Upload
others
View
1
Download
0
Embed Size (px)
Citation preview
DESIGN AND FABRICATION OF ELECTRIC WHEELCHAIR AND MODIFICATION OF
SUITABLE TWO WHEELER FOR PARAPLEGICS
PRASANT PARAMATMUNI
NETTUR TECHNICAL TRAINING FOUNDATION, BANGALORE, INDIA
ABSTRACT
Over 90% of paraplegics in India come from the low income or lower middle
class income group. Since there is no social security system in India and the
Government Medical institutions cannot keep patients with spinal injuries in the
hospital for any length of time, they are sent home after the intital treatment.
Electric wheelchairs would have helped them be more independent and help
them function as an integral part of society. This project involved developing a
low cost electric wheelchair which is capable of withstanding the rigors of the
road and modifying a two wheeler available in the market so that the electric
wheelchair will be integral part of the two wheeler enabling the paraplegic person
to ride the road. The Project involved making an electric wheelchair which
combines as an intergral part of a two wheeler so that he/she can just attach
his/her wheechair to the road going vehicle without getting off of his wheelchair.
Thus making him completely independent of any external help. Hence the project
involved the deisgn of the electric wheelchair having constraints on basis of size
of the kinetic Honda withoug major component modification of the kinetic. The
wheelchair also has to be guided into the kinetic and then locked in position so
that it will be an intergral part of it. The project focused on lowering cost for the
fabrication part so that if it is manufatured on a large scale, the overall price of
the entire unit will be low enabling those physically handicapped people who are
cash strapped to purchase the unit.
INTRODUCTION
DISABILITY is the term which is in use from many
decades now. As per Oxford Etymology, “DISABILITY”
is used in many contexts viz, it was a sport in 1650’s
with the name “CAP IN HAND”, it was used in horse
races in 1750’s, in 1870’s it is “Any race or competition
in which the chances of the competitors are sought to
be equalized by giving an advantage to the less
efficient or imposing a disadvantage upon the more
efficient.” Finally, the first use of handicap to designate
mental or physical impairment is recorded in a 1915
photo caption: The Handicapped Child. From 1915 the
word “DISABILITY/HANDICAP” has become the brand name for the people who
are physically or mentally challenged.
“Disabilities is an umbrella term, covering impairments, activity limitations, and
participation restrictions. An impairment is a problem in body function or
structure; an activity limitation is a difficulty encountered by an individual in
executing a task or action; while a participation restriction is a problem
experienced by an individual in involvement in life situations. Thus disability is a
complex phenomenon, reflecting an interaction between features of a person’s
body and features of the society in which he or she lives”
—World Health Organization
TYPES OF DISABILITIES:
Disability is caused by impairments to various subsystems of the body - these
can be broadly sorted into the following categories.
1. Physical Disability
2. Sensory Disability
a. Visual Impairment
b. Hearing Impairment
c. Olfactory and gustatory Impairment
d. Somatosensory Impairment
e. Balance Disorder
3. Intellectual Disability
4. Mental health and emotional disabilities
5. Developmental Disability
6. Nonvisible Disability
Physical Disability
Sensory Disability
PURPOSE OF THE STUDY:
People who are affected by paraplegia, accidents, muscular dystrophy and
genetic defects from loss of sensory function of the lower extremities.
According to survey conducted by NDTV there are about 17 million
physically handicapped people in India.
A survey conducted by OXFAM trust, the Indian arm of OXFAM
international says that most of the disabled people in India live below the
poverty line or are part of the lower middle class of society.
Over 90% of paraplegics in India come from the low income or lower
middle class income group. Since there is no social security system in
India and the Government Medical institutions cannot keep patients with
spinal injuries in the hospital for any length of time, they are sent home
after initial treatment. These paraplegics, left to fend for themselves,
develop bed sores and ultimately die in the prime of their youth.
Electric wheelchairs are not currently being manufactured or marketed in
India.
The only electric wheelchairs available in India are imported from
countries like UK, China etc.
Cost is one of the major factors which deter people from purchasing these
wheelchairs as they sell for a premium of 1.3-1.8 lacks for the basic
versions.
These wheelchairs have been designed to be driven on flat surfaces
unlike most of the surfaces in India.
OBJECTIVE: (PROBLEM DEFINITION & SCOPE)
1. This project aims at developing a low cost electric wheelchair which
is capable of withstanding the rigors of the road and modifying a two wheeler
available in the market so that electric wheelchair will be an integral part of
the two wheeler enabling the paraplegic person to ride on the road.
