Up, Step, Go = Learn,
Develop, Grow!
Walking Aid for Children with Developmental Delay
Presented By: Michelle Vito-Schaake
Bachelor of Engineering (Biomedical)
Supervisors: David Hobbs & Laura De Palma
ENGR5710A and B: Results Seminar
(9 Units)
Product Objective

Aims to provide a walking aid for children (1-2.5yrs
old)with gross motor Developmental Delay, which
encourages gait and muscle strengthening.
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
Resistance settings for muscle strengthening
Provides a stable base for a standing or walking toddler
Gait training ability
Room for growth
Child and user friendly
Kim Sim Lee (BME Masters)
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Initated project in 2012
Developmental Delay, Market Analysis
Possible geometric structure of product
My Project Objective

Control System

The product’s Control System aims to provide the following:
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Braking Mechanism: To further enhance anti-tipping feature, as well as
provide safety and assurance for toddler and parent
Toddler Training Modes: To strengthen muscles and furthermore,
encourage and challenge the child to stand up and walk
Developmental Delay (DD)

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Developmental Delay (DD) is
defined as an ongoing
development lag where a child
does meet their developmental
milestones within the expected
age bracket.
It affects the child’s ability to learn
and develop new skills, but does
not affect their ability to physically
grow.
Two clinical groups: Transient and
Persistent
Social
Intellectual
Language
Fine
Motor
Gross
Motor
Previous Studies

Cerebral Palsy : A form of
persistent DD
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Studies have shown muscle
strengthening does NOT
significantly affect their ability to
walk
Children with CP have different
muscle structure and struggle with
the control of their limbs
Children with transient DD have
normal developing muscles
Gait Development and Analysis

Most children are able to walk after 18
months.

Children with DD learn to walk at a
later stage, therefore they are heavier.

EMG studies show variation is walking
speed can trigger new muscle patterns

A.R Den Otter, A. G. (2004). Speed
Related Changes in Muscle Activity From
Normal to Very Slow Walking Speeds .
Gait and Posture, 19,270-278.
Current Walkers
Rifton Gait
Trainer
Kaye Walker
Boikido
Wooden
Wagon
Walker
Kid Walk
Common baby walkers.
Banned in Canada since
2004
Problem Statement
There are no existing walkers available in the market for
toddlers with gross motor DD
Project Process and Progress
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Literature review – understanding
developmental delay and gait
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Defining the specifications of the project
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Conceptualization of the system
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Selecting components of the design
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Component Testing
Current Stage
Requirements & Specifications
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Light weight
Able to carry 30kg load
max weight of child is approx. 25kg
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Encourage leg strengthening – resistance training
Encourage walking
Able to apply to existing walkers without making it look
like a walker for children with DD
Velocity range: 0 m/second – 0.4167 or 0.5556
m/second (1.5 – 2km/hr)
Conceptualization
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Project aim had two tasks:
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Primary focus was braking:
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Braking and Muscle Strengthening
systems
Basic Start/Stop – push buttons
Brake pad
Shifting the primary focus to gross
motor muscle training
Morphological & Weight Chart
Name
Brakes
(0.25)
Bike Brake
Automation
trolley brake
Centred Ring
on Axial
Gear system
Rod/ pistol
Fifth wheel
system
DC motor
Driven System
(x4 WD)
Colour
Energy
Efficient
(0.16)
Yes (0.096)
Yes (0.096)
Bulky and
Heavy
(0.16)
Likely (0.048)
Likely (0.048)
Safe
(0.25)
Cost
(0.16)
Total
Yes (0.15)
Yes (0.15)
Variable
Resistance
(0.25)
Yes (0.15)
No (0.025)
Likely (0.075)
Yes (0.15)
Likely (0.048)
Likely (0.048)
0.5670
0.5170
Yes (0.15)
Yes (0.15)
Likely (0.048)
No (0.096)
Yes (0.15)
Likely(0.048)
0.6420
Yes (0.15)
Yes (0.15)
Yes (0.15)
Yes (0.15)
No (0.025)
Yes (0.15)
Likely (0.048)
Yes (0.096)
Likely (0.048)
Yes (0.016)
No (0.096)
No (0.096)
Likely (0.075)
Likely (0.075)
Yes (0.15)
Likely (0.048)
Yes (0.096)
Likely (0.048)
0.4870
0.5380
0.6420
Yes (0.15)
Yes (0.15)
Yes (0.096)
Likely(0.048)
Yes (0.15)
Yes (0.096)
0.69
Probability (%)
60
30
10
Selected Design
Stage
Input (Force)
∑
Microcontroller
H-Bridge
Sensor measuring
Velocity
Aims to
Encourage…
1
Standing and balance
2
Taking the first steps
3
Taking more steps
with resistance
4
Walking with
resistance
Motor Driver
Output (Force)
Design Justification
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Advantages
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Based on the weight chart it is the
more logical solution
Fulfils both sections of the design
task – Braking and resistance training
Slight changes can be applied to suit
most systems
Cost efficient
Disadvantage
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Cannot be applied to all systems
Battery dependent
Manufacturing & Test Model
Engineering Block Diagram
Electronic Components
Input (Force)
Output (Force)
∑
Microcontroller
Arduino uC32
H-Bridge
L293D
Sensor
measuring
Velocity
Quadrature
Encoder
Motor Driver
DC Motor
50:1
Component Testing
Mode Setting: Sends 1 pulse of
voltage over a certain period of
time to the DC motor.
Where:
0 =1000 µs (Forward)
90 = 1500 µs (Stop)
180 = 2000 µs (reverse)
Component Testing Results
Indications of error involved:
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Unexpected behaviour
Disagreement with specifications
Inconsistent data between two
power sources with the same
input voltage
Problems with code?
Motor Setting vs KM/hr(10cm
wheel)
velocity (km/hr)
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2.5
2
1.5
1
0.5
0
KM/hr(10
cm)
0 22.5 45 67.5
Motor Setting
Motor Setting (0-45) vs Km/hr (10 cm)
6
5
4
Velocity
3
(km/hr)
2
Km/hr (10 cm)
1
0
Motor Mode
External Testing
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Needed an external validation method.
Testing solution – the use of a tachometer
DC regulated
power source
DC motor, arduino
and motor driver
Tachometer
External Testing Results
Revolutions per Minute (RPM) at set Voltage and PWM (Encoder Setting = 45)
Of DC motor with a 10cm wheel
Time (minutes)
1
2
3
6V
59.62 rpm
59.75 rpm
59.62 rpm
Voltage
9V
70.36 rpm
71.1 rpm
71.19 rpm
12V
121.89 rpm
121.86 rpm
122.45 rpm
4
Average rpm (rpm ± SD)
Tachometer
m/min
m/second
60.09 rpm
59.77 rpm ± 0.22
59 rpm
5.9
0.098
70.86 rpm
70.8775 rpm ± 0.37
70 rpm
7
0.116
122.16 rpm
122.09 rpm ± 0.28
121 rpm
12.1
0.201
Reasons:
• Inconsistent power source
• Lack of knowledge and understanding of the DC
motor’s behaviour
Future Work
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Implement and test the circuit design
Modification and improve design
(dependent on time)
Communication of final design
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Thesis Report
Expo and poster
Knowledge Gaps:
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Implementing a PID
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Defining the boundaries of each training stage
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Weight of the overall system
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Alternate power source in order to keep motor running
consistantly
Conclusion
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There are no existing walkers, customised for toddlers
with DD
Engineering design method - enables to evaluate solutions
in a logical and thorough manner.
End of year goal: To have a working prototype of a walking
aid for children with gross motor DD.