CHAPTER 1:

Introduction:

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A proportional–integral–derivative
controller (PID controller or three term controller) is a control loop feedback
mechanism widely used
in industrial
control systems and
a variety of other applications requiring continuously modulated control. A PID
controller continuously
calculates an error value   as the
difference between a desired set point (SP) and a measured process variable
(PV). It applies a correction based on proportional, integral, and derivative
terms (denoted P, I, and D respectively) which give the controller its name. In practical terms it automatically applies
accurate and responsive correction to a control function. An everyday example
is the cruise
control on a road
vehicle; where external influences such as gradients would cause speed changes,
and the driver has the ability to alter the desired set speed. The PID
algorithm restores the actual speed to the desired speed in the optimum way,
without delay or overshoot, by controlling the power output of the vehicle’s
engine.

1.1      
Overview:

Proportional-Integral-Derivative
(PID) control is the most common control algorithm used in industry and has
been universally accepted in industrial control. The popularity of PID
controllers can be attributed partly to their robust performance in a wide
range of operating conditions and partly to their functional simplicity, which
allows engineers to operate them in a simple, straightforward manner As
the name suggests, PID algorithm consists of three basic coefficients;
proportional, integral and derivative which are varied to get optimal response.

 

1.2       
Project Idea:

The main idea of
this project is to control the speed of motor using PID controller. The speed control
of a motor is frequently used in industrial applications, robotics, home
appliances, etc. In this report, we have implemented a DC motor speed control
system. The idea of a speed control system is to maintain the speed of the
motor at the desired value under various conditions. DC motor is a nonlinear
device and its speed varies due to change in load demand, disturbances
etc.  PID controller algorithm is

implemented which
is a popular controller in industries.

1.3      
Purpose of the
Project:

The primary motivation behind this
undertaking is to control the DC engine by utilizing the three control terms of
relative, fundamental and subsidiary which impact the controller yield to apply
exact and ideal control. The DC engine has been prevalent in the business
control zone for quite a while, in light of the fact that they have numerous
great qualities. It is broadly utilized as a part of speed control frameworks
which require high control necessities, for example, moving plant, twofold
hulled tanker, high accuracy computerized instruments and so forth.

 

1.4       Project Specifications:

The speed control
system was implemented for a Permanent Magnet DC Motor (PMDC). The PMDC
consists of rotor or armature and a stator, which is a permanent magnet. There
are two ways of speed control for a DC motor

·        
Field Control:   In this method, the field current or current
through stator is varied to control the speed of the motor.

·        
Armature Control:  In this method, the armature voltage is
varied to control the speed of the motor.

 

DC
Motor Specifications:

1.       12V Permanent Magnet DC Motor

2.       Rated current: 200mA at no load, 290mA at full
load

3.       Torque: 50gm-cm

4.       Maximum speed: 2500 rpm

Speed
Measurement:

The
optical change is utilized to quantify the speed of engine. It is a LED and
photograph transistor match, which creates beats comparing to engine speed.

H21A1
optical switch is made by Fairchild semiconductors.

H21A1
Specifications:

1. If (max) = 50 mA.

2. Ic (max) = 20 mA.

3.
Voltage (rev) = 6 V (max)

1.5      
Project Plan

Four weeks were given to complete the project
of PID controller. So it was divided  in
four section containing four weeks.

1.6      
Report
Organization

After making this project, report was divided
in 6 chapters. Chapter one consists of introductory things about our project.
Second chapter is about literature of our project like theories based on PID
controller .Third chapter is of project design and its implementation. Fourth
is about Tools and techniques used in our project. Fifth one is of Result and
evaluation last one that is sixth is about conclusion, references and
appendix. 

 

CHAPTER 2

LITERATURE REVIEW

2.1.                
Background:

DC
engines are broadly utilized as a part of mechanical applications, robot
controllers and home apparatuses, in light of their high unwavering quality,
adaptability and minimal effort, where speed and position control of engine are
required. This task manages the execution assessment of various sorts of
ordinary controllers and savvy controller actualized with an unmistakable goal
to control the speed of independently energized DC engine.

