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.
The manual says you should dial down the CH6 on your TX to 25%?
Just a thought Robert.
Maybe it's just me. I did a more scientific analysis, comparing to past data, and trying to get the scales to match up for a direct comparison. What do you guys think?
The top one is old baro data, in my basement.
The second one is new data, in my basement. Same scale, but it looks different. The total error is similar, but the period of the oscillation is longer? I almost wonder if this indicates my aluminum box is actually helping to shield it from EMF?
Third chart is flying data from today. You can see how nice it looks OTHER than for those spikes! Now, during this test, I stuffed some foam under my case to try and add extra damping, and I think it made it worse. It wasn't as bad before.
Maybe the flying baro data just looks worse than I remember before because I'm staying pretty low altitude, so the "random walk" looks worse.
I had a minor crash today. Pretty sure it's just pilot error. I slammed it into the deck and busted the landing gear off. Somewhat of a miracle it didn't flip over and destroy itself! So, damage report is a set of cheap and flimsy but fancy looking Hobby King landing gear, a home-made tail fin, and a $5 set of tail blades. I can live with that.
The only time i get weird readings is when i had my mag plugged in the wrong way.
I was looking at your logs to see if i could match the scale, to mine, but yours seem to wander loads. did you hold bottom right on your collective to initialise the sensors before flight. Try unplugging everything and then taking a few readings.
Sorry to hear about your crash, what happened?
Yes, I did try to do arm/disarm.
The second graph is with everything unplugged, even my receiver.
Can you just zoom in on your graph (you can drag a box) and get a section 1000 lines long, and from 0 to 600cm. That's the best way to compare.
I'm not exactly sure what happened. I've done it a few times testing the yaw control, where I try to give a sharp input, but it seems like the heli also darts up or down. I'm not sure if it's a "bug" or if it's just that I'm moving the collective at the same time as rudder (Mode 2).
Anyway, so I did that again, and this time it went up quite sharply, so I dropped the collective, and it was coming down way too fast, hit the deck and bounced up because I had already stuffed the collective up. I pulled back and it just came down way too fast and pancaked hard.
It seems like a really stupid newbie mistake, but I'm not sure that I over-corrected as much as it appears. The weird thing is in the logs, it doesn't show a yaw input at all, ONLY the collective. I don't really get it. Is it really just pilot error, or is something weird going on? No idea.
I do find that with 2.4.1, the collective seems way more touchy than I'd like. I'm not sure if something happened to the collective scaling.
hmm, what tends to happen is when you put a hard yaw command in you lean on the collective at the same time, do u fly with just thumbs on the sticks? I use the finger and thumb method i find it gives me far more control. I think i was flying with the same code as you, and mine was quite bouncy, but i didnt put in any pitch curves in the tx. The only other thing i can say, which you probably wont be happy about is flying at a reasonable altitude, this will give you half a chance if something like that happens again.
Yeah, I know. As painful as it is, in the absence of any evidence to the contrary, I have to assume it was pilot error.
And yeah, I know I'd be safer higher up. Just with all the instances of fly-aways, I wanted to keep it low so I can stick in the ground fast if I have to. At least until I'm more comfortable with the new code.
Dear Malcolm - great work - now I need to run to catch up with you - I too flew out 2 packs on Sunday afternoon. Stabilisation in all axes is nailed and very solid. Yaw control good, tail authority more than adequate for my style of flying.
On both flights I switched in to Alt_Hold at about 5 metres and got sudden jumps by 1 to 1.5 metres before I quickly switched out again.
I have the hover point set at mid stick (+5.5 degrees) across normal (ie hover) and flight modes 1 & 2 - when switching out of Alt_Hold the stick was still mid-point so no issues with sudden drops - it just went back into a stable hover.
I think I need to tune the PID's for Alt_Hold - can you advise me of your current settings so I can use these as a base point - mine seem to be way out so I'll use your settings as a datum, like I did before with much success.
Could you post your logs please david.
My P Throttle_Rate is 0.350 & P Altitude_Hold is 0.350
The I terms i didn't have to move although this was on a clam day so may need to increase the I term slightly and decrease the P value slightly.
0.400 made my heli oscillate pretty hard and 0.300 made it non responsive.
Hope this helps.
Thats one good reason for having the your hoverpoint at mid stick, but now i know where my hover point is on my TX i should be ok :)
@ Robert, i may get good Baro readings because my board is directly underneath the Rotor mast and all of the frame work of the heli. Well out of the pressure zone of the blades.
But its only a guess.
Actually the first and second trace are taken in my basement with nothing running, so dead calm air.
I'm already getting a new APM1.4 board, as I suspect mine is failing, but now I'm wondering if the Oilpan isn't bad too.
fair enough, that'll teach me to not read the whole post :)
i replaced an oilpan when the system wouldnt boot and it turned out to be the APM.
But i have a spare now ready for the gasser.
Hope you get it sorted soon, would be good for all of us to compare Flights, logs etc.
Sorry not to have responded guys - was away on a three major ops back to back. Got home this evening so will take tomorrow off, and if the weather's half as nice as today will get some flight time in: Will check the P Throttle_Rate and P Altitude_Hold to the values you report - will log and re-post if it's still a case of bunny hops.
Just had a look at Jean Louis flying his quad on the 2.4 discussion running 2.4.2b it looks rocks solid, a little bouncy up and down but it sounded very windy.
Really looking forward to trying this code.
As long as the bench tests come back the same as they are with the code that i'm using at the moment then i have no problem testing it.
@ Robert, just so you know, i have flown it up to around 40ft with no problem, I'm not telling you to fly that high, just saying i have tested it at altitude and everything was good. (sorry couldn't reply to your point earlier)