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.
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I've never had the 12c thing, but one thing i do have to be careful of, if i plug in the xbee it causes a restart, which is really scary, the heli was doing flips and rolls. had to shut the throttle and run like mad. i dont know if its voltage or maybe something else.
Well, I finally managed to get home before it got dark and managed to get the TR500 airborne, despite the failing light and 2 degrees of frost!
I had loaded the current MP update last night and I updated the TR500 with the latest code delivered from the current version of MP
I was very pleasantly surprised by just how smoothly the first flight went - I got rock solid stability, with no overcorrection or other shakes, using the P values Malcom uses on his 600 (P=1) for pitch 'n roll, and using the values from his screen dump of t'other day for the Yaw
Had to fly with a handful of right rudder 'cos I'd used the Tx endpoints to limit the rudder travel so as not to hit the tail pitch slider limits - but once I'd used the manual setup button for the tail travel in APM I ended up with about 3mm less than full right travel on the tail pitch slider, so no wonder I had to hold the tail with so much right pedal
I'll sort this tonight,. Also, I felt it could do with a bit more positive tail authority so I will have to alter the rate values (I think thats the right parameter to change?): if it's too vicious I can always expo it out on the ruddder D/R switch - I'm in the habit of calibrating the radio and setting the travel in MP with the expo switched out and the Hold switched in so I get the full 0 to 100% range on the collective pitch servo throws
Just about the only issue that arose was that, before frostbite set in to my fingers, the heli dumped itself hard down from about 10 feet up - the motor stayed at the same revs, so I suspect a mighty glitch in the APM - most probably it was a brownout, as the cyclic and rudder stayed in the same position and she descended under power on what looked and felt like negative pitch
Thanks to the 80's vintage Morley "spacehoppers'" there was no harm done, and not much bounce as I run them slightly underinflated (I've always found them ideal as training gear - they dont snag in grass, they slide beuatiffully when practicing flare-outs that get left a tad late, and they absorb a lot of ham-fistedness on my part
What I reckon happened was the power demands of the APM and the servos dropped the power from my Align 1900mah 7.4v rx pack, which connects to the Spektrum TX (an Orange clone since Speccy's UK prices are somewhat taking the P). It connects through an Align B6 voltage regulator.
I read with interest your posts on the various power hacks and capacitor power cacheing, butam reluctant to go thisroute unless I really have to - so I'll try again with a decent quality 8 to 10A BEC and a 3S 11.1V 3000MaH 30C pack - I just cannot see how the 4 digital servos and the APM,mag,sonar and GPS couldpossibly draw more than 8A unless a servo were shorted rather than stalled
So I'll retune the PID's and see what can be done tonight with a decent BEC and 3S pack - am not too worried about the weight as I'll need ballast to bring the CG just forward of the main mast, when the Sea King fuselage goes on, so it might just as well serve a useful purpose, and the 3S pack's ideal for this
Since the stab mode seems fine, next up is to test the Alt Hold then Loiter - one fianl questionet on this topic - I've installed my mag well aft, clear of any steel (incl screws!) with cable (pins) forward and components down. So how come the compass reafing on MP when connected is 90 degress West of where it should show - my dec value is correctly set for the locality.Does the mag rely on the GPS to reference North - I cant think that it does but cant think of a reason for the skewed compass reading
Thanks to you all for making this very satisfying maiden flight possible - your research and development work has proved invaluable!
DA
Has anybody tested the final implementation of the improved head setup code? I haven't yet. Hopefully I get lots of time to spend on this this weekend as my wife took the kids visiting family for the weekend.
I'm almost done my APM1 case. I still haven't decided the final mounting location. I started thinking about mounting it on the flanks of the heli, sort of beside the tail boom support. Anybody have an opinion on that?
I don't want it underneath. It won't fit inside the frame behind and below the main shaft, or anywhere else inside the frame. Behind and below the tail is my first option. I could also put it above and behind the tail boom mount.
I had a look at the 2.2B6 code to be get some sense of what they've done to us heli guys, in regards to the new PID tuning.
From what I can tell, they've pretty much left it alone, and I think functional. For Stabilize pitch and roll, it appears we are left with the simple P+I controller which IIRC, is how it was before. So, only Stabilize P+I terms need to be worried about. They have not routed our Stabilize PI loop to the Rate loop. That's what I was afraid of.
However, I have determined that if you don't have an external gyro, the Stabilize Yaw P+I loop is in fact routed through the new PID rate controller. I don't know how that will work out but I think it should be OK from what I've heard about Igor's PIDT1 system. It does mean I will have to retune my yaw system. Have to proceed with caution since helis have WAY more yaw authority than a quad.
If you try Acro mode, I believe you will get the new PID system. Proceed with caution! Randy and I have found the previous incarnation of Acro mode don't work at all for us. No telling what happens now. I suspect the same problems that caused it not to work with P+I will make it even worse with PID!
