Suspension system is the most significant part which heavily affects the vehicle handling performance and ride quality. Because of its structures limit, the passive suspension system can hardly improve the two properties at the same time. Since the advent of active suspension system, it has become the research hot spot. In this review paper we shall see the advantages of the active suspension system over the passive suspensions systems and its incorporation in passenger vehicles.

1. Simulation and Dynamic Analysis of Active
Suspension System
Sr. No. Name Enrollment no.
1 Ashishkumar Jain 130950119040
2 Gunjankumar Jain 130950119027
3 Akshay Patel 130950119071
4 Bhargav Patel 130950119072
Guided by : Jay .N. Mandalia
Assistant Professor
1

2. Flow Of Presentation
1. Objective of Project.
2. Literature Survey.
3. Introduction of Project with Block Diagram.
4. Introduction of Passive Suspension system.
5. List of Component for Passive Suspension system.
6. Simulation and Result for Passive Suspension System.
7. Introduction for Active Suspension System.
8. List of Components for Active Suspension System with Technical Specification.
9. Simulation and Result for Active Suspension System.
10. Comparison – Passive & Active Suspension System.
11. Work Schedule with Future Plan.
12. References.
2

3. Objective Of Project
1. Maintain correct vehicle ride height
2. Reduce the effect of shock forces
3. Maintain correct wheel alignment
4. Support vehicle weight
5. To maintain continuous traction between wheel and Road
6. Reduction in body roll and pitching of the chassis
7. Increase in ride comfort and vehicle stability
8. Reduction in overall vibration of the body parts which results in increasing
the life expectancy of the vehicle
3

4. Literature Survey
1. Dr. Pushpendra Sharma et.al, gave a comparison of deflection of existing car
with the existing suspension system with the modified suspension system and
found out the deflection of modified design.
2. Michele leluzzi et.al, developed a control software and tested it in a real
prototype truck for semi-active suspension system. The results confined
improvement in driver comfort and better handling of truck behavior.
3. Sergio M. Savaresi et.al, designed and analyzed control strategy for semi active
suspension in road vehicle using Mix SH-ADD algorithm and also developed to
control this ECU by using only 1-accelerometer sensor for semi-active
suspension system.
4. Katerina Hyniova et.al designed active suspension using linear electric model
in which his aspect was energy demand of the system. He carried out
experiments at different road condition and came to a result that it is possible to
change energy demands according to the road situation and the status of the
energy stored in the car (battery or super capacitor).
4

5. 5. Hyo-Jun kim et.al developed the road-sensing system and its application to
active suspension system using preview road information to improve stability
and control of car and he has given the road-sensing system which can robustly
reconstruct the road input profiles from the intermixed data with the vehicle’s
dynamic motion, is implemented using the composite-sensor system with the
optimally shaped transfer function.
6. Rahul .N. Sandage et al developed a mathematical model of semi – active
suspension system with 2DOF and is compared with different control system.
Fuzzy PID is better then PID controller and adaptation with MR damper gives
better results.
7. G. Priyandoko et al developed 4 control loops PI, AFC, Skyhook and PID on
MATLAB Simulink for active suspension system and it results of simulation are
compared with passive suspension system, PID and SANAFC (Skyhook
Adaptive Neuro Active for Control). Proving superiority of SANAFC.
8. Qi Zhou, developed the mathematical model for passive and active suspension
system and simulated them with different road inputs with different control
theories and also developed his own control theory. The author emphasized on
the feasibility of the new theory proposed by hin and its future promise. 5

6. 9. Mohamed Shalabi et al, works on the development of spring which uses air for
variation in the spring stiffness. The results shows that it reduces the natural
frequency of system by 0.92 and its amplitude by 0.762. adjustment of spring
stiffness is achieved by utilizing solenoid ON/OFF valve controlled through
microprocessor.
10. Harzil M. Isa et al, compared the different electromagnetic suspension system
i.e. passive EMS, semi – active EMS, active EMS. The results shows that the
power consumption for passive EMS is far very low compared to semi – active
and fully active electromagnetic suspension system. Although the comfort for
the passenger is increased more in fully active system compared to the other
three.
6

