To calculate the aerodynamics of flapping-wing micro air vehicle（MAV） with the high efficiency and the engineering-oriented accuracy,an improved unsteady vortex lattice method （UVLM） for MAV is proposed. The metho...To calculate the aerodynamics of flapping-wing micro air vehicle（MAV） with the high efficiency and the engineering-oriented accuracy,an improved unsteady vortex lattice method （UVLM） for MAV is proposed. The method considers the influence of instantaneous wing deforming in flapping,as well as the induced drag,additionally models the stretching and the dissipation of vortex rings,and can present the aerodynamics status on the wing surface. An implementation of the method is developed. Moreover,the results and the efficiency of the proposed method are verified by CFD methods. Considering the less time cost of UVLM,for application of UVLM in the MAV optimization,the influence of wake vortex ignoring time saving and precision is studied. Results show that saving in CPU time with wake vortex ignoring the appropriate distance is considerable while the precision is not significantly reduced. It indicates the potential value of UVLM in the optimization of MAV design.展开更多
Using the method of structural finite element topology optimization and analysis of the hindwings of Trypoxylus dichotomus,this work identified the main loading force transmission path and designed the initial structu...Using the method of structural finite element topology optimization and analysis of the hindwings of Trypoxylus dichotomus,this work identified the main loading force transmission path and designed the initial structure of a bionic flexible wing.A structural design scheme of the vibration damping unit was proposed,and the structural mechanics and modal vibration characteristics were simulated and analyzed.3D printing technology was used to manufacture the designed bionic wing skeleton,which was combined with two kinds of wing membrane materials.The Flapping Wing Micro-aerial Vehicle(FWMAV)transmission mechanism vibration characteristics were observed and analyzed by a high-speed digital camera.A triaxial force transducer was used to record the force vibration of the flexible bionic wing flapping in a wind tunnel.A wavelet processing method was used to process and analyze the force signal.The results showed that the force amplitude was more stable,the waveform roughness was the lowest,and the peak shaving phenomenon at the z-axis was the least obvious for the bionic flexible wing model that combined the topology-optimized bionic wing skeleton with a polyamide elastic membrane.This was determined to be the most suitable design scheme for the wings of FWMAVs.展开更多
Birds in nature exhibit excellent long-distance flight capabilities through formation flight,which could reduce energy consumption and improve flight efficiency.Inspired by the biological habits of birds,this paper pr...Birds in nature exhibit excellent long-distance flight capabilities through formation flight,which could reduce energy consumption and improve flight efficiency.Inspired by the biological habits of birds,this paper proposes an autonomous formation flight control method for Large-sized Flapping-Wing Flying Robots(LFWFRs),which can enhance their search range and flight efficiency.First,the kinematics model for LFWFRs is established.Then,an autonomous flight controller based on this model is designed,which has multiple flight control modes,including attitude stabilization,course keeping,hovering,and so on.Second,a formation flight control method is proposed based on the leader–follower strategy and periodic characteristics of flapping-wing flight.The up and down fluctuation of the fuselage of each LFWFR during wing flapping is considered in the control algorithm to keep the relative distance,which overcomes the trajectory divergence caused by sensor delay and fuselage fluctuation.Third,typical formation flight modes are realized,including straight formation,circular formation,and switching formation.Finally,the outdoor formation flight experiment is carried out,and the proposed autonomous formation flight control method is verified in real environment.展开更多
Inspired by large and medium-sized birds,two kinds of flapping-wing flying robots with wingspans beyond 2 meters were developed.They have the appearance of a hawk and a phoenix respectively,so they are called HIT-Hawk...Inspired by large and medium-sized birds,two kinds of flapping-wing flying robots with wingspans beyond 2 meters were developed.They have the appearance of a hawk and a phoenix respectively,so they are called HIT-Hawk and HIT-Phoenix.In this paper,the bionic concept,theoretical analysis,design and manufacturing are introduced in detail.Firstly,the flight principle and characteristics of large and medium-sized birds were summarized.Then,the aerodynamics was modeled based on the thin airfoil theory,and the main design basis was established.Secondly,the mechanical structures of HIT-Hawk and HIT-Phoenix were designed to ensure the lateral and longitudinal stability and have optimized flight performance.Moreover,an autonomous flight control method was proposed and realized in highly integrated on-onboard controller;it satisfies the strict restrictions on mass,size,power and shape.Finally,the prototypes were fabricated and verified through practical flight experiments.The wingspans of these two flapping wing aircrafts are 2.0 m and 2.3 m respectively,the take-off weights are 1.15 kg and 0.86 kg,and the maximum stable endurance is 65 min(with battery of 3S LiPo,4300 mAh)and 8 min(with battery of 3S LiPo,800 mAh).Their wind resistance can both reach level 4.Compared with the small and micro flapping-wing aerial vehicles that mimic insects or small birds,they both have strong load capacity,strong wind resistance and long endurance.展开更多
