Intelligent Mobile ROBOT Navigation Technique Using RFID Technique

stagetofuAI and Robotics

Oct 29, 2013 (3 years and 7 months ago)

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2012

Intelligent Mobile
ROBOT Navigation
Technique Using
RFID Technique

Submitted
to:


abc

[Type the author name]


Submitted

by
:

xyz

OE165

ROE1
21

[ T
Y P E T H E C O M P A N Y A D D R
E S S
]


2


*



I N D E X

*


Abstract
………………
……….
………….3


Introduction
………
………..
………………4


RFID technology
…………
……….
……….5


Using RFID for Accurate
Positioning ……….7


RFID Background


RFID Positining


Microprocessors
…………………..


Driving relays


Encoder HT 12 E


Decoder HT 12 D


RF Transmitter


RF Receiver


Atmel 89C2051 MicroController


System Architecture


RFID communication Module


FLC Navigation Module


Proposed
Navigation Algorithim


3


#

A

B

S

T

R

A

C

T


#




The mobile robot is controlled using mobile and wireless RF
communication. In this method controlling is done depending on the
feedback

provided by the sensor. This contains different modules
such as


Wireless unit module


Sensing and controlling module


When no prior knowledge of the environment is available, the problem
becomes even more challenging, since the robot has to build a
Map
of

Its S
urroundings

as it moves. These three tasks ought to be
solved
in conjunction due to their

interdependency.


In the sensing module when the
PIC micro controller is powered up
by
the high
-
speed dc motors
. The sensor is mounted on the robot.
The encoder mounted on the robot transmitting the
data continuously

And
a number of standard RFID

tags attached in robots environment
to define its path. Here the robot consists of Transmitter and
receiver. Here the
frequency used is 433 kHz.


Here we show that using RF signals from the RFID

tags as an analog
feedback signals
can be promising strategy to navigate a mobile robot
within an unknown or uncertain environment.




4

#
INTRODUCTION


#


This method is computationally simpler and more cost effective than
many of its counterparts in the state
-
of
-
the
-
art. It is also modular
and easy to implement since it is
independent of the robots
architecture

and its work space.


The main idea is to
explo
it the
ability of a mobile robot
to navigate
a priori
unknown environments
without a vision system and without building an approximate map of the
robot

workspace, as is the case in most other navigation algorithms. The
suggested algorithm is
capable of reaching a target point in its
a
priori
unknown workspace,

as well as tracking a desi
red trajectory
with a high precision
.



The proposed
algorithm

takes advantage of the emerging Radio
Frequency Identification (RFID) technology and a Fuzzy Logic

Controller (FLC) to guide the robot to navigate in its working volume.


This navigation method is based on continuous encoder readings that
provide the position, orientations and linear and
angular velocities

of
robot.


Several modules are involved in opera
ting mobile platforms, such as,
for example, the localization, navigation, obstacle avoida
nce, and path
planning modules.



The most common and popular navigation methods proposed in the
literature to date rely on dead
-
reckoning

based, landmark
-
based,
vision
-
based, and behavior
-
based techniques.




(dia : fig 1 of 65 pdf)




5

#
RFID TECHNOLOGY

#


RFID is an automatic identification method that relies on storing and
remotely retrieving data.

A
basic RFID system consists of three components:


An antenna
or coil


A transceiver (with decoder)


A transponder (RF tag) electr
onically programmed with unique
information







The
Antenna

emits radio signals to activate the tag and to read and
write to it.


The
reader
emits radio waves in ranges of anywhere from one

inch to
100 feet or more, depending upon its power output and the Radio
Frequency used. When an RFID tag passes through the
electromagnetic zone,it detects the reader’s activation signal.


The reader decodes the data encoded in the tag’s integrated circuit

(silicon chip) and the data is passed to the
host computer

for
processing

The purpose of an RFID
s
ys
tem is to enable data to be transmitted by
a portable

device, called a tag, which is read by an RFID reader and
processed according to the needs of a
particular application. The data
transmitted by the tag may provide identification or location
information, or specifics about the product tagged, such as price,
color, date of purchase, etc. RFID quickly gained attention because of
its ability to track mo
ving objects.