PID
controllers are generally utilized for engine control applications due to their
basic structures and intuitionally intelligible control calculations.
Controller parameters are for the most part tuned utilizing Ziegler-Nichols
recurrence reaction technique. Ziegler-Nichols recurrence reaction strategy is
typically used to modify the parameters of the PID controllers. Be that as it
may, it is expected to get the framework into the swaying mode to understand
the tuning strategy. Be that as it may, it’s not generally conceivable to get
the majority of the mechanical plants into swaying.

In
process control, display based control frameworks are essentially used to get
the coveted set focuses and reject little outer unsettling influences. The
inside model control (IMC) outline depends on the way that control framework
contains some portrayal of the procedure to be controlled and a flawless
control can be accomplished.

2.2.                
Related Technologies

Optimal
Design of PID Controller for the Speed Control of DC Motor by Using Met
heuristic Techniques:

In this work, a PID controller design for speed
control of DC motor is presented. In the first place, the outline through
traditional systems like Zeigler-Nichols and Cohen-Coon strategies is displayed
for building up a standard. At that point, six metaheuristic improvement
calculations are utilized to locate the most ideal parameters of PID controller
subjected to minimization of a cost work and among these three of the half and
half procedures are utilized to set up the predominance of crossover met
heuristic methods over the others.

2.3.                
Related Projects:

Analogue Electronic
Controllers:

Electronic
simple PID control circles were regularly found inside more intricate
electronic frameworks, for instance, the head situating of a plate drive, the
power molding of a power supply, or even the development recognition circuit of
a cutting edge seismometer. Discrete electronic simple controllers have been to
a great extent supplanted by advanced controllers utilizing microcontrollers or
FPGAs, to execute PID calculations. In any case, discrete simple PID
controllers are as yet utilized as a part of specialty applications requiring
high-transmission capacity and low-commotion execution, for example,
laser-diode controllers.

 

2.4.                 
Limitations of Existing Work:

PID controllers are material to many
control issues, and regularly perform palatably with no upgrades or just coarse
tuning, they can perform inadequately in a few applications, and don’t when all
is said in done give ideal control. The essential trouble with PID control is
that it is an input control framework, with consistent parameters, and no
immediate information of the procedure, and along these lines general execution
is responsive and a trade off. While PID control is the best controller in an
eyewitness without a model of the procedure, better execution can be acquired
by plainly displaying the performing artist of the procedure without falling
back on a spectator.

PID controllers, when utilized alone,
can give poor execution when the PID circle increases must be lessened with the
goal that the control framework does not overshoot, waver or chase about the
control set point esteem. They likewise experience issues within the sight of
non-linearities, may exchange off direction versus reaction time, don’t respond
to changing procedure conduct.

2.5.                
Problem Statement:

The
problem statement is that development in the varying assortment and power
estimations of semiconductors has incited quick enhancements of basic control
devices for DC. Nowadays, manual controller is similarly not helpful in the
development time. Operation cost as for controller got thought from mechanical
field. Remembering the true objective to limit cost and time, making a
controller in light of PC since it is flexible proposed. The customer can
screen it’s system at certain place without need to heading off to the plant
(machine) especially in mechanical execution. From that, the work can be
diminished and spare with PC which is more correct and tried and true. The
basic electronic devices can be arranged using power electronic control device
to make a speed controller structure. This has driven the authorities to
consider the framework and usage of a power electronic control contraption to a
DC engine. The adaptable PID controller is planned to the point that it can be
used to beat the issue in industry get a kick out of the opportunity to avoid
machine hurts and to avoid direct rising time and high overshoot.

