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.
Oh, you did test it in the Sim? Well that makes me feel a bit better about it.
I'll load it directly from MP and see if it works better from there. Actually that would be a problem.
Is there a way of putting a setting in for the compass in MP as i have "components_up_pins_back" .
No, it's not possible with the MP version. But feel free to add an enhancement request :-). We could actually save >20 bytes of ram if we reduced the complexity of the orientation matrices for the compass...and after that it wouldn't be hard to add the flexibility to select the orientation.
..or better yet just flip your compass over. I use to have mine like yours (or rather I had components up, pins forward)..but I just gave in and flipped it over to be the same as everyone else and save myself some trouble.
That should have read as COMPONENTS_UP_PINS_FORWARD.
Its just so much easier using a gyro pad on the flat side and having the pins forward.
I've added it as an enhancement. :)
Malcolm, I went ahead and soldered the Mag onto the board. I'm really not sure it matters. These mag chips are used in mobile phones with speakers all over without issue.
Anyway, I'll let you know how it goes.
Every-time i try, i get some really bad errors, then i move it away and from the heli and the Line on MP points the right way. That's why its mounted some way back on the aluminium boom on a plastic tail fin, the fin is bolted down with 316L cap heads. Just trying to eliminate all possibilities of getting a bad compass reading.
Well guys, I got 2.4 loaded in my heli, and so far it seems OK, but I have not flown.
I spend the better part of yesterday and today working on a cool little program to run some LED lights in a scale-like fashion, and also add the functionality to allow us to easily see the status of the GPS and "armed", as well as battery status if you have that hooked up. It wasn't working, so I spend some time trouble shooting the code, only to find out that it appears my board is messed up so the Port K isn't working. :( I did bootleg it a bit and got it semi-working by tying directly into the "C" LED feed. But that was unfortunate as it was a nice bit of code. It's available if somebody else wants to try it, but you do need to do a fair bit of wiring.
Then I took it outside and tried spooling it up. As I feared, my mount is too soft. No matter what I did, the my APM mount was shaking, causing it to make the servos respond, causing more shaking... impossible to lift off. :( I'll change the dampers out for the firmer set and try again.
I changed the dampers out to stiffer ones, and it seems better. The natural frequency of the APM is now outside the frequency of the swashplate servos, but still inside the range of my stupid fast tail servo, so I could actually get a feedback loop going on with the tail servo where the vibes from the servo were making the APM vibrate, which made the tail vibrate.... I was getting a little frustrated until I tried turning down the Yaw Rate P. Made a huge difference. I roughly halved it from my old setup, and it seems much better now. I wasn't expecting that. So I guess everything is going to have to be tuned from scratch again. :(
It also sorta makes sense, because even sitting still, the tail servo was making more chatter than it did before. When I turned the Yaw Rate P down, it quieted right up.
Still no flights yet.
Makes me wonder though, maybe the softer dampers would have worked with lower gain on the tail.
Has the tail control changed since 2.1.1r8 Robert, because i was getting some really strange control issues on the bench?
I'm not specifically aware of anything but it's possible.
Are you using an external gyro?
no i'm using the APM gyro.
I would hazard a guess and say something did change, since I have to adjust my tuning parameters? My understanding is that while heli.pde hasn't meaningfully changed, that the way that the PID controls work has changed. It's sort of behind the scenes.
That being said, I haven't noticed anything particularly wrong. I get a healthy amount of throw when I move it around.
What numbers are you working with?