Need Assistance for an autonomous Rover Build

Course Questions
1

I am in process of building an autonomous rover, I am using sensored BLDC motors from another rover. This has hall sensors (a total of 8wires coming out of the motor), but I have brushless ESCs which only accept 3 wires, So I have connected M(a), M(B), M© from the motor out of the 8 wires with the three wires of the ESC. I have ignored the other 5 wires[Hall(a), Hall(B), Hall©, GND and +5V]. I am trying to connect now test my motor with my ESC by plugging the ESC 5V signal and BEC cable into the Pixhawk and run a motor test on my Mission Planner interface.

But I am not able to spin the motor, is there anyway someone can help with the build? This is kinda urgent as I have a lot of other stuff to do post this.

Thanks!

2

I am not a rover builder, and at the risk of asking a dumb question, you said you are ignoring the +5v and GND wires. So how are you powering your motors? The FC isn’t used to power motors. It just processes the esc signal, right?

3

Hi, thanks for responding!

I connected only the 3 phase wires of the motor to a sensorless ESC, assuming (like a fool) the motor might be able to spin like a typical drone motor. But it didn’t…Sensored BLDC motors need Hall feedback to start, especially at low speeds.
Sensorless ESCs (like most drone ESCs) can’t spin these motors from a standstill, because they rely on back-EMF, which the motor can’t generate until it’s already spinning.
So no Hall input = no motion.

Regarding the +5V and GND wires , those are meant to power the Hall sensors, not the motor itself. The motor gets its actual power via the 3-phase wires from the ESC.
The Pixhawk isn’t expected to power motors anyway, it only sends control signals (PWM) to the ESC.

I am now switching to a motor driver for sensored BLDC with hall input, this can run my motor as it is, but, I am not sure how I could take PWM signal from my PIXHAWK to this motor driver to be able to control it the way I would like to.

I have ordered this motor driver - https://de.aliexpress.com/item/1005006006596035.html?gatewayAdapt=glo2deu

But I am not sure how I will be able to connect and operate it with my PIXHAWK…

If you have any ideas, please let me know🥲

4

You don’t want to use sensored escs? Possible to generate initial back-emf manually to get it going?
I would refer you to the Ardupilot forum, but see you already asked over there. Good luck!

5

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