I have APM 2.5, PX4 and Pixhawk.
To me there is no question that Pixhawk is correct platform for all new applications.
The APM is a fine and proven performer, but it has reached the limits of its capabilities and new firmware has already moved beyond it's memory and speed capabilities.
What problems have existed in the Pixhawk hardware wise were fixed early on and there is currently no reason to presume that the Pixhawk is less reliable than the APM.
And such firmware problems as it currently has seem to be primarily associated with the new capabilities and are being worked out rapidly.
And the additional and growing list of capabilities make it the logical choice.
The only reason to pick an APM now would be if you can pick one up really cheap or because a clone comes in a cheap multicopter like the Quanum Nova from Hobbyking.
All of my future copters and planes will have a Pixhawk (until the Fire comes out anyway).
No reason to throw away existing APMs, just might noit want to get any more of them, my opinion anyway.
I am a ArduRover2 Developer and have both an APM2.6 and a Pixhawk on two separate Traxxas Slash 2WD brushless chassis and the Pixhawk is by far the better navigation controller due to the fact that the Pixhawk is capable of using EKF while the APM is not powerful enough to do so.
The Pixhawk equipped chassis follows the waypoints much better, especially in 90 deg turns where there is no post turn overshoot and recovery across the heading to the next waypoint. Also the Pixhawk has mitigated the slight turn overshoot that we have experienced with the APM.
I presently use my APM equipped rover to map out a new course and then use the Pixhawk to fine tune the waypoints, Cruise Speed, Speed_Turn_Gain (turn speed) and Speed_Turn_Distance (distance to start decelerating for a turn).
Overall, the Pixhawk is the navigation processor to use for precision rover navigation.
TCIII ArduRover2 Developer
Great information, thanks! Do you power the Pixhawk the same way with the Power Module and a seperate power supply for the output rail? The information in the wiki was a little confusing.
Hi Steven, it depends on what you are doing.
You are best off powering the Pixhawk with the supplied power module (which also has battery current and voltage feeds).
If all you are powering are ESCs in a multicopter, there is no need to provide separate power for the servo out rail (multicopter), but if you are using it to power servos (Plane or Camera Gimbal) then supply separate power for it.
What TC3 says below is also true, the EKF gives better control for multicopters as well.
That's a mighty big RC plane in your icon.
Yes it, however, no plans to put Pixhawk on it! I do have plans to put it on a fixed wing aircraft though. Currently I use APM 2.6 and use the Power module plus a separate battery attached to the output rail. I am assuming from what you said that the same setup would be recommended with the Pixhawk?
What is EKF?
OK with you, APM is good enough for the moment depending of what you wanna do.
PixHawk is more reliable (thanks to EKF that allows some sensor failure) and, anyways, it will be required from AC3.2 if you want full features enabled (and for next features coming with future releases of course).
APM has reached its limits but, for my personnal use, it's still very good. If you compile yourself your sketch, you can enable and disable the features you want in order to be under the limit size (242kB).
CPU has no head room neither and choosing an APM now would be frustrating when new features will come out as you will probably be unable to run them.
After owning both, I believe pixhawk is the better choice. The pixhawk hardware is far more robust and some arducopter 3.2 features are not included with the APM's limitations. It's my choice for future applications.
On my helicopter applications I don't use the power module because it's simpler to just power the pixhawk with the servo rail.
That is where I get a little confused. On the APM 2.6, of course, you have the input rail and the output rail. I understand on the Pixhawk there is an rc connection, therefore, there is just an output rail. How do you power your servos and the Pixhawk without using the power module?