Modified Electromagnetic Actuator for Active Suspension System

International Journal of Engineering and Management Research e-ISSN: 2250-0758 | p-ISSN: 2394-6962
Volume-11, Issue-4 (August 2021)
www.ijemr.net https://doi.org/10.31033/ijemr.11.4.23
188 This Work is under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
Modified Electromagnetic Actuator for Active Suspension System
Prajwal V R1
, Chandrashekar Murthy B N2
and Yashwanth S D3
1
PG Scholar, Department of Electronics and Communication, SJCE, JSS STU, Mysuru 570006, INDIA
2
Lecturer, Department of Electronics and Communication, SJCE, JSS STU, Mysuru 570006, INDIA
3
Lecturer, Department of Electronics and Communication, SJCE, JSS STU, Mysuru 570006, INDIA
2
Corresponding Author: chandrashekar@sjce.ac.in
ABSTRACT
Active suspension is a type of suspension systems
which can vary its damping value in order to adjust the
spring firmness in accordance with the road conditions. Real
Active Suspension incorporates an external actuator which
helps in raising or lowering of vehicle chassis independently
at each wheel. Generally, the actuators that are used for
active suspension are Hydropneumatic, Electro-hydraulic or
Electromagnetic actuators. A new concept of two-way
electromagnetic actuation with the help of magnetic
damping is proposed in this paper, which can extend its arm
on both sides to facilitate active suspension mechanism in
both humps and potholes. This increases the ride quality
while maneuvering not only in humps, but also in dumps. It
also describes about the comparison of spring materials,
sophisticated design, construction and working principle of
newly proposed actuator. Catia V5 software has been used
to design and simulate the actuator model, different spring
materials are analyzed and their shear stress and deflections
are compared.
Keywords-- Electromagnetic Actuator, Magnetic
Damping, Double Wishbone Suspension
I. INTRODUCTION
Conventional Suspension system cannot fully
eliminate the shocks and are inefficient in terms of
controlling the vibration occurred due to uneven road
surfaces which makes the ride uncomfortable. In order to
increase the ride quality, the conventional passive
suspension mechanism has been advanced to semi-active
and active suspension systems [1-3] which enhances ride
quality and vehicle handling capability during cornering,
accelerating and braking. Semi-active suspension offers
limited number of damping ratios which can be switched
between riding modes such as comfort, sport, power etc. it
does not contain an external actuator and hence cannot add
energy into the system. On the other hand, Active
Suspension system offers variable damping ratio with
larger time response, it also accommodates an external
actuator which increases the ride comfort by raising or
lowering of vehicle chassis independently at each wheel.
Actuators plays a vital role in Active Suspension
system as it exerts counter force to eliminate the body roll
and pitch variation, this makes the vehicle stable and
improves traction. Majority of the cars from Mercedes
Benz and Citroen which are equipped with active
suspension uses Hydropneumatic actuator [4] whereas, the
cars having Electromagnetic actuator is not yet
commercially available. In 2018 for the very first time,
Bose has demonstrated active suspension mechanism
using Electromagnetic actuator. [5-7] A two-way
actuation mechanism, has been proposed, in order to
facilitate the active suspension in both humps and dumps.
The actuator works on the principle of electromagnetism
where, a calculated amount of current is passed through
the coil, which generates magnetic flux around the
electromagnetic coil. This magnetic flux can attract or
repel a permanent magnet based on the polarity of the
current supplied through the coil. This attraction or
repulsion constitutes for magnetic damping which makes
the actuator arm to expand or compress, resulting in uplift
movement or downward movement of vehicle wheels.
II. METHODOLOGY
The proposed electromagnetic actuator consists
of a moving a cylinder called mover, which are attached
with permanent magnets and two set of copper coils
placed at both end of the cylinder as shown in figure 1.
Mechanical springs are present to absorb the vibrations,
when a vehicle navigates over uneven road surfaces.
Figure1: Electromagnetic actuator
The electromagnetic actuator has been coupled
with modified double wishbone suspension mechanism in
order to accurately move the vehicle’s wheel up and
down. Double wishbone suspension consists of lower arm
and upper arm, the mechanical spring has been replaced
by electromagnetic actuator. The suspension mechanism
has been designed and simulated using Catia V5 software
as shown in figure 2. It is designed with the following
parameters as shown in table 1. The design induces 00
for

