Flapping-wing rotor(FWR)is an innovative bio-inspired micro aerial vehicle capable of vertical take-off and landing.This unique design combines active flapping motion and passive wing rotation around a vertical centra...Flapping-wing rotor(FWR)is an innovative bio-inspired micro aerial vehicle capable of vertical take-off and landing.This unique design combines active flapping motion and passive wing rotation around a vertical central shaft to enhance aerodynamic performance.The research on FWR,though relatively new,has contributed to 6%of core journal publications in the micro aerial vehicle field over the past two decades.This paper presents the first comprehensive review of FWR,analysing the current state of the art,key advances,challenges,and future research directions.The review highlights FWR’s distinctive kinematics and aerodynamic superiority compared to traditional flapping wings,fixed wings,and rotary wings,discussing recent breakthroughs in efficient,passive wing pitching and asymmetric stroke amplitude for lift enhancement.Recent experiments and remote-controlled take-off and hovering tests of single and dual-motor FWR models have showcased their effectiveness.The review compares FWR flight performance with well-developed insect-like flapping-wing micro aerial vehicles as the technology readiness level progresses from laboratory to outdoor flight testing,advancing from the initial flight of a 2.6 g prototype to the current free flight of a 60-gram model.The review also presents ongoing research in bionic flexible wing structures,flight stability and control,and transitioning between hovering and cruise flight modes for an FWR,setting the stage for potential applications.展开更多
This paper studies the trajectory tracking problem of flapping-wing micro aerial vehicles(FWMAVs)in the longitudinal plane.First of all,the kinematics and dynamics of the FWMAV are established,wherein the aerodynamic ...This paper studies the trajectory tracking problem of flapping-wing micro aerial vehicles(FWMAVs)in the longitudinal plane.First of all,the kinematics and dynamics of the FWMAV are established,wherein the aerodynamic force and torque generated by flapping wings and the tail wing are explicitly formulated with respect to the flapping frequency of the wings and the degree of tail wing inclination.To achieve autonomous tracking,an adaptive control scheme is proposed under the hierarchical framework.Specifically,a bounded position controller with hyperbolic tangent functions is designed to produce the desired aerodynamic force,and a pitch command is extracted from the designed position controller.Next,an adaptive attitude controller is designed to track the extracted pitch command,where a radial basis function neural network is introduced to approximate the unknown aerodynamic perturbation torque.Finally,the flapping frequency of the wings and the degree of tail wing inclination are calculated from the designed position and attitude controllers,respectively.In terms of Lyapunov's direct method,it is shown that the tracking errors are bounded and ultimately converge to a small neighborhood around the origin.Simulations are carried out to verify the effectiveness of the proposed control scheme.展开更多
A three-wing Flapping Wing Rotor Micro Aerial Vehicle(FWR-MAV)which can perform controlled flight is introduced and an experimental study on this vehicle is presented.A mechanically driven flapping rotary mechanism is...A three-wing Flapping Wing Rotor Micro Aerial Vehicle(FWR-MAV)which can perform controlled flight is introduced and an experimental study on this vehicle is presented.A mechanically driven flapping rotary mechanism is designed to drive the three flapping wings and generate lift,and control mechanisms are designed to control the pose of the FWR-MAV.A flight control board for attitude control with robust onboard attitude estimation and a control algorithm is also developed to perform stable hovering flight and forward flight.A series of flight tests was conducted,with hovering flight and forward flight tests performed to optimize the control parameters and assess the performance of the FWR-MAV.The hovering flight test shows the ability of the FWR-MAV to counteract the moment generated by rotary motion and maintain the attitude of the FWR-MAV in space;the experiment of forward flight shows that the FWR-MAV can track the desired attitude.展开更多
Topology optimization is an effective method to obtain a lightweight structure that meets the requirements of structural strength.Whether the optimization results meet the actual needs mainly depends on the accuracy o...Topology optimization is an effective method to obtain a lightweight structure that meets the requirements of structural strength.Whether the optimization results meet the actual needs mainly depends on the accuracy of the material properties and the boundary conditions,especially for a tiny Flapping-wing Micro Aerial Vehicle(FMAV)transmission system manufactured by 3D printing.In this paper,experimental and numerical computation efforts were undertaken to gain a reliable topology optimization method for the bottom of the transmission system.First,the constitutive behavior of the ultraviolet(UV)curable resin used in fabrication was evaluated.Second,a numerical computation model describing further verified via experiments.Topology optimization modeling considering nonlinear factors,e.g.contact,friction and collision,was presented,and the optimization results were verified by both dynamic simulation and experiments.Finally,detailed discussions on different load cases and constraints were presented to clarify their effect on the optimization.Our methods and results presented in this paper may shed light on the lightweight design of a FMAV.展开更多
The 3D model of flapping wing mechanism and veins is constructed in 3D computer aided design (CAD) software UG.Then the co-simulation model is established by using multibody dynamics software ADAMS and MATLAB.The vali...The 3D model of flapping wing mechanism and veins is constructed in 3D computer aided design (CAD) software UG.Then the co-simulation model is established by using multibody dynamics software ADAMS and MATLAB.The validation of this co-simulation model is verified by comparing the simulation results with final experiments.The simulation results and experiments reveal that the relation between flapping frequency and driving voltage of motor is approximately linear under various wingspans.The variance of flapping frequency among different wingspans augments gradually with increasing voltage.Furthermore,the simulation results suggest that flapping frequency is sensitive to wingspan and decreases with increasing wingspan of veins,and the relation between flapping frequency and moment of inertia of veins is also approximately linear for various voltages.展开更多
