Mobile Robot Design Using ARM7

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2 Νοε 2013 (πριν από 3 χρόνια και 9 μήνες)

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Mobile Robot Design Using ARM7


Dr. Anand A Bhaskar, Mrs. Seema Oza Bhaskar, and Dr. H. N. Pandya

Email:

anand.bhaskar@spsu.ac.in, seemamyfrn@gmail.com, hnpandya@yahoo.com,



Dr. Anand A Bhaskar is Assistant Professor, ECE Department, SPSU, Udaipur
. Mrs. Seema Oza Bhaskar is a Research
Scholar in Department of Electronics, Saurashtra University, Rajkot. She is working under guidance of Dr. H. N. Pandya in
the field of Robotics. Dr. H. N. Pandya is Head of Department of Electronics, Saurashtra Univer
sity, Rajkot.


Abstract

-

This paper presents the design and development of autonomous mobile robot using LPC2138 robot control
panel board.
Also describes the architecture of robots such as software and hardware requirements. In this paper we
give the det
ail discussion about the autonomous robotics, design, control and applications. This paper presents design
concepts and guidelines for implementing an autonomous robot. This will provide a perfect plat
-
form for the
academicians as well as students to start

with the design and implementation of autonomous wheeled robots using
ARM7 family of microcontrollers.



Keywords
-

Robotics, Embedded Systems, Autonomous Robotics, Wheeled Mobile Robots, Design Techniques.



I

INTRODUCTION

Mobile robots are generally those robots which can move from place to place across the ground. Mobility
gives

a robot a much greater flexibility to perform new, complex, exciting tasks. The world does not have to be
modified to bring all needed items withi
n reach of the robot. The robots can move where needed. Fewer robots
can be used. Robots with mobility can perform more natural tasks in which the environment is not designed
especially

for them. These robots can work in a human
centered

space and cooperat
e with men by

sharing a
workspace together
. [
1
]

A mobile robot needs locomotion mechanisms that enable it to move unbounded throughout its environment.
There is a large variety of possible ways to move which makes the selection of a robot’s approach to loc
omotion
an important aspect of mobile robot design. Most of these locomotion mechanisms have been inspired by their
biological counterparts
who

are adapted to different environments and purposes.

[
1
],

[
2
] Many biologically
inspired robots walk, crawl, slit
her, and hop.

In the presented work our focus is on wheeled mobile robot using
LPC2138 robot control panel board.
With application in the robotics and automation, more and more

it becomes
necessary the development of applications based on

methodologies
that facilitate future modifications, updates
and

enhancements in the original projected system. This project

presents a conception of mobile robots using
rapid prototyping,

distributing the several control actions in growing levels of

complexity and compu
ting
proposal oriented to embed systems

implementation. This mobile robot will
move independently

and also be
able to

control the speed.
We w
ould like to construct a mechanically simple

three wheeled
robot model, which
can
navigate by its own

and according
ly should able to control the speed

of motor.


Wheeled mobile robots (WMRs) are more energy efficient than legged or treaded robots on hard, smooth surfaces
[Bekker60, Bekker691; and will potentially be the first mobile robots to find widespread applicatio
n in industry,
because of the hard, smooth plant floors in existing industrial environments. WMRs require fewer and simpler parts
and are thus easier to build than legged or treaded mobile robots. Wheel control is less complex than the actuation of
multi
-
j
oint legs, and wheels cause minimal surface damage in comparison with treads.

The mobile robot consists of many units:


mechanics (chassis, housing, wheels)


electromechanical parts


sensors

Robots carry out many various tasks. During these tasks the
robot moves and orients. While navigating, it uses signals
from the environment and the contents of its own memory to make the correct decisions. This form of navigation may
be manifold depending on the given task and problem. Often the goal can be sensed,

there is no obstacle between the
goal and the robot, but there are numerous times when this is not the case, then the marking points must be sensed and
the route known. In order for the robot to be able to do this, it must contain two main components:

• D
rive, motion and

• control, direction.

The
LPC213
8

are based on a 16/32 bit ARM7TDMI
-
S™ CPU with real
-
time emulation and embedded trace
support, together with 128/512 kilobytes (kB) of embedded high speed flash memory. A 128
-
bit wide memory
interface and
unique accelerator architecture enable 32
-
bit code execution at maximum clock rate. For crit ical
code size applications, the alternative 16
-
bit Thumb Mode reduces code by more than 30% with minimal
performance penalty. With their compact 64 pin package, lo
w power consumption, various 32
-
bit timers, 4
-

channel 10
-
bit ADC, USB PORT,

PWM channels and 46 GPIO lines with up to 9 external interrupt pins these
microcontrollers are particularly suitable for industrial control, medical systems, access control and po
int
-
of
-
sale.
[5]

With a wide range of serial communications interfaces, they are also very well suited for
communicat ion gateways, protocol converters and embedded soft modems as well as many other general
-
purpose applications.

In presented work LPC2138 is
used as the heart of the mobile robot.


II

WHEELED MOBILE ROBOT

A robot capable of locomotion on a surface solely through the actuation of wheel assemblies mounted on the robot
and in contact with the surface. A wheel assembly is a device which provides o
r allows relative motion between its
mount and a surface on which it is intended to have a single point of rolling contact.

