Bi directional speed control of dc motor and stepper motor through mat lab using pic micro controller

IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 02 Issue: 11 | Nov-2013, Available @ http://www.ijret.org 686
BI DIRECTIONAL SPEED CONTROL OF DC MOTOR AND STEPPER
MOTOR THROUGH MAT LAB USING PIC MICRO CONTROLLER
Ozwin Dominic Dsouza1
, Manjunathababu. P2
, Babu Naik3
1
BMS Institute of Technology, Bangalore, India
ozwindsouza@gmail.com, manjubabup@gmail.com
Abstract
In any industry speed control of an electric drive system is very critical and crucial. Every designer aims at achieving a control
methodology having high degree of precision. But industry needs are ever evolving in nature. Hence it is very much essential that
along with conventional speed control mechanisms we must also have simple interactive graphical based control strategies. Several
algorithms/methodologies have been developed over the years to achieve speed control of motors. In this context by encompassing the
usability of Mat Lab, work has been done to control the speed of stepper motor and DC motor using microcontroller. Microcontroller
is programmed to achieve bi directional speed control. The main objective of this work is to develop the graphical user interface of
motor control through mat Lab guide and the interface of the same with hardware via serial communication. PIC is used as the
controller.
Keywords— DC, PIC, µC, AC, GUI, IC
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1. INTRODUCTION
DC motors are widely used in adjustable speed drives and
position control applications. In DC motor speeds below its
base speed is controlled by armature voltage control method [1]
[2]. Speeds above base speed are achieved by encompassing
field flux control method. Speed controls of DC motors are
much cheaper and simpler as compared to AC motors. This is
mainly because in DC motor speed control only two control
parameters are sufficient (voltage or flux). On the contrary an
AC motor speed control requires three control parameters.
A stepper motor is a marvel in simplicity [1]. It is basically an
electromechanical device which converts electrical pulses into
discrete mechanical movements. Unlike DC motors it has no
brushes and contacts and is a synchronous motor with the
magnetic field electronically switched to rotate the armature
magnet. The essential function of a stepper motor is to translate
switching excitation changes into precisely defined increments
of rotor position. A stepper motor can divide a full rotation into
a large number of steps, for example 200 steps. The motor thus
can be made to rotate through a precise angle. The sequence of
applied pulses is directly related to the direction of motor
rotation. There are different types of stepper motors; namely (i)
permanent magnet (ii) variable reluctance (iii) Hybrid motors.
The basic block diagram of stepper motor is shown in figure 1
below.
Fig 1 Block diagram of stepper motor
Speed control of DC motor and stepper motor through Mat Lab
using PIC microcontroller (µC) [3] is an initiative taken to
emphasize the use of two types of motors( stepper and DC
motor) together. PIC µC used here enables the user to code in
such a way that the DC and stepper motors rotate in forward
and reverse direction at any given point of time as and when
specified by the user through keys. At the same time user has
an option of manual intervention in direction of rotation, as PIC
µC is designed to operate in both auto and manual mode.
It is a proven fact that proven over the years that MAT Lab is a
powerful design/simulation tool. It gives greater flexibility to a
designer to analyze the circuit/product before the actual
implementation. Signals required to run in auto mode are
generated through Mat Lab using Graphical user interface
(GUI) [4]. GUI facilitates the simple coding technique through
which signals could be sent. This work describes the GUI codes
for sending signals to hardware through parallel port under the
supervision of µC. This type of speed control approach is
highly useful in applications where precise speed control is
required for example in computer numeral control (CNC).