Hovering ability forms the basis for space operations of Micro Aerial Vehicles(MAVs).The problem of uneven load puts high demands on the wing design.In this paper,a new hovering-mode for MAVs,inspired by flapping flig...Hovering ability forms the basis for space operations of Micro Aerial Vehicles(MAVs).The problem of uneven load puts high demands on the wing design.In this paper,a new hovering-mode for MAVs,inspired by flapping flight in bees and hummingbirds but using high-aspect-ratio and low-stress wings,is proposed.Different from the flapping actuations that occur at the wing roots,the two wings are driven back and forth in a straight line.To simplify the design and control the angle of attack,passive wing rotation is employed.The numerical results and analysis show that the maximum stress of the oscillating wing is approximately 1/6 of that of the flapping wing when the lift of the oscillating wing is twice that of the flapping wing.A theoretical aerodynamic model of the kinematics of the vehicle's driving mechanism was developed to fulfill its design.Force measurements indicate that the vehicle generates a sufficiently high cycle-averaged vertical thrust(71 g)for liftoff at a maximum frequency of 5.56 Hz,thereby validating the proposed aerodynamic model.Moreover,liftoff performance is presented to visually demonstrate the vertical take-off capabilities and hovering potential of the aeromechanical solution.展开更多
The overall hardware construction of autopilot within micro aerial vehicle is presented. The boot process of VxWorks real time operating system as well as the conception and function of board support package （BSP） i...The overall hardware construction of autopilot within micro aerial vehicle is presented. The boot process of VxWorks real time operating system as well as the conception and function of board support package （BSP） is described. And the transplantation process of the VxWroks operat ing system into the hardware platform mentioned above is highlighted. It is shown from the final re sults that VxWorks has high stability and real time performance, ensuring accurate flight control and a smooth flight of the micro aerial vehicle.展开更多
In the context of improved navigation for micro aerial vehicles,a new scene recognition visual descriptor,called spatial color gist wavelet descriptor(SCGWD),is proposed.SCGWD was developed by combining proposed Ohta ...In the context of improved navigation for micro aerial vehicles,a new scene recognition visual descriptor,called spatial color gist wavelet descriptor(SCGWD),is proposed.SCGWD was developed by combining proposed Ohta color-GIST wavelet descriptors with census transform histogram(CENTRIST)spatial pyramid representation descriptors for categorizing indoor versus outdoor scenes.A binary and multiclass support vector machine(SVM)classifier with linear and non-linear kernels was used to classify indoor versus outdoor scenes and indoor scenes,respectively.In this paper,we have also discussed the feature extraction methodology of several,state-of-the-art visual descriptors,and four proposed visual descriptors(Ohta color-GIST descriptors,Ohta color-GIST wavelet descriptors,enhanced Ohta color histogram descriptors,and SCGWDs),in terms of experimental perspectives.The proposed enhanced Ohta color histogram descriptors,Ohta color-GIST descriptors,Ohta color-GIST wavelet descriptors,SCGWD,and state-of-the-art visual descriptors were evaluated,using the Indian Institute of Technology Madras Scene Classification Image Database two,an Indoor-Outdoor Dataset,and the Massachusetts Institute of Technology indoor scene classification dataset[(MIT)-67].Experimental results showed that the indoor versus outdoor scene recognition algorithm,employing SVM with SCGWDs,produced the highest classification rates(CRs)—95.48%and 99.82%using radial basis function kernel(RBF)kernel and 95.29%and 99.45%using linear kernel for the IITM SCID2 and Indoor-Outdoor datasets,respectively.The lowest CRs—2.08%and 4.92%,respectively—were obtained when RBF and linear kernels were used with the MIT-67 dataset.In addition,higher CRs,precision,recall,and area under the receiver operating characteristic curve values were obtained for the proposed SCGWDs,in comparison with state-of-the-art visual descriptors.展开更多
This article summarizes our studies on micro flow sensors fabricated on a flexible polyimide circuit board by a low-cost hybrid process of thin-film deposition and circuit printing. The micro flow sensor has merits of...This article summarizes our studies on micro flow sensors fabricated on a flexible polyimide circuit board by a low-cost hybrid process of thin-film deposition and circuit printing. The micro flow sensor has merits of flexibility, structural simplicity, easy integrability with circuits, and good sensing performance. The sensor, which adheres to an object surface, can detect the surface flow around the object. In our study, we install the fabricated micro flow sensors on micro aerial vehicles （MAVs） to detect the surface flow variation around the aircraft wing and deduce the aerodynamic parameters of the MAVs in flight. Wind tunnel experiments using the sensors integrated with the MAVs are also conducted.展开更多
Insect-scale flapping wing aerial robots actuated by piezoelectric materials—known for their high power density and rapid frequency response—have recently garnered increasing attention.However,the limited output dis...Insect-scale flapping wing aerial robots actuated by piezoelectric materials—known for their high power density and rapid frequency response—have recently garnered increasing attention.However,the limited output displacement of piezoelectric actuators results in complex transmission methods that are challenging to assemble.Furthermore,high piezoelectric coefficient materials capable of large displacements for direct wing actuation are fragile,costly,and relatively bulky.This article presents a novel design for minimalist insect-scale aerial robots,where piezoelectric bimorph PZT actuators directly drive two pairs of wings,thus eliminating complex transmission mechanisms and reducing fabrication complexity.These robots demonstrate high liftoff speeds and favorable lift-to-weight ratios,and they can achieve vertical ascent under uncontrolled open-loop conditions.The piezoelectric direct-driven twowing insect-scale aerial robot,based on this approach,features an 8 cm wingspan and a prototype weight of 140 mg,successfully achieving takeoff under unconstrained conditions with an external power source.To further enhance insect-scale aerial robot performance,we optimized the wing-to-actuator ratio and wing arrangement.We propose a biaxial aerial robot with an X-shaped structure,a 2:1 wing-toactuator ratio,a 70 mm wingspan,and a total mass of 160 mg.This structure demonstrates a high lift-to-weight ratio of 2.8:1.During free flight,when powered externally,it attains a maximum takeoff speed exceeding 1 m/s and achieves a vertical takeoff height surpassing 80 cm under uncontrolled conditions.Consequently,it ranks among the fastest prototypes in the milligram-scale weight category.展开更多
