Manual Control Lost during flight with Flight Core V2 + VOXL2 Setup
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TLDR: Is a 5V/6A rail (ex: Power Module v3) able to power both the Flight Core V2 and VOXL2 without manual control dropouts? Or is there a specific setup required for this configuration to run reliably?
We are attempting to fly with the Flight Core V2 as the flight controller and VOXL2 as the companion computer. We are consistently experiencing manual control loss when connecting to and arming the craft. According to the logs, there are significant periods (hundreds of ms) where manual control drops out.
Our first setup was to power the Flight Core V2 via USB from the Microhard Modem Add-On's USB port. The Microhard Add-On is in turn mounted and powered by the VOXL2 which is in turn powered by the Power Module v3. Our theory was that the Flight Core V2 was struggling to be powered via USB, so we changed to a second setup: VOXL2 and Flight Core V2 powered by the same 5V/6A rail from a custom power board that has a very similar 5V rail to the Power Module v3. We still saw the manual control lost issue.
Notably, we are already suspicious of the Power Module v3 and its capabilities. We had a pre-flight check issue that claimed "Avionics power low" that was fixed by swapping out the Power Module v3 for another, suggesting that their power capability may be marginal for this use case or perhaps inconsistent for some other reason.
Alternatively, if there are other suggestions as to why we are losing manual control, please feel free to comment on that as well.
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you can see this post regarding "Avionics Power Low", in short you can ignore it https://forum.modalai.com/topic/2051/avionics-power?_=1716249395852
You should definitely not be powering Flight Core with USB. The APM is far more capable.
What R/C are you using? This sounds much more like an RF issue than a Flight Core issue. If the Flight Core logs are valid, then it's running fine.
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Hi @jacobcayetano1
Our Power Module is proven to deliver 30W continuous over the full industrial temperature range.
I'd be shocked if you can find a better module with all of it's features out there for this price point.
I encourage you to stress test it using a load box and you'll see how reliable it is. I'm happy to share a few of our validation plots if you wish. We also unit test every unit with a 3Amp load (15W) before shipping.
Let me know if you have any other concerns about the power module.To add to what our Moderator has posted, the QGC "Avionics Power Low" feature and warning is useless. The ADCs on STMicro parts are frankly terrible, plain and simple. That is why we use a 16-bit INA231 on the power module for current measurement and reporting.
Additionally, You cannot power the FCv2 over USB fully featured as noted here:
https://docs.modalai.com/flight-core-datasheets-v2-functional-description/#power-supply-and-power-source-mux-details
That USB power option is provided as a convenience for programming w/o a bulky battery. -
@Vinny @Moderator Thank you for the response.
The reason why we suspected a power issue is that the Flight Core PX4 logs have gaps in data. My apologies as I should have included that info initially. Here is an example from manual setpoint data.
Here is a scatterplot for throttle manual setpoint data to show that those straight lines on the line graph are indeed gaps in data and not inhumanly smooth setpoint changes.
These gaps are consistent across all the data in the log, which led us to hypothesize that power was lost during these instances. We are using a custom controller that employs SBUS joystick protocol through QGC. Let me know if this info sparks any other ideas or is reminiscent of another issue.
