Add dual motor mixer

Author: Jaeyoung-Lim

ROMFS/px4fmu_common/init.d/airframes/22003_asl_believer

@@ -46,7 +46,7 @@ param set-default PWM_MAIN_DISARM 1000
 # The Mini Talon does not have a wheel and
 # no flaps. I leave them here because the mixer
 # computes also wheel and flap controls.
-set MIXER AAVVTWFF_vtail
+set MIXER AAVVTTFF_vtail
 
 # use PWM parameters for throttle channel
 set PWM_OUT 5

ROMFS/px4fmu_common/mixers/AAVVTTFF_vtail.main.mix

@@ -0,0 +1,61 @@
+Aileron/v-tail/throttle/wheel/flaps mixer for PX4FMU
+=======================================================
+
+This file defines mixers suitable for controlling a fixed wing aircraft with
+aileron, v-tail (rudder, elevator), throttle, steerable wheel and flaps
+using PX4FMU.
+The configuration assumes the aileron servos are connected to PX4FMU servo
+output 0 and 1, the tail servos to output 2 and 3, the throttle
+to output 4, the wheel to output 5 and the flaps to output 6 and 7.
+
+Inputs to the mixer come from channel group 0 (vehicle attitude), channels 0
+(roll), 1 (pitch), 2 (yaw) and 3 (thrust) 4 (flaps) 6 (flaperon).
+
+Aileron mixer (roll + flaperon)
+---------------------------------
+
+This mixer assumes that the aileron servos are set up mechanically reversed.
+
+M: 2
+S: 0 0 -10000 -10000      0 -10000  10000
+S: 0 6  10000  10000      0 -10000  10000
+
+M: 2
+S: 0 0 -10000 -10000      0 -10000  10000
+S: 0 6 -10000 -10000      0 -10000  10000
+
+V-tail mixers
+-------------
+Three scalers total (output, roll, pitch).
+
+M: 2
+S: 0 2   7000   7000      0 -10000  10000
+S: 0 1  -8000  -8000      0 -10000  10000
+
+M: 2
+S: 0 2   7000   7000      0 -10000  10000
+S: 0 1   8000   8000      0 -10000  10000
+
+Motor speed mixer
+-----------------
+Two scalers total (output, thrust).
+
+This mixer generates a full-range output (-1 to 1) from an input in the (0 - 1)
+range.  Inputs below zero are treated as zero.
+
+M: 1
+S: 0 3      0  20000 -10000 -10000  10000
+
+M: 1
+S: 0 3      0  20000 -10000 -10000  10000
+
+Flaps mixer
+------------
+Flap servos are physically reversed.
+
+M: 1
+S: 0 4      0   5000 -10000 -10000  10000
+
+M: 1
+S: 0 4      0  -5000  10000 -10000  10000
+

ROMFS/px4fmu_common/mixers/CMakeLists.txt

@@ -35,6 +35,7 @@ px4_add_romfs_files(
 	AAERTWF.main.mix
 	AAVVTWFF.main.mix
 	AAVVTWFF_vtail.main.mix
+	AAVVTTFF_vtail.main.mix
 	AERT.main.mix
 	AETRFG.main.mix
 	babyshark.main.mix