Flapping-Wing Micro-Air Vehicles are likely to suffer from airflow perturbations.They can mimic the wing modulation of insects in airflow perturbations.However,our knowledge of wing modulation of insects to airflow pe...Flapping-Wing Micro-Air Vehicles are likely to suffer from airflow perturbations.They can mimic the wing modulation of insects in airflow perturbations.However,our knowledge of wing modulation of insects to airflow perturbations remains limited.Here,we subjected hoverflies to headwind and lateral gust perturbations and filmed their wing motions.Then,computational fluid dynamics was employed to estimate the effects of hoverflies’wing kinematic modulations.We also clipped off the antennae of hoverflies to test whether the wing kinematic modulations were different.Results show that hoverflies increase the mean positional angle and modulate the deviation angle to make the wing tip paths of upstroke and downstroke close to compensate for the pitch moment perturbations in the headwind gust.Hoverflies employ asymmetric responses in positional angle in the lateral gust.The stroke amplitude of the left(right)wing increases(decreases)and the mean positional angle of the left(right)wing decreases(increases)during the right lateral gust.Antennae have little effect on the wing kinematic modulations in the lateral gust.These asymmetric responses produce a roll moment,tilting the body to resist the side force generated by the gust.This is a typical helicopter model employed by hoverflies to alleviate the gust.These results provide insight into the remarkable capacity of hoverflies to contend with gusts and can also inspire the design of flapping-wing micro-air vehicles.展开更多
The development of biomimetic aerial robots has emerged as a new solution for studying the flight mechanisms of flying creatures.This study designs a biomimetic robotic butterfly steered via a mass shift mechanism nam...The development of biomimetic aerial robots has emerged as a new solution for studying the flight mechanisms of flying creatures.This study designs a biomimetic robotic butterfly steered via a mass shift mechanism named USTButterfly-II and investigates its flight characteristics using an optical tracking facility.First,a planar fourbar linkage was used to drive the flapping of the designed butterfly-like artificial wings.Next,an innovative tailless steering control method was proposed based on a mass shift mechanism.Finally,the wing kinematics and motion trajectory of the USTButterfly-II were measured using a multi-camera motion capture system,and some difficult-to-measure flapping aerodynamic parameters,such as the instantaneous net lift and thrust coefficients,were determined.These findings present a novel experimental framework that not only provides effective data support for the design and improvement of the robotic butterfly but also benefits the study of biological butterfly flight mechanisms.展开更多
基金Supported by the Aviation Science Foundation of China (2007ZA56001)the National Natural Science Foundation of China(50865009)~~
文摘To calculate the aerodynamics of flapping-wing micro air vehicle（MAV） with the high efficiency and the engineering-oriented accuracy,an improved unsteady vortex lattice method （UVLM） for MAV is proposed. The method considers the influence of instantaneous wing deforming in flapping,as well as the induced drag,additionally models the stretching and the dissipation of vortex rings,and can present the aerodynamics status on the wing surface. An implementation of the method is developed. Moreover,the results and the efficiency of the proposed method are verified by CFD methods. Considering the less time cost of UVLM,for application of UVLM in the MAV optimization,the influence of wake vortex ignoring time saving and precision is studied. Results show that saving in CPU time with wake vortex ignoring the appropriate distance is considerable while the precision is not significantly reduced. It indicates the potential value of UVLM in the optimization of MAV design.
基金supported by the National Natural Science Foundation of China(grant number 31970454)the Aviation Science Foundation of China(2020Z0740R4001)+1 种基金the Graduate Innovation Fund of Jilin University(2022189)Undergraduate Innovation and Entrepreneurship Training Program Project of Jilin University(S202210183259).
文摘Using the method of structural finite element topology optimization and analysis of the hindwings of Trypoxylus dichotomus,this work identified the main loading force transmission path and designed the initial structure of a bionic flexible wing.A structural design scheme of the vibration damping unit was proposed,and the structural mechanics and modal vibration characteristics were simulated and analyzed.3D printing technology was used to manufacture the designed bionic wing skeleton,which was combined with two kinds of wing membrane materials.The Flapping Wing Micro-aerial Vehicle(FWMAV)transmission mechanism vibration characteristics were observed and analyzed by a high-speed digital camera.A triaxial force transducer was used to record the force vibration of the flexible bionic wing flapping in a wind tunnel.A wavelet processing method was used to process and analyze the force signal.The results showed that the force amplitude was more stable,the waveform roughness was the lowest,and the peak shaving phenomenon at the z-axis was the least obvious for the bionic flexible wing model that combined the topology-optimized bionic wing skeleton with a polyamide elastic membrane.This was determined to be the most suitable design scheme for the wings of FWMAVs.
基金This work was supported in part by the National Natural Science Foundation of China(Grant No.62233001)Shenzhen excellent scientific and technological innovation talent training project(Grant No.RCJC20200714114436040)the Basic Research Program of Shenzhen(Grant No.JCYJ20190806142816524).
