Research On Suspended Measurement Of Pneumatic Six-dimensional Force

With the rapid development of aerospace and national defense research,greater demands were being placed on the quality of aerodynamic data in aircraft design and research,which requires more accurate measurement of aerodynamic six-dimensional force of aircraft model in wind tunnel test.Aiming at the problems of support interference and vibration in the wind tunnel test of a long and narrow aircraft model,a new type of aerodynamic six-dimensional force measurement device based on combined support is developed.The purpose of this study is to reduce the support interference and restrain the model vibration in wind tunnel experiments,so as to ensure the reliability and accuracy of the six-dimensional force measurement data.Firstly,aiming at the problems existing in the traditional wind tunnel test,a new type of aircraft model support method and a measurement principle of six-dimensional force of the model based on combined support are proposed.Based on the combined support method,the static analysis of the model is carried out,and the numerical relationship between the sensor output and the six-dimensional force acting on the aircraft model is established.According to the research content and requirements of this subject,the key technical problems and difficulties needed to be solved are put forward,which provides a theoretical basis for the development of model pneumatic six-dimensional force measurement device..Secondly,in order to ensure the accurate measurement of the force on the model,a high-performance force sensor is developed.Based on piezoelectric mechanism and piezoelectric effect of quartz crystal,piezoelectric coefficient matrix is deduced.Based on piezoelectric coefficient matrix and actual measurement requirements,combined with the requirements of the use,installation and maintenance of sensors in support measurement schemes,piezoelectric unidirectional force sensor for measuring tension line and piezoelectric three-way pressure sensor for measuring the force exerted on tail struts are developed.The piezoelectric sensor has the advantages of high linearity,small repeatability error and small inter-directional interference.It has high measurement accuracy and meets the requirements of test measurement.It provides a high-precision force sensor for the measurement of six-dimensional force on the following aircraft model and ensures the measurement accuracy.Then,based on the principle of aerodynamic six-dimensional force measurement of aircraft model,a model support measuring device with variable parameters is designed,which can accurately measure the aerodynamic six-dimensional force of aircraft model under different support states.The three-dimensional modeling and static analysis of the device are carried out by Pro/E and ANSYS Workbench,and the correctness and reliability of the design scheme are verified.In addition,according to the structure and measurement range of the support measuring device,the weighted force source is selected as the force loading device,and a calibration device for six-dimensional force loading is designed,and the six-dimensional force calibration loading model of the device is established.Finally,according to the measurement principle and the six-dimensional force solving equation,the main parameters affecting the solution of the equation are mainly studied and the secondary parameters are neglected to obtain the simplified equation.According to this equation,the suitable range of stretching angle is deduced.Aiming at measuring deviation angle of tension line and installing deviation angle of triaxial force sensor,the sensitivity of solving equation to these two kinds of errors is studied,and the error range of the two kinds of errors is demanded to ensure the accuracy of solving equation and to provide reference for the selection of subsequent experimental parameters.