2. OBJECTIVE
THIS PAPER PROJECTS AN ANDROID BASED SMART AUTOMATED
WHEEL CHAIR FOR HANDICAPPED /ELDERLY PEOPLE TO HELP
THEM. THIS WHEEL CHAIR IS BATTERY POWERED CONTROLLING
TWO D.C. MOTORS. THE CHAIR FUNCTIONS ON THE
ACCELEROMETER SENSOR IN BUILT IN MODERN DAY SMART-
PHONES. TILT OF THE SMARTPHONE IS GIVEN AS AN INPUT
COMMAND TO THE MICROCONTROLLER VIA BLUETOOTH MODULE
THE MOVEMENT OF THE D.C. MOTORS. DEPENDING ON THE
DIRECTION OF TILT OF THE SMART PHONE, THE
MICROCONTROLLER CONTROLS THE WHEELCHAIR DIRECTIONS.
ALSO AN I.R. DETECTION SYSTEM IS UPGRADED TO DETECT THE
OBSTACLE ON THE PATH OF WHEEL CHAIR AND MAKE OBJECT
COLLISION MORE AVOIDABLE. THUS MAKING HANDICAPPED
3. PROBLEM
DEFINITION
1) WHEEL CHAIR STABILITY IS AN ISSUE IN MOTORISED
WHEELCHAIRS . THIS ISSUE CREATES A PROBLEM IN HANDLING?
2) AUTOMATIC BRAKING SYSTEM WHICH IS USED FOR STOPPING
AND CONTROLLING THE WHEELCHAIR IS MISSING FROM MANY
PRESENT DAY WHEELCHAIR?
3) COST EFFECTIVE WHEELCHAIR IS AN ISSUE?
4) CHARGING THE BATTERY AFTER IT GETS DISCHARGED IS AN
ISSUE?
4. LITERARY SURVEY
IN THE PAPER ON “VOICE OPERATED WHEEL CHAIR” VOICE COMMAND INPUT
IS TAKEN FROM ANDROID MOBILE AND CONVERTED INTO TEXT AND THIS
TEXT IS GIVEN TO THE MICROCONTROLLER VIA BLUETOOTH MODULE TO
CONTROL THE OPERATION OF D.C. MOTORS.
IN THE PAPER “VOICE AND TOUCH SCREEN BASED AND SPEED CONTROL OF
WHEEL CHAIR FOR PHYSICALLY CHALLENGED USING ” INPUT TO IN TWO
WAYS I.E. VIA VOICE COMMAND OR TOUCH COMMAND I.E. HM 2007 IS USED
AS A VOICE RECOGNITION DEVICE. INPUT METHOD IS SWITCHED THROUGH
SWITCHES AND INPUT IS GIVEN BY ANY TWO METHODS . TWO D.C. MOTORS
ARE USED TO PROVIDE MOTION.
IN THE PAPER “A WHEEL CHAIR STEERED THROUGH VOICE COMMANDS AND
ASSISTED BY A REACTIVE FUZZY-LOGIC CONTROLLER”, VOICE COMMAND
CONTROLLED AND A FUZZY LOGIC CONTROLLER IS USED ALONG WITH A
SENSOR NETWORK TO AVOID COLLISION OF THE WHEEL CHAIR. FUZZY
LOGIC CONTROLLER IS USED TO RECTIFY PROBLEM CAUSED DUE TO LOW
5. INTRODUCTION
• This is an android based automated wheelchair that can be used by
differently abled.
• It uses android based smartphones which have inbuilt axis
accelerometer sensors and bluetooth wireless technology.
• The proposed concept exploits these features of the smart phones to
use at as a transmitter and control device.
7. • Often accelerometers is used to present landscape or portrait views of
the devices screen based on the way the device is being held.
• Bluetooth - Bluetooth present in the smartphone can be tapped using
protocol stacks in the app design environment of the mobile operating
system.
• Functional app-this app interfaces accelerometer to work with
Bluetooth module. E.g. bluetooth pro(by develectronicx)
8. RECEIVING SECTION
• Microcontroller-its need involves the reception of data signals that are
transmitted by the smartphone via Bluetooth module and control the
working of servo and DC motors.
