Developer

ArduPlane 2.50 released

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!

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Replies to This Discussion


3D RoboticsPermalink Reply by Chris Anderson on August 13, 2012 at 3:53pm

Jake, there's been quite a lot of discussion here about PX4. Maybe you missed the announcement?

Permalink Reply by Jake Stew on August 13, 2012 at 4:10pm

I find it hard to follow the blog posts and difficult to have discussions there.

I figure if it's important someone will post in the forums.

I guess that's the problem with having things scattered among multiple formats.

Thanks for the link.


3D RoboticsPermalink Reply by Chris Anderson on August 12, 2012 at 7:45am

The power protection can be added with two components described in the manual here. (These were supplied in the bag with all APM 2.0s shipped for the past couple months). The switch to an external GPS can be done as described here. Otherwise, the boards are the same. 

Permalink Reply by Mike Mac on August 12, 2012 at 7:35am

Rudder Tuning

　

I am trying to tune Rudder Mix (KFF_RDDRMIX) so that there is zero sideslip during a loiter turn. What parameter do I need to look at the well me which way to adjust that parameter?

　

I see that all the Servo Yaw PID’s are 0. Why is that?

Can I use servo yaw P (YW2SRV_D) to have the APM to automatically make the sideslip 0 during a turn. I really need a procedure on the best way to tune the rudder. This should make the airplane fly with minimum drag when turning.

 

.

 

Permalink Reply by Mike Mac on August 14, 2012 at 3:33am

No Comment ???????

　

So I take it that everyone just flies the default values. It would be nice to have a tuning procedure for rudder control.

　

.

 

Permalink Reply by Paul Marsh on August 18, 2012 at 6:59am

Hi Andrew,

Here's a little more on the strange waypoint following behavior I'm seeing.  I set up a 4-waypoint pattern, with waypoint 5 being a DO-JUMP to keep the plane flying.  The pattern you see below was repeated with each pass of the pattern.  The plane (in sim) actually behaved differently on each of the four legs, but consistently in this regard as noted.  From  waypoint 1 to 2, the plane followed an S-curve.  The actual point it was flying to changed during the leg.  It started off to the right (east?) and migrated to the center of the waypoint.  The plane clearly followed the moving waypoint.  However, from waypoint 2 to 3 the plane behaved exactly as expected with zero-degree cross track correction.  The orange line pointed to the center of the waypoint and the plane flew stright to the waypoint.  From waypoint 3 to 4 the plane flew a curve.  The orange line started off to the right (east again?) and migrated to the center of the waypoint as the plane approached.  Finally, from point 4 to 1 the plane behaved as if I had cross track correction in.  It overflew the line a little, came back and then flew straight to the center of the waypoint.

If this is a navigation bug, could it be related to the magnetometer?

Finally, although the oval pattern is gone in loiter, the circle is off-center relative to the waypoint (see graphic).  Did you make any code changes recently to correct the oval?  I did reload the firmware and things seem to have changed a little.

Thanks,
Paul

Permalink Reply by Martin Bellomo on August 19, 2012 at 8:11am

Why the pink line is pointing backwards?

Permalink Reply by Paul Marsh on August 19, 2012 at 11:06am

Hi Martin,

The pink line simply represents the direction and radius of the turn being commanded to the plane.  It only appears backward here because the plane is being commanded to make a right turn, but it's on the right side of the circle it's flying.  As the plane approaches the left side, that pink arc will line up pretty much perfectly with the circle, but only for a moment.

Paul

Permalink Reply by Mike Mac on August 19, 2012 at 11:21am

Where’s the documentation of what all those lines mean. I one is the heading but I have never seen anything that gives a clue – or did I miss that somewhere?

.

Permalink Reply by Steven G on August 19, 2012 at 11:29am

see here, http://code.google.com/p/ardupilot-mega/wiki/MPGCS for most. Don't see pink one but the rest are there.

Steven

Permalink Reply by Martin Bellomo on August 19, 2012 at 4:37pm

I Have to see more carefully but in my case I allways saw the line pointing forward and indicating the direction and radio of the turn.

Permalink Reply by Mike Mac on August 19, 2012 at 7:18am

 

 

Reset Mission – when do we get it?

 

I see that the RST_MISSION parameter is in the documentation but not available in 2.50. I really need this option. When can we expect the next firmware update?

.

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