on DESIGN AND FABRICATION OF MULTI-PURPOSE …

Visvesvaraya Technological University, Belagavi

A Project Report

on

“DESIGN AND FABRICATION OF

MULTI-PURPOSE WHEELCHAIR FOR

DIFFERENTLY-ABLED PERSON” (KSCST Sponsored Project)

(Reference Number: 4OS_BE_0327)

submitted in partial fulfillment of the requirements for the award of degree of

BACHELOR OF ENGINEERING

in

MECHANICAL ENGINEERING

by

RAKSHITH R 4VV13ME082 SURAJ G D 4VV13ME111

RITESH N JOSHI 4VV13ME085 THRISHOOL R 4VV13ME114

Under the Guidance of

Dr. G V NAVEEN PRAKASH

B.E., M.Tech., Ph.D

Professor & PG Coordinator

Department of Mechanical Engineering

Vidyavardhaka College of Engineering Gokulam 3rd Stage, Mysuru 570002,

Karnataka, India

2016-2017

VIDYAVARDHAKA COLLEGE OF ENGINEERING Gokulam 3rd Stage, Mysuru - 570002, Karnataka

DEPARTMENT OF MECHANICAL ENGINEERING

CERTIFICATE

Certified that the project work entitled “DESIGN AND FABRICATION OF MULTI-

PURPOSE WHEELCHAIR FOR DIFFERENTLY-ABLED PERSON” is carried out by

RAKSHITH R 4VV13ME082 SURAJ G D 4VV13ME111

RITESH N JOSHI

4VV13ME085

THRISHOOL R 4VV13ME114

bonafide students of Vidyavardhaka College of Engineering in partial fulfillment for the

award of “Bachelor of Engineering” in Mechanical Engineering of the Visvesvaraya

Technological University, Belagavi during the year 2016-2017. It is certified that all

corrections/suggestions indicated for Internal Assessment have been incorporated in the

report deposited in the department library. The project report has been approved as it satisfies

the academic requirements in respect of Project work prescribed for the said Degree.

Dr. G V NAVEEN PRAKASH B.E., M.Tech., Ph.D

Professor & PG Coordinator

Project Guide

Dr. L J SUDEV BE., M.Tech., Ph.D

Head of the Department

Dr. B SADASHIVE GOWDA M.E., Ph.D

Principal

EXTERNAL VIVA

Name of the Student :

University Seat No :

Name of the Examiners Signature with Date

1.

2.

ACKNOWLEDGEMENT

It is our privilege to express gratitude to all those who inspired and guided us to

complete the project work. This work would have remained incomplete without direct

and indirect help of many people who have guided us in the success of this project work.

We are grateful to them.

We are grateful to our Guide Dr. G V Naveen Prakash, Professor & PG

Coordinator, Department of Mechanical Engineering for his guidance, constant support

and encouragement in completing the project work.

We thank our project coordinators Prof. Thamme Gowda C S, Assistant

professor and Prof. Vismay K G, Assistant Professor, Department of Mechanical

Engineering for his coordination and encouragement in completing the project work.

We are grateful to Dr. L J Sudev, Professor & Head of the Department,

Mechanical Engineering and Dr. G B Krishnappa, R&D Dean, for their constant

support and encouragement in completing the project.

We take great pride in thanking Dr. B Sadashive Gowda, Principal for providing

congenial atmosphere and support for completion of our work.

We also thank our sponsor Karnataka State Council for Science and

Technology for their appreciation and support for completion of our project.

We thank all the faculties of the department, our parents and friends who helped

us directly and indirectly for the completion of our project work.

RAKSHITH R

RITESH N JOSHI

SURAJ G D

THRISHOOL R

DECLARATION

We, the students pursuing Bachelor of Engineering in Mechanical Engineering at

Vidyavardhaka College of Engineering, Mysuru, bearing the University Seat Numbers

4VV13ME082, 4VV13ME085, 4VV13ME111, 4VV13ME114, hereby declare that the

project work entitled “DESIGN AND FABRICATION OF MULTI-PURPOSE

WHEELCHAIR FOR DIFFERENTLY-ABLED PERSON” embodies report of the project

carried out by us at Vidyavardhaka College of Engineering, Mysuru, during the 8th semester

Bachelor of Engineering under the guidance of Dr. G V NAVEEN PRAKASH, Professor &

PG Coordinator, Department of Mechanical Engineering. No part of this project is submitted

for the award of degree or diploma in any university or institution previously.

Place: Mysuru

Date:

RAKSHITH R

(4VV13ME082)

RITESH N JOSHI

(4VV13ME085)

SURAJ G D

(4VV13ME111)

THRISHOOL R

(4VV13ME114)

ABSTRACT

One of the basic problems of user on manual wheelchair is overcoming architectural

barriers (kerbs, stairs etc.) on its way. Even though many research studies have been reported

in different fields to increase the independence of wheelchair users, the question of overcoming

obstacles by a wheelchair always remains as topic of discussion for many researchers. In our

project a motor operated stair climbing wheelchair concept which can overcome the

architectural barriers to a considerable extent has been developed. This project involves the

design of an ergonomically designed battery powered wheel chair for multipurpose use. Stair

climbing functionality is embedded in the design through its structure and mechanism. All the

design parameters of wheelchair were based on the standard design of the stairs in India. Major

part of the project focuses on the proposed design concept and concludes by discussing upon

the physical working model developed for the proposed design solution.

Keywords: Architectural barriers, motor operated, stair climbing

CONTENTS

Chapter

No. Title

Page

No.

1

1.1

1.1.1

1.1.2

1.1.3

1.2

1.2.1

INTRODUCTION

Wheelchair

History

Types of wheelchairs

Limitations

Stairs

Standard stair size

1-8

1

1

1

5

6

8

2

2.1

2.2

2.2.1

2.2.2

2.2.3

2.3

2.4

LITERATURE SURVEY

Manual wheelchairs with stair-climbing capabilities

Power wheelchairs with stair-climbing capabilities

Wheelchairs that use wheels or wheel clusters to climb

Wheelchairs and wheelchair carriers that use legs to climb

Wheelchairs and wheelchair carriers that use a rubber track to climb

Summary

Objective

9-18

9

13

13

15

16

18

18

3

3.1

3.2

3.2.1

3.2.2

3.2.3

3.2.4

3.2.5

3.2.6

METHODOLOGY

Description

Principle Parts

Frame

Lobe wheels

Chair

Gear motor

Transmission system

Assembly

19-32

19

19

22

24

28

28

30

30

4

4.1

WORKING MECHANISM

Calculations

33-36

35

5

5.1

5.2

5.3

5.3.1

RESULTS & DISCUSSION

Advantages & Disadvantages

Applications

Engineering practices

Human Safety

37-39

38

38

39

39

5.3.2

5.3.3

5.3.4

Environmental impact

Ethical practices

Cost Consideration

39

39

39

6 BILL OF MATERIALS 40

7 CONCLUSIONS 41

8 FUTURE SCOPE 42

REFERENCES 43-44

ANNEXURE – I 45-46

ANNEXURE – II 47

LIST OF FIGURES

Figure

No. Description

Page

No.

