Senior Design Final Report

Senior Design Final Report
Electric Scooter – Group #6
December 7th
, 2015
Ovidiu Ciurbe
Gabriela Jaquinto
Borna Mali
Pawel Truchan

Senior Design Final Report | 2
Group# 6 Electric Scooter
Abstract
This report includes detailed information about the development of an electric scooter for a nine
year old Anja Hermann. The Hermann family had been struggling over the years to find a mobility
device for their daughter who lives with cerebral palsy which affects her body movement and muscle
coordination. Due to her limitations and their preferences, it was hard to find an electric scooter that
would fit her needs without the need of making any modifications to it. Our group decided to take on this
project in order to give Anja the opportunity to easily get to places in something she actually loves.

Acknowledgements
First and foremost, as a team we would like to express our deepest appreciation to those who
have helped us through this journey and made it possible to complete this project. A special gratitude we
give to our professor, Dr. Michael A. Brown, who has always shown a great amount of confidence in
our abilities and whose contribution in stimulating suggestions and encouragement was essential
towards our final results.
Furthermore we would also like to acknowledge with much appreciation the crucial role of the
staff in the machine shop at UIC, who gave the permission to use all required equipment and the
necessary guidance to complete re-designed battery case. Many thanks go to Professor Michael J. Scott,
who agreed to be our mentor and provided much help every step of the way. A very special thanks to
Mr. Ioan Ciurbe, one of our teammate’s father, who invested his full effort in guiding us towards
achieving our goal and by machining custom parts that were crucial for our modifications. Last but not
least, we are deeply indebted to Dr. Sabri Cetinkunt and his teaching assistants Bobak Shahian and
Sakthish Rajan, who played a major role in helping us reduce the maximum speed of the electric
scooter.
Finally, we would like to thank the Hermann Family for making themselves available
innumerous times for our meetings and keeping an extremely positive attitude about this project. Our
most special thanks, however, goes to Anja who changed the way we see the world and gave us more
than enough motivation to do our very best job!

TABLE OF CONTENTS
Abstract Error! Bookmark not defined.
Acknowledgements 3
Introduction 5
Project Formulation 6
2.1 Customer Requirements 6
2.2Project Management - GANT Chart 9
Design Considerations 11
3.1 Design Alternatives 11
3.2 Fish Bone Diagram 12
3.3 Decision Matrix 14
3.4 Financial Analysis 16
Mechanical and Design Improvements 17
4.1 CAD Drawings 17
4.2 Modifications 29
Conclusion and Suggestions 41
Appendices 42
Apendix 1 – Decision Matrices 42

Introduction
Anya is a nine year old girl with cerebral palsy (CP) who needed an electric scooter to help her
move around during the day. Standing for a child with CP is better for overall long-term joint health but
only wheelchairs or seated scooters are available in the market. A powered mobility device would aid
her in maintaining her independence and also improve her quality of life. For this reason, we decided to
take on this project as we were very happy to help her to change her riding experience. We designed,
modified and improved an existing electric scooter upon which she can stand and have the option to sit
if needed. During the first semester of Senior Design, we developed a project charter to clarify customer
requirements, a GANT chart to ensure on-time delivery, used fish bone diagrams to understand the
problem, and finally used a decision matix to make a decision in terms of which route we should go
about conducting this project. During the second semster, we executed our plan by performing all
modifications on the existing scooter, designing all modification drawings based on the actual product,
and performing a cost analysis for all the modifications done. The modifications were broken down into
five key areas:
1. Battery Case Modification
2. New Seat Design
3. Folding Mechanism
4. Hand Brake Adjustment
5. Maximum Speed Reduction

Project Formulation
2.1 Customer Requirements
A project charter was developed to summarize the customer requirements and our final
agreement. The charter provides a preliminary delineation of roles and responsibilities, outlines the
project objectives, identifies the main risks, and defines the deadlines. It served as a reference of
authority for our project. Our sponsor was informed of all the changes that occur throughout the year
and signed the project charter.
1. GOAL(s)/ OBJECTIVE(s):
● Design an electric scooter to fit a child’s traveling needs.
● Design should be stable when maneuvering turns
● Design should fit in the trunk of a car
● Final Product Delivery
2. DEFINITION(s) OF DONE:
● Final presentation along with project files
● Final product delivery
3. KEY METRICS: Description
1. Weight 100 lbs or less
2. Accessibility Maneuvering tight spaces in public areas
3. Alignment Equal weight distribution
4. Stability Does not tip over
5. Life of product Child can use device for next several years while still growing
6. Wrist Throttle Thumb throttle causes discomfort
7. Reverse Ability to go reverse
8. Speed Not to exceed 7 mph
9. Operation Easy on/off button
10. Payload Basket to carry books
11. Restraint Device holding the user in place during operation
4. PROJECT TEAM: Primary Name/Phone #s: Email:

