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 can't tell you how to fix your servo movement in APMP GUI, as I haven't successfully used it yet. However, if you want to use the CLI method, here's what I do:
First, you have to make sure you've done the radio setup with all your trims centered, endpoints at 100%, etc.
Then, I change the endpoints of my collective, rudder, and pitch and roll to move them all to the center. So I start with about -30/+30 on collective and rudder, and then -50/+50 on pitch and roll. Now I run the CLI setup for heli, I run the 'm' command which is where you set the limits of travel. First I move the pitch/roll stick to the limits. This sets the roll and pitch to about 50% of full throw within APM, which I find is about right. Next, do the rudder. Move it to the left, and then adjust the endpoint out until it moves as far as you want. Then move it right, and adjust the endpoint. The reason I do it this way is slowly moving the endpoint while holding the stick to the limit is more precise than trying to carefully move the stick without going to far. It also gives you an actual number to work with. The problem is, sometimes you move the servos too far anyway, and AC2 saves these. That's ok. Write down the endpoint values that you're happy with. Then do the exact same for the collective. If you went too far, write down the values you were happy with.
Now, type 'm' again. If you are happy and did not move too far, you're done this step. If you did move too far, you will find that the AC code saved those "too far" numbers. You have to fix that. So go back and type 'm' again. This time leave your endpoints at the GOOD numbers which you wrote down. Nowmove all your sticks around. AC2 will save all those good endpoint values. Now type 'm' again to exit, and 'x' to save values.
Now, go back into your radio, and expand all your values back out to 100%! This is VERY important.
Now when you reboot your APM into normal mode, you should find that, for example, if you move the roll stick 100%, the servos will only move 50% (or whatever setting you chose). The same should be true for pitch, and collective. Unfortunately rudder doesn't work so simply. It's hard to test the range. One way to do it is to swing the heli around fast, you should see it move, but it also depends on your PID's, etc.... You will just have to trust this one.
Thanks for the reply robert, i have done it this way too.
i did it my way, then i checked what the endpoints settings were. Cleared the ACM and did it your way . i then needed only a small adjustment.
But the amount of times i go through the setup. i would have thought that the software for TradHeli's would have lowered the Pulse range.
I suspect its for the quads, may be they need a higher pulse range.
have you got any videos of the T600? i have a few of my razor600 flying there.
Yes, to a certain extent we are the red-headed step child of the quads. We largely have to work within the code they have developed. I suppose Randy could make it more tailored to us, but that would be a lot more work. And I'm sure as soon as he did cut the default pulse range, somebody would post up and say they can't get enough range for their particular heli! :)
I think it's fine the way it is. All we really need to do is nail down the procedure and post it to the wiki.
I'd prefer if we try to get instructions into the wiki, instead of an offsite manual. You can do what you like but, I think the wiki is the better place.
I haven't flown a lot on the new code, but it seems good. I had about five flights with circa 2.0.54 or something. Alt_Hold was terrible, but that might have been due to my sensors. Acro was unusable. I didn't test Loiter much, and then I had the I2C bug which caused a bad crash.
I've flown about 3 times now on 2.1.1r8. There was a significant change on the way the PI loops are handled, so expect to change your PI's. Big improvement in theory. But my stabilize was good with both versions anyway, I do have a flybar so... The I2C bug is fixed, so that's good. Alt_hold is much better, but I still don't have it tuned yet. My baro sensor is working better now, but the sonar is still terrible. I don't have Loiter tuned yet.
Part of the problem with Loiter is I'm nervous to test it because if it gets badly out of shape and I have to jump in to save it, I'm not confident enough in my abilities to be able to do that. I can fly OK, but regaining manual control of an unknown situation... I'm uncomfortable.
I've been following along with the quad guys lately, since there really aren't any other heli guys. I like to think the code is almost finished. At least this stage of development. But it's confusing because a lot of guys are still having trouble, but I/we don't know if it's their setup, or the code.... Some guys fly it and have stellar performance. But for some guys it's not working at all.
As I said earlier, my stabilize is great. Other than that weird lean to the right that popped up on Sunday. Acro is still unusable. I suggest using 2.1.1r8. You need the I2C fix that happened around 2.1.1. 2.1.0 still has the bug and almost bit me again on Saturday.