1.1

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

1.10

Manual self-propelled wheelchair

Manual attendant-propelled wheelchair

Powered wheelchair

Mobility scooter

Single arm drive wheelchair

Reclining wheelchair

Sports wheelchair

All-terrain wheelchair

Stair terminologies

Standard stair size

2

2

3

3

4

4

5

5

7

8

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

2.9

2.10

2.11

2.12

2.13

Ernesto Blanco's Wheelchair Climbing a Staircase

Manuscale Wheelchair

Vardaan Manual Stair-Climbing Wheelchair

Stairbike Climbing a Staircase

Zenith 3D Model

TGR Scoiattolo 2000 Wheelchair

Independence iBOT 4000 Mobility System

OB-EW-001 Observer Maximus

Zero Carrier Wheelchair

C-MAX U1 Climbing a Staircase

TopChair Wheelchair Descending a Staircase

TGR Explorer Powered Wheelchair

Stairmax Wheelchair Carrier

9

10

11

12

12

13

14

15

15

16

16

17

17

3.1

3.2

3.3

3.4

3.5

3.6

3.7

Frame design

Frame dimensions

Total deformation of the frame

FOS of the frame

Fatigue FOS of the frame

Maximum principal stress of the frame

Maximum principal strain of the frame

20

21

21

22

22

23

23

3.8

3.9

3.10

3.11

3.12

3.13

3.14

3.15

3.16

3.17

3.18

3.19

Human gait cycle

Wheel design

Wheel dimensions

Total deformation of the wheel

Maximum principal stress of the wheel

Maximum principal strain of the wheel

Seat tilting mechanism

Motor connection

Assembled wheelchair: Isometric view

Assembled wheelchair: Front view

Assembled wheelchair: Top view

Assembled wheelchair: Side view

24

25

25

26

27

27

28

29

30

31

31

32

4.1

4.2

Working mechanism

Mechanism top view

33

34

LIST OF TABLES

Table

No. Description

Page

No.

3.1

3.2

3.3

3.4

3.5

3.6

Properties of mild steel

Analysis parameters

Results of analysis

Properties of plywood

Specification of motor

Battery specifications

20

23

24

26

29

29

4.1 Chain, sprocket and center distance calculation 36

5.1 Results 37

6.1 Bill of materials 40

Department of Mechanical Engineering, VVCE, Mysuru Page 1

Design and fabrication of multi-purpose wheelchair for differently-abled person 2016-2017

CHAPTER 1

INTRODUCTION

One-fifth of the estimated global population, i.e. between 110 million and 190 million

people, experience significant disabilities. Disabilities of various parts such as eye, ear, hand,

leg etc. Limb disability is one of the disabilities which are caused due to various reasons such

as deformation by birth, war, disorders such as diabetes. Lower limb of sports person also

suffers huge blows while playing and are always at the risk of suffering severe injuries. These

injures sometimes may be a permanent disability.

1.1 WHEELCHAIR

1.1.1 HISTORY

The first records of wheeled seats being used for transporting disabled people date to three

centuries later in China; the Chinese used early wheelbarrows to move people as well as heavy

objects. A distinction between the two functions was not made for another several hundred

years, around 525 AD, when images of wheeled chairs made specifically to carry people begin

to occur in Chinese art.

Wheelchair is used by people who have difficulty in mobility. Generally people who use are,

Lower limb disabled people

Patients at the hospitals

Elderly people.

1.1.2 TYPES OF WHEELCHAIR

There are many types of wheelchairs available in the market like manual or powered wheelchair

and the choice of wheelchair depends upon the physical and mental ability of the user. General

types of wheelchairs are,



1.1.2.1 Manual self-propelled wheelchair

A self-propelled manual wheelchair incorporates a frame, seat, one or two footplates (footrests)

and four wheels: usually two caster wheels at the front and two large wheels at the back as seen

in Figure 1.1. There will generally also be a separate seat cushion. The larger rear wheels

usually have push-rims of slightly smaller diameter projecting just beyond the tyre; these allow

the user to manoeuvre the chair by pushing on them without requiring them to grasp the tyres.

Figure 1.1: Manual self-propelled wheelchair

1.1.2.2 Manual attendant-propelled wheelchairs

An attendant-propelled wheelchair is generally similar to a self-propelled manual wheelchair,

but with small diameter wheels at both front and rear as seen in Figure 1.2. The chair is

manoeuvred and controlled by a person standing at the rear and pushing on handles

incorporated into the frame. Braking is supplied directly by the attendant who will usually also

be provided with a foot- or hand-operated parking brake.

Figure 1.2: Manual attendant-propelled wheelchair

1.1.2.3 Powered wheelchairs

An electric-powered wheelchair, commonly called a "power chair" is a wheelchair which

additionally incorporates batteries and electric motors into the frame and that is controlled by

either the user or an attendant, most commonly via a small joystick mounted on the armrest, or

on the upper rear of the frame as seen in Figure 1.3.



Figure 1.3: Powered wheelchair

1.1.2.4 Mobility scooters

Mobility scooters share some features with power chairs, but primarily address a different

market segment, people with a limited ability to walk, but who might not otherwise consider

themselves disabled as seen in Figure 1.4. Smaller mobility scooters are typically three

wheeled, with a base on which is mounted a basic seat at the rear, with a control tiller at the

front. Larger scooters are frequently four-wheeled, with a much more substantial seat.

Figure 1.4: Mobility scooter

1.1.2.5 Single-arm drive wheelchairs

One-arm or single arm drive enables a user to self-propel a manual wheelchair using only a

single arm as seen in Figure1.5. The large wheel on the same side as the arm to be used is fitted

with two concentric handrims, one of smaller diameter than the other. On most models the

outer, smaller rim, is connected to the wheel on the opposite side by an inner concentric axle.

When both handrims are grasped together, the chair may be propelled forward or backward in

a straight line. When either hand-rim is moved independently, only a single wheel is used and

the chair will turn left or right in response to the hand-rim.



Figure 1.5: Single arm drive wheelchair

1.1.2.6 Reclining wheelchairs

Reclining or tilt-in-space wheelchairs have seating surfaces which can be tilted to various

angles as seen in figure 1.6. The original concept was developed by an orthotist, Hugh Barclay,

who worked with disabled children and observed that postural deformities such as scoliosis

could be supported or partially corrected by allowing the wheelchair user to relax in a tilted

position.

