An electric wheelchair offer mobility and the freedom to get around. A motorized wheelchair, powerchair, electric wheelchair or electric-powered wheelchair (EPW) is a wheelchair that is propelled by means of an electric motor rather than manual power. Motorized wheelchairs are useful for those unable to propel a manual wheelchair or who may need to use a wheelchair for distances or over terrain which would be fatiguing in a manual wheelchair. They may also be used not just by people with 'traditional' mobility impairments, but also by people with cardiovascular and fatigue-based conditions.The electric-powered wheelchair was invented by George Klein who worked for the National Research Council of Canada, to assist injured veterans after World War II.[1]
2. Introduction
The first practical electric powered w/c used starter
motors and batteries from automobiles.
These early w/c provided limited mobility for some
people with upper extremity impairments.
Relays were soon used to provide greater control over
electric powered w/c.
Next the transistor provided much better control and
allowed for the development of specialized control
interface for the user.
3. Cont…
In 1980 the implementation of microprocessor and
metal oxide semiconductor field effect transistors
helped to improve reliability.
Microprocessor provided improved control and greater
stability to match the characteristics of the chair to the
abilities of the user.
6. Seating system
1. Reclining wheel chair and Powered elevating leg rest
2. Tilt in space wheel chair
3. Powered seat elevator
7. Reclining wheel chair Powered elevating leg
rest
Reclining wheelchairs
allow the w/c user to
change the sitting posture
through the use of a
single interface i.e
switch.
Assist in pressure relief
and Pressure
redistribution
8. Tilt in space wheel chair
Fixed seat to back support
angle
Fixed seat to lower leg support
angle
Fixed lower leg to foot support
angle
User can independently adjust
the seat tilt with switch access.
9. Powered seat elevator
This features allows the seat to
be raised or lowered to
accommodate for the height
differences
Improve reach
Improve social interaction
Chair is slowed for the safety
concearn
10. Electronic
Electronics vary with each powered w/c
The controller is the part of the wheelchair that acts as
the brain
Dictates the driving characteristics of wheelchair and
what type of input devices will be used.
The client activates input devices such as joystick
Joystick operates the controller and controller operates
the motor which drive the wheelchair
It can be programmable
11. Input method
Drive input
Proportional control
Digital control
Mode of operation-
Momentary
Latched
12. Cont…
Drive control mechanism:-
1. Hand control
2. Pneumatic sip-puff / breath control system
3. Chin drive
4. Head control
5. Tongue control
14. Sip and puff/breath control system
Used primarily by people with
tetraplegia who do not have functional
use of their arms and hands.
This system used with breath control
A sip and puff access device consists of a
replaceable straw located near the mouth.
The w/c is controlled by a sequence of
pulling pushing air through the straw with
the mouth
Generally the user will sip a specific
number of time to indicate a direction and
puff to confirm the choice and activate
the movement of the w/c
15. Chin drive
No use of their extremity but have
good neck musculature
Accomplished either positioning
proportional joysticks at the chin or
mouth
By using speciality control with either
latched or momentary input
16. Head controls
Another alternative to using a
standard joystick
Good head control
Types of head control-
1. Sensor or magnetic fields which
are interrupted by head motion
2. Proportinal/RIM
3. Microswitch control
17. Tongue control
Sensor packed dental retainer
SCI pt can manipulate with
their tongue to manuever a
w/c.
18. Scanning array system
Available only one switch placement site
A light scans around a display highlighting different
directions
When the lights hits the direction of travel, activation of
switch moves the chair in that direction
19. Single Switch system
Person is unable to use head array system or sip-puff
system
Single switch can be set up at any area with minimal
active movement to control the wheelchair
21. PAPAW
uses a hybrid power source drawn
from human energy provided by the
user and electromechanical power
provided by a battery source and
electric motors.
control system uses a form of
shared control, commonly referred
to as gain-scheduling among control
systems engineers.
22. CONT…
The torque applied to the pushrim
by the occupant is amplified,
whether proportionally or through
the use of a formula or rule
structure.
The maximum speed with
assistance is limited to avoid
attaining uncontrollable or
potentially hazardous speeds.
braking is assisted in order to
control the rate of deceleration
23. Power stand up
Allows a person to come to
standing who ordinarily
would be unable to stand
without support
Accessed through switches
24. Stair climbing wheel chair
Stair climbing w/c can be
classified as multipurpose
or single purpose
Stair climbing w/c can be
grouped in to three broad
categories.
1. Assistant operated
2. Jointly operated and
3. Independently operated
27. References
Rory A. Cooper, Rosemarie Cooper, Michelle Tolerico, Songfeng
Guo, Dan Ding,and Jonathon Pearlman , Advances in Electric-
Powered Wheelchairs, Top Spinal Cord Inj Rehabil 2006;11(4):15–
29
Susan B.O.Sullivan, The prescriptive wheelchair, Physical
rehabilitation, 6th edition, 2014
John d hsu, john w michael, John r Fisk, wheelchair mobility for
disabled childern and adults, AAOS Atlas of orthoses and assistive
devices, 4th edition.
John d hsu, positioning and wheeled mobility for children and
adults with disablities, Atlas of orthoses and assistive devices,, 3rd
edition,
tongue Drive uses dental retainer and tongue piercing to control
wheelchair (Wired UK).html