1. 1 of 22 Measurement And Control Of Slip In a Continuously Variable Transmission B. Bonsen, T.W.G.L. Klaassen, K.G.O. van de Meerakker M. Steinbuch, P.A. Veenhuizen

2. 2 of 22 CVT Infinite number of ratios within a range Shifting while engaged Optimal use of IC engine

3. 3 of 22 CVT

4. 4 of 22 Slip Friction drive Slip between belt and pulley Wear Clamping force

5. 5 of 22 Efficiency Actuation losses Friction in Belt Bearing losses Lubrication

6. 6 of 22 Project goals Optimize CVT transmission efficiency by: –using alternative actuation system –lowering clamping force

7. 7 of 22 Lowering clamping force Advantage: –Less friction losses in the belt –Less actuation power –Less friction in the bearings –More torque on the wheels Disadvantage: –Increased risk of damage due to slip

8. 8 of 22 Measurement of slip Definition of slip Measurement of Calculation of

9. 9 of 22 Testrig

10. 10 of 22 Slip & Efficiency

11. 11 of 22 Slip & Friction

12. 12 of 22 Linearizing

13. 13 of 22 Variator model

14. 14 of 22 Nonlinear model

15. 15 of 22 Linearized model

16. 16 of 22 Eigenfrequencies

17. 17 of 22 Control Clamping force Ratio Speed

18. 18 of 22 Slip feedback F p s r g ref + - T d

19. 19 of 22 Clamping force Safety Actuation bandwidth Slip measurement

20. 20 of 22 Stability using slip feedback

21. 21 of 22 Experimental Results

22. 22 of 22 Conclusions Stable control of slip Robustness for torque peaks up to 30Nm Lower clamping force (-30%) Higher variator efficiency (+4%)