Customer Deana Herrman (773) 562-3213 deanaherrman@gmail.com
Faculty Advisor Michael J. Scott (312) 996-4354 mjscott@uic.edu
Project Manager Michael Brown (312) 996 - 3266
mabrown1@uic.edu
Project Team Members: Gabriela Jaquinto (847) 961-8858 gjaqui2@uic.edu
Ovidiu Ciurbe ociurb2@uic.edu
Borna Mali bmali3@uic.edu
Paweł Truchan (773) 329 - 0758 ptruch2@uic.edu
5. KEY ASSUMPTIONS AND NECESSARY CONDITIONS:
1. Anja is able to operate the device on her own.
6. TIMELINE/SCHEDULE
Major Project Milestones: Plan Date Latest Estimate Completion Date
Obtain Project Notebook 1/27/2015 1/27/2015 1/27/2015
Meet With Customer 2/5/2015 2/5/2015 2/5/2015
Complete Project Charter 2/12/2015 2/12/2015 2/12/2015
3 Initial Ideas 2/26/2015 3/3/2015 3/3/2015
Perform Analysis on 3 Ideas 3/5/2015 3/5/2015 3/19/2015
Present Ideas and Analysis to Customer 3/24/2015 3/31/2015 3/31/2015
Select a Final Design 4/7/2015 4/7/2015 4/7/2015
Work on final Report 4/14/2015 4/21/2015 4/21/2015
Project Report Submission 4/27/2015 5/1/2015 5/1/2015
Present Product to Customer 12/4/2015 12/4/2015 12/4/2015
7. Risks
Risk Description: Plan to address
1. Bad Alignment Analyze stability system
2. Instability Analyze device for turns
3. Mechanical Failures Analyze device failures
8. DOCUMENTATION:

Document #/Name Tools Required
Person(s)
Responsible
Description
1. Specifications
Pawel
Truchan/Borna Mali
Detailed list of customer
requirements
2.Fish Bone Diagram Word Ovidius
After analyzing 3 different design
models, a fishbone diagram will be
created for each option
3. Decision Matrices Excel/AHP Gabriela Jaquinto
AHP will be used to make a
selection between alternatives.
4. Final Design Selection All members
Discussion of decision matrices
results and final design selection.
5. Final Report Word All Members
Detailed description of all
necessary tools as well as steps
taken to complete this project
9. DOCUMENTATION
TIMELINE/SCHEDULE
SPRING SEMESTER
Document #/Name Key Dates:
1. Specifications 3/19/2015
2.Fish Bone Diagrams 4/7/2015
3.Decision Matrices 4/14/2015
4.Final Design Selection 4/16/2015
5. Final Report 4/27/2015
10. DOCUMENTATION
RISKS:
Risk description, owner, and plan to address (in order of
significance).
Document #/Name Risk Description / Plan to Address
Risk
Owner
1. Specifications
Inaccurate list with wrong quantities and dimensions,
will be doubled checked for mistakes
P.T
2. Final Design Selection
Possibility of selecting the wrong design. Lots of time
will be spent on this step analyzing potential risks and
costs associated with each alternative in order to justify a
quantitative final decision.
All
members
3. Quantitative Analysis
There may be pieces of information missing for this step
to be successfully completed. To prevent this from
happening, we will make sure to gather all necessary
data before getting started.
G.J./O.C.
4. CAD design
Inaccurate dimensions, will be reviewed prior to
submission
B.M
5. Final Report
Time may be an issue. We will try our very best to stick
to our schedule and make sure we can deliver the final
report on time.
All
members

2.2 Project Management - GANT Chart
The project management tool we chose for this project was a GANT chart. We created one for the
spring semester and another for the fall.
Spring Semester GANT Chart
2/15/152/25/15 3/7/15 3/17/153/27/15 4/6/15 4/16/154/26/15 5/6/15
Project Ideas
Finalize best 3 ideas
Design Specs
Design Selection
Decision Matrices
Individual Responsibilities
Spring GANTT Chart - Actual Dates

Fall Semester GANT Chart

Design Considerations
3.1 Design Alternatives
Based on customer requirements, budget and research, our team decided that there were three different
approaches that were feasible in order to complete the project:
1. Build a new scooter from scratch.
2. Buy a scooter and improve it.
3. Expand on her existing scooter.
The following diagram summarizes each of them.
8/24/15 9/13/15 10/3/15 10/23/15 11/12/15 12/2/15 12/22/15
Pick a Scooter to Buy
Individual Ideas
Team Decision
Purchase Selected Scooter
Meet up with Advisor
Meet up with Customer
Stress Analysis
CAD Drawings
Stress Analysis
Midterm Report
Individual Responsibilities
Group Meeting to Combine Tasks
Modifications
Adjustments and Modifications
Painting and Customizing
Project Delivery
Final Report+Presentation
Sponsor Product Delivery Meeting
Fall GANTT Chart - Actual Dates