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2. HARDWARE DESCRIPTION
Detailed block diagram of the project is as shown in figure 2
below. It mainly consists of the following parts.
A. DC Motor
A dc motor works based on the principle of electromagnetic
induction Here a DC motor having 9-12V, 2000 RPM rating is
used. DC motor is connected to PIC µC via a dual H-Bridge
motor driver integrated circuit. Motor drivers acts as current
amplifiers. They take low-current control signal and provide
high current signals. The higher current signals eventually drive
the motor in the designed program sequence.
Fig 2 Block diagram of the project
B. Stepper Motor:
A stepper motor having specification 12V, 1.8 Degrees is used
here. It is connected to PIC µC via stepper motor driver IC.
This IC basically takes the control signals from µC and in turn
takes controlling actions on stepper motor.
C. Buffer IC:
Buffer IC is also called as line driver IC. Buffer IC passes the
signal from one circuit to the other without any changes in
signals. The operating voltage rages from 2V to 6V.
D. H-Bridge Motor Control Circuit:
A very popular/simpler way of achieving speed control of a DC
motor is by using a single transistor based control. But the main
disadvantage of this control strategy is that, only uni-directional
speed control is possible. But in many applications it is
necessary to operate the motor in both directions; clockwise or
anticlockwise. A very good way of achieving this is to connect
the motor to a Transistor H-Bridge circuit. With this
arrangement Bi-directional DC motor operation becomes
possible.
2.1 Basic Bi-directional H-bridge Circuit:
Figure 3 shows the basic H-bridge circuit. It is named so
because the basic configuration of the four switches, transistors
resembles the letter H with the motor positioned in the center.
The transistor or MOSFET H-bridge is probably the most
commonly used Bi-directional DC motor control circuit. Which
uses complementary transistor pairs, both NPN and PNP in
each branch along with motor. The transistor operates in pairs
to control the motor.
From figure 3, control input A, operates the motor in one
direction; Forward rotation and input B operates the motor in
Reverse direction; Reverse rotation. Switching the transistors
ON or OFF in their diagonal pairs results in bi-directional
control of the motor. Then transistor TR1 is ON and transistor
TR2 is OFF, point A is connected to the supply voltage (+Vcc)
and if transistor TR3 is OFF
Fig 3 H-Bridge circuit
H-Bridge circuit and transistor TR2 is OFF, point A is
connected to the supply voltage (+Vcc) and if transistor TR3 is
OFF and transistor TR4 is ON, point B is connected to ground
(GND) terminal. Then the motor will rotate in one direction
corresponding to motor terminal A being positive and terminal
B being negative. If the switching states are reversed, then the
motor will operate in the reverse direction. The H-bridge truth
table for the motor operation is shown in Table 1.
It is important to note that Input A and Input B must not be kept
at High Logic. If not then the power supply terminals gets short
circuited and the fuse blows. IC L293D is used in this work as
motor driver IC. This IC is a dual H-bridge motor driver, so
with one IC, user can interface two DC motors which can be
controlled both in forward and reverse direction. For protecting

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the circuit from back emf output diodes are included within the
IC. This has made it a best choice for DC motor driver. Pin
configuration is shown in figure 4.
Table 1 H-Bridge truth table
Input A (TR1
and TR4)
Input B (TR2
and TR3)
Motor Function
0 0 Motor
Stops(OFF)
1 0 Motor rotes
forward
0 1 Motor rotates
reverse
1 1 Not Allowed
2.2 Stepper Motor Driver IC:
This IC is used to drive the current from the µC to the stepper
motor. Driver IC used here is ULN2803. It consists of eight
Darlington transistors with common emitters and integral
suppression diodes for inductive loads. Input to this circuit is
given from the PORT of the
Fig 4 Pin configuration
µC. Output of this IC is given to stator of stepper motor.
2.3 PIC microcontroller (µC):
PIC16F887 is used in this work. This µC encompasses RISC
architecture. Operating frequency is 0-20MHz. PIC µC
performs the job of a controller. This µC totally controls the
entire process. It is coded in such a fashion that both manual
and automatic speed control is possible.
3. SOFTWARE DESCRIPTION
Software part of this project consists of two parts (1) Coding of
µC (2) Creating GUI for speed control. Unique approach of this
project is that the GUI creation and the controlling through it.
Mat Lab supports wide range of applications, including signal
and image processing, communications, control design, test and
measurement etc.
GUI is a pictorial interface to a program. A good GUI can make
programs easier to use by providing them with a descriptive
appearance and with insightful controls like pushbuttons, list
boxes, sliders, menus so on and so forth. The GUI should
behave in an understandable and knowable manner, so that a
user knows what to anticipate when performs an action
example, like mouse click occurs on a pushbutton. The GUI
should initiate the action described on the label of the button.
Figure 5 shows the developed GUI for motor control.
Fig 5 GUI of Motor Control
Fig 6 Actual implementation of Motor Control
After laying out the GUI component and setting the property,
the GUI will look like as shown in figure 5. Finally ode is
written to implement the behavior associated with each call
beck function. This kind of programming is often called event-
driven programming. Actual view of the project is given in
figure 6.