During indoor operations,Unmanned Aerial Vehicles(UAVs)are required to embody attributes such as heightened sensitivity,compact design,and robust maneuverability.A high operational advantage is evident when tasks are ...During indoor operations,Unmanned Aerial Vehicles(UAVs)are required to embody attributes such as heightened sensitivity,compact design,and robust maneuverability.A high operational advantage is evident when tasks are executed using multiple UAVs in unison.Despite the prevalent focus in current UAV research on enhancing discrete components or modules,a holistic,integrated approach that encompasses the UAV architecture,platform design,algorithms,simulation,and swarm intelligence,is lacking.This study introduces a micro-UAV swarm system designed for efficient perception within partially known indoor environments.We devised the comprehensive architectural blueprint of a micro-UAV swarm system.A communication routing evaluation metric is proposed to improve the quality of intercommunication among UAVs in the micro-UAV swarm.In addressing the localization and perception challenges,this study features the development of a multisensor-based autonomous positioning methodology,complemented by an object detection and tracking framework based on YOLOv5 and DeepSORT technologies.In the realm of decision making,we used the DuelingDQN algorithm to facilitate mission allocation and scheduling within the micro-UAV swarm system.For flight control,we introduced a control strategy that integrated pipeline control and visual servoing mechanisms.We developed a dedicated simulation platform and designed a realistic scenario to rigorously validate the efficacy of the entire micro-UAV swarm system in simulated exercises and actual flight tests.展开更多
This study investigates the aerodynamic characteristics of a low-Reynolds-number airfoil at high angles of attack(AoA)from 0°to 90°,focusing on their relevance for micro and unmanned aerial vehicle(MAV/UAV)a...This study investigates the aerodynamic characteristics of a low-Reynolds-number airfoil at high angles of attack(AoA)from 0°to 90°,focusing on their relevance for micro and unmanned aerial vehicle(MAV/UAV)applications.Simulations are conducted using the k-ωshear stress transport(SST)turbulence model using ANSYS Fluent software.Among the key findings is that the lift coefficient CL increases from 1.2981 at 0°AoA to a peak of 2.034 at 11°before decreasing to 1.51 at 90°,indicating initial lift improvement followed by a reduction due to potential flow separation or stall.The drag coefficient CD increases from 0.0222 at 0°AoA to a peak of 0.3572 at 12°,and then decreases to 0.0467 at 90°,indicating initially increasing turbulence and separation,followed by stabilization in the flow regime.The lift-to-drag ratio L/D reaches its maximum of 32.334 at 90°AoA,highlighting improved aerodynamic efficiency at higher AoAs despite increased drag.The skin friction coefficient Cf shows a maximum of 0.046918 at the leading edge at 30°AoA and 0.0394262 at the trailing edge at 90°,indicating critical points of frictional drag.Additionally,the turbulence viscosity ratio at the LE peaks at 0.5586 at 30°AoA and drops to 0.004 at 90°,while it increases at the trailing edge,reaching 0.0394262 at 90°,showing heightened turbulence effects at high AoAs.The present numerical study,however,determines the lift coefficient to be 2.00.This yields a maximum percentage variation of 11.5%compared with the value in the literature.These results provide a comprehensive overview of how high-AoA conditions impact aerodynamic performance,offering valuable insights for optimizing airfoil design and improving MAV/UAV efficiency.展开更多
Micro-UAV swarms usually generate massive data when performing tasks. These data can be harnessed with various machine learning(ML) algorithms to improve the swarm’s intelligence. To achieve this goal while protectin...Micro-UAV swarms usually generate massive data when performing tasks. These data can be harnessed with various machine learning(ML) algorithms to improve the swarm’s intelligence. To achieve this goal while protecting swarm data privacy, federated learning(FL) has been proposed as a promising enabling technology. During the model training process of FL, the UAV may face an energy scarcity issue due to the limited battery capacity. Fortunately, this issue is potential to be tackled via simultaneous wireless information and power transfer(SWIPT). However, the integration of SWIPT and FL brings new challenges to the system design that have yet to be addressed, which motivates our work. Specifically,in this paper, we consider a micro-UAV swarm network consisting of one base station(BS) and multiple UAVs, where the BS uses FL to train an ML model over the data collected by the swarm. During training, the BS broadcasts the model and energy simultaneously to the UAVs via SWIPT, and each UAV relies on its harvested and battery-stored energy to train the received model and then upload it to the BS for model aggregation. To improve the learning performance, we formulate a problem of maximizing the percentage of scheduled UAVs by jointly optimizing UAV scheduling and wireless resource allocation. The problem is a challenging mixed integer nonlinear programming problem and is NP-hard in general. By exploiting its special structure property, we develop two algorithms to achieve the optimal and suboptimal solutions, respectively. Numerical results show that the suboptimal algorithm achieves a near-optimal performance under various network setups, and significantly outperforms the existing representative baselines. considered.展开更多
