2021-11-11 Meeting Minutes - Drivetrain

15 Days until Final Design Review...unless,..

Goals

  • Review next steps post Ping's feedback
  • Confirm Drivetrain design with the rest of the team, see if we're missing any requirements
  • Touchbase with rest of Drivetrain team/stakeholders. Review timelines

Action Items

  • Wheel integration!!!
    • To do ASAP!
      • Get more detail on the inner fillet of the wheel so that we have more information on the constraining area
      • Print the current wheel hub and test ASAP 
      • Consider alternative methods, such as adapting the original hub → Asha Mills Emmett
  • Prototype bonding aluminum hubs to the carbon fibre
    • Verify choice of epoxy
    • Verify successful establishment of the bond gap between the aluminum and carbon fibre
    • Verify by testing the strength of the carbon fibre assembly after bonding using the Department's equipment
    • To do ASAP!: 
      • Buy bonding materials from Composites Canada
      • Get a cap machined
        • Add bonding step 
      • Develop a test plan and establish what we are specifically looking for (Instron?)
    • Questions:
      • How much material do we have left? → Chanpakorn Chaiklahan
      • Approximately 3 ft., enough for another test.
  • FEA!!! → Andrew Tersigni (Deactivated)
  • Smaller CAD updates
    • Refer to the review's meeting minutes for specific feedback on each sub-system
    • General feedback:
      • Reduce the amount of hardware needed → PEM nuts, flange bolts, reduce overkill of mounting locations, remove unnecessary 3D printed parts
      • Reduce areas of stress concentration!
      • Verify machinability with Demtool's guidelines

Lower Priority

  • Bill of Materials!!! Confirm what components are getting sponsored, confirm that items don't have ridiculous lead times, pricing, etc.
    • Do in a separate excel file for now...need to touch base with Ethan about his doc
  • CF assembly jig → Max Apitz-Grossman
    • Just come up with a plan for now. Design and a more detailed plan for this can be delayed till after exams
  • Treads
    • Lower priority? Can also be delayed until after the design is finalized, just account for some space in height/width, etc.

Updates

MemberUpdateAction Items
Former user (Deleted) (Chassis)
  • Focus on FEA!
  • Add Vector NAV IMU, with bonus two antennas
    • Verify with Melvin
  • Battery mount, E-Stop, LED Matrix
  • Extend chassis back to prototype length
Former user (Deleted) (Wheel connections)

Emily Adam (Differential bar)
  • Acquire bonding materials & Composites Canada order
  • Wheel hub test print, try to break
  • Send actuator details
  • Help with SolidWorks sim → what do we isolate for sims?
Former user (Deleted) (Frame/structure)
  • Correct suspension geometry to match prototype
    • Note that Asha's piece is subject to change
Former user (Deleted)
  • This weekend: measure inner fillet of the tire, update wheel CAD
    • Look at using "Loft" in SolidWorks to create the fillet

Full Drivetrain Team Discussion -- Notes

  1. Walk team through the Drivetrain CAD → can show slides
  2. Current length, width, height values
    • Length: 1.5 m
      • When corrected, give numbers to Orson!!!!
    • Width: 1.18 m
    • Height: 0.92 m
  3. Current mass = ~26.5 kg
    • Chassis = 8.07 kg
    • Suspension (1.78 kg) * 2 = 3.56 kg
    • Differential = 1.0 kg
    •  [ Wheels (1.32 kg) + Nanotec Motor (0.64 kg) + VersaPlanetary (0.34 kg) ] * 6 = 13.8 kg
  4. Current distance from mounting to the ground = ~530mm
    • Arm was estimating 350mm → reconfirm that geometry matches the prototype
  5. Current height of Gimbal stand = ~940mm
  6. DIstance from plate to end of the rover = 0.4m


Questions...

  • When does SW want to claim the prototype? How long do you plan to use it for?

Notes...

  • Consider routing and separation of signal/power, shielding
    • Create two channels, specifically for encoder
  • Confirm E-Box plan with Ethan → who's taking it over, do we know?
  • Manufacturing timeline.........discuss
  • Fear bushes (protect wires!)
  • Revisit gearbox loading and bending
    • Backup suspension plan
  • Moment calculations arm → statically will it tip? Moment at which it will tip?
    • Note: some missions are without mechanism
  • Consider the fact that we need some slip with our front/rear wheels for turning
    • Tread on all wheels versus some
  • Contact with less wheels (4 versus 6)

New Tasks

General Notes