Figure 1.6: Reclining wheelchair

1.1.2.7 Sports wheelchairs

A range of disabled sports have been developed for disabled athletes,

including basketball, rugby, tennis, racing and dancing which can be seen in Figure 1.7. They

are usually non-folding (in order to increase rigidity), with a pronounced negative camber for

the wheels (which provides stability and is helpful for making sharp turns), and often are made

of composite, lightweight materials.



Figure1.7: Sports wheelchair

1.1.2.8 All-terrain wheelchairs

All-terrain wheelchairs can allow users to access terrain otherwise completely inaccessible to

a wheelchair user from figure 1.8. Two different formats have been developed. One hybridises

wheelchair and mountain bike technology, generally taking the form of a frame within which

the user sits and with four mountain bike wheels at the corners. In general there are no push-

rims and propulsion/braking is by pushing directly on the tyres.

Figure 1.8: All-terrain wheelchair

1.1.3 LIMITATIONS

Wheelchair has limitations against architectural barriers on its way. Although as per PWD 1995

act it is mandatory to provide an accessible environment in every public building but numerous

buildings in India are designed without considering accessibility for physically challenged and

wheel chair users. Many urban cities of India have addressed the problem by providing

alternatives for the architectural barriers like providing ramps at the entrance thresholds,



lowering kerbs, wheeler chair ramps, lifts etc. But still a wheelchair user has to negotiate few

architectural barriers.

Several studies have shown that both children and adults benefit substantially from access to a

means of independent mobility, including power wheelchairs, manual wheelchairs, scooters,

and walkers. Independent mobility increases vocational and educational opportunities, reduces

dependence on caregivers and family members, and promotes feelings of self-reliance. For

adults, independent mobility is an important aspect of self-esteem and plays a pivotal role in

“aging in place.” For example, if older people find it increasingly difficult to walk or wheel

themselves to the commode, they may do so less often or they may drink less fluid to reduce

the frequency of urination. If they become unable to walk or wheel themselves to the commode

and help is not routinely available in the home when needed, a move to a more enabling

environment (e.g., assisted living) may be necessary. Mobility limitations are the leading cause

of functional limitations among adults, with an estimated prevalence of 40 per 1,000 persons.

1.2 STAIRS

A stairway, staircase, stairwell, flight of stairs, or simply stairs is a construction designed to

bridge a large vertical distance by dividing it into smaller vertical distances, called steps. Stairs

may be straight, round, or may consist of two or more straight pieces connected at angles. The

step terminologies are as shown in the Figure 1.9.

Each step is composed of tread and riser.

Tread

The part of the stairway that is stepped on. It is constructed to the

same specifications (thickness) as any other flooring. The tread "depth" is measured from the

outer edge of the step to the vertical "riser" between steps. The "width" is measured from one

side to the other.

Riser

The vertical portion between each tread on the stair. This may be missing for an "open" stair

effect.



Nosing

An edge part of the tread that protrudes over the riser beneath. If it is present, this means that,

measured horizontally, the total "run" length of the stairs is not simply the sum of the tread

lengths, as the treads overlap each other.

The following stair measurements are important:

Figure 1.9: Stair terminologies

The rise height or rise of each step is measured from the top of one tread to the next.

It is not the physical height of the riser; the latter excludes the thickness of the tread. A

person using the stairs would move this distance vertically for each step taken.

The tread depth of a step is measured from the edge of the nosing to the vertical riser;

if the steps have no nosing, it is the same as the going; otherwise it is the going plus the

extent of one nosing.

The going of a step is measured from the edge of the nosing to the edge of nosing in

plan view. A person using the stairs would move this distance forward with each step

they take.

To avoid confusion, the number of steps in a set of stairs is always the number of

risers, not the number of treads.

The total run or total going of the stairs is the horizontal distance from the first riser

to the last riser. It is often not simply the sum of the individual tread lengths due to the

nosing overlapping between treads. If there are N steps, the total run equals N-1 times

the going: the tread of the last step is part of a landing and is not counted.

The total rise of the stairs is the height between floors (or landings) that the flight of

stairs is spanning. If there are N steps, the total rise equals N times the rise of each step.

https://en.wikipedia.org/wiki/File:Stairway_Measurements.svg



The slope or pitch of the stairs is the ratio between the rise and the going (not the tread

depth, due to the nosing). It is sometimes called the rake of the stairs. The pitch line is

the imaginary line along the tip of the nosing of the treads. In the UK, stair pitch is the

angle the pitch line makes with the horizontal, measured in degrees. The value of the

slope, as a ratio, is then the tangent of the pitch angle.

Headroom is the height above the nosing of a tread to the ceiling above it.

Walkline – for curved stairs, the inner radius of the curve may result in very narrow

treads. The "walkline" is the imaginary line some distance away from the inner edge on

which people are expected to walk. Building code will specify the distance. Building

codes will then specify the minimum tread size at the walkline.

1.2.1 STANDARD STAIR SIZE

Figure 1.10: Standard stair size

The standard stair size is shown in fig1.10. The stairs are constructed in every building based

on,

The average foot size of an adult for tread length i.e., 25.4 cm.

The riser height is based on the way the foot comes while coming down the stairs, the

recommended height is 19.7 cm.



CHAPTER 2

LITERATURE SURVEY

After conducting an intensive literature review, it was found that wheelchairs with stair-

climbing capacities can be categorized into two types; the battery powered and the manual

powered. Although there are plenty of powered wheelchairs available in the market place, there

are limited scholarly reviews published on manual or battery powered wheelchairs. Instead,

patent certificates, wheelchair descriptions, and operation manuals are available. Indeed, no

peer reviewed literature was found for manual wheelchairs. Some researchers have built scale

models or full size prototypes of their designs but little documentation has been published on

this type of wheelchairs.

2.1 MANUAL WHEELCHAIRS WITH STAIR-CLIMBING

CAPABILITIES

In 1962, Ernesto Blanco, while working at Massachusetts Institute of Technology (MIT),

designed a self-propelled stair-climbing wheelchair [1], but a full scale prototype was never

built. However, a small model of Blanco’s design was built to showcase how his wheelchair

would perform rolling in flat ground as well as how it would climb and descend stairs. Fig. 2.1

shows a picture of Blanco’s wheelchair model climbing a staircase. Although no peer reviewed

literature was published on Blanco’s wheelchair, the mechanism can be examined from the

description given in MIT’s website and picture of the model.

Figure 2.1 Ernesto Blanco's Wheelchair Climbing a Staircase [1]



The spokes that extend outward away from the drive wheels are loaded with springs. The

spokes are spaced in such a way that, as the wheelchair rolls on flat terrain; they are completely

compressed inward, allowing the wheelchair to roll entirely on its drive wheels. While climbing

or descending a staircase, the spokes project outward away from the drive wheels to engage

the top edges of the steps.

The contact points act as pivot points and allow the user to climb or descend softly. As the

drive wheels roll on top of the spokes, these are compressed inward allowing the drive wheels

to rest on the top flat surface of the step. Not much else can accurately be said of Blanco’s

wheelchair as no other literature was found.

