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:
- new APM_Control attitude controllers.
- new TECS speed/height controller from Paul Riseborough.
- two new flight modes, ACRO and CRUISE
- new camera trigger by distance system, for better aerial mapping
- dozens of small fixes and improvements from two months of development
- lots more documentation, including tuning guides for all the new parameters
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
After a suggestion from Thomas in the 2.73 release thread, we have added a 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:
- added new GND_ALT_OFFSET parameter for ground station barometric correction
- made it possible to set the failsafe battery voltage and battery level at runtime via parameters
- added MIXING_GAIN parameter for controlling the elevon and v-tail mixers
- fixed stick mixing range in AUTO modes (thanks Soren!)
- fixed mode logging in dataflash
- added support for the EagleTree I2C airspeed sensor on PX4
- added new RCMAP_* parameters for re-mapping control channels (good for DSM and SBUS receivers on PX4)
- made it possible to configure board orientation at runtime, to make setup easier without rebooting
- switched to new task scheduler for more accurate internal timing
- added a new RELAY_PIN parameter for setting up camera trigger via a digital pin
- added secondary rudder support, useful for when a separate servo is used for a nosewheel and the rudder, or for v-tail planes with nosewheels
- fixed RTL glide slope when starting above the target RTL altitude. Descent should now be smooth over long distances. Many thanks to Kitsen13 for raising this.
- fixed a bug with FBWB airspeed control. Many thanks to Gabor for reporting this
- Added FS_LONG_TIMEOUT and FS_SHORT_TIMEOUT parameters. Many thanks for the suggestion by Aleck
- fixed handling of deadzone parameters on RC channels. Many thanks to Soren for reporting this
- many small C++ fixes from NeuroCopter. This sort of detailed review of our code is much appreciated!
- fixed analog in handling with some unusual devices - thanks to Andi for noticing this!
- added support for apparent versus true airspeed calculations based on pressure altitude, for better flight control at higher altitudes
- avoid writing unchanged bytes to EEPROM, for faster updates and less wear on the chip
- cope better with large yaw changes in the AHRS code
- improved the reliability of USB connections on PX4
- added PX4 support for RELAY (thanks to Marco Bauer)
- fixed handling of high spin rates in AHRS (thanks Jurgen!)
- removed support for the old APM1 1280 based boards.
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.
Happy flying!
Replies
Or this .log is better to analyse.
2013-09-28 18-03-35.tlog
Sorry,
here they are.
2013-09-28 00-29-24.param
Hello all!
Just tried 2.74b and having some problems with tuning on apm2.5. FBW and cruise are more/less ok, but when on loiter/RTL it is entering in some strange turns rapidly loosing height, and after switch back to manual, it is ok now. I have changed some params, in order to try it again on the field, meanwhile, please, if somebody sees some beginners mistake suggest to change it.
It is EasyGlider Pro running at
Here are the params and .tlog. 3s 2200mah and 900kv motor.
Question is related to airspeed sensor mounting on a nose propeller. In the wiki is mentioned: "If you are using APM in an aircraft with the propeller in the nose, the pitot tube must be mounted out on one wing, at least a foot from the fuselage to be outside the prop flow."
The stock silicon tube is just one foot lenght, I would need at least 2 x 1 foot to connect both connectors.
Is any issue if I am using a longer silicon tube? Or, may I replace that silicon tube with other flexible tube from market?
I did see some pictures installing pitot tube (airspedd sensor) on tail (fin). Is this good position? Is still on prop flow, but at further distance.
My plane is 2m wingspan with nose prop. I am looking to know the best position, a picture is welcome.
I finally got to try out the new Cruise mode and I'm having some strange throttle surging when using it. In this video you can see that Auto mode works perfectly, but as soon as I switch to Cruise mode the throttle gets very erratic. My tlog is attached.
http://youtu.be/_I7-954BsW0
The failed autolanding attempt is another question, but I'll save that for another day.
Thank you for any help you can provide.
2013-09-23 10-53-32.tlog
Hi all,
A strange thing have happened yesterday.
Can someone explain what is going on here? :)
I have a bet that somehow AS sensor cased this, but how?
I think it was not calibrated well on boot, and my plane have stalled.
Am i right?
But why did it go around? :)
Thx,
Gábor
Still having some issues maintaining altitude in Loiter.
There's a saying: "bank-and-yank", and this describes the method to turn a model plane quite well.
Well, we're getting, in almost every case, "bank" but absolutely no "yank", rather the motor throttles up despite the plane flying at an adequate speed.
Every plane I test loses between 10 and 25m in altitude at a point just before start of the upwind leg, the motor is screaming at that point (in the RVJet's case) and the plane is clearly travelling quickly so speed is not the issue, although it seems that APM thinks it is because why would it be increasing the flying speed rather than just LIFTING the DARN nose up! After turning upwind there is an excessive altitude gain because the plane is travelling so fast with only the slowing down of motor and plane that causes it to settle.
I'm working through the tuning guides but it's a slow, time-consuming process with results that are not always clear due to atmospheric and other factors.
Before TECS there was a parameter to mix elevator with bank angle but now things are much more complicated.
Is there a single definitive parameter that would stop this frustrating behavior?
Changing PTCH2SRV_RLL doesn't seem to be doing much, or must it be changed by a large amount?
Edit: Note this large altitude loss does not appear at the entry to the turn but it's worst just before entering the upwind leg
APM2.5, ArduPlane 2.74, external power non 3DR.
When I connect to Terminal menu in Mission Planner for Arduplane, I get the windows below.
Is that safe to fly like this?
All looks OK in Flight Data/Flighy Plane/etc and plane responds correct to all controls/GPS/Baro, modes, etc. I did all calibration 2 times and install 2.74 firmware 2 times also. Same issue.
If I reset APM2.5 by reset button and connect again, then I see correct the ArduPlane prompter with menus (test/setup/logs, ect).
I remember I did have the same windows with garbage chars when I did crash my plane 2 weeks ago. Not sure it was related to this.
When I use ArduCopter (with another APM2.5) in same Mission Planner, I never did see this garbage in Terminal window.
I am planning to fly tomorrow, please I need your input, I don't want another crash if this garbage is not normal.
Thanks, Chris
I posted some questions about the APM behavior here:
http://diydrones.com/forum/topics/strange-happenings-on-waypoint-mi...
I'm hoping somebody can take a look and advise. I have an important mapping flight scheduled for tomorrow and I want to make sure I'm ready. So far, no one has replied on my post.
As a teaser, you get to see a video of what happens when the airspeed sensor is reset to zero during an Auto mission. The TECS did quite well, but was clearly working overtime to make sense of the input change.
Tridge? Paul? Anyone?
Hi!! i have a question about setting a waypoint in to a "landing point".
I have a nitro Nextar .46 and APM2.5 with internal compass+speed sensor. I've callibrated all the sensors, radio, etc. auto mission, rtl, circle, fbw a + b, all works great.
Last week i try auto landing, i started setting some waypoints at low altitude at the landing area ( works perfectly nice ). Then in the 3th try i put the las point "LAND".
The airplane comes great leavel, and drecreasing altitude, then it arrive at landing point at ~ 5 meters from the floor, then it make a 45 degree turn and then land, at this point i switch my radio selector between auto to manual but it was locked, i have no control until it lands ( perfect landing but not in the area i spected). The question is : When it arrives to landing point you can not switch between ato to manual or stab mode ???.
THKS
Sergio Oropeza from Queretaro, Mexico.
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