6















7

Using RFID for Accurate Positioning



The RFID positioning can be divided into four steps: in the first step, install RFID
tags on roads in a certain way, store very accurate location information along with
other necessary
information to the tags, add an RFID reader module to the
navigation system, and use this new location information. Apart from the RFID
system, we also propose to use a tag database. Due to the memory constraint on
the tag and the data size that needs be w
ritten in a tag, the use of a database for
tags is a necessary condition. In addition, the speed of the RFID communication
also makes the use of the tag database indispensable.



RFID BACKGROUND
:


In this section a brief overview of RFID technology in
general is given. An RFID
system consists of tags, a reader with an antenna, and software such as a driver
and middleware. The main function of the RFID system is to retrieve information
(ID) from a tag (also known as a transponder). Tags are usually affix
ed to objects
such as goods or animals so that it becomes possible to locate where the goods and
animals are without line
-
of
-
sight. A

tag can include additional information other
than the ID, which opens up opportunities to new application areas.


An RFID

reader together with an antenna reads (or interrogates) the tags. An
antenna is sometimes treated as a separate part of an RFID system. It is,
however, more appropriate to consider it as an integral feature in both readers
and tags since it is essential f
or communication between them. There are two
methods to communicate between readers and tags;
inductive coupling
and
electromagnetic waves
. In the former case, the antenna coil of the reader induces
a magnetic field in the antenna coil of the tag. The tag
then uses the induced field
energy to communicate data back to the reader. Due to this reason inductive
coupling only applies in a few tens of centimeter communication. In the latter case,
the reader radiates the energy in the form of electromagnetic waves
. Some
portion of the energy is absorbed by the tag to turn on the tag’s circuit. After the
tag wake up, some of the energy is reflected back to the reader. The reflected
energy can be modulated to transfer the data contained in the tag.


Three frequency r
anges are generally used for RFID systems: low (100~500 kHz),
intermediate (10~15 MHz), and high (850~950 MHz, 2.4~5.8 GHz). The
communication range in an RFID system is mainly determined by the output power
of the reader to communicate with the tags. The
field from an antenna extends
into the space and its strength diminishes with respect to the distance to tags.
The antenna design determines the shape of the field so that the range is also
influenced by the beam pattern between the tag and antenna. Althou
gh it is
possible to choose power levels for different applications, it is usually not allowed

8

to have complete freedom of choice due to legislative constraints on power levels
as in the case of the restrictions on carrier frequencies.




RFID POSITIONING
:

we propose to use RFID technology for positioning. This technique, however, would
not replace GPS rather it is a complementary technique. In this section, we give an
overview of the RFID positioning and describe the feasibility of the idea.


Overview


The RFID positioning can be explained as follows: First,
RFID tags need to be
installed

on a road in a manner which could
maximize the coverage and the
accuracy of positioning
. Upon installation, necessary information such as
coordinates of the location

w
here the tag is installed needs to be
written on each
tag
. The accuracy of this position information is very critical for this technique to
be successful
. The position information can be acquired by using DGPS or some
other methods, which would take much l
onger time to compute the location.

Contrary to GPS in navigation systems where real time positioning is necessary, the
time for getting the accurate information would be tolerated since this
computation would take place once
.

Vehicles, then, need to be
eq
uipped with an RFID reader

that can communicate
with the tags on a road. No matter how accurate the RFID positioning is, it only
gives the position where the tags are.

Therefore the vehicles need also to be
equipped with a GPS receiver and inertial sensors

such as a gyroscope for
positioning when there are no tags around. While driving, the vehicles constantly
monitor the presence of a tag.
On detection, the reader retrieves the information
from the tag including a lane marker.


The deployment should be don
e step by step: places such as tunnels from which
getting GPS signal is not an option should be the first, intersections the next,
urban areas, and then nationwide.



Feasibility


In this subsection, the issues of feasibility of the RFID positioning are discussed.

Contrary to the robot case, let us assume an RFID tag be installed on a road,
where the operation environment for the tag is very harsh; high temperature in
summer, low i
n winter, dusts, rain, snow, etc. Furthermore,
vehicles equipped with
an RFID reader

thatis compatible to the tags on the roads can move very fast;
some cars (Porsche) can go as

fast as 300 km/h. To be more
useful the tags should
contain the information a
bout the road property (number of lanes, which lane it is
on, how far to the nearest intersection, etc) other than the location information.

9

More data decreases the communication speed and

requires more memory,
which leads to high cost.


In summary, there
are issues to be addressed before full
-
fledged deployment of
RFID tags nationwide.