2.6.                
Summary:

This
project is made to control the speed of DC motor by using a PID controller. Although
a PID controller has three control terms, some applications use only one or two
terms to provide the appropriate control. This is achieved by setting the
unused parameters to zero, and is called a PI, PD, P or I controller in the
absence of the other control actions. PI controllers are fairly common, since
derivative action is sensitive to measurement noise, whereas the absence of an
integral term may prevent the system from reaching its target value.

Chapter
3

PROJECT DESIGN AND IMPLEMENTATION

This project was about to control the speed
of DC motor using PID controller. To control the speed of
DC motor using PID four circuits are used, the first one is the subtractor,
PID, Encoder (motor driver) and FVC (Frequency to voltage controller) circuit.

3.1.       
Proposed Design Methodology

At first we have given the variable
reference and used subtractor to generate error. Then there was a circuit of
PID and after PID there was an adder which added up the three circuits P, I and
D. After adder there was a motor driver and motor encoder and at last there was
a Frequency to Voltage converter. As the name indicates it converts the
frequency into voltage.

 Analysis Procedure

3.2.       
Implementation Procedure

Firstly, block diagram was made and then that block diagram was designed
on proteus. Below given figure was used to complete the project.

 

 

 

 

 

3.3.       
Design of the Project Hardware

 

·        
Schematic diagram of the circuit is:

 

 

 

 

 

 

 

Figure 2 : Schematic Diagram

 

Simulation

 

 

 

 

 

 

 

 

 

 

Figure 3: Simulation

 

 

3.4.       
 Details of Final Working Prototype 

With the utilization of minimal effort basic
ON-OFF controller just two control states are conceivable, as completely ON or
completely OFF. It is utilized for restricted control application where these
two control states are sufficient for control objective. However wavering
nature of this control restrains its use and subsequently it is being supplanted
by PID controllers.

PID controller keeps up the yield with the
end goal that there is zero mistake between process variable and set
point/wanted yield by shut circle operations. PID utilizes three fundamental
control practices that are clarified beneath.

3.4.1.                      
 P- Controller: 

 

 

 

 

 

Output of Proportional or P- controller is directly proportional to current
error e (t). It compares desired or set point with actual value or feedback
process value. The resulting error is multiplied with proportional constant to
get the output. The controller output is zero if the error value is zero.

3.4.2.                      
P-Controller Response

This controller requires biasing or manual reset when used alone. This
is because it never reaches the steady state condition. It provides stable
operation but always maintains the steady state error.  Speed of the
response is increased when the proportional constant Kc
increase

3.4.3.                      
Integral Controller

 

 

 

 

3.4.4.                      
PI controller

Due to limitation of
p-controller where there always exists an offset between the process variable
and set point, I-controller is needed, which provides necessary action to
eliminate the steady state error.  It integrates the error over a period
of time until error value reaches to zero. It holds the value to final control
device at which error becomes zero.

Integral control decreases
its output when negative error takes place. It limits the speed of response and
affects stability of the system. Speed of the response is increased by
decreasing integral gain Ki.

While using the PI
controller, I-controller output is limited to somewhat range to overcome the
integral wind up conditions where integral output goes on increasing even at
zero error state, due to nonlinearities in the plant.

                                                   

3.4.5.                      
 Derivative-Controller

Integral -controller doesn’t have the capability to predict the future
behaviour of error. So, it reacts normally once the set point is changed.
D-controller overcomes this problem by anticipating future behaviour of the
error. Its output depends on rate of change of error with respect to time,
multiplied by derivative constant. It gives the kick start for the output
thereby increasing system

At last, we got the desired system by combining the above mentioned
circuits. Different manufactures design different PID algorithms.

 

 

 

 

 

3.5.       
Summary

In
the end we concluded that speed of DC motor can be controlled by PID
controller. So, firstly by changing P-factor or proportional factor it can be
seen that how overshoot of the
signal can be changed and rise time of the signal got changed.

 

 

 

 

 

 

 

 

 

Chapter 4

TOOLS AND TECHNIQUES

Tools and techniques of
this project are discussed in this project.