The development of a tailless Flapping Wing Micro Aerial Vehicle(FWMAV)inspired by the hummingbird is presented in this work.By implementing mechanical simplifications,it is possible to use planar machining technology...The development of a tailless Flapping Wing Micro Aerial Vehicle(FWMAV)inspired by the hummingbird is presented in this work.By implementing mechanical simplifications,it is possible to use planar machining technology for manufacturing of the FWMAV’s body,greatly reducing assembly errors.Traditionally,studies on flapping wing aircraft are limited to open-loop wing kinematics control.In this work,an instantaneous closed-loop wing trajectory tracking control system is introduced to minimize wings’trajectory tracking errors.The control system is based on Field-Oriented Control(FOC)with a loop shaping compensation technique near the flapping frequency.Through frequency analysis,the loop shaping compensator ensures the satisfactory bandwidth and performance for the closed-loop flapping system.To implement the proposed controller,a compact autopilot board integrated with FOC hardware is designed,weighing only 2.5 g.By utilizing precise wing trajectory tracking control,the hummingbird-inspired FWMAV demonstrates superior ability to resist external disturbances and exhibits reduced attitude tracking errors during hovering flight compared to the open-loop wing motion.展开更多
Natural flyers have extraordinary flight skills and their prominent aerodynamic performance has attracted a lot of attention.However,the aerodynamic mechanism of birds’flapping wing kinematics still lacks in-depth un...Natural flyers have extraordinary flight skills and their prominent aerodynamic performance has attracted a lot of attention.However,the aerodynamic mechanism of birds’flapping wing kinematics still lacks in-depth understanding.In this paper,the aerodynamic performance of owl-like airfoil undergoing bio-inspired flapping kinematics extracted from a free-flying owl wing has been numerically investigated.The overset mesh technique is used to deal with the large range movements of flapping airfoils.The bio-inspired kinematics consist of plunging and pitching movement.A pure sinusoidal motion and a defined motion composed of plunging of sinusoidal motion and pitching of the bio-inspired kinematics are selected for comparison.The other two NACA airfoils are also selected to figure out the advantages of the owl-like airfoil.It is found that the cambered owl-like airfoil can enhance lift during the downstroke.The bio-inspired kinematics have an obvious advantage in lift generation with a presence of higher peak lift and positive lift over a wider proportion of the flapping cycle.Meanwhile,the bio-inspired motion is more economical for a lower power consumption compared with the sinusoidal motion.The sinusoidal flapping motion is better for thrust generation for a higher peak thrust value in both upstroke and downstroke,while the bio-inspired kinematics mainly generate thrust during the downstroke but produce more drag during the upstroke.The defined motion has similar lift performance with the bio-inspired kinematics,while it consumes more energy and generates less thrust.The unsteady flow field around airfoils is also analyzed to explain the corresponding phenomenon.The research in this paper is helpful to understand the flight mechanism of birds and to design a micro air vehicle with higher performance.展开更多
A novel asymmetrical pitch system for rotary wing is presented. The pitch control characteristics are studied and analyzed. Because elastic linkage is a key part in whole asymmetrical pitch system, in order to obtain ...A novel asymmetrical pitch system for rotary wing is presented. The pitch control characteristics are studied and analyzed. Because elastic linkage is a key part in whole asymmetrical pitch system, in order to obtain the variation of the elastic linkage deformation, an experimental platform mainly based on the device of micro aerial vehicles （MAVs） and a new control system mounted on TMS320LF2407 are designed. This control system has its compacted configuration and reliability. Finally, using this system to control the MAV for simulating the flying forward, experimental results show the MAV＇s flight attitude can he controlled based on the variation of the elastic linkage.展开更多
The Magnus effect is well known phenomena for producing high lift values from spinning symmetrical geometries such as cylinders, spheres, or disks. But, the Magnus force may also be produced by treadmill motion of aer...The Magnus effect is well known phenomena for producing high lift values from spinning symmetrical geometries such as cylinders, spheres, or disks. But, the Magnus force may also be produced by treadmill motion of aerodynamic bodies. To accomplish this, the skin of aerodynamic bodies may circulate with a constant circumferential speed. Here, a novel wing with treadmill motion of skin is introduced which may generate lift at zero air speeds. The new wing may lead to micro aerial vehicle configurations for vertical take-off or landing. To prove the concept, the NACA0015 aerofoil section with circulating skin is computationally investigated. Two cases of stationary air and moving air are studied. It is observed that lift can be generated in stationary air although drag force is also high. For moving air, the lift and drag forces may be adopted between the incidence angles 20° to 25° where lift can posses high values and drag can remain moderate.展开更多
This paper presents a Kalman filter to effectively and economically determine the Euler angles for micro aerial vehicles （MAVs）, whose size and payload are severely limited. The filter uses data from a series of mic...This paper presents a Kalman filter to effectively and economically determine the Euler angles for micro aerial vehicles （MAVs）, whose size and payload are severely limited. The filter uses data from a series of micro-electro mechanical system sensors to determine the selected 3 variables of the direction cosine matrix and the bias of the rate gyro sensors as state elements in a dynamic model, with the gravitational acceleration to build a measurement model. For high speed maneuvers, rigid motion equations are used to correct the measurements of the gravitational acceleration. The filter is designed to automatically tune its gain based on the dynamic system state. Simulations indicate that the Euler angles can be determined with standard deviations less than 3°. The algorithm was successfully implemented in a miniature attitude measurement system suitable for MAVs. Aerobatic flights show that the attitude determination algorithm works effectively. The attitude determination algorithm is effective and economical, and can also be applied to bionic robofishs and land vehicles, whose size and payload are also greatly limited.展开更多
Design and implementation of an effective control mechanism is the key to enable the controlledflight of flapping wing rotor micro aerial vehicles(FWR-MAVs).In order to address this open challenge,in this paper,a trip...Design and implementation of an effective control mechanism is the key to enable the controlledflight of flapping wing rotor micro aerial vehicles(FWR-MAVs).In order to address this open challenge,in this paper,a triple-wing FWR-MAV with its particular control system is proposed.The corresponding experimental study of the vehicle is conducted.As a result,the triple-wing propulsion system demonstrates advantages in both lift generation and flight stability based on the force measurement.The control torques of the proposed FWR-MAV are generated by a particular slipflow rudder mechanism.The effectiveness of such a design combination has been validated experimentally.A series of flight tests are conducted,including sustained hovering and forward-backward maneuvering.To the best of our knowledge,such a design yields the world's first FWR-MAV capable of sustained controlled flight.展开更多
