Active Suspension System

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Active Suspension System

  1. 1. Jan 2004 Mechanical and Industrial Engineering Active Suspension System
  2. 2. Jan 2004 Behzad Samadi Vehicle Dynamics Lateral dynamics Handling: transient and steady state cornering Stability: rollover and yaw
  3. 3. Jan 2004 Behzad Samadi Vehicle Dynamics Longitudinal dynamics Acceleration Braking
  4. 4. Jan 2004 Behzad Samadi Vehicle Dynamics Vertical dynamics Ride comfort: Noise, vibration and harshness (NVH)
  5. 5. Jan 2004 Behzad Samadi Vehicle Dynamics Suspension design Ride comfort Road holding Handling
  6. 6. Jan 2004 Behzad Samadi Active Suspension Active suspension systems move each wheel up and down to control body motion in response to road abnormalities. With an active suspension, a vehicle can simultaneously provide the smooth ride of a soft suspension along with superior handling associated with a firm suspension.
  7. 7. Jan 2004 Behzad Samadi Car manufacturers GM Ford Daimler Chrysler VW Toyota …
  8. 8. Jan 2004 Behzad Samadi Cadillac SRX Magnetic Ride Control
  9. 9. Jan 2004 Behzad Samadi Range Rover Electronic Air Suspension (EAS)
  10. 10. Jan 2004 Behzad Samadi Mercedes Benz CL 55 AMG Active Body Control (ABC)
  11. 11. Jan 2004 Behzad Samadi Adaptable Variable Suspension AVS allows the driver to select from four suspension settings - comfort to sports firm – at the flick of a switch. Computerized sensors also monitor steering and wheel speed to eliminate dive, squat, lean and roll.
  12. 12. Jan 2004 Behzad Samadi Active Height Control Suspension Low makes it easier for passengers to enter and exit. High accommodates rough terrain. It takes 10-15 seconds to raise the vehicle and 3-8 seconds to lower it.
  13. 13. Jan 2004 Behzad Samadi Active Body Control Active Body Control is an active suspension and damping system which automatically adjusts the chassis settings to the driving situation. Body movements when moving off, cornering and braking are reduced as necessary and the optimum level of damping is provided. The ABC chassis system offers sports car style responsiveness without compromising comfort. This apparent conflict of interests is resolved through a combination of active control and passive damping. http://www.mercedes-benz.com
  14. 14. Jan 2004 Behzad Samadi Active Body Control
  15. 15. Jan 2004 Behzad Samadi Active Body Control - Benefits Reduced roll and pitch when braking and accelerating Less body roll when cornering Sporty driving dynamics and optimum comfort Greater directional stability in all situations Self-leveling suspension
  16. 16. Jan 2004 Behzad Samadi Active Body Control Sensors: Level Vertical acceleration Lateral acceleration Actuators: High pressure hydraulic
  17. 17. Jan 2004 Behzad Samadi
  18. 18. Jan 2004 Behzad Samadi Body Control Damping
  19. 19. Jan 2004 Behzad Samadi Active Roll Control TRW Automotive: http://www.trw.com
  20. 20. Jan 2004 Behzad Samadi Active Roll Control
  21. 21. Jan 2004 Behzad Samadi Dynamic Body Control
  22. 22. Jan 2004 Behzad Samadi Magne Ride Delphi Automotive: http://www.delphi.com
  23. 23. Jan 2004 Behzad Samadi Magne Ride – How it works Magneto-rheological (MR) fluid is a suspension of magnetically soft particles such as iron microspheres in synthetic hydrocarbon base fluid. There are two work states: Not magnetized state: The particles exhibit a random pattern. Magnetized state: The applied magnetic field aligns the metal particles into fibrous structures, changing the fluid rheology to a near plastic state. By controlling the current to an electromagnetic coil inside the piston of the damper, the MR fluid's shear strength is changed, varying the resistance to fluid flow. By fine tuning of the magnetic current, continuously variable real time damping is gained.
  24. 24. Jan 2004 Behzad Samadi Magne Ride - Features Simple monotube design with no electro-mechanical valves or small moving parts Improved performance and reliability over valve- based competitive systems Full software tunable damping characteristics provide excellent low frequency body control without excessive harshness at high velocities Excellent roll control during transient steering and evasive maneuvers Wide range of force control and high bandwidth for fast response Low power requirements (20 W per damper max)
  25. 25. Jan 2004 Behzad Samadi Magne Ride - Benefits Flatter ride -- by controlling vehicle body motions Greater sense of safety and security -- due to improved road-holding capabilities Enhanced handling -- by controlling the lateral and longitudinal load transfer characteristics of the suspension during transient movements Road isolation -- by reducing the transmission of high-frequency road disturbances through the dampers Greater vehicle dynamics control when combined with unified chassis control
  26. 26. Jan 2004 Behzad Samadi ROADMASTER http://www.activesuspension.com
  27. 27. Jan 2004 Behzad Samadi Suspension control strategies
  28. 28. Jan 2004 Behzad Samadi Active suspension
  29. 29. Jan 2004 Behzad Samadi Quarter Car Model
  30. 30. Jan 2004 Behzad Samadi Quarter Car Model Equations of motion:
  31. 31. Jan 2004 Behzad Samadi Quarter Car Model State equations:                       −+                 − + − − − = r a s us us us s s s s s s us us us uss us s us us x F m m c m z m c m c m k m c m cc m k m k z & & 0 1 1 00 10 0 1100 0100 `
  32. 32. Jan 2004 Behzad Samadi Optimal Control
  33. 33. Jan 2004 Behzad Samadi Optimal Control - LQR dtNuzRuuQzzJ TTT ∫ ∞ ++= 0 )2( T s s s s s s s s s s s s ss s s s s s ss s ss s ss s s m c r m c r m k rN m r R m c r m c r m ck r m c r m c r m ck r m ck r m ck r m k rr Q       −==                   −− − −+ = 2222222 2 2 2 2 222 2 2 2 222 2222 2 21 0, )()(0 )()(0 )(0 0001
  34. 34. Jan 2004 Behzad Samadi
  35. 35. Jan 2004 Behzad Samadi
  36. 36. Jan 2004 Behzad Samadi

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