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
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
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
Flapping Wing Micro Aerial Vehicles(FWMAVs)have caused great concern in various fields because of their high efficiency and maneuverability.Flapping wing motion is a very important factor that affects the performance ...Flapping Wing Micro Aerial Vehicles(FWMAVs)have caused great concern in various fields because of their high efficiency and maneuverability.Flapping wing motion is a very important factor that affects the performance of the aircraft,and previous works have always focused on the time-averaged performance optimization.However,the time-history performance is equally important in the design of motion mechanism and flight control system.In this paper,a time-history performance optimization framework based on deep learning and multi-island genetic algorithm is presented,which is designed in order to obtain the optimal two-dimensional flapping wing motion.Firstly,the training dataset for deep learning neural network is constructed based on a validated computational fluid dynamics method.The aerodynamic surrogate model for flapping wing is obtained after the convergence of training.The surrogate model is tested and proved to be able to accurately and quickly predict the time-history curves of lift,thrust and moment.Secondly,the optimization framework is used to optimize the flapping wing motion in two specific cases,in which the optimized propulsive efficiencies have been improved by over 40%compared with the baselines.Thirdly,a dimensionless parameter C_(variation)is proposed to describe the variation of the time-history characteristics,and it is found that C_(variation)of lift varies significantly even under close time-averaged performances.Considering the importance of time-history performance in practical applications,the optimization that integrates the propulsion efficiency as well as C_(variation)is carried out.The final optimal flapping wing motion balances good time-averaged and time-history performance.展开更多
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 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This work was supported by the specialized research projects of Huanjiang Laboratory,and the Defence Industrial Technology Development Programme,China(Nos.JCKY2019205A006,JCKY2021205B003).
文摘Flapping Wing Micro Aerial Vehicles(FWMAVs)have caused great concern in various fields because of their high efficiency and maneuverability.Flapping wing motion is a very important factor that affects the performance of the aircraft,and previous works have always focused on the time-averaged performance optimization.However,the time-history performance is equally important in the design of motion mechanism and flight control system.In this paper,a time-history performance optimization framework based on deep learning and multi-island genetic algorithm is presented,which is designed in order to obtain the optimal two-dimensional flapping wing motion.Firstly,the training dataset for deep learning neural network is constructed based on a validated computational fluid dynamics method.The aerodynamic surrogate model for flapping wing is obtained after the convergence of training.The surrogate model is tested and proved to be able to accurately and quickly predict the time-history curves of lift,thrust and moment.Secondly,the optimization framework is used to optimize the flapping wing motion in two specific cases,in which the optimized propulsive efficiencies have been improved by over 40%compared with the baselines.Thirdly,a dimensionless parameter C_(variation)is proposed to describe the variation of the time-history characteristics,and it is found that C_(variation)of lift varies significantly even under close time-averaged performances.Considering the importance of time-history performance in practical applications,the optimization that integrates the propulsion efficiency as well as C_(variation)is carried out.The final optimal flapping wing motion balances good time-averaged and time-history performance.
