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Competition Year

2022-2023 Aerial Evolution of Canada Student Competition

Team

Waterloo Aerial Robotics Group

Architect(s)

Anthony Luo

Status

Status
colourGreen
titleV1.2V2.0
- Final competition hardware list

Last date updated

15 Feb - ZP-CV communication and CV search referenceAirside Power Architecture with Specific Rails and Limits

On this page

Table of Contents
minLevel1
maxLevel5

...

[OSD] - on screen display (attitude information overlayed over video feed

[MUX] - Video Mux

[rfd900x] - RFDesign RFD900x Modem (singular)https://uwarg-docs.atlassian.net/l/cp/LPn8hwCv

...

[Competition Requirements] [CR]Competition Requirements

[VN-300] [VectorNav VN-300] 2023-03-26 - VN-300 Rugged Harness

📐 Architecture

...

The architecture of a drone can be found in the [Competition Design Outline]. <# iterations> iterations of the drone will be created, at <#milestones>. <# final copies> of the drone will be created in “competition spec”. Our system will meet the requirements in [Competition Requirements].

Our general architecture has the following hardware elements:

Airside Components:

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All components marked “Optional” will not be present for the May 2023 Competition

  • Airframe (Wings, Fueselage, tail)

Power:

Propulsion:

Compute

Mandatory:

Optional:

Airside Peripherals:

Peripherals

Mandatory

Antennas

2 900 mhz antennas

...

could be linear if we use yagi (might be better for signalqualiy idk)

...

Optional

Groundside Components:

Infra Components

  • Tuning Rig

    • ready for comp drone.

  • Groundstation

    • ready by mid january

Airside Architecture

Now that we know what components are going on our drone, let’s talk about how they’re going to be laid out on the drone itself. This page will be finalized on Nov 6, 2022. After that date, any changes must go through a formal RFC process involving all subteam leads.

Airside Hardware Layout

The plane will be comprised of 5 main sections: the fuselage, cabin, avionics compartment, wings, and tail. The avionics + passenger compartment will be part of the main fuselage, while the wings & tail will house more electronics.

...

Batteries & Power Distribution

Batteries and Power Distribution shall be mounted in front of the passenger compartment, under the same access lid as the pixhawk & various other PDB/Sensors. This should make wiring easy, and make weather proofing easy. Batteries & battery mounting to be decided.

The battery box should be easily accessible from the top so that battery swaps may be easily accomplished during task #2, and should be weatherproof and house the PDB, Batteries, and necessary power connectors in an manner that makes upkeep & plugging/unplugging/probing connectors easily.

Avionics Compartment

The avionics compartment will house all the airside compute. The compartment should be weather sealed, but be mounted on the drone in a way such that all electronics are easily accessible and serviceable with minimal effort (ideally no screws removed to plug/unplug connectors from any of the onboard computers.

The avionics compartment should allow for airflow and cooling that can be shut (either manually or automatically) in inclement weather.

Sensors may be placed in the avionics compartment, but they should be mounted where they make sense. See below

Wings & Tail & Fuselage & Peripheral Mounting

The wings and the tail will house a lot of the RF Communication modules, such as the VN-300, rfd900 antennas, VTX antennas, and any GPS modules.

Transmitters

Both transmitters (RFD900, 1.3ghz VTX), should be placed in areas with adequate cooling/airflow. They are not weatherproofed, but do tend to be cooled passively by air moving across their heatsinks. In ground ops mode, it may be necessary to actively cool the devices over extended periods of time, especially if transmit power is high.

Cameras

There will be two pilot cameras. Both should offer +/- 10-30 degrees of adjustment. One will be mounted forward-facing, while the other will be mounted downard-facing. Both will feed into a video mux switch which then feeds into an OSD, before feeding to the VTX.

Sensors

The VN-300 receiver (red box) should be placed as close to the center of mass of the plane as possible, with the axis aligned (x is forward, refer to ZPSW Documentation for more detail). This can be done above or below the passenger compartment, but should be in a weatherproofed section of the plane.

Both VN-300 receptors & their grounding planes should be placed 1M apart, facing directly upwards, above other elements. These will be mounted inside the wings. The vn-300 is not weather rated, and should be protected.

NEO M.8 GPS Modules should be placed facing upwards, on the wings away from other soures of RF transmission. We anticipate having one for ardupilot, and one from the competition organizers.

Airspeed sensors should be placed in clean air, facing forwards.

Optical flow sensors & rangefinders or lidars should be mounted at the bottom of the drone, in our sensor cluster.