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CONCLUSIONS
In this work a computer program has been developed for
programming and driving stepper and DC motors via the
parallel port of a PC; a GUI performing all defined motions
individually are also improved. In addition, the GUI allows
programmers to define the user defined functions. So, the
programmers can make stepper motors and DC motors to rotate
in all manners. The developed programs are tested with a
stepper motor of 1.80 step angle in forward and reverse with
speed variation modes. Also the developed program is tested
with a DC motor for forward and reverse motion control. Very
satisfactory results are obtained from experimental setup. The
program can be used in applications containing steeper and DC
motors performing complex motions. From the obtained results
it is concluded that speed control of DC motor and Stepper
motor can be used in robotic systems, DC drive systems, paper
printing mills, CNC machines.
FUTURE WORK
As a future expansion, work is under progress, so as to control
the motors using sensor less technique using faster µC or DSP.
Work is also under progress in the control software loop.
Design of Fuzzy control, neural network control, Adaptive
control algorithms are currently under progress.
ACKNOWLEDGMENT
The authors would like to thank Dr. S.C. Sharma, Chief Mentor
BMSIT and BMSSA for providing constant thrust/ inspiration
to achieve more. The authors also thank Prof. S.
Venkateswaran Principal BMSIT for his constant support. The
efforts of final year Electrical students while realizing this work
is also acknowledged.
REFERENCES
[1] A. E. Fitzgerald, Charles Kingsley Jr, Stephen Umans
“Electric Machinery” McGraw-Hill Higher Education, Sixth
Edition
[2] Bimal K Bose, “Power Electronics And Motor Drives:
Advances and Trends”. Academic Press, 2006 edition
[3] J. Petrovciv, S. Strmcnik,“A microcomputer based speed
controller for lift drives” IEEE Trans. Ind.Appl.,24(3), vol.34,
pp.487-498,1998.
[4] Mat Lab, Creating Graphical User Interfaces, Version 7,
The Mathworks Inc. Naticks/Ma, 2006.
BIOGRAPHIES
Ozwin Dominic Dsouza has received his masters from
National Institute of Engineering, Mysore, India. Currently
working as Assistant professor in the department of Electrical
and Electronics Engg at BMSIT Bangalore. His research
interests are in the field of electric drives and systems and
control systems, converter topologies and electrical machines.
Manjunatha Babu P obtained his B.E and M.E from
Visvesvaraya Technological University, Bangalore University.
Presently working as Assistant Professor in the Dept of
Electrical and Electronics Engineering at BMS Institute of
Technology, Bangalore, India. His interests are in the area of
power and Energy systems. Power System Operation and
Control, Power Transmission and Distributions System Studies,
FACTS Controllers.
Babu Naik Gugulothu, has received his masters from the
Indian Institute of Science (IISc) Bangalore, India. Currently
working as Assistant professor in the department of Electrical
and Electronics Engg at BMSIT Bangalore. His research
interests are in the field of Industrial drives and applications,
power systems, SMPS circuits, converter topologies and
electrical machines.

Bi directional speed control of dc motor and stepper motor through mat lab using pic micro controller

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Bi directional speed control of dc motor and stepper motor through mat lab using pic micro controller