I tried to upload the latest code using MP, but couldnt get into CLI mode or connect at all, so loaded an earlier version (2.0.55) to check my APM was working correctly. All works fine, so i'm guessing i need a patch, you were talking about an I2C fix?
As for Loiter, if you dont ever test it then your kinda not moving forward, The way i moved towards it, was to only let the ACM control the cyclic. Not the collective. this way i had control of the height/power. when you hit the switch there is a lot less of a jolt. i never got to a point that i thought i would ever lose the Heli, even when it was doing large circles. Just flicked it out and stabilise would always level the heli.
I know what the problem is, had it once before. The large chip in the center of the board (Oilpan) has a dry joint, or at least a high resistance on one of the legs. It takes a wiggle with a finger and the code boots. So its gonna cost me another Oilpan. I may well go for the new APM2, hopefully this will be a little stronger.
Wow, that's interesting. I do worry about the effects of vibration on these boards. And you've had it twice?
I'm really worried about my GPS and Mag. The T-tail that I made shakes like hell when it's spooling up.
I know I need to test Loiter to move forward. I'm just working towards it. First I gotta get Alt_Holt to work.
I should point out that the first one was a failure from new, and martin from BYOD, tested it and exchanged it straight away. The last time i used the heli, everything was fine and i only store my helicopters in the spare bedroom, so you can rule out corrosion. The APM is mounted on gyro pads (futaba) and the heli is well balanced, I use matched blades (SAB) for the main and tail rotors. Its probably just a bad joint. it'll be ok for testing code on the bench, but i'm not flying with it.
I'm surprised your tail boom shakes, Trex 600 are a good heli, i have flown a T500 and it was balanced perfectly. It might be worth checking your blades, paddles, Tracking etc.
I'm off to martin tomorrow, hopefully he will have an oil pan in stock.
I will be flying on sunday.
Welcome back Malcolm.
You definitely shouldn't need to go through that involved procedure to set-up the swash. and you shouldn't need to adjust your tx end points - the issue being that if you do this you may be unable to "arm the motors" which is important if you want to reset the baro values and also start the attitude logging.
After all the troubles people were having Michael Oborne and I created a special screen in the APMission Planner (the last tab called Heli). It's got a "manual" button that you should first push to start saving the travel and then push again once you're done. This button also resets all the internal swash calculations.
It would be great if you could try to use this screen and then tell me issues you see we can get them fixed (Robert did this about a week ago and the issue was the manual button had gone missing so we fixed that).
getting more info on the wiki would be great..including a page on how to use the APMissionPlanner set-up screen!
@ Randy - sorry i have been off for a while, i didnt seem to making a whole load of new head way and needed a break, besides the weather got bad, and there is no fun standing in the cold trying to solve a Loiter issue :)
Have you flown with the Mouse sensor?
Will be testing that tonight... So this reduces the amount of throw internally on the APM?
I'm sure between Robert and myself we can sort out the wiki. The only reason i was writing a few bits to my own site was more for me, so i could got back and check if something wasn't correct. I'm good at forgetting things :)
Also i saw your Loiter test video, is looking promising - The circular motion was constant, have you tuned the PID's since?
I know i constantly bang on about this, but fly your heli without the APM and tune it so it virtually flies hands off for a few seconds with no vibrations, this gives the APM at lot less work to do, i think that's one of the main reasons i have had a little more luck with loiter than most.
@ Robert i'll take a pic tonight of my new GPS setup on the tail. I think your right your just seeing a more pronounced oscillation because of the height of your mount.
I'm going to check the blade tracking again on the weekend while I also do my testing for the cause of the sonar noise. Could be that. Last night I ran it with the tail blades off and head off but main shaft in. There was just some light buzz or hum in the frame. Nothing to worry about. So it's probably something in the head or main blades I think.
Maybe it's nothing, and as you say, just the new tail configuration lighting off. Since it's a T-tail, it's got a lot of mass up on top of a flat plate of vertical aluminum. I might try cutting off one side, making it an inverted L-tail, and possibly with a diagonal brace back to the mounting bolts. Something like that. I have to minimize the shaking.
I'm not sure if he's tuned his PID, but there have been significant improvements in the Loiter code that the quad guys have been working on which should help us.
My heli already flies hand-off in stabilize mode. It's real solid. Just gets blown around by the wind, so that's all Loiter will need to control.