OK, I have been trying for a while now to get the basics working but seems to be unable to get it right, I guess I am not the only one struggling with this so some sort of detailed instructions will be helpful.
First of all. I have the quad copter set up for x-frame, tested all functions work ok, and it is kind of flyable in stabilize, but it behaves far from stable, I have tried loiter with almost catastrophic outcome, but I guess the advanced modes have to wait until it flies ok in stabilize first.
So what are the problems :
When taking off into hover it tends to go forward and right, after I stabilize it into hover with stick input, it looks ok, but releasing the sticks make the copter advance forward and also quite fast to the right.
I guess this has to to do with leveling and Center of gravity, and possibly ensuring that the frame is not "out of true", but how do I go about checking these parameters? I have leveled the copter on the floor, which I guess is "level", I have tried to lift the copter by the dome and the COG seems ok, I have eye-spotted the frame and motors and they all seem to be quite ok. What else can you do, or are there some tricks to go about fixing this? Or is there something wrong with the electronics in my copter? Any ideas? BTW running 2.049 for the moment.
It's the propellers that have to be level. It doesn't matter if the APM, frame, or anything else is level, only the props - after all, it's the props that generate thrust.
There are two ways to set level in the field, which is potentially better than setting level in mission planner, especially if APM is physically plugged into the computer (when you remove the plug, you will inevitably move the APM, which will affects it's relationship with the props).
The first way is to hold disarm for 10 seconds (hold yaw all the way to the left). This will just 'reset' the level in APM to the current position of the copter. Obviously, this is only a good way to set level if the propellers are perfectly level.
The second way is to hold arm for 20 seconds (hold yaw all the way to the right). This will engage the in-flight leveling procedure, which should last 45 seconds (although on my copter, it only lasts 13). When in-flight leveling is engaged, the roll and pitch stick doesn't just fly the helicopter, but adjusts the level setting based on your stick. Thus, if your copter is drifting forward and to the right, when you pull back and to the left on the stick, the level setting should slowly adjust to account for that movement such that eventually you'll be able to let go of the stick and the copter won't drift. Once the copter is stable, land it, wait out the rest of the 45 seconds (leds blink in a special way when in-flight leveling is engaged), and then disarm the copter (yaw left for 2 seconds) to save the new 'level' to APM. That's it!
BTW - very important; don't try to use in-flight leveling except in an absolutely windless environment! Also, fly the copter at least 4 feet off the ground to minimize ground effects.
Hope that helps. Let us know if any of that isn't perfectly clear.
Hope that helps.
Still not sure what the difference is between 'auto level' and 'auto trim' (if any). From the code, it appears these are the same thing.
You may be right, however, about the 45 seconds. That's how long in-flight leveling is supposed to last according to the build wiki (http://code.google.com/p/arducopter/wiki/AC2_Flying), but I only get about 13 seconds out of my APM.
I'm tying the in-flight leveling procedure but i'm not sure if i shall hold the arm for 20 secs from when it's disarmed or armed ?? Shall i arm first and then start the 20 secs ?
this is an old thread... this is the way to do it right now: (Thanks again Marco!)
1) assign Autotrim to CH7 with the planner (and to a 2 position switch in your tx) (redo radio config to get it to register!
2) at the ground switch on/off the autotrim function and see if the led with autotrim enabled start to "rotate" (not the normal led blinking function)
3) takeoff with autotrim off in windless condition, still your quad in the air and switch on autotrim and try to mantain your quad in the same position with a little stick movements,remembering that you have to make the correction and then back to center stick (not the throttle, lol) to see how he is placed in air... when you quad is firm enough switch off the autotrim function, land and disarm the motors
Then you can try loiter, not before...