are often used to solve the control problems of complex nonlinear systems, such as the rotor aeroelasticity dynamics model used in the helicopter individual blade control (IBC) optimization process. Two control methods based on bionic intelligent algorithms are introduced, respectively. The first method is to combine the fuzzy neural network and the classical PID control together. Compared with traditional PID control, the combined one was able to adjust the PID control parameters automatically by using the learning ability of the fuzzy neural network. The second method is to directly search the optimal control parameters by using the particle swarm algorithm. Both two methods demonstrate higher efficiency and accuracy; according to the results obtained by the algorithms, the vibration level was 80% less than without the applied high order harmonics. This indicates great application prospects for bionic intelligent algorithms in solving complex nonlinear system problems. Full article

(This article belongs to the Special Issue Bionic Design and Manufacturing of Innovative Aircraft)

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23 pages, 9542 KiB

Open AccessArticle

Aerodynamic Effects of Ceiling and Ground Vicinity on Flapping Wings

by Xueguang Meng, Yinghui Han, Zengshuang Chen, Anas Ghaffar and Gang Chen

Appl. Sci. 2022, 12(8), 4012; https://doi.org/10.3390/app12084012 - 15 Apr 2022

Cited by 6 | Viewed by 1806

Abstract

The combined ceiling and ground effect on the aerodynamics of a hovering flapping wing is investigated using numerical simulations. In the simulations, the wing was located between the ceiling and the ground. Simulations were carried out for different wall clearances at two Reynolds [...] Read more.

The combined ceiling and ground effect on the aerodynamics of a hovering flapping wing is investigated using numerical simulations. In the simulations, the wing was located between the ceiling and the ground. Simulations were carried out for different wall clearances at two Reynolds numbers (

R e

= 10 and 100). Special efforts were paid to whether there exists aerodynamic coupling between the ceiling effect and the ground effect. At

R e

= 10, the combined ceiling and ground effect increases the aerodynamic forces monotonically through two effects, namely the narrow-channel effect and the downwash-reducing effect. Additionally, there exists a coupling effect of the ceiling and the ground for the combined case at

R e

= 10, where the force enhancement of the combined effect is much more significant than the sum of the ceiling-only effect and the ground-only effect. At

R e

= 100, the combined effect of ceiling and ground causes three non-monotonic force regimes (force enhancement, reduction and recovery) with increasing wall clearance. The narrow-channel effect at

R e

= 100 leads to a monotonic force trend, while the downwash-reducing effect results in a non-monotonic force trend. The two effects eventually lead to the three force regimes at

R e

= 100. Unlike the

R e

= 10 case, the coupling effect at

R e

= 100 is small. Full article

(This article belongs to the Special Issue Bionic Design and Manufacturing of Innovative Aircraft)

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23 pages, 8536 KiB

Open AccessArticle

Land–Air–Wall Cross-Domain Robot Based on Gecko Landing Bionic Behavior: System Design, Modeling, and Experiment

by Chengwei Huang, Yong Liu, Ke Wang and Bing Bai

Appl. Sci. 2022, 12(8), 3988; https://doi.org/10.3390/app12083988 - 14 Apr 2022

Cited by 4 | Viewed by 1775

Abstract

Based on the bionic behavior of geckos, this paper presents a land–air–wall cross-domain robot which can fly in air, run on the ground, and adhere to various wall surfaces. When geckos jump and adsorb to vertical surfaces such as trunks, they can still [...] Read more.

Based on the bionic behavior of geckos, this paper presents a land–air–wall cross-domain robot which can fly in air, run on the ground, and adhere to various wall surfaces. When geckos jump and adsorb to vertical surfaces such as trunks, they can still adsorb to the wall with a large contact speed. Inspired by this phenomenon, we analyze the mechanism, apply it to our robot, and optimize the design of the robot structure. In addition, geckos use their tails to adjust posture to achieve abdominal landing during the process of falling. Inspired by this phenomenon, based on the rotor lift/power curve, we optimize the center of gravity by controlling the servo angle. The initial center of gravity offset of the robot is estimated by the extended state observer. The method reduces the distance between the center of gravity and the geometric center, balances the load of each propeller, and finally reduces the total power. The experiment and simulation results validate the feasibility of the land–air–wall cross-domain robot and the bionic methods. Full article

(This article belongs to the Special Issue Bionic Design and Manufacturing of Innovative Aircraft)

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25 pages, 11834 KiB

Open AccessArticle

Structural Design and Parameter Optimization of Bionic Exhaust Tailpipe of Tractors

by Zhenhua Hou, Qigan Wang, Shiqiang Zhang, Tengfei Si, Tiange Li and Zhijun Zhang

Appl. Sci. 2022, 12(5), 2741; https://doi.org/10.3390/app12052741 - 7 Mar 2022

Cited by 4 | Viewed by 1770

Abstract

The exhaust tailpipe of a certain type of tractor was improved from the perspective of bionics, and bionic triangular convex texture was added to the inner surface of the exhaust tailpipe. The bionic tailpipe was proposed to improve noise reduction performance without changing [...] Read more.

