MC acro: add separate params to configure yaw expo

So that it can be customized better according to personal preferences.

The limitation of 16 chars did not allow to use a better param name.

src/modules/mc_att_control/mc_att_control.hpp

@@ -220,8 +220,10 @@ private:
 		(ParamFloat<px4::params::MC_ACRO_R_MAX>) _acro_roll_max,
 		(ParamFloat<px4::params::MC_ACRO_P_MAX>) _acro_pitch_max,
 		(ParamFloat<px4::params::MC_ACRO_Y_MAX>) _acro_yaw_max,
-		(ParamFloat<px4::params::MC_ACRO_EXPO>) _acro_expo,				/**< function parameter for expo stick curve shape */
+		(ParamFloat<px4::params::MC_ACRO_EXPO>) _acro_expo_rp,				/**< expo stick curve shape (roll & pitch) */
-		(ParamFloat<px4::params::MC_ACRO_SUPEXPO>) _acro_superexpo,			/**< function parameter for superexpo stick curve shape */
+		(ParamFloat<px4::params::MC_ACRO_EXPO_Y>) _acro_expo_y,				/**< expo stick curve shape (yaw) */
+		(ParamFloat<px4::params::MC_ACRO_SUPEXPO>) _acro_superexpo_rp,			/**< superexpo stick curve shape (roll & pitch) */
+		(ParamFloat<px4::params::MC_ACRO_SUPEXPOY>) _acro_superexpo_y,			/**< superexpo stick curve shape (yaw) */
 
 		(ParamFloat<px4::params::MC_RATT_TH>) _rattitude_thres,
 

src/modules/mc_att_control/mc_att_control_main.cpp

@@ -704,9 +704,9 @@ MulticopterAttitudeControl::run()
 				if (_v_control_mode.flag_control_manual_enabled) {
 					/* manual rates control - ACRO mode */
 					Vector3f man_rate_sp(
-							math::superexpo(_manual_control_sp.y, _acro_expo.get(), _acro_superexpo.get()),
+							math::superexpo(_manual_control_sp.y, _acro_expo_rp.get(), _acro_superexpo_rp.get()),
-							math::superexpo(-_manual_control_sp.x, _acro_expo.get(), _acro_superexpo.get()),
+							math::superexpo(-_manual_control_sp.x, _acro_expo_rp.get(), _acro_superexpo_rp.get()),
-							math::superexpo(_manual_control_sp.r, _acro_expo.get(), _acro_superexpo.get()));
+							math::superexpo(_manual_control_sp.r, _acro_expo_y.get(), _acro_superexpo_y.get()));
 					_rates_sp = man_rate_sp.emult(_acro_rate_max);
 					_thrust_sp = _manual_control_sp.z;
 

src/modules/mc_att_control/mc_att_control_params.c

@@ -381,8 +381,7 @@ PARAM_DEFINE_FLOAT(MC_ACRO_P_MAX, 720.0f);
 PARAM_DEFINE_FLOAT(MC_ACRO_Y_MAX, 540.0f);
 
 /**
- * Acro Expo factor
+ * Acro Expo factor for Roll and Pitch.
- * applied to input of all axis: roll, pitch, yaw
  *
  * 0 Purely linear input curve
  * 1 Purely cubic input curve
@@ -395,8 +394,20 @@ PARAM_DEFINE_FLOAT(MC_ACRO_Y_MAX, 540.0f);
 PARAM_DEFINE_FLOAT(MC_ACRO_EXPO, 0.69f);
 
 /**
- * Acro SuperExpo factor
+ * Acro Expo factor for Yaw.
- * applied to input of all axis: roll, pitch, yaw
+ *
+ * 0 Purely linear input curve
+ * 1 Purely cubic input curve
+ *
+ * @min 0
+ * @max 1
+ * @decimal 2
+ * @group Multicopter Attitude Control
+ */
+PARAM_DEFINE_FLOAT(MC_ACRO_EXPO_Y, 0.69f);
+
+/**
+ * Acro SuperExpo factor for Roll and Pitch.
  *
  * 0 Pure Expo function
  * 0.7 resonable shape enhancement for intuitive stick feel
@@ -409,6 +420,20 @@ PARAM_DEFINE_FLOAT(MC_ACRO_EXPO, 0.69f);
  */
 PARAM_DEFINE_FLOAT(MC_ACRO_SUPEXPO, 0.7f);
 
+/**
+ * Acro SuperExpo factor for Yaw.
+ *
+ * 0 Pure Expo function
+ * 0.7 resonable shape enhancement for intuitive stick feel
+ * 0.95 very strong bent input curve only near maxima have effect
+ *
+ * @min 0
+ * @max 0.95
+ * @decimal 2
+ * @group Multicopter Attitude Control
+ */
+PARAM_DEFINE_FLOAT(MC_ACRO_SUPEXPOY, 0.7f);
+
 /**
  * Threshold for Rattitude mode
  *