7. Introduction Of Project With Block Diagram
Simulation and Dynamic
analysis of Active
Suspension System
Present
Suspension
System
Literature
Review
Parameters
Identification for
Passive Suspension
System
Parameters Definition
For Passive
Suspension System
Modeling of
Passive
Suspension
System
Simulation and
Analysis of Passive
Suspension System
Parameters
Identification for
Active Suspension
System
Component
Identification for
Active
Suspension
System
Modeling of Active
Suspension System
Simulation and Analysis of
Active Suspension System
Result and its Comparison
with Passive Suspension
System
Conclusi
on
References
7

8. Passive Suspension System
• When we refer to a traditional or a conventional suspension system, we mean a
system that comes "as is." In other words, a conventional system is a passive
system. Once it's been installed in the car, its character changes very little.
• This has certain advantages and disadvantages. On the plus side, the system is
very predictable. Over time, you will develop a familiarity with your car's
suspension. You will understand its capabilities and its limitations. On the down
side, once the system has reached these limits, it has no way of compensating for
situations beyond its design parameters. Thus shock absorbers bottom out, struts
overextend, springs respond sluggishly, torsion bars get tweaked.
• In the car model which we have taken as a reference we use Macpherson Strut
suspension system in the front and Torsion Beam suspension system in the rear.
8

9. Parameters Definition for Passive Suspension
System
• Parameters for full car
• Sprung mass ms = 1274kg
• Unsprung mass mu = 141kg
• Spring stiffness for front ksf = 54.74
N/mm
• Spring stiffness for rear ksr = 68.43 N/mm
• Tire stiffness kt = 210 N/mm[1]
• Damping Co-efficient cs = 0.4 Ns/mm[2]
• Road displacement Zr
• Unsprung mass displacement Zu
• Sprung mass displacement Zs 9

10. • Components Of
Front Suspension
System
1. Spring.
2. Damper.
3. Tire.
1
2
3
List Of Component For Passive Suspension System
10

11. • Components of
Rear Suspension
1. Damper.
2. Spring
3. Tire
4. Torsion Beam
1
2
3
4
11

12. Simulation And Results For Passive Suspension System
Camber Angles
• Camber angle is the angle made by the wheels of a
vehicle; specifically, it is the angle between the
vertical axis of the wheels used for steering and the
vertical axis of the vehicle when viewed from the
front or rear. It is used in the design of steering and
suspension.
• Camber angle experiences changes during different
conditions while travelling.
1. Bumping condition.
2. Rolling condition.
3. Steering condition.
simulation of all the conditions are as followed
12

13. Camber Angle Variation for Bump Condition
BUMP
TRAVE
L (mm)
FRONT
L.H.S
(deg)
FRONT
R.H.S
(deg)
REAR
L.H.S
(deg)
REAR
R.H.S
(deg)
60.00 0.2527 0.2527 0.0000 0.0000
40.00 0.1097 0.1097 0.0000 0.0000
20.00 0.0914 0.0914 0.0000 0.0000
0.00 0.1834 0.1834 0.0000 0.0000
-20.00 0.3748 0.3748 0.0000 0.0000
-40.00 0.6575 0.6575 0.0000 0.0000
-60.00 1.0258 1.0258 0.0000 0.0000
13

14. ROLL
ANGLE
(deg)
FRONT
L.H.S
(deg)
FRONT
R.H.S
(deg)
REAR
L.H.S
(deg)
REAR
R.H.S
(deg)
3.00 3.1094 -2.3450 2.1142 -2.1284
2.50 2.5904 -1.9479 1.7629 -1.7728
2.00 2.0846 -1.5415 1.4112 -1.4175
1.50 1.5914 -1.1255 1.0591 -1.0626
1.00 1.1104 -0.6996 0.7065 -0.7080
0.50 0.6412 -0.2634 0.3535 -0.3538
0.00 0.1834 0.1834 0.0000 0.0000
-0.50 -0.2634 0.6412 -0.3539 0.3534
-1.00 -0.6996 1.1104 -0.7081 0.7064
-1.50 -1.1255 1.5914 -1.0627 1.0589
-2.00 -1.5415 2.0846 -1.4177 1.4110
-2.50 -1.9479 2.5904 -1.7730 1.7627
-3.00 -2.3450 3.1094 -2.1287 2.1139
Camber Angle for Rolling Condition
14

