.

Chapter 1

Introduction
In recent years, the concept of applying behavior-based intelligent robots to service tasks
[Gomi,92} has been discussed. With the accelerated rate of aging of the population being
reported in many post-industrial countries, demand for more robotic assistive systems for
people with physical ailments or loss of mental control is expected to increase. This is a
seemingly major application area of service robots in the near future. For the past six years,
we have been developing a range of autonomousmobile robots and their software using the
behavior-based approach [Brooks,86] [Maes, 92]. In our experience the behavior-based
approach [Brooks, 86] [Brooks, 91a][Steels, 93] [Pfeifer & Scheier, 96] [Maes, 92] allows
developers to generate robot motions which are more appropriate for use in assistive
technology than traditional Cartesian intelligent robotic approaches [Gomi, 96a]. In Cartesian
robotics, on which most conventional approaches to intelligent robotics are based,
"recognition" of the environment, followed by planning for the generation of motion
sequence and calculation of kinematics and dynamics for each planned motion, occupy the
center of both theoretical interest and practice. By adopting a behavior-based approach
wheelchairs can be built
which can operate daily in complex real-world environments with increased performance in
efficiency, safety, and flexibility, and greatly reduced computational requirements. In
addition, improvements in the robustness and graceful degradation characteristics are
expected from this approach.
In the summer of 1995, an autonomy management system for a commercially available
Canadian-made power wheelchair was successfully designed and implemented by our
development team. The system looks after both longitudinal (forward and backward) and
angular (left and right) movements of the chair. In addition, we implemented on-board
capability to carry out "recognition"
of the environment followed by limited vocal interactions with the user. The results were
exhibited in August 1995 at the Intelligent Wheelchair Event organized by David Miller at
the International Joint Conference on Artificial Intelligence (IJCAI’95) held in Montreal.
Despite a very short development period (33 days), the chair performed remarkably well at
the exhibition.

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Encouraged by the initial success, we developed a three year plan to build a highly
autonomous power wheelchair for use by people with various types and degrees of handicap.
The intelligent wheelchair project, now called the TAO Project, intends to establish a
methodology to design, implement, and test an effective add-on autonomy management
system for use in conjunction with most common commercially available power wheelchairs.
In order to demonstrate the principle, the project will build, during its life, an autonomy
management system for several well-established electric wheelchair models currently
available on the market throughout North America and Japan.

In late 1995, a sister R&D company was established in Japan exclusively for the
development of intelligent robotic technologies for the disabled and the aged. With the
initiative of this new R&D group, the development of TAO-2 autonomous wheelchair using a
commercially available Japanese wheelchair began in the spring of 1996. Based on our
experience, methods used and some issues related to the application of the behavior-based
approach to realize an intelligent wheelchair and possibly other assistive technologies are
discussed. A brief survey is also presented of other groups who are working in this area.
1.2.Wheel chair:
A wheelchair is a chair fitted with wheels. The device comes in variations allowing
either manual propulsion by the seated occupant turning the rear wheels by hand, or electric
propulsion by motors. There are often handles behind the seat to allow it to be pushed by
another person. Wheelchairs are used by people for whom walking is difficult or impossible
due to illness, injury, or disability. People who have difficulty sitting and walking often make
use of a wheel bench.

Fig 1.1 Wheel chair

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1.2.1.Types:
A basic manual wheelchair incorporates a seat, foot rests and four wheels: two, caster
wheels at the front and two large wheels at the back. The two larger wheels in the back
usually have handrims; two metal or plastic circles approximately 3/4" thick. The handrims
have a diameter normally only slightly smaller than the wheels they are attached to. Most
wheelchairs have two push handles at the top of the back to allow for manual propulsion by a
second person.

Other varieties of wheelchair are often variations on this basic design, but can be highly
customised for the user's needs. Such customisations may encompass the seat dimensions,
height, seat angle (also called seat dump or squeeze), footrests, leg rests,
front caster outriggers, adjustable backrests and controls.

Everyday manual wheelchairs come in two major designs—folding or rigid. The rigid chairs,
which are increasingly preferred by active users, have permanently welded joints and many
fewer moving parts. This reduces the energy required to push the chair by eliminating many
points where the chair would flex as it moves. Welding the joints also reduces the overall
weight of the chair. Rigid chairs typically feature instant-release rear wheels and backrests
that fold down flat, allowing the user to dismantle the chair quickly for storage in a car.

Fig 1.2 types of wheel chair

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Many rigid models are now made with ultralight materials such as aircraft aluminum and
titanium. One major manufacturer, Tilted, builds only ultralights. Another innovation in rigid
chair design is the installation of polymer shock absorbers, such as Frog Legs, which cushion
the bumps over which the chair rolls. These shock absorbers may be added to the front
wheels or to the rear wheels, or both. Rigid chairs also have the option for their rear wheels to
have a camber. Wheels can have a camber, or tilt, which angles the tops of the wheels in
toward the chair. This allows for better propulsion by the user which is desired by long-term
users. Sport wheelchairs have large camber angles to improve stability.

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.

Transport wheelchairs are usually light, folding chairs with four small wheels. These
chairs are designed to be pushed by a caregiver to provide mobility for patients outside the
home or more common medical settings.

Experiments have also been made with unusual variant wheels, like
the omniwheel or the mecanum wheel. These allow for a broader spectrum of
movement.

The electric wheelchair shown on the right is fitted with Mecanum

wheels (sometimes known as Ilon wheels) which give it complete freedom of movement. It
can be driven forwards, backwards, sideways, and diagonally, and also turned round on the
spot or turned around while moving, all operated from a simple joystick

1.2.2.Manually propelled

Manual wheelchairs are those that require human power to move them. Many
manual wheelchairs can be folded for storage or placement into a vehicle, although modern
wheelchairs are just as likely to be rigid framed.

Manual or self-propelled wheelchairs are propelled by the occupant, usually by turning the
large rear wheels, from 20-24 inches (51–61 cm)in average diameter, and resembling bicycle
wheels. The user moves the chair by pushing on the handrims, which are made of circular
tubing attached to the outside of the large wheels. The hand rims have a diameter that is
slightly less than that of the rear wheels. Skilled users can control speed and turning and often

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learn to balance the chair on its rear wheels — do a wheelie. The wheelie is not just for
show — a rider who can control the chair in this manner can climb and descend curbs and
move over small obstacles.

