Please explain motor output signal

[HeliHenkie]

Hi all,

The motors of my quad sound very 'restless'. I have no better word to describe the behaviour.
Looking at the log_mot_motor graphs two motor show some kind of clipping. Motor output drops below 1125, the minimum motor output value.

What does this mean? Are the motors shutting down periodically?
How do I tune this behaviour away.

See attached picture.

Best regards,

Jan Willem

[bn999]

The motor output seems to mostly stay within a 200us range, which is more or less normal. If you want to see this decrease, you would first look to the D term of the rate PID. But, I would not change it if it is flying well.

However, the entire band of output seems to be low such that you are clipping to the low side. The motors will not shut down, but they will go down to idle. This would indicate to me that you are over powered. The motor / prop combination that you have chosen has too much power for the size / weight of your craft.

[LPR]

Jan

When two motors have lower motor RPM it usually means that a motor or two tilted a little and causing yaw which is then cancelled by the flight controller. The only way the flight controller can cancel the yaw is to run two motors faster and two motors slower. It doesn't take much tilt to cause a problem especially if you have a light load for the size of the motor and props.

Larry

[Max]

Hi Jan, to check what Larry is talking about, graph your MOT_YAW _PITH and _ROLL values (separately). They should each have an average value around zero. If the values are more on one side than the other, this would indicate a physical imbalance (twisted motors, etc) and should be corrected.

-Max