Presentation on theme: "Passive, Semi-Active and Active Suspension System"— Presentation transcript:
1 Passive, Semi-Active and Active Suspension System
2 Definition:Suspension system: a mechanical system of springs and shock absorbers that connect the wheels and axles to the chassis of a wheeled vehicle
3 The Function of suspension system: The job of a car suspension are: - to carry the static weight of the vehicle - to maximize the friction between the tires and the road surface, - to provide steering stability with good handling (minimize body roll) - to ensure the comfort of the passengers (ability to smooth out a bumpy road).
4 The Function of Spring and Shock Absorber The Function of Spring: to absorb shock energy from road bump and convert it into potential energy of springThe Function of Shock Absorber: to dissipate shock energy from road bump without causing undue oscillation in the vehicle.
5 Classification of Suspension System PassiveSemi-Active- Orifice Based Damper- MR fluid based DamperActiveSlow ActiveFully Active
6 Passive SuspensionThe damping value (Cs) of a passive damper is determined by the total orifice area (the number of hole) in the piston head.
9 MR FluidMagnetorheological fluid is composed of oil and varying percentages of ferrous particles (20-50 microns in diameter) that have been coated with an anti-coagulant material.Varying the magnetic field strength has the effect of changing the viscosity of the magnetorheological fluid.
11 Active Suspension System Active suspension system uses hydraulic actuator to reduce the amount of external power necessary to achieve the desired performance characteristics and is able to exert an independent force on the suspension to improve the riding characteristics.
12 Schematic Diagram and Basic Configuration of Hydraulically Actuated Active Suspension System
16 Active VS Semi-Active Semi-Active: Lower implementation cost Lower power consumptionEasier to controlSimpler designEasy to installDisadvantage: damper constraint, the force range is limited, performance is not as good as active system
17 Active VS Semi-Active Active System: Wider range of force No force-velocity constraintCan achieve better performance (vehicle dynamics)Disadvantages: power consumption is high, higher weight to power ratio, expensive, major modification should be made before installing active system into the existing vehicle