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Advancement in Powered
Wheelchair technology

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.

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.

Powered wheelchair
 Base of the chair
 Seating system features
 The electronics
 Input method

Bases
 Rear wheel drive
 Centre wheel drive
 Front wheel drive

Seating system
1. Reclining wheel chair and Powered elevating leg rest
2. Tilt in space wheel chair
3. Powered seat elevator

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

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.

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

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

Input method
 Drive input
 Proportional control
 Digital control
 Mode of operation-
 Momentary
 Latched

Cont…
 Drive control mechanism:-
1. Hand control
2. Pneumatic sip-puff / breath control system
3. Chin drive
4. Head control
5. Tongue control

Hand control
 Proportional drive system
 Used with someone who has
some upper extremity muscle
control

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

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

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

Tongue control
 Sensor packed dental retainer
 SCI pt can manipulate with
their tongue to manuever a
w/c.

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

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

Other control system
 Proximity switches
 Zero touch switches
 Infrared switches

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.

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

Power stand up
 Allows a person to come to
standing who ordinarily
would be unable to stand
without support
 Accessed through switches

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

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

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