Hello everyone,
Increase Throttle = No Tail Hold
This should be a pretty basic setting to change but I can't locate it anywhere. I'm running the Pixhawk on my Trex and when I quickly increase the throttle, the tail gives out horribly and the heli does some 360's. The heading hold mode seems to give out when the throttle is increased. I am looking for the parameter that will increase the gyro gain value for the pixhawk internal gyro. So far I have played with the Rate Yaw PID values in the "Extended Tuning" tab, but haven't fixed the issue yet. Right now, my PID values for Rate Yaw are: P=0.2 and I=.02 and D=0
Any recommendations?
Thank you very much
Evan
Replies
So I've played with this COLYAW value tonight and I am having no luck with it locking my tail in place during throttle increases. I've moved it all the way up to 30 and -30 (which should be way overkill) and all values in between and all it seems to do is add tail wag when I get up that high, but doesn't help counter the throttle torque. Any other ideas? Thanks for all the input so far!
Maybe this might help:
"Collective Compensation is Collective-to-Rudder pre-comp, similar to what some flybarless controllers use. It feeds some extra rudder when you give it more collective. It's V-shaped with the lowest tail pitch being at zero degrees collective, assuming you have the Zero Pitch point set properly on the collective." - Rob Lefebvre
I was asking Rob about some of the setting in the heli setup screen just today and this was one of them. So, if your problem is due to giving sudden "pitch pumps", then try playing with this value. There is a similar setting with the Beastx, for example, that is used to compensates for just this type of thing.
Have not played with it myself...don't know what it is called in the advanced parameters list, however like I said, it is located on the heli setup page and is called Collective Compensation.
Ok, no problem. I guess thats my other problem, I'm running APM Planner v2.0.8 and I don't think I have the heli setup screen that everyone talks about from prior versions, unless you know otherwise.
I just varied the values for COLYAW, which is the closest thing I can find to Collective Compensation, with both positive and negative up to +- 10 and it did not seem to have any effect on the tail kickouts. Strange. I saw in another post that it should be good around 4 or 5 so I figured 10 would be overkill.
Interesting, is Collective Compensation called "H_COLYAW" in the parameters list? Have you played around with this yourself yet? the description says the value can be negative or positive depending on setup, I guess I will try both if this is the correct param!
Yes, that is the name of the parameter in the list. You should be able to test it on the bench to make sure it is at least working in the correct direction, but it's slightly tricky. The reason is because the compensation is turned off unless the motor is running. So if you want to bench test it, you have to disconnect the motor, arm, and then set Ch8 high to simulate the motor being on. After the run-up period, the compensation will go active, and you should see the rudder servo move when you change collective.
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