Fig 1.2.2 large rear wheel chair

Wheelchair fitted with Meconium wheels, taken at an exhibition in the early

Foot propulsion of the wheelchair by the occupant is also common for patients who have
limited hand movement capabilities or simply do not wish to use their hands for propulsion.
Foot propulsion also allows patients to exercise their legs to increase blood flow and limit
further disability.

One-arm drive enables a user to guide and propel a wheelchair from one side. Two
handrims, one smaller than the other, are located on one side of the chair, left or right. On
most models the outer, or smaller rim, is connected to the opposite wheel by a folding axle.
When both handrims are grasped together, the chair may be propelled forward or backward in
a straight line. When either handrim is moved independently, the chair will turn left or right
in response to the handrim used. Some chairs are also configured to allow the occupant to
propel using one or both feet instead of using the rims

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1.3stretcher:

Fig 1.3 Stretcher

A stretcher, litter, or pram is an apparatus used for moving patients who require medical care.
A basic type (cot or litter) must be carried by two or more people. A wheeled stretcher
(known as a gurney, trolley, bed or cart) is often equipped with variable height frames,
wheels, tracks, or skids. In American English, a wheeled stretcher is referred to as a gurney.
The name comes from a horse-drawn cab patented in the USA by J. Theodore Gurney in
1883 which bore a similarity to early wheeled stretchers.[citation needed]
Stretchers are primarily used in acute out-of-hospital care situations by emergency medical
services, military, and search and rescue personnel. They are also used to hold prisoners
during lethal injections in the United States

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1.3.1. Classification

fig 1.3.1 Classification

A simple stretcher used by U.S. Marines in a training environment in December 2003. U.S.
Marines transport a non-ambulatory patient via litter, outside ofFallujah, Iraq in 2006EMS
stretchers used in ambulances have wheels that makes transportation over pavement easier,
and have a lock inside the ambulance and seatbelts to secure the patient during transport. An
integral lug on the gurney locks into a sprung latch within the ambulance in order to prevent
movement during transport. Modern stretchers may also have battery-powered hydraulics to
raise and collapse the legs automatically. This eases the workload on EMS personnel, who
are statistically at high risk of back injury from repetitive raising and lowering of patients.
Specialized bariatric stretchers are also available, which feature a wider frame and higher
weight capacity for heavier patients. Stretchers are usually covered with a disposable sheet or
wrapping, and are cleaned after each patient to prevent the spread of infection. Shelves,
hooks and poles for medical equipment and intravenous medication are also frequently
included.
Standard gurneys have several adjustments. The bed can be raised or lowered to
facilitate patient transfer. The head of the gurney can be raised so that the patient is in a
sitting position (especially important for those in respiratory distress) or lowered flat in order
to perform CPR, or for patients with suspected spinal injury who must be transported on
a long spine board. The feet can be raised to what is called the Trendelenburg position,
indicated for patients in shock. Some manufacturers have begun to offer hybrid devices that
combine the functionality of a stretcher, a recliner chair, and a treatment or procedural table
into one device
1.3.2.Basic stretchers:

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Simple stretchers are the most rudimentary type. They are lightweight and portable,
made of canvas or other synthetic material suspended between two poles or tubular aluminum
frame. Many are stored as disaster supplies and are often former military equipment.
The folding stretcher, also known as a top deck or collapsible stretcher, is similar in
design to the simple stretcher, but features one or more hinged points of articulation to allow
the stretcher to be collapsed into a more compact form for easier handling or storage. Some
models may even allow the patient to sit upright in a Fowler's or Semi-Fowler's position.
The scoop stretcher is used for lifting patients, for instance from the ground onto an
ambulance stretcher or long board. The two ends of the stretcher can be detached from each
other, splitting the stretcher into two longitudinal halves. To load a patient, one or both ends
of the stretcher are detached, the halves placed under the patient from either side and fastened
back together. With obese patients, the possibility exists of accidentally pinching the patient's
back when closing the stretcher, so care must be made not to injure them when carrying out
this procedure.
The Stokes basket, also known as litter or rescue basket, is designed to be used
where there are obstacles to movement or other hazards: for example, in confined spaces, on
slopes, in wooded terrain. Typically it is shaped to accommodate an adult in a face up
position and it is used in search and rescue operations. The person is strapped into the basket,
making safe evacuation possible. The litter has raised sides and often includes a removable
head/torso cover for patient protection. After the person is secured in the litter, the litter may
be wheeled, carried by hand, mounted on an ATV, towed behind skis, snowmobile, or horse,
lifted or lowered on high angle ropes, or hoisted by helicopter.
A reeves stretcher, reeves sleeve, SKED, or 'flexible stretcher' is a flexible stretcher
that is often supported longitudinally by wooden or plastic planks. It is a kind of tarpaulin
with handles. It is primarily used to move a patient through confined spaces (e.g. a narrow
hallway), or to lift obese patients (reeves stretchers have 6 handholds, allowing multiple
rescuers to assist extrication).
The WauK board is also designed for use in small spaces. The patient is secured to the
board with straps. It has two wheels and a foldable footrest at one end, allowing the stretcher
to be moved by one person. It can also be used at a variety of angles, making it easier to
traverse obstacles such as tight stairwells. [4]

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1.3.4.Wheeled stretchers:
For ambulances, a collapsible wheeled stretcher, or gurney, is a type of stretcher on
a variable-height wheeled frame. Normally, an integral lug on the gurney locks into a
sprung latch within the ambulance in order to prevent movement during transport. It is
usually covered with a disposable sheet and cleaned after each patient in order to prevent the
spread of infection. Its key value is to facilitate moving the patient and sheet onto a fixed bed
or table on arrival at the emergency room. Both types may have straps to secure the patient.