15. Camber Angle variation for Steering Condition
STEER
TRAVE
L
(mm)
FRONT
L.H.S
(deg)
FRONT
R.H.S
(deg)
REAR
L.H.S
(deg)
REAR
R.H.S
(deg)
30.00 1.03 0.03 0.00 0.00
25.00 0.84 0.01 0.00 0.00
20.00 0.66 0.01 0.00 0.00
15.00 0.51 0.03 0.00 0.00
10.00 0.38 0.06 0.00 0.00
5.00 0.27 0.11 0.00 0.00
0.00 0.18 0.18 0.00 0.00
-5.00 0.11 0.27 0.00 0.00
-10.00 0.06 0.38 0.00 0.00
-15.00 0.03 0.51 0.00 0.00
-20.00 0.01 0.66 0.00 0.00
-25.00 0.01 0.84 0.00 0.00
-30.00 0.03 1.03 0.00 0.00 15

16. Castor Angles
• The caster angle or castor angle is the angular displacement
of the steering axis from the vertical axis of a steered wheel
in a car, motorcycle, bicycle or other vehicle, measured in
the longitudinal direction.
• Camber angle experiences changes during different
conditions while travelling.
1. Bumping condition.
2. Rolling condition.
3. Steering condition.
simulation of all the conditions are as followed
16

17. Castor Angle variation for bump condition
BUMP
TRAVEL
(mm)
FRONT
L.H.S/R.H.S
(deg)
REAR
L.H.S/R.H.S
(deg)
60.00 2.6339 0.0000
40.00 2.5716 0.0000
20.00 2.5279 0.0000
0.00 2.5008 0.0000
-20.00 2.4887 0.0000
-40.00 2.4904 0.0000
-60.00 2.5051 0.0000
17

18. Castor Angle Variation for Rolling Condition
ROLL
ANGLE
(deg)
FRONT
L.H.S
FRONT
R.H.S
REAR
L.H.S
REAR
R.H.S
3.00 2.5410 2.5233 0.0000 0.0000
2.50 2.5294 2.5156 0.0000 0.0000
2.00 2.5199 2.5094 0.0000 0.0000
1.50 2.5123 2.5048 0.0000 0.0000
1.00 2.5066 2.5018 0.0000 0.0000
0.50 2.5028 2.5005 0.0000 0.0000
0.00 2.5008 2.5008 0.0000 0.0000
-0.50 2.5005 2.5029 0.0000 0.0000
-1.00 2.5019 2.5067 0.0000 0.0000
-1.50 2.5050 2.5125 0.0000 0.0000
-2.00 2.5096 2.5201 0.0000 0.0000
-2.50 2.5159 2.5297 0.0000 0.0000
-3.00 2.5236 2.5413 0.0000 0.0000
18

19. Castor Angle Variation for Steering Condition
STEER
TRAVEL
(mm)
FRONT
L.H.S/R.H.
S
(deg)
REAR
L.H.S/R.H.
S
(deg)
30.00 2.500 0.0000
25.00 2.500 0.0000
20.00 2.500 0.0000
15.00 2.500 0.0000
10.00 2.500 0.0000
5.00 2.500 0.0000
0.00 2.500 0.0000
-5.00 2.500 0.0000
-10.00 2.500 0.0000
-15.00 2.500 0.0000
-20.00 2.500 0.0000
-25.00 2.500 0.0000
-30.00 2.500 0.0000 19

20. Toe Angles
• In automotive engineering, toe, also known as
tracking, is the symmetric angle that each
wheel makes with the longitudinal axis of the
vehicle.
• Toe angle experiences changes during
different conditions while travelling.
1. Bumping condition.
2. Rolling condition.
3. Steering condition.
simulation of all the conditions are as
followed
20

21. Toe Angle Variation for Bump Condition
BUMP
TRAVEL
(mm)
FRONT
L.H.S/R.H.S
(deg)
REAR
L.H.S/R.H.S
(deg)
60.00 0.7634 0.0000
40.00 0.4396 0.0000
20.00 0.1904 0.0000
0.00 0.0000 0.0000
-20.00 -0.1459 0.0000
-40.00 -0.2610 0.0000
-60.00 -0.3588 0.0000
21

