The APM dev team is delighted to announce the release of APM:Plane 2.74, a major new release with a lot of new features. This release is recommended for anyone flying fixed wing aircraft with an APM2 or PX4.
There are a lot of changes in this release, but some of the highlights are:
Scroll down for a more complete list of changes, but before that I'd like to give you a bit more detail on the highlights above.
New Attitude Controllers
The new "APM_Control" attitude controllers have been in development for a long time. Originally developed by Jon Challinger last year, they were extended by Paul Riseborough and made compatible with the existing parameter names. The key advantage of these new controllers is their improved handling of noise, and much better ability to tune for your aircraft. There is a new tuning guide in the wiki which gives detailed instructions on how to make the most of the new capabilities.
One of the big effects you will see with the new attitude controllers is better handling of pitch compensation in turns. The new PTCH2SRV_RLL parameter makes tuning for flat turns much easier, which has been a major source of frustration in the past.
The new controllers also handle sensor noise much better, especially if you use any D term in your roll or pitch controllers.
New Speed/Height Controller
The new TECS speed/height controller is the second major controller change in this release, and will make a world of difference for aircraft with an airspeed sensor. After a lot of testing I decided to make TECS the default in this release, although you can switch back to the old controllers using the ALT_CTRL_ALG parameter if need be. If for some reason you find you do need these old controllers then please let me know, as I am planning on removing the old controllers in the next release.
The previous airspeed controller for speed/height suffered from a major problem that it gave absolute priority to airspeed. If the aircraft could not achieve the target airspeed you had set then it would dive to gain speed, even to the point of diving into the ground. This made it quite fragile, and you had to be very sure of your airspeed configuration.
The new controller operates over a range of airspeed values, set using the ARSPD_FBW_MIN and ARSPD_FBW_MAX parameters. That controller will try to meet both the airspeed and altitude demands of the mission, but if it can't reach the target speed it will happily fly a bit slower, as long as it doesn't get below ARSPD_FBW_MIN. You can control the relative priorities of speed versus height using the TECS_SPDWEIGHT parameter. See the full tuning guide for details.
New ACRO flight mode
This modes brings rate controlled stabilization to APM:Plane, and should help give you an "on rails" manual flight experience. It is a lot of fun to fly, but it is not for beginners!
We're planning on expanding the ACRO mode in future releases. Right now it is great for "locked in" flying, and also good for loops and handles inverted flight very nicely. It doesn't yet handle knife-edge or prop-hanging.
New CRUISE flight mode
After a suggestion from Hein, we now have a new CRUISE flight mode. This mode is ideal for longer distance flying without a pre-programmed mission. It is like FBWB, but also does ground track heading hold, with heading update via aileron or rudder.
I've been testing CRUISE at my local flying field, and it is the easiest mode to fly in APM. Just steer the plane around the sky, and when you stop steering it locks onto a ground track and holds it. It isn't a good mode for takeoff and landing, but once you are in the air it is great.
New camera trigger system
When using APM for aerial mapping where you want photos taken at regular distances, the previous system was to setup a grid mission with a "camera trigger" mission item at regular intervals within the mission. That worked, but led to overly large and complex missions. You can now just set a single parameter CAM_TRIGG_DIST to the number of meters of flight between photos, and the APM will take care of when to trigger the camera. This makes for much simpler missions, and also works in other flight modes, including FBWB and CRUISE.
Lots of smaller changes
As is usual with a new release after a couple of months of development there were a lot of smaller improvements based on feedback from users. Many thanks to everyone who gave feedback and contributed patches!
Here is a partial list of the changes:
This new release has a lot of new features that should improve the flying experience for all APM users. The APM dev teams wishes all APM users many enjoyable flights, and we hope you have as much fun flying this release as we had making it.
Not really. We have already done tons of optimisation, but have also added new functions so...
Lets go here to talk a bit more about. ;)
Tridgell hello, today I tested the 2.74 version everything went well. except for the change in altitude down in guided mode, any idea that does not obey?
when you change altitude to climb guided mode works well. but when I change to lower altitude, the plane does not drop.
guided flight at the end of the file.
tlog file attachment
thanks for your help
Yep. This has happened to me in random occasions when the Tx is off. Haven't figured out this one yet. Always steered clear of the props in the field or removed it when doing some tinkering indoors.
for flat turn isn't better to control vertical acceleration instead of adding pitch compensation in turns?
in turns more elevator is needed instead more pitch angle!
Thanks for the report and the tlog! It is indeed a bug, and I've pushed a fix to git master.
The bug only had the effect you saw if the target map position in GUIDED mode was very close to the current position. If you ask the plane to fly a significant distance and change to a lower altitude it will do it fine, although it will level off at a slightly high altitude.
The fix will be in 2.75.
Is it true, that even if i don't use auto trim, trims reset on boot?
yes, although it has a check for extreme trims. If the new trim would take roll or pitch trim to within 20% of the end of the range then it will not do the trim. This is to try to catch the case of people powering on with the transmitter off.
Partridge thanks for your quick response. on the same mission. I use the function CAM_TRIGG_DIST seems that sometimes shoot photos before the scheduled distance. would also be great to have a button to disable the function CAM_TRIGG_DIST. in an easy and fast. or it would also be a good idea that could set a waypoint to another waypoint, to avoid non useful photos.
these are the results of CAM_TRIGG_DIST.
I would also like to have a button to change the loiter radius. I use it a lot for testing video camera zoom.
only those suggestions.
thanks for your great work.
I use the function CAM_TRIGG_DIST seems that sometimes shoot photos before the scheduled distance
The flashlog should have CAMERA log messages with the latitude/longitude of each image. Can you show some examples where it gets the distance wrong?
Note that it uses the position of the aircraft, not the position the camera is looking at.
Sorry for the late reply.
I'm using a Multiplex Mentor: http://www.aufwind-magazin.de/redaktion/mentor/img/1.jpg
An electro trainer with 2 kg TOW. It is well powered.
I was just about to disable TKOFF_THR_MINSPD and use TKOFF_THR_DELAY instead. :D
I will try to set TKOFF_THR_MINSPD to 2 or even 1.
Watching my vids back that should be enough. Only if my last was the worst case. :D
When i have space nothing bad can happen. The worst is that the plane lands. Isn't it?
My ES2 is pitching down a bit when it aply throttle. it is not that bad, but feels unconfortable when flying low. :)
I have also noticed that my OSD has a kind of latency now. Did datatransfer got slower?