文摘Flapping-wing rotor(FWR)is an innovative bio-inspired micro aerial vehicle capable of vertical take-off and landing.This unique design combines active flapping motion and passive wing rotation around a vertical central shaft to enhance aerodynamic performance.The research on FWR,though relatively new,has contributed to 6%of core journal publications in the micro aerial vehicle field over the past two decades.This paper presents the first comprehensive review of FWR,analysing the current state of the art,key advances,challenges,and future research directions.The review highlights FWR’s distinctive kinematics and aerodynamic superiority compared to traditional flapping wings,fixed wings,and rotary wings,discussing recent breakthroughs in efficient,passive wing pitching and asymmetric stroke amplitude for lift enhancement.Recent experiments and remote-controlled take-off and hovering tests of single and dual-motor FWR models have showcased their effectiveness.The review compares FWR flight performance with well-developed insect-like flapping-wing micro aerial vehicles as the technology readiness level progresses from laboratory to outdoor flight testing,advancing from the initial flight of a 2.6 g prototype to the current free flight of a 60-gram model.The review also presents ongoing research in bionic flexible wing structures,flight stability and control,and transitioning between hovering and cruise flight modes for an FWR,setting the stage for potential applications.
基金supported in part by the National Natural Science Foundation of China(61933001,62061160371)Joint Funds of Equipment Pre-Research and Ministry of Education of China(6141A02033339)Beijing Top Discipline for Artificial Intelligent Science and Engineering,University of Science and Technology Beijing。
文摘This paper studies the trajectory tracking problem of flapping-wing micro aerial vehicles(FWMAVs)in the longitudinal plane.First of all,the kinematics and dynamics of the FWMAV are established,wherein the aerodynamic force and torque generated by flapping wings and the tail wing are explicitly formulated with respect to the flapping frequency of the wings and the degree of tail wing inclination.To achieve autonomous tracking,an adaptive control scheme is proposed under the hierarchical framework.Specifically,a bounded position controller with hyperbolic tangent functions is designed to produce the desired aerodynamic force,and a pitch command is extracted from the designed position controller.Next,an adaptive attitude controller is designed to track the extracted pitch command,where a radial basis function neural network is introduced to approximate the unknown aerodynamic perturbation torque.Finally,the flapping frequency of the wings and the degree of tail wing inclination are calculated from the designed position and attitude controllers,respectively.In terms of Lyapunov's direct method,it is shown that the tracking errors are bounded and ultimately converge to a small neighborhood around the origin.Simulations are carried out to verify the effectiveness of the proposed control scheme.
基金supported by the National Natural Science Foundation of China(No.:11572023)。
文摘A three-wing Flapping Wing Rotor Micro Aerial Vehicle(FWR-MAV)which can perform controlled flight is introduced and an experimental study on this vehicle is presented.A mechanically driven flapping rotary mechanism is designed to drive the three flapping wings and generate lift,and control mechanisms are designed to control the pose of the FWR-MAV.A flight control board for attitude control with robust onboard attitude estimation and a control algorithm is also developed to perform stable hovering flight and forward flight.A series of flight tests was conducted,with hovering flight and forward flight tests performed to optimize the control parameters and assess the performance of the FWR-MAV.The hovering flight test shows the ability of the FWR-MAV to counteract the moment generated by rotary motion and maintain the attitude of the FWR-MAV in space;the experiment of forward flight shows that the FWR-MAV can track the desired attitude.
基金supported by the National Natural Science Foundation of China(No.11672022)。
文摘Topology optimization is an effective method to obtain a lightweight structure that meets the requirements of structural strength.Whether the optimization results meet the actual needs mainly depends on the accuracy of the material properties and the boundary conditions,especially for a tiny Flapping-wing Micro Aerial Vehicle(FMAV)transmission system manufactured by 3D printing.In this paper,experimental and numerical computation efforts were undertaken to gain a reliable topology optimization method for the bottom of the transmission system.First,the constitutive behavior of the ultraviolet(UV)curable resin used in fabrication was evaluated.Second,a numerical computation model describing further verified via experiments.Topology optimization modeling considering nonlinear factors,e.g.contact,friction and collision,was presented,and the optimization results were verified by both dynamic simulation and experiments.Finally,detailed discussions on different load cases and constraints were presented to clarify their effect on the optimization.Our methods and results presented in this paper may shed light on the lightweight design of a FMAV.
基金the National Natural Science Foundationof China(No.60375033)
文摘The 3D model of flapping wing mechanism and veins is constructed in 3D computer aided design (CAD) software UG.Then the co-simulation model is established by using multibody dynamics software ADAMS and MATLAB.The validation of this co-simulation model is verified by comparing the simulation results with final experiments.The simulation results and experiments reveal that the relation between flapping frequency and driving voltage of motor is approximately linear under various wingspans.The variance of flapping frequency among different wingspans augments gradually with increasing voltage.Furthermore,the simulation results suggest that flapping frequency is sensitive to wingspan and decreases with increasing wingspan of veins,and the relation between flapping frequency and moment of inertia of veins is also approximately linear for various voltages.