22. Toe Angle Variation for Rolling Condition
ROLL
ANGLE
(deg)
FRONT
L.H.S
FRONT
R.H.S
REAR
L.H.S
REAR
R.H.S
3.00 0.4475 -0.2687 0.2474 -0.3192
2.50 0.3558 -0.2317 0.2110 -0.2608
2.00 0.2717 -0.1923 0.1727 -0.2045
1.50 0.1945 -0.1499 0.1324 -0.1503
1.00 0.1239 -0.1041 0.0903 -0.0982
0.50 0.0592 -0.0543 0.0461 -0.0481
0.00 0.0000 0.0000 0.0000 0.0000
-0.50 -0.0543 0.0592 -0.0481 0.0461
-1.00 -0.1041 0.1239 -0.0982 0.0903
-1.50 -0.1499 0.1945 -0.1503 0.1324
-2.00 -0.1923 0.2717 -0.2045 0.1727
-2.50 -0.2317 0.3558 -0.2608 0.2110
-3.00 -0.2687 0.4475 -0.3192 0.2474 22

23. Toe Angle Variation for Steering Condition
STEER
TRAVEL
(mm)
FRONT
L.H.S
(deg)
FRONT
R.H.S
(deg)
REAR
L.H.S
(deg)
REAR
R.H.S
(deg)
30.00 12.70 12.70 0.0000 0.0000
25.00 10.50 10.50 0.0000 0.0000
20.00 8.34 8.34 0.0000 0.0000
15.00 6.22 6.22 0.0000 0.0000
10.00 4.12 4.12 0.0000 0.0000
5.00 2.05 2.05 0.0000 0.0000
0.00 0.00 0.00 0.0000 0.0000
-5.00 -2.03 -2.03 0.0000 0.0000
-10.00 -4.05 -4.05 0.0000 0.0000
-15.00 -6.06 -6.06 0.0000 0.0000
-20.00 -8.06 -8.06 0.0000 0.0000
-25.00 -10.05 -10.05 0.0000 0.0000
-30.00 -12.04 -12.04 0.0000 0.0000 23

24. Mathematical Model Of Passive Suspension System
24

25. Simulink Model Of Passive Suspension System
25

26. 26
Simulink graph for rolling condition

27. Active Suspension System
• An active suspension system, on the other hand, has the capability to adjust itself
continuously to changing road conditions.
• It artificially extends the design parameters of the system by constantly monitoring
and adjusting itself, thereby changing its character on an ongoing basis. With
advanced sensors and microprocessors feeding it information all the time, its
identity remains fluid, contextual and amorphous. By changing its character to
respond to varying road conditions, active suspension offers superior handling,
road feel, responsiveness and safety.
27

28. List Of Component For Active Suspension System
• List of Components
1. Hydraulic Actuators.
2. Electric Controller Unit (ECU)/PID Controller
3. Acceleration Sensors.
4. Level Sensor/vertical acceleration sensors
5. Steering wheel sensors.
6. Wheel speed sensors
28

29. 1. Hydraulic Actuators : -
• Hydraulic Actuators, as used in industrial process control
also in active suspension system employ hydraulic
pressure to drive an output member. These are used
where high speed and large forces are required. The fluid
used in hydraulic actuator is highly incompressible so
that pressure applied can be transmitted instantaneously
to the member attached to it.[3]
• Specification
Stroke 12”
Maximum Capability Pressure 5000 psi
Maximum Working Pressure 3000 psi
Bore Size 4”
Static Pressure Test 4500 psi
Thrust 500 lbs to 50,000 lbs
Temperature Range Standard -40⁰ F to 200⁰ F
29

