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.
Thank you Andrew,
Well throttle fs seams working in all modes but auto.
I don't have telemetry log.
Dataflash log i have, but i don't really see how it works, so i have packed all for you. :)
I did notice this in my last flight.
Today i will try autotakeoff.
I also have a question related to this.
Does it matters where do i position the waypoint i add autotakeoff to?
What would you recommend me to look after before?
I have never tried this before. I have always threw my plane to the air the conventional way. Manual.
Thank you Andrew, and community!
This is a great place to be.
Glad you like it!
We have worked hard with Miguel the last few days.
We will release 2.4 soon. ;)
Thank you Paul,
Your post helps me a lot!
I have only one question: When does it locks heading?
When i switch to auto, or after i threw it?
You have both FS_SHORT_ACTN and FS_LONG_ACTN set to 0 in the parameters you posted. That means you have disabled failsafe in auto. Have a close look at the parameter documentation. That should help you understand the behaviour.
Hmmm.... I tought that is for telemetry only. :)
Incredible, how much i don't know. Even that i fly this autopilot since 2 years now. :D
Thank you very much for helping me!
I will dig myself a bit deaper into wiki, i promis! :)
Quote: Gábor: Incredible, how much i don't know...
I thought it was just me :)
Something I've noticed that I don't recall happening before: when I connect a battery without having the Tx on (yes I know, Tx on first always but sometimes I just want to check or see something), the failsafe kicks in immediately (great > enters Circle Mode), but the motor starts and runs on the ground! Is this normal or new?
Gabor, any room for an additional screen?
Hey Graham, I've experienced this in the previous version..
I flew today. Prior to this flights I was very confident in my EasyStar.2 autonomous flight capabilities. Now .... it is TUNNING ALLL over again with the new TECS.I hope to have the time and perseverance to have the same results as the other navigation formula. What is strange is that I had problems (that I never had before) with aerial speed sensor(not calibrated or...???)
So from my POV:
big step forward with big effort!
This has happened to me as well on several prior versions. But it's inconsistent. I have "cured" it by removing power and re-powering the APM. Also, I have reset the APM and reinstalled the firmware. I have no idea what causes it but the lesson is to always treat a propeller with respect, which I do.
Funny, I have a EZ 1 and using the factory reset defaults for 2.74b with the airframe settings, mine fly fantastically. I will tweak it but it's not really necessary.