both caster and camber have kingpin inclination of 470
. [8-
9]
Figure 2: Suspension mechanism
Table 1: Suspension design parameters
Specifications Values
Arm length 65 mm
Spring stiffness 24.5 N/mm
Spring wire Diameter 5 mm
Spring length 36 mm
No of turns 10
Nominal actuator length 90 mm
Max stroke length 105 mm
Min stroke length 70 mm
Max angle of elevation +250
Max angle of depression -230
Max wheel lift ±26 mm
The actuator has been designed for two-way
actuation so that, the actuator arm can both expand and
compress depending upon the polarity of current supplied
through the coil. The cross section of proposed actuator is
shown in figure 3 and working of actuator is demonstrated
with help of flow chart in in the figure 4.
Figure 3: Cross section of actuator
When the vehicle wheels encounter an elevation
in road surface. Radar sensor gathers information and
gives input to processor. Processor calculates the average
height, with which the actuator needs to compress, so that
vehicle wheels can be lifted by keeping the vehicle chassis
at constant level. Both the copper coils are energized by
supply of current with negative polarity, to induce south
pole so that, electromagnet and permanent magnet present
in top position attracts each other. At the same time,
electromagnet and permanent magnet present in bottom
position repels each other. This entire combination
constitutes for magnetic damping and pushes the mover
inside the upper coil, resulting in uplift movement of the
actuator.
Figure 4: Flow chart
Similarly, when the vehicle wheels encounter
dumps or potholes which are below the road surface, both
the coils are energized by supply of current with positive
polarity, to induce north pole so that, the repulsion takes
place in top portion and attraction takes place in bottom
portion of the actuator. This combination pushes the
mover inside the below coil, resulting in downward
movement of actuator.
Electromagnet [EM] is constructed by wounding
a copper coil of length ‘L’ on a solenoid with ‘N’ turns,
current ‘I’ is allowed to flow through solenoid as shown in
figure5. From Amphere’s law, the magnetic flux (B)
produced by solenoid is given by,

Figure5: Solenoid (Electromagnetic coil)
I N / L equation (1)
= permeability of free space = 4π x 10-7 N/A2
I = Current supplied
N = Number of turns
L = Length of wire
The magnetic field produced by permanent
magnet [PM] is constant and is directly proportional to its
dipole moment ‘m’. The force of attraction or repulsion
(F) between these permanent magnet and electromagnet is
given by,
F = m.B*cosθequation (2)
m = magnetic dipole moment
B = magnetic flux created by electromagnet
Cos θ = 1, since θ = 00
because of same direction
From the above equations (1) and (2), the current
supplied through the coil is directly proportional to change
in force of attraction or repulsion PM, which makes mover
present inside the cylinder to move up or down depending
up on the polarity of the current. The force of attraction
and repulsion between PM and EM can be controlled by
varying the current through the coil, which makes the
mover stable at a certain position. Thus, actuator can
achieve variable stroke length enabling active suspension
in both humps and dumps up to 26 mm.
This technique moves only the vehicle wheels
and helps in maintaining the vehicle chassis at constant
level which provides maximum comfort level to
passengers. The actuator also helps in eliminating the
body roll during cornering, by stabilizing the chassis at
constant level. A positive potential difference of 5V
consisting of 40mA current is supplied, in order to fully
energize the coil to have maximum wheel lift. Wishbone
suspension mechanism has been designed where its arms
can make a rotation from +250
to -230
. The actuators can
vertically move up and down the wheel by ±26 mm.
A. Spring Material Comparison
Automobile suspension springs can be
manufactured using different materials, commonly used
materials for forming a spring are chromium vanadium,
chromium silicon and stainless steel of 17-7 PH grade.
These materials are compared with their minimum tensile
strength, young’s modulus, modulus of rigidity, density
and maximum operating temperature as shown in table 2.
Spring constant depends up on young’s modulus and
Poisson’s ratio which can offer variable damping ratio to
facilitate active suspension. All three materials are
compared and it is seen that chromium vanadium material
is best suited for automobile suspension for taking heavy
loads.
Table 2: Comparison of Spring material
property Chromium
Vanadium
Chrome
Silicon
Stainless
steel
Young’s
Modulus 30 MPa 30 MPa 29.5 MPa
MinTensile
Strength
1310 - 2068
MPa
1620 - 2068
MPa
2068 - 2309
MPa
Density 7860 kg/m3
7861 Kg/m3
7800 Kg/m3
Modulus
Torsion (G)
11.5 * 106
psi
11.5 * 106
psi
11 * 106
psi
Max
operating
Temperature
2180
C 2460
C 3400
C
III. RESULTS & DISCUSSIONS
The actuator lifts up or lifts down the wheel
depending upon the control signal given by ECU. Results
are discussed with different scenarios involved.
A. Actuator Analysis
Depending upon the attraction or repulsion of
EM’s and PM’s, the vehicle wheel moves up or down. At
Maximum stroke length, the vehicle wheel can be lifted
down up to 26 mm below road surface and at minimum
stroke length, vehicle wheel can be lifted up to 26 mm
above road surface. The actions of actuator are discussed
below in following cases and is represented in figure 6.
Figure 6: Voltage vs Actuator length
B. Vehicle Maneuvering over Flat Road
All the vehicle wheels are in contact with road
surface. there is no movement involved in actuator. The
mechanism rests at constant position.
C. Vehicle Encountering Humps
When vehicle encounters humps, there is uplift
movement of vehicle wheel keeping chassis at constant
level. Suspension mechanism has been designed to raise
the wheel by maximum height of 26mm by raising 250
with respect to chassis level. Figure 7, represents
-20
-10
0
10
20
-5 -2.5 0 2.5 5
ACTUATOR
LENGTH
(MM)
VOLTAGE (V)
Voltage vs Actuator length