30. 2. Electric Control Unit : -
• Electronic control unit controls whole active suspension
system. The ECU collects, analyzes and interprets the data
in approximately 10 milliseconds. It sends an urgent
message to the servo atop the right-front coil spring to
"stiffen up." To accomplish this, an engine-driven oil
pump operating at nearly 3000 pounds per square inch
sends additional fluid to the servo, which increases spring
tension, thereby reducing body roll, yaw, and spring
oscillation.[4]
• PID Controller : - PID stands for proportional integral
and derivative. These controllers are designed to eliminate
the need for continuous operator attention. In order to
avoid the small variation of the output at the steady state,
the PID controller is so designed that it reduces the errors
by the derivative nature of the controller.
30

31. 3. Accelerometer : -
• One of the most common inertial sensors is the accelerometer,
a dynamic sensor capable of a vast range of sensing.
• Accelerometers are available that can measure acceleration in
one, two, or three orthogonal axes.[5]
31

32. 32

33. 33

34. • A typical accelerometer has the following basic specifications:
• Number of axes: Accelerometers are available that measure in one, two, or three
dimensions. The most familiar type of accelerometer measures across two axes.
However, three-axis accelerometers are increasingly common and inexpensive.
• Output range (maximum swing): To measure the acceleration of gravity for use as
a tilt sensor, an output range of ±1.5 g is sufficient. For use as an impact sensor,
one of the most common musical applications, ±5 g or more is desired.
• Sensitivity (voltage output per g): An indicator of the amount of change in output
signal for a given change in acceleration. A sensitive accelerometer will be
more precise and probably more accurate.
• Dynamic range: The range between the smallest acceleration detectable by the
accelerometer to the largest before distorting or clipping the output signal.
34

35. • Bandwidth: The bandwidth of a sensor is usually measured in Hertz and indicates the
limit of the near-unity frequency response of the sensor, or how often a reliable
reading can be taken. Humans cannot create body motion much beyond the range of
10-12 Hz. For this reason, a bandwidth of 40-60 Hz is adequate for tilt or human
motion sensing. For vibration measurement or accurate reading of impact forces,
bandwidth should be in the range of hundreds of Hertz.
• Mass: The mass of the accelerometer should be significantly smaller than the mass of
the system to be monitored so that it does not change the characteristic of the object
being tested.
35

36. 4. Steering wheel sensors : -
• The steering position sensor’s basic function is to monitor
the driver’s steering inputs. This includes the angle of the
steering wheel and/or the rate at which the driver is turning
the wheel. The information may be used to vary hydraulic
pressure in a variable-assist power steering system, or by a
stability control system to improve handling, braking and
traction under changing driving conditions.
• Specifications
Response time < 10ms
Rotational speed 2500 0/s (333 rpm)
Accuracy ± 1.50
Turning torque < 80 mN*m
Number of turns ± 3
Acoustic noise < 30 dBA
Operating temperature range -40 to 85 0 C
36

37. 5. Ride height sensor: -
• The ride height sensors give input to smart suspension systems to
adjust the way the suspension reacts to changing road conditions
or load. When traversing along a rough road, it can provide a
smoother ride. On some vehicles, the on-board computer lowers
the vehicle for better aerodynamics when travelling at high speed,
while for four-wheel drive vehicles, the suspension can be raised
to increase the off-road ground clearance.
37

38. • Specifications
Supply Voltage 11 - 30 V DC
Output Voltage 1 - 5 V DC
Max Operating Temperature 0˚C to +55˚C
Storage Temperature -20˚C to +70˚C
Sensor Range 60mm – 260mm
Measurement Rate 500 Hz
Electrical Connection Connector
Environment IP67
Vibration / Shock 10Hz – 1 kHz, 15g
Weight (without cable or connector) 100g
Laser 1mW, 670 nm, Pulsed Radiation
38

39. 6. Wheel speed sensors : -
• Based on their mode of functioning, wheel speed sensors are classified
into active and passive sensors. If a sensor becomes "active" only when
a power supply is connected to it and if it then generates an output
signal, it is called active.
• If a sensor works without an additional power supply, then it is called
passive
• Gyroscope is an example of wheel speed sensor i.e. measures angular
velocity
39