3.2 Fish Bone Diagrams
A fish bone diagram was created for each alternative. They are shown below.
Build New Scooter from
Scratch
• The team would
start the design
process from
scratch, selecting
materials, designing
sketches, and
assembling it
together.
Buy a Scooter and Improve
It
• The team would
research alternative
options which are
available on the
market which bests
fits Anya’s needs
and then further
modify it to
encompass
everything she
would need.
Expand on Existing
Scooter
• Team would work on
the existing
scooter’s problems
and modify the
scooter to make
sure all the
requirements are
met for the client.

3.3 Decision Matrix
In order to make a decision concerning which approach to use, we used a procedure known as
Analytic hierarchy process (AHP). This process is a structured technique for organizing and analyzing,
based on mathematics and psychology. Rather than prescribing a "correct" decision, the AHP helped us
find one that best suits our goal and our understanding of the problem. It provided a comprehensive and
rational framework for structuring our decision problem, for representing and quantifying its elements,
for relating those elements to overall goals, and for evaluating alternative solutions. To start, we
decomposed our decision problem into a hierarchy of more easily comprehended sub-problems, each of
which would later be analyzed independently. Our goal is to select the most suitable approach of the
three previously discussed candidates. The factors to be considered are cost, speed of completion,
stability of the scooter, size, and appearance.
Figure 1: Decision Hierarchy
The criteria are defined as follows:
 Cost: value of money that will be used to complete the project.

 Speed of Completion: the amount of time needed to complete the project.
 Stability: the ability to maneuver turns and stop abruptly without tipping.
 Size: weight and measurement of the scooter.
 Appearance: how well the project will meet child’s expectations.
Based on these definitions, our team conducted extensive research on each criterion as it related
to each alternative and performed the AHP study1. Furthermore, after asking a series of questions to our
client and grade each matrix, we were able to get our final result from the study.
Criteria Weight Rank
Cost 0.142 3
Availability 0.229 2
Stability 0.515 1
Size 0.092 4
Appearance 0.023 5
Table 1: Criteria Ranking
Option Weight Rank
Build from Scratch 0.14 3
Buy and Improve 0.45 1
Expand on Existing 0.41 2
Table 2: Alternative Ranking
1
Appendix 1

3.4 Financial Analysis

Mechanical and Design Improvements
4.1 CAD Drawings

4.2 Modifications
Initially, this is how the scooter looked like once it was entirely assembled:
The following pages of this report contain information about all modifications performed by our
group which includes:
2. New Seat Design

The way the batteries were set up made it very hard for Anja to step on and off the scooter as
well as for her to stand with her legs apart. The following picture shows how the batteries were initially
mounted inside the plastic shroud:
To solve this problem, we entirely re-designed the battery case by inserting a new metal plate
that would allow the batteries to be mounted in a line a bit lower than they were originally:

We then re-inserted the batteries in series and covered them up with a new plastic top that is
strong enough to hold Anja’s weight if she needs to stand on top of it.

With this improved design, Anja no longer has to stand with her legs apart and can easily step on
and off the scooter.
2. New Seat Design
The seat the was included with the initial purchase did not provide any support for Anja’s legs
and was also hard to remove for transportation. As a solution, we purchased a bicycle seat which goes in
between her legs when she stands and created a new bar with better adjustments:

Due to its size and heavy weight, we needed make sure the scooter was as compact as possible in
order to be easily transported. In addition to ensuring easy removal of most features, we also designed a
folding mechanism for the handle bar. A hinge was developed, produced, and welded into the handle bar
as follows:

Another problem we encountered was that the hand brake was too far from the handle bar. In
order for Anja to use the brake, she would need to stretch out her hand and nearly need to let go of the
handle bar which is not safe. To overcome this problem, we simply bent the lever closer to the handlebar
so she can easily use it while maintaining grip on the handlebar.

The main issue we had in the development of this project involved reducing the maximum speed.
The original scooter had a maximum speed of 15 MPH which is not only unsafe for a child but also
unecessary for traveling purposes. Our goal in this project was to reduce the maximum speed to 3 MPH.
To do so, we connected a variable resistor and a potentiometer to the wire associated with speed. It is
very easy to adjust the maximum speed of the scooter by adjusting the potientometer. Ultimately,
everything was installed in the plastic case housing all the electrical components.

