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Very slow response time

Hello everyone,

my name is Batuhan and working on a fixed-wing VTOL project in a university team. We decided to use Zubax ESCs to improve our overall efficiency for our final configuration, which will be a 13kg MTOW Quadplane with 3,6 wingspan. However, during the hover phase, we had issues regarding the response time of the hover motors (MN5212 KV340) and could not get the fast response that we required.

In comparison, the T-motor FLAME 60A HV ESC was 3 times faster in a step response from 1200 to 2000 PWM. The slow response of Zubax caused higher oscillations for larger inputs during hover.

We probably were not able to tune the ESCs correctly, despite following the tips for multirotor applications in the forum, regarding control mode and angular velocities.

Has anyone ever used the Zubax ESCs in a multirotor application? I would appreciate the help, thanks a lot!

Best regards,
Batuhan

Hi Batuhan,

Can you please share the configuration parameters of your Myxas? Which control mode are you using?

Hi Pavel,

here you can find the parameters. Voltage-Mode was used considering the recommendations from the quick start guide.

config.yml (1.9 KB)

Hi Batuhan,

There are 2 main parameters that need to be adjusted in voltage control mode to improve the step response:

m.current_ctl_bw and m.voltage_ramp.

Set them to default values and increase m.current_ctl_bw until the static operation becomes unstable (rotor disturbances or whistling sound at low rpm).

Afterwards, increase the m.voltage_ramp until dynamic operation becomes unstable. Just run the motor up to 60-80 % setpoint and then send negative setpoint (-20% for example). If the motor is braking slowly making a sound like a dying animal or you are observing RUNAWAY DETECTED message in the log, the operation is unstable. Decrease the voltage ramp. Usually it’s value is not higher than 30 V/sec.

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