40. • A gyroscope sensor has the following basic specifications:
• Measurement range: This parameter specifies the maximum angular speed with which
the sensor can measure, and is typically in degrees per second (˚/sec).
• Number of sensing axes: Gyroscopes are available that measure angular rotation in one,
two, or three axes. Multi-axis sensing gyros have multiple single-axis gyros oriented
orthogonal to one another. Vibrating structure gyroscopes are usually single-axis (yaw)
gyros or dual-axis gyros, and rotary and optical gyroscope systems typically measure
rotation in three axes.
• Working temperature range: Most electronics only work in some range of temperatures.
Operating temperatures for gyroscopes are quite large; their operating temperatures
range from roughly -40˚C to anywhere between 70 and 200˚C and tend to be quite linear
with temperature.
40

41. • Shock survivability: In systems where both linear acceleration and angular rotation rate are
measured, it is important to know how much force the gyroscope can withstand before
failing. Fortunately gyroscopes are very robust, and can withstand a very large shock (over
a very short duration) without breaking. This is typically measured in g’s (1g = earth’s
acceleration due to gravity), and occasionally the time with which the maximum g-force can
be applied before the unit fails is also given.
• Bandwidth: The bandwidth of a gyroscope typically measures how many measurements can
be made per second. Thus the gyroscope bandwidth is usually quoted in Hz.
• Bias: The bias, or bias error, of a rate gyro is the signal output from the gyro when it is NOT
experiencing any rotation. Even the most perfect gyros in the world have error sources and
bias is one of these errors. Bias can be expressed as a voltage or a percentage of full scale
output, but essentially it represents a rotational velocity (in degrees per second).
41

42. • Bias Drift: This refers specifically to the variation of the bias over time, assuming all other
factors remain constant. Basically this is a warm-up effect, caused by the self heating of the
gyro and its associated mechanical and electrical components. This effect would be
expected to be more prevalent over the first few seconds after switch-on and to be almost
non-existent after (say) five minutes.
• Bias Instability: Bias Instability is a fundamental measure of the 'goodness' of a gyro.
42

43. 43
Simulation And Results For Active Suspension System
Mathematical Model Of Active Suspension System

44. 44

45. Simulink Model Of Active Suspension System
45

46. Subsystem
46

47. 47
Car body displacement for 10 cm step input(Active)

48. Comparison – Passive & Active Suspension System
48

49. Conclusion
• The methodology was developed to design an active suspension for a passenger
car, which improves performance of the system compared to passive suspension
system. Mathematical modeling has been performed using a two degree-of-
freedom model of the quarter car model for passive and active suspension system
considering only bounce motion to evaluate the performance of suspension with
respect to various contradicting design goals. PID controller design approach has
been examined for the active system. Suspension travel in active case has been
found reduced. By including an active element in the suspension, it is possible to
reach a better compromise than is possible using purely passive elements. The
potential for improved ride comfort and better road handling using PID controller
design is examined. Model for linear quarter car suspensions systems has been
formulated and derived only one type of controller is used to test the systems
performance which is PID.
49

50. WORK SCHEDULE WITH FUTURE PLAN
6-Aug 13-Aug 20-Aug 27-Aug 3-Sep 10-Sep 17-Sep
Literature Review
Types Of Suspension System
Finalysing of type of suspension system
Finding technical data/parameter related to passive suspension
Passive suspension system modelling
Simulation and analysis of passive suspension system with results
Finding out componets related to active suspension
50

51. WORK SCHEDULE
51

52. References
1. K. El Majdoub, F. Giri, F.Z. Chaoui, (2013). “Back Stepping Adaptive Control Of
Quarter-vehicle Semi-active Suspension With Dahl MR Damper Model”. IFAC
Proceedings Volumes, Volume 46, Issue 11, 2013, Pages 558-563.
2. Dr. Pushpendra Sharma, Prof. S.C.Jain, Dhara Vadodaria, “Design And
Calculation Of Mcpherson Suspension System And Modified Suspension System And
Its Comparison”, International Journal of Advanced Technology in Engineering and
Science, ISSN(online): 2348 – 7550, Volume No. 02, Issue No. 08, Pg – 488 – 493.
3. http://nptel.ac.in/courses/108105063/pdf/L26(SM)%20(IA&C)%20((EE)NPTEL).pdf
4. http://www.edmunds.com/car-technology/suspension-iii-active-suspension-
systems.html
5. http://sensorwiki.org/doku.php/sensors/accelerometer.
52