Reaserch On Flapping And Controrl Mechanism Of Hummingbird-inspired Micro Air Vehicles

The flight mechanism of hummingbird in nature is similar to that of insects.It has excellent flight performance,and can hover in the air,fly upside down,or lift vertically.The flapping wing micro air vehicle(FMAV)uses high-frequency flapping of wings to achieve maneuvering flight.FMAV manifest small size,light weight,high concealment and flexible mobility,which has broad application prospects in the military and civilian fields.A hummingbird-inspired FMAV is developed in this dissertation.Research work is carried out for the flapping and control mechanism of FMAV as follows.First,by studying the morphological parameters and kinematics of the wing,a parametric description of flapping flight is established,which provides theoretical support for the design and optimization of the wing structure.A quasi-steady-state aerodynamic model of flapping flight was established based on unsteady blade element theory.The model has been experimentally verified to effectively estimate the aerodynamic forces generated by the wing of FMAV.Then,considering the requirements of FMAV on mechanism size,weight,structural strength,and stability,a design and manufacturing scheme for a hummingbird-inspired FMAV was proposed.The flapping mechanism was designed to have a high flapping amplitude by using the combination of a crank-rocker and a pulley–string mechanism,which has the characteristics of small size,light weight,and smooth transmission.The control mechanism generates pitch and yaw moments by adjusting the trailing edge.Based on the requirements of bionic wing,the veins have been reasonably arranged so that the wing possess higher strength.The design and manufacture of the FMAV has taken into account the spatial arrangement and assembly relationship of each component.Through the above method,a hummingbird-inspired FMAV is developed in this dissertation,the wingspan is 200 mm,the flapping frequency is 15 Hz,and the flapping angle is 180°,which can generate 8-10 g lift,reaching the weight of the flapping mechanism.Finally,in this dissertation,a three-dimensional motion capture system based on a high-speed camera was established to test the wing kinematics.Based on multi-axis sensors and NI-Labview test platform,force and moment testing is performed.The test verified the applicability of the quasisteady-state aerodynamic model,and completed the investigation of the relationship between the moment generated by the wing and the displacement of the trailing edge.Finally,the stability of the FMAV is effectively improved by adjusting the position of the center of gravity relative to the aerodynamic center estimated by the quasi-steady-state model.In summary,this dissertation designs a hummingbird-inspired FMAV based on the principle of bionics.First,a quasi-direct aerodynamic model of flapping flight is established.Furthermore,a series of researches on the design、fabrication and test of the FMAV was carried out.The work in this dissertation provides theoretical bases,design and fabricate methods for hummingbird-inspired FMAV.