05469190

8/12/2019 05469190

1/5

Proceedings of the 2010 IEEE Students' Technology Symposium

3-4 April 2010, IT aragpur

Design Of Intelligent Robotic A For Visually

Challenged'A n fr physc n

Seima Saki Sl, Sabita Devi D

C 1, Mechatronicsri Kishna Clg O Egirig And Tch.

Coaoe aseaskcemailco sabiskcetmailco

Ab- physically disabled person nourishing himself wasconsidered as a great deed in the 19th century. But this age hasbecome an era where talents are considered as the matter of fact,in spite of their physical weakness. Here is a newfangledtechnology, through which a robot imitates human handwriting

and acts as a proxy during strenuous circumstances. What therobot does is that, it acts according to the voice commandsimposed on it, thereby fullling the physical ailment of the needy.Writing is brought by feeding a particular style in the form of

images, which is stored as fonts in its memory. This not only

assists disabled persons, but also supports people who need aproxy for their hand writing. When a particular font is fed, itwrites what was dictated, thereby, acting as a human hand. This

methodology that has been proposed here is much practical andthe design shows improved eciency.

Kwdv B'

. NTRODUCTION

Scientists fed their entire lifetime in developingtechnologies that would act as a substitute to hide physicalimpaient. ast achievements infer that there were deviceswhich when coupled with a physically challenged person,would assist in erasing the traces of the abnormality. But stillthe originality of humans retains its color. No device could dothe job with so much perfection as a human does. And everyhuman, physically able or disabled, is unique. Why cant arobot imitate humans uniqueness, say, writing .. ! This paperpresents the study of robotic arm that has been committed topaper writing.

As a matter of fact, the system recognizes human language

using speech analysis techniques and the signal obtained isconverted into text. Texts are processed and converted intodigital data. These digital signals control the servos present.Servos move in accordance with the information stored in thecontroller. This movement accomplishes writing.

. FDAENTAL BUILDING BLOCKS

Our aim is to make the arm trace the letters in accordancewith the speech. A movement can be brought up withmanipulators and sero motors Since servos are fully self

Maoj SCompuer Tecnoogy

PSG Coege o Technology,Coatoe as.anoj89@galco

contained, the velocity and angle control loops are very easy toimplement, while prices remain very affordable. For this, eachalphabet, number or a special character is to be represented bya unique values, so called as onts', and fed into a memory.

And servo caies out the activity in relation to those values.And we need a microcontroller to take up memory and controlactivities. We require a speech analyzer to conver humanlanguage into text and text is processed further into digital data.Microconollers work with digital inputs. So the speech has to

be converted into digital string.

To position and orient the robotic arm, manipulators of 6-DOF or 3-F can be employed. The OF of the manipulatorare distributed into sub assemblies of a and wrist. The endeffectors which are exteal to the manipulators are attached toit to hold the pen. The proper shape and size of the gripper and

the method of holding are determined by the objects to begrasped and task to be performed. nclination angle is to be

specied to the motor, so that it writes accordingly.Given below is the outline of technical blocks of the robotic

humanoid hand.

PCH

YZR

(Se X)

SERVO MOTOR AN MAIUATOR

IHAh f

.

u

DGTZR

ONTROLER /.-I 1001010 . iFTES T E NE

QUATIONS OF A

ARATR

ARATER EQN ARESS

0000

0001

000 ,- MMORY

'

igure . asic uilding locks-Overview

THOP094 978-1-4244-5974-2/10/$26.00 2010 IEEE 49

8/12/2019 05469190

2/5

. HARDW ARE ESCRIPTIONS

A. Speech Analyses

Speech recognition (also nown as automatic speechrecognition or computer speech recognition) converts spokenwords to text. eople with disabilities can benet om speechrecognition programs. ndividuals with leaing disabilitieswho have problems with thought-to-paper commication

(essentially they think of an idea but it is processed incoectlycausing it to end up differently on paper) can benet om thistechnique.

A speech recognizer is a device that automaticallytranscribes speech into text. t can be thought of as a voiceactuated pewriter' in which a computer program carries outa transcription and the transcribed tt' appears on aworkstation display. The recognizer is usually based on somevocabulary that restricts the words that can be rinted' out.Until we state otherwise, the designation word denotes a wordform dened by its spelling. [2]

The speech signal is analyzed and the feature is extracted

for comparison with stored references in the patte matchingblock. The reference pattes which characterize individualspeech classes to be recognized are obtaned by a trainingprocedure using a large set of nown examples. A decisionscheme determines the word or class of the unknown input

based on the matching scores or evaluated similarity measres.Methods to be discussed for dealing with adverse conditionsmay take place in various blocks in the diagram. [7].

