1 / 26

Development of a multi-hole probe for UAV measurements

Development of a multi-hole probe for UAV measurements. Árpád Varga , PhD student Márton Balczó , research assistant. 5-hole probes. Why a 5-hole probe? 3D time resolved velocity vector measurement in a 40 -deg cone low-cost, robust. a : pitch b : yaw. pressure coefficients.

tokala
Download Presentation

Development of a multi-hole probe for UAV measurements

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Development of a multi-hole probe for UAV measurements Árpád Varga, PhD student Márton Balczó, research assistant

  2. 5-hole probes • Why a 5-hole probe? • 3D time resolved velocity vector measurement in a 40-deg cone • low-cost, robust a: pitch b: yaw

  3. pressure coefficients angle coefficients • q: dynamic pressure dyn. pressure correction coeff. • ∆p: corrected average pressure from the 4 side holes: to static pressure port

  4. During measurement: • measure pressures, • determine normalized coefficients, • calculate q, a, b using polinomial surfaces Principle - directional calibration • During calibration: • set velocity and flow angles • measure pressures • determine normalized coefficients • fit polinomialsurfaces toq, a, b.

  5. Rapid prototyping Manufacturing - spatial resolution • Traditional • soldering of copper tubes OD= 4mm, ID 0.5mm, L = 130mm • current method with 50mm resolution too rough

  6. Sensors, digital communication • Sensortechnics HCLA miniature temperature compensated, amplified sensors • communication during lab testing: 400 kHz I2C bus using a NI 8452I2C-USB interface: 0.4 ms readout time for 6 sensors: approx 800 Hz sampling rate

  7. Wind tunnel used for calibration • Blower type open test section wind tunnel • 350 mm cross section, 0,8%-os turbulence-intensity, max 24 m/s

  8. Directional calibration

  9. How to adjust calibration rig’s axis to the wind direction • adjust  angle in small steps • rotate probe around axis 0- 180 deg at each  angle • pressure coefficient change to be minimized

  10. Directional calibration • Control measurements in 600 random points: • angular error < 0.4° • q error < 2.5 Pa

  11. Dynamic calibration Ref. sensor: piezoresistive microphone up to 10kHz • Do frequency scan 1-500 Hz • Determine amplitude ratio and phase shift

  12. Reconstruction of the signal in time domain 45Hz sine 180Hz sine

  13. Signal reconstruction – noise measurement FFT Signal Standard deviation [Pa] Max. deviation [Pa] reference 0.2 1.2 measured 0.3 1.9 reconstructed 1.2 6.0

  14. Conclusions • 5HP probe developed and calibrated • low cost, digital sensors • zero alignment during calibration should be taken care of • temporal resolution is subject of damping from the tubing, with optimization and recompensation, up to 250 Hz can be achieved.

  15. Thank you for your attention!

More Related