Laboratory Test of Vibration of Micro/Nano Satellite for Environment Test Standardization

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1 Laboratory Test of Vibration of Micro/Nano Satellite for Test Standardization Amgalanbat Batsuren, Toru Hatamura, Hirokazi Masui, Mengu Cho Interaction Kyushu Institute of Technology 5 th Nano Satellite Symposium, November 20 23, , Tokyo, Tk Japan

2 Background Micro/Nano satellite: Low cost and fast delivery using COTS. Existing testing standard not suitable for micro/nano satellites. The unit QT(Qualification Test) for large/medium satellite require too many margins. Needs to Define an adequate level of the unit test level. KIT initiated NETS (Nano Satellite Test Standardization) project in Proposing affordable and reliable tests to the space community. Various environment tests according to NETS projects. Basic research QT level vibration test. The 5th Nano Satellite Symposium, November 20 23, 2013, Tokyo, Japan 2

3 Unit QT level strategy Existing QT too much margins QT guarantee guaranteedesign for space Products no test history Unit QT level in this standard give minimum assurance Buyers get minimum assurance Customer may test again to their specification The 5th Nano Satellite Symposium, November 20 23, 2013, Tokyo, Japan 3

4 Approach Statistics of experimental data Hz : Statistics of various satellites Hz : Vibration test measure at various internal points Amplification factor of base vibrations Identify the minimum amplification factor Propose Unit QT level by multiplying PSD by AF. The 5th Nano Satellite Symposium, November 20 23, 2013, Tokyo, Japan 4

5 Experimental System The 5th Nano Satellite Symposium, November 20 23, 2013, Tokyo, Japan 5

Base acceleration: Adopted from SMC S 016 (US Standard) Peak kpsd levels l and resonant frequencies were identified.

6 Outline of vibration test Test article: Dummy satellite (the Hodoyoshi 3 satellite AT test data was used for update dummy satellite test results) Size: 50cm x 50cm x 50cm Weight: 50kg class Vibration: Random vibration. Base acceleration: Adopted from SMC S 016 (US Standard) Peak kpsd levels l and resonant frequencies were identified. d To compute Normal tolerance limit, followed the Dynamic Criteria, NASA HDBK The 5th Nano Satellite Symposium, November 20 23, 2013, Tokyo, Japan 6

7 Test article RF transmitter PCU(Power Control Unit) OBC(On board computer) Battery Dummy satellite Size: 50cm x 50cm x 50cm DM (Dummy masses) with heater inside Structure flight quality Hodoyoshi 3 satellite vibration test data are also used for update. The 5th Nano Satellite Symposium, November 20 23, 2013, Tokyo, Japan 7

8 Test article Four quarter tatami viewed from the top Seen as the popular layout of tatamis yo jou han 4.5 tatami room tatami.com/archives/491 The 5th Nano Satellite Symposium, November 20 23, 2013, Tokyo, Japan 8

9 Test procedure Satellite fixed to vibration machine Accelerometers attached Random vibration tests Testing Peak PSD and resonant frequency Finding vibration modes Statistical methods to find Unit itqt levell Raw Data Analysis Final Statistical Analysis The 5th Nano Satellite Symposium, November 20 23, 2013, Tokyo, Japan 9

10 Random vibration spectrum profile Power Spectral Density (PSD) plot: Mean square acceleration per unit bandwidth Random vibration excites all the frequencies in a defined spectrum at any given time. 1 For the experiment: 0.1 Adopted from SMC S 016 (US Standard) PSD, G^2/ /Hz Control1 Control2 Upper limit Low limit The 5th Nano Satellite Symposium, November 20 23, 2013, Tokyo, Japan Frequency, Hz 10

