Zero-Pilot 3.0 Project

Overview- Daniel Puratich (Unlicensed) Ethan Abraham Darwin Clark

ZeroPilot 3.0 ( ZP3 ) is our custom in house flight controller board! The project’s latest version can be found on our Altium 365, here. For access to WARG’s Altium 365, please message Daniel Puratich (Unlicensed).

The flight controller will have input interfaces from sensors, computer vision’s computer system, and our drone’s ground communication system. Zeropilot 3.0 will be able to output control signals to all flight control surfaces aka motors/servos on the UAS (unmanned aerial system). The board will use a microcontroller which firmware will use to execute our flight logic.

Weekly architecture meeting have been held in late May and early June to make major decisions with the firmware team, see here for notes. Overall the project has been broken down into five sections designed for ownership by one or a small group of electrical members. These sections are defined below along with their owners.

For all custom EE flight hardware, including ZP3: mounting holes should be 3.400mm and with 6.000mm plating, electrically not connected.

Power Distribution Architecture

Research Topics

Centralized vs. Split Power Distribution Architecture

• Research advantages and disadvantages of a centralized power distribution architecture versus a split power distribution architecture with multiple duplicated voltage rails (5V, 12V, 24V, etc.)

Buck Converter or Buck Boost Converter. What about Buck-Boost Converters?

• Research advantages and disadvantages between using a buck converter versus a boost converter to generate a desired voltage rail (Ex. if I need to make a low power consumption rail of 24V, and I have both a 12V and a 50V rail, should I use a buck converter to step down 50V to 24V? Or, should I use a boost converter to step up 12V to 24V?

• In what applications should we use buck-boost converters?

Buck Converter Sourcing

• Research a list of manufacturers, suppliers with available in stock buck converter ICs

Optional Current Sense Interface

• Should the connector interface for optional current sense of the voltage regulator buck converter PCB modules be V_sense+ and V_sense-, or I_sense and GND? That is, should the buck converter PCBs send the raw Kelvin-sensed signals to a connector, or should the PCBs have a dedicated current sense amplifier from which the output and GND is sent to a connector?

Buck Converter Projects

12V-5V @ 3A Buck Converter Board - Nolan Haines Neel Bullywon

• 12V-5V Synchronous Buck Converter PCB @ 3A Max Load Current Consumption (15W)

• I/O:

  • Input Voltage Connector

    • +12V

    • GND

  • Output Voltage Connectors (2x)

    • +5V

    • GND

  • Current Sense Connector

    • V_sense+ and V_sense-, or:

    • I_sense and GND

• Features:

  • 12V-5V Buck Converter @ 3A

  • Reverse Polarity Protection

  • Status LEDs for both +12V and +5V voltage rails

  • Optional current sense interface

• Dimensions:

  • 15mm x 25mm

  • No vertical design constraints

24V-12V @ 2A Buck Converter Board - Michael Botros

• 24V-12V Synchronous Buck Converter PCB @ 2A Max Load Current Consumption (24W)

• I/O:

  • Input Voltage Connector

    • +24V

    • GND

  • Output Voltage Connectors (3x)

    • +12V

    • GND

  • Current Sense Connector

    • V_sense+ and V_sense-, or:

    • I_sense and GND

• Features:

  • 24V-12V Buck Converter @ 2A

  • Reverse Polarity Protection

    • Determine for given PMOS selection if conduction power loss is acceptable. If unacceptable, consult your leads to discuss compromising solutions

  • Status LEDs for both +24V and +12V voltage rails

  • Optional current sense interface

  • Should also be able to provide 5V @ 3A with the change of a few passives

    • This “requirement” is optional depending on the difficulty level we’re looking for. It would be useful for the use case of the PCBA, but it increase project difficulty.

• Dimensions:

  • 20mm x 30mm

  • No vertical design constraints

50V-24V @2A Buck Converter Board - (Unasigned)

• (12S) 50V-24V Synchronous Buck Converter PCB @2A Max Load Current Consumption (48W)

• I/O:

  • Input Voltage Connector

    • (12S) +36V to +50.4V

    • GND

  • Output Voltage Connector (3x)

    • +24V

    • GND

  • Current Sense Connector

    • V_sense+ and V_sense-, or:

    • I_sense and GND

• Features:

  • 50V-24V Buck Converter @ 2A

  • Status LEDs for both +50V and +24V voltage rails

  • Optional current sense interface

  • Should also be able to provide 12V @ 2A if needed with the change of a few passives

• Dimensions:

  • 25mm x 35mm

  • No vertical design constraints

+5V USB - 24V @0.25A Boost Converter PCB - Steven Wang

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Boost Converter PCB !

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Output Voltage

• Adjustable to these standard voltages:

  • 5V

  • 12V

  • 18V

  • 24V

• Allowing for voltages in between is fine, but getting to these values would be nice!

...

Output Current

• Targeting 0.25A Output minimum at all adjustable voltage values

  • The highest minimum output power of which will be 24V*0.25A=6W

• Being able to handle higher output current than this is absolutely fine under the requirement that it doesn’t vastly increase cost or development time.

...

Efficiency

• The use case for this board is take output from a 120VAC Single Phase to 5V USB standard power converter and use that output as the input to this board

• Looking at a standard wall adapter I see they can do 1-2.5 A of output current at 5V so with some basic math, 24V*0.25A=6W & 1A*5V=5W, so efficiency is a concern in this case

• Anything above 80% efficiency will work for us, but the higher the better for our use case!

• Previously using a synchronous buck converter was considered imperative due to efficiency concerns, but a decision matrix should be used to evaluate it’s necessity vs cost.

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Cost

• We don’t want cost to gate this project’s progress. Evaluate efficiency and difficulty vs cost via decision matrixes!

• There are no hard requirements.

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Timeline

• In order for this board to be most useful we would like it all debugged and functional before competition in May 2023 such that it can be utilized for debugging at that time.

• Beyond that soft requirement it is entirely up to you. Once the Asana is back, we will utilize that to track progress.

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Input Output Connectors:

• Vin

  • Take a pick of USB-C or whatever other standard USB you want.

  • Only need +5V and GND pins, (presumably no ERC +D and -D pins)

• Vout

  • XT60PW-F

  • PWR and GND

Other Features:

...

Status LEDs for both Vin and Vout voltage rails

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Since the output voltage is adjustable, an LED indication to the user roughly where their output voltage is would be nice.

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Introduction

Subpages ordered based on priority for team.

Purpose

The purpose of each subpage here is to that for every project its nice to have a centralized confluence doc that contains all the info about the project such that the project is easy to explain to anyone. We do this in the EE confluence space under active projects (subpages of this page), an example would be RPi Interface .

For all new projects, especially ones in early stages where ideas fun rampant, leads should create a project page for the project. The idea is long term anyone contributing to this project updates the doc then it ends up looking like Servo Module 12S down the line with lots of design info within.

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