基金This work was supported by the National Natural Science Foundation of China(No.91960203).
文摘Hovering ability forms the basis for space operations of Micro Aerial Vehicles(MAVs).The problem of uneven load puts high demands on the wing design.In this paper,a new hovering-mode for MAVs,inspired by flapping flight in bees and hummingbirds but using high-aspect-ratio and low-stress wings,is proposed.Different from the flapping actuations that occur at the wing roots,the two wings are driven back and forth in a straight line.To simplify the design and control the angle of attack,passive wing rotation is employed.The numerical results and analysis show that the maximum stress of the oscillating wing is approximately 1/6 of that of the flapping wing when the lift of the oscillating wing is twice that of the flapping wing.A theoretical aerodynamic model of the kinematics of the vehicle's driving mechanism was developed to fulfill its design.Force measurements indicate that the vehicle generates a sufficiently high cycle-averaged vertical thrust(71 g)for liftoff at a maximum frequency of 5.56 Hz,thereby validating the proposed aerodynamic model.Moreover,liftoff performance is presented to visually demonstrate the vertical take-off capabilities and hovering potential of the aeromechanical solution.
基金Supported by the Ministerial Level Foundation(A222006450)
文摘The overall hardware construction of autopilot within micro aerial vehicle is presented. The boot process of VxWorks real time operating system as well as the conception and function of board support package （BSP） is described. And the transplantation process of the VxWroks operat ing system into the hardware platform mentioned above is highlighted. It is shown from the final re sults that VxWorks has high stability and real time performance, ensuring accurate flight control and a smooth flight of the micro aerial vehicle.
文摘In the context of improved navigation for micro aerial vehicles,a new scene recognition visual descriptor,called spatial color gist wavelet descriptor(SCGWD),is proposed.SCGWD was developed by combining proposed Ohta color-GIST wavelet descriptors with census transform histogram(CENTRIST)spatial pyramid representation descriptors for categorizing indoor versus outdoor scenes.A binary and multiclass support vector machine(SVM)classifier with linear and non-linear kernels was used to classify indoor versus outdoor scenes and indoor scenes,respectively.In this paper,we have also discussed the feature extraction methodology of several,state-of-the-art visual descriptors,and four proposed visual descriptors(Ohta color-GIST descriptors,Ohta color-GIST wavelet descriptors,enhanced Ohta color histogram descriptors,and SCGWDs),in terms of experimental perspectives.The proposed enhanced Ohta color histogram descriptors,Ohta color-GIST descriptors,Ohta color-GIST wavelet descriptors,SCGWD,and state-of-the-art visual descriptors were evaluated,using the Indian Institute of Technology Madras Scene Classification Image Database two,an Indoor-Outdoor Dataset,and the Massachusetts Institute of Technology indoor scene classification dataset[(MIT)-67].Experimental results showed that the indoor versus outdoor scene recognition algorithm,employing SVM with SCGWDs,produced the highest classification rates(CRs)—95.48%and 99.82%using radial basis function kernel(RBF)kernel and 95.29%and 99.45%using linear kernel for the IITM SCID2 and Indoor-Outdoor datasets,respectively.The lowest CRs—2.08%and 4.92%,respectively—were obtained when RBF and linear kernels were used with the MIT-67 dataset.In addition,higher CRs,precision,recall,and area under the receiver operating characteristic curve values were obtained for the proposed SCGWDs,in comparison with state-of-the-art visual descriptors.
文摘This article summarizes our studies on micro flow sensors fabricated on a flexible polyimide circuit board by a low-cost hybrid process of thin-film deposition and circuit printing. The micro flow sensor has merits of flexibility, structural simplicity, easy integrability with circuits, and good sensing performance. The sensor, which adheres to an object surface, can detect the surface flow around the object. In our study, we install the fabricated micro flow sensors on micro aerial vehicles （MAVs） to detect the surface flow variation around the aircraft wing and deduce the aerodynamic parameters of the MAVs in flight. Wind tunnel experiments using the sensors integrated with the MAVs are also conducted.
基金supported by the National Natural Science Foundation of China(No.52475039)。
文摘Insect-scale flapping wing aerial robots actuated by piezoelectric materials—known for their high power density and rapid frequency response—have recently garnered increasing attention.However,the limited output displacement of piezoelectric actuators results in complex transmission methods that are challenging to assemble.Furthermore,high piezoelectric coefficient materials capable of large displacements for direct wing actuation are fragile,costly,and relatively bulky.This article presents a novel design for minimalist insect-scale aerial robots,where piezoelectric bimorph PZT actuators directly drive two pairs of wings,thus eliminating complex transmission mechanisms and reducing fabrication complexity.These robots demonstrate high liftoff speeds and favorable lift-to-weight ratios,and they can achieve vertical ascent under uncontrolled open-loop conditions.The piezoelectric direct-driven twowing insect-scale aerial robot,based on this approach,features an 8 cm wingspan and a prototype weight of 140 mg,successfully achieving takeoff under unconstrained conditions with an external power source.To further enhance insect-scale aerial robot performance,we optimized the wing-to-actuator ratio and wing arrangement.We propose a biaxial aerial robot with an X-shaped structure,a 2:1 wing-toactuator ratio,a 70 mm wingspan,and a total mass of 160 mg.This structure demonstrates a high lift-to-weight ratio of 2.8:1.During free flight,when powered externally,it attains a maximum takeoff speed exceeding 1 m/s and achieves a vertical takeoff height surpassing 80 cm under uncontrolled conditions.Consequently,it ranks among the fastest prototypes in the milligram-scale weight category.
基金supported by the National Key R&D Program of China(2024YFB4504500)the Shanghai Collaborative Innovation Project(24xtcx00500).