1.3.5.Other types of stretchers

The Nimier stretcher (brancard Nimier) was a type of stretcher used by the French
army during World War I. The casualty was placed on his back, but in a "seated position",
(that is, the thighs were perpendicular to the abdomen). Thus, the stretcher was shorter and
could turn in the trenches. This type of stretcher is rarely seen today

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Chapter-2
Literature review

2. Brief survey of the field

Below is a description of research on intelligent wheelchairs that has been conducted
and still ongoing at some institutions. The survey is not intended to be complete but to
provide an idea of the different approaches used.
2.1 IBM T.J. Watson Research Center:
Some of the earliest work in the development of intelligent wheelchairs was a system
implemented by Connell and Viola, [Connell & Viola, 90] in which a chair is mounted on top
of a robot to make it mobile. Mr. Ed, as the chair was called, could be controlled by the user
using a joystick mounted on the arm of the chair and connected to the robot. The user could
also delegate control to the system itself to perform certain functions such as avoid obstacles
or follow other moving objects. In addition to the joystick, input to the robot comes from
bumper switches at the front and rear of the robot, eight infrared proximity sensors for local
navigation and two sonar sensors at the front of the robot for following objects. Control is
passed from the user to the robot through a series of toggle switches. A set of layered
behaviors were used to control the chair’s movement. These were broken into competencies
with each small set of rules becoming a toolbox to achieve a particular goal. These groups
could be enabled or disabled by means of switches controlled by the operator. It worked as a
partnership in which the machine took care of the routine work and the user decided what
needed to be done.

2.2 KISS Institute for Practical Robotics

The KISS Institute for Practical Robotics (KIPR), located in Virginia is a non-profit
educational corporation performing R&D on the integration of robotics in assistive
technology, space robotics and autonomous underwater vehicles as
well as education in robotics and related fields. David Miller and Marc Slack at
KISS Institute have developed TinMan I and II. In TinMan II , a supplementary

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wheelchair controller is installed between the joystick and the standard wheelchair motor
controller. Along with sensors installed on the chair, the chair avoids obstacles and goes
through openings with minimum input from the user. It has been tested with two power
wheelchairs, Dynamics and Penny & Giles.

2.3 CALL Centre, University of Edinburgh:

CALL Centre at the University of Edinburgh has developed the CALL Centre Smart
Wheelchair. It was originally developed as a motivating educational and therapeutic resource
for severely disabled children. The chairs were designed to assist in the assessment and
development of physical, cognitive, social and communicative skills. Thirteen chairs have
been built and evaluated in three local school, one in a residential hospital and three others in
pre-vocational establishments. The chairs are adapted, computer-controlled power
wheelchairs which can be driven by a number of methods such as switches, joysticks, laptop
computers, and voice-output. The mechanical, electronic and software design are modular to
simplify the addition of new functions, reduce the cost of individualized systems and create a
modeless system. Since there are no modes and behaviors are combined transparent to the
user, an explicit subsystem called the Observer was set up to report to the user what the
system is doing. The Observer responds and reports its perceptions to the user via a speech
synthesizer or input device. The software runs on multiple 80C552 processors
communicating via an I2C serial link monitoring the sensors and user commands. Objects or
groups of objects form modules which encapsulate specific functional tasks. It is multitasking
with each object defined as a separate task. The architecture of behaviors each performing a
specific functional task is similar to Brooks’ Subsumption Architecture.

2.4 University of Michigan:

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Fig 2.4 PRE-WHEEL

Simon Levine, Director of Physical Rehabilitation at the University of Michigan Hospital
began development of NavChair in 1991 with a grant for a three year project from the
Veteran’s Administration [Bell et al, 94]. The Vector Field Histogram (VFH) method was
previously developed for avoiding obstacles in autonomous robots and was ported to the
wheelchair. However, this method was designed for fully autonomous robots and it was soon
determined that there were
sufficient differences in the power base between robots and wheelchairs and in the
requirements of human-machine systems that significant modifications were required. This
resulted in a new method, called Minimum VFH (MVFH) which gives greater and more
variable control to the user in manipulating the power wheelchair. The NavChair has a
control system designed to avoid obstacles, follow walls, and travel safely in cluttered
environments. It is equipped with twelve ultrasonic sensors and an on-board computer. This
team uses a shared-control system in which the user plans the route, does some navigation
and indicates direction and speed of travel. The system does automatic wall following and
overrides unsafe maneuvers with autonomous obstacle avoidance. Since it is desirable that
the system change the user’s commands as little as possible, the system and user
must cooperat ively adapt to environmental or function conditions. A new method called "
Stimulus Response Modelling" has been developed in which the system qualitatively
monitors changes in the user’s behavior and adapts in realtime. It is designed so that the
adaptation is smooth and the change in modes intuitive to the user. By adjusting the degree of
autonomy of obstacle avoidance the control modes of NavChair can be changed giving the

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user more or less control depending on the situation.

2.5 Nagasaki University and Ube Technical College:

Existing ceiling lights in an indoor environment are used as landmarks for self-
localization of a motorized wheelchair by [Wang et al, 97]. The chair is therefore restricted to
use within one building, the layout of which is known in
advance. An azimuth sensor is used to give the angle between a fixed point and a particular
object and a vision sensor detects the ceiling lights. The ceiling lights are used as the
landmarks but if the lights are missed then the azimuth sensor and the rotating angle of both
wheels provide the information necessary to continue the navigation. A laser range finder is
used to detect obstacles in the chair’s path. Two CCD cameras are used, one is used to detect
the ceiling light landmarks and the other is used in conjunction with the laser range finder to
detect objects. A slit-ray is emitted from the laser emitter and this is detected by the CCD
camera. The image signal is processed by a logic circuit constructed with an FPGA which
informs the controller if passage is clear or where obstacles exist. In twenty test runs in a
room with ten ceiling lights the maximum position error was 0.35 meters and the maximum
orientation error was 17 degrees.

2.6 TIDE Programme:

Technology initiative for disabled and elderly people (TIDE) programme of the
European Union began in 1991 as a pilot action with 21 development projects and a budget of
ECU18 million. The SENARIO project (SENsor Aided intelligent wheelchair navigatIOn),
one of the initial projects
within TIDE, includes 6 member companies from Greece, Germany, the UK, and France to
introduce intelligence to the navigation system of powered wheelchairs.
The system consists of five subsystems: risk avoidance, sensoring, positioning, control panel,
and power control. The risk avoidance subsystem includes the central intelligence and inputs
information from the sensoring and positioning subsystems. The sensoring subsystem
includes ultrasonic, odometer, and inclinometer sensors. The positioning subsystem identifies
the initial position of the chair by means of a laser range finder and allows the chair to be
used in known
environments. The control panel subsystem accepts user’s instructions and the power control

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subsystem converts the system’s instructions into vehicle movements. The system has two
modes of operation, the Teach mode and Run mode. In the Teach mode the user selects the
desired paths from a topological diagram. In the Run mode (on a predefined path) the user
selects a path and the system will follow it based on stored information obtained during the
Teach mode. On a free route, the system takes instructions from the user and navigates
semiautonomously while monitoring safety and taking action or warning the user of the level
of risk.

