Active suspension

A c t i v e S u s p e n s i o n S y s t e m | 1
CHAPTER 1
1. INTRODUCTION
1.1 SUSPENSION SYSTEM
Suspension is the term given to a system of springs, shock absorbers and
linkages that connects a vehicle to its wheels. Suspension systems serve a dual
purpose – contributing to the car’s roadholding / handling and braking for
good active safety and driving pleasure, and keeping vehicle occupants
comfortable and reasonably well isolated from road noise, bumps and
vibrations, etc. These goals are generally at odds, so the turning of suspension
involves finding the right compromises. It is important for the suspension to
keep the road wheel in contact with the road surface as much as possible,
because all the forces acting on the vehicle itself and any cargo or luggage
from damage and wear. The design of front and rear suspension of a car may
be different.
1.2 SUSPENSION DESIGN CONFLICTS
Design cornering the car’s tyres produce so-called slip forces in lateral
direction. These forces, displayed as horizontal arrows in figure 1 results in an
unfavorable deformation of the contact patch and a contour clockwise torque
around a horizontal axis through the car’s centre of gravity. Additional vertical
reaction forces, the vertical arrows in figure 2, counteracts the torque and
prevent the car from rolling over. In case of the car to further compress and on
the right side of the car to expand which causes some roll of the car’s body.
Depending on the geometry of the suspension links, the orientation of the
wheels with respect to the car’s body will change during suspension travel.

Figure 1: Slip Forces and Load Transfer Forces
In case of trailing arm geometry, the single suspension link connecting each
wheel to the chassis rotates along a lateral axis with respect to the chassis.
During cornering the tyres will therefore takes over the angle of the car’s
body, which also results in a deformation of the contact patch. This
combination leads to an undesirable contact patch, with a smaller area and a
non – homogenous pressure distribution, as is presented in figure
Figure 2: Contact Patch Deformation During Cornering
The trailing arm suspension will force the camber angle of the tyres to take
over the roll angle of the vehicle’s body. This characteristics is describes by
the value 10 /0 ( 10 camber / 0body roll). In case of cornering, it would be
desirable to have a suspension system that provides so – called counter –
camber (camber<0) during cornering: -10 /0. The negative camber angle will
result in a favorable deformation of the contact patch, which in combination
with the unfavorable deformation due to the slip forces will lead desirable
contact patch, as is displayed in figure 3.

Figure 3: Contact Patch Deformation During Cornering
Most of today’s suspension systems vary between 00 /0(rigid axle) and 00
/0(trailing arm). Examples are the double wishbone, the multi-link and the
McPherson suspension system. The absence of counter – camber suspension
system can be explained by the fact that such a suspension system will result
in extreme camber and therefore extreme tyre wear in case of encountering a
bump in the road or in the road or an extremely loaded car. This is visualized
in figure 4
Figure 4: Contact Patch Deformation When Encountering A Bump

Another method of improving cornering behavior is by means of introducing non –
zero static camber,
Figure 5: Contact Patch Deformation When Encountering a Bump
Usually all suspension systems other than 10 /0 –system will carry out a small
lateral movement during suspension travel because the links in the system
describe a circular arc. The lateral movement, displayed in figure 6 causes the
tyre to deform and result in extra tyre wear. This is prevented in case of 10 /0
system like a trailing arm suspension.
Figure 6: Lateral Movement During Suspension Travel

