The Motion Analysis And Simulation Of Flapping Flight

This thesis mainly studies on the observation and motion parameters reconstruction of flap-ping flight,the stability analysis of insects hovering,and the flapping mechanisms design for the PIV experiments,aiming to improve the existing hull reconstruction and pose estimation algo-rithms,propose the analysis method of insect hovering under the active control under varying flapping frequency,and design flapping mechanisms with multiple freedoms for PIV experiments to implement more fined motion.As for hull reconstruction and pose estimation,the thesis reconstruct the hull of insect under the assumption that the insect body is rigid and its section is elliptical with the data of body radius,centerline and the wing outline.A pose estimation method is proposed,which is to obtain the rough voxel set from the images firstly to estimate the initial pose,then perform fine search with the hull projections to obtain best pose match.As for the insect hovering stability,the quasi-steady model and blade element method are used in this thesis to analyze the aerodynamics of hovering insect.Then the averaging theory is applied to obtain averaged aerodynamic forces after the original dynamic system is transformed into new dynamics,and the perturbation equation is derivated from the small perturbation theory.Finally the stability analysis is conducted based on the Routh-Hurwitz stability criterion.As for the experimental flapping motion system design,this thesis analyzes the design principles and keeps the Reynolds number and Strouhal number same in the real and experimental environment respectively,and describes how to the design bee-like and dragonfly-like flapping mechanisms and how the mechanisms are driven.The control system is introduced at last.Based on the methods above,this thesis conduct hull reconstruction and obtain pose esti-mation result of drone-fly near hovering with open dataset of drone-fly flying,which verifies the algorithm proposed.The result shows that the positional and deviation angles in the insect co-ordinate system share similar characters.As for hovering stability,a hummingbird-like flapping mechanism is designed and the stability of the longitudinal dynamics system under a linear con-troller is discussed with the dynamic and kinematic parameters of red-throated hummingbird,and then feasible stability region of gain selection is given.When designing the flapping mechanisms,the relationship between its size and the flapping frequency and two detailed design schemes are described.The mechanisim parameters and control system configuration are also given.The innovations of this thesis mainly include the improvement of the insects' pose estima-tion method which can conduct estimation more finely,the method proposal for stability analysis under active control by varying flapping frequency and the design of two new types of flapping mechanisms for PIV experiment.