Hovering Aerodynamics Analysis,Optimization Design And Fabrication Of Bio-inspired Flapping Wing Micro Aerial Vehicle

Bio-insect flapping wing micro aerial vehicle(FWMAV)is a kind of centimeter-scale air-flying robot which imitates the flapping-wing motion pattern of fly-ing insects in order to realize flying ability and agile maneuverability similar to flapping-winged flying insects.Because of its future broad application prospects in the field of military and civilian,at present,the development of bio-insect FWMAV has become a hot research topic of some important scientific research institutions and units at home and abroad.In this dissertation,the hovering aerodynamics analysis and optimization design and fabrication of bio-inspired flapping wing micro air vehicle are studied.It includes the following aspects:Firstly,based on the previously reported quasi-steady-state aerodynam-ics model,the authors established an extended quasi-steady-state aerodynamic and inertial force/moment model for the low-Reynolds number unsteady-state aerodynamics of flapping-wing hovering flight.The model is different from the previous model in three points:(1)The aerodynamic damping moment along the chord axis of the wing plane is introduced;(2)the assumption about similar dis-tribution of non-dimensional chordwise centers of pressure for the translational and rotational circulation aerodynamic forces is proposed.This makes the calcu-lation of the rotational moment aerodynamic moment feasible;(3)the calculation about the inertia force and torque arisen from the motion of the wing plane with respect to the center of mass are included.The applicability of the current ex-tended quasi-steady-state aerodynamic and inertial force/moment models is validated and compared with aerodynamic forces and moments measured using the dynamic mechanical scaled fruit flys wing model.Secondly,based on the classical Euler dynamics theory and the above-mentioned extended quasi-steady state model,the complete equations of the two-degree-of-freedom wing-flapping dynamics of flapping-wing hovering flight are established for the first time.Numerical solving algorithms of common non-linear ordinary differential equations,boundary value problem and least squares optimization algorithm are used to solve two-degree-of-freedom highly coupled nonlinear ordinary differential equation(ODEs)for the first time.And the per-fect numerical solutions for these ODEs are successfully obtained.Moreover,a series of driving moments and hinge stiffness coefficient and other design param-eters are also obtained.Thirdly,in order to provide the theoretical optimal wings morphological and kinematic design parameters for bio-insect FWMAV design,the parametriza-tion description of dynamically scaled wing with non-dimensional conformal fea-ture of insect-scale rigid wing is firstly established.And the separate or combined optimizations of wing geometry or/and wing kinematic parameters are systemat-ically performed to minimize the energy of hovering flight,firstly on the basis of-analytically extended quasi-steady aerodynamic model by using hybrid genetic algorithm(Hybrid-GA,which is combined with simplex search).The optimal wings morphological parameters and wing kinematics models are given by the combination optimization results.The optimization results show that the com-bined optimization of wing geometry and kinematic parameters can obtain lower flapping frequency,larger wing geometry parameters and lower power density in comparison with those from other cases of optimization.Moreover,the flapping angle for the optimization involving wing kinematic parameters manifests har-monic shape profile and the pitch angle possesses round trapezoidal profile with certain faster time scale of pitch reversal.The combined optimization framework provides a novel method for the conceptual design of fundamental parameters of-biomimetic flapping wing micro aerial vehicle.Then,in order to estimate the maximum cruise time and range that can be achieved by different weight FW-MAV,the optimization for the wing geometry and kinematic parameters are also executed on basis of the previous combinatorial optimization framework.And a series of combined optimal wings geometry and kinematic design parameters are obtained for the different weight FWMAV when their maximum cruise time and range are achieved under condition of certain advanced ratio or hovering flight.Finally,the design,manufacture and testing of bio-insect FWMAV has been carried out in-depth in this dissertation.For the selected piezoelectric drive bio-insect FWMAV,a flexible hinge is adopted to realize the passive pitch of the wings.In order to design and manufacture the piezoelectric actuators with higher energy density,the static linear model and nonlinear model,dynamic non-linear model for the bimorph cantilever type piezoelectric bending actuators was developed based on the laminar plate theory and the basic mechanics analysis model of the composite mechanics.And the basic parameter prediction and op-timization analysis for piezoelectric bending actuators are carried out.In order to fabricate the components of bio-insect FWMAV powered by the piezoelectric actuators(piezoelectric actuators,compliant dynamics transmissions,artificial wings and fuselage),high-performance piezoelectric ceramics,high-modulus car-bon fiber prepregs and ultra-thin Polymer film(such as polyimide and polyester film)are selected.And the planar intelligent composite micro-structure man-ufacturing technology,UV laser micro-processing and vacuum bag hot-pressing superimposed and hand-assembled micro-assembly process are utilized.After several rounds of iteration design and process improvements,these components were successfully fabricated and assembled to obtain the prototype of bio-insect FWMAV.Moreover,the experimental testing for the output displacement of piezoelectric actuators and wingbeat motion of bio-insect FWMAV have been executed through using simple and crude equipments,the results indicate that the developed prototype can produce large resonance frequency and wingbeat amplitude when it was actuated by the piezoelectric actuator with high output displacement.In summary,the theoretical analysis of the hovering flight aerodynamics,wingbeat dynamics,combinatorial optimization of design parameters of bio-insect FWMAV and the fabrication technology for bio-insect FWMAV provide a ba-sically theoretical framework and viable technology approach for the hovering aerodynamics layout,system-level parameter optimization and prototype design and manufacturing of bio-insect FWMAV.In addition,these work provide a feasible solution method and the design parameter selection basis for future au-tonomous flight attitude control mechanism and the solution of the dynamic problem involved in wingbeat dynamics and wing passive pitch motion of bio-insect FWMAV.