• The wheelchair interacts with the smartphone app by means of this
Atmega 16 microprocessor via Bluetooth. –
9. MOTION DRIVER COMPONENTS
• DC motor- directional motor in wheelchair is provided by this motor (left-
right).
• For higher weights we need DC motors of high torque.
• The DC is connected to the axle of the rear wheel and is connected to a
battery through a motor driver which is being signaled by the controller.
• DC motor- for driving linear motion the type of motor generally used is a DC
motor with the higher RPM, torque.
• It is connected to the rear wheels of the wheelchairs.
15. MECHANICAL STRUCTURES &
DIMENSIONS
THE FOLLOWING FIGURE ILLUSTRATES THE IMPORTANT WHEELCHAIR
TERMINOLOGIES THAT NEEDS TO BE CONSIDERED WHILE DESIGNING A
WHEELCHAIR.
16. PERSONS WITH DISABILITIES ACT (1995) RECOGNISES THE RIGHTS OF
INDIANS WITH DISABILITIES AND CREATES OPPORTUNITIES FOR EQUAL
PARTICIPATION IN ALL GOVT. RUN INFRASTRUCTURES AND SERVICES.
THERE ARE CERTAIN STANDARDS AND GUIDELINES THAT ARE PROVIDED
REGARDING THE DIMENSIONAL SPECIFICATIONS OF A WHEELCHAIR BY
GOVERNMENT AGENCIES LIKE BUREAU OF INDIAN STANDARDS (BIS),
CENTRAL PUBLIC WORKS DEPARTMENT (CPWD), OFFICE OF CHIEF
COMMISSIONER FOR PERSONS WITH DISABILITIES (CCD) ETC. BASED ON
EXTENSIVE SURVEY AND RESEARCH ON THE POPULATION OF PEOPLE
WITH DISABILITIES WHO USE WHEELCHAIRS.
THE ACT DOES NOT COMMENT ON THESE DIFFERENT STANDARDS AND
GUIDELINES AND DOES NOT ENDORSE ANY ONE OF THEM. SO WE’RE JUST
GOING TO GO WITH BUREAU OF INDIAN STANDARDS’ RECOMMENDATIONS.
17. FIXED STANDARD
ACCORDING TO BIS (IS 7454 AND IS 4963) :
(ALL MEASUREMENTS ARE IN MILLIMETRES)
UNOCCUPIED WIDTH = 650-720
UNOCCUPIED LENGTH = 1000-1100
HANDLE HEIGHT = 910-950
ARMREST HEIGHT = 700-740
SEAT HEIGHT = 480-510
COMBINED KNEE + TOE CLEARANCE DEPTH = 400-450
18. CHOSEN STANDARD
FOR THE SCALED DOWN MODEL, THE DIMENSIONS WHICH WILL BE USED
ARE AS FOLLOWS:
UNOCCUPIED WIDTH = 325
UNOCCUPIED LENGTH = 500
HANDLE HEIGHT = 455
ARMREST HEIGHT = 350
SEAT HEIGHT = 240
COMBINED KNEE + TOE CLEARANCE DEPTH = 200
THE BASE PLATE LENGTH = UNOCCUPIED LENGTH - (COMBINED KNEE +
TOE CLEARANCE DEPTH ) = 500 - 200 = 300
19. DESIGN &
MANUVERABILITY
THE LOCATION OF THE DRIVE WHEELS (THE WHEELS POWERED BY
THE MOTOR) IN THE REAR, MIDDLE OR FRONT OF THE CHAIR HAS A
DEFINITE EFFECT ON THE CHAIR’S PERFORMANCE IN DIFFERENT
ENVIRONMENTS.
MANEUVERABILITY
THE POSITION OF THE DRIVE WHEELS SIGNIFICANTLY AFFECTS
THE SPACE NEEDED FOR THE CHAIR TO TURN AROUND, AND THE
WAY THE CHAIR MANEUVERS IN TIGHT SPACES.
