We propose a control moment generator to control the attitude of an insect-like tailless Flapping-wing Micro Air Vehicle （FW-MAV）, where the flapping wings simultaneously produce the flight force and control moments...We propose a control moment generator to control the attitude of an insect-like tailless Flapping-wing Micro Air Vehicle （FW-MAV）, where the flapping wings simultaneously produce the flight force and control moments. The generator tilts the stroke plane of each wing independently to direct the resultant aerodynamic force in the desired direction to ultimately generate pitch and yaw moments. A roll moment is produced by an additional mechanism that shifts the trailing edge, which changes the wing rotation angles of the two flapping wings and produces an asymmetric thrust. Images of the flapping wings are captured with a high-speed camera and clearly show that the FW-MAV can independently change the stroke planes of its two wings. The measured force and moment data prove that the control moment generator produces reasonable pitch and yaw moments by tilting the stroke plane and realizes a roll moment by shifting the position of the trailing edge at the wing root.展开更多
In this study,the aerodynamic performance of flapping wings using a parallel motion was investigated and compared with the insect-like‘‘fan-sweep’’motion,and the effect of adding a slit to the wings was analyzed.F...In this study,the aerodynamic performance of flapping wings using a parallel motion was investigated and compared with the insect-like‘‘fan-sweep’’motion,and the effect of adding a slit to the wings was analyzed.First,numerical simulations were performed to analyze the wing aerodynamics of two flapping motions with equivalent stroke amplitudes over a range of pitching angles based on computational fluid dynamics(CFD).The simulation results indicated that flapping wings with a rapid and short parallel motion achieved better lift and efficiency than those of the fan-sweep motion while maintaining the same aerodynamic characteristics regarding stall delay and leading-edge vortices.For a parallel motion with a pitching angle of 25◦and 100 mm stroke amplitude,the wings generated an average lift of 8.4 gf with a lift-to-drag ratio of 1.06,respectively,which were 1.8%and 26%greater than those of the fan-sweep motion with a corresponding 96◦stroke amplitude.This situation was reversed when the pitching angle and stroke amplitude were increased to 45◦and 144◦for the fan-sweep motion,which was equivalent to the parallel motion with a 150 mm stroke amplitude.The slit effect in the parallel motion was also evaluated,and the CFD results indicated that a slit width of 1 mm(1/50 wing chord)increased the lift of the wing by approximately 27%in the case of the 150 mm stroke amplitude.Further,the slit width slightly influenced the lift and aerodynamic efficiency.展开更多
目的构建适于高通量筛选的激活素受体样激酶4(ALK4),ALK5和ALK7抑制剂的筛选模型。方法利用Bac to Bac昆虫杆状病毒表达系统,构建ALK4激酶结构域(ALK4kd),ALK5kd和ALK7kd及Smad2和Smad3蛋白的病毒表达系统,转染Sf9昆虫细胞,表达目的蛋白...目的构建适于高通量筛选的激活素受体样激酶4(ALK4),ALK5和ALK7抑制剂的筛选模型。方法利用Bac to Bac昆虫杆状病毒表达系统,构建ALK4激酶结构域(ALK4kd),ALK5kd和ALK7kd及Smad2和Smad3蛋白的病毒表达系统,转染Sf9昆虫细胞,表达目的蛋白;通过谷胱甘肽S-转移酶(GST)亲和柱纯化,获得纯化的目的蛋白;分别以纯化的ALK4,ALK5,ALK7激酶片段与纯化的Smad3和ATP构建ALK4,ALK5,ALK7激酶活性测定体系,优化各反应底物浓度及反应条件,建立适于通量化分析的筛选模型;以已知ALK激酶抑制剂SB431542为工具分子,检测其对激酶的抑制活性,确证筛选模型的可靠性。结果经酶切和PCR鉴定,所得重组Bacmid均正确。转染Sf9昆虫细胞后纯化获得相应目的蛋白。经条件优化,反应体系中激酶和底物蛋白Smad3最佳浓度均为10 mg·L^(-1),ATP最佳初始浓度为10 nmol·L^(-1)。所得ALK4,ALK5和ALK7激酶抑制剂筛选体系的Z′因子分别为0.71,0.51和0.74,符合高通量筛选要求。已知SB431542在所建模型上对ALK4kd,ALK5kd和ALK7kd的抑制活性IC50值分别为22,188和91 nmol·L^(-1)。结论成功构建了ALK4,ALK5和ALK7激酶抑制剂的体外筛选模型。展开更多
文摘We propose a control moment generator to control the attitude of an insect-like tailless Flapping-wing Micro Air Vehicle （FW-MAV）, where the flapping wings simultaneously produce the flight force and control moments. The generator tilts the stroke plane of each wing independently to direct the resultant aerodynamic force in the desired direction to ultimately generate pitch and yaw moments. A roll moment is produced by an additional mechanism that shifts the trailing edge, which changes the wing rotation angles of the two flapping wings and produces an asymmetric thrust. Images of the flapping wings are captured with a high-speed camera and clearly show that the FW-MAV can independently change the stroke planes of its two wings. The measured force and moment data prove that the control moment generator produces reasonable pitch and yaw moments by tilting the stroke plane and realizes a roll moment by shifting the position of the trailing edge at the wing root.
基金funding organizations in China:the National Key Research and Development Program of China(Grant No.2018YFB1305400)the National Natural Science Foundation of China(Grant Nos.62173212 and 11972079).
文摘In this study,the aerodynamic performance of flapping wings using a parallel motion was investigated and compared with the insect-like‘‘fan-sweep’’motion,and the effect of adding a slit to the wings was analyzed.First,numerical simulations were performed to analyze the wing aerodynamics of two flapping motions with equivalent stroke amplitudes over a range of pitching angles based on computational fluid dynamics(CFD).The simulation results indicated that flapping wings with a rapid and short parallel motion achieved better lift and efficiency than those of the fan-sweep motion while maintaining the same aerodynamic characteristics regarding stall delay and leading-edge vortices.For a parallel motion with a pitching angle of 25◦and 100 mm stroke amplitude,the wings generated an average lift of 8.4 gf with a lift-to-drag ratio of 1.06,respectively,which were 1.8%and 26%greater than those of the fan-sweep motion with a corresponding 96◦stroke amplitude.This situation was reversed when the pitching angle and stroke amplitude were increased to 45◦and 144◦for the fan-sweep motion,which was equivalent to the parallel motion with a 150 mm stroke amplitude.The slit effect in the parallel motion was also evaluated,and the CFD results indicated that a slit width of 1 mm(1/50 wing chord)increased the lift of the wing by approximately 27%in the case of the 150 mm stroke amplitude.Further,the slit width slightly influenced the lift and aerodynamic efficiency.