CHAPTER 2
2. LITERATURE REVIEW
During the last decades fuzzy logic has implemented very fast hence the first
paper in fuzzy set theory, which is now considered to be the influenced paper
of the subject, was written by Zadeh[5], who is considered the founding father
of the field. Then in 1975, Mamdani, developed Zadeh’s work and
demonstrated the variety of fuzzy logic control (FLC) for a small model steam
engine.
An active suspension system possesses the ability to reduce acceleration of
sprung mass continuously as well as to minimize suspension deflection, which
result in improvement of tyre grip with the road surface, thus; brake, traction
control and vehicle maneuverability can be considered improved.
Today’s a rebellious race is taking place among the automotive industry so as
to produce highly developed models. One of the performance requirements is
advanced suspension system which prevents the road distribution to affect the
passenger comfort while increasing riding capabilities and performing a
smooth drive. Replacement of the spring – damper suspension of automobile
by active suspension systems has the potential of improving safety and
comfort under nominal conditions.
In the recent past, it has been reported on this problem successively, about the
base of optimization techniques, adaptive control and even, H- infinity robust
methods. The use of active suspension system on road vehicles has been
considered for many years. A large number of different arrangements from
semi – active to fully – active schemes have been investigated. These has also
been interest in characterizing the degree of freedom and constraints involved
in active suspension design.

CHAPTER 3
3. OBJECTIVES:
1. The main objective is to reduce the discomfort sensed by
passengers.
2. To improve safety and isolate the vehicle from noise, vibrations and
road bumps.
3. To reduce the slip occurring at corner.

CHAPTER 4
4. METHODOLOGY
4.1 PROPERTIES OF SUSPENSION SYSTEM
4.11 SPRING RATE (OR SUSPENSION RATE)
The spring rate is a component in setting the vehicles ride height
or its location in the suspension stroke. Vehicles which carry
heavy loads will often have heavier springs to compensate for the
additional weight that would otherwise collapse a vehicle to the
bottom of its travel (stroke).Heavier springs are also used in
performance application where the loading condition experienced
are more extreme.
MATHEMATICS OF SPRING RATE
Spring rate is the ratio used to measure how resistant a spring is
to being compressed or expanded during the spring’s deflection
the magnitude of spring force increases as deflection increases
according to Hook’s Law. Briefly, this can be stated as
F = -- K x
Where,
F is the force the spring exerts.
K is the spring rate of the spring.
x is the displacement from equilibrium length ie. The length at
which the spring is neither compressed nor stretched.
The spring rate of a coil spring may be calculated by a simple
algebraic equation or it may be measured in a spring testing
machine. The spring constant k can be calculated as follows:
K = (d4G)/(8ND3)
Where d is the wire diameter, G is the spring’s shear modulus (eg:
about 12,000,000 ibf/in2 or 80 GPa for steel), and N is the number of
wraps and D is the diameter of the coil.

4.1.2 WHEEL RATE
Wheel rate is the effective spring rate when measured at the wheel.
This is as opposed to simply measuring the spring rate alone. Wheel
rate is usually equal to or considerably less than the spring rate.
Commonly, springs are mounted on control arms, swing arms or
some other pivoting suspension member.
4.1.3 ROLL COUPLE PERFORMANCE
Roll couple percentage is the effective wheel rate, in roll, of each
axle of the vehicle as a ratio of the vehicle’s total roll rate. Roll
couple percentage is critical in accurately balancing the handling of a
vehicle. It is commonly adjusted through the use of anti – roll bars,
but can also be changed through the use of different springs.
4.1.4 WEIGHT TRANSFER
Weight transfer during cornering, acceleration or braking is usually
calculated per individual wheels and compared with the static
weights for the same wheels.
The total amount of weight transfer is only affected by four factors:
The distance between wheel centers and height of the center of
gravity, the mass of the vehicle, and the amount of acceleration
experienced.
UNSPRUNG WEIGHT TRANSFER
Un-sprung weight transfer is calculated based on the weight of the
vehicle’s components that are not supported by the springs. This
includes tyre, wheels, spindles, half the control arm’s weight and
other components.
SPRUNG WEIGHT TRANSFER
Sprung weight transfer is the weight transferred by only the weight of
the vehicle resting on the springs, not the total vehicle weight.