I have an idea on how to change Acro mode so that it works for us, and will probably look at that in near future. In a nutshell, acro mode acts like a rate mode gyro on the pitch and roll axes. I believe the problem is that the system gets confused by the vibrations from the rotor blades. I intend to make the system work more like a heading hold gyro in the pitch and roll axes. Basically, it will work exactly like Stabilize, except instead of returning to level when you release the stick, it will hold the angle you left it at.
Here's the latest thing I've been working on. I wanted to make an aluminum case for the APM, both to protect it, give me a good way to mount it and the receiver, and also to create a faraday cage. I got the bottom half done. The machining isn't great as my mill really sucks, and I'm an amateur.
I might consider making something like this for sale if there was any demand. I priced out some CNC machining and it could maybe be done for $50/each or something on that order. It's not too heavy... the bottom half is about the same weight as the APM. I don't thing it's something a 450 would want to carry around, but not a big deal for a 600.
And my camera mount I was working on, it might end up that I need to do something different. The large platform, I'm just not sure it's going to work out. The batteries may need to be back on the frame for balance. I'll see.
Hi guys.
I dropped the new heli.pde on to a freshly downloaded copy of 2.1.8r
Put the libraries in the correct place.
make the frame HELI_FRAME
verify/compile... i then get the following errors, if i dont change the frame type then it compiles correctly.
heli:245: error: 'class APM_RC_APM1' has no member named 'enable_out'
heli:246: error: 'class APM_RC_APM1' has no member named 'enable_out'
heli:247: error: 'class APM_RC_APM1' has no member named 'enable_out'
heli:248: error: 'class APM_RC_APM1' has no member named 'enable_out'
Hey guys, good news. I kinda got us halfway there, but had a couple stupid newbie programmer errors (I overflowed an integer!) and didn't realize that we needed to scale another number. Randy and I had a Skype session, and we fixed it all up. It's about 90% of the way done. I tested it on my heli, and it works, for real, real world.
Randy is going to make another few minor changes, and then will probably be posting it maybe by tomorrow.
So don't worry, we got this swashplate thing nailed.
Randy, we might need to bring those swash_max=1900 and swash_min=1100 and make them visible as parameters in MP, because I can already see that with the fix, I'm pushing some of my servos too hard at the limits. I think it should be easy enough to make them parameters and just list them in the parameters list until Michael could make a fix to the setup page?
Hi everyone - a little advice needed on the Gyro function in the latest code:
Finally got around to flight testing this morning - am running the latest Mission Planner download (.29) and updated to the latest firmware.
On the bench, everything works as expected in terms of collective pitch, cyclic movement and stabilisation. GPS links nicely, magnetometer loaded with correct dec, showing expected heading etc.
I did notice that, with the APM gyro enabled, the movement of the tail servo from the rudder stick input is almost imperceptible - but its in the right direction. I selected the manual throw setting, and got the full range of travel in the correct direction. I then selected Save and the rudder input response reverted to almost imperceptible again.
On picking up the tail and moving it smartly through 90 degrees, which is the way I test my Futaba GY401 setups, the servo responds with the sort of movement range expected, but the direction seems wrong.
I then tried reversing the throw in the setup tab in MP, but all this does is reverse the sense of the stick input. No help there.
So I proceeded somewhat gingerly to the flight test - the heli, a TRex500, is fitted with a huge pair of Morley inflatable floats (which kinda shows my age!), so I figured no harm done if I go careful with the tests.
The heli spooled up nicely, and the control reactions in terms of cyclic were as expected. However, on reaching the head spped where she went light on her floats, it became clear that the inbuilt APM gyro wasn't coping - further gentle exploring indicated that the gyro was trying to respond in the opposite direction and thus exacerbate the torque-spin.
Manual input to counteract the torque was completely ineffective - I think that the output from a manual input was wholly inadequate.
I'm going to set up an external gyro so that I can at least carry on with the flight testing, in terms of stabilise, alt hold and loiter modes. But it seems to me that I can't progress to the Nav modes using WayPoints and RTL unless and until I can get the APM gyro to work
Does anyone have any advice or experience to offer on how I can rectify the problems I'm having with the APM gyro functions. I've checked the forums and my setup thoroughly, and swapped out the servo (a digital HX jobbie) to no effect - I don't suspect the rudder servo being at fault as it works full travel when manually setting the travel in setup
Cheers everyone!
@ Robert... thankyou for working on it. I'm at work at the moment but i'l try it as soon as i get home :)
Ok guys, can you please try and compile and upload this? I've taken a crack at fixing the problem with the swash min and max movements. You will see that *absolute* servo movements are controlled by swash_min and swash_max in heli.pde. Default is 1100 and 1900, but you could change this before compiling.
!!!DO NOT FLY THIS!!!
I want Randy to check it first. I don't even know if it works. I can't test it because my APM is in pieces at the moment. If you try it, please erase/reset the boards and go through setup fresh.
ArduCopter2.1.1r8 - Rob Mod.zip
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