1 / 57

By: John den Engelse Date: 19 – 6 - 2013

Master Thesis at SKF: Lateral force estimation acting at a vehicle wheel using a hub bearing unit equipped with strain gauges and Eddy-current sensors. By: John den Engelse Date: 19 – 6 - 2013. Presentation overview. Introduction Research goals Strain gauge measurements

makaio
Télécharger la présentation

By: John den Engelse Date: 19 – 6 - 2013

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. Master Thesis at SKF:Lateral force estimation acting at a vehicle wheel using a hub bearing unit equipped with strain gauges and Eddy-current sensors By: John den Engelse Date: 19 – 6 - 2013

  2. Presentation overview • Introduction • Research goals • Strain gauge measurements • Eddy-current sensor measurements • Field- / validation measurements • BETSY calibration method • Conclusions

  3. 1 Introduction

  4. Introduction: LoadSensingBearing (LSB) • Whywould we like to measureforces? • Monitoring the mechanicalloads of a bearing. • Control the activesafetysystems in vehicleslike the ABS • (longitudinalforce) and ESC (lateralforce). • Measure the verticalload in, forinstance, trucks. Introduction – Research goals – Strain gauge measurements – Eddy-current sensors measurements – Field- / validation measurements - …

  5. Introduction: LoadSensingBearing (LSB) • How?  A loadsensinghubbearing unit instrumentedwith: • 6 straingauges: deformation of the bearingouter ring. • 2 Eddy-current sensors: tiltingmovement of the ABS-ring. Introduction – Research goals – Strain gauge measurements – Eddy-current sensors measurements – Field- / validation measurements - …

  6. 2 Research goals

  7. Research goals • Lateralforceestimation, acting at a vehiclewheel, using • straingauges and Eddy-current sensors. • Calibration of the loadsensingbearingusing the • Bearing Test System (BETSY) Introduction – Research goals – Strain gauge measurements – Eddy-current sensors measurements – Field- / validation measurements - …

  8. 3 Straingaugemeasurements

  9. Straingaugemeasurements • The straingaugesmeasure the deformation of the bearingouter ring at sixplacesalong the circumference. • The deformation provides informationabout the loadsactingon the bearing. Introduction – Research goals – Strain gauge measurements – Eddy-current sensors measurements – Field- / validation measurements - …

  10. Straingaugemeasurements • Sowhat happens? Introduction – Research goals – Strain gauge measurements – Eddy-current sensors measurements – Field- / validation measurements - …

  11. Warning The following slide features a mathematical trick performed by a professional and under the supervision of a professional. Accordingly, the TU Delft and the students must insist that no one attempt to recreate of re-enact any trick or activity performed on this slide.

  12. Straingaugemeasurements: MLRA • Multivariate Linear Regression Analysis (MLRA): The output is assumed to be a linear combination of the input and higher order terms of the input. • For one single dimension: • For multi input multi output Introduction – Research goals – Strain gauge measurements – Eddy-current sensors measurements – Field- / validation measurements - …

  13. Straingaugemeasurements: MLRA • Absolute valueproblem • Difference in sensitivityforFy < 0 N and Fy > 0 N • Difference in response for 0 Hz < f < 1 Hz and 1 Hz < f < 10 Hz Introduction – Research goals – Strain gauge measurements – Eddy-current sensors measurements – Field- / validation measurements - …

  14. Straingaugemeasurements: Fyestimationblock diagram Introduction – Research goals – Strain gauge measurements – Eddy-current sensors measurements – Field- / validation measurements - …

  15. 4 Eddy-current sensor measurements

  16. Eddy-current sensor measurement • Why (inductive) Eddy-current sensor measurements? • The straingauges are subject to the absolute valueproblem. • Strainmeasurements are subject to low frequent thermalinfluences. Introduction – Research goals –Strain gauge measurements – Eddy-current sensors measurements – Field- / validation measurements - …

  17. Eddy-current sensor measurement • ABS-ring integrated in the seal of the bearing. 48 holes and • 48 spokes. • The tiltingmovement of the ABS-ringgivesanestimate of the • lateralforceFyactingon the bearing. Introduction – Research goals –Strain gauge measurements – Eddy-current sensors measurements – Field- / validation measurements - …

  18. Eddy-current sensor measurement • TwoEddy-current sensors are mountedinto the knuckle. Introduction – Research goals –Strain gauge measurements – Eddy-current sensors measurements – Field- / validation measurements - …

  19. Eddy-current sensor measurement: Signal • The change in the lowervalues provides the information • aboutFy Introduction – Research goals –Strain gauge measurements – Eddy-current sensors measurements – Field- / validation measurements - …

  20. Eddy-currentmeasurement: Low valuealgorithm • Algorithm to retrieve these lowervalues. • Basedsignalderivative • Maximum change per time sample ∆ymax • Aninitialcondition y0 (the equilibriumvalue) • The wheel speed Discontinious output Continuous output Introduction – Research goals –Strain gauge measurements – Eddy-current sensors measurements – Field- / validation measurements - …

  21. 5 Field measurements

  22. Field measurements • The LSB equipment has been built in a BMW E60 and tests • have been performed at the test track at SKF …– Eddy-current sensors measurements – Field- / validation measurements– BETSY calibrationmethod - Conclusions

  23. Field measurements • Movie: Circle run at 30 km/h …– Eddy-current sensors measurements – Field- / validation measurements– BETSY calibrationmethod - Conclusions

  24. Field measurements • A Kistler VELOS force measuring wheel is used as reference …– Eddy-current sensors measurements – Field- / validation measurements– BETSY calibrationmethod - Conclusions