Antennas

The RFD900x Antennas should be placed 90 degrees apart from each other. There is no distance separation requirement. The RFD900X transmitter itself should be placed somewhere with adequate airflow.

The VTX Antenna should be placed as far as possible from other sources of RF interference (such as other antennas, sensors, or ESC’s). At the moment, the plan is to place the singularity 1280 on the tail of the drone.. The VTX transmitter itself should be placed somewhere with adequate airflow.

Cameras will be mounted outside the fuselage, one pilot cam forwards, one pilot cam downwards, one CV cam downwards. The pilot cameras will feed into a 2-1 mux switch controlled by ZP before feeding into the VTX.

Motors

Motor controller placement is decided by Mech, in a way such that the push prop ESC has adequate airflow, and the quad ESC’s have airflow when in use and are otherwise hidden.

Servos can be placed at the discretion of the mechanical team, provided the servos are equally balanced and symmetrical along both sides (within a few mm of error).

Airside Electrical Layout

Please see 2023-03-07 - Clarity on Electrical Components on Comp Frame . EE Team member to update with more specifics Daniel Puratich

Power Architecture

The drone will run a 12S power system.

  • VBatt Dirty (For ESC’s)

  • 12V Dirty (For Flight Controllers & Jetson)

  • 5V Dirty (for servos, LED’s, etc)

  • 5V Clean (for VTX, Sensors, etc).

All dirty power rails will be broken out from the flight battery using a PDB (i’m a fan of this one if we need a COTS PDB) , while the clean power rail will be broken out of the 3s battery.

Wiring

All of the wires for the sensors will be pre-run through the frame in dedicated channels, with connectors left exposed near the sensor compartments and the avionics compartment. This means that any time a sensor needs to be replaced, we do not need to re-wire the entire sensor. this also means that when we need to re-wire the flight computers, we can use the cables that are already connected to the interface connectors an simply plug in a few large connector banks to our dev interfaces. Running more cables through the channels should be supported, but all necessary cables should hopefully be routed during assembly (or when it is easiest).

All sensors shall be connected to the respective device owners listed in the hardware components section. There will also need to be a single UART connection between ZP ↔︎ Jetson, as well as multiple (at least 5) communication wires available between the PX5 and ZPHW.

Connector Standardization

  • Gender Decoding

    • Gender conventions regarding what goes where are defined below.

    • Gender is defined by the metal conductors in all cases. Plastic housing should be ignored when deciphering gender. The manufacturer’s dictated gender decision takes preference over this, however, it will be clearly iterated here if that is the case.

  • XT series connectors are convenient, common in the hobby world, fairly reliable, and relatively cheap and will therefore be employed for all WARG DC power connections whenever possible.

    • COTS PCBAs after require solder pad connections which we will accommodate, but breakout to our prioritized connectors whenever possible.

  • XT60 connectors will be prioritized for any sub 150 A pulsed DC connection

    • For ESCs and anything smaller this should be prioritized

    • XT60-F is on batteries and so the XT60-F should be used on any voltage source and XT60-M should be used on any load. This gender convention is also used in the COTS world and keeps things simple.

      • Manufacturer PN Gender: “-F” is female & “-M” is male

    • Custom hardware will use XT60PW series connectors and follow the above gender convention.

  • XT30s will be avoided when possible for simplicity

    • While XT30s are smaller and meet our current requirements for lots of low voltage loads in order to minimize the amount of connectors we need to stock and use XT30s will not be prioritized when an XT60 can be used.

    • COTS loads and sources with XT30s will be adapted to XT60 through harnessing

  • XT90 connectors will be used for any greater than 150 A pulsed DC connections

    • COTS higher current 6S and above batteries often ship with these XT90s and so we will accommodate such a design decision as they are rated for the higher current.

    • Anti-spark XT90s should be used whenever possible to limit sparks from in-rush condition though this may not always be possible.

    • XT90 battery input splitting into ESC and converter connections should be done on a properly specified PCB with XT connections done in harnessing.

  • AC Mains is not used on any WARG aircraft and therefore a connector will not be specified

    • No voltage sources exceeding 55 V during nominal continuous operation are to be present on aircraft due to a lack of necessity and safety concerns

  • ESC BLDC Motor Controller Phase connectors will be specified in the future and require more decisions in the future.

    • 3.5mm banana connections is a solid option from the hobby world, but they can be a pain. Other size banana connections may be used as well on smaller aircraft as we come up with more specific decisions.

