Merge pull request #931 from PX4/fwtrim

fw att control: manual setpoint: fix comment and trim sign

src/modules/fw_att_control/fw_att_control_main.cpp

@@ -706,19 +706,20 @@ FixedwingAttitudeControl::task_main()
 				} else {
 					/*
 					 * Scale down roll and pitch as the setpoints are radians
-					 * and a typical remote can only do 45 degrees, the mapping is
-					 * -1..+1 to -45..+45 degrees or -0.75..+0.75 radians.
+					 * and a typical remote can only do around 45 degrees, the mapping is
+					 * -1..+1 to -man_roll_max rad..+man_roll_max rad (equivalent for pitch)
 					 *
 					 * With this mapping the stick angle is a 1:1 representation of
-					 * the commanded attitude. If more than 45 degrees are desired,
-					 * a scaling parameter can be applied to the remote.
+					 * the commanded attitude.
 					 *
 					 * The trim gets subtracted here from the manual setpoint to get
 					 * the intended attitude setpoint. Later, after the rate control step the
 					 * trim is added again to the control signal.
 					 */
-					roll_sp = (_manual.roll * _parameters.man_roll_max - _parameters.trim_roll) + _parameters.rollsp_offset_rad;
-					pitch_sp = (-_manual.pitch * _parameters.man_pitch_max - _parameters.trim_pitch) + _parameters.pitchsp_offset_rad;
+					roll_sp = (_manual.roll * _parameters.man_roll_max - _parameters.trim_roll)
+						+ _parameters.rollsp_offset_rad;
+					pitch_sp = -(_manual.pitch * _parameters.man_pitch_max - _parameters.trim_pitch)
+						+ _parameters.pitchsp_offset_rad;
 					throttle_sp = _manual.throttle;
 					_actuators.control[4] = _manual.flaps;