Making RFID tags that can withstand a harsh environment.



Fast communication speed between readers and tags.



The data size





Figure 1. RFID Tags on a Road


Tag Database


While there would be location information in a tag, it would be almost impossible to
embed all the necessary information in a tag due
to memory constraints and the
dynamic nature

of some information. Information such as absolute coordinates of
the locati
on will not be changed. On the contrary, relative coordinates and the
property of the road on which the tag is could change some time (unlikely, though).
Moreover, we can embed more useful information such as nearest museums,
restraints, and gas stations.


However, the contents of the information vary all the time. The

data size as well
as the dynamic nature of it prevents from writing all the information
at the
installation time. To address this issue, we
devise a tag database which stores
information cor
responding to the tags
available on the roads in a region (country
for instance). The
information stored in the tag database is whatever information
on real tags
and more such as point

of interests.

Another reason for the necessity of the tag database come
s from the
speed of
the RFID communication.

It may not be fast enough to get all the information
from a tag while driving at, for instance, 150km/h. However,
getting only
identification (ID) is very feasible even at such a high velocity.
Once the ID is
retrieved, it can be efficiently searched the tag database and extracted whatever
information necessary.



10

The tag database is a collection of tags and a part of the digital map that a
navigation system may carry. Generally, a digital map consists of cells
each of
which contains network information for route guidance. The network information is
a graph with nodes and links.


Figure 2 shows a class diagram of the digital map. In the diagram, TagDB is an
aggregation of Tag objects which represent tags in a real world. Each cell has links
to the collections of nodes, links, and tags. For simplicity, we only show the
attributes of

the Tag object. As in the diagram, a Tag object includes ID, absolute
coordinates X and Y, relative coordinates RX and RY, link ID where the tag is, and
the property field. This last field is for the number of lanes of the link, type of
the road (highway,

local, etc), and so on. In Java language and most of other
programming languages, type
long
is 8 bytes, type
float
and
int
are 4 bytes, and
type
short
is 2 bytes.




Figure 2.
Tag Database Class Diagram



The data size of a tag is 30 bytes.

Therefore eve
n with a million tags on the roads,
thereby in the database,
the size of the tag database is approximately 30MB.

Since more and more embedded devices have large flash memories and even
gigabytes of hard drives, the sheer size of the tag database would not
be a big
issue.



11


#
MICROPROCES
SORS

#



Driving Relays:

Using the outputs of the HT
-
12D or HT
-
648L decoder ICs to drive relays is quite
simple. Here are schematics showing how to drive relays directly from the data
-
output pins of the decoder.








ENCODER HT12E :

HT12E

is

an

encoder integrated circuit

of

2
12

series

of

encoders.

They

are

paired

with

2
12

series

of

decoders

for

use

in

remote

control

system

applications.

It

is

mainly

used

in

interfacing

RF

and

infrared

circuits.

The

chosen

pair

of

encoder/decoder

should

have

same

number

of

addresses

and

data

format.


Simply

put,

HT12E

converts

the

parallel

inputs

into

serial

output.

It

encodes

the

12

bit

parallel

data

into

serial

for

transmission

through

an

RF

transmitter.

These

12

bits

are

divided

into

8

address

bits

and

4

data

bits.


HT12E

has

a

transmission

enable

pin

which

is

active

low.

When

a

trigger

signal

is

received

on

TE

pin,

the

programmed

addresses/data

are

transmitted

together

with

the

header

bits

via

an

RF

or

an

infrared

transmission

me
dium.

HT12E

begins

a

4
-
word

transmission

cycle


12

upon

receipt

of

a

transmission

enable.

This

cycle

is

repeated

as

long

as

TE

is

kept

low.

As

soon

as

TE

returns

to

high,

the

encoder

output

completes

its

final

cycle

and

then

stops.




