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NAME: Haitham Abdelbary Mohamed
Student id:TP057735
Lecturer name: Hazwani Mohd Rosli
Module Name: Generation Transmission and distribution of electric power.ASIA PACIFIC
UNIVERSITY TECHNOLOGY & INNOVATION EE036-4-2 GENERATION,
TRANSMISSION AND DISTRIBUTION OF ELECTRICAL POWER GUIDED LAB
MANUAL TRANSMISSION LINE PERFORMANCE
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Table of Contents
List of Figures………………………………………………………………………….…………………4
Introduction...............................................................................................................................................5
Individual…………………………………………………………………………………...…………….10
Controller chosen:...............................................................................................................................10
Actuator chosen:..................................................................................................................................14
Results and Analysis:...........................................................................................................................15
Discussion……………………………………………………………………………………………………………………………………….15
Further Improvement:........................................................................................................................20
Conclusion:..........................................................................................................................................20
References……………………………………………………………………………………………………………………………………….22
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List of Figures
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Introduction
Vehicle suspension system is an essential system which consists of several components which
are the tyres, springs, shock absorbers, and connections. This combination of components
enables a comfortable usage of the vehicle and plays a vital role in handling of the vehicle and
safety of the occupants. The suspension systems work on regulation of all the forces which are
external such as uneven road surface which causes vibration in the vehicle and might be
disturbing. (Jiregna & Sirata, 2020).
Suspension system mechanism comprises of springs, dampers, and actuators. Suspension of a
vehicle works by isolating the body of the vehicle from the wheels physically, this mechanism
has the springs converting kinetic energy to potential energy and vice versa while the dampers
works on the dissipation of the energy and slowing down the vibrations. Shock absorbers act as
actuators which are commonly hydraulic pumps in vehicles assist in the regulation of the impact
and rebound of the suspension springs, while maintaining continuous contact between the tyres
and the road surface which in return optimises the control and braking of the vehicle. .
(Mongi et al., n.d.)
The primary function of the vehicle suspension system is to mitigate the vertical acceleration that
is transferred to the vehicle body, ultimately providing comfort to the occupants or cargo within
the vehicle. Consequently, the suspension system serves many key functions. Firstly, it is
designed to prevent the transmission of road shocks to the various components of the vehicle.
Additionally, it plays a crucial role in safeguarding the occupants of the vehicle by minimising
the impact of road shocks. Lastly, the suspension system is responsible for maintaining the
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stability of the vehicle during pitching or rolling movements that occur while the vehicle is in
motion. (Sammier et al., 2003)
Research continues as the growing requirements of higher standards of stability and rapid
advancements including hybridization of automotive vehicles. This leads to an outcall and
adoption of new suspension principles or systems which can improve or enhance stability,
control, comfort, and most importantly safety of the occupants and the road users.
In order to make adjustments to the suspension system, a comprehensive comprehension of both
the intricate workings of car suspension networks and the principles governing vehicle dynamics
is needed. Maintaining continuous contact between the wheel and the road surface is of utmost
importance for ensuring the safety of vehicle operation. This is due to the fact that the entire
weight of the car is transmitted through the contact areas of the tyres (Jiregna & Sirata, 2020).
Figure 1 Car Suspension system
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Given that the only points of contact between cars and the ground are the wheels, it is imperative
to incorporate a suspension system, as depicted in Figure 1, into each wheel of an automobile.
The operational principle of this system involves the vertical movement of the wheels when
encountering a speed breaker. This movement is effectively muted by the dampers in conjunction
with the springs, hence enhancing the durability of the springs and improving the overall comfort
experienced by the vehicle occupants. The energy resulting from the compression of the spring is
subsequently passed to the actuator. The specific type of actuator employed determines its
response in counteracting this force, thereby contributing to the overall stability of the vehicle.
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Individual:
Controller chosen:
A variable damping stiffness coefficient damper is used in the semi-active suspension system,
which is powered by an external source of energy and controlled by an integrated controller that
has a number of sensors. The amount of damping needed for the particular road. The controller
chooses a profile and then modifies the damper to produce the desired dampening. A comparable
passive suspension system and a proportional integral derivative (PID) control system were
created, tested, and compared for various forms of road disturbances. A feedback mechanism in
the semi-active suspension structure regulates the damper's damping coefficient. This feedback is
utilized to produce a PID controller's reaction, which in turn modifies the damper's damping
stiffness. The system's other elements are unchanged. A semi-active suspension system's block
diagram is seen in Figure.
