Development Of Strain Balance Suitable For Flapping Wing Micro Air Vehicle

Flapping wing micro air vehicle is a type of aircraft imitating insects and birds.It has many advantages such as high stability,good maneuverability,and small size,and has good application prospects.Aerodynamic performance is one of the important indicators for the design of flapping-wing miniature aircraft.Because the aerodynamic characteristics of flapping-wing micro-aircraft are completely different from ordinary aircraft,there is currently no perfect theory to analyze its aerodynamic characteristics.The aerodynamic characteristics can only be measured by wind tunnel experiments.The flapping-wing aircraft is light in weight,and the force of each component is small when flapping,which is not easy to measure.Therefore,this paper has developed a small-range six-component strain balance.The main research contents are as follows:In view of the characteristics of the force measuring balance required by the microaircraft,the form of the strain balance is selected,the characteristic classification and working principle of the strain balance are introduced,the appropriate strain gauge is selected,and the method of attaching the strain gauge is introduced.According to the requirements,the design form and component layout of the strain balance were selected,and the serial component layout was selected as the layout of the strain balance.And according to the actual situation,suitable materials are selected for the balance.According to the existing flapping-wing aircraft in the laboratory,the range of the three-component strain balance was first determined.The basic structure of the force measurement unit is designed,and its structure is theoretically calculated and simulated.The results show that the designed force measuring unit is only sensitive to the force of this component,and insensitive to the force or moment of the remaining components,and the coupling interference between dimensions is small.The overall structure of the three-component balance is designed with the basic structure of the force measuring unit.At the same time,the six-component strain balance is further developed based on the three-component strain balance.The torque measuring unit is designed,and the torque measuring unit is theoretically calculated and simulated.The designed torque measurement unit is only sensitive to the torque of this component.The overall structure of the six-component strain balance is designed and the static simulation,modal analysis and strength analysis of the two balances are carried out.It is found that the coupling error between the dimensions is small.The three-component and sixcomponent strain balances meet the required measurement requirements.Perform static calibration experiments on three-component and six-component strain balances.Firstly,the data acquisition system of the strain balance is determined,a suitable device is selected for collection,and the two balances are calibrated by the method of changing the attitude and the method of loading the weight on the pulley.The relationship between the output voltage of each component and the load is obtained,and the strain is analyzed.The linearity,sensitivity,return error,coupling error between dimensions,precision and accuracy of the balance and other indicators are obtained,and its calibration matrix and decoupling matrix are obtained.The results show that all the indicators of the three-component and six-component strain balances meet the requirements and can be used to measure the micro flapping-wing vehicle.