文摘During indoor operations,Unmanned Aerial Vehicles(UAVs)are required to embody attributes such as heightened sensitivity,compact design,and robust maneuverability.A high operational advantage is evident when tasks are executed using multiple UAVs in unison.Despite the prevalent focus in current UAV research on enhancing discrete components or modules,a holistic,integrated approach that encompasses the UAV architecture,platform design,algorithms,simulation,and swarm intelligence,is lacking.This study introduces a micro-UAV swarm system designed for efficient perception within partially known indoor environments.We devised the comprehensive architectural blueprint of a micro-UAV swarm system.A communication routing evaluation metric is proposed to improve the quality of intercommunication among UAVs in the micro-UAV swarm.In addressing the localization and perception challenges,this study features the development of a multisensor-based autonomous positioning methodology,complemented by an object detection and tracking framework based on YOLOv5 and DeepSORT technologies.In the realm of decision making,we used the DuelingDQN algorithm to facilitate mission allocation and scheduling within the micro-UAV swarm system.For flight control,we introduced a control strategy that integrated pipeline control and visual servoing mechanisms.We developed a dedicated simulation platform and designed a realistic scenario to rigorously validate the efficacy of the entire micro-UAV swarm system in simulated exercises and actual flight tests.
文摘This study investigates the aerodynamic characteristics of a low-Reynolds-number airfoil at high angles of attack(AoA)from 0°to 90°,focusing on their relevance for micro and unmanned aerial vehicle(MAV/UAV)applications.Simulations are conducted using the k-ωshear stress transport(SST)turbulence model using ANSYS Fluent software.Among the key findings is that the lift coefficient CL increases from 1.2981 at 0°AoA to a peak of 2.034 at 11°before decreasing to 1.51 at 90°,indicating initial lift improvement followed by a reduction due to potential flow separation or stall.The drag coefficient CD increases from 0.0222 at 0°AoA to a peak of 0.3572 at 12°,and then decreases to 0.0467 at 90°,indicating initially increasing turbulence and separation,followed by stabilization in the flow regime.The lift-to-drag ratio L/D reaches its maximum of 32.334 at 90°AoA,highlighting improved aerodynamic efficiency at higher AoAs despite increased drag.The skin friction coefficient Cf shows a maximum of 0.046918 at the leading edge at 30°AoA and 0.0394262 at the trailing edge at 90°,indicating critical points of frictional drag.Additionally,the turbulence viscosity ratio at the LE peaks at 0.5586 at 30°AoA and drops to 0.004 at 90°,while it increases at the trailing edge,reaching 0.0394262 at 90°,showing heightened turbulence effects at high AoAs.The present numerical study,however,determines the lift coefficient to be 2.00.This yields a maximum percentage variation of 11.5%compared with the value in the literature.These results provide a comprehensive overview of how high-AoA conditions impact aerodynamic performance,offering valuable insights for optimizing airfoil design and improving MAV/UAV efficiency.
基金supported by the National Natural Science Foundation of China (No. 61971077)the Natural Science Foundation of Chongqing, China (No. cstc2021jcyj-msxmX0458)+3 种基金the open research fund of National Mobile Communications Research Laboratory, Southeast University (No. 2022D06)the Fundamental Research Funds for the Central Universities (No. 2020CDCGTX074)the Natural Science Foundation on Frontier Leading Technology Basic Research Project of Jiangsu (No. BK20212001)the Natural Science Research Project of Jiangsu Higher Education Institutions (No. 21KJB510034)。
文摘Micro-UAV swarms usually generate massive data when performing tasks. These data can be harnessed with various machine learning(ML) algorithms to improve the swarm’s intelligence. To achieve this goal while protecting swarm data privacy, federated learning(FL) has been proposed as a promising enabling technology. During the model training process of FL, the UAV may face an energy scarcity issue due to the limited battery capacity. Fortunately, this issue is potential to be tackled via simultaneous wireless information and power transfer(SWIPT). However, the integration of SWIPT and FL brings new challenges to the system design that have yet to be addressed, which motivates our work. Specifically,in this paper, we consider a micro-UAV swarm network consisting of one base station(BS) and multiple UAVs, where the BS uses FL to train an ML model over the data collected by the swarm. During training, the BS broadcasts the model and energy simultaneously to the UAVs via SWIPT, and each UAV relies on its harvested and battery-stored energy to train the received model and then upload it to the BS for model aggregation. To improve the learning performance, we formulate a problem of maximizing the percentage of scheduled UAVs by jointly optimizing UAV scheduling and wireless resource allocation. The problem is a challenging mixed integer nonlinear programming problem and is NP-hard in general. By exploiting its special structure property, we develop two algorithms to achieve the optimal and suboptimal solutions, respectively. Numerical results show that the suboptimal algorithm achieves a near-optimal performance under various network setups, and significantly outperforms the existing representative baselines. considered.
基金support by the National Natural Science Foundation of China(No.62073217,No.61871266)the Fund of the Ministry of Education of the People’s Republic of China(6141A02022607,6141A020227)the Fund of the Professional Technical Service Platform of Shanghai(19DZ2291103).
文摘The development of a tailless Flapping Wing Micro Aerial Vehicle(FWMAV)inspired by the hummingbird is presented in this work.By implementing mechanical simplifications,it is possible to use planar machining technology for manufacturing of the FWMAV’s body,greatly reducing assembly errors.Traditionally,studies on flapping wing aircraft are limited to open-loop wing kinematics control.In this work,an instantaneous closed-loop wing trajectory tracking control system is introduced to minimize wings’trajectory tracking errors.The control system is based on Field-Oriented Control(FOC)with a loop shaping compensation technique near the flapping frequency.Through frequency analysis,the loop shaping compensator ensures the satisfactory bandwidth and performance for the closed-loop flapping system.To implement the proposed controller,a compact autopilot board integrated with FOC hardware is designed,weighing only 2.5 g.By utilizing precise wing trajectory tracking control,the hummingbird-inspired FWMAV demonstrates superior ability to resist external disturbances and exhibits reduced attitude tracking errors during hovering flight compared to the open-loop wing motion.
