a) support for direct drive tails (uses TAIL_TYPE and TAIL_SPEED parameters)
b) smooth main rotor ramp-up for those without external govenor (RSC_RAMP_TIME)
c) internal estimate of rotor speed configurable with RSC_RUNUP_TIME parameter to ensure rotor at top speed before starting missions
d) LAND_COL_MIN collective position used when landed (reduces chance copter will push too hard into the ground when landing or before starting missions)
e) reduced collective while in stabilize mode (STAB_COL_MIN, STAB_COL_MAX) for more precise throttle control
f) external gyro parameter range changed from 1000~2000 to 0~1000 (more consistent with other parameters)
g) dynamic flight detector switches on/off leaky-i term depending on copter speed
2) SingleCopter airframe support (contribution from Bill King)
3) Drift mode replaces TOY
4) MPU6k SPI bus speed decreased to 500khz after 4 errors
5) Safety improvements:
a) crash detector cuts motors if copter upside down for more than 2 seconds
b) INS (accel and gyro) health check in pre-arm checks
c) ARMING_CHECK allows turning on/off individual checks for baro, GPS, compass, parameters, board voltage, radio
d) detect Ublox GPS running at less than 5hz and resend configuration
e) GPSGlitch acceptable radius reduced to 5m (stricter detection of glitches)
f) range check roll, pitch input to ensure crazy radio values don't get through to stabilize controller
6) bug fixes:
a) missing throttle controller initialisation would mean Stabilize mode's throttle could be non-tilt-compensated
b) inertial nav baro and gps delay compensation fix (contribution from Neurocopter)
c) GPS failsafe was invoking LAND mode which still used GPS for horizontal control
1) GPS Glitch protection - gps positions are compared with the previous gps position. Position accepted if within 10m or copter could have reached the position with max accel of 10m/s/s.
2) Bug fix for pixhawk SPI bus contention that could lead to corrupted accelerometer values on pixhawk resolved
3) Auto Tuning (compile time option only add "#define AUTOTUNE ENABLED" to APM_Config.h and set CH7_Opt or CH8_Opt parameter to 17)
4) CPU Performance improvement when reading from MPU6k for APM
5) SUPER_SIMPLE parameter changed to a bit map to allow some flight modes to use super simpler while others use regular simple (MP release to allow easier selection will go out with AC3.1 official release)
6) Safety changes:
a) safety button must be pushed before arming on pixhawk
b) RGB LED (aka toshiba led) changed so that disarmed flashes, armed is either blue (if no gps lock) or green (if gps lock)
1) Inertial navigation for X & Y axis (Randy/Leonard/Jonathan)
2) 3D waypoint navigation library (Leonard/Randy)
WPNAV_SPEED, WPNAV_SPEED_UP, WPNAV_SPEED_DN control target speeds during missions and RTL
WP_YAW_BEHAVIOR to allow disabling yaw during missions and RTL
3) PX4 support (some features still not available) (Tridge/Pat/PX4Dev Team)
4) Safety improvements:
Tin-can shaped fence (set FENCE_ENABLED to 1 and copter will RTL if alt > 150m or horizontal distance from home > 300m) (Randy/Tridge/Leonard)
GCS failsafe (set FS_GCS_ENABLED to 1 and if you are using a tablet to fly your copter it will RTL and return control to the radio 3 seconds after losing telemetry) (Randy)
pre-arm checks to ensure accelerometer and radio calibration has been performed before arming (Randy)
5) motor interference compensation for compass (Jonathan/Randy)
6) Circle mode improvements:
set CIRCLE_RADIUS to zero to do panorama shots in circle mode (copter does not move in a circle but instead slowly rotates)
CIRCLE_RATE parameter allows controlling direction and speed of rotation in CIRCLE mode and LOITER_TURNS (can also be adjusted in flight from CH6 knob)
7) SONAR_GAIN parameter add to allow reducing the response to objects sensed by sonar (Randy)
8) support for trapezoidal quads (aka V shaped or FPV quads) (Leonard/Craig)
9) performance improvements to dataflash logging (Tridge)
10) bug-fix to analog read which could cause bad sonar reads when using voltage or current monitor (Tridge)
11) bug-fix to motors going to minimum when throttle is low while switching into Loiter, AUTO, RTL, ALT_HOLD (Jason/Randy)
12) bug-fix for auto disarm sometimes disarming shortly after arming (Jason/SirAlex)
- 430 bytes of RAM freed up to resolve APM1 level issue and reduce chance of memory corruption on both APM1 and APM2
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)
Bug Fixes / Parameter changes:
- 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)
Code Cleanup:
- HAL changes for platform portability (Pat Hickey)
