To solve the discreteness problem of maximum overload measurements in high speed airdrop tests, wavelet entropy is used to compare and analyze the test data and simulation data. Results show that the large attitude difference of the dummy directly causes the poor repeatability of test measurements, while the attitude uncertainty of the dummy from the start of the airdrop to the parachute straightening moment is the main source of the problem. The wavelet entropy obtained from the experimental data and simulation results is consistent with the physical nature of the airdrop system, exhibiting the same variation trend as that of the airdrop speed and the airdrop system mass. Therefore, it is unreasonable to consider only the measurement value of the maximum overload and ignore the system uncertainty in the experimental study of the life-saving parachute open load. Hence, it is suggested to control the dummy posture before straightening of the parachute.
LIU Danyang
,
KE Peng
,
YANG Chunxin
,
MA Kunchang
,
QI Xiaoling
. Maximum opening overload uncertainty of high speed airdrop of life-saving parachutes based on wavelet entropy[J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2020
, 41(8)
: 123627
-123627
.
DOI: 10.7527/S1000-6893.2020.23627
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