Satellite Symposium, November 20 23, 2013,

:Measured PSD value PSD b : Base level If

11 +Z Amplification Factor(AF) +X +Y Acc. 1(z) Acc. 3(z) Acc. : Accelerometers Acc. 2(z) Acc. 4(z) Acc.5,6 6for horizontal vibration The 5th Nano Satellite Symposium, November 20 23, 2013, Tokyo, Japan AF : Amplification factor PSD m :Measured PSD value PSD b : Base level If AF=1, no amplification If AF>1, vibration amplified If AF<1, attenuated vibration i 11

12 Test results and data analysis The 5th Nano Satellite Symposium, November 20 23, 2013, Tokyo, Japan 12

13 Test result: PSD waveform PSD, G^2 2/Hz DM1 PCU Battery Measured at 18points Position: +x internal panel Base level: 9Grms Vibration : Vertical Accelerometer: z axis Frequency, Hz The 5th Nano Satellite Symposium, November 20 23, 2013, Tokyo, Japan 13

14 Example of Test results: Amplification Factor Sensor position: DM1, vertical 10 DM1 Amp plification Factor 1 Peak, AF= Frequency [Hz]

15 Test data statistics of dummy satellite( hz) The peak amplification factors and resonant frequencies were dd deduced d within three frequency ranges. Approximated these data by lognormal distribution. Resonant frequency[hz] Horizontal1 Horizontal 2 Axial direction DM PCU BATTERY DM OBC RF DM DM DM DM DM DM DM DM The 5th Nano Satellite Symposium, November 20 23, 2013, Tokyo, Japan Amplification factor Horizontal1 Horizontal 2 Axial direction DM PCU BATTERY DM OBC RF DM DM DM DM DM DM DM DM

Vibration response modes Local vibration mode 300 2000Hz

Wholesatellite mode 20 300Hz Entire satellite structure

16 Vibration response modes Local vibration mode Hz Internal panel structure Hz Hz Wholesatellite mode Hz Entire satellite structure The 5th Nano Satellite Symposium, November 20 23, 2013, Tokyo, Japan 16

17 Example of Vibration modes of micro/nano satellite Noticed two vibration modes: Whole satellite mode and Local vibration mode. The measurement data were divided into three frequency range: Hz: Whole satellite mode Hz: Local vibration mode Hz: Localvibration mode Horizontal Vibration response at internal panel The 5th Nano Satellite Symposium, November 20 23, 2013, Tokyo, Japan 17

18 Vibration modes of micro/nano satellite Local vibration mode due to mostly internal panels arrangement Vertical Vibration response at internal panel The 5th Nano Satellite Symposium, November 20 23, 2013, Tokyo, Japan 18

19 Statistical method to deduce Normal tolerance limit The 5th Nano Satellite Symposium, November 20 23, 2013, Tokyo, Japan 19

20 Example of Goodness Of Fit normality distribution_ hz_lognormal Perpendicular to the axial(x) r to the ax ial(x) Per rpendicula Percent f l l h l l After evaluating normality, we decided to choose lognormal as the distribution of Amplification factor. 20

21 Normal Tolerance Limit(NTL) calculation The 5th Nano Satellite Symposium, November 20 23, 2013, Tokyo, Japan 21

22 Normal tolerance limit of amplification factor in logarithm of the dummy satellite in the range: Hz Resonant frequency[hz] Horizontal Horizontal Vertical (x) (y) (z) Average Standard deviation Lower value Upper value Horizontal (x) Amplification factor Horizontal (y) Vertical (z) Average 0.39(2.4) 0.49(3.1) 0.14(1.4) Standard deviation 0.20(1.6) 0.28(3.1) 0.11(1.3) NTL (Min) 0.06(1.15) 0.02 (1.05) 0.04(1.1) NTL (Max) 0.72(5.25) 0.96 (9.12) 0.32(2.09) 1.15 : maximum value of minimum Normal tolerance limit among all direction. 115was 1.15 chosen as the unit QT level in the range: 300Hz and 1000Hz. 22