2.7 Wellesley College, MIT:

Wheelesley is the name given to the chair used for experimental development by Holly
Yanco, first at Wellesley College and now at MIT [Yanco et al, 95]. This chair has a
Subsumption Architecture-like layered approach to its performance. By means of a graphical
interface the user of the chair points to the direction in which the chair should head. The chair
then goes in that direction while performing other tasks such as obstacle avoidance. The
interface also allows the user to tell the chair when specific tasks such as going up a ramp are
required and to have a record of
a particular environment and important features of that environment. The chair is designed in
such a way that it can turn in place. It has 12 proximity sensors, 6 ultrasonic range sensors, 2
shaft encoders and a front bumper with sensors. A 68332 computer is onboard and the
interface runs on aMacintosh Powerbook. Work is underway to incorporate information from
the angle of the eyes of the user to control the computer as a replacement for the mouse.

2.8 Northeastern University

The long-term goal of Crisman and Cleary [Crisman & Cleary,96] is to

develop a robot which can go to a destination, retrieve an object and return it to
the operator. A teleoperated and autonomous approach each has its strength and
weaknesses. Therefore, a shared control approach is suggested to divide the task

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between the user and the robot, taking advantage of the strengths of each. The
user performs high-level functions such as object recognition and route planning
while
the robot performs safety and motion controls. Since the user points the objects
out explicitly in a video image, the robot has been named "Deictic". The robot,
after receiving instructions how to move relative to the object, performs the local motion and
waits for further instruction. This means there is continuous interaction between the user and
the robot with the user giving instructions to the robot every minute or so. Commands are
given to the robot by means of a button interface in which a verb description describes the
desired motion of the robot and a noun describes the object relative to which the motion
should be performed. The robot is
able to navigate in almost any situation using its vision system to identify corners, edges, and
polygonal patches. The initial work was done in simulation followed by an implementation
on an Invacare Arrow wheelchair. Motion controller cards, optical encoders, and a vision
system were added to the wheelchair. New directional ultrasonic transducers were developed
to detect obstacles at a wide angle in one direction and at a narrow angle in the opposite
direction. This gave the robot the ability to detect objects not at standard height. A bumper
with piezo-electric film embedded was installed to detect when the chair did bump an
obstacle. A Puma 200 was used for the reaching experiments.

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Chapter-3

3.Components used for fabrication:

3.1.Dc motor:
A DC motor is any of a class of electrical machines that converts direct current
electrical power into mechanical power. The most common types rely on the forces produced
by magnetic fields. Nearly all types of DC motors have some internal mechanism, either
electromechanical or electronic, to periodically change the direction of current flow in part of
the motor. Most types produce rotary motion; a linear motor directly produces force and
motion in a straight line.
DC motors were the first type widely used, since they could be powered from existing
direct-current lighting power distribution systems. A DC motor's speed can be controlled over
a wide range, using either a variable supply voltage or by changing the strength of current in
its field windings. Small DC motors are used in tools, toys, and appliances. The universal
motor can operate on direct current but is a lightweight motor used for portable power tools
and appliances. Larger DC motors are used in propulsion of electric vehicles, elevator and
hoists, or in drives for steel rolling mills. The advent of power electronics has made
replacement of DC motors with motors possible in many applications

Figure 3.1 DC MOTOR

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Item name Separated horsepower motor

Model YD-026
Power 600W
Apply to Low power, high performance, mechanical and electrical integration of
permanent
magnet DC, high insulation level
Apply to General industrial machinery and demestic appliance, such as
blower,
medical apparatus and instruments, electrocar, printing machine, twirl
machine
NM ≥5.5n.m
MOQ 20 Piece
Semple time 3 days
Delivery time 10 Working days after payment
Payment Terms L/C, T/T, Western Union
OME Yes

3.2.Automotive battery

Fig 3.2 battery

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An automotive battery is a type of rechargeable battery that supplies electric energy to

an automobile. An automotive SLI battery (starting, lighting, ignition) is an automotive
battery that powers the starter motor, the lights, and the ignition system of a vehicle's engine,
mainly in combustion vehicles.

Automotive SLI batteries are usually lead-acid type, and are made of six galvanic
cells connected in series to provide a nominally 12-volt system. Each cell provides 2.1 volts
for a total of 12.6 volts at full charge. Heavy vehicles, such as highway trucks or tractors,
often equipped with diesel engines, may have two batteries in series for a 24-volt system or
may have series-parallel groups of batteries supplying 24V.

Lead-acid batteries are made up of plates of lead and separate plates of lead dioxide,
which are submerged into an electrolyte solution of about 38% sulfuric acid and
62% water. This causes a chemical reaction that releases electrons, allowing them to flow
through conductors to produce electricity. As the battery discharges, the acid of the
electrolyte reacts with the materials of the plates, changing their surface to lead sulfate. When
the battery is recharged, the chemical reaction is reversed: the lead sulfate reforms into lead
dioxide and lead with the sulfate returning to the electrolyte solution restoring the
electrolyte specific gravity. With the plates restored to their original condition, the process
may now be repeated. Battery recycling of automotive batteries reduces the need for
resources required for manufacture of new batteries, diverts toxic lead from landfills, and
prevents risk of improper disposal.

3.3 Bearing:

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Fig 3.3 bearing

A bearing is a machine element that constrains relative motion to only the desired
motion, and reduces friction between moving parts. The design of the bearing may, for
example, provide for free linear movement of the moving part or for free rotation around a
fixed axis; or, it may prevent a motion by controlling the vectors of normal forces that bear
on the moving parts. Many bearings also facilitate the desired motion as much as possible,
such as by minimizing friction. Bearings are classified broadly according to the type of
operation, the motions allowed, or to the directions of the loads (forces) applied to the parts.
The term "bearing" is derived from the verb "to bear"; a bearing being a machine element that
allows one part to bear (i.e., to support) another. The simplest bearings are bearing surfaces,
cut or formed into a part, with varying degrees of control over the form, size, roughness and
location of the surface. Other bearings are separate devices installed into a machine or
machine part. The most sophisticated bearings for the most demanding applications are
very precisedevices; their manufacture requires some of the highest standards of current
technology.

