AP_Motors: make THR_LOW_COMP a variable instead of param

libraries/AP_Motors/AP_Motors_Class.cpp

@@ -53,12 +53,7 @@ const AP_Param::GroupInfo AP_Motors::var_info[] PROGMEM = {
     // @User: Advanced
     AP_GROUPINFO("YAW_HEADROOM", 6, AP_Motors, _yaw_headroom, AP_MOTORS_YAW_HEADROOM_DEFAULT),
 
-    // @Param: THR_LOW_CMP
-    // @DisplayName: Motor low throttle compensation
-    // @Description: Ratio controlling the max throttle output during competing requests of low throttle from the pilot (or autopilot) and higher throttle for attitude control
-    // @Values: 0.2:Favour Throttle Control, 0.5:Equal Weighting, 1:Favour Attitude Control
-    // @User: Advanced
-    AP_GROUPINFO("THR_LOW_CMP", 7, AP_Motors, _throttle_low_comp, AP_MOTORS_THR_LOW_CMP_DEFAULT),
+    // 7 was THR_LOW_CMP
 
     // @Param: THST_EXPO
     // @DisplayName: Thrust Curve Expo
@@ -113,6 +108,8 @@ AP_Motors::AP_Motors(RC_Channel& rc_roll, RC_Channel& rc_pitch, RC_Channel& rc_t
     _max_throttle(AP_MOTORS_DEFAULT_MAX_THROTTLE),
     _hover_out(AP_MOTORS_DEFAULT_MID_THROTTLE),
     _spin_when_armed_ramped(0),
+    _throttle_low_comp(AP_MOTORS_THR_LOW_CMP_DEFAULT),
+    _throttle_low_comp_desired(AP_MOTORS_THR_LOW_CMP_DEFAULT),
     _batt_voltage(0.0f),
     _batt_voltage_resting(0.0f),
     _batt_current(0.0f),

libraries/AP_Motors/AP_Motors_Class.h

@@ -237,7 +237,6 @@ protected:
     AP_Int16            _spin_when_armed;       // used to control whether the motors always spin when armed.  pwm value above radio_min
 
     AP_Int16            _yaw_headroom;          // yaw control is given at least this pwm range
-    AP_Float            _throttle_low_comp;     // mix between throttle and hover throttle for 0 to 1 and ratio above hover throttle for >1
     AP_Float            _thrust_curve_expo;     // curve used to linearize pwm to thrust conversion.  set to 0 for linear and 1 for second order approximation
     AP_Float            _thrust_curve_max;      // throttle which produces the maximum thrust.  (i.e. 0 ~ 1 ) of the full throttle range
     AP_Float            _batt_voltage_max;      // maximum voltage used to scale lift
@@ -255,6 +254,7 @@ protected:
     int16_t             _max_throttle;          // the maximum throttle to be sent to the motors (sometimes limited by slow start)
     int16_t             _hover_out;             // the estimated hover throttle as pct * 10 (i.e. 0 ~ 1000)
     int16_t             _spin_when_armed_ramped;// equal to _spin_when_armed parameter but slowly ramped up from zero
+    float               _throttle_low_comp;     // mix between throttle and hover throttle for 0 to 1 and ratio above hover throttle for >1
     float               _throttle_low_comp_desired; // desired throttle_low_comp value, actual throttle_low_comp is slewed towards this value over 1~2 seconds
 
     // battery voltage compensation variables