An Evaluation Method of Wind Tunnel Test Balance Based on Approximate Entropy of Acceleration Signal

Abstract

A wind tunnel test balance assessment method based on acceleration signal approximate entropies mainly includes the steps that a model three-dimensional acceleration sensor, a framework three-dimensional acceleration sensor and a balance three-dimensional acceleration sensor are installed on the inner wall of the top end of an aircraft model, a framework model and a balance respectively; Fourier transformation is carried out on acceleration signals measured out by the three acceleration sensors in different directions, then a frequency spectrum signal is obtained, approximate entropy characteristic values of six frequency bands within 0-300 Hz are calculated out, the difference value between the approximate entropy characteristic values of the acceleration signals in the same direction of the model and the framework is calculated out, and the difference value between the approximate entropy characteristic values of the acceleration signals in the same direction of the model and the balance is calculated out; when the two difference values between the approximate entropy characteristic values in the different directions are within the specialized range, an assessment result determines that test data of the balance are credible, and when the two difference values are not within the specialized range, the assessment result determines that the test data of the balance are not credible. Consequently, model mechanical data measured out through the balance are accurate and reliable in a wind tunnel test, and more accurate and reliable test data are provided for aerospace aircrafts.

Description

technical field [0001] The invention relates to a method for calibrating and evaluating a wind tunnel test balance of an aerospace vehicle, in particular to a method for evaluating a wind tunnel test balance based on the approximate entropy of an acceleration signal. Background technique [0002] During the development of aerospace vehicles, in order to understand the performance of the aircraft and reduce the risk and cost of aircraft development, wind tunnel model tests are usually carried out. It is the most basic experimental item in wind tunnel test to measure the aerodynamic force and moment of the aircraft test model under various test conditions. The test principle is to fix a model support at the bottom of the wind tunnel, the upper end of the model support penetrates into the test model and is threaded with the fixed end of the balance, and the measuring end of the balance is threaded with the model frame in the test model; the model frame The test model is connec...

AI Technical Summary

Problems solved by technology

This calibration method has a long cycle and many steps, and can only calibrate the static characteristics of the balance, and cannot evaluate the dynamic characteristics of the balance under actual working conditions, which leads to the accuracy of the mechanical data of the wind tunnel test under the actual working conditions and the Reliability is difficult to determine, it cannot accurately and reliably evaluate the performance of aerospace vehicles, and cannot provide accurate and reliable test data for aerospace vehicles

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