Fig. Block diagram of semi-active vehicle suspension system
Controller Architecture:
To execute the control strategy, a proportional-integral-derivative (PID) controller was selected.
The PID controller offers a simple yet effective method for controlling the damping force based
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on velocity feedback. It may be tweaked to meet desired stability and comfort levels, and
because it's so straightforward, real-time implementation is made possible.
Optimization and Tuning:
Simulated and empirical testing were used to fine-tune the PID controller's settings. A high-
fidelity vehicle dynamics model was used in simulation experiments to evaluate the controller's
performance in a variety of driving situations. The goal of the tuning procedure was to find a
balance between limiting bodily motion and avoiding exerting too much control.
A well-known and often used control algorithm is we used in this project PID controller
(Proportional-Integral-Derivative). Based on the error (difference from the desired state), its
integral (cumulative error), and its derivative (pace of change of error), it modifies the control
input (damping force in this example). A well set PID controller may increase the vehicle's
responsiveness to shifting road conditions while still ensuring stability. Adjusting control
parameters to achieve optimal values that provide the expected response in an automation system
is known as loop tuning.
Response of P controller:
Figure step response of P controller
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Rise time, T r = 1.6 s
Peak time = 0.43 m T p= 1.95 s
Settling time, T s = 2.82s
C
overshoot%= ×100 %, where C= 0.032, D=0.3
D
= 9%
Response of PI controller:
Figure PI controller’s step response
Rise time, T r = 1.53 s
Peak time = 0.465 m T p= 1.95 s
Settling time, T s = 4.05s
C
overshoot%= ×100 %, where C= 0.165, D=0.3
D
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= 55%
Response of PID controller:
Figure PID controller’s step response
Rise time, T r = 1.6 s
Peak time = 0.356 m T p= 1.92 s
Settling time, T s = 4.94s
C
overshoot%= ×100 %, where C= 0.056, D=0.3
D
= 18.6%
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Actuator chosen:
The actuator works by adjusting the flow of hydraulic fluid or air in the suspension system.
When the vehicle encounters a bump or rough road, the actuator will adjust the flow of fluid or
air to cushion the impact and reduce the amount of shock absorbed by the vehicle. This helps to
improve ride comfort and stability. Using the actuator, you can adjust the damping characteristics
of the suspension to enhance ride comfort and vehicle stability. Actuators adjust suspension
damping characteristics to enhance vehicle stability and ride comfort. The actuator used in this
project is MR actuator. MR stands for Magneto-Rheological damper, The MR fluid is composed
of small particles suspended in a liquid carrier. When a magnetic field is applied to the fluid, the
particles align and the viscosity of the fluid increases. This allows the damping force to be
adjusted in real-time, making it ideal for semi-active suspension systems that need to respond
quickly to changes in the road surface. The ability to tune the damping force also makes MR
dampers an attractive option, as they provide a balance between the passive and fully active
systems. Magnetorheological fluid, whose viscosity alters to respond to an imposed magnetic
field, is used in MR dampers. As a result, the damping force may be adjusted in real time and
under control. Due to its short reaction time and adjustable damping qualities, MR dampers are
frequently utilized in semi-active suspension systems. They offer a compromise between totally
active and passive systems.
x s (s ) ms
T ( s )= =
x z (s) ms∗Ks+ cs∗( ms+ μ )∗s 2
Where,
ms = sprung mass
μ = un-sprung mass
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Ks = suspension stiffness
cs = suspension damping ratio
s = Laplace variable (complex frequency)
Results and Analysis:
Figure Matlab model of semi-active vehicle control
This system is designed to ensure that the vehicle remains stable and operates at optimal levels of
performance, while also reducing the amount of vibration and noise that the vehicle produces.
Discussion:
The PID controller helps to ensure that the force applied by the actuator is kept within a certain
range, while the acceleration variable is used to monitor the effect of the force applied on the
vibration of the vehicle. By monitoring the acceleration of a vehicle, companies can assess the
performance of the car as it relates to fuel efficiency, safety, and environmental impact. This data
can then be used to inform decisions about design and maintenance that can improve the overall
performance of the car. The semi-active vehicle control system's separate parts are depicted in
the image above. The reference force and disturbance applied to the individual resemble the
component of the group. To create the displacement, a force is applied to the semi-active vehicle
suspension control plant with the aid of an MR actuator under the direction of a PID controller.