MOING

N

RNINGTH

igure 2. locks Of Speech Analyses System

B. Sero Motor

P

A servo mechanism or servo is an automatic device thatuses eor-sensing feedback to correct the perfoance of amechanism. The term correctly applies only to systems wherethe feedback or eor-corection signals help conolmechanical position or other parameters. The servomotors usesoptical encoders which are in the fo of discs, the motorrotates thrugh which the encoders acks the count. n tu thisservo is connected to MCU which executes in accordance tothe track. AC servo motors are used because of ther higheciency and con ol. They need not to be replaced oen asDC servos due to absence of brushes. Servo ulse widthmodulation (WM) is a powerful technique for controlling

THOP094


3-4 April 2010, IIT aragpur

servo with a controllers digital outputs. The general concept isto simply send an ordinary logic square wave to the servo at aspecic wave length, and the servo goes to a particul angle(or velocity if the servo is modied). The wavelength directlymaps to servo angle. n our system, the motor is driven by themicroconoller which relates input digital string with its stored2 representations of symbols. The standd time vs. angle isrepresented in this cht:

r, n -H Low e

sWKl2 m

StQ

igure 3 Angle variation of servo in relation to the width of clock

/ Sero Motor-Design:

A servo motor system, comprising a servo motor unit, aservo driver unit, power transmission lines for supplyingelectric power om servo driver unit to servo motor unit, dsignal transmission lines for supplying electric signals to servodriver unit.

a) Sero motor unit comprises:t has a servo motor; a pole sensor for detecting a magnetic

state, a rotary encoder for detecting a mechanical state of servomotor; a parallel-serial signal conversion circuit for convertingan output om pole sensor and an output om rotary encodernto a single serial signal; and a line iver for sending outserial signal through one of sgnal transmission line, a theephase AC motor, and outputs om pole sensor and rotaryencoder include u-phase, v-phase and w-phase signals fompole sensor and a Z-phase signal om rotary encoder.

b) Drier logic circuit comprising:

Thee AND circuits is connected to the input ends ofparallel-serial signal conversion circuit, u-phase, v-phaseand w-phase signals being each supplied to an input end ofassociated one of AND circuits whose other ends arecommonly connected to receive sensor output signal while Zphase signal is directly supplied to one of the inputs ofparallel-serial signal conversion circuit; and a motor logiccircuit comprising a NOR circuit is connected to the outputends of serial-parallel signal conversion circuit, detected uphase, v-phase and w-phase signals separated om serialparallel signal conversion circuit being supplied to different

50

8/12/2019 05469190

3/5

input ends of NOR circuit so as to produce an abnormalcondition detection signal om an output end of NOR circuitin case an abnormal condition is detected by abnoalcondition sensor while a detected Z-phase signal is directlyobtained om one of output ends of serial-parallel signalconversion circuit.

c) Driver logic circuit:

t comprises of an AND circuit and three OR circuits isconnected to the input ends of rst parallel-serial signalconversion circuit, u-phase signal and Z-phase signal beingsupplied to dierent input ends of AND crcuit while an outputf AND crcit and v-pha and w-phase sgna ar echsupplied to an input end of associated one of OR circuits whoseother ends are commonly connected to receive sensor outputsignal; and a motor logic circuit comprising a NOR circuit, anAND circuit and an OR circuit is connected to the output endsof said second serial-parallel signal conversion circuit, threeoutputs from second serial-parallel signal conversion circuitbeing connected to different inputs of NOR circuit as well as todierent inputs of AND circuit while an output of NOR circuitand one of output ends of second serial-parallel sialconversion circuit being connected to different inputs of ORcircuit so that a detected Z-phase signal, a detected u-phasesignal and a detected sensor output signal may be obtainedom output end of NOR circuit, and output end of OR circuitand an output end of said AND circuit, respectively, whiledetected v-phase and w-phase signals may be obtaineddirectly om associated ones of output ends of second serialparallel signal conversion circuit.

Servo driver unit comprises:

A line receiver for receiving serial signal transmitted omline driver through signal transmission line; a serial-parallelsignal conversion circuit for separating output signals om

rotary encoder and pole sensor from serial sial, and acontroller for conolling supply of electric powr to servomotor unit through power transmission lines according toseparated parallel signals.

ManipulatorsA robot is required to carry out specic task by moving its

end effectors accurately and repeatedly. The dynamic controlof manipulator motion and interaction forces requires nowledge of forces and torques that must be exerted on a manipulated joints to move the links and the end effectors om thepresent location to the desired location, with or without theconstrains of the particular planned end effectors trajectoryand planned end effector force/torque.

1) Congurations of the arm of robot:

Gantry: These robots have linear joints and aremounted overhead. They are also called Cartesianand rectilinear robots.

Cylindrical - Named for the shape of its workenvelope, cylindrical anatomy robots are fashionedom linear joints that connect to a rotary base joint.

THOP094


3-4 April 2010, IIT Kharagpur

olar - The base joint of a polar robot allows fortwisting and the joints are a combination of rotaryand linear types. The work space created by thisconguration is spherical.

