Replies to This Discussion

Permalink Reply by afernan on July 3, 2011 at 10:34pm

Yes. And also, the pirates code (NG) had the posibility of hold the position (without height), then you can play with height by hand. I gess it should be easy to implement that in AC2. Now with the problem with baro, the only posibility in AC2 is using the SONAR in loiter, but when it overpass some heigth and goes baro and it start climbing without limit. Is unusefull.

 

Yesterday I´ve tested AC2.0.31 and main problems are still there. Baro doesn´t work (it goes up allways) and Loiter is very unstable. I needed to reduce a lot the P value (0.5) to get some Loiter without diverging, but then is very soft.

 

I´m just finished a new copter with APM V1.4 (previous was v1). I have the suspicion thet these issues are due to the APM version.  I´ll report the results .

 

Regards

 

Angel   

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3D RoboticsPermalink Reply by Chris Anderson on July 4, 2011 at 12:03pm

Angel, please download 2.0.33. Altitude hold should now be fixed, and Loiter is improved (although we still need to do a bit more tuning to reduce the motion)

Permalink Reply by afernan on July 5, 2011 at 12:15am

I´m just updated to 2.0.33 and I confirm that Altitude hold now is fixed for both baro and sonar. Loiter is not good yet. I have a lot of motion arround, diverging.

 

Maybe this is stupid question from my side, but why don´t use the pirates NG aproach (this code part) for loiter (position hold)?. It works just fine with the same hardware. There should be an obvious answer, but I don´t know yet.

 

Regards

 

Angel

Permalink Reply by mc_don on July 5, 2011 at 9:16am

board V1.4?

what are the differences in hardware?
I do not see in stores that ver 1.4

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3D RoboticsPermalink Reply by Chris Anderson on July 5, 2011 at 9:34am

The 1.4 boards (AKA "Hotel" or rev H) have been out since last year. Almost all users have that one. It's available in two versions: the original APM1280 (ATmega1280 chip) and the newer APM2560 (Atmega2560 chip, which has twice as much memory).

We recommend all new users get the APM2560 board. We're running out of memory on the older 1280 chips, and to be able to continue adding features and innovating we'll need to sunset APM1280 support. The current plan to is to support both boards until about version 2.3 of the APM and AC2 code, and then make future versions of the code APM2560-only.

We'll ensure that that the final APM1280 code is solid and full-featured and we'll fix any bugs that show up later, so people with those boards can be assured that they can continue to use them as long as they want. But the main path of future development will require 2560s going forward.

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Permalink Reply by mc_don on July 5, 2011 at 9:45am

ok thank's chris :)

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Permalink Reply by afernan on July 5, 2011 at 11:47pm

See the file attached

Attachments:

• Diferences.jpg, 28 KB

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3D RoboticsPermalink Reply by Chris Anderson on July 5, 2011 at 7:41am

Angel : Glad to hear that altitude hold is now solid. We'll refine Loiter over the next few versions so it's solid for most airframes right out of the box. The PiratesNG code is just a derivative of out own original ArduCopterNG code so we do know how to do this ;-)

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Permalink Reply by mc_don on July 5, 2011 at 8:29am

glad to hear it,  chris :)

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Permalink Reply by u4eake on July 5, 2011 at 8:00am

Can the loiter radius be set to zero ? Or would that introduce nasty division by zero errors, (copter has crashed, do you want to send error report :-) )
I actually don't want my hexa to run around in circles, I just want it to hold position.

Glad to read that altitude hold has been fixed in 2.0.33. I'll upgrade probably today (though it's a pain cause I have some custom code to blink leds when battery gets low and I implemented a restriction so that RTL doesn't engage on low battery when in stabilise, simple or acro)

Been testing RTL yesterday and it works nicely, but I have some remarks. RTL is determined at first good GPS lock after booting the APM. This is sometimes inconvienient, eg if I connect the hexa in the stationary area, RTL is in there too, which sends the copter flying towards my fellow pilots in the stationary area. Not so nice :-) Would it be hard to set RTL home when arming motors ?
Further I found that my copter largely overshoots its home point (10-20m) then turns around, overshoots again etc. After a few rounds, I had to take over, cause it also kept climbing (due to alt hold error I presume, which should now be ok then).
I tried to up NavD a bit, but didn't see much improvement. It is Nav_D that is used for RTL, right ?

Thx for all help !
U4

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DeveloperPermalink Reply by jasonshort on July 5, 2011 at 9:17am

I like the set home at lock option. Good idea!

I have the home overshoot problem fixed in the next version. I look at the desired loiter spot and slow down as we reach it using rate control and distance.

Jason

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Permalink Reply by Pbreed on July 5, 2011 at 10:14am

Based on the work I've done with my helicopter, adding a velocity control loop to the hover in position code is importat, it will make a big difference in the quality of loiter.

This allows one to respond  quickly to wind gusts etc...

The Doppler velocity sensing of the GPS is really pretty good.

 

When flying from waypoint to waypoint I also did this with a velocity loop.

As one approached the waypoint one would solow down. This makes sens for a helicopter/quad, not so much for a fixed wing aircraft.

 

 

 

 

 

 

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