variation in suspension mechanism when vehicle
encounters humps in different scenarios.
Case 1: Vehicle over humps, where hump height ‘h’ ≥
20mm
The actuator fully compresses in order to lift the
wheels up. This can be achieved by supplying maximum
voltage of 5 V with negative polarity across both coil 1
and coil 2, which makes both the coil as south pole. This
attracts PM in top portion and repels PM in bottom
portion resulting in compression of actuator. Suspension
mechanism raises its arm up to 250
enabling wheel lift up
to 26 mm.
Figure 7a: Suspension in humps (case 1)
Case 2: Vehicle over humps, where 0 ≤ h ≤ 20mm
The actuator partially compresses and also
partially lifts up the wheel above road surface. This is
achieved by supplying -4 V across the coil 1 and +1 V
across coil 2. This makes coil 1 as south pole and coil 2
as north pole. The force of attraction is greater near coil 1
and lower near coil 2. The mover attains levitating state
and remains constant near coil 1, resulting in partial
compression of actuator. Suspension mechanism raises its
arm up to 200 enabling maximum wheel lift of 20 mm.
Figure 7b: Suspension in humps (case 2)
D. Vehicle Encountering Dumps
Suspension has been designed to lower the
wheel by maximum height of -26mm, which is below
ground level. Active suspension cannot be fully
functional in case of dumps because of its restriction in
lowering of wheels is limited by design parameters, but
there are plenty of potholes with different depths
variation. Figure 8 represents variation in suspension
mechanism while vehicle encountering dumps in different
scenarios
Case 3: Vehicle over dumps, where dump depth ‘d’ ≥
20mm
The actuator fully expands in order to lift the
wheels down. This can be achieved by supplying
maximum voltage of +5 V across both coil 1 and coil 2,
which makes both the coil as north pole. This repels PM
in top portion and attracts PM in bottom portion resulting
in expansion of actuator and thus moving the vehicle
wheels down. Suspension mechanism lowers its arm up
to 230
enabling wheel lift down up to 26 mm.
Figure 8a:Suspension in dumps (case 3)
Case 4: Vehicle over dumps, where 0 ≤ d ≤ 20mm
The actuator partially expands and also partially
lifts down the wheel below road surface. This is achieved
by supplying -1 V across the coil 1 and +4 V across coil
2. This makes coil 1 as south pole and coil 2 as north
pole. The force of attraction is greater near coil 2 and
lower near coil 1. The mover attains levitating state and
remains constant near coil 2, resulting in partial
expansion of actuator. the arms are lowered up to 200
which will lower the wheel up to 20 mm.
Figure 8b:Suspension in dumps(case 4)
A. Spring Deflection
The Actuator spring is analyzed using Ansys tool, where
different loads are applied on the spring and its
corresponding shear stress is noted.