3.4.Switch:
In electrical engineering, a switch is an electrical component that can break
an electrical circuit, interrupting the current or diverting it from one conductor to
another. The mechanism of a switch may be operated directly by a human operator to control
a circuit (for example, a light switch or a keyboard button), may be operated by a moving
object such as a door-operated switch, or may be operated by some sensing element for
pressure, temperature or flow. A relay is a switch that is operated by electricity. Switches are
made to handle a wide range of voltages and currents; very large switches may be used to
isolate high-voltage circuits in electrical substations.

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Fig 3.4 switch

3.5.Wheel:
A wheel is a circular component that is intended to rotate on an axle bearing. The
wheel is one of the main components of the wheel and axle which is one of the six simple
machines. Wheels, in conjunction with axles, allow heavy objects to be moved easily
facilitating movement or transportation while supporting a load, or performing labor in
machines. Wheels are also used for other purposes, such as a ship's wheel, steering
wheel, potter's wheel andflywheel.
Common examples are found in transport applications. A wheel greatly
reduces friction by facilitating motion by rolling together with the use of axles. In order for
wheels to rotate, a moment needs to be applied to the wheel about its axis, either by way of
gravity, or by the application of another external force ortorque.

3.6.MS pipe:
MS Pipe and MS Tube refers to Mild Steel Pipe or a Mild Steel Tubes Mild Steel
(MS) pipes are manufactured using low carbon (less than 0.25%) steel. Due to low carbon
content the pipes do not harden and are easy to use. As MS Pipes are made from mild steel
they can easily be welded and formed in various shapes and sizes for pipelining and tubing
purposes. These are generally used for drinking water supply i.e. Plumbing, Firefighting,
HVAC but can also be used in various other Industrial and Engineering applications. These
pipes are usually coated with other metals/paints/varnish etc to prevent it from rusting but
extra care should be taken to prevent it under extreme conditions.

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Fig 3.6 Steel pipe

3.7.Standing frame

A standing frame (also known as a stand, stander, standing technology, standing

aid, standing device, standing box, tilt table) is assistive technology that can be used by a
person who relies on a wheelchair for mobility. A standing frame provides alternative
positioning to sitting in a wheelchair by supporting the person in the standing position.

3.8 Types and function

Common types of standers include: sit to stand, prone, supine, upright, multi-positioning
standers, and standing wheelchairs. Long leg braces are also a standing device but not used
often today.

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Chapter - 4

Design developments
4.1 Specifications List
The customer’s needs were translated into engineering specifications using a method called
“Quality
Function Deployment” (See Appendix A). The list of specifications is provided below.
Table 1. Specifications List

Geometry Width: : Seat width 45.7cm (18in.) +

Length: armrest + tires
Height: : Must be about same size as
current set up
Front Wheel: : Less than 1.1 m (3.6 ft)
Connection: Space Requirement: Must be
able to fit into trunk of midsized
car
16 inches (40.6cm) as standard
tires
Rear Wheel: 24-28 inches
(70cm bicycle standard)
Minimal changes to the
wheelchair for connection
Connecting and releasing
without any further tools

Driving Behavior Handling: Sporty but still comfortable and

Traction assured: suited to daily use
Traction limited: Must maintain traction while
Control: accelerating, turning, up 20%
Should be limited traction on
snow and ice

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Must not be limited by: bevel

surfaces, curves, small steer
angle, directional stability
should be assured by mechanism
Kinematics Direction of motion: Translation in x,y,z
Rotation around z
Rotation around y should be
limited to stop roll over
Translation motion: Forward motion only, no reverse
Velocities: Regular: 5-7 km/h (3.1mph)
Accelerations: Maximum: 25 km/h (15.5mph)
Acceleration: 2 m/s2 (6.56 ft/s2)
Braking: 10 m/s2 (32.8 ft/s2)
Stresses Drive train: Average torque: 10 Nm (7.38 ft
lbf)
Maximum torque: 50 Nm (36.9
Stress type: ft lbf)
Average power: 120 W
Rotation speeds: Maximum power: 500 W
Part load of about 80 - 90%
Load distribution: Peak load 10 -20 %
Dynamic loads Continuous crank speed: 20 - 40
Force transmission: rpm
Peak crank speed: 150 rpm
If possible more forces on the
front axis
: Shocks caused by pavement

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Ergonomics Access of controls: Brake must be easy and quick to

use
Best if working without
removing hands from cranks
Gearshift should be easy and
Kind of usage quick to use
Light should be turned on by
one switch
Crank attachment: : Usually manual control,
exceptions may be tachometer
Must not interfere with user
while in use
Must not obstruct view
Maintenance General: Maintenance Break: Visual inspection and
free for 2000 hours change if ware if too large
Lubrication: Bearing Gearboxes closed and oil
lubricated for lifetime lubricated no need for
maintenance
Chains and open parts
cleaning and re lube if
necessary
Standards e Standards : ADA, ASME, DIN, EN, ISO
standards as applicablTUV and
DIN standards for Germany Use
health insurance company rules
for taking over costs

Recycling Steel: Material recycling Aluminum; Material recycling

like any other product like any other product
Rubber and Plastics: Lubricants: Disposal as
Probably thermal hazardous substances
utilization

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Steel: Material recycling Aluminum; Material recycling

like any other product like any other product

4.2.Methodology:
The following methodology is being adopted to carry out the above mentioned objectives:
1. The ansys achieved by aircraft landing gear and CAD model was designed by CATIA V5
2. Using ANSYS the overall structural load are computed and tried to validate with classical
theory.
3. Using these equivalent properties of the composite the natural frequency computations are
done.
Fig.4.1 shows present methodology.

Fig 4.2 flow chart of present methodolgy

4.2.1 Introduction to catia

CATIA which stands for computer aided three dimensional interactive applications is the
most powerful and widely used CAD (computer aided design) software of its kind in the
world. CATIA is owned/developed by Dassault system of France and until 2010, was

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marketed worldwide by IBM.

