2. • Mobility is essential for quality of life which
includes self-care, work, school, play or leisure
• Powered wheel chair provides a means of
independence
• Enables the user to have control of their
environment .
• The most basic task of the motorized wheel chair
is to take input from the user, usually in the form
of a small joystick, and translate that motion into
power to the wheels to move the person in the
desired direction.
3. Motorized Wheelchair
• Motorized Wheel
Chair is a combination
of a postural support
system, a mobility
base, that are joined
to create a dynamic
seated environment
and a motor
mechanism with input
device, controller and
power supply system.
4. History
• 1950s - Everest & Jennings (USA) developed the first
powered wheelchair
• 1980s - wheelchairs now were microprocessor-
controlled and provided customization of controls
to meet the need.
• 1980-90s - the revolution in powered wheelchair
design with various new controls, styles, range in
distance, suspension, maneuverability, and seating
options developed.
5. PARTS
A powered wheelchair comprising:
• a frame having a first end and a second end.
• seat support coupled to frame between first end
and second end;
• a pair of swivel wheels coupled to frame proximate
at first end;
• a pair of motor driven wheels coupled to the frame
proximate second end;
• a pair of motors, each of motors being coupled to a
corresponding driven wheel.
• Battery coupled to the motors, the batteries
providing power to motors;
6. PARTS
• an electronic controller coupled to the motors.
• a seat assembly reversibly coupled to the seat
support and extending upwardly above the
frame.
• footplate
• A coupling mechanism associated with the frame
and the footplate, the first coupling mechanism
removable coupling the footplate to the tubing
member,
7.
8. Positive outcomes
• Increased functional ability
• Greater social inclusion
• Access to education and employment
• Reduced dependence on care givers
• Reduced fatigue
• Better performance & efficiency
9. Negative outcomes
• Access adaptations such as wheelchair spaces on
public transport and wheelchair lifts are frequently
designed around a typical manual wheelchairs
• Because of the weight and size they typically cannot
be self propelled by the user
• Require daily charging
• Generally non-foldable and requiring tie-downs in a
van for transportation
• Required more maintenance and requires specialist
for repair
• Expensive
10. Types Powered wheelchair
• Rear wheel, Mid wheel Front wheel
drive and all-wheel drive versions
• Indoor and outdoor
• Typically controlled by a joystick but
there are various other inputs
• Tilt-in-space and reclining systems
are available
11. Rear wheeldrive versions
• Traditionally, rear-wheel drive electric
wheelchairs were preferred because of
their similarity to manual wheelchairs
in design and manoeuvrability.
• The drive wheels are behind the user’s
center of gravity, and the casters are in
the front.
• It has predictable drive characteristics
and stability but can be difficult to
maneuver in tight places because of its
larger turning radius.
• Using this type of chair is similar to that
of driving a vehicle.
• For user needing speed, these types of
wheelchairs can be geared for high
speed; with maintaining stability and
control.
• The balance of the wheelchair is ideal
for outdoor surroundings.
12. Mid wheel drive wheelchairs
• Mid wheel drive wheelchairs have
gained popularity because they provide
increased maneuverability.
• The drive wheels are directly below the
user’s center of gravity.
• It has a smaller turning radius, making it
more effective for indoor mobility, but
not as good outdoors.
• This makes it easy to use and handle in
confined space like kitchens, bathroom
interior. In restrained spaces.
• Maneuverability is great with the turning
range being basically negligible since it
can turn on its own axis.
• It is much more approachable indoors
compared to a rear wheel drive chair.
13. Front Wheel Drive Wheel Chair
• The drive wheels are in front of the user’s
center of gravity, and the rear wheels are
casters.
• This setup tends to be quite stable and
provides a tight turning radius.
• However, it may have a tendency to fishtail
and be difficult to drive in a straight line,
especially when travelling fast on uneven
surfaces.
• Many front wheel drive chairs have anti
tippers that prevent the chairs from leaning
completely forward.
• Large wheels are attached ahead of seating
area which allows the chair to go over
tougher terrain 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.
14. All Wheel Drive
• It is Four wheel drive
wheelchairs.
• It can accompany
through sand, snow, mud
and over rough terrain.
• These are highly
maneuverable used as
indoor and outdoor
mobility.
15. Push-rim-activated power-assisted
wheelchairs (PAPAWs)
• Push-rim-activated power-assisted wheelchairs
(PAPAWs) incorporate features of both manual
and electric wheelchairs. A PAPAW typically
consists of an ultralight manual wheelchair with
an external power source (batteries and motors).
It complements rather than replaces an
individual’s ability to manually propel the
wheelchair. The push-rim contains sensors that
detect the direction and magnitude of force
applied to it by the individual. The motors are
then activated and assist in the propulsion of the
wheelchair.
