Mechanism Design And Optimization Of Counterbeat Flapping Wing Multi-attitude Micro Aerial Vehicles

Flapping wing micro aerial vehicles(FWMAVs)have more advantages over fixedwing and rotary-wing aerial vehicles at small scales.At current,successful research on FWMAVs mainly focuse on the double-wing bird-like micro-flapping aircraft,while some related research have shown that quadruple-wing flapping wings can generate more and more stable lift.With less undulation fluctuations,and are more suitable for carrying vision sensors,image and video transmission equipment,etc.And has a larger flight load,better flight capability and more complex mission execution capability.In this paper,we develop a mechanism design and optimization of a multi-attitude micro air vehicle with counterbeat flapping wings based on the current research and inspired by the difficult multi-attitude flight maneuvers of flying creatures in nature,which mainly includes the following.Firstly,the flight parameters of the studied FWMAV are determined based on the bionic equation as the reference indexes for the design work.The multi-attitude flight control mechanism of the studied FWMAV are determined through analysis including pitch,yaw and roll.The dihedral angle control mechanism and tail control mechanism are designed.By analyzing the existing FWMAV driving mode,transmission mode and wing structure,flapping-wing mechanism’s type is determined.And mechanism rod length is calculated according to the given motion parameters and correlation formula.And motion simulation test of the mechanism is completed.Finally,the wing type and wing size of the FWMAV are determined based on the current research results and bionic reference indexes.Secondly,according to the preliminary determined counterbeat-flapping wing structure.The kinematic and dynamical model of the mechanism is established.The calculation method of the angle,angular velocity and angular acceleration of each lever of the flapping wing mechanism based on the crank angle is given.The relationship between the driving torque and the aerodynamic torque of the counter-flapping wing is established by the dynamical equation.Then,two kinds of flapping wing aerodynamic analysis methods are proposed,fluid simulation method and experimental method are used to optimize flapping wing mechanism and flapping wing ribs respectively.The specific methods and steps of simulation are given,the aerodynamic and energy consumption measurement platform is designed.Thirdly,the optimization of the counterbeat-flapping wing structure,including the rod length and motion parameters,is carried out with the objective of improving the average lift of the counterbeat-flapping wing vehicle during hovering.Based on the results,the relationship between the maximum Travel Velocity-Ratio Coefficient and the flapping angle amplitude is obtained for a given design parameter and the permissible transmission angle.Based on the numerical simulations,the length and motion parameters of the counter-flapping mechanism are obtained when the average lift is maximum.Compared with the original scheme,the lift of flapping wing motion is obviously improved,and the model of flapping wing mechanism is established.Finally,the optimization of the wing ribs and the prototype of the counterbeatflapping wing multi-attitude micro vehicle were carried out.With the materials of airfoil and wing ribs was determined,using the designed and manufactured aerodynamic test platform and energy consumption test method,under the premise that the airfoil shape and wing size have been determined,we analyzed and compared the lift,energy consumption and lift/energy consumption ratio curves of the counterbeat-flapping wing with different wing ribs layouts.To improve flapping-generate lift and reduce energy consumption,the wing ribs optimization work of the counterbeat-flapping wing was finished.Finally,based on the results of this paper,the prototype was developed and have done the test.The results indicate that the weight and size of the prototype meet the expected design requirements,FWMAV’s multi-attitude flight control mechanism are reasonable and feasible,the average lift experimental results are more consistent with the fluid simulation results,and the force perpendicular to the fuselage direction is effectively suppressed which will be beneficial to hovering flight.