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.
Question: I was fine tuning the Advanced Parameters and noticed that YAW2SRV_IMAX was at -36. I had done a CLI Reset so that, I assume, is the standard "factory" setting. HOWEVER, the explanation says the DEFAULT setting of 1500 centi-degrees should work on most airframes. Can you explain the contradiction and what is the right default setting.
darn, that's a bug. First one in 2.74! It's not really serious, and the effect with default parameters causes no problem, but it will prevent you from properly tuning coordinated turns if you need more than a very small amount of integrator.
We'll probably do a 2.74b release soon that fixes this.
I've just released 2.74b which fixes a bug in the yaw integrator noticed by Steven G, plus fixes a bug with FBWB aileron control.
It should be updated in the MissionPlanner downloads in a few minutes.
Thanks for all the hard work...looks like some good changes and I'm excited to get out and fly it! Is there any word on getting HIL back up-and-running? Please correct me if I'm wrong but the last version with working HIL capability is 2.68, correct?
HIL should be working fine. It certainly works for me on Linux. I haven't tested it recently on Windows with MissionPlanner and XPlane - I'll test that soon.
does the TECS controller work if I don't have an airspeed controller installed, or should I switch back to the old one just for safety?
Something I have never known with both Plane and Copter when updating is, do I have to go through full setup? Do I just load a Hex file?
I usually always erase eeprom and reset, but somebody asked tis question the other day and the response was 'no'.Is it just small updates that don't require this as I thought that PIDs changed with updates like 2.74 and therefore required eeprom clearing?
I have tried to find the answer to this, but am unclear.
Hoping someone will let me know for sure, thanks.
These sound like some exciting changes, thanks! I can't wait to try them on my X8! ...well, not the Acro one, but the Acro one will probably work well on my 1600mm P51D once I get that one built :)
If a new firmware requires an EEPROM erase then I would announce that in the release notes. I always try to make new releases not to require an erase.
If you like flying in MANUAL then you may well find that ACRO works well for you as well, even on non-aerobatic planes.
Thanks Tridge, I have every intention of giving it a try for sure.. I'll let you know how it goes next weekend.
Hi Tridgell, congratulations to you for this new outstanding development...
I have one question: for those who has not installed airspeed sensor yet, Could we use the new cruise fly mode also?.
Thank a lot