Hi,
I´m new to the ardupilot system, but I read a lot over the last view days. And with my problem I did the setup 10-15 times, but I can´t find a solution.
I calibrated the radio. ok
Servo movement direction. ok
Servo tim. ok
Then on the heli-stup:
When I click on manual the setup switch into servo direct mode. I set the max and min travel of the swashplate to e.g. 11° positive and 11° negative. This is just about 20% the way in each direction of the throttle/pitch stick of my DX8 (I didnt made any changes on the travel endpoint in the transmitter, every channel is on 100% 100%) Then I move the stick to 0° and press ZERO. Then I press save.
After this the setup switch back into flight mode. So far so good.
But when I now move the stick to its max positive, the swashplate reaches only about 6-7° and this on a stick input of about 60% up. Above there is no movement anymore.
On the negative way everything is ok. The swashplate move all the way down to -11° over the whole way from the stick to its negative max.
So what I´m doing wrong?
I thank you for any help.
Oliver
Replies
Just a thought i had a problem with the HUD moving when i was connected through xbee..
No of course not. I did this auto trim just one time in flight. The heli is standing still on the table all the time, and the HUD rolls right to about 60° and stay there.
I did some more testing and what I figured out is, that I have the desired tail servo movement only in pos hold. Is there a difference in the heading holding in stabilized and pos hold. As I understand the wiki these two flight modes have the same heading hold behaviour, but they don´t
In my case, in stabilized only the torque is compensated, not the reading from the magnetometer. When I switch to Pos hold, the current heading from the magnetometer is set and the tail servo moves to hold this heading. When I turn the heli e.g. 50° the tail servo move to one maximum and stay there. When I switch back to stabilized in this "50° off position", tail servo move back to center.
Hi,
yes it is weird.
Here are my parameters. I have to raise the STAB_YAW P value to 3 to have control about the tail at all. The other values are standard.
TREX450.param
Hi,
First of all.
Thank you guys for developing such a great piece of technics. It is so much fun to work with it.
With v2.7.1 I did my first flight in stabilized and pos-hold and it worked pretty well. Exept the roll and pitch maximums, they were to high at 45. The heli was way to aggressive in this axis. I put down to 50% with dual rate in my DX8.
The only thing I don´t understand is the tail movement. During the flight I always have to make a right input to keep the tail towards me. I tested it like it is described in the pre-flight testing:
"Next rotate the helicopter slowly. You should find that in a certain direction the rudder stays in the middle. This is the APM trying to hold that heading."
This isn´t working in my case. The tail servo only work against fast movements. I have the external magnetometer mounted on the tail without any magnetic disturbances, and its well calibrated. It shows exactly the magnetic direction as my old compass do. The only way I was able to fight against the tail drift was, to trim the tail servo in the heli setup, so that the middle position allready have a slightly pitch to the right.
Do I have to do something else to activate heading-hold?
Thank you.
Hi,
in the meantime I loaded v2.7.1 on my AP and with this version everything is ok with the swashplate after the frist setup.
I did it again with v2.7.3 and the problem was still there. Back on v2.7.1 problem is gone.
Hi,
for normal swash movement I don´t need to reverse the throttle channel. I did it just to try everything what R_Lefebvre told me.
Yes thats what it locks like, a lmitation. And it has to be related with the max collective value. Because when I set the max swash movement to e.g. 18° and -18° in the setup (direct servo), I get about 9° at 30% throttle stick up, and -18° at 100% down.
Thank you for your help
Yeah, I still struggle with this every time. Sorry, I'm just not sure what the problem is.
How I usually end up doing this is to go into the Advanced Parameters List, and find H_COL_MAX. Change it manually, maybe add 50 to the value. Then Write the param to update it.f Now, very important, you have to stop telemetry, and reboot the APM, then check the movement and reconnect telemetry. If you need to change the value again, then again, change it manually, write it, and reboot.
It sucks, but that's what I usually end up doing.