1. RV College of
Engineering®
Go, change the world
DEPARTMENT OF
MECHANICAL ENGINEERING
ENGINEERING
VIBRATIONS AND CONTROL SYSTEMS – 18ME72
CONTROL SYSTEMS IN AUTOMOBILES
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SAMPREET DINAKAR NAYAK – 1RV19ME095
SARTHAK DAVE – 1RV19ME096
SATISH M - 1RV19ME097
SHARANABASU D KOTTALAGI - 1RV19ME098
2. CONTROL SYSTEMS
A control system is a system of devices or set of devices, that manages, commands, directs or regulates the behaviour of
other device(s) or system(s) to achieve the desired results. In other words, it’s a combination of various elements connected as
a unit to direct or regulate itself or any other system in order to provide a specific output. We know controlling is basically
known as the act of regulating or directing so Control System is used to direct the functioning of a physical system to carry
out the desired objective.
Majorly the control system is divided into two major domains:
* Controlled process: The part of the system which requires controlling is known as a controlled process or plant.
* Controller: The internal or external element of the system that controls the process is known as the controller.
Further, some other aspects are as follows:
* Input: For every system to provide a specific result, some excitation signal must be provided. This signal is usually
given through an external source. So, the externally provided signal for the desired operation is known as input.
* Output: The overall response of the system achieved after application of the input is known as output.
* Disturbances: Sometimes even on providing required input, the system fails to generate the desired output. So the
signal that causes variation in the desired output is known as disturbances.
Now, disturbances can be of two types depending on its origin. If the disturbance is generated from the system itself
then it is known as internal disturbances. While if the disturbance is generated from somewhere outside the system and
unknowingly acting as another input to the system causing an adverse effect on the output. Then it is known as external
disturbances.
3. NEED OF CONTROL SYSTEMS & TYPES
As the human civilized is being modernized day by day the
demand of automation is increasing accordingly. Automation
highly requires control of devices. Control system ensures that
there is a strategic method to improving productivity and
enhancing the best practices of your company. It eliminates the
redundant manual controls & human errors saving significant
amount of money.
There are two types of Control Systems:
1)Open loop control system:
Any physical system which does not automatically correct the
variation in its output is called an open loop system or control
system in which the output quantity has no effect upon the input
quantity are called open loop control system. This means that
output is not feedback to the input for correction.
Here, the output can be varied by varying the input. But due to
external disturbances, the system output may change. When the
output changes due to disturbances, it is not followed by changes
in input to correct the output. In open loop systems, the changes
in output are corrected by changing the input manually. 3
4. 2)Closed loop control system:
Control systems in which the output has an effect upon the input quantity in order to maintain the desired output value are
called closed loop systems.
The open loop system can be modified as closed loop system by providing a feedback. The provision of feedback automatically
corrects the changes in output due to disturbances. Hence the closed loop system is also called automatic control system. The
general block diagram of an automatic control system is shown in the figure below. It consists of an error detector, a controller,
plant (open loop system) and feedback elements.
The reference signal (or input signal) corresponds to the desired output. The feedback path elements sample the output and
convert it to the reference signal type. The feedback signal is proportional to the output signal and it is fed to the error detector.
The error signal generated by the error detector is the difference between the reference signal and the feedback signal. The
controller modifies and amplifies the error signal to produce better control action. The modified error signal is fed to the plant to
correct its output.
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5. REQUIREMENTS OF GOOD CONTROL SYSTEMS
1. Sensitivity: Sensitivity is the ability to show instant variation in output whenever there
exists any change in input. There are external parameters like temperature change or
other atmospheric conditions that hinder the actual performance of the system. So a
control system must be sensitive only to the actually applied input and not to other
external parameters.
2. Stability: The system must be stable while providing the output without showing
fluctuation with time.
3. Bandwidth: The permissible frequency range of the system specifies its bandwidth. A
good frequency response the system must possess high bandwidth.
4. Noise: Unwanted signals that hinders the performance of the system adversely is known
as noise. A good control system must show the least susceptibility towards the noise.
5. Accuracy: The system must produce accurate output, so as to have least chances of error
in the achieved output value.
6. Speed: Speed defines the processing time of the system within which the specified
output is achieved. So the speed of the system must be high enough to deliver the output
timely. 5