4.1.5 JACKING FORCES
Jacking forces are the sum of the vertical forces components
experienced by the suspension links. The resultant forces acts to lift
the sprung mass if the roll center is above ground, or compress it if
underground. Gradually, the higher the roll center, the more jacking
force is experienced.
4.1.6 TRAVEL
Travel is the measure of distance from bottom of the suspension
stroke to the top of the suspension stroke. Bottoming or lifting a
wheel can cause severe control problems or directly cause damage,
“Bottoming “ can be caused by suspension, tyres, fenders, etc.
running out of space to move the body or other components of the car
hitting the road.
4.1.7 DAMPING
Damping is the control of motion or oscillation, as seen with the use
of hydraulic gates and valves in a vehicles in a vehicle shock
absorber. This may also vary, intentionally or unintentionally. Like
spring rate, the optimum damping for comfort may be less than for
control.
4.1.8 CLAMBER CONTROL
Camber control are due to the wheel travel, body roll and suspension
system deflection or compliance. In general, a tyre wears and brake
best at -1 to -20 of camber from vertical. Too much camber will result
in the decreasing of braking performance due to a reduced contact
patch size through excessive camber variation in the suspension
geometry. The amount of camber change in bumps is determined by
the instantaneous front view swing to camber inward when
compressed in bumps.

4.1.9 ROLL CENTER HEIGHT
This is important to body roll and to front to rear stiffness
distribution. However, the roll stiffness distribution in most car’s are
set more by the antiroll bars than the RCH. The height of the roll
center is reduced to the amount of jacking forces experienced.
4.1.10 ANTI - DIVE AND ANTI - SQUAT
Anti – drive and anti – squat are expressed in terms of percentage and
refers to the front driving under braking and the rear squatting under
acceleration. They can be thought of as the counterparts for braking
and acceleration as jacking forces are to cornering. The main reason
for the difference is due to the different design goals between front
and rear suspension, whereas suspension is usually symmetric
between the left and right of the vehicle.
4.1.11 ISOLATION FROM HIGH FREQUENCY
SHOCK
For most purposes, the weight of the suspension components is
unimportant, but at high frequencies, caused by road surface
roughness, the parts isolated by rubber bushing act as a multistage
filter to suppress noise and vibration better than can be done with
only the tyres and springs.( The springs works mainly in the vertical
direction.)
4.1.12 AIR RESISTANT (DRAG)
Certain modern vehicles have height adjustment suspension in order
to improve aerodynamics and fuel efficiency.

4.2 SUSPENSION PARTS
Figure 7: Parts of a suspension system
The suspension of a car is actually part of the chassis, which
comprises all of the important systems located beneath the car’s body. These
systems include:
1. The frame – Structural, load – carrying component that supports the car’s
engine and body, which are run in turn supported by the suspension.
2. The suspension system – setup that supports weight, absorbs and dampens
shock and helps maintain tyre contact.
3. The strreing system – mechanism that enables the driver to guide and direct
the vehicle.
4. And/or friction with the road.
4.2.1 FUNDAMENTAL COMPONENTS OF ANY
SUSPENSION
4.2.1.1 Springs.
4.2.1.2 Dampers.
4.2.1.3 Anti – sway bars.

4.2.1.1 SPRINGS
Today’s springing systems are based on one of four basic designs:
1. COIL SPRINGS – this is the most common type of springs and is, in
essence, a heavy- duty torsion bar coiled around an axis. Coil springs
compress and expand to absorb the motion of the wheels.
2. LEAF SPRING – this type of springs consists of several layers of metal
bound together to act as a single unit. Leaf springs were first used on horse
– drawn carriages and were found on most American automobiles until
1985. They are still used today on most trucks and heavy – duty vehicles.
3. TORSION BARS – torsion bars use the twisting properties of a steel bar to
provide coil – perpendicular to the torsion bar. When the wheel hits a
bumps.
4. Vertical motion is transferred to the wishbone and then, through the
levering action, to the torsion bar. The torsion spring like performance.
This is how they work: One end of a bar is anchored to the vehicle frame.
The other end is attached to a wishbone, which acts like a lever that moves
bar then twists along its axis to provide the spring force.
5. AIR SPRINGS – Air springs, which consist of a cylindrical chamber of air
positioned between the wheel and the car’s body, use the compressive
qualities of air to absorb wheel vibrations. The concept is actually more
than a century old and could be found on horse – drawn buggies. Air
springs from the era were made from air – filled, leather diaphragms, much
like a bellows; they were replaced with molded- rubber air springs in the
1930’s.
4.2.1.2 DAMPERS, SHOCK ABSORBERS
Unless a dampening structure is present, a car spring will extend and
release energy it absorbs from a bump at an uncontrollable rate. The spring
will continue to bounce at it’s natural frequency until all of the energy
originally put into it is used up. A suspension built on springs alone would

