2021-10-24 Meeting Minutes - Drivetrain

Owned by
Emily Adam
Oct 29, 2021
2 min read

CDR (Final Design) Meeting November 18th → 25 DAYS

Goals

  • Review subsystem designs

  • Talk about the next steps

    • CAD integration plan, best approaches?

      • Do it in stages?

    • Mentor feedback meeting

CAD Spins

Chassis

Notes:

  • Current mass:  5.7 kg**

    • Missing mounting plates

  • Increase strength of 3d printed shelf connector

    • Currently looks like it would snap from side to side movement

    • Consider mounting to upper clamping block (around rocker beam), then extending the block's width to mount elsewhere

    • Or consider switching 3d printed system to: 3d printed part as the easy mounting interface, then having aluminum gussets/blocks to handle the fastening load

      • Reference Austin's prototype arm joint

  • Go with single connector for tubes as used in last week's iteration

    • Consider adding a divider to locate the beams for assembly? Or verify that boring bar on lathe is deep enough to bore through

  • Increase elevation of rocker beam

  • Consider switching current clamping set-up of rocker beam to clamping downwards, pillow block style

  • Verify CF tube will fit with a bearing, check out SKF

    • Consider an aluminum sleeve to interface from CF to bearing

  • To discuss with Austin: mounting scheme

Suspension/Legs

Notes:

  • Current mass: 1.6 kg per suspension

  • For connector pieces, add clearance between outer faces so that locating step and locating stud are the only surfaces making contact

  • Undercut radius of male to get rid of the edge

  • Swap rocker bushing to bearing

    • Can keep bogie bushings. Avoid machining down the flange, lmao

    • Call out bogie connector for a smooth surface finish since rubbing against bushing

  • Swap shaft collars for something more sturdy, like retaining rings or thread the shaft and secure with a nut

  • Add differential mounting surface

Wheel connections

Notes:

  • Current mass: ~1.3 kg for designed components

  • Avoid cutting the motor...

    • Change inner ridge of the wheel hub close to the gearbox end. 3D print prototype and test on wheel

  • Add bearing after the gearbox to increase wheel support and load-bearing

  • Remove additional flange underneath corner brackets

  • Verify encoder height → swap to 22mm encoder

Differential bar

Notes:

  • Current mass: 1.0 kg

  • Preload fasteners, swap socket head on C-Channel to cap or hex head 

  • Make sure blocks can slip over lol

    • Delrin can be picked up from EMS

  • Consider easy adjusting of length of eye joint

    • Will require different pieces

  • Remove locating dowels

  • Add anti-canterlever 

  • Consider twisting and digging of plates into acetal, increase it's width

  • Thread eye joints into a mill component rather than have a nut

  • Increase thickness around bushings

  • Add spacer between bushings

Update & Action Items

Member

Update

Action Items

Member

Update

Action Items

Unknown User (a4tersig@uwaterloo.ca) (Chassis)





Unknown User (amillsem@uwaterloo.ca)

 (Wheel connections)





Unknown User (cchaikla@uwaterloo.ca)





Unknown User (e2adam@uwaterloo.ca) (Differential bar)

  • Bought CF tube! Is sitting in the bay

  • Quickly set-up the prototype for SW to test with now

  • Confirmed encoders with Cindy, Melvin, and Farris & vendor. Ready to order

  • Order encoders and missing VP ratios

    • Since we're taking off the wheels from the prototype, we should just steal the gearboxes too imo

Unknown User (mapitzgr@uwaterloo.ca) (Frame/structure)

  • Add differential mounting for Emily to edit



Unknown User (tvaler@uwaterloo.ca)

 







New Tasks

  • CF tube analysis

    • Verify if tube has tolerance from 32 mm diameter with its surface finish

  • Check 2019 drivetrain for chassis-suspension weight ratio

General Notes