The Following general methodologies and best practices can be followed in the modeling of
components in CATIA. The Below methodologies and Best practices followed will help in
capturing the design intent of the Feature that is to be Modeled and will make the design
robust and easy to navigate through.
Specification tree structuring
Renaming appropriate features & bodies in specification tree
Handling input data & foreign bodies
Dimensioning & constraining in sketches
Parameters and relations.

4.2.2. Specification tree structuring

The SPECIFICATION TREE is the place where the histories of the features modeled are
captured. So it is highly important to have an organized tree structure which gives ease for
navigation of the features when any modification takes place. The SPECIFICATION TREE
in a structured manner. The Machining Body features are grouped under one body and base
block features in another and so on with appropriate feature operations. It is also important in
structuring the reference and construction element in the tree in an orderly manner. The
points that would be often used (like the Global Origin Point 0, 0, 0,) can be created under
Points GEOMETRICAL SET and any reference planes defining legal limits can be created in
the planes GEOMETRICAL SET.

4.2.4. Renaming appropriate features & bodies in specification tree

The renaming of features within the design becomes mandatory as it will be useful for the
end users to by far identify things for modification. For instance an end user who wants to
identify the M5 holes on the model the SPECIFICATION TREE helps easily in identifying
the M5 holes in the model there by making modifications easy. Also renaming all the features
every now and then as it is created will easy things at the end. “Base Block Sketch” and
“Base Block” is which will be useful in identifying them at a later stage. Renaming the
Bodies also helps in navigation.

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4.2.5 Handling input data and foreign bodies

Any external data that are to be handled in the model can be grouped under a
GEOMETRICAL SET called input data which can be used in the model when situation
demands.Some foreign elements like planes, points, curves and surfaces that would be used
in the modeling process. By grouping the foreign elements in a separate GEOMETRICAL
SET it is easy to identify them in the SPECIFICATION TREE.

4.2.6 Dimensioning and constraining in sketches

Planes should be intersected in the sketches and made as construction elements and
should be used as dimension reference for geometries, this helps in identifying the dimension
line clearly in a complex sketch. Equivalent dimension should be used wherever possible to
minimize modification time in the sketches. Usage of sketch analysis command is mandatory
at the end of every sketch build which helps in diagnosing the sketch thereby identifying
abnormalities. Robust design Intent can be Achieved with the Integration of Parameters and
Relations

Cad model:
Assembly view:

Fig 4.3 assembly view

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Top view:

Fig 4.4 To

Chapter 5
part description
Motor

Fig 5.1
Principles of operation
In any electric motor, operation is based on simple electromagnetism. A current-

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carrying conductor generates a magnetic field; when this is then placed in an external
magnetic field, it will experience a force proportional to the current in the conductor, and to
the strength of the external magnetic field. As you are well aware of from playing with
magnets as a kid, opposite (North and South) polarities attract, while like polarities (North
and North, South and South) repel. The internal configuration of a DC motor is designed to
harness the magnetic interaction between a current-carrying conductor and an external
magnetic field to generate rotational motion.
Let's start by looking at a simple 2-pole DC electric motor (here red represents a
magnet or winding with a "North" polarization, while green represents a magnet or winding
with a "South" polarization).

Fig 5.2 Magnetic winding

Every DC motor has six basic parts -- axle, rotor (armature), stator, commutator, field
magnet(s), and brushes. In most common DC motors, the external magnetic field is produced
by high-strength permanent magnets. The stator is the stationary part of the motor -- this
includes the motor casing, as well as two or more permanent magnet pole pieces. The rotor
(together with the axle and attached commutator) rotate with respect to the stator. The rotor
consists of windings (generally on a core), the windings being electrically connected to the
commutator. The above diagram shows a common motor layout -- with the rotor inside the
stator (field) magnets.
The geometry of the brushes, commutator contacts, and rotor windings are such that when
power is applied, the polarities of the energized winding and the stator magnet(s) are
misaligned, and the rotor will rotate until it is almost aligned with the stator's field magnets.
As the rotor reaches alignment, the brushes move to the next commutator contacts, and

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energize the next winding. Given our example two-pole motor, the rotation reverses the
direction of current through the rotor winding, leading to a "flip" of the rotor's magnetic field,
driving it to continue rotating.
In real life, though, DC motors will always have more than two poles (three is a very
common number). In particular, this avoids "dead spots" in the commutator. You can imagine
how with our example two-pole motor, if the rotor is exactly at the middle of its rotation
(perfectly aligned with the field magnets), it will get "stuck" there. Meanwhile, with a two-
pole motor, there is a moment where the commutator shorts out the power supply. This would
be bad for the power supply, waste energy, and damage motor components as well. Yet
another disadvantage of such a simple motor is that it would exhibit a high amount of torque
"ripple" (the amount of torque it could produce is cyclic with the position of the rotor).

So since most small DC motors are of a three-pole design, let's tinker with the workings of
one via an interactive animation (JavaScript required):

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Top of Form
A few things from this -- namely, one pole is fully energized at a time
(but two others are "partially" energized). As each brush transitions from one
commutator contact to the next, one coil's field will rapidly collapse, as the next coil's field
will rapidly charge up (this occurs within a few microsecond). We'll see more about the
effects of this later, but in the meantime you can see that this is a direct result of the coil
windings' series wiring:

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 .

There's probably no better way to see how an average DC motor is put together, than by just
opening one up. Unfortunately this is tedious work, as well as requiring the destruction of a
perfectly good motor.
The guts of a disassembled Mabuchi FF-030-PN motor (the same model that Solarbotics
sells) are available for (on 10 lines / cm graph paper). This is a basic 3-pole DC motor, with 2
brushes and three commutator contacts.
The use of an iron core armature (as in the Mabuchi, above) is quite common, and has a
number of advantages. First off, the iron core provides a strong, rigid support for the
windings -- a particularly important consideration for high-torque motors. The core also
conducts heat away from the rotor windings, allowing the motor to be driven harder than
might otherwise be the case. Iron core construction is also relatively inexpensive compared
with other construction types.
But iron core construction also has several disadvantages. The iron armature has a relatively
high inertia which limits motor acceleration. This construction also results in high winding
inductances which limit brush and commutator life.
In small motors, an alternative design is often used which features a 'coreless' armature
winding. This design depends upon the coil wire itself for structural integrity. As a result, the
armature is hollow, and the permanent magnet can be mounted inside the rotor coil. Coreless
DC motors have much lower armature inductance than iron-core motors of comparable size,
extending brush and commutator life.re

Fig 5.3 Winding coil assembly

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 .