FEATURES


Operating
voltage 2.4V~12V for the HT12E


Low power and high noise immunity CMOS technology


Low standby current: 0.1_A (typ.) at VDD=5V


HT12A with a 38kHz carrier for infrared transmission medium


Minimum transmission word Four words for the HT12E


Built
-
in oscillato
r needs only 5% resistor


Data code has positive polarity


Minimal external components


HT12A/E: 18
-
pin DIP SOP package


Pin Diagram:




13

Pin Description:



Pin

No

Function

Name

1

8

bit

Address

pins

for

input

A0

2

A1

3

A2

4

A3

5

A4

6

A5

7

A6

8

A7

9

Ground

(0V)

Ground

10

4

bit

Data/Address

pins

for

input

AD0

11

AD1

12

AD2

13

AD3

14

Transmission

enable;

active

low

TE

15

Oscillator

input

Osc2

16

Oscillator

output

Osc1

17

Serial

data

output

Output

18

Supply

voltage;

5V

(2.4V
-
12V)

Vcc



BLOCK DIAGRAM




14






FLOW CHART



TIMING DIAGRAM




DECODER HT12D:


15

HT12D

is

a

decoder integrated circuit

that

belongs

to

2
12

series

of

decoders.

This

series

of

decoders

are

mainly

used

for

remote

control

system

applications,

like

burglar

alarm,

car

door

controller,

security

system

etc.

It

is

mainly

provided

to

interface

RF

and

infrared

circuits.

They

are

paired

with

2
12
series

of

encoders.

The

chosen

pair

of

encoder/decoder

should

have

same

number

of

addresses

and

data

format.


In

simple

terms,

HT12D

converts

the

serial

input

into

parallel

outputs.

It

decodes

the

serial

addresses

and

data

received

by,

say,

an

RF

receiver,

into

parallel

data

and

sends

them

to

output

data

pins.

The

serial

input

data

is

compared

with

the

local

addresses

three

times

contin
uously.

The

input

data

code

is

decoded

when

no

error

or

unmatched

codes

are

found.

A

valid

transmission

in

indicated

by

a

high

signal

at

VT

pin.


HT12D

is

capable

of

decoding

12

bits,

of

which

8

are

address

bits

and

4

are

data

bits.

The

data

on

4

bit

latch

type

output

pins

remain

unchanged

until

new

is

received.




FEATURES


Operating voltage 2.4V~12V


Low power and high noise immunity CMOS Technology


Low standby current


Capable of decoding 12 bits of information Pair with Holteks 2 Series of encoders


Received codes are checked 3 times


Address/Data number combination


HT12D: 8 address bits and 4 data bits


HT12F: 12 address bits only


Built
-
in oscillator needs only 5% resistor


Easy interface with an RF or an infrared transmission medium


Pin Diagram of HT
12D


16

Or Pdf (dia)


PIN DESCRIPTION

PORT 1



The Port 1 is an 8
-
bit bi
-
directional I/O port.



Port pins P1.2 to P1.7 provide internal pull
-
ups.



P1.0 and P1.1 require external pull
-
ups. P1.0 and P1.1 also serve as the positive input (AIN0)
and the negative inpu
t (AIN1), respectively, of the on
-
chip precision analog comparator.



The Port 1 out
-
put buffers can sink 20 mA and can drive LED displays directly.



When 1s are written to Port 1 pins, they can be used as inputs.



When pins P1.2 to P1.7 are used as inputs and

are externally pulled low, they will source
current (IIL) because of the internal pull
-
ups.



Port 1 also receives code data during Flash programming and verification.


PORT 3



Port 3 pins P3.0 to P3.5, P3.7 are seven bi
-
directional I/O pins with internal
pull
-
ups.



P3.6 is hard
-
wired as an input to the output of the on
-
chip comparator and is not
accessible as a general
-
purpose I/O pin.



The Port 3 output buffers can sink 20 mA.



When 1s are written to Port 3 pins they are pulled high by the internal pull
-
ups
and can be
used as inputs.



As inputs, Port 3 pins that are externally being pulled low will source current (IIL)
because of the pull
-
ups.



Port 3 also serves the functions of various special features of the AT89C2051 as listed
below: Port 3 also receives so
me control signals for Flash programming and verification.


RST

Reset input. All I/O pins are reset to 1s as soon as RST goes high. Holding the RST pin
high for two machine cycles while the oscillator is running resets the device. Each machine
cycle takes
12 oscillator or clock cycles.

XTAL1

Input to the inverting oscillator amplifier and input to the internal clock operating circuit.

XTAL2

Output

from
the inverting oscillator ampli
fier.


17



OSCILLATOR CHARACTERISTICS

The XTAL1 and XTAL2 are the input and ou
tput, respectively, of an inverting amplifier
which can be configured for use as an on
-
chip oscillator, as shown in Figur
e.

Either a
quartz crystal or ceramic resonator may be used.