Another manual stair-climbing wheelchair found is The Manuscale shown in Fig 2.2. Here,

again, little literature has been published on this wheelchair, from which the following

observations are made. The Manuscale moves on the drive and turning wheels as a typical

manual wheelchair. Before climbing, the wheelchair is backed in reverse just in front of the

staircase. The user then pulls on a handle bar which reclines the seat, drops the climbing

sprockets to the floor, and lifts the drive and turning wheels from the floor. In this position, the

wheelchair drive wheels are now connected to the climbing sprockets by a series of chains and

drive sprockets, such that, as the user pulls to turn the drive wheels, the chains drive the

climbing sprockets. As the sprockets move backward, they drop on the top of the first step and

lifts the wheelchair up. The user continues to pull on the drive wheels to continue climbing the

remaining steps.

Figure 2.2 Manuscale Wheelchair [2]

Although Manuscale is capable of climbing stairs, the climb is rather uncomfortable. The

climbing sprockets with only four spokes are spaced far apart from each other and thus slam

the user each time the sprocket turns 90 degrees. Considering the number of turns needed to

climb an average staircase, slamming the user and chair every quarter of a turn is not desirable



for the user or the wheelchair. In addition, it is observed that the right drive wheel controls the

right climbing sprocket and the left drive wheel controls the left climbing sprocket respectfully.

Having independent control of the climbing sprockets can be advantageous when it is required

to make turns during the climbing process. However, it can also sacrifice stability, comfort,

and reliability of the wheelchair and its components and provide an unpleasant experience for

the user. Last, the user powers the climbing sprockets by pulling on the drive wheel rims that

are now difficult to reach while on reclined position, causing strain to the user’s wrist joints.

As seen on the video, pulling on the drive wheels to climb a small wing of steps is tiring and

challenging for the user.

A third manual stair-climbing wheelchair found through an internet search is Vardaan. Figure

2.3 [3] is a wheelchair designed by a group of four engineering students at the Indian Institute

of Technology (IIT). Vardaan is capable of climbing a wing of stairs by pulling on handle bars

connected to sets of “Y” shaped wheels. The power arms are connected to ratchets and braking

systems making a safe and stable climb and descend. As with the previous wheelchairs, there

exist very little published documentation that further explains how Vardaan climbs. Lola Nayar

[4] describes the project and its innovative climbing procedure conducted by Shanu Sharma, et

al. and mentored by Prof. Kanpur. Currently, the wheelchair designed by Shanu Sharma has

been approved by the IIT science and technology departments for further research and possible

mass production.

Figure 2.3 Vardaan Manual Stair-Climbing Wheelchair [3]

The Stairbike shown in Fig. 2.4 is a working prototype of a manual stair-climbing wheelchair

designed to help active individuals with good condition who suffer from paraplegia [5]. With



limited literature published about the Stairbike the following observation can be assumed. The

user is reclined almost parallel to the ground in a very uncomfortable and unsafe position. One

can imagine the difficulty, strength and coordination required to bring the user to a rolling

position (upright) after climbing or descending a staircase. The two clusters of four wheels on

the back are powered by chains and pedals for the user to control with his/her hands.

Figure 2.4 Stairbike Climbing a Staircase [5]

The last reviewed manual wheelchair that claimed to have stair-climbing capabilities was

Zenith. This is a manual stair-climbing wheelchair conceptual design by Josefina Chaves-Posse

et al. shown in Fig. 2.5 in collaboration with the University of Alberta [19]. By observing the

picture of the wheelchair, we can derive that Zenith moves on two tracks on flat terrain and

climbing stairs. It can be observed that there are clusters of three legs with small wheels at the

ends that help during climbing mode.

Figure 2.5 Zenith 3D Model [19]

By pure observation one can assume that the Zenith’s climbing power tracks are controlled

when the user turns the drive wheels’ rims. Also, there appears to be a linear actuator between



the drivetrain and the user, possibly used to recline the seat as the wheelchair climbs the steps.

Little else can accurately be said about Zenith, as no published literature of any kind was found.

Efforts were made to contact the designer with little success.

This completes the summary of manual stair-climbing wheelchairs found in the literature.

Unfortunately, very few scientists and scholars have taken the subject seriously and research

and development of manual stair-climbing wheelchairs lags in development. Since little

information was derived from the limited literature on manual stair-climbing wheelchairs, the

focus is changed to power wheelchairs with stair-climbing capabilities.

2.2 POWER WHEELCHAIRS WITH STAIR-CLIMBING

CAPABILITIES

Power stair-climbing wheelchairs can be categorize in three types. The first type of powered

wheelchairs with stair-climbing capabilities uses wheels or clusters of wheels to climb steps.

The second type involves wheelchairs that use leg-like members to climb one step at the time.

The third type, involves wheelchairs that use a rubber track or some type of crawler to climb.

The following discussion centres on research of products available in today’s marketplace as

well as scholarly published literature.

2.2.1 WHEELCHAIRS THAT USE WHEELS OR WHEEL CLUSTERS

TO CLIMB

The first type of wheelchairs use wheels or clusters of wheels to climb. Fig. 2.6 shows the TGR

Scoiattolo 2000 Wheelchair [6]. This wheelchair is capable of carrying a paraplegic person

upstairs with the help of an assistant. An assistant refers to an adult individual who assists the

user (paraplegic user) to climb or descend the staircase.

Figure 2.6 TGR Scoiattolo 2000 Wheelchair [6]



The TRG Scoiattolo 2000 Wheelchair is equipped with a set of batteries and motors used to

ascend and descent stairs.

Figure 2.7 Independence iBOT 4000 Mobility System

The Independence iBOT 4000 Mobility System is a wheelchair that utilizes clusters of wheels

to climb stairs as shown in figure 2.7 [9]. This system manufactured by Independence

Technology, a Johnson & Johnson Company, is a wheelchair that can assist paraplegic patients

in moving on flat terrain as well as climbing steps without the need of an assistant. The iBOT

can maneuver flat terrain rolling on its four wheels, a function intended to be used primarly in

outdoor environments. In this function, the iBOT is capable of moving through soft or unstable

terrain such as grass, gravel, dirt, and beach sand. In addition, when the wheelchair moves over

a curve or incline, the cluster rotates proportionally to maintain a level seat and maximize the

tipping over factor of safety as described in [9].

Another wheelchair that uses its wheels to climb stairs is the OB-EW-001 Observer Maximus

as shown in Figure 2.8. This device utilizes two powerful motors to drive the front and the rear

wheels independently, making it a power 4WD wheelchair. The wheelchair also uses a

gyroscope to monitor the inclination of the chair when climbing stairs and ramps and a motor

to adjust the seat level with leveled ground.