The coreless design also allows manufacturers to build smaller motors; meanwhile, due to the
lack of iron in their rotors, coreless motors are somewhat prone to overheating. As a result,
this design is generally used just in small, low-power motors. Beamers will most often see
coreless DC motors in the form of pager motors.
Again, disassembling a coreless motor can be instructive -- in this case, my hapless
victim was a cheap pager vibrator motor. The guts of this disassembled motor are available
(on 10 lines / cm graph paper). This is (or more accurately, was) a 3-pole coreless DC motor.

SPUR GEAR
Spur gears are the simplest, and probably most common, type of gear. Their general
form is a cylinder or disk (a disk is just a short cylinder). The teeth project radially, and with
these "straight-cut gears", the leading edges of the teeth are aligned parallel to the axis of
rotation. These gears can only mesh correctly if they are fitted to parallel axles.
Spur gears are wheels with teeth that mesh together. Spur gears are used to change the
speed and force of a rotating axle.
How much the speed and force change depends on the gear ratio. The gear ratio is the ratio of
the number of teeth on the pair of gears that are meshed. The first gear in the pair is on the
input axle. For example, this could be the gear on the axle of the motor. The second gear in
the pair is on the output axle. This could be the axle of the wheel. The gear ratio is the ratio
number of teeth of the gear on the output axle to the number of teeth of the gear on the input
axle. For example, this picture shows an 8 tooth spur gear meshed with a 40 tooth spur gear.
If the 8 tooth gear is on the input axle, and the 40 tooth gear is on the output axle, then the
gear ratio for this gear pair is 40 to 8. This can be simplified to 5 to 1.
What this means is it takes 5 revolutions of the input gear to make 1 revolution of the
output gear. This results in a slowdown of the output gear by a factor of 5. It also increases
the force of the output gear by a factor of 5. If the input and output axles are reversed, then
the gear ratio would be 1 to 5. That means the output axle would rotate 5 times faster than the
input axle, but have 5 times as less force.
Spur gears change the direction of rotation. If the input axle rotates clockwise, then
the output axle would rotate counter clockwise.

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 .

Lead screw
A leadscrew (or lead screw), also known as a power screw or translation screw, is a
screw designed to translate radial motion into linear motion. Common applications are
machine slides (such as in machine tools), vises, presses, and jacks.

A leadscrew nut and screw mate with rubbing surfaces, and consequently they have a
relatively high friction and stiction compared to mechanical parts which mate with rolling
surfaces and bearings. Their efficiency is typically between 25 and 70%, with higher pitch
screws tending to be more efficient. A higher performing, and more expensive, alternative is
the ball screw.

The high internal friction means that leadscrew systems are not usually capable of continuous
operation at high speed, as they will overheat. Due to inherently high stiction, the typical
screw is self-locking (i.e. when stopped, a linear force on the nut will not apply a torque to
the screw) and are often used in applications where backdriving is unacceptable, like holding
vertical loads or in hand cranked machine tools.

Leadscrews are typically used well greased, but, with an appropriate nut, it may be run dry
with somewhat higher friction. There is often a choice of nuts, and manufacturers will specify
screw and nut combinations set.

The mechanical advantage of a leadscrew is determined by the screw pitch and lead. For
multi-start screws the mechanical advantage is lower, but the traveling speed is better.

Backlash can be reduced with the use of a second nut to create a static loading
force known as preload; alternately, the nut can be cut along a radius and
preloaded by clamping that cut back together.

A lead screw will back drive. A leadscrew's tendency to backdrive depends on

its thread helix angle, coefficient of friction of the interface of the components
(screw/nut) and the included angle of the thread form. In general, a steel acme thread and
bronze nut will back drive when the helix angle of the thread is greater than 20°.

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 .

Advantages & disadvantages

The advantages of a leadscrew are:

 Large load carrying capability

 Compact
 Simple to design
 Easy to manufacture; no specialized machinery is required
 Large mechanical advantage
 Precise and accurate linear motion
 Smooth, quiet, and low maintenance
 Minimal number of parts
 Most are self-locking

The disadvantages are that most are not very efficient.

 Due to the low efficiency they cannot be used in continuous power

transmission applications.
 They also have a high degree for friction on the threads, which can wear the
threads out quickly.
 For square threads, the nut must be replaced; for trapezoidal threads, a split
nut may be used to compensate for the wear.

Wheel
A wheel is a circular device that is capable of rotating on its axis, facilitating
movement or transportation or performing labour in machines. A wheel together with an axle
overcomes friction by facilitating motion by rolling. In order for wheels to rotate a moment
needs to be applied to the wheel about its axis, either by way of gravity or by application of
another external force. Common examples are found in transport applications. More
generally the term is also used for other circular objects that rotate or turn, such as a Ship's
wheel and flywheel. The wheel most likely originated in ancient
The wheel is a device that enables efficient movement of an object across a surface where
there is a force pressing the object to the surface. Common examples are a cart drawn by a
35
 .

horse, and the rollers on an aircraft flap mechanism.

The wheel is not a machine, and should not be confused with the wheel and axle, one of the
simple machines. A driven wheel is a special case, that is a wheel and axle. Wheels are used
in conjunction with axles, either the wheel turns on the axle or the axle turns in the object
body. The mechanics are the same in either case. The normal force at the sliding interface is
the same. The sliding distance is reduced for a given distance of travel. The coefficient of
friction at the interface is usually lower.