2. The Project involves making an electric wheelchair which combines
an integral part of a two wheeler so that he can just attach his wheelchair to
the road going vehicle without getting off of his wheelchair. Thus making him
completely independent of any external help. The project will be focused on
lowering cost for fabrication part so that if it is manufactured on a large scale,
the overall price of the entire unit will be low enabling those physically
handicapped people who are cash strapped to purchase the unit .
UNDERSTANDING PARAPLEGIA
Paraplegia:
When a person suffers a spinal cord injury, information traveling along the spinal
nerves below the level of injury, will be either completely or partially cur off from
the brain, resulting in Quadriplegia (Tetraplegia) or Paraplegia.
The body will still be trying to send messages
from below the level of injury to the brain known
as sensory messages, and the brain will still be
trying to send messages downwards to the
muscles in the body, known as motor messages.
These messages however will be blocked by the
damage in the spinal cord at the level of injury.
Nerves joining the spinal cord above the level of
injury will be unaffected and continue to work as
normal.
Paraplegia is when the level of injury occurs
below the first thoracic of leg movement, to
complete paralysis of the legs and abdomen up to the nipple line. Paraplegia is
an impairment in motor and/or sensory function of the lower extremities. It is
usually the result of spinal cord injury or a congenital condition such as spina
bifida which affects the neural elements of the spinal canal. The area of the
spinal canal which is affected in paraplegia is either the thoracic, lumbar or sacral
regions. Paraplegics have full use of their arm and hands.
Causes:The cause range from trauma (actual spinal cord injury: transaction or
compression of the cord, usually by bone fragments from vertebral fractures) to
tumors (chronic compression of the cord), myelitis transversa and multiple
sclerosis.
Peripheral nervous system:
Rarer is the type which is caused by damage to the nerves supplying the legs.
This form of damage is not usually symmetrical and would not cause paraplegia,
but polyneuropathy may cause paraplegia if motor fibers are affected. While in
theory the arms should also be affected, the fibers that supply the legs are longer
and hence more vulnerable to damage.
Complications:
Due to decreased movement and loss of the ability to run, paraplegia may cause
numerous medical complications, many of which can be prevented with vigilant
self care. These include pressure sores (decubitus), thrombosis and pneumonia.
Physiotherapy and various assistive technologies, such as standing frame, may
aid in preventing these complications.
Problems faced by paraplegics:
People with paraplegia encounter many challenges in their everyday lives.
Primarily, mobility problems cause them difficulties in engaging in gainful
employment or going to school. These problems also restrict their participation in
the community.
Mobility & Movement
Full head and neck movement with normal muscle strength. Normal shoulder
movement. Full use of arms, wrists and fingers.
Complete paralysis of lower body and legs. Upper body strength will vary
depending on level of injury, but the lower level, the stronger the upper body
strength and balance.
A T4 cord injured person will have good strength in the chest muscles; however
this will get progressively weaker the higher up the injury.
Sympathetic nervous system may be compromised, possibility of Autonomic
Dysreflexia.
May use an electric wheelchair for long distance independent travel or uneven
outdoor surfaces. A manual wheelchair may be used for everyday living, with the
ability to go over uneven ground for short distances.
Ability to transfer independently from bed to chair, and chair to car. Car transfers
may need assistance depending on upper body strength.
Ability to drive a car adapted with hand controls. Assistance may be required to
load wheelchair into car.
Ability to feed self independently during mealtimes.
Respiratory System
Ability to breathe normal, although respiration capacity and endurance may be
compromised.
Personal Care
Should be independent in personal care as long as no other factors are involved,
i.e., additional injuries, severe spasticity etc.
Domestic Care
Partial domestic assistance is required, such as heavy household cleaning and
home maintenance.
Ability to prepare complex meals and general household duties independently.
Communication
Normal communication skills apply.
CURRENTLY AVAILABLE DESIGNS OF WHEELCHAIRS AND THREE WHEELERS FOR
PARAPLEGICS
INTRODUCTION TO WHEELCHAIRS:
As wheelchair is a wheeled mobility device in
which the user sits. The devise is propelled either
manually (by turning the wheels by the hand) or via various automated systems.
Wheelchairs are used by people for whom walking is difficult or impossible due to
illness (mental or physical), injury or disability. People with both sitting and
walking disability often need to use a wheelbench. The earliest record of the
wheelchair in England dates from the 1670s [Oxford English Dictionary, (2 nd Ed.),
1989, Vol. XX., p.203], and in continental Europe this technology dates back to
the German Renaissance.
TYPES OF WHEELCHAIRS:
A basic standard manual wheelchair incorporates a sear and back, two small
front (caster) wheels and two large wheels, one on each side and a foot rest.