      • Gender Convention: Female on ESCs, Male on motors

    • Anderson Power pole series connectors are promising and have significant use in FRC, but will require validation before we fully adopt them in place of the ol' banana connectors

      • Gender is not present on these but ideally three different colors are used.

  • PWM Signal Connections

    • Should be done with with standard twisted PWM cables. Ideally locking stuff so it doesn’t pull out easily.

    • Simplest solution is often the best so sticking with these seems ideal.

    • Gender convention: Male pins on the signal generator and female sockets on the signal receivers.

    • We will use mechanical locking on the headers, copying how it is done in Vex to lock the PWM connectors into the board they connect to.

      • Where this is not viable we will defer to hot glue

  • Other low voltage signal connections

    • Debug versions should be done on standard 100mil pitch headers and jumpers

    • Flight versions should copy Pixhawk connectors whenever possible

    • Specific components will follow manufacturer recommended connectors if we for sure want to support it

      • i.e. the VectorNav VN-300 has it’s own connector we should just use since we are going to use this component on our system for sure!

    • If all the above do not offer adequate specification for a low voltage signal connector we will defer to automotive and marine standards and document here

LED’s

For realism, we will have regular Nav lights on the dirty 5V or 12V rail, as well as a green PAX aboard light that is on a 12V or 5V relay controlled by ZP.

Custom Hardware Mounting Hole Specification

For general custom EE flight PCBAs going forward on ground station and aircraft we will follow this mechanical mounting hole specification:

M3 - Any PCBA with area exceeding 2500 mm^2

3.400mm hole diameter (0.1mm tolerance)

6.000mm annular ring diameter

M2 - Any PCBA with area exceeding 750mm^2 and less than 2500mm^2

2.400mm hole diameter (0.1mm tolerance)

4.200mm annular ring diameter

No Mounting Holes - Any PCBA with area less than 750mm^2

No mounting holes will be present on board of this size.

All Mounting Holes will follow:

Electrically not connected to the PCBA (frame is ideally floating potential)

Eight vias (plated drills) placed evenly in the annular ring (in whichever drill size is used on the board (so effectively left to EE in charge to decide on via size)) for mechanical stiffness.

Electrical components and electrically pads should be at least 1mm away from the annular ring to avoid damaging the PCBA when mechanically bolting the board.

Groundside Architecture

On the ground, there will be a primary “Ground Station” GS as well as the two tracking antennas “T_Telem” and “T_VRX”. GS Will be able to run unsupported (no power, no internet), for the competition for a minimum of 1 hour or from a standard wall outlet. Main batteries should be included within the GS Enclosure as the enlosure may be left outside overnight in inclement weather. All of GS should be weatherproofed, or be able to collapse into a weatherproofed box (it could be sitting in a mud/ or a puddle).

...

Groundside Components:

Telemetry & Control

Video

Optional Tracking Antennas

...

Airside Architecture

Now that we know what components are going on our drone, let’s talk about how they’re going to be laid out on the drone itself. This page will be finalized on Nov 6, 2022. After that date, any changes must go through a formal RFC process involving all subteam leads.

Airframe Design

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Mech to add information about the airframe design, with information about the wings, coating process, dimensions, structural tidbits, links to relevant pages for files / assembly instructions / operational limits & capabilities / etc.

Propulsion

lift, push, offsets, spacing?

Wings

wongs.

Servo locations? numbers? gg

Tail Section

Rudder/elevator

Fuselage

Fuselage is main passenger compartment?

Avionics Compartment

The avionics compartment will house all the airside compute. The compartment should be weather resistant, but be mounted on the drone in a way such that all electronics are easily accessible and serviceable with minimal effort (ideally no screws removed to plug/unplug connectors from any of the onboard computers.

The avionics compartment should allow for airflow and cooling over critical components. The Pixhawk should be mounted center with the COG, and peripherals should be mounted as explained below.

Sensors may be placed in the avionics compartment, but they should be mounted where they make sense. See below

Landing Gear

Design, limitations, etc.

