Myxa Tuning for low RPM high torque application

Support Telega electric propulsion
1

Hi @pavel-kirienko and everyone!
We’re using 6 Myxas on a hexacopter that is driven by a novel propulsion system.
This propulsion system forces our motors to work at a relatively low RPM (500->1500) and high torques (these are within the motors’ limits)

During flight testing, we have been experiencing situations where the vehicle becomes unstable.
This only happens when the motors operate at the lower end of the RPM scale and are followed by an gradual increase in ESCs error count.
My suspicion is that these are points where the ESCs control loop becomes unstable.
In the following graph you can see how every time the command is at a low point - the ESC error increases:

image
image1705×987 15.3 KB

We are working in Voltage mode.
Should this phenomena be fixable by tuning the Myxa parameters?
Is there a systemic procedure to tune these? Or any recommendations of where to start?
Considering the work regime - should I opt for RPM control?

These are the parameters we work with:
Myxa4 before replacement 6-4-22.yml (2.1 KB)

Driven motors are Tmotor MN501 KV300
Myxa version is 0.3

Thanks!
Gad

2

Hello Gad,

The ESC gradual error increase means that the hardware current limit is reached. I.e. the motor phase permanent currents esceded 60 Amps. In the voltage control mode the current loop is not used. That’s why it’s impossible to limit the phase currents in the software. But you can limit the max motor current in the software if you switch to the rpm control mode. You can find the tuning recommendations in this post.