MID-WHEEL AND FRONT-WHEEL DRIVES ARE LESS SENSITIVE TO
PROBLEMS CAUSED BY WEIGHT DISTRIBUTION THAN REAR-WHEEL
DRIVES.
20. MANUVERABILITY
MID-WHEEL DRIVES ARE THE MOST MANEUVERABLE BECAUSE THEY HAVE THE SMALLEST
360-DEGREE TURNING CIRCUMFERENCE AND THE TIGHTEST TURNING RADIUS (20 TO 26
INCHES), MAKING THEM EXCELLENT INDOOR CHAIRS.
FRONT-WHEEL DRIVES HAVE A TURNING RADIUS OF 25 TO 28 INCHES AND A LARGER 360-
DEGREE CIRCUMFERENCE THAN MID-WHEEL DRIVES. HOWEVER, THEY ACTUALLY NAVIGATE
AROUND TIGHT CORNERS BETTER THAN THE OTHER TWO DRIVE SYSTEMS BECAUSE THE
POSITION OF THE PIVOT POINT GIVES THEM A VERY SHORT FRONT END. BUT TURNING
AROUND IN A SMALL SPACE IS TRICKY BECAUSE OF THE LONG BACK END.
REAR-WHEEL DRIVES HAVE THE LARGEST 360-DEGREE CIRCUMFERENCE AND TURNING
RADIUS (30 TO 33 INCHES) OF THE THREE DRIVE SYSTEMS, MAKING THEM MORE DIFFICULT
TO MANEUVER IN TIGHT SPACES.
IN ADDITION, THE FOOTRESTS ON A REAR-WHEEL DRIVE CHAIR TAKE UP MORE SPACE
BECAUSE THEY’RE TYPICALLY ANGLED FORWARD AT ANYWHERE FROM 80 TO 60 DEGREES
IN ORDER TO CLEAR THE LARGER FRONT CASTERS.
ON FRONT-WHEEL DRIVE CHAIRS, THERE ARE NO FRONT CASTERS TO INTERFERE WITH
HAVING 90-DEGREE FOOTRESTS. WHEN THE FOOTRESTS ARE COUNTED IN THE TURNING
RADIUS MEASUREMENT, THEY ADD LESS THAN AN INCH.
21. HANDLING OBSTACLES &
INCLINES
FRONT-WHEEL DRIVES ARE OPTIMAL FOR TRAVERSING OBSTACLES
SUCH AS CURBS, GRASS, GRAVEL, UNEVEN TERRAIN AND SNOW. THIS
IS BECAUSE THE 14-INCH DRIVE WHEELS ARE THE FIRST WHEELS TO
ENCOUNTER OBSTACLES AND THEY PULL THE REST OF THE
WHEELCHAIR OVER THEM.
A REAR-WHEEL DRIVE MEANS THE DRIVE WHEELS ARE PUSHING THE
FRONT CASTERS OVER OBSTACLES. BECAUSE PUSHING IS HARDER
THAN PULLING, REAR-WHEEL DRIVES AREN’T QUITE AS EFFICIENT
GOING OVER OBSTACLES AS FRONT-WHEEL DRIVES.
22. CASTER STEM DESIGN
CASTER STEMS MUST BE KEPT AS VERTICAL AS POSSIBLE. CASTER STEMS
THAT ARE NOT VERTICAL CAUSE A NUMBER OF PROBLEMS. IF THE STEM
LEANS FORWARDS AT THE TOP THE CHAIR IS DIFFICULT TO TURN AND THE
KNEES ARE LOWER WHEELING FORWARDS THAN WHEN WHEELING
BACKWARDS. IF THE STEM IS LEANING BACKWARDS AT THE TOP, THE CHAIR IS
DIFFICULT TO KEEP IN A STRAIGHT LINE AND THE KNEES RAISE UP HIGHER
WHEN ROLLING FORWARDS. ALSO WHENEVER THE WHEELER STOPS THE
CHAIR WILL ROLL BACKWARDS A LITTLE.