  25. Field measurements: Tilt vsFy • Eddy-current sensor measurement. • Data is approximatedby a 2nd and a 6th order polynomial: • Accuracyvsextrapolationcharacteristics N N …– Eddy-current sensors measurements – Field- / validation measurements– BETSY calibrationmethod - Conclusions

  26. Field measurements • Strainmeasurement …– Eddy-current sensors measurements – Field- / validation measurements– BETSY calibrationmethod - Conclusions

  27. Field measurements : Fyestimation • Twoforceestimationalgorithms. Both foranin-situcalibration • and a BETSY calibration. • Using 4 MLRA on the straingauges and use the Eddy-current sensors for the determination of the direction. • Usingboth the Eddy-current sensors and the straingaugesfor theforceestimation. …– Eddy-current sensors measurements – Field- / validation measurements– BETSY calibrationmethod - Conclusions

  28. Field measurements : Algorithm 1 • Using 4 MLRA on the straingauges and use the Eddy-current • sensors for the determination of the direction. …– Eddy-current sensors measurements – Field- / validation measurements– BETSY calibrationmethod - Conclusions

  29. Field measurements: Algorithm 2 • Usingboth the Eddy-current sensors and the straingauges • for the forceestimation …– Eddy-current sensors measurements – Field- / validation measurements– BETSY calibrationmethod - Conclusions

  30. Field measurements : Fyestimation, result • Estimatedforcevs time forbothalgorithms. …– Eddy-current sensors measurements – Field- / validation measurements– BETSY calibrationmethod - Conclusions

  31. Field measurements : Fyestimation, result • Estimatedforcevsmeasuredforceforbothalgorithms. …– Eddy-current sensors measurements – Field- / validation measurements– BETSY calibrationmethod - Conclusions

  32. Field measurements : Fyestimation, result • Estimationerrors In-situcalibration …– Eddy-current sensors measurements – Field- / validation measurements– BETSY calibrationmethod - Conclusions

  33. 6 BETSY calibration

  34. Straingaugemeasurements: BETSY • What is BETSY and why do we want to useit? • The Bearing Test System is a 5 Degree of Freedom (DoF) • system, where forces and moments are applied in 5 DoF • by hydraulic actuators. …– Eddy-current sensors measurements – Field- / validation measurements – BETSY calibrationmethod- Conclusions

  35. BETSY calibration: strain εBETSY = c3 ∙ Fy + c4 εvehicle = c1 ∙ Fy + c2

  36. BETSY calibration: Eddy-current sensors Good! 

  37. Field measurements : Fyestimation, result • EstimatedFyvs time forbothalgorithms …– Eddy-current sensors measurements – Field- / validation measurements – BETSY calibrationmethod- Conclusions

  38. Field measurements : Fyestimation, result • EstimatedFyvsmeasuredFyforbothalgorithms. …– Eddy-current sensors measurements – Field- / validation measurements – BETSY calibrationmethod- Conclusions

  39. Field measurements : Fyestimation, result • Estimationerrorsusing a BETSY calibration • So we canuse BETSY forcalibration? …– Eddy-current sensors measurements – Field- / validation measurements – BETSY calibrationmethod- Conclusions

  40. Reproducibility: strain • Reproducibility is necessaryforcalibration of a whole • productionline of LSB Not good!  …– Eddy-current sensors measurements – Field- / validation measurements – BETSY calibrationmethod- Conclusions

  41. Reproducibility: Eddy-current sensors • Reproducibility is necessaryforcalibration of a whole • productionline of LSB 2011 2012 Good!  …– Eddy-current sensors measurements – Field- / validation measurements – BETSY calibrationmethod- Conclusions

  42. 7 Conclusions

  43. Conclusions: lateralforceestimation • In the semi-staticfrequency range the straingauges as well as the • Eddy-current sensors canbeusedforforceestimationwitherrors • rangingfrom 15 % - 20 %. • In the dynamicfrequency range the lateralforce is notcorrelatedwith • the strain and ABS-ringdeflection. • Regarding the Eddy-current sensors BETSY canbeusedforcalibration. • Regarding the straingauges sensors BETSY cannotbeusedfor • calibration. …– Eddy-current sensors measurements – Field- / validation measurements – BETSY calibrationmethod - Conclusions

  44. Questions? Thankyouforyourattention !

  45. Backupslides

  46. Introduction: LoadSensingBearing • Whatforces act on a vehicle? • 3 forces: • Fx = longitudinalforce • Fy = lateralforce • Fz = verticalforce • 3 moments: • Mx = moment around the x-axis • My = moment around the y-axis • Mz = moment around the z-axis

  47. Straingaugemeasurements: Appliedloads • Cycle consisting of 24 load steps. • Load steps with 10 seconds of duration. • Between each load step a 10 seconds interval of running without load is inserted. • Combinations of static and dynamicforces are applied.

  48. Straingaugemeasurements: Signalconditioningprocess • Filtering • Static offset and drift • Inverted signal strain gauge 3 • No-load intervals • Scaling to physical dimensions

  49. BETSY calibration • Field • BETSY • BETSY and field • Some differences are present • How can we compensate for • those differences. …– Eddy-current sensors measurements – Field- / validation measurements – BETSY calibrationmethod- Conclusions

  50. BETSY calibration Bydescribingbothsides of the V-shapeby a 1st order polynomialtwocoefficients, Ca and Cb, canbederivedforbothpositive and negativeFy to transform te one to the other. (So 4 coefficients in total). Εleft,BETSY = c1,left ∙ Fy,left + c2,left εright,BETSY = c1,right ∙ Fy,right + c2,right BETSY Εleft,field = c3,left ∙ Fy,left + c4,left Field εright,Field = c3,right ∙ Fy,right + c4,right

More Related