Aerodynamic derivative identification method and system based on wind tunnel free-flying test

Abstract

The invention, which relates to the field of aircraft model identification technology, discloses an aerodynamic derivative identification method and system based on a wind tunnel free-flying test so that the flying state of the aircraft can be simulated truly and thus an accurate aerodynamic derivative is obtained. A wind tunnel free-flying test system is arranged and is used for carrying out freedom releasing testing on an aircraft model to obtain testing data; the obtained testing data are analyzed to obtain attitude and angular velocity information of the aircraft; a corresponding dynamic model is established and unknown parameters of the model are determined; according to an output error method based on a maximum likelihood method, state quantity values being corresponding attitude angle and angular velocity values as well as attitude angle and angular velocity values obtained by testing are substituted into an objective function and a derivative, iterative calculation is carried out, the objective function is optimized continuously and thus the derivative reaches a minimum value, and the unknown parameter value is determined to be an identification result. The identification process is simple; the model precision is high; and the convenience of model parameter acquisition is improved.

Description

technical field [0001] The invention relates to aircraft model identification technology, in particular to an aerodynamic derivative identification method and system based on a wind tunnel free flight test. Background technique [0002] In the study of aircraft aerodynamic derivative identification, the commonly used test methods are the traditional forced oscillation test and flight test in the wind tunnel. [0003] The test conditions of the flight test are very dependent on the weather conditions. Due to the limitations of the weather conditions and a large number of disturbances in the atmosphere, the test conditions are difficult to control and it is difficult to make repeated tests, which affects the accuracy of the test data. Moreover, in the flight test, the identification actions made by the aircraft are relatively violent, which can easily lead to aircraft crashes and pose a risk of low safety. [0004] In order to avoid the above problems, the prior art uses a wi...

AI Technical Summary

Problems solved by technology

The high-frequency band will cause motion coupled with the structural mode, and the low-frequency band will cause some ups and downs and linear motions, resulting in impure test input and affecting the accuracy of test results

[0005] In summary, for the research on the identification of aerodynamic derivatives of aircraft, there is currently a lack of experimental devices and methods that can truly simulate the flight state of an aircraft and obtain accurate aerodynamic derivatives

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