I tried today dev 1248, with the variable alt hold feature. (with //#define ALTHOLD_FAST_THROTTLE_CHANGE commented out)
It works great on my tricopter
But there are some strange side-effects I noticed.
When in alt holt, one can put the throttle stick to complete minimum and get a nice slow decent. However, having the throttle stick at minimum appearently also disables some part of heading hold / yaw control (not sure what exactly). When throttle is above minumum, the tri is holding the heading ok.... however, when throttle stick at minimum, it suddely starts to slowly yaw by itself.
This might be specific to a tricopter. It is probably an old feature to prevent the tail servo from slowy turning, while idle on the ground.
I'm not a programmer, but I think this hidden feature to disable yaw control should be made inactive if:
- alt hold is active
- motors are armed
- //#define ALTHOLD_FAST_THROTTLE_CHANGE is commented out
- motor RPM above MINTHROTTLE
Perhaps just replacing throttle stick at minumum with RPM at MINTHROTTLE to disable yaw should be sufficient already...
It's no big issue, but just something I noticed today.... it probably showed up more pronounced because my tri tail servo is not yet straight (it crashed yesterday, and I had to mount a new servo arm, which affected the mid position... still have to properly allign and/or set TRI_YAW_MIDDLE).
Another thing (pilot related).
While in alt holt, and min throttle, to make a slow decent, I made the silly mistake to counter the slow rotation, by giving full yaw left for a moment.....
.... which is disarm
It fell from approx 10 meters up..... luckly it 'landed' absolutely level in the long grass, so no damage done whatsoever.
Perhaps we could add some feature to prevent disarm when in alt-hold, and MOTOR RPM (not throttle stick) is above MINTHROTTLE....
just to prevent silly pilot mistakes....
And maybe another idea to prevent pilot error....
When at alt hold, and min throttle (slow decent). If I would disable the alt-hold switch (which is my 'panic' reaction if I get into trouble), it would suddenly drop out of the sky (hasn't happened yet to me, but it's just a matter of time)....
Perhaps we could keep the copter in alt-hold (even though the switch is off), until the throttle-stick is well above minthrottle.
just an idea..... what do you think ?
Thanks again for this great addition....!