Lighting

Airside Hardware Layout

System Level Electrical Placement & Routing Guidelines/Information:

  • The frame should not be electrically connected (aka should be at floating potential)

    • Complies with: UL1740

    • This can be checked with a DMM (when the system is not powered)

    • This means that if a PCB we are using has electrically connected mounting holes we need to take proper steps to achieve isolation

      • Sometimes PCB mounting holes are electrically connected to a GND plane for thermal reasons so we should also approach thermals with caution on sensitive electronics

  • Conformal Coating can be used within reason

    • The pro of conformal coating is waterproofing and makes it harder to accidentally should with a screw driver

    • The con of conformal coating is it prevents heat from leaving a PCBA

      • So anything that is conformal coated should receive a thin layer at most

    • Another con is that it can be annoying to remove in the case of reworking a PCBA

    • For example it would be fine to conformal coat a flight controller that runs cool

    • However, for example an RF transmitter we would want to approach with more caution

      • We could place a large heatsink on the primary chip(s) using thermal paste

      • Then we could consider conformal coating the other portions of the board

  • Cables, especially longer cables, should be within sheaths when reasonable

    • This offers protection against abrasion during natural flight vibrations

    • Exception to this rule is shorter cables that are placed further from anything that could be abrasive, specifically cables purely within the avionic compartment of our aircraft

  • Avoid loops in cable runs if possible

  • Varying conductor types should be separated when reasonable

    • Generally we consider four different types of cables: Digital, Analog, Power, & Coax/Rf

      • Digital: Characterized by signals with fast edges

        • Definition of a fast edge in this context and some examples to be added by an EE

        • Generally transcieving in 0 and 1 states asynchronously or synchronously

        • I.E. a GPS module’s cable connection to our flight controller is digital

        • An IMU is an example of a particular digital device that is sensitive to external noise.

      • Analog: Characterized by signals with slow edges

        • Definition of a slow edge in this context and some examples to be added by an EE

        • Generally transcieving data in varying voltage states

          • Though some protocols we consider analog will also transmit some digital data as well

        • I.E. a hobby fpv analog video camera has an analog data output

        • An analog video feed out of an analog camera is an example of a particular digital device that is sensitive to external noise.

      • Power: Characterized by constant voltage varying current designed for power transmission

        • Generally the voltage is constant though higher frequency noise may be present

        • These conductors can have significant current pulses

        • I.E. a connection from a battery to an ESC

      • Coax/Rf: Characterized by oscillating signals across the spectrum (~20kHz to ~300Ghz) intended for wireless transmissions and notably contained within a coaxial cable

        • A coaxial cable, specifically for our applications utilizing an SMA or RP-SMA connector, is generally used to guide sensitive RF signals between transceivers & antennas.

          • It is also worth noting antenna placement is critical, this is noted below in more detail

          • SMA & RP-SMA connector info should be found in the corresponding connectors arch doc section.

        • Because coaxial cables offer strong noise immunity the routing constraints of these cables are looser than others

          • Coax cables are very good at eliminating outside noise

        • For further information see: Coaxial cable

    • Each of these type of conductors should be physically grouped together, however, each type should be separated

      • I.E. All power stuff near each other, all digital near each other, but power separated from digital

      • This grouping and separation is physical distance, though of course there are other factors

      • Within PCBAs these groups may be mixed, this is fine, we will assume the PCB designer has taken the proper care to avoid issues as necessary

  • RF Transceiver Care

    • An RF transmitter should not be turned on (given input power) without a proper antenna connected as this can permanently damage the transmitter

      • Possible violations of this policy should be reported in Discord and transmitters should be labelled as damage (notably degraded performance) may not be immediately evident. We don’t want to blame each other, stuff happens, we just want to note it for the future! If you do not feel comfortable stating this publicly feel free to DM a lead you’re comfortable speaking to who can relay the message without naming names.

    • Transmitters generally get warm

      • They require a lot of power and therefore require some cooling

      • They are sometimes designed to be mounted outside an airframe for ambient cooling of wind passing the frame. As we may not be doing this we need to approach this with caution.

      • Notes regarding conformal coating are above.

    • The lower the frequency the longer the distance we can get for the same output power generally

    • The higher the frequency means more bandwidth generally

  • Antenna mounting

    • GPS sensors in particular are to our 900 MHz and 1.3 GHz transceivers and should be mounted away from antennas operating at these frequency ranges

      • GPS frequencies are fixed frequencies are1100MHz and 1500MHz

      • Our transceivers will hop around frequencies around their range looking for available channels so they are capable of hopping close to GPS frequencies and causing issues

      • For context it’s worth noting a 900MHz and 1.3GHz transceiver are capable of stepping on each others frequencies as well

      • For further reference see Guide: 1.2GHz -1.3GHz FPV Video System - Oscar Liang & GNSS Frequencies and Signals

    • Radio waves do not like to change medium

      • Specifically they do not like to pass through materials of varying dielectric constant

        • Passing waves through some varying materials may be fine, but be careful!

        • At the frequencies WARG operates at (6 GHz and below) foam will not have a considerable impact on signal integrity

        • Rain will have a measurable impact on signal integrity

      • This means mounting antennas outside of cases/airframes and providing LOS when reasonable

    • Antenna polarity should be deliberate

...