Wheelchairs are often variations on this basic design, but there are many types
of wheelchairs, and they are often highly customized for the individual user’s
needs. The sear size (width and depth), sear-to-floor height, footrests/leg rests,
front caster outriggers, adjustable backrests, controls and many other features
can be customized on, or added to , many basic models, while some users, often
those with specialized needs, may have wheelchairs custom-built.
Various optional accessories are available, such as anti-tip bars or wheels, safety
belts, adjustable backrests, tilt and/or recline features, extra support for limbs or
neck, mounts or carrying devices for crutches, walkers or oxygen tanks, drink
holders, and clothing protectors.
MANUAL WHEELCHAIRS
MANUAL TRANSIT WHEELCHAIRS
ELECTRIC WHEELCHAIRS
STAND-UPBARIATRIC WHEECHAIRSPORTS WHEECHAIR
Advantages and Disadvantages of Current Design of Wheelchairs
Manual wheelchairs do in fact have benefits over their electric counterparts that
one may not imagine. They are lightweight whereas the electric ones are heavy.
This may be a significant selling point for those people who lack body strength
necessary for some chairs. They are simpler to maneuver and even thought the
electric power chairs can move by themselves there is the chance that perhaps
the battery may die. One of the major advantages of the manual chair is that it
can go virtually anywhere. A person in the wheelchair should not be concerned
with whether the terrain is uneven or bumpy as they would if they had a power
chair.
The major disadvantage of the manual
wheelchairs is person have to do with ones
upper body. Although the exercise may be
good for the people who push themselves
over a period of time the same motion
continually can eventually bead to injury.
Another disadvantage of a manual chair is
that the tires will need to be inflated
BEACH WHEECHAIRELECTRIC SCOOTER
regularly. A variety of factors much be properly considered prior to a person
choosing between a power chair and a manual version. The manual chairs may
not come with all the fancy accessories that the power wheelchairs tend to offer
for the handicapped individuals however they can be cheaper and a bit more
efficient than their bulky power chairs alternatives.
Trikes and Tricycles for Paraplegics
CONCEPTUALIZATION:
BASIC ARCHITECTURE
CONCEPT 1CONCEPT 2
CONCEPT 3
CONCEPT 4
CONCEPT 4a CONCEPT 4b
ERGONOMIC DETAILS We know that Ergonomics (or human factors) is the scientific discipline
concerned with the understanding of interactions among humans and other
elements of a system, and the profession that applies theory, principles, data and
methods to design in order to optimize human well-being and overall system
performance.
As our study is focused on handling of elderly people & patients in
hospitals during shifting from one mobility aid (wheelchair, stretcher)to another,
we considered Ergonomics involved &Indian Public Health Standards for design
of proposed concept.
As per Indian Public Standards every Hospital should have Barrier free
access environment for easy access to non-ambulant (Wheelchair, stretcher),
semi ambulant visually disabled & elderly persons as per Govt. of India
guidelines.
Below fig. shows Anthropometric data of wheelchair user related to uses within
easy reach.
ANTHROPOMETRY DATAHuman dimensions are considered for both male and female and 95 percentile
for stature, maximum body breadth relaxed,
Hip95th percentile
406 mm (combined)
Maximum body breadth relaxed
95th percentile619 mm (combined)
Stature95th percentile
1771 mm (combined)
DETAIL DESIGN:
Major parts of the wheelchair:
Frame: The final frame design is as shown above
Hob motor: Hob motors have been used to run the electric wheelchair due to
its compactness and efficiency
Suspension system of the wheelchair: The seat of the wheelchair consists
of two parts namely
Seat lower base
Seat back rest
Front wheel: The front wheel of the wheelchair is basically the wheel
assembly of the kids cycle
Electrical circuit: The electrical circuit consists of the motor, the controller
and the switch to change the motor phase between forward and reverse.
CONCEPT 4c
PROTO TYPE:
CONCEPT 4d
CONCLUSION:
A novel approach has been made by designing and fabricating an electric wheelchair that also can be used in conjunction with a kinetic Honda. This design helps paraplegics who have motor disabilities to move easily and function as an integral part of the society.
Regular wheelchairs and three wheelers are separate units and can never be used in conjunction. The three wheelers available in the market currently come at high cost and they are restricted to outdoor use.
The cost of the wheelchair is also significantly lower than any electric wheelchairs currently available in the market. The low cost helps paraplegics who are a part of the lower class of society to function better as it does not only help in moving indoors but also on the road.
REFERENCES:
Spinal Cord Injury; Available from: www.apparelyzed.com, August 2007 Details about Hub Motors; Available from: www.goldenmotor.com, August 2007 K Mahadevan and K Balaveera Reddy, , “Design data hand books” Dr. S. Ray, “Disabled Persons in India",