Week 3

Introduction

Project Goals

Construct a go-kart frame
Create a functioning ESC/motor controller
Create a functional electrical system
Integrate all systems into a full go-kart

Build Stage: Preliminary Fabrication

Go-Kart CAD design
PVC-pipe frame (preliminary design)
ESC design
ESC preliminary build

Progress Summary

Design

Mounted components
- Motor
- Seat
- Pedal

Electrical

Rerouted and redesigned PCB design (more streamlined traces)

Fabrication

Mounted gas pedal
Mounted motor and began chain work

Testing

Mounted motor
Aligned chain

Problem Solving

Motor misaligned
- - Print mounting block to shift it forward and realign
- Chain isn't tensioned properly
  - Find chain with masterlink and remove excess links with chainbreaker. There is no chainbreaker in shop, so one was ordered this week

Note: This week, we couldn't use the shop because we didn't have supervision, so we focused on mounting 3dp components we already had.

Pedal mounted at the front

Seat mounted on back panel

Go-Kart Reference CAD

Challenges and Solutions

Back view of sprocket aligned

Motor Mounting

Problem: The pinion sprocket isn't axially aligned with the axle sprocket. There is also no space on the panel to move the motor forward.

Solution: 3dp a block that mounts to the original motor slots, and has additional slots for the motor to mount to.

Chain Tensioning

Problem: #35 chain doesn't fit on our sprocket, assumably because it was from a Chinese manufacturer that doesn't standardize to imperial

Solution: Take the chain from a cart from last year

Problem: Chain isn't tensioned properly

Solution: Use chainbreaker to resize chain

Problem: We have no chainbreaker

Solution: Ask to buy chainbreaker

Top view of sprockets with motor block

ESC

Problem: PCB wiring is too messy; power traces are not thick enough for 20A; Back-EMF for power traces will interfere with logic lines.

Solution: Reroute the PCB trace lines to accommodate for the high power back-EMF. Increase trace width to compensate for the high current lines, and isolate these lines to avoid back-EMF logic.

Work Ethic and Collaboration

For our Go-Kart project, we thought it would be best that we split up the necessary work by our respective interests.

Charlie is in charge of designing and building an ESC with Hunter. He has finished his preliminary PCB for a hand sized BLDC and has ordered it from PCBway. When it gets here, he will solder SMDs.

Tyler is in charge of the CAD of the Go-Kart. This week, the main chassis was finished and all that remains is printing mounts for components like the brake. This work will be split up between all three of us.

Tyler and Hunter are the ones most primarily working on the fabrication of the Go-Kart. This week, we used calipers and pliers to measure the chain. We also used the 3dp to make the mounting block for our motor.

Next Steps

While the first iteration of the PVC pipe frame is relatively complete, we still need to mount components. This will require some creativity with 3d prints and adjustable mounting blocks so that we don't have to have our dimensions exactly right.

Next Cycle Goals

Fabricate steering assembly
Align steering
Mount brakes

Timeline

By next cycle:

Mount front wheels and steering
Mount brakes

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