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# Analysis of passive quarter model suspension system; enhanced adaptation to semi-active control.

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Analysis of passive quarter model suspension system

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### Analysis of passive quarter model suspension system; enhanced adaptation to semi-active control.

1. 1. Analysis of Passive Quarter Model Suspension System; enhanced adaptation to Semi-Active control By: Matthew Fenech Tutor: Ing.Claire Seguna
2. 2. Vehicle Suspensions Aims of a Suspension System •Vehicle Isolation from road disturbances •Link between the road and the vehicle •Supporting the vehicle’s static weight
3. 3. Types of Suspension Systems •Passive •Active •Semi-Active • EH • ER • MRF
4. 4. Scopes and Objectives ofWork • Research of passive & semi-active Suspension Systems • Mathematical modelling • Data acquisition (real) to be put in the model (20mph)(tyre) • Math models generation on SIMULINK® • Hardware Design Stages • Semi-Active Control Study • Semi-Active Model • Data analysis of both systems and the rig response
5. 5. Mathematical Modelling Sprung Mass Unsprung Mass Road
6. 6. Mathematical Modelling (Free body Diagram) 𝐹𝑠 = 𝑀 𝑦 (Upward Direction) y = 1 M1 [−ksy + ksx − csy + csx] Sprung Mass
7. 7. Mathematical Modelling (Free body Diagram) 𝐹𝑠 = 𝑀 𝑦 (Upward Direction) x = 1 M2 [k 𝑠 y − x + C 𝑠 y − x − k 𝑢𝑠 x − r − C 𝑢𝑠 𝑥 − r ] Unsprung Mass
8. 8. SIMULINK® Passive Model
9. 9. ParametricValues ModelValues M1 Sprung Mass 287kg M2 Unsprung Mass 35kg Ks Sprung Mass Stiffness 25500N/m Kus Tyre Stiffness 145000N/m Cs Sprung Damping 2500Ns/m Cus Tyre Damping 0 fn sprung Sprung Natural Frequency 1.5Hz fn unsprung Unsprung Natural Frequency 16Hz
10. 10. Semi-Active adaptation • Skyhook control • ON-OFF algorithm 1. Fa = cSad(y − x) 2. cSad = cmax, if ca > cmax ca, if cmin < ca < cmax cmin, if ca < cmin 3. ca = cskyy y−x , only valid when y y − x > 0 , otherwise ca=cmin
11. 11. Semi-Active damping control
12. 12. SIMULINK® Responses: Displacement, Step Passive 0.07115 m Semi-Active 0.05778 m
13. 13. SIMULINK® Responses: Displacement, Bump Passive 0.01727 m Semi-Active 0.01865 m
14. 14. SIMULINK® Responses: Acceleration, Step Passive 14.64 m/s2 Semi-Active 9.417 m/s2.
15. 15. SIMULINK® Responses: Acceleration, Bump Passive 13.13m/s2 Semi-Active 7.165m/s2
16. 16. SIMULINK® Responses:Wheel Deflection, Step Passive 0.006366m Semi-Active 0.018m
17. 17. SIMULINK® Responses:Wheel Deflection, Bump Passive 0.0495 m Semi-Active 0.02501 m
18. 18. Rig Design
19. 19. Passive SuspensionTest Rig
20. 20. Recommendations • Rig improvement • Cam Actuator, Motor Driven • LVDT • Acceleration Measurement • Structure Improvement • Further Frequency analysis
21. 21. Conclusion Step Input Displacement (m) Acceleration (𝐦/𝐬 𝟐 ) Wheel Deflection (m) Passive 0.07115 14.64 0.006366 Semi-Active 0.05778 9.417 0.018 % Improvement 18.79% 35.6% -64.3% Bump Input Displacement (m) Acceleration (𝐦/𝐬 𝟐 ) Wheel Deflection (m) Passive 0.01727 13.13 0.0495 Semi-Active 0.01865 7.165 0.02501 % Improvement -7.3% 45.4% 49.47%
22. 22. Thank you for your attention!
23. 23. Questions?
24. 24. Comfort Specs iso2631 Magnitude of OverallVibrationTotalValue Discomfort Response < 0.315ms−2 Not uncomfortable 0.315 ms−2 < 0.03 ms−2 Slightly uncomfortable 0.8 ms−2 < 1.6 ms−2 Fairly uncomfortable 0.5 ms−2< 1 ms−2 Uncomfortable 1.25 ms−2 < 2.5 ms−2 Very uncomfortable 2.0 ms−2 < Extremely uncomfortable
25. 25. Costs €118.51 €497.32 €59.46 €6.00 Costs Raw Material Components Literature Services
26. 26. Model Mass Acquisition Model & Specs WEIGHT Toyota Aygo, 1.0ltr, 5 Speed, 3 Door 1240kg Ford Fiesta, 4-Dr, sedan 1169kg Vw Polo 1030kg Bmw, 1-series, 116i 1350kg Citroen C2, 1.4i 956kg Average 1149kg
27. 27. Spring Selection (Sprung Mass) Spring-Sprung Mass (Kg) Natural Freq.=1.5Hz Stiffness (N/m) Stiffness (N/mm) Static Deflection (m) 1 9.425 88.83 0.09 0.1104 2 9.425 177.65 0.18 0.1104 3 9.425 266.48 0.27 0.1104 4 9.425 355.31 0.36 0.1104 5 9.425 444.13 0.44 0.1104
28. 28. Spring Selection (Unsprung Mass) Spring Unsprung Mass (Kg) Natural Freq.=16Hz K (N/m) K (N/mm) Static Deflection (m) Body mass 1.125 100.531 11369.78 11.37 0.0010 1 2.25 100.531 22739.57 22.74 0.0010 2 3.375 100.531 34109.35 34.11 0.0010 3 4.5 100.531 45479.14 45.48 0.0010 4 5.625 100.531 56848.92 56.85 0.0010 5
29. 29. Rig 5Kg response
30. 30. SIMULINK® Responses: RMS, Bump
31. 31. Rig 0.5 Kg Response
32. 32. Rig 0.5 Kg Response -20 -10 0 10 20 30 40 50 60 70 80 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 Displacement(m) Time (sec) Test 1 Test 2 Test 3
33. 33. SIMULINK® Responses: RMS, Step