To drive the device from an external clock source, XTAL2 should be left
unconnected
while XTAL1 is

driven as shown in Figure.

(dia)



Or


Pin

No

Function

Name

1

8

bit

Address

pins

for

input

A0

2

A1

3

A2

4

A3

5

A4

6

A5

7

A6

8

A7

9

Ground

(0V)

Ground

10

4

bit

Data/Address

pins

for

output

D0

11

D1

12

D2

13

D3

14

Serial

data

input

Input

15

Oscillator

output

Osc2

16

Oscillator

input

Osc1

17

Valid

transmission;

active

high

VT

18

Supply

voltage;

5V

(2.4V
-
12V)

Vcc





Block Diagram of HT 12D




18



19




FLOW CHART









20



TIMING DIAGRAM



Applications

of HT 12E & HT 12D:



Burglar Alarm, Smoke Alarm, Fire Alarm, Car Alarm, Security System



Garage Door and Car Door Controllers



Cordless telephone



Other Remote Control System



RF TRANSMITTER:

The RF Transmitter used is TLP434A.It has frequency range of 315 MHz to
433MHz.It operates at a voltage range of 2
-
12VDC.


(dia)



RF RECEIVER:

The RF Receiver used is RLP434A. It has frequency range of 315MHZ
to
433MHZ.it operates at a voltage range of 3.3
-
6 VDC

(dia)



21



ATMEL 89C2051

MICROCONTROLLE
R
:

The AT89C2051 is a low
-
voltage, high
-
performance CMOS 8
-
bit microcomputer
with 2K bytes of Flash programmable and erasable read
-
only memory (PEROM).
The device is
manufactured using Atmel’s high
-
density nonvolatile memory
technology and is compatible with the industry
-
standard MCS
-
51 instruction
set.

The AT89C2051 provides the following standard features:


2K bytes of Flash


128 bytes of RAM


15 I/O lines


two 16
-
bit
timer/counters


a five vector t
wo
-
level interrupt architecture


a full duplex serial port


a precision analog comparator


on
-
chip oscillator and clock cir
cuitry



In addition, the AT89C2051 is designed with static logic for operation down to
zero frequency and
supports two software selectable power saving modes.


The Idle Mode stops the CPU while allowing the RAM, timer/counters, serial
port and interrupt system to continue functioning. The power
-
down mode saves
the RAM contents but freezes the oscillator disabli
ng all other chip functions
until the next hardware reset.





PIC16F877 MICROCONTROLLER
:





22

#
SYSTEM ARCHITECTURE

#



The proposed navigation system consists of two fundamental modules:


an RFID communication module and


a Fuzzy Logic Controller (FLC)
navigation module.


The
RFID communication module

is responsible for communicating
with the
tags

(or transponders)
through an RFID reader

with two receiving antennas
mounted on the robot. A high level system configuration setup of the current
navigation te
chnique is depicted in Fig. 2, where two RFID tags,
T
1
and
T
2
, are
attached on the ceiling. The robot’s desired trajectory is the straight
-
line
segment connecting the orthogonal projection points, A and B, of tags
T
1
and
T
2
, respectively.

The
robot employs

the FLC module

in order to
provide the necessary control
action

to its actuators, which is required to move the robot from one point to
another in its workspace.


C
onsider a scenario where the robot is presented with a desired trajectory
defined by an ordered sequence of tag IDs, like
(00
,
01)
, for instance,

then it
first navigates to the orthogonal projection point of the tag with ID
00
, then it
moves along the virtual straight line linking the orthogonal projection points of
tag IDs
00
and
01
, where it will stop. The

Novelty

in this navigation scheme is that it is independent of the tag positions,
odometry information, and structure of the working environment.





23



A. RFID Communication Module

Before starting the mission, the robot sends
time multiplexed single
-
tone
sinusoida
l signals
with different

frequencies, and then
listens to the
backscattered signals
from the RFID tags. The high level architecture

of the
custom
-
designed RFID communication module is

depicted in Fig

3
.

Preliminary
studies were conducted to

confirm the fact that

using a custom
-
built RFID
reader

with two receiving antennas can determine the relative

p
osition

of the
tag (left or right) with respect to the reader mounted on the robot.


Let
φ
1
and
φ
2
be the phase angles

of the signal rec
eived by the reader’s
receiving
antennas

1 and 2, respectively.