make for an extremely bouncy ride and, depending on the terrain, an
uncontrollable car.
Enter the shock absorber, or snubber, a device that controls unwanted
spring motion through a process known as damping. Shock absorbers slow
down and reduce the magnitude of vibratory motions by turning the kinetic
energy of suspension movement into heat energy that can be dissipated
through hydraulic fluid.
A shock absorber is basically an oil pump placed between the frame of the
car and the wheels. The upper mount of the shock absorber connects to the
frame (ie: the sprung weight), while the lower mount connects to the axle,
near the wheels (ie: the unsprung weight ). In a twin – tube design, one of
the most common types of shock absorbers, the upper mount is connected
to a piston rod, which is turn is connected to a piston, which in turn sits in
a tube filled with hydraulic fluid. The inner tube is known as the pressure
tube, and the outer tube is known as the reverse tube. The reverse tube
stores excess hydraulic fluid. When the car wheel encounters a bump in
the road and causes the spring to coil and uncoil, the energy of the spring
is transferred to the shock absorber through the upper mount, down the
piston rod into the piston. Orifices perforate the piston and allow fluid to
leak through as the piston moves up and down in the pressure tube.
Because the orifice are relatively tiny, only a small amount of fluid, under
great pressure, passes through. This slows down the piston, which in turn
slows down the spring.
Shock – absorbers work in two cycles – the compression cycle and the
extension cycle. The compression cycle occurs as the piston moves downwards,
compressing the hydraulic fluid in the chamber below the piston. The extension cycle
occurs as the piston moves towards the top of the pressure tube, compressing the fluid
in the chamber above the piston. A typical car or light truck will have more resistance
during its extension cycle than its compression cycle. With that in mind, the
compression cycle controls the motion of the vehicle’s unsprung weight, while
extension controls the heavier, sprung weight
.

4.2.1.3 ANTI – SWAY BARS
Anti- sway bars (anti – sway bars) are used along with shock absorbers or
struts to give a moving automobile additional stability. An anti – sway bar
is a metal rod that spans the entire axle and effectively joins each side of
the suspension together causing movement to the other wheel. This creates
a more level ride and reduces vehicle sway. In particular, it combats the
roll of a car on its suspension as it corners. For this reason, almost a cars
today are fitted with anti – sway bar as standard equipment, although if
they’re not, kits make it easy to install the bars at any time.
4.3. ACTIVE SUSPENSION
During the design of a suspension system, a number of conflicts
requirement has to be met. The suspension setup has to ensure a
comfortable ride and good cornering characteristics at the same time. Also,
optimal contact between wheels and road surface is needed in various
driving conditions in order to maximize safety. Instead of a passive
suspension, present in most of today’s car’s, an active suspension can be
used in order to better resolve the trade – off between these conflicts.
However, this is generally accomplished by considerable energy
consumption. An active suspension is capable of leveling the car during
cornering theoretically without consuming energy. Simulations using a full
– car model shows that this maximizes the car’s cornering velocity. As
extreme cornering may be required to remain on the road or to avoid an
obstacle, implementing the active suspension system improves safety.
As the active part of the suspension takes care of realizing good cornering
behavior and of static load variations, the primary suspension springs can
be tuned purely for optimizing comfort and road holding. Simulations show
that the required energy for leveling the car during cornering is negotiable,
so it can be concluded that the active suspension system is able to
economically level the car. The active suspension’s potential for improving
comfort is examined using a quarter – car model in combination with the
skyhook damping principle performing simulations with an unrestricted

