I'm delighted to announce the release of ArduPlane 2.50 for your flying pleasure. This release has a lot of advances to some of the core ArduPlane code, and should be a big improvement for many people.
Perhaps the most important change in this release is the new DCM code that does acceleration correction based on the GPS. This improvement is based on work by Bill Premerlani which really advances the state of the art for attitude estimation on small microcontroller based autopilots. The improvement in attitude estimation is very noticable in flight, resulting in significantly more accurate control. Many thanks to Bill for his patience in working with Jon Challinger and myself to bring this improvement to ArduPlane.
Other significant improvements include:
- updates to the barometer driver to sample the pressure and temperature much more rapidly, leading to better altitude estimation
- updates to the AP_AnalogSource driver to be interrupt driven, allowing us to sample all analog sources much more rapidly. For ArduPlane this improves the airspeed sensor on the APM2 a lot.
- updates to the waypoint completion logic, to use a "finish line" algorithm. This prevents the problem of circling around a waypoint when we miss it by more than the waypoint radius. The waypoint is now considered complete when we pass a line that is perpendicular to the track, and passing through the target waypoint.
- improvements to the AP_Mount code, allowing for control of roll/pitch/yaw stabilisation via EEPROM variables that can be set over MAVLink. This allows you to setup the mount once, and it will resume operation as soon as you boot. These changes also fix a number of bugs in the AP_Mount code, so it AP_Mount hasn't worked for you, please try again. Many thanks to Greg Fletcher and Amilcar Lucus for the AP_Mount improvements.
- Lots of improvements to the ArduPlane parameter documentation. This documentation should be the first place you look when trying to understand ArduPlane configuration parameters. Many thanks to Andreas Antonopoulos for his great work on generating these wiki docs based on the source code markup.
- New LAND_PITCH_CD parameter to control the landing pitch when not under airspeed control. Thanks to Jeff Taylor for fixing this!
- New SCALING_SPEED parameter that allows you to set the base speed for scaling PIDs. Previously we assumed a standard speed of 15 m/s, which is too low for fast aircraft. By adjusting SCALING_SPEED you can have the same set of PIDs for both airspeed and non-airspeed flight control.
There is one change in this release which may require some re-tuning. We were using the wrong value for time delta when using the PID controller for navigation roll. This has been fixed by making the PID library calculate the delta time internally, but it means that existing HDG2RLL_I and HDG2RLL_D values will be incorrect. I have fixed the defaults, but if you have your own settings for these, you will need to drop HDG2RLL_I by a factor of 5, and raise HDG2RLL_D by a factor of 5 to get the same result as for the previous release.
Thanks to everyone who has contributed to this release!
For the next release the plan is to concentrate on improved stabilisation and navigation controllers, based on the great work being done by Jon Challinger.
Happy flying!
Replies
Hi Everyone,
Jon Challinger and myself just found a serious bug in the ArduPlane 2.50 release that affects the attitude solution if you don't have GPS lock. The bug was fixed in ArduPlane 2.60 as a side effect of the work we did on dead-reckoning.
The bug basically meant that if you had no GPS lock the attitude solution would quickly drift off if you were climbing or sinking. If your plane was descending then it would think it was pitched up more than it was.
Unless you are very confident of your GPS lock I'd strongly suggest everyone update to 2.60.
Cheers, Tridge
Yesterday I did 4 completely autonomous missions, from Auto Take off to Auto Land.
Everething works perfect. APM2 and 2.5 code.
I´m still having the loss of altitude right after finish the Auto Take Off. but I lined up the waypoint 2 with launch position and that makes the altitud loss less stressing.
Hallo,
I used params for skywalker from Arduplane WIKI page (skywalker.param). In stabilize mode plane oscilates quickly in pitch axis (checked visualy - elevator oscilated fast), not like CG would be too rear, much faster. Can somebody help me which param I have to adjust?
Roll axis is stabilized perfect.
Using Arduplane 2.5, APM1 1280, Skywalker 168cm.
Thanks in advance.
Hi Andrew,
Is there a document explaining the source code of ArduPlane 2.50 (or any version before that), will be very useful? I need this understanding for my project which I am doing for 2-axis camera mount stabilization using servos.
Thank you!
Strange crash with APM1 and Arduplane 2.5 happened to me too. Flown 3 points in auto mode. Last WP was LOITER_UNLIM. The flight was perfect in almost stright line (2 WPs was in one line). Whole way is 4 km long, thus I followed the plane by car. On last WP turn plane made did loitering (cca 5 minutes) but during this loitering it still descent slightly and suddenly it rolled in 70-80 degrees and dived down in spiral. Then hit the ground.
Whole the time AUTO mode was active and thought LOITER_UNLIM will stay the plane at this position till I take the control won MANUAL mode.
Plane is (Skaywalker 168cm), no other injuries on electronics. But now i'm really doubtfull about APM and Arduplane.
The battery was discharget to only 70% (70% energy was still there) and APM has its own BEC so the problem is only with software or the APM itself.
Loitering seems to have problems with all versions of software for Arduplane and Arducopter thought. Or the sensors are goining to be wild after circles in loitering, who knows.
I am trying to plan my electronics power supply. Will an APM 2.5 be ok at 6v? I know the manual says not to exceed 6v, just wondering if being right at 6v is OK. I have a video transmitter that requires 6v minimum and I don't want to make the power setup more complicated than it needs to be.
Again strange behaviour but this time ended up in a crash...
Just after take off I started to make a turn . In stabilization mode when the plane was going horizontal it suddenly started to roll and fall until it crash. The plane was a bit pitchy, tending to put the nose down everytime.This was the same that happened firstvtime I flew with 2.50 but i could fly with more or less problems.
i will fix the plane and try the new 2.6 firm on my bixler, this time with default values for pids and see what happens.
Best firm for me was2.4 but i compile it and upload it without problems but then i am not able to connect to the board throw apm, not with mavlink 0.9 nor 1.0...
Hi,
I’m trying to locate where into the new APM 2.5 code, the compass calibration routine is.
Can somebody provide some assistance?
Best regards
Evan
I just finished my Arduplane. It has an APM1 in a Bixler. Tonight I was trying to get it set up for a maiden flight tomorrow. But, I'm seeing some odd behavior.
With the plane sitting on the floor in my office. Which is ~ 60ft ASL altitude. However, in APM the altitude being reported by the arduplane is all over the place. It changes several times a second and will go from 40ish to 180 feet randomly. It is all over the place. I'm not comfortable flying the play with the altitude readings all of over the place.
Any suggestions?
The plane does not have any other altitude sensors other than the barometer on the oil pan board. (my quad has the ultrasonic sensor)
Thanks,
Kevin
Today I was flying, testing some things and tunning others.
One of these things was Auto Take Off. Everything works fine but when the take off procedure ends and the plane goes to next waypoint the plane loses altitude for a moment and then start to flight in AUTO normally. I post the tlog.
2012-08-21 17-52-09.tlog
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