Figure 9a: Load vs shear stress
Chromium vanadium and hard carbon spring
steel are analyzed by creating mesh model. [10] Mesh
model contains number of nodes and elements which
helps to analyze applied load under specific boundary
conditions. Circular cross section spring are analyzed at
different loads of 55 N, 65 N, 75 N, 85 N and 95 N.
Figure 9a represents variation of shear stress and load.
Figure 9b represents variation of deflection and load.
Figure 9b: Load vs deflection
IV. CONCLUSIONS
Electromagnetic actuator has various advantages
over hydraulic actuators because of its characteristics.
Both springs and dampers are combined together in
electromagnetic actuator which impacts weight and
compactness in the vehicle. Two-way actuation is most
efficient in electromagnetic actuator as it can be easily
controlled by varying the current through the coil. The
mechanism has been designed and simulated using Catia
V5 and Lotus software’s ensuring proper working of
active suspension using electromagnetic actuator in both
humps and dumps. Chromium vanadium steel, chrome
silicon and stainless-steel spring materials are compared
with their respective physical properties. It is found that
chromium vanadium steel is best among all three because
of its properties.
A. Future Scope
The firmware of this project can be
upgraded to facilitate raising or lowering of vehicle
chassis. Lowering of vehicle chassis has many advantages
such as improved fuel economy, increase in
aerodynamics and better comfort to passengers for easy
boarding and de-boarding. Also, raising of vehicle chassis
helps in increasing ground clearance. The suspension
mechanism can be enhanced with high quality design to
achieve greater stability during cornering, increasing of
wheel lifting capacity and offering variable ride modes
with different damping coefficients.
REFERENCES
[1] Bart L. J. Gysen, Johannes J. H. Paulides, Jeroen L.
G. Janssen, & Elena A. Lomonova. (2010). Active
electromagnetic suspension system for improved vehicle
dynamics. IEEE Transactions on Vehicular Technology.
[2] A Gupta, J A Jendrzejczyk, T M Mulcahy, & J R
Hull. (2007). Design of electromagnetic shock absorbers.
Springer.
[3] Babak Ebrahimi, Hamidreza Bolandhemmat, Mir
Behrad Khamesee, & Farid Golnaraghi. (2014). A hybrid
electromagnetic shock absorber for active vehicle
suspension systems. Vehicle System Dynamics:
International Journal of Vehicle Mechanics and Mobility.
[4] B Gao, J Darling, D G Tilley, R A Williams, A Bean,
& J Donahue. (2006). Control of a hydropneumatic active
suspension based on a non-linear quarter-car model.
Proc. IMechE, 220(I: J). Systems and Control
Engineering.
[5] Mohammed Al-Ashmori & Xu Wang. (2020). A
systematic literature review of various control techniques
for active seat suspension systems. Applied Sciences.
[6] Sharad S Jadhav, Dr. S.S.Kulkarni, & Prof. Amod
.P.Shrotri. (2016). Suspension system with broad
classification and various models: A review.
International Journal of Advanced Technology in
Engineering and Science.
[7] Hazril M. Isa, Wan Nor Liza Mahadi, & Rahizar
Ramli. (2011). A review on electromagnetic suspension
systems for passenger vehicle. International Conference
on Electrical, Control and Computer Engineering.
[8] M.S. Swami, Omkar Satpute, Vrinali Jadhav, Chirag
Mohite, & Rushikesh Kumbhar. (2019). Design &
manufacturing of double wishbone suspension and wheel
assembly for formula style vehicle. International
Research Journal of Engineering and Technology.
[9] N.Lavanya, P.Sampath Rao, & M.Pramod Reddy.
(2014). Design and analysis of a suspension coil spring
300
350
400
450
500
550
600
650
700
55 65 75 85 95
Shear
Stress
in
MPa
Load in N
Variation of Shear stress
Chromium vanadium steel Hard Carbon steel
80
100
120
140
160
180
55 65 75 85 95
Shear
Stress
in
MPa
Load in N
Variation of Deflection
Chromium vanadium steel Hard Carbon steel

for automotive vehicle. International Journal of
Engineering Research and Applications.
[10] Harshal Rajurakar & M. C. Swami. (2016). Analysis
of helical compression spring for two wheeler automotive
rear suspension. IOSR Journal of Mechanical and Civil
Engineering, 13(2).
[11] Ankita R. Bhise, Rutuja G. Desai, Mr. R. N.
Yerrawar, Dr. A.C. Mitra, & Dr. R. R. Arakerimath.
(2016). Comparison between passive and semi-active
suspension system using matlab/simulink. IOSR Journal
of Mechanical and Civil Engineering.
[12] Yu-Jeong Shin, Won-Hee You, Hyun-Moo Hur, &
Joon-Hyuk Park. (2012). Semi-active control to reduce
carbody vibration of railway vehicle by using scaled
roller rig. Journal of Mechanical Science and
Technology, Springer.
[13] Youngjoo Chn, Byung Suk Song, & Kyongsu Yi.
(1998). A road-adaptive control law for semi-active
suspensions. KSME International Journal.
[14] Aizuddin Fahmi, Mohd Riduan,
NoreffendyTamaldin, AjatSudrajat, & Fauzi Ahmad.
(2018). Review on active suspension system. ICES.
[15] Sara Sharifi, Sedeh, Reza, Sharifi Sedeh, & Keivan
Navi. (2006). Reducing harmful effects of road
excitations on human health by designing car active
suspension systems. ResearchGate.
[16] Na Jiao, Jianjuan Guo, & Shulin Liu. (2017). Hydro-
pneumatic suspension system hybrid reliability modeling
considering the temperature influence. IEEE Access.
[17] Sarvadnya Ajinkya Thakare, Prasad C Antapurkar,
Divyaj S Shah, P R Dhamangaonkar, & S N Sapali.
(2015). Design and analysis of modified front double
wishbone suspension for a three wheel hybrid vehicle. In:
Proceedings of the World Congress on Engineering.

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