actuator shows that comfort can slightly be improved with little actuator
action and without deteriorating road holding and suspension travel.
Further improving the comfort level requires more actuator action and
results in considerable degradation of road holding and suspension travel.
4.3.1 DEVELOPMENT OF ACTIVE SUSPENSION
SYSTEM
The basic idea in active control of suspensions is to use an active element (
the actuator, eg: a hydraulic cylinder ) to apply a demand force between
the vehicle and the wheel. The active suspension system require several
components such as AC’s servo valves, high pressure tanks for the control
fluid, sensors for detecting the system, etc.
Chiou et al designed a fuzzy logic controller (FLC) for an active
automobile suspension system in which the membership functions and
control rules were optimized using a genetic algorithm (GA). The
objective of the FLC was to strike an optimal balance between the ride
comfort and the vehicle stability. The value of the crossover and mutation
parameters in the GA were adapted dynamically during the convergence
procedure using a fuzzy control scheme. The GA – assisted FLC controller
not only reduces the suspension deflection , sprung mass acceleration, and
beating distance between the tyre and the ground relative to that observed
in a passive suspension system, but also provides a noticeable improved
ride comfort and vehicle stability compared to that obtained when using a
conventional optimal linear feedback control method.
4.4. WORKING
The major components of an active suspension system are a linear actuator,
a microcontroller, and a sensor system that will allow us to monitor the
displacement velocity, and acceleration an input wave will be sent into the
system, via the microcontroller, and the platform will move according to
the type of wave with different options available for the user to control.
This actuator will be controlled using a microcontroller. The display will

show the maximum velocity and acceleration of the actuator, and the type
of motion that is undergoing (ie. up and down. Sensor will permit
monitoring and recording of the platform motion.
Figure 8: Active Suspension Components
The parts that will be used to create the active suspension system are liner actuator,
one motion sensor, a microcontroller, a keypad and a display. Since no hydraulic
fluids will be permitted electrically driven linear actuator will be utilized. A low
voltage linear actuator has been chosen because high voltage could be potentially
dangerous to the design engineers. The rated speed of the actuator at full power is 0.5
in. The user will input the desired motion on the keypad. Information will be
interpreted by the microcontroller and will cause the linear actuator to move a certain
distance. The sensors will sense any motion made by the platform and report it to the
microcontroller. After that the microcontroller will process the signal from the sensor
and show the measurement on the display.
4.5. ACTIVE SUSPENSION DESIGN
4.5.1 CONTROLLER DESIGN
In this section, a controller will be designed which regulates the adjustable
arm’s angle and therefore the force produced by the active suspension. The
control of the suspension system takes place in two stages. In the first
stage a performance improvement controller determines the force that has

to be produced by the active suspension for leveling the car, comfort
improvement, wheel load variation reduction, suspension travel reduction
or a combination of these improvements. The required force functions as
input for the actuator controller. In the second stage an actuator controller
makes sure that the required force is produced as possible. The actuator is
capable that the force stays within these limits. Using the mathematical
model, this limited required force is converted to an angle at which the
actually produces this force. This angle is called the reference angle.
Hereafter, the actuator controller drives the adjusting arm, via a moment
applied by an electric actuator, to the reference angle using a PD –
controller with a correction for the estimated disturbance is caused by the
reaction moment and can be predicted by the mathematical model. The
actuator controller components are visualized.
Figure 9: Schematic Representation of Controller
4.5.2 SOFTWARE DESIGN
The active suspension system contains both software and hardware design.
For the software portion, there are these 3major portions of code: The
motion module, Calculation module, and the Interaction module. There
will be many smaller modules involved but these are the main groups. The
motion module contains the software programs that provide the linear
actuator with the necessary commands to make the platform move up and
down. The calculation module obtains data and uses that data to calculate

