MAE 442 (Active Suspensions)

Active Suspension SystemsAnthony GriffinBradley RousePhilip WoodwardMAE 442Dr. Klang5/6/2005

OutlineCommon Types of SuspensionsActive SuspensionsBenefitsDisadvantagesApplicationsConclusion

Common SuspensionsFront SuspensionSolid I-BeamTwin I-BeamMacPherson StrutShort-Long ArmRear SuspensionNon Independent Rear Leaf SpringsNon Independent Rear Coil SpringsTrailing ArmBeam

Solid I-Beam

Used on trucks and other large vehiclesEconomicalSimple designLow MaintenanceExcellent load capacity Non-independent designUncomfortable ride qualityPoor handling

Twin I-BeamFound on many Ford trucksForged, cast, or stamped axlesExcellent load capacityRequires special equipment for alignment adjustments

MacPherson StrutOne of the most popular systemsOne Control ArmIdeal for front wheel driveLight weightEconomicalGood ride quality and handling characteristicsUsed for both front and rear suspensions

Short-Long ArmIndependent designUses an upper and a lower control armUses either torsion bars or coil springsGood ride quality and handling characteristicsHeavy and complex design requires a lot of space

Rear Leaf SpringsNon-independent designSimilar to front solid I-beam axleLarge load carrying capacity

Rear Coil Springs

Non-independent designUses coils and control arms instead of leaf springsGood load carrying capacity

Trailing ArmIndependent DesignUses individual lower control armsUses coil springs and shocksGood ride quality

Rear BeamNon-independent designStamped beam axlesUses coil springs and trailing armsLight and simple design

Active Suspension SystemsBose Suspension

Magneto-Rheological Technology

Bose Suspension SystemElectromagnetic motors at each wheel instead of traditional shocks and struts.Sensors at various locations to detect body and suspension movement.Comparison of Factory-Installed and Bose Suspensions: Body Motion on Bump Course

Bose Suspension SystemUses sensor measurements to instantaneously counteract road forcesProduces excellent ride quality and superior control in the same system

Bose Suspension ComponentsLinear Electromagnetic Motor Responds quickly enough to counter the effects of bumps and road irregularitiesPower AmplifierSends power to the motor during extension and returns power during retractionControl AlgorithmsObserve sensor measurements and send commands to the power amplifiers

Bose vs. Stock Suspension

Magneto-Rheological TechnologyDampers contain magnetic particles suspended in fluidMagnetic field within the fluid aligns particles Creates resistance to movement and increases dampingVariable magnetic field creates more or less resistance as needed System can change up to 1000 times per second

BenefitsBose SuspensionSuperior comfortSuperior controlReduces body roll during turnsReduces need for camber roll during turnsRequires only 1/3 of the power needed by the ACWider damping range than Magneto-Rheological systems

Magnetic Ride ControlImproved road handling Improved wheel controlSmoother ride than conventional shocks and strutsReduces noise and virbationsContinuous range of damping

Disadvantages

High initial costHigh repair costsComplex systems

ApplicationsBose SuspensionSystem will be offered on high end luxury vehicles within the next 5 years.The same technology has been applied in Military applications.

Magnetic Ride ControlCurrently offered on Cadillac SRX and Seville STS models.Offered on the Chevrolet Corvette for the 2003 model year.Mercedes S600BMW 7 series

Active Military Application

ConclusionActive control suspensions offer a wider range of comfort and control than most current suspension systems.Offers unmatched vehicle handling performance.May eventually find their way into more common production vehicles.