Note: Issues with APM1 user's level feature not working are now resolved. If you installed 2.8 we highly recommend you upgrade to 2.8.1 as 430 extra bytes of RAM have been freed up which reduces the chance of memory corruption (although we haven't seen any cases of this on the APM2 at least) .
Note #2: this release has not gone out for Traditional Helicopters until they can be tested fully. Flip and Toy mode have also not been fully tested.
Improvements over 2.7.3:
- Improved ACRO mode (Leonard Hall)
- Improved stability patch to reduce "climb-on-yaw" problem (Leonard, Rob Lefebvre, Randy)
- Rate controller targets moved to body frames (yaw control now works properly when copter is inverted) (Leonard/Randy)
- Less bouncy Stabilize yaw control (Leonard)
- OpticalFlow sensor support for APM2.5 (Randy)
- DMP works again by adding "#define DMP_ENABLED ENABLED" to APM_Config.h You can also log DMP vs DCM to the dataflash by adding "#define SECONDARY_DMP_ENABLED ENABLED" (Randy)
- Watch dog added to shutdown motors if main loop feezes for 2 seconds (Randy)
- Thrust curve added to linearize pwm->thrust. Removes deadzone found above 90% throttle in most ESC/motors (Randy)
- More timing improvements (main loop is now tied to MPU6000s interrupt) (Randy)
- GPS NMEA bug fix (Alexey Kozin)
- Logging improvements (log I terms, dump all settings at head of dataflash log) (Jason)
- fixed skipping of last waypoint (Jason)
- resolved twitching when no GPS attached (Tridge)
- fixed loss of altitude if alt hold is engaged before first GPS lock (Randy/Jason)
- moved Roll-Pitch I terms from Stabilize controllers to Rate controllers
- TILT_COMPENSATION param tuned for TradHeli (Rob)
- HAL changes for platform portability (Pat Hickey)
- Removed INSTANT_PWM (Randy)
As per usual PIDs are optimised for the 3DR quad with 850 motors and 10" props. If you're using more powerful motors/props and are seeing bad flight behaviour in stabilize, start by turning down Rate Roll P in 25% steps.
Please note that on this release we've moved the Roll and Pitch I terms from the Stabilize controller to the Rate controller. There's some evidence that says this can lead to flips on take-off if you move the roll or pitch sticks around as you take-off so we recommend you leave these sticks in the middle until you're in the air.
Please feel free to report issues you find in the discussion below and/or add them to the issues list.
Thanks and enjoy!