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program motorstop for VTOL

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Jan-Willem
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program motorstop for VTOL

Hi guys,

First of all apologies for jumping into this forum and directly asking questions ;)

I work in the field of drones. For me ESCs are sort of black boxes and I found it time to dive a bit deeper into ESCs. Searching for more programmable ESCs I found this amazing open source ESC.

Now my question. I am working on a VTOL drone, so a drone that takes off and lands like a multirotor and flies forward (efficient) like an airplane. As you can see in for example this video https://youtu.be/triEnFLKqrQ?t=40 the 4 propellors stop at a random position, creating asymmetric and more drag compared to when the propeller is in the flight direction.

How complicated is it to program a VESC to stop the motor in this position when the motor is stopped (PWM 1100 or something like that)?

 

Thank you very much in advance!

Jan-Willem

 

vadicus
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You can use what's known to be "handbrake", it's already there and accessible via UART/CAN: https://github.com/vedderb/bldc/blob/80fffdea7340f3b7d4faea63f24339c2212...

You can set the amount of current to be applied to hold the motors, which I would think would be way less needed on VTOL compared to a surface vehicle.

 

 

NextGen FOC High voltage 144v/34s, 30kw (https://vesc-project.com/node/1477)

Jan-Willem
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Thank you vadicus.

Yes, the current needed to keep the propeller stopped is very low. It already stops in flight, just in a random orientation. So if I add the required orientation (for example 90 degrees) it would work?

 

vadicus
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Do the motors have position sensors? I think you can switch it to servo mode and set the desired angle. You might also want to come up with some logic to detect the position of the least resistance and hold it at that angle.

 

 

NextGen FOC High voltage 144v/34s, 30kw (https://vesc-project.com/node/1477)

frank
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Maybe it is even possible with HFI. The rotor positioning issue pops up once in a while. Usually it is solved using an angle encoder on the motor side.  AS5047P magnetic encoder for example.