Optimization Design And Verification Of RURS Flapping Wing Mechanism

Micro flapping wing aircraft(FMAV)can realize the whole movement through flapping wing mechanism.It has the advantages of light weight,small size,complex flight attitude,excellent concealment and flexibility,etc.At present,the typical flapping mechanism with single degree of freedom can only realize a single movement,while the multi-degree of freedom flapping mechanism has the problems of complex structure and too large mass.Therefore,the research group designed a kind of RURS flapping mechanism which can realize single drive input and multi-degree of freedom output.This paper starts from the existing RURS flapping wing mechanism,carries on the aerodynamics calculation to it,uses the simulation software to carry on the flapping wing characteristic parameter analysis and the bar characteristic analysis to the mechanism,thus carries on the further improvement and the strength check,lets the design of the RURS flapping wing mechanism to be able to better meet the lightweight and strength conditions.It provides a good idea and a useful supplement for the research of flapping wing aircraft.The main research results of this paper are as follows:Firstly,the RURS flapping mechanism is a kind of flapping mechanism which can realize single drive input and multi-degree of freedom output.Through the definition of the kinematic parameters of the flapping wing,the variation law of the three characteristic angles of the original mechanism,namely flapping Angle φ,torsion Angle α and deflection Angle θ,and the original motion trajectory are given.By referring to Willamette et al.’s flight model equation of hawk moth and combining with the motion of the mechanism of RURS,mathematical modeling of the mechanism was carried out,and reasonable aerodynamic force estimation was carried out.In addition,MATLAB was used to write programs to determine the lift and drag generated by wings of flapping wing aircraft at 15 Hz,20Hz and 30 Hz flapping frequency.With the increase of flapping frequency,the lift and drag generated by flapping wing also increase.The average lift force of flapping wing on one side in a cycle at 20 Hz is about 105 m N,which meets the lift requirement of the mechanism and provides a certain basis for future analysis and optimization.Combined with the aerodynamic calculation results,the influence of stress neograms,deformation neograms and motion trajectories of each component of the RURS flapping mechanism under three different flapping frequencies of 15 Hz,20Hz and 30 Hz was obtained by using ADAMS software simulation.With the increase of frequency,the stress concentration position of each bar has no obvious change,and the maximum stress value increases until it exceeds the allowable stress value of the material.The deformation position has no obvious change,but the deformation is also increasing.The motion track is also jitter continuously intensified,until the bar fracture.Finally,ANSYS/Workbench was used to optimize the mechanism topology.The modal analysis of the frame was carried out,and the optimization scheme was put forward and implemented according to the previous results.After optimization,ANSYS and ADAMS were used to analyze and compare the quality and stress concentration state of the mechanism before and after optimization.It was found that the performance of the link was improved under the condition of lightness,and the flapping wing characteristics of the mechanism itself were not significantly affected.It provides a reference for future prototype manufacture and further development.