the distance moved by the platform, the acceleration, and the velocity at
the centroid of the platform. The interaction module contains a module to
initialize the LCD display, a module to display prompts to the user and a
module that will interpret the user input. The input will then be processed
and the appropriate module will be executed.
If the input entered recognized, a program is chosen; if not an error
message is displayed. If the platform is unable to perform the requested
motion an error message will also be displayed. Regardless of which input
is selected, the software modules follow the same sequence of commands.
But the platform will perform different movements depending on which
type of input is selected. If a sinusoidal input is entered the platform will
move in a continuous motion up and down in relation to the input data
entered about the amplitude and frequency. A step input will make a single
step up whereas a square wave make steps up and down in relation to the
amplitude and frequency. The sensor, which is integrated with the actuator
hardware, will obtain the linear position of the platform and store the
position in another variable. This variable will be used in calculation to
compute the distance moved by the platform, the acceleration, and the
velocity at the centroid of the platform.
When the microcontroller is first started, the platform will start at an
initial position.
The platform will move the desired distance entered by the used and then
moves to the initial position entered by the user and waits for another
instruction from the user. When another desired motion is entered, the
platform will return to the initial position and then perform the desired
motion

Figure 10: Software Flow Chart
4.5.3 HARDWARE DESIGN
A block diagram with the necessary hardware is shown below. A sine
wave, square wave, or step wave will be fed to the input to provide a range
of motion that can be selected. The actuator will give move in accordance
with what is selected. A maximum and minimum height will be designated
for a range of motion to keep the platform from exceeding its limits. For a

sine wave, the platform will be raised to the center of the range of motion
and then begin to move. For the other input waveforms, the starting point
will be the lowest possible point in the range of motion.
Figure 11: Hardware Flowchart
4.6 FUNCTIONS OF ACTIVE SUSPENSION
1. Improves driver control, safety and stability, with or without a load.
2. Eliminates sway and reduces roll on corners.
3. Reduces axle wrap.
4. Maximum safety.
5. Absorbs load, rather than resisting it, thereby ensuring a much more
comfortable ride.
6. Eliminates the need for fitting extra blades which harden the ride.

7. Better handling and control in windy and rough road conditions.
8. Minimize wear on tires, shocks, shackles and leaf springs.
4.7 BOSE SUSPENSION SYSTEM
The car suspension system has two goals: passenger comfort and vehicle
control.
Comfort can be derived from negating the feel of road disturbances to the
passengers.
Vehicle control can be achieved by keeping the car body from rolling and
pitching too much and maintaining a good contact between the tire and the
road. But these goals are difficult to achieve as passenger comfort and
vehicle control are always in conflict.
The suspension system of a a luxury car is often designed with an eye on
passenger comfort, but the outcome of it is a vehicle that rolls and pitches
while driving, turning and braking. Sports cars are designed with emphasis
on control; so the suspension is designed to reduce roll and pitch where
comfort has to be sacrificed. In 1980, Dr. Bose conducted a mathematical
study to determine the optimum possible performance of an automotive
suspension, ignoring the limitations of any existing suspension hardware.
The result of this 5-year study indicated that it was possible to achieve
performance that was a large step above anything available. After
evaluating conventional and variable spring/damper system as well as
hydraulic approaches, it was determined that none had the combination of
speed, strength and efficiency that it necessary to provide the desired
results. The study led to electromagnetics as the approach that could realize
the desired suspension characteristics. The bosh suspension required
significant advancements in four key disciplines; linear electromagnetic
motors, power amplifiers, control algorithms and computation speed. Bose
took on the challenge of the first three disciples and bet on developments
that industry would make on the fourth items.
Prototypes of the Bose suspension have been installed in standard
production vehicles. These research vehicles have been tested on a wide
variety of roads, on tracks and on durability courses.