  • (Antenna Mounting Continued)

    • Ground antenna should be mounted with as much distance away from the ground as possible

      • This is to reduce ground reflection and has a considerable effect on reliability of an RF link

    • Antenna spacing should be minded

      • Any device with diversity (multiple antenna inputs) should have it’s antennas mounted with some spacing between them. Always follow manufacturer guidance here.

        • IE our VN-300 has specific manufacturer recommendations regarding recommended spacings and clearances

      • Different devices should have their antennas spaced out

        • See notes about frequencies and channels above.

  • Some notes about lightning

    • This entire section can be ignored for WARG purposes on nice days and the odds of a lightning strike are relatively low so don’t worry too much about these guidelines

    • As long as the current from a lightning strike is allowed to pass through your structure relatively unimpeded it will not harm the system

      • Notably isolating important electronics from the structure is important for this, see above.

      • To ensure this is possible having a somewhat conductive frame helps

        • This is not possible for composite frames and thus more complex techniques can be employed

    • Lightning likes to, if possible, enter and exit through sharp points

      • Ensuring that the sharpest points on a region of the system are all not electrical elements (notably antennas) will ensure lightning passes where we want it to!

      • A side safety note is that people are also relatively sharp points sticking out of the ground, however, unlike structures, you aren’t replaceable.

        • Be sure in lightning prone weather that people are not the path of lowest impedance for a lightning strike! This can be done easily by ensuring taller, pointier, grounded structures are nearby humans.

    • For ground equipment (towers and stations) grounding rods can be used

      • Notably this may not be possible for ecological reasons as well as if our ground station is on pavement

      • Grounding rods should connect into the earth (with a pointed end) electrically to the sharpest point at the peak of the structure

        • Ideally, as mentioned above, the entire structure is conductive which makes this easier to achieve.

Layout Introduction

The plane will be comprised of 5 main sections: the fuselage, cabin, avionics compartment, wings, and tail. The avionics + passenger compartment will be part of the main fuselage, while the wings & tail will house more electronics. All mandatory airside compute & airside peripherals must be mounted.

...

Compute

The Holybro PX_ system should be placed as close to the center of rotation of the drone as possible, offset in ONE axis only to allow for the installation of the VectorNav VN-300 module. There is an arrow on the top of the Pixhawk, which should point toward direction of forward flight. Keep in mind that wires need to be accessible from the “back” of the pixhawk (I/O & FMU Output banks), as well as from the side for USB debugging as well as retrieval of the SD Card.

There is no strict need to electrically isolate the system (the baseboard & cube are already protected), but it could be helpful to mount the system on vibration damped material (yellow sticky tack is good for this purpose).

Batteries & Power Distribution

Batteries and Power Distribution shall be mounted in front of the passenger compartment, under the same access lid as the pixhawk & various other PDB/Sensors. Batteries will be multiple 6S batteries harnessed together to provide a total output of 12S.

The battery box should be easily accessible from the top so that battery swaps may be easily accomplished during task #2, and should be weatherproof and house the PDB, Batteries, and necessary power connectors in a manner that makes upkeep & plugging/unplugging/probing connectors easily.

Transmitters

Both transmitters (RFD900x, 1.3ghz VTX), should be placed in areas with adequate cooling/airflow. Airflow can be introduced passively (i.e., drone is moving through the air), or actively (i.e. a fan). These devices are not weatherproof, and care should be taken to place their antennas away from any other RF sensitive devices. Devices such as cameras, unshielded signal wires, IMU’s, and GPS devices may experience large amounts of RF noise if placed too close to the antennas.

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Electrical to provide insight on where the antennas should be mounted to minimize RF interference with devices such as GPS sensors, and also to provide detailed information on coax cable extensions.

The RFD900x will use the stock dipole antennas (the long ones), which means that RF Noise generated by the RFD900 may be fairly close to the source. It is recommended to use coaxial cable extensions to mount the antennas at least 20cm away from each other. Recommendations to put one antenna along the edge of a wing, and to place the other antenna vertically along a vertical stabilizer or landing gear. Maintain one antenna perpendicular to horizon and one antenna parallel to horizon.

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Mech to provide clarity on the actual mounting location of the VTX antenna.

The VTX will use a coaxial cable extension to a side-exit singularity 1280 antenna mounted on the horizontal stabilizer. The antenna may be mounted inside or on top of the horizontal stabilizer. Maintain antenna deadzone perpendicular to horizon.

