The Marching Illini
IDEATION
Bringing the Tenants of Design Thinking into Classical Mechanical Design
STAGE ONE
The People: Empathize and Define
USER GROUP
List of Needs and Insights for Elementary School Students:
Basic understanding of the mechanism with partial unknowns
A sense of wonder is the mmachine
Avoid scary and creepy traits
Give a sense of familiarity, make it something that relates to their basic lives without being too specific, avoid pop culture
Make it bright or colorful to catch and keep their attention
There is a large age range for elementary students so it cannot seem too “kiddy,” but also not overly complex so that it is entirely beyond the realm of understanding for a 1st grader
It needs to be user friendly and have an obvious method of operation, without giving away exactly how it works
They should be motivated to learn something new because they found something cool that that do not understand
Getting into the mind of an elementary school student at Engineering Open house, they may:
Say
“That’s scary”
“What is this?”
“How does that work?”
Do
Touch it
Watch others operate it
Turn the crank the wrong way
Stand on tip-toes to reach/operate
Think
“Is this what college students do?”
“What is this made out of?”
“How long did it take for them to make this?”
“I want to make something like that!”
Feel
Inspired to read/learn more about automation
Curious about mechanisms
Excited about something new
Scared of realism
Perplexed/intrigued about what engineers do
POINT OF VIEW STATEMENT
Elementary school students need a way to be engaged and inspired while having fun. Unexpectedly, in their world, they are not exposed to many interesting or complex applications of theory.
"HOW MIGHT WE..."
How might we attract them to our prototype?
How might we explain the mechanism?
How might we inspire them/ make them want to learn more?
How might we connect this to engineering/exemplify what engineering is?
How might we not scare them?
How might we get them to successfully operate the mechanism?
How might we give them a meaningful takeaway (be able to explain/remember)?
How might we challenge them?
STAGE TWO
The Design: Ideate and Prototype
LEG MECHANISM
Klann Linkage with Triangle Base
Advantages
Three wheels are easy to hide under the automata’s drums and in its body
Narrower frame in back allows for a more proper width person
Slightly smaller mechanism with less motion near the crank, makes it more compact
Klann linkage has a high vertical foot pick-up which will help get out of tall grass
Good balance of fast walking speed and smooth ground contact
Disadvantages
Linkage has less contact time with the ground hurting stability
The linkage motion seems less human
Three wheels may lead to a less stable motion
Challenges
Making a place for the battery in a narrow back frame
Promoting stability with only three legs
Getting reliable stability from a linkage with a short contact point
MATERIALS
Laser Cut Delrin:
Advantages:
durable
fast to make parts
good tolerances
Weaknesses:
not as versatile
limited color options
Laser Cut Acrylic:
Advantages:
aesthetic (clear) appearance
fast to make parts
good tolerances
Weaknesses:
very brittle
not as versatile
costly material
no color options
3D Printed Parts (PVA):
Advantages:
versatile (many design options)
many color options
Weaknesses:
Long print time
Inexpensive
Poor tolerances
Support material that requires removal
Melts easily
It was concluded that all laser cut parts would be changed to delrin for the final prototype because durability is the most important factor in this design. 3D printed parts are used where laser cutting designs is not realistic.
ARM MECHANISM
The inspiration was drawn from a piano and a music box. The original lo-fi prototype had a cam on a shaft similar to the nodes on a music box shaft, and these pressed down on a lever mechanism that hit the drum in a manner which was inspired by the way a piano hammer hits the strings.
STAGE THREE
The Results: Test and Iterate
TESTING AND ITERATION #1
The first prototype was produced for Engineering Open house. Not much major iteration had to be done because with low-fidelity prototyping, small changes can be made along the way to make the design work. After two days of being used by elementary school children, the prototype was fairly worn down and parts were broken, and the team recognized that using bolts and nuts as joints was not a good option unless they could be glued so that they would not unscrew during use. Also the use of a balloon for the character's head was not the best because it leaked air and resulted in a deflated head by the end of the open house.
TESTING AND ITERATION #2
The next prototype was for the full walker design, and it was made using a clear acrylic chassis. It was very apparent after assembly that the acrylic was not durable enough, and it began to crack at high stress locations and became easily misaligned. There was also no good mount for the motor or battery, and there was a lot of hot glue used to fuse components. It became apparent that this was not a sturdy enough design to hold up to the performance requirements.
TESTING AND ITERATION #3
The third iteration featured a 3D printed base with delrin chassis frame, but the alignment was off, and the base needed to be adjusted. The shoes were also very large and the team realized they needed to be redesgned for the next prototype.
TESTING AND ITERATION #4
The fourth prototype was the one that finally walked! The drummer featured a new chassis base and new shoes that all aligned and worked well. The team brought him out to the grass and sidewalk to test him out, and with one final iteration (shoe change), he was good to go for competition. He was decorated that night and came alive and ready for his photoshoot and video demonstration the next day.
"it's brilliant, just brilliant"
Prof. Liebenberg