Battery
In our project we are using secondary type battery. It is rechargeable
Type.A battery is one or more electrochemical cells, which store chemical energy and make it
available as electric current. There are two types of batteries, primary (disposable) and
secondary (rechargeable), both of which convert chemical energy to electrical energy.
Primary batteries can only be used once because they use up their chemicals in an irreversible
reaction. Secondary batteries can be recharged because the chemical reactions they use are
reversible; they are recharged by running a charging current through the battery, but in the
opposite direction of the discharge current. Secondary, also called rechargeable batteries can
be charged and discharged many times before wearing out. After wearing out some batteries
can be recycled.
Batteries have gained popularity as they became portable and useful for many
purposes. The use of batteries has created many environmental concerns, such as toxic metal
pollution. A battery is a device that converts chemical energy directly to electrical energy it
consists of one or more voltaic cells. Each voltaic cell consists of two half cells connected in
series by a conductive electrolyte.

One half-cell is the positive electrode, and the other is the negative electrode. The
electrodes do not touch each other but are electrically connected by the electrolyte, which can
be either solid or liquid. A battery can be simply modeled as a perfect voltage source which
has its own resistance, the resulting voltage across the load depends on the ratio of the
battery's internal resistance to the resistance of the load.
When the battery is fresh, its internal resistance is low, so the voltage across the load
is almost equal to that of the battery's internal voltage source. As the battery runs down and

36
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its internal resistance increases, the voltage drop across its internal resistance increases, so the
voltage at its terminals decreases, and the battery's ability to deliver power to the load
decreases.

Fig 5.4 Internal voltage meter

Control unit
In our project the main device is micro controller. It is help to control the whole unit
of this project. In this we are using three motors to run the vehicle and move the lifting
arrangement on up and down all the motors are connected to the control unit. The movement
of vehicle forward and reverse, turning left and right and moving up and down are controlled
by keypad in the control unit so the control unit is the main part of this equipment. The
control unit is connected with the battery.
Microcontrollers are destined to play an increasingly important role in revolutionizing
various industries and influencing our day to day life more strongly than one can imagine.
Since its emergence in the early 1980's the microcontroller has been recognized as a general
purpose building block for intelligent digital systems. It is finding using diverse area, starting
from simple children's toys to highly complex spacecraft. Because of its versatility and many
advantages, the application domain has spread in all conceivable directions, making it
ubiquitous. As a consequence, it has generate a great deal of interest and enthusiasm among
students, teachers and practicing engineers, creating an acute education need for imparting
the knowledge of microcontroller based system design and development. It identifies

the vital features responsible for their tremendous impact; the acute educational
need created by them and provides a glimpse of the major application area.

37
 .

Advantages of microcontrollers

If a system is developed with a microprocessor, the designer has to go for

external memory such as RAM, ROM or EPROM and peripherals and hence the size of the
PCB will be large enough to hold all the required peripherals. But, the micro controller has
got all these peripheral facilities on a single chip so development of a similar system with a
micro controller reduces PCB size and cost of the design.

One of the major differences between a micro controller and a microprocessor is that
a controller often deals with bits , not bytes as in the real world application, for example
switch contacts can only be open or close, indicators should be lit or dark and motors can be
either turned on or off and so forth.

38
 Chapter 6

Merits & demerits

MERITS
 Easy to operate
 Very less maintenance
 No stress for handicapped peoples

DEMERITS
 Cost is high

39
 Chapter 7

Conclusion and future scope

Used in physically disabled persons in home uses

Used for hospital patients, etc,...

40
 Chapter 8
Cost estimation

SL.NO NAME OF THE QTY AMOUNT

COMPONENTS IN Rs
1. Dc Motor 1 1,200

2. Ms Pipe 4 1,500

3. Bearings 4 800 (200 each)

4. Tyre 2 600

5. Fly wheel 2 400

6. Motor Drive 1 1,700

7. Ultrasonic Sensor 1 500

8. Relay 5 800

9. Arduino Nano 1 1300

10. Gear 2 1000

11. Connecting 3 400

Wires
12. Sensor 2 300

13. Collecting Box 1 500

14. Battery 2 1000

TOTAL COST 9,800

41
 Reference

[1] Algarni S, Mellouli S and Abhilash, “Performance Analysis of a Solar

Powered Wheel chair”, Journal of Engineering Technology, Volume 6, Special
Issue on Technology Innovation and Applications, October 2017, pp.212-216.

[2] Madhusudhan T, Madhav P, Pranav S Meghlal and Rahul Ashok, “Design

and Development of Wheelchair Accessible Ramp for Scooters”, International
Journal of Innovative Research in Science, Engineering and Technology
(IJIRSET), Volume 6, Issue 6, ISSN (online): 2319-8753, ISSN (print): 2347-
6710, June 2017, pp.11534-11540.

[3] Jawale P R, Gabhane A R, Baje K G and Patil D N, “A Review on Modern

Hybrid Tricycle for Handicapped Person”, International Journal of Research in
Advent Technology, Special Issue Nation Conference “CONVERGENCE 2017”,(
E-ISSN: 2321- 9637), April 2017,pp.113-118.

[4] Ravi Solanki, Jigar Rathod and Vaibhav Patel, “Modification of Delta
Tricycle”, International Journal of Novel Research and Developement (IJNRD),
Volume 2, Issue 4, ISSN:2456-4184, www.ijnrd.org, April 2017, pp.35-38.

[5] Mahadi Hasan Masud, Md. Shamim Akhter and Sadequl Islam, “ Design,
Construction and Performance study of a solar Assisted Tri-cycle”, Periodica
Polytechnica Mechanical Engineering, Volume 61(3), revision 06, March 2017,
https://doi.org/10.3311/PPme.10240, pp.234-241.
[6] Sachin.s.raj, Prabhu P, Parthipan M and Rakesh varma S, “Design and
Fabrication of Magnetic Tricycle for Disabled People”, International Conference
on Innovative Researches in Engineering in Engineering, Science & Technology
(IER-IREST’ 17), (2017), pp.9-12. [7] Devaneyan S and Kirubakaran V “Solar
Powered Electric Tricycle for Physically Challenged Person”, International

42
Journal of Science, Engineering and Technology Research, Volume 5, Issue 12,
ISSN: 2278-7798, December 2016, pp.3475-3478.

43
 Other material reference

1. Design data book -P.S.G.Tech.

2. Machine tool design handbook –Central machine tool Institute,

Bangalore.
3. Strength of Materials -R.S.Kurmi

4. Manufaturing Technology -M.Haslehurst.

5.Design of machine elements- R.s.Kurumi

6.Automobile Engineering – Dr. Kirpal Singh

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Project photography

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