Cameras & Related Peripherals

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There will be three pilot cameras. All cameras should offer +/- 10 degrees of adjustment minimum, up to +/-30 degrees is desirable from their intended direction. The mounting locations are as follows:

  • forward facing at front of drone, level with horizon.

  • downward facing, perpendicular to horizon.

  • Downward facing, at a horizon angle of -30 to -45 degrees mounted high at the rear of the drone.

The forward facing camera will be the primary in-flight camera used during transition & fixed wing flight, while the downwards facing cameras may be used during takeoffs/landings as well as searching for landing pads.

There are currently no plans to motorize or otherwise be able to move the cameras in flight. This means they must maintain a pre-set fixed position in flight.

All three cameras will be wired into the Video Mux Switch, which will then pass a single analog video feed to the OSD, before being passed to the VTX. See Airside Electrical Layout for more details on wiring and interconnects. The OSD and Video Mux should be placed inside the avionics compartment, and although they do not require cases, it may be prudent to electrically isolate them from other conductive materials such as: carbon fiber, exposed wires, etc.

GPS Sensors

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Mech to add additional information on GPS mounting solutions.

The VN-300 receiver (red box) should be placed as close to the center of rotation of the plane as possible, with the axis aligned (x is forward, refer to ZPSW Documentation for more detail). This can be done above or below the passenger compartment, but should be in a weatherproofed section of the plane with low external RF interference.

Both VN-300 receptors & their grounding planes should be placed 1M apart, facing directly upwards, above other elements. These will be mounted inside the wings.

One NEO M9N GPS Module needs to be placed in an easily accessible location on the drone. The kit comes with a mounting stand which means that it could be placed on top of the drone, away from RF noise, but there is no strict requirement for this. The safety switch on the GPS module must be easily accessible. See Airside Electrical Layout for wiring limitations.

Peripheral Sensors

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Mech to add additional information on the remainder of the sensors locations.

Airspeed sensors should be placed in clean air, facing forwards.

Optical flow sensors & rangefinders or lidars should be mounted at the bottom of the drone, in a sensor cluster without obstructions (clear or otherwise) in the fov of the devices.

It is mandatory to have at least 1 hereflow and 1 tfminis lidar module, the rest of the sensors are optional.

Airside Electrical Layout

Please see 2023-03-07 - Clarity on Electrical Components on Comp Frame . EE Team member to update with more specifics Daniel Puratich

General Wiring Guidelines

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Subject to change depending on what Anni decides to throw at people

  • Servos connect to I/O Output and follow AETR, L->R

    • 1/2/3/4 Aileron (LO/LI/RI/RO)

    • 5/6 Elevator (LE / RE)

    • 7/8 Rudder (LR / RR)

  • Motors connect to FMU 1-5

    • Mot X : FMU X

  • FMU 6/7 for Aux Lighting

  • FMU 8 for Video Mux

  • Telem 1 → OSD

  • Telem 2 → RFD900x

    • will need external Power

  • CAN1 → Hereflow

  • GPS1 → M9N

  • VN300 → GPS2

Power Architecture

The drone will run a 12S power system. The specific sources and rails are listed below:

A detailed description of how each device is being powered and which connector type is outlined in the following document: Power Distribution Architecture.

Wiring

All of the wires for the sensors will be pre-run through the frame in dedicated channels, with connectors left exposed near the sensor compartments and the avionics compartment. This means that any time a sensor needs to be replaced, we do not need to re-wire the entire sensor. this also means that when we need to re-wire the flight computers, we can use the cables that are already connected to the interface connectors an simply plug in a few large connector banks to our dev interfaces. Running more cables through the channels should be supported, but all necessary cables should hopefully be routed during assembly (or when it is easiest).

All sensors shall be connected to the respective device owners listed in the hardware components section. There will also need to be a single UART connection between ZP ↔︎ Jetson, as well as multiple (at least 5) communication wires available between the PX5 and ZPHW.

Connector Standardization

  • Gender Decoding

    • Gender conventions regarding what goes where are defined below.

    • Gender is defined by the metal conductors in all cases. Plastic housing should be ignored when deciphering gender. The manufacturer’s dictated gender decision takes preference over this, however, it will be clearly iterated here if that is the case.

  • XT series connectors are convenient, common in the hobby world, fairly reliable, and relatively cheap and will therefore be employed for all WARG DC power connections whenever possible.

    • COTS PCBAs after require solder pad connections which we will accommodate, but breakout to our prioritized connectors whenever possible.