Figure 2.8 OB-EW-001 Observer Maximus [10]

2.2.2 WHEELCHAIRS AND WHEELCHAIR CARRIERS THAT USE

LEGS TO CLIMB

The second type of stair-climbing wheelchairs and wheelchair carriers consists of leg-like

elements to dominate stairs. Fig. 2.9 shows the Zero Carrier wheelchair designed by Jianjun

Yuan et al. [12, 13]. Zero Carrier is an eight-legged wheelchair equipped with wheels attached

at the end of each leg. Furthermore, the legs are constructed from square tubing fitted inside a

bigger square tubing capable of compressing and expanding. All eight legs are independently

driven by eight motors giving the Zero Carrier the possibility to compress or expand any leg

independent from the rest.

Figure 2.9 Zero Carrier Wheelchair [12]



Wheelchair carriers that utilize leg-like elements to climb stairs include the C-MAX U1 by

AAT The Stairclimber People [11] as shown in Figure 2.10

C-MAX U1 is a wheelchair carrier that is strapped to the back of most manual wheelchairs.

The user requires an assistant to climb stairs. The carrier lifts up the user on two legs and the

assistant takes to position of the back legs to prevent it from falling back. The C-MAX U1 is

composed of an electric motor that runs a rack attached to the legs and pushes it downward

away from the main frame of the carrier.

Figure 2.10 C-MAX U1 Climbing a Staircase [11]

2.2.3 WHEELCHAIRS AND WHEELCHAIR CARRIERS THAT USE A

RUBBER TRACK TO CLIMB

The devices under this category are equipped with some type of climbing tracks often made of

rubber material to help climb stairs. Of all the types studied, these types seem to be the most

abundant and favorable by user as it is very smooth during climbing and descending. The

jerking or sudden acceleration change for these types of climbers is minimized.

The Topchair shown in Figure 2.11 is a powered stair-climbing wheelchair invented by Manse

De Chermont and first produced in 2007 by the Topchair Company [14], [15]. The Topchair

moves on flat ground like typical electric wheelchair and on climbing tracks to climb steps.

Figure 2.11 TopChair Wheelchair Descending a Staircase [14]



The TGR Explorer wheelchair is similar to Topchair and is shown in Figure 2.12, designed by

the Italian company TGR Instruments of Freedom [16] consists of two separate independent

systems; one system consists of three wheels used for flat ground navigation while the other

consists of a climbing track for climbing applications.

Figure 2.12 TGR Explorer Powered Wheelchair [16]

The Stairmax, designed by Lehnar Lifttechnik [20], a wheelchair carrier that can be adapted to

most manual wheelchairs is shown in Fig. 2.13. Stairmax climbs stairs without the use of an

assistant, as long as the user possesses good arm and finger functionality as described in the

operation manual [17]. The staircase is required to have at least one good handrail. In addition

to the climbing track, the Stairmax is equipped with a small wheel in the back to make turns.

Figure 2.13 Stairmax Wheelchair Carrier [17]



2.3 SUMMARY

From the many types of stair climbing wheelchairs, we can see that some of them like

Manuscale, Vardaan use manual method for movement and high effort might be needed to

climb the stairs. The person on the power wheelchair can sit in comfort while it climbs the

stairs but those wheelchairs are not available in India. Even if they can be imported from other

countries the total cost would be very high (i.e. around 9 lakhs). Hence an attempt is required

to make an indigenous and cost effective stair-climbing wheelchair.

2.4 OBJECTIVES

• To design a stair-climbing wheelchair for differently-abled person with lower limb

disability in order to increase their mobility

• To fabricate a stair-climbing wheelchair for differently-abled person with lower limb

disability



CHAPTER 3

METHODLOGY

3.1 DESCRIPTION

The method we followed to complete the project is as follows,

3.2 PRINCIPLE PARTS

The wheel chair consists of following principle parts,

3.2.1 Frame

3.2.2 Lobe wheels

3.2.3 Chair

3.2.4 Gear motor and Reduction box

3.2.5 Transmission system

SELECTION Selection of project

SURVEY Existing product

Scope for improvement

DESIGNDeisgn of frame and

wheel

Analysis of frame

and wheelCalculations

FABRICATION Procurement of material Machining

ASSEMBLY Fitting all the parts

Wiring

TESTINGTesting of

the wheelchair

RESULTSTabulation of

results obtained from testing



3.2.1 FRAME

A frame is a structural system that supports other components of a physical construction or

steel frame that limits the construction's extent. The frame was designed in solid edge V20

software. This frame was fabricated using MS pipe of outer diameter 25.4 mm and wall

thickness of 1.67mm. The frame can be divided into two parts rectangular part and leg part.

The rectangular part is used to hold the chair along with the tilting mechanism, drive shaft and

gear motor. The leg part is mainly used to hold the planetary wheels and driven shaft. The

dimensions of the rectangular part were chosen by considering the space required for a normal

person to sit comfortably and taking other ergonomic considerations. The properties of mild

steel is shown in table 3.1. The design of the frame in figures 3.1 and 3.2.

Table 3.1: Properties of mild steel

Properties Value

Density 7850 kg/m3

Young’s modulus 2x105 MPa

Poison ratio 0.3

Bulk modulus 1.66x105 MPa

Shear modulus 7.69x104 MPa

Tensile yield strength 250Mpa

Ultimate tensile strength 250Mpa

Compressive yield strength 460Mpa

Figure 3.1: Frame design



Figure 3.2: Frame dimensions

Frame Analysis

The analysis of the frame was done by using ANSYS 15.0. A load of 1500N was applied on

the centre of gravity and the deformation was analysed. The maximum deformation was found

to be 0.1mm. The safety factor for both static and fatigue loading were found good enough to

sustain the load. The safety factor of stress was 7.3 and the safety factor of fatigue was 2.6.

Maximum deformation was found at the plate on which the seat is being mounted. The stress

analysis was done by using the maximum principal stress theory. The loading and boundary

conditions applied during the analysis is as shown in table 3.2. The results of the analysis are

shown in figures 3.3 - figure 3.7.

Figure 3.3: Total deformation of the frame



Figure 3.4: FOS of the frame

Figure 3.5: Fatigue FOS of the frame



Figure 3.6: Maximum principal stress of the frame

Figure 3.7: Maximum principal strain of the frame

Table 3.2: Analysis parameters

Parameter Condition

Type of element tetrahedron

Boundary conditions Frame legs - fixed

Loading condition 1500N on the centre plate in negative y-

direction



The results of the analysis conducted on the frame is as shown in the table 3.3

Table 3.3: Results of analysis

Parameter Value

Max deformation 0.104mm

Factor of safety 7.3

Factor of safety fatigue 2.6

Maximum stress 43.91MPa

Maximum strain 0.00017

3.2.2 LOBE WHEELS

The stair climbing lobe wheel was designed by imitating the continuous foot movement in a

human gait cycle. The discontinuous wheel or stair climbing lobe wheel is designed to produce

similar phase cycle as stance and swing phase of human gait cycle as shown in figure 3.8.

