Taking apart the bike, removed all parts except chain and cog

Create rough drawings

Start CAD for iteration 2 prototype

Meeting with advisors

• Try to finish CAD by end of week (Jan.19.19)
• Try to finish mechanical design and machining by end of month (Jan.31.19)
• Leave February for testing and check if another prototype is needed
• Finish scoping parts for Electrical and Software aspects by end of next week Jan.25.19
• Finish electrical design by end of month (Jan.31.19)
• Check up with advisors weekly and make sure mechanical design doesn’t have any major flaws

Taking apart the bike:

• Removed wheels
• Removed pedals
• Removed freewheel

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Need to remove:

• Cogs from freewheel
• Pedal shaft

Purchased a used bike!

Assembling our Prototype

Today we put together the prototype we laser cut out of acrylic

The biggest takeaways from this were:

• Need to stabilize the two circles
• Smoothen the path of the expanding pieces (perhaps add a third track)
• Figure out way to keep pieces assembled permanently
  • Current (temporary) method doesn’t work as bolts/nuts keep falling off

We are a group of Mechatronics Engineering Students at the University of Waterloo. The team is composed of Ganan Prabaharan, Octavio Harris, Nikhil Boddhu and Po Jung Chen.

Our goal is to prove the feasibility of continuously variable transmission (CVT) on bicycles. CVT allows bikers to choose from a continuous range of gear ratios. Taking advantage of this feature, we also wish to add automatic transmission to help bikers maintain their desired cadence.

For our project we wish to design and create a proof of concept solution that will showcase CVT on a bike, while also having the capabilities to automatically shift gears so that the cadence matches a desired value.

From our design process we have narrowed down our solution to an expanding gear mechanism.

Using a motor and some speed sensors, we plan on actuating the gear mechanism to help the biker maintain their bike cadence even as they increase the linear speed of the bike.