4.7.1 LINEAR ELECTOMAGNETIC MOTOR
A linear electromagnetic motor is installed at each wheel of a Bose
equipped vehicle. Inside the linear electromagnetic motor are magnets and
coils of wire. When electrical power is applied to the coils, the motor
responds quickly enough to counter the effects of bumps and potholes,
maintaining a comfortable ride. Additionally, the motor has been designed
for maximum strength in a small package, allowing it to put out enough
force to prevent the car from rolling and pitching during aggressive driving
maneuvers.
Figure 12: Bose suspension front module, picture Bose.
4.7.2 POWER AMPLIFIER
The power amplifier delivers electrical power to the motor in response to
signals from the control algorithms. The amplifiers are based on switching
amplification technologies pioneered by Dr. Bose at MIT in the early
1960’s- technologies that led to the founding of Bose co-orporation in
1964. The regenerative power amplifiers allow power to flow into the
linear electromagnetic motor and also allow power to be returned from the
motor. For example, when the Bose suspension encounter a pothole, power
is used to extend the motor and isolate the car’s occupants from the
disturbance. On the far side of the pothole, the motor operates as a

generator requires less than a third of the power of a typical car’s air
conditioning system.
Figure 13: Bose suspension system
4.7.3 BENEFITS OF BOSE SUSPENSION SYSTEM
1. Superior comfort
2. Superior control
3. Reduced body roll during turns
4. Reduced need for camber roll during turns
5. Requires only 1/3 of the power needed by the AC
6. Wider damping range that Magneto- Rheological system
4.7.4 APPLICATIONS
1. System will be offered on high end luxury vehicles.
2. The same technology has been applied in Military applications.
4.8 RECENT DEVELOPENTS
4.8.1 PIEZO TEMS
A new electrical controlled suspension system called Piezo TEMS (Toyota
electrical modulated suspension system) is developed by using
piezoelectric ceramics for a sensor, and an actuator. As a result, good
drivability and vehicle stability can be obtained with an improved riding
comfort.

CHAPTER 5
6. CONCLUSION
Usually the suspension consists of passive force element which are designed
to optimize the trade-off between ride comfort, suspension travel and wheel
load variation. Also, the geometry design of the suspension links is a trade-off
between optimal orientation of the wheels in case of bumps in the road or
during cornering. Furthermore, the springs should be stiff enough to avoid
exaggerate body roll or pitch during cornering, acceleration and braking.
Moreover, they are complex and space consuming. The additional elements of
an active suspension system are able to produce forces when required and
therefore the trade-off between ride comfort, suspension travel and wheel load
variation can be better resolved. Furthermore, an active suspension system can
be used in order to eliminate body roll during cornering. As a result, the
complicated and space consuming suspension links can be replaced with a
compact and simple trailing arm suspension. Also, static load variation can be
taken care of by adjusting the stiffness of the suspension system. It can be
adjusted to the driving situation and to individualize the handling
characteristics and comfort level of the vehicle.

CHAPTER 6
7. REFREENCE
 “ An active suspension system capable of economically leveling a
car during cornering”
A journal by MSP LEEGWATER DCT-2007 087. EINDHOVER
University of Technology, the Dept. of Netherlands- (2007).
 “The future Development and Analysis of Vehicle Active
suspension system”: Nouby M, Ghazaly and Ahmed O. Moaaz:
IOSR journal of mechanical engineering- (2014).
 “Design and manufacturing of an Adaptive Suspension System”, A
Major Qualifying Project Report Submitted to the faculty of
WORCESTER POLYTECHNIC INSTITUTE; Michael Gifford,
Tanner Landis & Cody Woods- MECHANICAL ENGINEERING-
(2015).

Active suspension

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