The displacement reveals the vehicle's vibration. This control system's goal is to govern the
semi-active vehicle control system with the use of an actuator. To reduce vehicle vibration
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throughout the procedure, a PID controller is employed to manage the force delivered. Having a
scope to see how the acceleration variable changes over time is another way to monetize it. By
monitoring the acceleration of a vehicle, companies can assess the performance of the car as it
relates to fuel efficiency, safety, and environmental impact. This data can then be used to inform
decisions about design and maintenance that can improve the overall performance of the car.
Figure Matlab model of semi-active vehicle suspension model with actuator (MR damper)
A comprehensive examination of the passive suspension system was meticulously conducted
through the development of a MATLAB model. The simulation harnessed the vehicle suspension
parameters detailed in this section. The resulting simulation output, illustrated in Figure given
below pertains to a step input of 0.1 meters in magnitude. The graph visually traces the evolution
of body displacement across a simulation time span of 10 seconds.
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Figure The displacement of the vehicle body before and after a step input in a passive suspension
The graphical representation offers valuable insights: the utmost displacement achieved is 40
millimeters (equivalent to 0.04 meters). Additionally, a secondary peak is evident, measuring 5
millimeters. Notably, the system's settling time is approximately 2 seconds. This analysis
empowers us with a quantitative understanding of the passive suspension system's behavior. By
scrutinizing the simulation outcomes, we can decipher critical performance aspects such as peak
displacement and the time required for the system to stabilize following a perturbation. This
information forms a foundational baseline against which potential enhancements such as the
implementation of a semi-active control approach can be evaluated.
In the context of a vehicle equipped with a passive suspension system traversing a speed breaker,
a pertinent investigation unfolds. The impact of the speed breaker-induced road disturbance is
ingeniously replicated through a pulse input within the MATLAB suspension model. This
emulation manifests the transient effects experienced when encountering a speed breaker on an
actual road. To align the simulation closely with the road reality, the pulse input is tailored with a
step magnitude of 0.1 meters and a duration of 25 milliseconds. The determination of this pulse
duration is a thoughtful process. By accounting for a vehicle speed of 10 kilometers per hour and
the width of the speed breaker (measured at 0.4 meters), a meticulous estimation ensues. The
resultant value of 25 milliseconds encapsulates the time span required for a vehicle moving at the
specified speed to traverse the width of the speed breaker.
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Figure an impulse input results in a vehicle body displacement over time
The graphical representation depicted in Figure given below illustrates the dynamic evolution of
body displacement over a 10-second simulation duration. This graph is a visual encapsulation of
how the vehicle's body position evolves in response to changing conditions over time. From a
careful observation of the graph, several noteworthy trends emerge. This peak represents the
farthest point the body deviates from its equilibrium position due to external forces or road
disturbances. The settling time, the duration it takes for the body to regain stability after being
perturbed, is calculated to be approximately 1 second.
Figure Semi-active suspension with MR damping displacement at a step input
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Additionally, an intriguing observation is the substantial reduction in the magnitude of
oscillations in the vehicle's displacement. The graph indicates that the amplitude of the
oscillations has been markedly curtailed. This effect is particularly significant as it signifies the
capability of the system to minimize the disruptive motion that typically occurs in response to
road disturbances. The sustained low-amplitude fluctuations visible on the vertical axis
throughout the observation period underscore the system's effectiveness in dampening
oscillations and ensuring a smoother response to road irregularities. This analysis illuminates the
system's capacity to mitigate unwanted vertical movement, showcasing the integral role of
Magneto-Rheological (MR) damping in enhancing vehicle stability and passenger comfort. By
diligently attenuating the extent and duration of oscillations, the MR damping mechanism plays a
pivotal role in achieving a smoother and more controlled ride experience over diverse road
conditions.
The figure given below exemplifies the dynamic behavior of a MATLAB model representing a
semi-active suspension system when subjected to a pulse input, simulating the vehicle's traversal
over a road bump, akin to a common speed breaker. The design of the pulse input is thoughtfully
tailored to mimic a real-world scenario, with a step magnitude set at 0.1 meters and a pulse
duration spanning 25 milliseconds.