23. ANALYSIS
WHEEL CHAIR
TYPES
TURNING
RADIUS(Inches)
Mid wheel drive
Wheel chair
20-26
Front wheel drive
Wheel chair
25-28
Rear wheel drive
Wheel chair
30-33
WHEEL CHAIR
TYPES
Step, bump or
curb that is up
to 2 inches
Step, bump or
curb that is up
to 2.5 inches
Step, bump or
curb that is up
to 3.2 inches
Step, bump or
curb that is up
to 3.3 inches
and high
Mid wheel drive
Wheel chair
Yes Yes No No
Front wheel
drive
Wheel chair
Yes Yes Yes Yes
Rear wheel
drive
Wheel chair
Yes No No No
24. WHEEL CHAIR TYPES Stability on straight path Stability on inclined path
Mid wheel drive
Wheel chair
equal more
Front wheel drive
Wheel chair
equal moderate
Rear wheel drive
Wheel chair
equal least
WHEEL CHAIR
TYPES
Front position Mid position End position
Front wheel drive
Wheel chair
Less stable stable stable
Mid wheel drive
Wheel chair
- - -
Rear wheel drive
Wheel chair
stable stable Less stable
Stability due to battery allocation on an inclined plane:
26. ADVANTAGES
• Less expensive then the conventional automatic wheel chairs.
• Obstacle detection using IR sensors.
• Front wheel drive provides high maneuverability
• Straight stem in caster help aids in smooth operation.
27. DISADVANTAGES
• Requires smartphone for operation as a accelerometer is the main
device over which the main system is dependent.
• Battery recharging is needed so smartphone battery and battery to
drive the motor have to periodically recharge and maintained.
28. SOLUTIONS TO
PROBLEMS
1.) THE VERTICAL CASTER STEM OF THE FREEWHEELS IN THE REAR END REDUCE THE STABILITY
RELATED ISSUES OF THE WHEELCHAIR .
2) CONTROLLING ISSUE IS HANDELED THROUGH THE USE OF I.R. SENSORS WHICH IMPROVE
CONTROL AND HANDLING.
3) MANUVERABILITY AND HANDLING OF THE WHEELCHAIR SYSTEM IS IMPROVED BY CHOOSING
THE FRONT WHEEL AS MOTOR DRIVES.
4) REDUCED COST OF THE WHEELCHAIR AS ONLY BLUETOOTH IS USED FOR COMMUNICATING
BETWEEN THE DEVICES RATHER THAN A VIRTUAL CIRCUIT. THUS THE COST OF ADDITIONAL
ELECTRICAL CIRCUITORY AND MECHANICAL GEAR ASSEMBLY IS REDUCED.
5) TWO 12 VOLTS 3.5 AMP BATTERIES WERE USED INSTEAD OF DIRECT CURRENT SUPPLY BUT
DUE TO OVERCHARGING OF THE BATTERIES THE CIRCUITS WERE BURNT AS THE DISCHARGING
RATE OF THE BATTERIES WERE 4.5 AMP AND THIS LED TO FAILURE . THEREFORE USE OF 12 VOLTS
, 3.5 AMP DC BATTERIES IS RESTRICTED UNTIL THE PROBLEM OF OVERCHARGING IS SOLVED.
29. IMPROVEMENTS AND MODIFICATION
• Can also alarm the user about the obstacle.
• Improvements can be made by using various hand gestures of the user.
• Battery can be recharged by alternator.
• Automatic balancing of sitting area can be provided using secondary
accelerometer in case of bumps and curbs.
• Movements can be controlled and location of wheelchair can be tracked
using server connection.
• Eyes movement based automated wheelchair.
30. REFERENCES
• Based on the research paper “Smartphone Accelerometer Controlled
Automated Wheelchair” by Vigneshwar. Santhanam and Vignesh. Viswanathan.
• http://psrcentre.org/images/extraimages/ICECEBE%20113824.pdf
• Wikipedia - Smartphone, http://en.wikipedia.org/wiki/Smartphone
• www.parth-shah.org
• mirley.firlej.org
• junweihuang.info
• nextsepian.com