16. Standing Power Wheelchairs
• A Standing Wheelchair assists a
wheelchairs user to elevate the
wheelchair from a seated position to
a stand-up position. These
wheelchairs allows the wheelchair
users who are usually limited to a
seating state; to stand up and stretch
out with ease and safety and enables
communication with people and
objects at eye level. These are used
to achieve both regular mobility and
to help the user to STAND UP using
either hydraulic or power source. By
keeping the body in a standing
position, the wheelchair provides
users with the ability to place
wheelchair-bound persons in a
standing position reduces muscle
contraction.
18. The input method is how the client drives and controls the
wheelchair.An input device is used by the user to specify
velocity and directional when driving or to navigate within
a menu displayed on the controller
19. Factors for Selection of Input Devices
• For selection of an appropriate input device
following factors should be taken into
consideration:
• cognitive,
• physical, and
• perceptual motor skills
20. Types of Input Devices
Various types
– Proportional (joystick).
– Non-proportional (switch inputs, sip and puff).
• Scan-control can be used to reduce the number of
switches required
21. Proportional (joystick)
• Proportional controls provide a range of
direction and speed within 360 degrees.
• The controls typically are joysticks but
can be devices such as touch pads.
• They can be placed anywhere the client
has movement within that range and
can be graded to allow for control of
direction and speed.
• Joysticks are primarily operated by the
hand but can be placed in other places,
such as under the chin, behind the
head, and under the foot. Proportional
controls require the least complicated
electronics, resulting in fewer parts to
maintain.
Chin Control
Hand Control
22. Non-Proportional
• Non-Proportional or Digital controls provide an on/off style of
control, much like a light switch.
• There is no range of speed and direction, as with a proportional
control, so the wheelchair will immediately drive exactly as
programmed.
• With digital controls, there is one switch for each direction.
• Switches can include push switches, proximity switches, and
pneumatic switches.
• Digital controls are more often driven in latched. For example, if a
client is using a sip and puff control, the command for the forward
direction is a hard puff. If the control was not latched, the client
would have to continually puff to make the chair go forward.
Forward and reverse are the only directions that can be latched.
Once latched in forward, the left and right directions remain
momentary. When a client is driving in latched, a safety ‘‘kill’’
switch must be mounted where the client can consistently access in
case of an emergency.
23. Computerized Technology
• Ambient Corporation, Japan is developed a system
called Audio which interprets electrical signals sent by
the brain to the larynx in an attempt to speak, and
translates these signals into digital speech through a
processor.
• The company integrated this system into an electric
wheelchair, except instead of having the computer
produce speech it turns the human electrical signals
into movement commands for the chair.
• This technology is performing well and has the
potential to return control to fully paralyzed
individuals.
25. Uses of Input Devices
• Driving.
• To operate powered seating functions
• To operate assistive technology devices such
as an environmental control unit.
• This requires a display box to show the client
which function he or she is in.
26. Modern power wheel Chairs now have the options
to control a PC, mobile phone or aspects of the
environment
27. • Microprocessor-based
• The controller translates signal from the input device to a
velocity and direction command for the power controller
• It provides feedback to the user via the display
• Monitors performance of wheelchair
• Contains the custom adjustable control parameters of the
chair
28. The most common controller
parameters may be adjusted for a
user:
• Max speed
• Acceleration
• Deceleration
• Turning speed,
• Turning acceleration
• Turning deceleration
29. • The battery provides the energy for the power wheelchair to
drive
• They are connected to the Power controller
• 24V (commonly 2 x 12V)
• Wet cell batteries, Lead-Acid batteries , Deep Cycle Gel Cell
batteries, or absorbent glass mat (AGM) batteries may be
used in electric wheelchairs.
• Electric wheelchair batteries are rechargeable batteries.
• Rated capacity: 20 – 120 Ah
30. Battery Type
Use of “gel-cell” batteries an
important safety issue because “gel-
cell” batteries are sealed and so no
acid will leak in the event that the
chair falls over
31. • The Power Controller sends the power to the
motors and to the other modules
• It controls the electrical energy delivered to the
motors.
• Common type is a Pulse width modulated DC to
DC converter
32. • The motors control the power
wheelchair speed and direction
• 24V AC or DC
• resistance of different motor types
varies typically between 20 and 350 mΩ
• Current rating 60 – 120 A
MOTORS
33. Brake Mechanism
• Regenerative braking mechanism used to
powered wheelchairs (standard wheelchairs)
that have been modified to assist the user by
supplying a torque to the wheels via electric
motor.
• The motor brakes engage when the user
physically slows the wheels with his/her hands to
give the user greater control. Not only does this
decrease the risk of crashing while travelling on a
decline, but it increases the life of the battery.