Figure Semi-active suspension with MR damper displacement with time for an impulse input
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The graph vividly portrays the vehicle's instantaneous response as it encounters the simulated
speed breaker. In this moment, the vehicle's body experiences a sudden, pronounced jolt,
resulting in a vertical displacement of 0.04 meters. Subsequent observations reveal a recurring
pattern of diminished jerks, each possessing an amplitude below 0.015 meters. This pattern
persists for approximately 0.3 seconds before the vehicle's response attains a steady state around
the 0.9-second mark. Evidently, this sequence of events implies that the semi-active suspension
system, as depicted in this specific simulation, does not demonstrate a notably superior response
compared to a passive suspension system.
Further Improvement:
Model predictive control, adapted control, & neural network-based methods all have the
potential to provide improved flexibility and responsiveness to a variety of driving
circumstances. Future research may concentrate on multi-objective optimization, taking ride
comfort, stability, energy efficiency, and road handling into account concurrently. This would
aid in determining the best trade-offs between these conflicting goals, resulting in a system that
is more comprehensive and adaptable. The system's performance may be enhanced even further
by integrating real-time road condition sensor technology. The control system might adjust
damping settings much more successfully to guarantee optimal vehicle behavior by precisely
identifying road surface characteristics.
For practical applications, researching energy consumption optimization is crucial. Sustainability
would be improved by putting in place energy recovery devices or adaptive control techniques
that reduce energy use without sacrificing performance. The semi-active system should be
integrated into a genuine vehicle platform in the future, and thorough testing should be done
under a variety of traffic situations. This would enable a more precise evaluation of the system's
effectiveness in real-world situations.
Conclusion:
In this project, we created and put into practice a proportional-integral-derivative (PID)
controller with a magneto-rheological (MR) damper as the actuator for a semi-active vehicle
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control system. By dynamically modifying damping forces in response to shifting road
conditions and control inputs, the system seeks to balance ride comfort with vehicle stability.
The semi-active automobile control system has the potential to considerably improve handling
and ride quality, according to testing and implementation results. In comparison to passive
suspension systems, we found that active suspension systems reduced body movements,
improved road holding, and improved the overall driving experience. An ideal trade-off
involving ride convenience and steering effort was achieved by the tuning of the PID controller.
Although the outcomes of our implementation have been encouraging, there are still
opportunities for improvement. Every component of the quarter-car model is taken into account
in this project, including the tyres stiffness and damping as well as the controller system and the
intricate MR fluid model. The suspension piston's damping force and velocity are used to create
the hysteresis curve. The MR fluid's nonlinear hysteric behavior is studied using the model.
Because the control is effective when all the fluid characteristics are taken into account, the
vehicle's stability is increased. It also showed random and periodic stimulation, and after a short
amount of time, the sprung mass stabilized, improving the stability of the semi-active system.
The outcomes of our project unveil the impressive efficacy of the PID controller crafted for the
semi-active system. This controller exhibits remarkable enhancements in mitigating body and
suspension oscillations, as well as in accelerating settling times. As a result, our conclusion
underscores that the integration of an active damping element can significantly amplify both ride
comfort and vehicle stability, particularly under adverse road conditions.
For prospective investigations in this domain, we recommend a focus on two key avenues.
Firstly, delving into the development of a self-tuning PID controller or exploring alternative
control methodologies holds promise for refining the system's adaptive capabilities. This could
potentially lead to even more optimized performance across varying driving scenarios. Secondly,
the achievements demonstrated through simulations in this study warrant empirical validation
through practical experiments. By corroborating simulation findings with real-world testing, the
robustness and applicability of our findings can be further solidified.
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References
Jiregna, I. T., & Sirata, G. (2020). A review of the vehicle suspension system. Journal of Mechanical
and Energy Engineering, 4(2), 109–114. https://doi.org/10.30464/jmee.2020.4.2.109
Mongi, M. El, Gaid, B., Ela, A. C. ¸, & Kocik, R. (n.d.). Distributed control of a car suspension
system.
Sammier, D., Sename, O., & Dugard, L. (2003). Skyhook and H8 Control of Semi-Active
Suspensions: Some Practical Aspects. Vehicle System Dynamics, 39(4), 279–308.
https://doi.org/10.1076/vesd.39.4.279.14149
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