The phase difference,
Δ
φ
, is then

defined by

Δ
φ
=
φ
1


φ
2
.


....
(1)


This phase difference is then passed to the FLC in order

to decide
on the
robot’s direction





24



B. Fuzzy

Logic Controller

The
purpose

of

FLC

is
to provide intelligent actions to be taken by the robot.
In the current work,

we use a
single
-
input single
-
output

Mamdani
-
type FLC as
shown in Fig. 4. The

aim of the FLC is to decide
on the
amount of
tune
-
up

Δ
θ
that
the robot has to apply to its current direction

θ
to converge to its target
position. The FLC’s input is

the phase difference
Δ
φ
provided by the two
directional

antennas mounted to the RFID reader on the robot. The

robot then
uses this information to updat
e its direction

following the update rule (2).


θ
(new)
=
θ
(old)

θ


……
(2)



The fuzzification and defuzzification membership functions

are taken as linear
triangular and trapezoidal membership

functions for their higher
computational
efficiency

[19], as depicted in Fig. 5. An empirical analysis

was performed to
optimize these membership function

parameters to improve the FLC’s
performance. The “min”

and “max” operators are adopted as the t
-
norm and s
-
norm

operators, while

the defuzzification method is set to be the

center of
area.



25







Three fuzzy rules are defined to reflect the fact that

the phase difference of
the signal is positive when the

transmitting transponder is on the left side of
the receiving



26

antenna and
vice versa. These rules are:

If
Δ
φ
is
Neg
Then
Δ
θ
is
CCW

If
Δ
φ
is
Zero
Then
Δ
θ
is
Zero

If
Δ
φ
is
Pos
Then
Δ
θ
is
CW

The rationale behind these rules is that the robot is supposed to turn
left/right (CCW/CW, for counter
-
clock wise and clock
-
wise, respectively) if
the RFID tag is on the left/right of the receiving antenna, where
Δ
φ
is
negative and positive, respectively.





27



#
PROPOSED NAVIGATION
ALGORITHM

#

This section explains how the modules described above

fit into the overall
navigation framework. The efficient

coordination among the RFID
communication module,

FLC, and different actuators of the robot allows it to
hav

less computational overhead while being executed on the

robot’s processor.

The following is a description of the

different steps of the algorithm.


Step 1:
The robot is pre
-
programmed with an ordered list

of tag ID numbers
defining its

desired path.


Step 2:
The target tag of the current navigation phase

is determined from the
ordered list of tags defining the

complete robot’s desired path.


Step 3:
Once the target tag is known, the robot scans

through the signals
backscattered from all the tags within

its communication range and records the
phase angles
φ
1

and
φ
2
of the signal coming from the tag representing the

target tag at that time instant.


Step 4:
The phase difference,
Δ
φ
, of the destination tag’s

signal is calculated
as defined in (1).
Δ
φ
is then

passed to

the FLC to quantize the tuneup the robot
has to apply to

its direction to better direct itself towards its destination.

The
robot updates its heading as in (2) and dispatches the

required control action
to its relevant actuators.


Step 6:
Once
the robot reaches the destination tag, it

checks for more
available destination tag IDs in the

desired path. If the current destination tag
is the last tag,

then the robot simply stops. If not, the algorithm restarts


from
Step 2
.


A thorough evaluation of
this algorithm’s performance

is provided in the
following section.





28

CONCLUSION



A novel RFID
-
based robot navigation system is proposed
in this paper. The robot is first presented with a
sequence of tag IDs defining its desired trajectory. This
sequence is

then broken into a sequence of ordered
pairs of IDs each of which represents a line segment of
the overall trajectory. The mobile robot tracks each
segment by continuously assessing the phase
difference of the RF signals at the reader’s two
receiving ante
nnas coming from the current segment’s
target tag. An FLC is adopted to compute the control
effort necessary for the robot actuators to tune its
orientation appropriately. Computer simulations were
run to demonstrate the algorithm’s efficiency in
tracking
various paths of different complexities despite
the noise in the RF feedback signal. The proposed
algorithm is very modular as it can be easily
implemented on virtually any type of robotic systems
and working environments. It is computationally
inexpensive

as it is free of any visual data processing.




With the help of sensor feedback mechanism with RF
communication the mobile robot can be controlled from
a far distance, which is desirable fact when the robot is
working in hazardous environment.





29

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