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
Superconducting electrodynamic suspension(EDS)systems generate the required propulsion,levitation,and guidance forces for vehicle motion through electromagnetic interactions between ground coils and onboard supercondu...Superconducting electrodynamic suspension(EDS)systems generate the required propulsion,levitation,and guidance forces for vehicle motion through electromagnetic interactions between ground coils and onboard superconducting coils.The propulsion coils(providing propulsion force)and the null-flux coils(providing levitation and guidance forces)are typically installed separately.In the 1980s,an integrated Propulsion-Levitation-Guidance(PLG)coil was proposed to reduce the number of ground coils and lower system costs,combining all three functional requirements into a single coil design.Visually resembling conventional null-flux coils in appearance,the PLG coils are distinguished by their active three-phase alternating current(AC)exci-tation.However,extensive research and experimental studies revealed that PLG coils exhibit significant pro-pulsion force fluctuations,which not only increase control complexity in the propulsion system but also adversely affect the maintenance of the superconducting state of the superconducting coils.This paper presents an improved PLG system design featuring a double-layer coil configuration,which achieves significant reduction in propulsion force fluctuations without increasing material costs.A comprehensive theoretical model is developed for the fully coupled dynamic circuit,explicitly incorporating mutual inductance coupling between adjacent PLG coils.The model’s validity is rigorously verified through comparison with experimental data ob-tained from the Miyazaki test line.Based on the structural parameters of the PLG coils in the Miyazaki test line,this paper presents the structural parameters of the double-layer PLG coils.Through comparative analysis of the theoretical electromagnetic force characteristics between the two kinds of coil structures,the superior perfor-mance of the double-layer PLG coils is confirmed.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supported in part by the National Key Research and Development Program of China under Grant 2016YFB1200601in part by the Major Project of Advanced Manufacturing and Automation of Changsha Science and Technology Bureau under Grant kq1804037+1 种基金in part by the Youth Independent Innovation Science Fund of National University of Defense Technology under Grant ZN2019-009in part by the Key Project of the National Natural Science Foundation of China under Grant 52241103.
文摘Superconducting electrodynamic suspension(EDS)systems generate the required propulsion,levitation,and guidance forces for vehicle motion through electromagnetic interactions between ground coils and onboard superconducting coils.The propulsion coils(providing propulsion force)and the null-flux coils(providing levitation and guidance forces)are typically installed separately.In the 1980s,an integrated Propulsion-Levitation-Guidance(PLG)coil was proposed to reduce the number of ground coils and lower system costs,combining all three functional requirements into a single coil design.Visually resembling conventional null-flux coils in appearance,the PLG coils are distinguished by their active three-phase alternating current(AC)exci-tation.However,extensive research and experimental studies revealed that PLG coils exhibit significant pro-pulsion force fluctuations,which not only increase control complexity in the propulsion system but also adversely affect the maintenance of the superconducting state of the superconducting coils.This paper presents an improved PLG system design featuring a double-layer coil configuration,which achieves significant reduction in propulsion force fluctuations without increasing material costs.A comprehensive theoretical model is developed for the fully coupled dynamic circuit,explicitly incorporating mutual inductance coupling between adjacent PLG coils.The model’s validity is rigorously verified through comparison with experimental data ob-tained from the Miyazaki test line.Based on the structural parameters of the PLG coils in the Miyazaki test line,this paper presents the structural parameters of the double-layer PLG coils.Through comparative analysis of the theoretical electromagnetic force characteristics between the two kinds of coil structures,the superior perfor-mance of the double-layer PLG coils is confirmed.
