AC3.4 Tricopter Specific Parameters

ArduCopter Copter 3.4
1

Hi, most of the the settings are either self explanatory or latest beta MP has some sort of explanation to them, however there are a few ones, I am kind of guessing, but not even 50% sure. Please advise what these mean:
MOT_YAW_HEADRROOM default 200, what does it do on a tricopter if we have MOT_YAW_SV_MIN/MAX?

MOT_YAW_SV_ANGLE my guess was its and angle at which tail prop needs to be to balance Yaw, but than isn’t this is what MOT_YAW_SV_TRIM does?

Thanks!

2

@artemen,
I’ll update the wiki tricopter page certainly before the official release but until then:

  1. MOT_YAW_HEADROOM - you can just leave this at 200. This just ensure that at least 20% of the total control can be used by the yaw controller.
  2. MOT_YAW_SV_MIN, MAX allow you to set the min and max pwm values for the tail servo
  3. YAW_SV_ANGLE allows you to specify (in degrees) how far over the rear motor can lean. So for example, if the tail motor can lean over to 30degrees, that param should be set to 30. This lean angle is useful because it allows us to calculate how much vertical thrust is lost as the motor is tilted over (so we can compensate for it)
3

Thanks, to clarify, the _headroom param is the amount of yaw travel reserved to stabilize yaw by the autopilot? I’ve increased it to 500 and it appears that yaw manual handling is also better difference is noticeable…

4

One more thing, there is a very easy way to know exact thrust angle in real-time, this is already present in triflight - cleanflight fork for tricopters.
hall effect servos have servo position feedback pin available or even routed out like this one. reading is just analog voltage which can be read with one of the ADC pins available.

thrust angle is crucial for decoupling Roll from Yaw on tricopters.

5

So, i own a small quanum trifecta. should i measure how far the rotor can lean without hitting anything ( fpv gear ) and then set MOT_YAW_SV_Max / MOT_YAW_sv_angle accordingly?

Do you know if the 80% output throttle cap for tricopters is still in place on the latest beta?

Thanks

6

How do I set the thr_mid value ? Since the ctun.throut scale seems to have changed, should I multiply it the average thrust by 100?