Integration Meetings | July 2020

July 1

Adrian Au SJ (Unlicensed) Micah Black Kristen Emiko Shiozaki (Deactivated) Michael Shiozaki Micah Bai

Array Panel Hinging

• Hinge design project was assigned today

• Initial thought was charging configuration would be sideways (side hinges)

  • Panels to move while charging - both the roof + trunk panels

• Assuming the panels have to stay on the car at some capacity, can we facilitate rotation for the trunk panel given what we’re hoping for our current trunk functionality (which is to act like a normal trunk)

• How important is angled incidence in the overall big picture (does it give us a 0.5% boost in overall day charging?)

  • Should do the math to determine the significance

  • In terms of high-level strategy, what are the aero / dynamic tradeoffs due to side hinges (if any)?

• 2 options being considered

  • Removing the roof & trunk panels and lay on ground for charging

  • Secure roof & trunk panels with hinges and change the angle of incidence of the trunk and roof panels (stays secured to the car)

• From a feasibility standpoint - the fewer hinges you have to make (especially consistency), the better

  • fewer panel gaps, etc.

• From a pure geometry standpoint, rear/trunk panel will want to hinge inwards vs. on the sides due to the hinge location being on a flat part vs. a curved part if it were hinged on the sides

• What is easier to design?

• Adrian recommends not following Minessota’s route - aka no hinges

• Space for trunk hinges - would it be wide enough for the trunk panel to open trunk style?

  • Might be able to attach to a chassis tube?

• Charging configurations are only practical if you have allocated charging times

• Ideal choice: remove trunk + roof panels for charging

• Rope Clarke + strategy in to learn about their charging models

• Are there any

Array Panel Cutouts

• Rough plan was to drill 3/4” holes where the terminals are such that the tabs poke through and solder through those

• Interiors would like to cover wires - don’t want to see any inside the car

• Goal for MPPT is to have all wires in 1 box

  • 2 wires from every electrical panel will run back to that box

• Would be good to have hole placements in CAD

  • Structures wants to know the general hole placements so that they can design around them for hinges and other projectd → Give structures the wiring diagram

July 22

Adrian Au Leif Blake Geoffrey Liu Micah Bai Kristen Emiko Shiozaki (Deactivated)

Brake routing between front and rear wheels

Concerns

• Where are we putting the cables

• How are we pulling the parking brake

• What mechanism fits best with our limited space
  (Adrian’s recommendation was a pedal style)

• Cable routing - will it interfere with other systems?

Old Routing

• Kevin’s feedback - Upright is okay but avoid making contact with the lower control arm

• Currently mounted to a par that has a lateral movement - maybe not the best place?

Why a Pedal Mount? Positioning?

• Pedal on left side of the car preferable for the driver’s left foot
  (not much room on the right, also makes more sense if it’s on the left)

What to sort out

• Placement of Parking Brake

  • Would be ideal to mount without extra tubes

  • Should be okay to mount to the firewall

  • Need to look into more about what we CAN mount too

  • Avoid using the release cable - poor UX and hard to generate enough force with the small lever

• Routing along chassis + through the interors (Dynamics)

  • Consider tension of the cable too - where you route it / how it acts on different parts of the car, may differ

  • Black-box approach - start with math calculations (to map out the tension in the cable needed)

    • correlation between tension in brake to squeezing in the caliper

  • Looked at the loading condition of the caliper before but there isn’t a spec (attempted DEA) - they assumed the friction force on the pads was basically negligible because the assumption is that the caliper does not require a lot of force to ‘activate' it

• Design of Pedal

Can we have a 3d printed part that the brake lines go through?

• Adhesives would be weak and cannot resist the pulling of the cable

• If we’re thinking of coming through a hole in the upright, the wheel wll turn a bit, but the push-rod does not turn and it’s hard to say how the cable will go through there

  • The bend radius of the cable kind follows the shape and goes around, but it’s hard to control the ‘motion’ of the cable
    (might be unable to prevent potential rubbing of the wheel)

  • For the actual brakes, might be better to come around the aerobody - current routing is going through a mess of components

Next Steps

• Routing through the chassis

• then work through components (mount to firewall, etc.)

• For brake route cabling going to the rear wheels - main ideal was to keep it in the bottom corner of the catamaran (by the driver’s right leg)

  • Might not need to go through the front firewall but will need to go through the rear firewall

  • For the front, cable routing should be similar

  • Understand what you can and can’t do from the Dynamics end (Geoffrey Liu to schedule another meeting w/ Leif)

  • Focus on routing first