APM:Plane 3.3.0 released
The ardupilot development team is proud to announce the release of version 3.3.0 of APM:Plane. This is a major release with a lot of changes. Please read the release notes carefully!
The last stable release was 3 months ago, and since that time we have applied over 1200 changes to the code. It has been a period of very rapid development for ArduPilot. Explaining all of the changes that have been made would take far too long, so I've chosen some key changes to explain in detail, and listed the most important secondary changes in a short form. Please ask for details if there is a change you see listed that you want some more information on.
This is the first release of APM:Plane where ARMING_CHECK and ARMING_REQUIRE both default to enabled. That means when you upgrade if you didn't previously have arming enabled you will need to learn about arming your plane.
Please see this page for more information on arming:
I know many users will be tempted to disable the arming checks, but please don't do that without careful thought. The arming checks are an important part of ensuring the aircraft is ready to fly, and a common cause of flight problems is to takeoff before ArduPilot is ready.
Re-do Accelerometer Calibration
Due to a change in the maximum accelerometer range on the Pixhawk all users must re-do their accelerometer calibration for this release. If you don't then your plane will fail to arm with a message saying that you have not calibrated the accelerometers.
Only 3D accel calibration
The old "1D" accelerometer calibration method has now been removed, so you must use the 3D accelerometer calibration method. The old method was removed because a significant number of users had poor flights due to scaling and offset errors on their accelerometers when they used the 1D method. My apologies for people with very large aircraft who find the 3D method difficult.
Note that you can do the accelerometer calibration with the autopilot outside the aircraft which can make things easier for large aircraft.
After an auto-landing the autopilot will now by default disarm after LAND_DISARMDELAY seconds (with a default of 20 seconds). This feature is to prevent the motor from spinning up unexpectedly on the ground
after a landing.
It is now possible to configure your autopilot for hardware in the loop simulation without loading a special firmware. Just set the parameter HIL_MODE to 1 and this will enable HIL for any autopilot. This is designed to make it easier for users to try HIL without having to find a HIL firmware.
SITL on Windows
The SITL software in the loop simulation system has been completely rewritten for this release. A major change is to make it possible to run SITL on native windows without needing a Linux virtual machine. There should be a release of MissionPlanner for Windows soon which will make it easy to launch a SITL instance.
The SITL changes also include new backends, including the CRRCSim flight simulator. This gives us a much wider range of aircraft we can use for SITL. See http://dev.ardupilot.com/wiki/simulation-2/ for more information.
Throttle control on takeoff
A number of users had problems with pitch control on auto-takeoff, and with the aircraft exceeding its target speed during takeoff. The auto-takeoff code has now been changed to use the normal TECS throttle control which should solve this problem.
Rudder only support
There is a new RUDDER_ONLY parameter for aircraft without ailerons, where roll is controlled by the rudder. Please see the documentation for more information on flying with a rudder only aircraft:
http://plane.ardupilot.com/wiki/ardupla ... udder_only
We have managed to keep support for the APM1 and APM2 in this release, but in order to fit it in the limited flash space we had to disable some more features when building for those boards. For this release the AP_Mount code for controlling camera mounts is disabled on APM1/APM2.
At some point soon it will become impractical to keep supporting the APM1/APM2 for planes. Please consider moving to a 32 bit autopilot soon if you are still using an APM1 or APM2.
New INS code
There have been a lot of changes to the gyro and accelerometer handling for this release. The accelerometer range on the Pixhawk has been changed to 16g from 8g to prevent clipping on high vibration aircraft, and the sampling rate on the lsm303d has been increased to 1600Hz.
An important bug has also been fixed which caused aliasing in the sampling process from the accelerometers. That bug could cause attitude errors in high vibration environments.
Numerous Landing Changes
Once again there have been a lot of improvements to the automatic landing support. Perhaps most important is the introduction of a smooth transition from landing approach to the flare, which reduces the tendency to pitch up too much on flare.
There is also a new parameter TECS_LAND_PMAX which controls the maximum pitch during landing. This defaults to 10 degrees, but for many aircraft a smaller value may be appropriate. Reduce it to 5 degrees if you find you still get too much pitch up during the flare.
Other secondary changes in this release include:
Many thanks to everyone who contributed to this release. We have a lot of new developers contributing which is really great to see! Also, apologies for those who have contributed a pull request but not yet had it incorporated (or had feedback on the change). We will be trying to get to as many PRs as we can soon.
Best wishes to all APM:Plane users from the dev team, and happy flying!