I have just bought the ArduPilot Mega 2560 Full Kit... plus the Triple Axis Magnetometer HMC5883L. I should have it built over the weekend.. then i'm off to a my mates machine shop, and i'll make the splitter plate for the lower frame onto which i am going to fit the Ardupilot. the magnetometer i'll put on the tail as suggested. I am going to use my X-cell Razor 600E. For those that dont know its around the 50 size nitro heli.
Do i need to buy any other sensors i.e. the Sonar... i can fly a helicopter all day long but this is my first time flying one with stabilisation so any tips would be gratefully appreciated.
If this works well then i am going to try and use it on my x-cell gasser. i can get up to 20 minute flights with this. But i think for the time being a battery 600 is the way to go.
i'll post some pictures when i have it all together.
I have APM1. Is there a way to do a disarm using mission planner? Or I am not sure how to do a arm/disarm to a heli.
Also I read something from here:
"Unfortunately I upgraded to 2.0.49 before going to Antarctica and didn't realize that flight log collection was disabled since I had the atmega 1280 version, so no logs"
Is there something changed about logging for the latest firmware?
My goal is trying to use RTL to recover from signal or orientation loss. Seems it is a long way to go still.
Hmm... I thought the arm/disarm works the same across all platforms? Just hold the collective stick to the lower right for like 5 seconds to arm. To the lower left for disarm. However, my pitch curve is not linear (for non-3D flying 46,48,50,75,100). I have to hit the throttle hold, and switch to my 2nd flight mode that has linear pitch curve, and then hold the collective stock to the lower right/left to arm/disarm.
Really? I'll have to check the code but I didn't think that disarming the motors restarts the logging. I think though that if you don't arm the motors, your logs will be mostly blank. In a couple of places in the code we check that the motors are armed before we write stuff to the log.
Re the autotrim..so did you leave autotrim engaged (i.e. channel 7 was >1800) for long periods while flying? That should only be used for very short periods of time (like 10~20 seconds) and only when you're in very stable flight. If you engage autotrim and then fly all over the place you'll get bad behaviour like you say (inaccurate roll and pitch readings) because when autotrim is engaged, it's effectively re-initialising the accelerometers .. do that while you're flying around leaned over and you'll get bad behaviour for sure!!
I didn't know how the autotrim works so I tried both have it on for a long time and also very short like less than 10 seconds. Both worked in a sense, but then, the progressively random drifting still come back and made the heli seemed off-trim again.
Really? I didn't know arm/disarm had any bearing on logs at all?! Is that new-ish?
Wesley, just to be sure, when you say you put your heli back in the same spot, and the HUD shows it's leaning... you have motor off right? You're not testing with it running? If it is running, then it could be classic "leans". If it's not running, and the HUD is changing in-flight, then something different is happening.
Another thing, when you "arm", how long are you holding the sticks? It only takes a couple seconds right? If you hold the sticks in the bottom right for... 20 seconds? It actually enters an automatic Leveling mode, which lasts for about 45 seconds. So if you did that, then take off and start flying, the 45 second period will end at some "random" time in your flight and capture whatever angle you were at. That could explain what you're seeing.
Just another idea.
The in-flight levelling feature (either Ch7 or the 20 second arming auto function) should be used very deliberately, and only in dead calm winds.
When I was done it, my 600 hovered totally hands off and went absolutely no-where.
I only "arm" in for a few seconds. I know about the 20 seconds thing to start the auto trim and didn't do that for sure.
I put the heli back in the same spot with the motor off AFTER i flew the heli for a few minutes. It's like this: Put the heli at a spot, re-level, fly off for a few minutes, come back and land, put the heli to the exact same spot, check level. And the level is changed.
As Wesley says, there is an arming/disarming..you can fly without doing it but it's better if you do because of the logging and also because it reinitialises the sensors especially the barometer. So it's not critical but it's a good thing to do.
As for the tail issue...I've seen that in the past. The time that I caught it in someone's logs it was caused by an intermittantly failing compass. The compass was mostly not working but sometimes it would send in a heading and this would cause a rapid change in which way the APM thought it was facing and would lead to this rapid turn you're talking about.
If you had working logs I would ask you to check the Mag Heading field in the ATT message but I guess that's not going to work! you could try running the compass example sketch (open Arduino, example, AP_Compass, AP_Compass_test) and see if it's able to report good headings or not. That will pretty much tell you if you have a hardware problem or not.
the leaning could be caused by vibration in your frame.
"The compass was mostly not working but sometimes it would send in a heading and this would cause a rapid change in which way the APM thought it was facing and would lead to this rapid turn you're talking about."
That happened exactly like that to mine last week. Apparently some of the 12 pins that connected my APM2 with the daughterboard didn't have good connections. According to the logs, I didn't have compass ready except a blip here and there, and caused the heli to do rapid yaws at times.
or you can use the mission planner GCS which automatically logs all flights and save in the Mission planner program log sub folder.
Good news on your success.
The controllers are separate and the best way to tune them (you probably already know) is through the mission planner's "ArduCopter PIDs" screen. I'd suspect that the parameters should be fairly close for waypoints vs loiter. It's likely the P value can be higher for the WP controller.
Wow, loiter, that's great. What are your settings/parameters?
FINALLY got my APM2 on my T-Rex 600E, and flew a pack! I have a couple of questions for anyone who can offer advice.
First, if I leave all settings default, there is WAY too much cyclic action. Full stick will bind servos pretty quick. I've reduced the maximum pitch and roll in the Heli Setup from 4500 to 3000. Will this affect stabilization performance? How else should cyclic input be adjusted?
On that same idea, I reduced the stabilization P term which reduced cyclic travel a bit, but obviously that does make things less responsive when flying.
I'm sure I'll have more questions, but for now I'm just glad to have that beast in the air again :)