The simplest cases of mobile robots are wheeled robots, as shown in Figure 1. Wheeled robots comprise one or more
driven wheels (dra
wn solid in the figure) and have optional passive or caster wheels (drawn hollow) and possibly
steered wheels (drawn inside a circle). Most designs require two motors for driving (and steering) a mobile robot. The
design is also steered. It requires two mo
tors, one for driving the wheel on the left
-
hand side of Figure 1 has a single
driven wheel that and one for turning. The advantage of this design is that the driving and turning actions have been
completely
separated by using two different motors. The rob
ot design in the middle of Figure 1 is called “differential
drive” and is one of the most commonly used mobile robot designs. The combination of two driven wheels allows the
robot to be driven straight, in a curve, or to turn on the spot. Finally, on the r
ight
-
hand side of Figure 1 is the so
-
called
“Ackermann Steering”, which is the standard drive and steering system of a rear
-
driven passenger car. We have one
motor for driving both rear wheels via a differential box and one motor for combined steering of b
oth front wheels.






Figure 1: Wheeled Robots


III

HARDWARE DESCRIPTION OF MOBILE ROBOT



In the presented work
a

three wheeled mobile robot is controlled by ARM7 family of microcontroller.
Within the proposal of mobile robotics
platform, the

use of
LPC2138

Controller, with control software

specially

d
eveloped for the necessary applications is considered using

embedded c

to design, simulation, and

v
erification
with

KEIL IDE
, we convert the model to function prototyping

using
LPC2138 robot control panel

board

and
three wheeled robot base.

Figure 2 shows the block diagram of mobile robot.










Figure 2: Block diagram of mobile robot.

This system included both hardware and software development.
Using the Keil IDE software design and
dev
elopment is done in embedded c which
is
most efficient than assembly language programming. To program
the microcontroller flash magic utility software is

used.

A small turning the wheels program has been
implemented in the
LPC2138
robot control panel board.

The board is interfaced with L298N motor drive
module.
This chip is much more widely used and adopted in applications. The main difference between the
chips is that the L298
N

will require two PWM inputs in

order to drive the motor fast, slow, forwards or
backwards.

The module is designed to work in PWM and non PWM mode of operation.

Table 1 shows the
logic inputs to activate the L298N chip.


FUNCTIONS

I
NPUTS (E1E2M1AM1BM2AM2B)

Forward

111010

Reverse

110101

Left

010010

Right

101000

Table 1: Logic inputs to activate the L298N chip.

Mobile robot base along with robot control panel board and motor driver is shown in Figure 3.


LPC2138 µc

Sensor Interface

PC Interface

H
-
Bridge

DC Motor


Figure
-
3:

Mobile robot base with LPC2138 board and motor driver module.


IV

APPLICATIONS OF AUTONOMOUS ROBOTICS

Low complexity of current application. The control program is extensively tested on the robot in order to adjust
poor reaction, neural network, genetic algorithms and neuro
-
fuzzy approach. Robot must be sold in numerous
copies to customers who will read a
short set of recommendations. Application is energy autonomy which is
currently supported by solar cells. Power Requirement is negligible for sensor reading. Current limitations in
energy autonomy naturally favor “White
-
Collar” applications of autonomous r
obots such as surveillance. [
4
]


V

CONCLUSION AND FUTURE WORK


Robotic platforms engineering are a necessary in teaching and

research institutions for knowledge consolidation
in several

teaching and research, such as modeling, control, automation,

power sy
stems, embedded electronics
and software. The use

of the mobile robots for this purpose appears to be quite an

attractive solution. It allows
the integration of several

important areas of knowledge and a low cost solution, which

has already been adopted
wi
th success by other research

institutions. The main objective of this work was to propose a

generic platform
for a robotic mobile system, seeking to

obtain a support tool for under
-
graduation and graduation

activities.

Another objective was to gather
knowledge in the

mobile robotic area, aiming at presenting practical solutions

for industrial problems, such as maintenance, supervision and

transport of materials.

The mobile robot systems
have more and more

importance these days, so dealing with them in
the higher

education is necessarily.

Autonomous mobile robots can be

used to deliver parts in factories, being complementary

platforms in a

security system and they also can be used in

hazardous areas where humans can not stay.

The wireless channel
may
also be added to increase system

flexibility. The proposed framework remains simple and user

friendly;

additionally it provides enough flexibility for the

specific application. Our approach can be extended to more


d
emanding applications by adding more
i
nterfacing
modules, or other

peripheral interfaces. Currently
we are

working on the

development of
universal

robot

control panel board

with the same modules
which are discussed
above.


V
I

References


[1
] Robert Holmberg, “Design and Development of Powered
-
Castor Holonomic

Mobile Robots”, Stanford University, 2000

[2
] Roland Siegwart, Illah R. Nourbakhsh “Introduction to Autonomous Mobile Robots”, The MIT Press,

Massachusetts Institute of Technology,
Cambridge, Massachusetts, 2004

[3]
István Matijevics: Microcontrollers, Actuators and Sensors in Mobile Robots, in Proceedings of 4
th
Serbian
-

Hungarian Joint Symposium on Intelligent Systems (SISY 206) September 29
-
30, 2006, Subotica, Serbia.

[4]
“Introdu
ction to Robotics Technology” www.ibm.com.

[5]

LPC2138 controller specification,

www.NXP.com

[6]
UM10139: volume 1: user manual for lpc213x.