Conclusion and Suggestions
After every modification made by our team, the following pictures shows our final result:

We were able to deliver what was promised in the beginning of our project: a customized scooter
that fits and will grow with Anja. Our modifications included reducing the maximum speed from 15
MPH to 3MPH, developing a folding mechanism, improving the seat design, adjusting the battery case
to better fit her needs, and altering the position of the hand brake. Every modification that we made is
adjustable, meaning that our design has many settings in order to keep up with her growth. Furthermore,
as a team, we would like to make ourselves available to the Hermann Family in case any issues come
up.
This has been a wonderful journey for our team. We learned a lot about what we can and cannot
do. It certainly has been an eye opener about relating what we learned in our courses over the years and
applying it to a real life problem such as helping a nine year old with cerebral palsy. We are satisfied as
a team that we did our best and hope this will serve Anja for years to come. We enjoyed working
together along with other professionals in a range of fields to come together and resolve a problem that
actually matters. Even though we were only able to create one customized scooter for just one girl, we
are certain we made a positive impact on Anja’s life and that is something we will be proud of forever.

Appendix
Appendix A - Decision Matrices
Ranking of Criteria: GRADED BY OUR CLIENT
Cost Availability Stability Size Appearance
Cost 1.00 0.17 0.17 4.00 10.00
Availability 6.00 1.00 0.13 4.00 10.00
Stability 6.00 8.00 1.00 6.00 10.00
Size 0.25 0.25 0.17 1.00 10.00
Appearance 0.10 0.10 0.10 0.10 1.00
Normalizing the Data - dividing each entry in a column by the sum of the
entries in that column:
Cost Availability Stability Size Appearance
Cost 0.07 0.02 0.11 0.26 0.24
Availability 0.45 0.11 0.08 0.26 0.24
Stability 0.45 0.84 0.64 0.40 0.24
Size 0.02 0.03 0.11 0.07 0.24
Appearance 0.01 0.01 0.06 0.01 0.02
Last Step: Average of entries in each row
Average Rank
Cost 0.142 3
Availability 0.229 2

Stability 0.515 1
Size 0.092 4
Appearance 0.023 5
Cost
Build from
Scratch
Buy and
Improve
Expand on
Existing
Build from Scratch 1.00 0.25 0.10
Buy and Improve 4.00 1.00 0.13
Expand on Existing 10.00 8.00 1.00
Cost
Build from
Scratch
Buy and
Improve
Expand on
Existing
Cost Average
Build from Scratch 0.06
Buy and Improve 0.16
Expand on Existing 0.78
Ranking of Availability: GRADED BY OUR GROUP

Availability
Build from
Scratch
Buy and
Improve
Expand on
Existing
Availability
Build from
Scratch
Buy and
Improve
Expand on
Existing
Availability Average
Build from Scratch 0.05
Buy and Improve 0.27
Expand on Existing 0.68
Stability
Build from
Scratch
Buy and
Improve
Expand on
Existing
Build from
Scratch 1.00 0.25 0.33

Expand on
Existing 6.00 0.25 1.00
Normalizing the Data - dividing each entry in a column by
the sum of the entries in that column:
`Stability
Build from
Scratch
Buy and
Improve
Expand on
Existing
Build from
Scratch 0.07 0.17 0.06
Expand on
Existing 0.40 0.17 0.19
Stability Average
Build from
Scratch 0.10
Buy and
Improve 0.65
Expand on
Existing 0.25
Size
Build from
Scratch
Buy and
Improve
Expand on
Existing
Build from
Scratch
1.00 6.00 8.00
Expand on
Existing
0.13 0.25 1.00

Size
Build from
Scratch
Buy and
Improve
Expand on
Existing
Build from
Scratch
0.77 0.83 0.62
Expand on
Existing
0.10 0.03 0.08
Size Average
Build from
Scratch
0.74
Buy and
Improve
0.19
Expand on
Existing
0.07
Appearance
Build from
Scratch
Buy and
Improve
Expand on
Existing
Build from
Scratch 1.00 0.13 0.17
Expand on
Existing 6.00 0.25 1.00

Appearance
Build from
Scratch
Buy and
Improve
Expand on
Existing
Build from
Scratch 0.07 0.09 0.03
Expand on
Existing 0.40 0.18 0.19
Appearanc
e
Average
Build from
Scratch
0.06
Buy and
Improve
0.68
Expand on
Existing
0.26
FINALLY,
Alternatives WEIGHT Rank
Build from Scratch 0.14 3
Buy and Improve 0.45 1
Expand on Existing 0.41 2

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