The exhaust tailpipe of a certain type of tractor was improved from the perspective of bionics, and bionic triangular convex texture was added to the inner surface of the exhaust tailpipe. The bionic tailpipe was proposed to improve noise reduction performance without changing the overall size parameters of the prototype tailpipe. Acoustics simulation software was used to predict the aeroacoustics noise and transmission loss of the exhaust tailpipe. Bionic exhaust tailpipes with triangular textures of different numbers of circumferential columns, height, and top angles were analyzed to study the noise reduction performance. The results showed that the proposed bionic exhaust tailpipes with triangular convex textures reduced the total sound pressure level and improved the transmission loss of the prototype exhaust tailpipe. To increase the transmission loss, a genetic algorithms (GA) optimized back-propagation neural network (BP) was used to optimize the bionic triangular convex texture parameters. By studying the aerodynamic noise reduction mechanism of bionic tailpipes, the research suggested that a secondary vortex appeared near the bionic texture and reduced aerodynamic drag and aeroacoustics noise. In addition, the sound pressure level amplitude nephogram, velocity vector nephogram, and velocity amplitude nephogram of the exhaust tailpipes were analyzed to study the vibration noise reduction mechanism of the bionic tailpipes. Then, the noise reduction performance was experimentally evaluated. The experimental results of the bionics exhaust tailpipes with triangular convex textures were analyzed and compared to that of the prototype tailpipe. The results demonstrated that the bionic exhaust tailpipes were able to attenuate noise. Full article

(This article belongs to the Special Issue Bionic Design and Manufacturing of Innovative Aircraft)

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20 pages, 5166 KiB

Open AccessArticle

Three-Dimensional Obstacle Avoidance Strategy for Fixed-Wing UAVs Based on Quaternion Method

by Yue Qu and Wenjun Yi

Appl. Sci. 2022, 12(3), 955; https://doi.org/10.3390/app12030955 - 18 Jan 2022

Cited by 5 | Viewed by 1376

Abstract

This work provides a generalization of the three-dimensional velocity obstacle (VO) collision avoidance strategy for nonlinear second-order underactuated systems in three-dimensional dynamic uncertain environments. A hierarchical architecture is exploited to deal with conflicting multiple subtasks, which are defined as several rotations and are [...] Read more.

This work provides a generalization of the three-dimensional velocity obstacle (VO) collision avoidance strategy for nonlinear second-order underactuated systems in three-dimensional dynamic uncertain environments. A hierarchical architecture is exploited to deal with conflicting multiple subtasks, which are defined as several rotations and are parameterized by quaternions. An improved VO method considering the kinodynamic constraints of a class of fixed-wing unmanned aerial vehicles (UAV) is proposed to implement the motion planning. The position error and velocity error can be mapped onto one desired axis so that, only relying on an engine, UAVs can achieve the goal of point tracking without collision. Additionally, the performance of the closed-loop system is demonstrated through a series of simulations performed in a three-dimensional manner. Full article

(This article belongs to the Special Issue Bionic Design and Manufacturing of Innovative Aircraft)

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Review

Jump to: Research

8 pages, 15957 KiB

Open AccessReview

Configuration Design and Trans-Media Control Status of the Hybrid Aerial Underwater Vehicles

by Zongcheng Ma, Danqiang Chen, Guoshuai Li, Xianyong Jing and Shuchen Xiao

Appl. Sci. 2022, 12(2), 765; https://doi.org/10.3390/app12020765 - 13 Jan 2022

Cited by 5 | Viewed by 2316

Abstract

Hybrid aerial underwater vehicles (HAUV) are newly borne vehicle concepts, which could fly in the air, navigate underwater, and cross the air-water surface repeatedly. Although there are many problems to be solved, the advanced concept, which combines the integrated multidomain locomotion of both [...] Read more.

Hybrid aerial underwater vehicles (HAUV) are newly borne vehicle concepts, which could fly in the air, navigate underwater, and cross the air-water surface repeatedly. Although there are many problems to be solved, the advanced concept, which combines the integrated multidomain locomotion of both water and air mediums is worth exploring. This paper presents the water–air trans-media status of the HAUV from the perspective of the configuration and trans-media control. It shows that the multi-rotor HAUV is relatively mature and has achieved a stable water–air trans-media process repeatedly. The morphing HAUV is still in its exploration stage, and has achieved partial success. Full article

(This article belongs to the Special Issue Bionic Design and Manufacturing of Innovative Aircraft)

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