文摘Birds in nature exhibit excellent long-distance flight capabilities through formation flight,which could reduce energy consumption and improve flight efficiency.Inspired by the biological habits of birds,this paper proposes an autonomous formation flight control method for Large-sized Flapping-Wing Flying Robots(LFWFRs),which can enhance their search range and flight efficiency.First,the kinematics model for LFWFRs is established.Then,an autonomous flight controller based on this model is designed,which has multiple flight control modes,including attitude stabilization,course keeping,hovering,and so on.Second,a formation flight control method is proposed based on the leader–follower strategy and periodic characteristics of flapping-wing flight.The up and down fluctuation of the fuselage of each LFWFR during wing flapping is considered in the control algorithm to keep the relative distance,which overcomes the trajectory divergence caused by sensor delay and fuselage fluctuation.Third,typical formation flight modes are realized,including straight formation,circular formation,and switching formation.Finally,the outdoor formation flight experiment is carried out,and the proposed autonomous formation flight control method is verified in real environment.
基金supported by the National Natural Science Founda-tion of China(Grant No.U1613227)Guangdong Special Support Pro-gram,China(GrantNo.2017TX04X0071)the Basic Research Pro-gram of Shenzhen,China(JCYJ20180507183610564,JCYJ20190806144416980).
文摘Inspired by large and medium-sized birds,two kinds of flapping-wing flying robots with wingspans beyond 2 meters were developed.They have the appearance of a hawk and a phoenix respectively,so they are called HIT-Hawk and HIT-Phoenix.In this paper,the bionic concept,theoretical analysis,design and manufacturing are introduced in detail.Firstly,the flight principle and characteristics of large and medium-sized birds were summarized.Then,the aerodynamics was modeled based on the thin airfoil theory,and the main design basis was established.Secondly,the mechanical structures of HIT-Hawk and HIT-Phoenix were designed to ensure the lateral and longitudinal stability and have optimized flight performance.Moreover,an autonomous flight control method was proposed and realized in highly integrated on-onboard controller;it satisfies the strict restrictions on mass,size,power and shape.Finally,the prototypes were fabricated and verified through practical flight experiments.The wingspans of these two flapping wing aircrafts are 2.0 m and 2.3 m respectively,the take-off weights are 1.15 kg and 0.86 kg,and the maximum stable endurance is 65 min(with battery of 3S LiPo,4300 mAh)and 8 min(with battery of 3S LiPo,800 mAh).Their wind resistance can both reach level 4.Compared with the small and micro flapping-wing aerial vehicles that mimic insects or small birds,they both have strong load capacity,strong wind resistance and long endurance.
基金This work was supported by a grant from the National Natural Science Foundation of China(11672028).
文摘Flapping-Wing Micro-Air Vehicles are likely to suffer from airflow perturbations.They can mimic the wing modulation of insects in airflow perturbations.However,our knowledge of wing modulation of insects to airflow perturbations remains limited.Here,we subjected hoverflies to headwind and lateral gust perturbations and filmed their wing motions.Then,computational fluid dynamics was employed to estimate the effects of hoverflies’wing kinematic modulations.We also clipped off the antennae of hoverflies to test whether the wing kinematic modulations were different.Results show that hoverflies increase the mean positional angle and modulate the deviation angle to make the wing tip paths of upstroke and downstroke close to compensate for the pitch moment perturbations in the headwind gust.Hoverflies employ asymmetric responses in positional angle in the lateral gust.The stroke amplitude of the left(right)wing increases(decreases)and the mean positional angle of the left(right)wing decreases(increases)during the right lateral gust.Antennae have little effect on the wing kinematic modulations in the lateral gust.These asymmetric responses produce a roll moment,tilting the body to resist the side force generated by the gust.This is a typical helicopter model employed by hoverflies to alleviate the gust.These results provide insight into the remarkable capacity of hoverflies to contend with gusts and can also inspire the design of flapping-wing micro-air vehicles.
基金supported by the National Natural Science Foundation of China(62225304,61933001,and 62173031)the Beijing Municipal Natural Science Foundation,China(JQ20026)the Beijing Top Discipline for Artificial Intelligent Science and Engineering,University of Science and Technology Beijing,China.
文摘The development of biomimetic aerial robots has emerged as a new solution for studying the flight mechanisms of flying creatures.This study designs a biomimetic robotic butterfly steered via a mass shift mechanism named USTButterfly-II and investigates its flight characteristics using an optical tracking facility.First,a planar fourbar linkage was used to drive the flapping of the designed butterfly-like artificial wings.Next,an innovative tailless steering control method was proposed based on a mass shift mechanism.Finally,the wing kinematics and motion trajectory of the USTButterfly-II were measured using a multi-camera motion capture system,and some difficult-to-measure flapping aerodynamic parameters,such as the instantaneous net lift and thrust coefficients,were determined.These findings present a novel experimental framework that not only provides effective data support for the design and improvement of the robotic butterfly but also benefits the study of biological butterfly flight mechanisms.