4.1 Hardware Tools

Four
circuits are used in this project i.e. subtractor, PID, encoder and FVC.

1.      Resistors

2.      Capacitors

3.      DC
motor

4.      Photo
diode

5.      Transistor

6.      Switch

7.      Feedback

8.      Variable
resistor

9.      ICs

10.  Connectors

11.  PCB
sheet

12.  Soldering
machine

13.  Wires

14.  Breadboard

 

 

4.1.                    
Resistors:

Resistor
is a passive device used to resist the flow of current. Its schematic symbol is

 

 

Resistors
are found in different values according to their color coding.

 

 

 

Figure 8: Resistors

 

4.2.                    
 Capacitor:

Capacitor
is a device used to store electric charges. It consists of pairs of conduction
separated by an insulator.  Capacitors
are used to smooth the wave or to remove noises from the wave.

 

 

4.3.                    
DC Motor

A DC motor is
an electrical machine that converts electrical energy into mechanical energy.
The most common types rely on the forces produced by magnetic fields. Nearly
all types of DC motors have some internal mechanism, either electromechanical
or electronic, to periodically change the direction of current flow in part of
the motor.

 

4.4.                    
Photo Diode: 

A photodiode is
a semiconductor device that converts light into an electrical current.
Generation of current is due to absorption of photon in the photodiode. Photodiodes have large or
small surface area with optical fiber in it.

 

 

 

 

4.5.                    
 Transistor:

A
semiconductor device which is used to amplify or switch electronic signals and
electrical power is called transistor. It is composed of semiconductor material
usually with at least three terminals for connection to an external circuit.
The transistor that used in this project is BC337. Sample of a transistor is
given below:

 

 

4.6.                    
Integrated Circuit:

An integrated
circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on
one small flat piece (or “chip”) of semiconductor material, normally
silicon. In  this  project LM358 is used. It has 8 pins. It has
two operational amplifiers. These operational amplifiers are used as
proportional, integral and derivative. Frequency to voltage controller is also
made from these IC’s.

 

 

4.7.                   
 Software

 We have used Proteus 8.0 to simulate the design. In
Proteus circuits can be designed, simulate. It is a very useful software to
make PCB layout of circuit.

 

Chapter 5

Projects Results and Evaluation

This
project consists of different parts i.e. Frequency to voltage converter,
Subtractor, Adder, Motor Driver, Reference signal. After completing this
project, this project is able to control the speed of DC motor.

5.1.        
Presentation of Findings:

5.1.1. 
Proportional Control:

The proportional term produces an output value that is proportional to the
current error value. The proportional response can be adjusted by multiplying
the error by a constant Kp, called the proportional gain
constant.

 

{displaystyle P_{ ext{out}}=K_{ ext{p}}e(t).}

 

 

 

 

 

 

5.1.2.  Integral Control:

The contribution from the integral term is
proportional to both the magnitude of the error and the duration of the error.
The integral in a PID controller is the sum of the
instantaneous error over time and gives the accumulated offset that should have
been corrected previously. The accumulated error is then multiplied by the
integral gain (Ki) and added to the controller output.

 

 

 

 

 

 

5.1.3.  Derivative Control:

A derivative term does not consider the error (meaning it
cannot bring it to zero: a pure D controller cannot bring the system to its set
point), but the rate of change of error, trying to bring this rate to zero. It
aims at flattening the error trajectory into a horizontal line, damping the
force applied, and so reduces overshoot (error on the other side because too
great applied force). Applying too much impetus when the error is small and is
reducing will lead to overshoot. After overshooting, if the controller were to
apply a large correction in the opposite direction and repeatedly overshoot the
desired position, the output would oscillate around the set point either a constant, growing, or
decaying sinusoid. If the amplitude of the oscillations
increases with time, the system is unstable. If they decrease, the system is
stable. If the oscillations remain at a constant magnitude, the system is marginally
stable.