The stair climbing lobe wheel is designed by considering foot size of human so that each

spoke shoe will adjust to the tread size automatically as shown in fig. The size between each

shoe is designed to negotiate maximum height of the riser in public building. It can negotiate

the step riser of range 75 – 185mm and tread width range 230 – 350mm which enables it to

access almost all the stairs in public areas. A light weight wheel with drum brakes was also

developed to control the movement of the shaft during ascending and descending process.

Figure 3.8: Human gait cycle



Figure 3.9: Lobed wheel design

Figure 3.10: Lobed wheel dimensions

Wheel Analysis

Wheel analysis was done by using ANSYS 15.0 software. In the analysis only deformation and

factor of safety of the wheel were considered in static position. The deformation, stress and

strain were calculated. The stress and strain were calculated based on maximum principal stress

theory. The properties of the plywood used to make the lobe wheel are mentioned in table 3.3.

The wheel analysis is shown in figures 3.11 to 3.13.



Table 3.4: Properties of plywood

Properties Value

Density 615 kg/m3

Young’s modulus 11 GPa

Poison’s ratio 0.25

Ultimate tensile strength 35 MPa

Yield compressive strength 31 MPa

Bulk modulus 9.19x103MPa

Shear modulus 4.24x103MPa

Figure 3.11: Total deformation of the wheel



Figure 3.12: Maximum principal stress of the wheel

Figure 3.13: Maximum principal strain of the wheel



3.2.3 CHAIR

The chair is one of the main parts of the wheelchair. The chair is fitted on to the frame of the

wheelchair. There is a tilting mechanism which connects the chair to the frame. There is need

for the tilting mechanism because the person sitting on the wheelchair may feel like slipping

from the seat because of the inclination of the stairs. The more the inclination of the stairs the

more he feels to slip from the chair. So with help of the seat tilting mechanism the person sitting

on the wheelchair can adjust the seat to the higher angle making the seat nearest to parallel to

the ground so that he may sit comfortably on the wheelchair while it is climbing stairs.

Figure 3.14: Seat tilting mechanism

The figure 3.15 shows the seat tilting mechanism where the knob is rotated to tilt the seat to

the higher position. The person sitting on the wheelchair can rotate the knob to change the

position of the seat when he wants to climb the stairs. With this the CG of the wheelchair will

be directed towards the ground.

3.2.4 GEAR MOTOR

A gear motor is used as locomotion unit and this motion is transmitted to the wheels through

shafts. This motor is mounted on a support provided by the shaft as shown in figure 3.16. The

dimensions and specifications of gear motor are obtained from standard motors available. A

gear motor of 180 watt power and 1:24 reduction gear ratio is used to reduce the speed to 60

rpm. Further the speed of the motor is reduced to 1.5 rpm using 1:40 ratio gearbox. The

specifications of the motor and the battery is shown in table 3.4 and 3.5 respectively

Knob to tilt the seat



Table 3.5: Specification of motor

Motor DC gear motor

Voltage 24V

Current 7.5 A

Duty S1

Speed 1440 rpm

Table 3.6: Battery specifications

Battery type Dry battery

Voltage 12 V

Current 7.5 Ah

The battery availability in the market is of 12V, so to provide the required voltage for the motor

two batteries are connected in series to make 24V. The connection for the motor is as shown

in figure 3.15. The motor and the battery is connected in series and the circuit is closed by

connecting a reverse switch. The reverse switch is used to change the direction of the motor so

that the person can either climb up or climb down the stairs.

Figure 3.15: Motor connection

Battery

DC gear motor with

reduction box Reversing switch in control of

the person on the wheelchair



3.2.5 TRANSMISSION SYSTEM

The transmission component of the wheelchair design is responsible for allowing the operator

to change gears between forward, neutral, and reverse movement. The transmission system

consists of the motor and chain-sprocket system. The motor with the reduction box is directly

mounted on the centre shaft with the help of mountings from the frame to hold the motor in

place. Therefore the motor is mounted rigidly, so that all the torque produced is completely

transferred to the wheels. Now the drive from the centre shaft is transferred to the front and

back shafts with the help of the chain sprocket arrangement. The front and back shafts drive

the wheels which climbs the stairs.

3.2.6 ASSEMBLY AND FABRICATION

Figure 3.16: Assembled wheelchair: Isometric view



Figure 3.17: Assembled wheelchair: Front view

Figure 3.18: Assembled wheelchair: Top view



Figure 3.19: Assembled wheelchair: Side view

The pipes were cut into required lengths and welded properly in correct positions to make the

frame. The plywood was cut to make the lobe shaped wheel. The shafts were machined to fit

as per requirement. The hubs were machined and holes were drilled so as to bolt the sprocket

into place. Then the parts were fitted as follows,

1. The front and rear shaft are held onto the frame with help of Plummer blocks.

2. The hub was fitted on the shafts and the wheels were fitted.

3. The motor and the battery were connected and the motor was fitted onto the

centre shaft.

4. The transmission from the motor to the front and rear shafts were made with

help of chains as shown the figure

5. The seat tilting mechanism was fitted to the chair and then it was fitted to the

frame.

6. The wiring for the motor and the battery were made.

The complete assembly of the wheelchair can be seen in figures 3.16 – 3.19.



CHAPTER 4

WORKING MECHANISM

The power is generated using a DC geared motor. This motor is coupled with a gear box. Due

to this the high speed, low torque input of the motor gets converted to low speed high torque

output. The geared box is coupled with the centre shaft which gets high torque but low rpm.

Two sets of sprockets are used. In both the sets all the sprockets are of 33 teeth. 2 sprockets are

mounted on the centre shaft; the rear shaft and the front shaft have one sprocket each.

The front and rear sprockets receive same high torque as they are on the centre shaft. This

torque is transmitted to both front and the rear shaft using a chain drive system. Since the

sprocket on the front and rear shaft are same there will be no change in the torque transmitted

and also the speed will remain same as the centre shaft. The mechanism can be seen in the

figure 4.1 and figure 4.2.

Figure 4.1: Working mechanism



Figure 4.2: Mechanism top view

Wheel chair when approach the stairs, the seat is tilted backwards. This makes the CG of the

system to shift towards the rear wheel. When the motor is switched on the wheelchair starts to

climb the stairs. The direction can be reversed by using a direction control switch.



