Piezoelectric multilayer triaxial accelerometer

Transcription

1 Piezoelectric multilayer triaxial accelerometer C. Mangeot 1, B. Andersen 1, and M. Havránek 2 1 Noliac Motion, 2 Noliac Systems Hejreskovvej 18, Kvistgaard, 3470, Denmark Version:

2 The accelerometer market Conventional systems Mostly piezoelectric Specific applications for piezoresistive Very mature market Families of sensors for each environment and performance range MEMS More recent developments Increasing number of applications

3 Conventional accelerometers Market dominated by shear mode sensors Mass Housing Piezoelectric element(s) (ring or plates) Acceleration direction

4 Conventional accelerometers A few bending type accelerometers Fulcrum Housing Acceleration direction Bending piezoelectric element(s) (ring or plates)

5 Conventional accelerometers + High performance (sensitivity, bandwidth, linearity) + Tolerant to environment + Large available range - Complex - Difficult to miniaturize, heavy - Costly

6 Conventional accelerometers Market status 1000 Endevco 35A Acceleration range (+/- G) Brüel Kjaer 4524 Kistler 8690C Mass (g)

7 MEMS accelerometers + Various principles + High volume, low cost + Light weight + Variable performance - Limited in terms of environment - Difficult to qualify for aerospace or military applications - Difficult to customize

8 Accelerometer development in the Noliac Group Cooperation within the group Noliac Motion (Denmark) Expertise in multilayer piezoelectric elements Noliac Ceramics (Czech Republic) Expertise in ceramic materials Noliac systems (Czech Republic) Expertise in piezo transducer development

9 Ceramic monolithic multilayer triaxial accelerometer () 6 regions electrically defined in the same piezoelectric body Patent pending Patent pending

10 Measurement principle X-Y axis Zones compressed by bending stresses Vibration direction Zones stretched by bending stresses Patent pending

11 Measurement principle X-Y axis: charge movements Patent pending

12 Measurement principle Z axis Vibration direction Stretched zone Compressed zone Patent pending

13 Measurement principle Z axis: charge movements Patent pending

14 Temperature compensation Temperature change: charge movements Patent pending

15 SWOT Expected advantages Low cost (simplicity) Compact, lightweight solution Temperature compensated High sensitivity Orthogonality of the axes Potential for high temperature application Potential disadvantages Heterogeneity X-Y vs. Z Low stiffness

16 Prototype design Dimensions Cross section 2 x 2 mm Free length 7 mm No seismic mass Symmetrical design Performance Calculated first resonance 15 khz Mass 0,68 grams

17 Prototype design Material Noliac Ceramics PCM53 Soft-doped PZT ceramic g 31 = -8, Vm/N T c = 350ºC Selected for its temperature stability Adaptable design High temperature versions possible High g versions possible

18 Prototype design Temperature stability 30% Impedance at serial resonance Relative impedance at serial resonance / 20ºC (%) 20% 10% 0% -10% -20% -30% -40% -50% Temperature (ºC) PIC255 PCM53 Pz27

19 Prototype design Temperature stability 4 Sensitivity at serial resonance Relative sensitivity at serial resonance / 20ºC (db) Temperature (ºC) PIC255 PCM53 Pz27

20 Prototypes Ceramic multilayer sensor

21 Prototypes Prototype on mount and demonstrator

22 Performance tests X axis 10 Sensitivity (pc/m.s-2) 1 0,75 0,72 0,76 0,69 0,62 0,62 0,63 0,65 0,65 0,66 0,69 0,71 1,00 0,63 0,86 0, Frequency (Hz)

23 Performance tests Y axis 10 0,66 0,68 0,66 0,70 0,76 0,75 0,74 0,70 4,20 4,06 Sensitivity (pc/m.s-2) 1 0,73 0,83 0,90 1,17 2,09 0, Frequency (Hz)

24 Performance tests Z axis 10 8,56 Sensitivity (pc/m.s-2) 1 0,87 0,78 0,87 0,81 0,85 0,89 0,87 0,82 0,88 1,09 1,31 2,35 0,95 0,28 0, Frequency (Hz)

25 Performance tests Homogeneity 10 Sensitivity (pc/m.s-2) 1 X-Axis Y-Axis Z-Axis 0, Frequency (Hz)

26 Performance Homogeneous results for all 3 axes Sensitivity 0,6-0,8 pc/m.s-2 for X-Y Sensitivity 0,8-1,0 pc/m.s-2 for Z Stable response over frequency range 10 Hz to 2 khz Low resonance (5 khz) due to the fixture

27 Summary + High sensitivity + Flat and homogeneous response + Light weight (0,68g ceramic) + Simple construction (low cost) - Bandwidth limited to 2 khz for this first prototype

28 Performance range Position on market 1000 Endevco 35A Acceleration range (+/- G) Brüel Kjaer 4524 Kistler 8690C Mass (g)

29 Conclusions Unique advantages Further development Packaging Integrated electronics Range adapted to each measurement Develop market potential High sensitivity, light weight, temperature stability, compatible with harsh environments Aerospace applications Instrumentation (f.ex. automotive)

30 Thank you for your attention NOLIAC A/S Charles Mangeot Version: