Milestone 3

A major part of our progress constitutes the building of the “parallelogram mechanism”. This refers to the steering structure at the front of the vehicle, which allows the wheels to tilt around bends with all wheels on the ground. This mechanism makes use of 6 half-inch ball bearings and 2 five-eighth-inch ball bearings. The prototype is pretty sweet! Check out this video: 

 

 

  • Geometry choice: So far, we have just made a prototype of the steering mechanism. The reason why our design is a parallelogram is because we thought is the most apt geometry to utilize steering via tilting.
  • Interface between parts: Today we thought deeper about how axel of wheel is to be joined to vehicle. Our prototype revealed some structural weaknesses in the initial design of our steering mechanism, thus we had to think deeper about the way in which this was connected. In the end, we chose the box joint to change the interface plane by 90degrees while maintaining structural rigidity
  • Manufacturing methods: Currently, we are making a prototype by laser-cutting wood. However, our final vehicle will use water-jetted aluminum sheets as this would ensure that they are a lot stronger.

 Screenshot of our CAD render:Image

 

Our component choices have not differed much since Milestone 2:

  • The SK3 motor was chosen, as it is a brushless motor that fit our budget. We chose the brushless motor for its power over its brushed counterpart. We are also purchasing $3.99 brake pads to make a custom brake mechanism, which will work together with the 65” brake cable we want to buy. We learned that a longer brake cable can always be shortened, but a brake cable that is too short would be useless!
  • Appropriate wheels are really hard to find! We settled with 10”x2” side mount wheels – decently size for its price. Based on calculation, our optimal size of wheel was 14”, but we decided to work with 10” as it is the largest (affordable) side-mount wheel we could find.
  • For now, we are using the provided 80/20 and aluminum plates to create the frame. Our strategy is first to purchase the major hardware, and then to make the frame around it. This would ensure that the spatial arrangement of each part does not clash with another.

So far, our prototype has revealed much about our preliminary design of the gold-kart. We received a comment that we can potentially include a torsion spring in our parallelogram so that the vehicle’s natural state is upright and not slanting to one side, which will make tilting smoother. We’re tweaking the joints and fastening methods along the way; for example – we want to decrease the width of the kart by another 15cm by changing the length of the parallelogram mechanism. We’re excited for the weeks to come!

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