4.1 CALCULATIONS

POWER CALCULATIONS

Torque required on a flat surface

Normal force (Fn) = force applied = mg

= 100*9.81

= 981N

Friction force (Ff) = Fn

= 0.2*981

= 196.2 N

Torque required = Ff*rw

= 196.2*0.18

= 35.316 N-m

Torque required on slope

Stair dimensions

Land: 254.0 mm

Rise: 177.8 mm

Slope of stair () = tan-1(177.8/254)

= 35o

Total mass acting (including setup) = 100kg = 100*9.8 = 981N

Normal force acting (Fn) = mgcos

= 100*9.81*cos (35o)

= 803.58 N

Frictional force (Ff) = Fn

= 0.2*803.58

= 160.7 N

Opposing force (Fo) = mgsin

= 100*9.81*sin (35o)

= 562.67 N

Torque required = (Ff + Fo) rw

= (160.7+562.67) 0.18

= 130.20 N-m



Motor torque generated

Power of motor (P) = 2NT

60

180 = 21.5T

60*0.6 (i.e., 0.6 = efficiency of the motor gear box)

Torque at the mid-shaft Tmid = 687.54N-m

Torque generated at wheels = Tmid / 1 (1:1 ratio sprocket arrangement)

= 687.5 / 1

= 687.5 N-m

The following formulae were used to determine the radius and the chain length

P = 2 r2 sin(180/Z2)

Lp = 2*c/15 + (Z1+Z2)/2 + P(Z1-Z2)/(4π2*c)

L = Lp*P

Cactual = P/4[Lp - (Z1+Z2)/2 +√{((Lp-(Z1+Z2)/2)2 – 8(20/2)2}]

Where, P = Pitch of chain

Lp = Pitch length of chain

L = Length of chain

c = center distance

Z1 = no. of teeth on driver

Z2 = no. of teeth on driven

Cactual = actual centre distance

The requirements of the chain-sprocket arrangement is as shown in the table 4.1

Table 4.1 Chain, sprocket and centre distance calculation

Parameter Value

Centre distance 426 mm

Pitch of chain 15 mm

Radius of driven sprocket 78.9 mm

Radius of driver sprocket 78.9 mm

Pitch length of chain 90 mm

Length of chain 1350 mm

Actual centre distance 424.81mm

No of teeth on driver 33

No of teeth on driven 33



CHAPTER 5

RESULTS AND DISCUSSION

After assembly of the wheelchair, we first tested it on normal surface where we loaded it

gradually. The results are shown in the table 7.1.

After successful pull up to 40 kg, people with weight around 60 kg and 80kg were made to sit

on the wheelchair. The motor was able to drive both the weights. The limit of the wheelchair

on the normal surface is 100kg.

Then we tested the wheelchair on a slope where the limit was around 80kg.

The wheelchair was tested on the stairs, the wheelchair could pull weights up to 50 kg so we

made person of 55kg weight sit on the wheelchair and the results are tabulated in the table

below.

Table 5.1 Results

LOADING CONDITION LOAD ON

WHEELCHAIR RESULT

On flat surface

No load Successful

20kg Successful

40kg Successful

60kg Successful

80kg Successful

100kg Successful

110kg Unsuccessful

On inclination (350)

No load Successful

20kg Successful

40kg Successful

60kg Successful

70kg Successful

80kg Unsuccessful



On stairs (350)

No load Successful

20kg Successful

30kg Successful

40kg Successful

45kg Successful

50kg Successful

55kg Successful

60kg Unsuccessful

5.1 ADVANTAGES AND DISADVANTAGES

5.1.1 ADVANTAGES

The wheelchair can be used to climb up or climb down the stairs.

The seat can be tilted to the required angle.

The wheelchair can climb stairs up to 7 inches in rise.

The operation of the wheelchair is easy.

The wheelchair is economical compared to the products in the existing market.

5.1.2 DISADVANTAGES

The wheelchair is heavy.

The capacity of the motor required to climb the stairs is high.

The battery capacity required to run the motor the motor is more.

The width of the wheelchair is more than the usual wheelchairs.

5.2 APPLICATIONS

Hospitals and public places

Institutions and office

Industries

Home



5.3 ENGINEERING PRACTICES

5.3.1 HUMAN SAFETY

The wheelchair is designed such that it can sustain loads up to 1500N i.e. ~150kg.

The motor speed is very low so that the person on the wheelchair does not feel any

jerks or any imbalances. Also the wheel design is such that there will be reduction in

vibration during the ascent and descent of stairs.

Seat tilting mechanism is provided to reduce the tendency of slipping of the person

sitting on the wheelchair during ascent.

5.3.2 ENVIRONMENTAL IMPACT

The wheelchair uses electric motor, so there are no harmful impact on the

environment.

The wheels which used are made out of wood which is environment friendly and does

not cause any damage to the stairs.

5.3.3 ETHICAL PRACTICES

All four of us in the project team contributed equally to the project.

There was no backstabbing or blaming on any team member.

The design of the wheelchair is based on available standards.

The details of other stair-climbing wheelchairs discussed are based on the available

literature

5.3.4 COST CONSIDRERATION

The imported stair-climbing wheelchair available is very costly to buy for a middle-

class people, where as our wheelchair is cost effective and parts are easily replaceable

and available in the market.



CHAPTER 6

BILL OF MATERIALS

The details of the particulars and their respective costs are as shown in the table 6.1

Table 6.1 Bill of materials

SL.

NO. PARTICULARS DESCRIPTION QUANTITY

UNIT

COST(Rs)

TOTAL

(Rs)

1 MS PIPE 25.4mm, 1.6mm wall

thickness 12.5kg 60 750

2 PLYWOOD 19mm thickness 4x3sqft 40 480

3 GEAR MOTOR 180 watts, 24 V 1 4000 4000

4 REDUCTION BOX 40:1 1 6000 6000

5 BATTERY 12 V, 7.6 A 2 650 1300

6 PLUMMER

BLOCK 17 mm, 19mm ID 6 225 1350

7 CHAIR NA 1 1000 1000

8 TILTINNG

MECHANISM NA 1 400 400

9 MS ROD 19mm 5kg 60 300

10 MS BLOCK NA 2kg 60 120

11 CHAIN &

SPROCKET 33 teeth 2 sets 700 1400

12 FASTENERS NA NA 300 300

13 LABOUR NA NA 4000 4000

14 MISCELLENEOUS NA NA 1000 1000

TOTAL Rs.22400



CHAPTER 7

CONCLUSIONS

The design of the wheelchair is compact and hence is able to move about in almost all the stairs

that we find at institutions, offices, industries and also at some homes. The design is made very

safe and there is no chance of failure of the frame and wheels under normal conditions

According to the tests conducted, the stair climbing wheelchair has a capacity of carrying a

load of 100kgs on flat surface. It has the ability to ascend a flight of stairs of 35-degree elevation

carrying a weight of 55kgs.



CHAPTER 8

FUTURE SCOPE

The frame weight can be reduced by using high strength lightweight materials such as

composites, carbon fibre.

The wheelchair can be automated by using electronics so that it will automatically sense

and climb the stairs.