  • XT60 connectors will be prioritized for any sub 150 A pulsed DC connection

    • For ESCs and anything smaller this should be prioritized

    • XT60-F is on batteries and so the XT60-F should be used on any voltage source and XT60-M should be used on any load. This gender convention is also used in the COTS world and keeps things simple.

      • Manufacturer PN Gender: “-F” is female & “-M” is male

    • Custom hardware will use XT60PW series connectors and follow the above gender convention.

  • XT30s will be avoided when possible for simplicity

    • While XT30s are smaller and meet our current requirements for lots of low voltage loads in order to minimize the amount of connectors we need to stock and use XT30s will not be prioritized when an XT60 can be used.

    • COTS loads and sources with XT30s will be adapted to XT60 through harnessing

  • XT90 connectors will be used for any greater than 150 A pulsed DC connections

    • COTS higher current 6S and above batteries often ship with these XT90s and so we will accommodate such a design decision as they are rated for the higher current.

    • Anti-spark XT90s should be used whenever possible to limit sparks from in-rush condition though this may not always be possible.

    • XT90 battery input splitting into ESC and converter connections should be done on a properly specified PCB with XT connections done in harnessing.

  • AC Mains is not used on any WARG aircraft and therefore a connector will not be specified

    • No voltage sources exceeding 55 V during nominal continuous operation are to be present on aircraft due to a lack of necessity and safety concerns

  • ESC BLDC Motor Controller Phase connectors will be specified in the future and require more decisions in the future.

    • 3.5mm banana connections is a solid option from the hobby world, but they can be a pain. Other size banana connections may be used as well on smaller aircraft as we come up with more specific decisions.

      • Gender Convention: Female on ESCs, Male on motors

    • Anderson Power pole series connectors are promising and have significant use in FRC, but will require validation before we fully adopt them in place of the ol' banana connectors

      • Gender is not present on these but ideally three different colors are used.

  • PWM Signal Connections

    • Should be done with with standard twisted PWM cables. Ideally locking stuff so it doesn’t pull out easily.

    • Simplest solution is often the best so sticking with these seems ideal.

    • Gender convention: Male pins on the signal generator and female sockets on the signal receivers.

    • We will use mechanical locking on the headers, copying how it is done in Vex to lock the PWM connectors into the board they connect to.

      • Where this is not viable we will defer to hot glue

  • Other low voltage signal connections

    • Debug versions should be done on standard 100mil pitch headers and jumpers

    • Flight versions should copy Pixhawk connectors whenever possible

    • Specific components will follow manufacturer recommended connectors if we for sure want to support it

      • i.e. the VectorNav VN-300 has it’s own connector we should just use since we are going to use this component on our system for sure!

    • If all the above do not offer adequate specification for a low voltage signal connector we will defer to automotive and marine standards and document here

LED’s

For realism, we will have regular Nav lights on the dirty 5V or 12V rail, as well as a green PAX aboard light that is on a 12V or 5V relay controlled by ZP.

Custom Hardware Mounting Hole Specification

For general custom EE flight PCBAs going forward on ground station and aircraft we will follow this mechanical mounting hole specification:

M3 - Any PCBA with area exceeding 2500 mm^2

3.400mm hole diameter (0.1mm tolerance)

6.000mm annular ring diameter

M2 - Any PCBA with area exceeding 750mm^2 and less than 2500mm^2

2.400mm hole diameter (0.1mm tolerance)

4.200mm annular ring diameter

No Mounting Holes - Any PCBA with area less than 750mm^2

No mounting holes will be present on board of this size.

All Mounting Holes will follow:

Electrically not connected to the PCBA (frame is ideally floating potential)

Eight vias (plated drills) placed evenly in the annular ring (in whichever drill size is used on the board (so effectively left to EE in charge to decide on via size)) for mechanical stiffness.

Electrical components and electrically pads should be at least 1mm away from the annular ring to avoid damaging the PCBA when mechanically bolting the board.

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Groundside Architecture

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Anni to update this

Mandatory Hardware

Two RadioMaster TX16s Mk II Radios will be linked together using their trainer ports. One radio, serving as the “master”, will use a TBS Tracer system as a short relay to the RFD900x, connecting only a PPM or SBUS signal wire.

Any power that must be provided to the groundstation will use Turnigy 3s 4000mah nano-tech batteries. Any cooling fans will be noctua 40x10mm 5v 3 pin fans unless mech or ee requests otherwise.

