MAE 442 (Active Suspensions)

Active Suspension Systems

Anthony GriffinBradley Rouse

Philip Woodward

MAE 442Dr. Klang5/6/2005

Outline

Common Types of Suspensions

Active Suspensions Benefits Disadvantages Applications Conclusion

Common Suspensions

Front Suspension Solid I-Beam Twin I-Beam MacPherson Strut Short-Long Arm

Rear Suspension Non Independent

Rear Leaf Springs Non Independent

Rear Coil Springs Trailing Arm Beam

Solid I-Beam

Used on trucks and other large vehicles

Economical Simple design Low Maintenance Excellent load capacity Non-independent design Uncomfortable ride

quality Poor handling

Twin I-Beam

Found on many Ford trucks

Forged, cast, or stamped axles

Excellent load capacity Requires special

equipment for alignment adjustments

MacPherson Strut

One of the most popular systems

One Control Arm Ideal for front wheel

drive Light weight Economical Good ride quality and

handling characteristics Used for both front and

rear suspensions

Short-Long Arm

Independent design Uses an upper and a

lower control arm Uses either torsion

bars or coil springs Good ride quality and

handling characteristics

Heavy and complex design requires a lot of space

Rear Leaf Springs

Non-independent design

Similar to front solid I-beam axle

Large load carrying capacity

Rear Coil Springs

Non-independent design

Uses coils and control arms instead of leaf springs

Good load carrying capacity

Trailing Arm

Independent Design Uses individual

lower control arms Uses coil springs

and shocks Good ride quality

Rear Beam

Non-independent design

Stamped beam axles

Uses coil springs and trailing arms

Light and simple design

Active Suspension Systems

Bose Suspension Magneto-Rheological Technology

Bose Suspension System

Electromagnetic 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 System

Uses sensor measurements to instantaneously counteract road forces

Produces excellent ride quality and superior control in the same system

Bose Suspension Components

Linear Electromagnetic Motor Responds quickly enough to counter the effects of bumps and road

irregularities Power Amplifier

Sends power to the motor during extension and returns power during retraction

Control Algorithms Observe sensor measurements and send commands to the power

amplifiers

Bose vs. Stock Suspension

Magneto-Rheological Technology

Dampers contain magnetic particles suspended in fluid

Magnetic field within the fluid aligns particles Creates resistance to movement and

increases damping Variable magnetic field creates more or less

resistance as needed System can change up to 1000 times per

second

Benefits

Bose Suspension Superior comfort Superior control Reduces body roll during

turns Reduces need for camber

roll during turns Requires only 1/3 of the

power needed by the AC Wider damping range than

Magneto-Rheological systems

Magnetic Ride Control Improved road handling Improved wheel control Smoother ride than

conventional shocks and struts

Reduces noise and virbations

Continuous range of damping

Disadvantages

High initial cost High repair costs Complex systems

Applications

Bose Suspension System will be offered

on high end luxury vehicles within the next 5 years.

The same technology has been applied in Military applications.

Magnetic Ride Control Currently offered on

Cadillac SRX and Seville STS models.

Offered on the Chevrolet Corvette for the 2003 model year.

Mercedes S600 BMW 7 series

Active Military Application

Conclusion

Active 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.