REFERENCES

[1] M. A. (2006, Oct. 01). Professor Ernesto Blanco: A Lesson in Creative Engineering.

Available: http://mitadmissions.org/blogs/entry/ professor_ernesto_blanco_a_les

[2]Manuscale.(2013,Oct.01).’United Spinal' Techguide. Available:

http://www.usatechguide.org/itemreview.php?itemid=1612

[3] S. Sharma. (2012,Oct.01). Vardaan: stair climbing wheelchair. Available:

http://www.techpedia.in/award/project-detail/VARDAAN-A-Convertible-Manual-Stair-

Climbing-Wheelchair

[4] l. Nayar. (2012,oct.02). Where the pedal meets the mettle. Available:

http://photo.outlookindia.com/images/gallery/20120612/wheelchair_iit_k_20120625.jpg

[5] S. S. f. E. B. a. Innovation. (2008, Oct. 01). The first manual stair-climbing wheelchair in

the world. Available: http://www.enterprise-europe-

network.ch/marketplace/index.php?file=bbs-

show.php&bbsref=08%20CZ%200746%200IRD

[6] T. S. d. Liberta. (Oct. 14). Scoiattolo 2000. Available: http://www.tgr.it/

[7] Y. Sugahara, N. Yonezawa, and K. Kosuge, "A novel stair-climbing wheelchair with

transformable wheeled four-bar linkages," in Intelligent Robots and Systems (IROS), 2010

IEEE/RSJ International Conference on, 2010, pp. 3333-3339.

[8] TGR. (2009, Oct. 01). Scoiattolo 2000/E. Available:

https://www.youtube.com/watch?v=pm0695001Y8

[9] I. Technology. (2013, Oct. 01, 2013). iBOT 4000 mobility system without fold-flat-seating

user manual. Available: http://www.ibotnow.com/ manuals_without_foldflat.html

[10] Unlimited Wheelchair Observer. (2013, Oct. 01, 2013). OB-EW-001 Maximus. Available:

http://www.observer-mobility.com/obew01.html

[11] AAT The Stairclimber People. (2008, Oct. 01). The Universal Stair Climber C-max.

Available: http://www.aatgb.com/cmax_u1_powered_ stairclimber.html

[12] J. Y. S. Hirose, "Zero Carrier: A Novel Eight Leg-Wheels Hybrid Stair Climbing Mobile

Vehicle," Journal of Robotics and Mechatronics, vol. 17, pp. 44-51, 2004.



[13] Y. Jianjun and S. Hirose, "Research on leg-wheel hybrid stair-climbing robot, Zero

Carrier," in Robotics and Biomimetics, 2004. ROBIO 2004. IEEE International Conference on,

2004, pp. 654-659.

[14] TopChair. (2012, 09/10/2013). TopChair User Guide. Available:

http://www.topchair.fr/en/documentations/

[15] F. Barlin. (2007, Oct. 01). The new topchair stair climbing wheelchair ready for

commercialization. Available: http://www.sibaya.com/index.php/ topchair-stair-climbing-

wheelchair-ready-for-commercialization/ 119

[16] TGR Strumenti di Liberta. (Oct. 01). Explorer is the only one able to help ensure the total

independence to whom uses it. Available: http://www.tgr.it/?portfolio=explorer

[17] Lehner Lifttechnik. (2006, Oct. 01). Stairmax mobile Stairlift User Manual. Available:

http://www.lehner-lifttechnik.at/en/download

[18] J. Vlk, "Driving System for passing fly-over obstacles by invalid chair," US Patent US

7,394,023 B2, 2009.

[19] J. Chaves-Posse. (2010, Oct. 01). Zenith Wheelchair. Available:

http://www.coroflot.com/jopi/zenith-wheelchair

[20] AmeriGlide Accessibility Solutions. (Oct. 01). AmeriGlide Wheelchair Stair Climber.

Available: http://www.ameriglide-wayne-nj.com/item/AmeriGlide-AG-CLIMBER.html



ANNEXURE – I

PROGRAMME OUTCOMES (POs)

AND

PROGRAMME SPECIFIC OUTCOMES (PSOs)

I. PROGRAM OUTCOMES (POs)

1. Engineering knowledge: Apply the knowledge of mathematics, science, engineering

fundamentals, and an engineering specialization to the solution of complex engineering

problems.

2. Problem analysis: Identify, formulate, review literature, and analyze complex

engineering problems reaching substantiated conclusion using first principles of

mathematics, natural sciences, and engineering sciences.

3. Design/development of solutions: Design solutions for complex engineering problems

and design system components or processes that meet the specified needs with

appropriate consideration for the public health and safety, and the cultural, societal, and

environmental considerations.

4. Conduct investigation of complex problems: Use research-based knowledge and

research methods including design of experiments, analysis, and interpretation of data,

and synthesis of the information to provide valid conclusions.

5. Modern tool usage: Create, select, and apply appropriate techniques, resources, and

modern engineering and IT tools including prediction and modelling to complex

engineering activities with an understanding of the limitations.

6. The engineer and Society: Apply reasoning informed by the conceptual knowledge to

access social, health, safety, legal and cultural issues and the consequent responsibilities

relevant to the professional engineering practices

7. Environment and sustainability: Understand the impact of professional Engineering

solutions in societal and environmental context, and demonstrate the knowledge of, and

need for sustainable development.

8. Ethics: Apply ethical principles and commit to professional ethics and responsibilities

and norms of Engineering practice.



9. Individual and teamwork: Function effectively as an individual, and as a member or

leader in diverse teams, and in multidisciplinary settings

10. Communication: Communicate effectively on complex engineering activities with the

engineering community and with society at large, such as, being able to comprehend

and write effective reports and design documentation, make effective presentations, and

give and receive clear instructions.

11. Project management and Finance: Demonstrate knowledge and understanding of the

Engineering and Management principles and apply these to one's own work, as member

and leader in a team, to manage projects and in multidisciplinary environments.

12. Life-Long learning: Recognize the need for, and have the preparation and ability to

engage in independent and lifelong learning in the broadcast context of technological

change.

II. PROGRAM SPECIFIC OUTCOMES (PSOs)

1. Applied principles of basic science, mathematics, machine design, manufacturing,

thermal engineering and management to solve real life mechanical engineering

problems.

2. Use professional engineering practices and Strategies for the development, operation

and maintenance of mechanical system/ processes.

PO and POS Mapping:

PO1 PO2 PO3 PO4 PO5 PO6 PO7 PO8 PO9 PO10 PO11 PO12 PSO1 PSO2

3 3 3 3 2 2 3 3 3 3 2 3 3 2

Correlations: 3- High 2 – Medium 1 - Low

After completing the project work, we were able to acquire the above shown program outcomes

and program specific outcomes.



ANNEXURE – II

PROJECT PHOTOS

Isometric view of the wheelchair

Front view of the wheelchair

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