Jointed-Arm - This is the most popular industrialrobotic conguration. The arm connects with a

twisting joint, and the links within it are connectedwith rotary joints. t is also called an articulated

robot.2 Degrees ofeedom:

To enance robot hand dexterity, the robot should bedesigned to have a redundant number of degrees of eedom.n redundant robotic systems, inverse kinematcs om taskdescription space to joint space becomes ill-poised, making adifcult to determine joint motions. To avoid this ill-posedness, most proposed methods introduce an additional input

term calculated from an intentionally introduced aricialindex of performance. A 4 DOF redundant handwriting robot,whose endpoint is constraind on a two dimensional plane,such as a sheet of paper, is presented here. [9]

x,y and z are the Cartesian co-ordinates, q,q2,q3 and q4

denotes vector of joint angles. L,L2,L3 and L4 i the distancebetween two vector of joint angles. [ 1].

igure 4. 4DO and Writing Robot

The schematic diagram of a manipulator control system isshown. The dotted lines for the feedback indicate that thecontrol system may or may not employ feedback of the actual

joint locations and velocities. The parameters q,q,q" ,t etc. areshown in the gure, where q gives the history of position andq,q ,t are its derivatives.

DESC'DTAS"(ORIEAON

posmN FED EFFR)

_ -igure 5. anipulator lock Diagram

ACUAL JIENtFEO

LClON.

"ELen T

51

8/12/2019 05469190

4/5

IV. ALGORITHM FOR TRACKING OF THEMANIULATOR MOVEMENT

A. FOR LINE-BRESENHAM'S LINE D WINGALGORTHM

The Breseham line algorithm is an algorithm whichdetermines which points in an n-Dimensional raster should beplotted in order to form a close approximation to a straight line

between two given points.

line(x, x, y, y)in! detax :=x I - xin! detay =y I - yreal error :=0real deltaerr := deltay / deltaxin!y :=y x x x

{plot(x,y)eor :=error + deltaerrabs(error) 0.5

{y:= y + Ierror :=error - 1.0

}}

B. FOR CIRCLE-M-POINT CIRCLE ALGORITHM

In computer graphics, the midpoint circle algorithm is analgorithm used to determine the points needed for drawing acircle. The algorithm is a variant of Bresenham's linealgorithm, and is thus sometimes nown as Bresenham's circlealgorithm, although not actually invented by Bresenham.

circle(int cx, int cy, int radius){

}

error =-radius; x =radius; y =0; (x>=y)

{plot8points(cx, cy, x, y);error +=y;++y;eror +=y;i(error>=)

{

--x;error -=x;error -=x;

}}

plot8points(int cx, int cy, int x, int y)

{plot4points(cx, cy, x, y);

THOP094

Proceedings of the 2010 IEEE Students' Technolo Symposium


(x !=y)plot4points(cx, cy, y, x);

plot4points( cx, cy, x, y)

{P(cx + x, cy + y);(x !=0) P(cx - x, cy + y);

(y !=0) P(cx + x, cy - y);(x !=0 && y !=0) P(cx - x, cy - y);

igure 6. A Sample character shown as a combintion of line andcircle

V . RESULTS AND OBSERVATION

We used Digital Differential Analyzer Algorithm atthe beginning but we did not end up with accurate results. So

we ended up using Bresehams algorithm. ositioning the write head aer horizontal retrace andvertical retrace was not precise. Rectied it aer minoradjustments with the coordinates.

65 rpm servo was found to miss match with theprocessing delays by the recognition system. Hence we endedup with 45 rpm motor.

VI. ONCLUSION

The proposed model can be eciently applied for allcategories of people, more specically physically challenged.The world itself is becoming automated and hence we areforced to go forward by leaps and bounds across the

techology to make up a better living. This tecology wouldsurely assist such escalating advancements, not only made fornormal people but also for the disabled.

EERENCES

[] R K ittal, I J Nagrath: "Robotics and control, Tata cGraw-ilPubl ications.

[2] rederick: "Stastical methods for speech recognition (chapter 1) -1997IT.

52

8/12/2019 05469190

5/5

[3] IEEE transaction on "Audio, speech and language processing, sep2006, vol. 14, issue 5.

[4] IEEE transaction on "Robotics and Automation, march 2003, vol. 10,Issue .

[5] Third Inteational conference on "Information technology andapplications 2005.Volume 2 issue 4 to 7 pages 21 to 24

[6] IEEE transaction on "Speech And Audio Processing, July 2004 Volume12, Issue 4

[7] Ravi P. Ramachandran, Richard Mammone: "Mode methods of

Speech processing, Kluwer academic publications 1995. pg no. 236

THOP094

Proceedings of the 2010 IEEE Students' Technoloy Symposium


[8] Third international conference on "Information technology andapplications, july, 2005. Vol 2, issue 4-7.

[9] IEEE joual of robotics and mechatronics: "Control of handwritingrobot with DO redundancy based on feedback in task coordinates,Vol.16 No.4, 2004.

0 www tryengineering.or

53

05469190

Documents