Telemetry & Control

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Mech to add finalized designs for static towers

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Electrical to update with batteries & wiring diagram for the towers

Telemetry will be provided via RFD900x, with the stock antennas mounted >20cm apart. There will be a USB cable which allows direct connection to the groundstation computer. There may need to be additional power supplied to the RFD900x to allow full power operation, and if such is the case it is possible to use XBEES in transparent serial mode instead of a USB cable, allowing the antenna to be moved further away. The RFD900 may require active cooling, so mech to add design that allows a fan to be attached (zipties are effective solutions).

Control will be provided using a TBS Tracer module, TX in the controller and RX outputting PPM or SBUS wired into the respective pin on the RFD900. There will be no downlink over TBS Tracer (i.e., no telemetry from the TBS Tracer). Wires from the rfd900 harness will be soldered directly to the TBS Tracer, providing power, signal, and gnd connections. It is important that the tracer and it’s antennas & wires are placed in a safe position where it cannot easily short and/or become disconnected or damaged.

Video

There will be 2 major components to the video system, one is the video relay and the other is the video receive devices. The video relay handles the transition between low frequency (1.3GHz) analog video into 5.8 GHz analog video. This video relay system will exist on a unique video relay tower, which houses the 1.3ghz antenna (singularity 1280), the 1.3ghz VRX, as well as the 5.8 GHz VTX and the respective antenna. Note that the VRX outputs video in an RCA format, and this will need to be spliced to solder pads or 2.54mm pitch pins on the VTX. The singularity 1280 must also be mounted so that the null zone is vertical.

If the 5.8 VTX were to be the Rush Tank Race II, then the antenna would be a u.fl terminated rush cherry w/long stem. If the 5.8 VTX were to be an AKK TS832, then the antenna would be an SMA terminated rush cherry w/stem. EE to provide clarity on whether or not adapters are needed. Both VTX will take signal from the video receiver, and share common VBatt & GND where VBatt is a 3S voltage. This VTX will be paired with the VRX, and can either be mounted on a tripod or a tall PVC pipe. This VTX may also require some degree of active cooling, consider how a fan may be mounted.

User endpoint Video Devices

All remaining VRX devices operate at 5.8 GHz, this includes:

  • pilot FPV goggles

  • FPV monitor

  • 5.8 → USB receiver chain

Pilot FPV goggles are up to descrition of the pilot, and will be provided RHCP polarized stubs or stems depending on preference. These goggles will likely need 3s power. EE to determine how they receive power and what connecters sneed to be made. We will likely try and record the flight using the FPV goggles using the internal DVR function of the EMAX Transporter 2. Pilots may choose to use their own goggles, in which case the emax will use stock dipole antennas and function the same as a 5.8 GHz Monitor.

The FPV Monitor will likely use stock dipole antennas, but allow flight engineer to monitor FPV footage in real time along with the pilots. Currently, one monitor has a 2pin JST to XT60 adapter, EE to verify functionality and determine whether or not to make more. The FPV Monitor is capable of an RCA output, which means that it can be used with an RCA → USB adapter. EE To verify we have enough RCA cables in the right direction to operate in this mode. Theoretically, you could have one 5.8 Monitor away from the flightline for the rest of the team to view with. Up to you guys GG it just needs power.

There will also be a dedicated 5.8 GHz Video Receiver, currently we have an RC832 module, but any generic 5.8 GHz Receiver will work. This receiver can either output RCA, which will be adapted to a USB format to be used as a webcam on a PC, or it can output in a USB format directly. This video feed will be fed into the groundstation computer to allow for landing pad detection, or to allow recording of the flight.

Optional Hardware

Optional hardware typically requires the use of ZP with custom telemetry.

Tracking Antenna

The antennas will use directional antennas to improve connectivity with the drone, and must be placed as far apart and as high up as possible. They can be mounted on poles, and stakes may be driven into the ground with guy-lines to keep them upright (much like regular 5G antennas). Grounding wires can be driven into the ground as well. The towers should be as far apart as possible (one may have to be behind the tent and one in front of the tent - hence why it is important to get them to be able to go as high as possible), so that we have minimal interference. Even though we’re using different frequencies, they are still close to each other and notch filters may help significantly in signal quality, as will antenna separation. Antenna Towers should support fully tethered & fully untethered operation.

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Two controllers will be linked together, with one controller being the “master” using the trainer port. This means that if one pilot is unable to continue flying, the second pilot can takeover simply by hitting the switch. CC: Megan Spee confirm this is ok w/u at comp?

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Software Architecture

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This section is only applicable if the compute units are mounted. Otherwise, refer to arduplane documentation.

This section will discuss the computers involved, before then diving into communication architecture as well as messaging formats, different flight modes, and fail-safe contingencies.

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