Try to send different PWM signals to the ESCs

[Hans12323 (Moritz)]

Hey guys,

I’m trying to send my own PWM Signals to the ESCs to let the motors spin independently.

But I only get them spin all and not a single one.

Is it possible to let a single motor spin by sending the PWM-value?
I’m using a RPi 3B+ as companion and use pymavlink.

Thanks for ur time and help

Greetings

[Hans12323 (Moritz)]

?? No one?

[EliotBR (Eliot)]

Hi @Hans12323,

I’m a bit confused about what you’re trying to do here. If you have something which can output independent PWM signals then you should be able send them as desired to the ESCs, in which case you can control each motor independently.

@Hans12323

I’m using a RPi 3B+ as companion and use pymavlink.

What kind of control board are you using? Pymavlink sends MAVLink messages, not PWM signals, so are you using a Pixhawk autopilot board, or something else?

Also, are you using our Companion software on your RPi (our standard Companion software only runs on RPi 3B, so unless you’re using Companion Beta there may be issues with this approach), or do you just have a Raspberry Pi that you’ve downloaded pymavlink onto?

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If you’re using a standard setup of RPi3B + Pixhawk + normal Companion software, this comment is likely relevant:

@EliotBR

Control of individual thrusters with a single message isn’t possible with the current MAVLink specification, but there are some workarounds for it discussed here if you’re interested.

Is there a particular reason you want/need to control individual thrusters? Generally control is simpler when it’s abstracted to the motion directions you want to command (e.g. forwards, turn left, etc), so I’m curious what your use-case is.

I would note that if you’re wanting to make your own control algorithm instead of the ones that are already available in ArduSub, you’ll have much lower latency and more frequent sensor updates if you implement your algorithm(s) within ArduSub (e.g. as a custom/modified flight mode), rather than in Pymavlink. I understand Python is generally easier to get started with when testing things, but if your use-case requires high performance control then it makes the most sense to implement that in the flight controller board firmware