Joe Kinsella July 3, 2021

https://www.linkedin.com/in/joseph-kinsella-677172b4/

Joe Kinsella is a UW alumni who is the CTO of Pegasus Aeronautics.

• Why does Pegasus Aeronautics focus on hybrid drones?

  • Longer flight times

  • Consider generator + fuel weight (8x more energy than battery)

  • Industrial Drone Companies: Avartek, BFD, Alta, Infinite Jib, Disco Geo, FoxTech

• What batteries does Pegasus use?

  • Used 2 COTS batteries in series

  • Industrial drones are larger and have less space constraints compared to compact drones like DJI

• Does Pegasus use a battery management system (BMS)

  • No

  • Working on one → At least BMS will report issues with batteries (report state of charge)

  • Don’t know if one cell is too far down? Assumption is that system is kept at 90% charge all the time

    • Battery is a buffer for generator

    • Batteries never fully charge or never fully discharge

• Generator

  • Use as a motor to drive the engine, start the engine

    • Starting the engine was when the most torque was required for the system

    • This is where they thought they needed hall effect sensors

  • Then operate as an actual generator to generate power

  • ^ This is a software change, seamless, no state change

  • FOC is the only option for Pegasus (also Diode rectifier to convert AC from generator to DC exists)

• BLDC motor

  • Recommend doing custom ESCs

  • May seem intimidating, lots of small things to remember (small layout decisions can impact performance, overshoot, noise, ripple current thru caps, power rating of MOSFETs kinda need to guess based on how you’re using (how fast you can get heat away) ) →

  • Pegasus uses Texas Instruments InstaSPIN motor control solutions: https://www.ti.com/microcontrollers-mcus-processors/microcontrollers/c2000-real-time-control-mcus/applications/instaspin.html

  • Look into open source designs: ODrive (form factor not great), VESC (last updated in 2018)

  • Look into sensorless design (no hall effect sensor or encoders for commutation)

• Industry uses Pixhawk/Ardupilot

• Radio system

  • OpenHD which is opensource

    • Attempts to recreate DJI FOV

    • https://openhd.gitbook.io/open-hd/

    • Uses WiFi

• Use PCB to cut down on clutter of wires!

• Lookin thru connectors is never ending but use JST series or some other connector rather than headers

  • Get concrete specs for wiring

  • Then you can confidently choose connectors, connections etc.

  • Spring contact connector → work but

  • Ring terminals → force of a bolt holding it in, better for unplugging often vs

  • Molex, Nicomatic, power pole, XT60s

  • Molex MultiCat for motor connections on Pegasus (maybe more than we need) but good connectors

• Multiconductor for multiple signals

• Using CAN (UAV CAN https://uavcan.org/ ?)

  • Recommended

  • not a substantial amount of data passed

  • more for state of diff modules

  • UAV CAN → lots of implementation of functions if its custom hardware

• How many PCBs are in Pegasus' electronics system?

  • Fuel Pump Controllers (in and out?)

  • Generator controller

  • Cooing pump controller

  • Power Engine (multiconductor)

  • CDI Board (used to control spark plugs)

  • USB to CAN converter board (for customers to flash)

  • About 8-10 PCBs per system

    • Is it worth combining PCBs? Space, cost maybe etc.

  • Peripheral Bus

    • 24V from the 12s

      • fuel pump, cooling pump (takes the most power 24W), fan control module (turns of radiator fan) cpu rad

      • tsc micro pumps

    • 12V rails for fuel injector, CDI