基金supported by the National Natural Science Foundation of China(No.11872314 and U1613227)the China Scholarship Council,Key R&D Program in Shaanxi Province of China(No.2020GY-154)Natural Science Basic Research Plan in Shaanxi Province of China(No.2019JQ-394)。
文摘Natural flyers have extraordinary flight skills and their prominent aerodynamic performance has attracted a lot of attention.However,the aerodynamic mechanism of birds’flapping wing kinematics still lacks in-depth understanding.In this paper,the aerodynamic performance of owl-like airfoil undergoing bio-inspired flapping kinematics extracted from a free-flying owl wing has been numerically investigated.The overset mesh technique is used to deal with the large range movements of flapping airfoils.The bio-inspired kinematics consist of plunging and pitching movement.A pure sinusoidal motion and a defined motion composed of plunging of sinusoidal motion and pitching of the bio-inspired kinematics are selected for comparison.The other two NACA airfoils are also selected to figure out the advantages of the owl-like airfoil.It is found that the cambered owl-like airfoil can enhance lift during the downstroke.The bio-inspired kinematics have an obvious advantage in lift generation with a presence of higher peak lift and positive lift over a wider proportion of the flapping cycle.Meanwhile,the bio-inspired motion is more economical for a lower power consumption compared with the sinusoidal motion.The sinusoidal flapping motion is better for thrust generation for a higher peak thrust value in both upstroke and downstroke,while the bio-inspired kinematics mainly generate thrust during the downstroke but produce more drag during the upstroke.The defined motion has similar lift performance with the bio-inspired kinematics,while it consumes more energy and generates less thrust.The unsteady flow field around airfoils is also analyzed to explain the corresponding phenomenon.The research in this paper is helpful to understand the flight mechanism of birds and to design a micro air vehicle with higher performance.
基金supported by the National Natural Science Foundation of China (Grant No.60605028)the National High-Technology Research and Development Program of China (Grant No.2007AA04Z225)+2 种基金the Shanghai Rising-Star Program (Grant Nos.07QA14024, 07QH14006)the Shanghai Shuguang Program (Grant No.07SG47)the Shanghai Leading Key Laboratory of Mechanical Automation and Robotics Science Foundation (Grant No.ZZ0805)
文摘A novel asymmetrical pitch system for rotary wing is presented. The pitch control characteristics are studied and analyzed. Because elastic linkage is a key part in whole asymmetrical pitch system, in order to obtain the variation of the elastic linkage deformation, an experimental platform mainly based on the device of micro aerial vehicles （MAVs） and a new control system mounted on TMS320LF2407 are designed. This control system has its compacted configuration and reliability. Finally, using this system to control the MAV for simulating the flying forward, experimental results show the MAV＇s flight attitude can he controlled based on the variation of the elastic linkage.
文摘The Magnus effect is well known phenomena for producing high lift values from spinning symmetrical geometries such as cylinders, spheres, or disks. But, the Magnus force may also be produced by treadmill motion of aerodynamic bodies. To accomplish this, the skin of aerodynamic bodies may circulate with a constant circumferential speed. Here, a novel wing with treadmill motion of skin is introduced which may generate lift at zero air speeds. The new wing may lead to micro aerial vehicle configurations for vertical take-off or landing. To prove the concept, the NACA0015 aerofoil section with circulating skin is computationally investigated. Two cases of stationary air and moving air are studied. It is observed that lift can be generated in stationary air although drag force is also high. For moving air, the lift and drag forces may be adopted between the incidence angles 20° to 25° where lift can posses high values and drag can remain moderate.
文摘This paper presents a Kalman filter to effectively and economically determine the Euler angles for micro aerial vehicles （MAVs）, whose size and payload are severely limited. The filter uses data from a series of micro-electro mechanical system sensors to determine the selected 3 variables of the direction cosine matrix and the bias of the rate gyro sensors as state elements in a dynamic model, with the gravitational acceleration to build a measurement model. For high speed maneuvers, rigid motion equations are used to correct the measurements of the gravitational acceleration. The filter is designed to automatically tune its gain based on the dynamic system state. Simulations indicate that the Euler angles can be determined with standard deviations less than 3°. The algorithm was successfully implemented in a miniature attitude measurement system suitable for MAVs. Aerobatic flights show that the attitude determination algorithm works effectively. The attitude determination algorithm is effective and economical, and can also be applied to bionic robofishs and land vehicles, whose size and payload are also greatly limited.
基金supported by the National Natural Science Foundation of China(No.11572023).
文摘Design and implementation of an effective control mechanism is the key to enable the controlledflight of flapping wing rotor micro aerial vehicles(FWR-MAVs).In order to address this open challenge,in this paper,a triple-wing FWR-MAV with its particular control system is proposed.The corresponding experimental study of the vehicle is conducted.As a result,the triple-wing propulsion system demonstrates advantages in both lift generation and flight stability based on the force measurement.The control torques of the proposed FWR-MAV are generated by a particular slipflow rudder mechanism.The effectiveness of such a design combination has been validated experimentally.A series of flight tests are conducted,including sustained hovering and forward-backward maneuvering.To the best of our knowledge,such a design yields the world's first FWR-MAV capable of sustained controlled flight.