23 Amplification factor, Hz normal Satellite Horizontal x Horizontal y Axial direction Satellite A Satellite B Satellite C Satellite D Satellite E Satellite F

24 Normal tolerance limit of amplification factor in logarithm in the range: Hz (real values areshown in bracket). Resonant frequency [Hz] Horizontal 1 Horizontal 2 Vertical Average Standard deviation Lower value Upper value Amplification factor Horizontal1 Horizontal2 Vertical 0.80 (6.3) 0.82(6.6) 0.72(5.2) Standard d deviation 010( (1.2) 0.12(1.3) 0.17(1.5) NTL (Min) 0.62 (4.2) 0.61 (4.1) 0.42 (2.6) NTL (Max) 097( (9.3) 103( (10.7) 10(10) : maximum value ofminimum Normaltolerance limit amongallall direction. 4.2 was chosen as the unit QT level between 20Hz and 101Hz. 24

25 The amplification factor and resonance frequency range for unit QT test level ( Hz) 2000Hz) Results of three frequency ranges merged. Amplification factor of unit QT level between 20Hz and 2000Hz. The 5th Nano Satellite Symposium, November 20 23, 2013, Tokyo, Japan 25

26 Unit QT level ( Hz) Unit QT level= PSD(AT level) x Amplification factor 2 RMS SMC : 12.9Grms Rocket B : 11.8Grms Rocket C : 8.4Grms Propose Rocket B as Unit QT level. Frequency, Hz 26

27 Conclusion Basic research has been carried out to find Unit QT level. Amplificationfactor factor and range of resonant frequencies were considered. Unit QT test level has been proposed. p Future work: Finite Element Analysis (FEA) of small satellites structures will be carried out to update experimental results. The 5th Nano Satellite Symposium, November 20 23, 2013, Tokyo, Japan 27

28 Appendix The 5th Nano Satellite Symposium, November 20 23, 2013, Tokyo, Japan 28

29 Mounting of the Accelerometers +Z +X +Y Acc.1 Acc.2 Acc.3 Acc.4 Accelerometers attached at positions of internal and external panels. 29

30 Accelerometer data Charge amplifier (output 10V +10V) Flowchart of Data analyzing Time domain A/D conversion 5000 sample/sec FFT PSD Frequency domain Amplification Factor RMS Resonant frequency 30

31 Peak amplification factor, Hz position normal lognormal (X) (Y) Axial (Z) Log(x) Log(y) Log(z) DM PCU BATTERY DM OBC RF DM DM DM DM DM DM DM DM

32 Normal tolerance limit of amplification factor in logarithm of the dummysatellite inthe range: Hz Resonant frequency[hz] Amplification factor Horizontal (x) Horizontal (y) Vertical (z) Horizontal (x) Horizontal (y) Vertical (z) Average Standard deviation Lower value Upper value Average 0.33(2.1) 0.32(2.1) 0.29(1.9) Standard deviation 0.68(4.8) 0.70(5.0) 0.47(2.9) NTL (Min) 0.81 (0.15) 0.85 (0.14) 0.49 (0.32) NTL (Max) 1.47(29.5) 149( (30.9) 107( (11.75) No amplification in Hz range. No amplification in Hz range. We simply take the amplification is uniform at unity between 1000Hz and 2000Hz 32

33 Calculation of vibration transmittance apartfrom resonant frequency range τ: Transmittance, ζ: damping rate, κ: frequency rate, f and f 0 : base and resonant frequency. Inourcase case, transmittance is equalto the amplification factor. For calculating l the gradient value from 270Hz to higher, amplification factor and frequency were extrapolated until the amplification factor became The amplification became 1.15 at 390Hz. Assumed ζ=

Response spectrum Time history Power Spectral Density, PSD

Response spectrum Time history Power Spectral Density, PSD A description is given of one way to implement an earthquake test where the test severities are specified by time histories. The test is done by using a biaxial computer aided servohydraulic test rig.