Hi,
We are trying to get a motor tuned using our Mitochondrik ESC for use with a multi-rotor system.
The issue we are seeing is that we cannot get reliable stability at high frequency step changes. We are currently running this in voltage control mode, and are playing with the relevant parameters. The propeller is a 18.3" x 6.2. The motor is a 160KV 5008 sized motor.
As far as the specifications, this propeller is the maximum sized propeller that will go with this motor. Reducing propeller size, or reducing the motor KV both seem to fix this issue. However we have used this motor/propeller extensively in the past with generic ESCs with no issues at all.
These are the best set of settings we could make work - though the motor is still able to de-sync reasonably reliably when the input is changed sufficiently fast. Whilst the rate of change is suitably fast for flying, the stability is not sufficient - especially when external factors such as wind are at play. Reducing the voltage ramp further is likely to impact stability of the aircraft.
Kv / Vramp / curr_bw
160 / 35 / 0.167
For comparison, our tests were not able to make a lower KV motor, of the same dimensions, with the same propeller fail with far more aggressive settings:
Kv / Vramp / curr_bw
140 / 50 / 0.175
The behavior is identical between the mitocondrik, and a myxa, ruling out some hardware issue. On the front of it, it looks like the propeller is too large for this motor and cannot sufficiently increase or decrease speed of the motor. However, as mentioned, this has worked extensively in the past, and still works on generic ESCs. Is there anything we can try to gain stable operation in all scenarios? Or is there some fundamental reason this will not work on this system?
It is worth noting that our testing is essentially a sine wave between two setpoint values that increases in frequency, giving large and rapid variations of speeds. It is extremely aggressive, however it does highlight issues very quickly.
Best Regards,