Up, Step, Go = Learn, Develop, Grow!
Walking Aid for Children with Developmental Delay
Presented By: Michelle Vito-SchaakeBachelor 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. 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) 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: 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) 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 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
Kaye Walker
Rifton Gait Trainer
Kid WalkBoikido Wooden Wagon Walker
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
Literature review – understanding developmental delay and gait
Defining the specifications of the project
Conceptualization of the system Selecting components of the design Component Testing
Current Stage
Engineering Design Process
Requirements & Specifications Light weight Able to carry 30kg load max weight of child is approx. 25kg
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
Project aim had two tasks: Braking and Muscle Strengthening
systems Primary focus was braking:
Basic Start/Stop – push buttons Brake pad
Shifting the primary focus to gross motor muscle training
Morphological & Weight Chart
Name Brakes(0.25)
Variable Resistance(0.25)
Energy Efficient(0.16)
Bulky and Heavy(0.16)
Safe(0.25)
Cost(0.16)
Total
Bike Brake Yes (0.15) Yes (0.15) Yes (0.096) Likely (0.048)
Likely (0.075)
Likely (0.048)
0.5670
Automation trolley brake
Yes (0.15) No (0.025) Yes (0.096) Likely (0.048)
Yes (0.15) Likely (0.048)
0.5170
Centred Ring on Axial
Yes (0.15) Yes (0.15) Likely (0.048)
No (0.096) Yes (0.15) Likely(0.048)
0.6420
Gear system
Yes (0.15) Yes (0.15) Likely (0.048)
Yes (0.016) Likely (0.075)
Likely (0.048)
0.4870
Rod/ pistol Yes (0.15) No (0.025) Yes (0.096) No (0.096) Likely (0.075)
Yes (0.096) 0.5380
Fifth wheel system
Yes (0.15)
Yes (0.15) Likely (0.048)
No (0.096) Yes (0.15) Likely (0.048)
0.6420
DC motor Driven System (x4 WD)
Yes (0.15) Yes (0.15) Yes (0.096) Likely(0.048) Yes (0.15) Yes (0.096) 0.69
Colour Probability (%)
60 30 10
Selected Design
H-BridgeMotor Driver
Microcontroller
Sensor measuring Velocity
∑Input (Force) Output
(Force)
Stage Aims to Encourage…
1 Standing and balance
2 Taking the first steps
3 Taking more steps with resistance
4 Walking with resistance
Design Justification Advantages
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
Cannot be applied to all systems
Battery dependent
Manufacturing & Test Model
Engineering Block Diagram
H-BridgeL293D
Motor Driver
DC Motor50:1
Microcontroller
Arduino uC32
Sensor measuring
VelocityQuadrature
Encoder
∑Input (Force) Output
(Force)
Electronic Components
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: Unexpected behaviour Disagreement with
specifications Inconsistent data between
two power sources with the same input voltage
Problems with code?
0
22.2
5 450
1
2
3
4
5
6
Motor Setting (0-45) vs Km/hr (10 cm)
Km/hr (10 cm)
Motor Mode
Velocity (km/hr)
022
.5 4567
.50
0.51
1.52
2.5
Motor Setting vs KM/hr(10cm wheel)
KM/hr(10cm)
Motor Setting
velo
cit
y (
km
/hr)
External Testing 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
Time (minutes) Voltage 6V 9V 12V
1 59.62 rpm 70.36 rpm 121.89 rpm2 59.75 rpm 71.1 rpm 121.86 rpm3 59.62 rpm 71.19 rpm 122.45 rpm
4 60.09 rpm 70.86 rpm 122.16 rpmAverage rpm (rpm ± SD) 59.77 rpm ± 0.22 70.8775 rpm ± 0.37 122.09 rpm ± 0.28
Tachometer 59 rpm 70 rpm 121 rpmm/min 5.9 7 12.1
m/second 0.098 0.116 0.201
Revolutions per Minute (RPM) at set Voltage and PWM (Encoder Setting = 45) Of DC motor with a 10cm wheel
Reasons:• Inconsistent power source• Lack of knowledge and understanding of
the DC motor’s behaviour
Future Work Implement and test the circuit
design Modification and improve design
(dependent on time) Communication of final design
Thesis Report Expo and poster
Knowledge Gaps: Implementing a PID Defining the boundaries of each training stage Weight of the overall system Alternate power source in order to keep motor
running consistantly
Engineering Design Process
Conclusion 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.