5.2.        
Hardware Results:

 

 

 

 

 

 

 

 

 

5.3.        
Limitations:

This project, when used alone, can give poor
performance when the PID loop gains must be reduced so that the control system
does not overshoot, oscillate or hunt about the
control setpoint value. They also have difficulties in the presence of
non-linearities, may trade-off regulation versus response time, do not react to
changing process behavior (say, the process changes after it has warmed up),
and have lag in responding to large disturbances.

5.3.1. 
Linearity:

Another problem faced with this
project is that they are linear, and in particular symmetric. Thus, performance
of PID controllers in non-linear systems is variable.

5.3.2. 
Noise in Derivative:

A problem with the
derivative term is that it amplifies higher frequency measurement or
process noise that can cause large amounts of change in the output.
It is often helpful to filter the measurements with a low-pass filter in order to remove higher-frequency noise components.

5.4.        
Recommendations and Future Work:

·        
It is recommended a high enough sampling
rate, measurement precision, and measurement accuracy should installed to
achieve adequate control performance.

·        
New method for improvement of PID
controller should introduced to increase the degree of freedom by using fractional order.

·        
The order of the integrator and
differentiator should add to increase flexibility to the controller.

This project is mainly
consists of three parts which has performed their work efficiently.

The goal of project; to
control the speed of DC motor is achieved.

 

 

CHAPTER 6:

Conclusions

It is concluded that
PID controller can control the speed of DC motor. PID controllers are commonly used to
regulate the time-domain behavior of many different
types of dynamic plants. These controllers are extremely popular because
they can usually provide good closed-loop response characteristics,
can be tuned using relatively simple design rules, and are easy
to construct using either analog or digital components.

 

 

 

 

 

 

 

Chapter 7

References

1      L. dos
Santos Coelho, “Tuning of PID controller for an automatic regulator voltage
system using chaotic optimization approach,” Chaos, Solitons and Fractals,
vol. 39, no. 4, pp. 1504–1514, 2009.

2      R. C. Division, B. Atomic, and C.
Republic,

3      C. Engineering, “DC Motor Speed Control
using Experience Mapping Based Prediction Controller ( EMPC ),” pp. 533–538,
2017.

4      R. V. Jain, M. V. Aware, and A. S.
Junghare, “Tuning of Fractional Order PID Controller U sing Particle Swarm
Optimization Technique for DC Motor Speed Control,” vol. 6, no. 2, pp. 6–9,
2014.

5      P. M. Meshram and R. G. Kanojiya, “Tuning
of PID Controller using Ziegler-Nichols Method for Speed Control of DC Motor,” 2013
IEEE Int. Conf. Control Appl., pp. 117–122, 2012.

6      M. J. Neath, A. K. Swain, U. K. Madawala,
and D. J. Thrimawithana, “An optimal PID controller for a bidirectional
inductive power transfer system using multiobjective genetic algorithm,” IEEE
Trans. Power Electron., vol. 29, no. 3, pp. 1523–1531, 2014.

7      S. K. Suman and V. K. Giri, “Speed Control
of DC Motor Using Different Optimization Techniques Based PID Controller,” IEEE
Int. Conf. Eng. Technol., vol. 2, no. 7, pp. 6488–6494, 2012.

8      L. Syafaah, I. Pakaya, D. Suhardi, and M.
Irfan, “PID Designs Using DE and PSO Algorithms for Damping Oscillations in a
DC Motor Speed,” no. September, pp. 19–21, 2017.

9      P. S. Vikhe, N. Punjabi, and C. B. Kadu,
“DC Motor Speed Control Using PID Controller In Lab View,” no. 3, pp. 38–41,
2015.

10    S. B. Prusty, K. K. Mahapatra, U. C. Pati,
and S. Padhee, “Comparative performance analysis of various tuning methods in
the design of PID controller,” Michael Faraday IET Int. Summit 2015, p.
8 (6 .)-8 (6 .), 2015.

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