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Feb 2024
GOAL: convert rotational motion to linear motion through a system of linkages
SKILLS: CAD (Onshape), wood working, linkage design, wiring, prototyping, use of single board computer (Raspberry Pi), laser cutting, collaboration
The goal of this assignment is to replicate the motion of Mario (or another character) sliding down the flag pole at the end of every Super Mario Bros level.
Design Constraints
Design Constraints
the mechanism must have at least 3 moving linkages. Stationary/fixed linkages do not count.
Character must move in a vertical straight line for at least 10 cm.
May not use slots or tracks to keep the character in line.
Motion must be powered by a motor (i.e. can't rely on gravity to move the character).
Video
Video
Design Process
Design Process
One thing I really wanted to do was translate a full rotation to linear motion, since it is much simpler and would require less computational resources. There were many examples of translating a full rotation to an arc, and for translating an arc to linear motion so we decided to combine these to get directly from a full rotation to a line.
First, we made some mock ups out of cardboard and pins
Then, I made the parts in Onshape to validate the design. I first CADed the rotation to arc 3-bar linkage and the Peaucellier-Lipkin linkage (the diamond shaped one) separately. Then, I measured the angles at which the diamond linkage extends comfortably (doesn't overlap itself) and inserted the 3-bar linkage assembly such that the medium sized link of the 3-bar linkage lines up with the small link of the diamond linkage. To find the correct angle of the 3-bar linkage, I positioned it so it reaches the far point of the diamond linkage's rotation when fully extended, and reaches the close point of the diamond linkage's rotation when fully contracted.
Next, we cut out a mini version of the linkages and assembled it before finally cutting the full sized pieces and putting everything together.
Code
Code
CAD
CAD
Challenges
DC motors running at different Hertz
spacing out the linkages
gravity
Things to adjust in the future
Consider gravity more: the motor should got be so far above and off to the side because the torwue is uneven now
make the flag slide with the the pole to mimic how it is in the real game
If I were making this system without the design constraints of the assignment, I would've added a slider or magnet for extra stability
improve the stacking of the links to be more compact
move the center nail so it doesn't interfere
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