GregCovey
September 16, 2019, 12:23pm
596
Chad_Frazer:
I switched the tilt yaw parameter from 30 degrees to 13 degrees. On startup the motors go to a 90+13 degree angle, is this correct?
Or should it just be 90 degrees and I should mechanically adjust the servos?
I don’t know why this is so confusing for me!
I agree with Romeo_E on how he set up his Nimbus VTOL. The 13 degrees came from the FoxTech setup and seems to work fine for most of us because it provides a 26 degree swing on each tilt-rotor.
Here is a diagram posted by Rolf and some description by Tridge that may help your orientation.
It initially tries to centre both rotors (ie. both pointing straight up). To do that, it needs to work out what PWM it needs to put in to achieve the centering. If you look at the nice diagram from Rolf, you’ll see that as Q_TILT_YAW_ANGLE increases that the PWM needed to make the servo vertical moves more towards SERNOn_MIN.
The way the maths works is this:
for an example, lets assume Q_TILT_YAW_ANGLE is 15
it knows that at SERVOn_MAX that the servo is at -15 degrees (15 degrees angled back).
it knows the total angle the servo goes through it 90+15 which is 105 degrees
so to get it straight up, it needs to move the servo to SERVOn_MAX-(15/105)*(SERVOn_MAX-SERVOn_MIN)
As you can see, if you increase Q_TILT_YAW_ANGLE without actually changing the servo movement then it will cause the rotors to tilt fwd more.
In other words, Q_TILT_YAW_ANGLE is something you measure about the frame, not a desired angle. If you want to change the desired angle you need to move the servo endpoints.
