ArduPlane: add RC option for landing flare

ArduPlane/Attitude.cpp

@@ -123,6 +123,12 @@ void Plane::stabilize_pitch(float speed_scaler)
     if (control_mode == &mode_stabilize && channel_pitch->get_control_in() != 0) {
         disable_integrator = true;
     }
+
+   // if LANDING_FLARE RCx_OPTION switch is set and in FW mode, manual throttle,throttle idle then set pitch to LAND_PITCH_CD
+   if (!quadplane.in_transition() && !control_mode->is_vtol_mode() && channel_throttle->in_trim_dz() && !auto_throttle_mode && flare_switch_active) {
+       demanded_pitch = landing.get_pitch_cd();
+   }
+
     SRV_Channels::set_output_scaled(SRV_Channel::k_elevator, pitchController.get_servo_out(demanded_pitch - ahrs.pitch_sensor, 
                                                                                            speed_scaler, 
                                                                                            disable_integrator));

ArduPlane/Plane.h

@@ -1050,6 +1050,7 @@ private:
     void servos_output(void);
     void servos_auto_trim(void);
     void servos_twin_engine_mix();
+    void force_flare();
     void throttle_voltage_comp(int8_t &min_throttle, int8_t &max_throttle);
     void throttle_watt_limiter(int8_t &min_throttle, int8_t &max_throttle);
     void throttle_slew_limit(SRV_Channel::Aux_servo_function_t func);
@@ -1128,6 +1129,8 @@ private:
 
     CrowMode crow_mode = CrowMode::NORMAL;
 
+    bool flare_switch_active;
+
 public:
     void failsafe_check(void);
     bool set_target_location(const Location& target_loc) override;

ArduPlane/RC_Channel.cpp

@@ -116,6 +116,23 @@ void RC_Channel_Plane::do_aux_function_soaring_3pos(AuxSwitchPos ch_flag)
     plane.g2.soaring_controller.set_pilot_desired_state(desired_state);
 #endif
 }
+
+void RC_Channel_Plane::do_aux_function_flare(AuxSwitchPos ch_flag)
+{
+        switch(ch_flag) {
+        case AuxSwitchPos::HIGH:
+            plane.flare_switch_active = true;
+            plane.quadplane.set_q_assist_state(plane.quadplane.Q_ASSIST_STATE_ENUM::Q_ASSIST_DISABLED);
+            break;
+        case AuxSwitchPos::MIDDLE:
+            break;
+        case AuxSwitchPos::LOW:
+            plane.quadplane.set_q_assist_state(plane.quadplane.Q_ASSIST_STATE_ENUM::Q_ASSIST_ENABLED);
+            plane.flare_switch_active = false;
+            break;
+        }    
+}
+
 void RC_Channel_Plane::init_aux_function(const RC_Channel::aux_func_t ch_option,
                                          const RC_Channel::AuxSwitchPos ch_flag)
 {
@@ -131,6 +148,7 @@ void RC_Channel_Plane::init_aux_function(const RC_Channel::aux_func_t ch_option,
     case AUX_FUNC::RTL:
     case AUX_FUNC::TAKEOFF:
     case AUX_FUNC::FWD_THR:
+    case AUX_FUNC::LANDING_FLARE:
         break;
 
     case AUX_FUNC::Q_ASSIST:
@@ -257,6 +275,10 @@ void RC_Channel_Plane::do_aux_function(const aux_func_t ch_option, const AuxSwit
         }
         break;
 
+   case AUX_FUNC::LANDING_FLARE:
+       do_aux_function_flare(ch_flag);
+       break;
+
     default:
         RC_Channel::do_aux_function(ch_option, ch_flag);
         break;

ArduPlane/RC_Channel.h

@@ -23,6 +23,9 @@ private:
     void do_aux_function_crow_mode(AuxSwitchPos ch_flag);
 
     void do_aux_function_soaring_3pos(AuxSwitchPos ch_flag);
+
+    void do_aux_function_flare(AuxSwitchPos ch_flag);
+
 };
 
 class RC_Channels_Plane : public RC_Channels

ArduPlane/servos.cpp

@@ -727,9 +727,35 @@ void Plane::servos_twin_engine_mix(void)
     }
 }
 
-
 /*
-  Set the flight control servos based on the current calculated values
+  Set throttle,attitude(in Attitude.cpp), and tilt servos for forced flare by RCx_OPTION switch for landing in FW mode
+  For Fixed Wind modes with manual throttle control only. Forces tilts up and throttle to THR_MIN.
+  Throttle stick must be in idle deadzone. This allows non-momentary switch to be used and quick bailouts
+  for go-arounds. Also helps prevent propstrike after landing with switch release on ground.
+*/
+void Plane::force_flare(void)
+{
+    if (!quadplane.in_transition() && !control_mode->is_vtol_mode() && !auto_throttle_mode && channel_throttle->in_trim_dz() && flare_switch_active) {
+        int32_t tilt = -SERVO_MAX;  //this is tilts up for a normal tiltrotor
+        if (quadplane.tilt.tilt_type == QuadPlane::TILT_TYPE_BICOPTER) {
+            tilt = 0; // this is tilts up for a Bicopter
+        }
+        if (quadplane.is_tailsitter()) {
+            tilt = SERVO_MAX; //this is tilts up for a tailsitter
+        }
+        SRV_Channels::set_output_scaled(SRV_Channel::k_motor_tilt, tilt);
+        SRV_Channels::set_output_scaled(SRV_Channel::k_tiltMotorLeft, tilt);
+        SRV_Channels::set_output_scaled(SRV_Channel::k_tiltMotorRight, tilt);
+        float throttle_min = MAX(aparm.throttle_min.get(),0); //allows ICE to run if used but accounts for reverse thrust setups
+        if (arming.is_armed()) {  //prevent running motors if unarmed
+            SRV_Channels::set_output_scaled(SRV_Channel::k_throttle, throttle_min);
+            SRV_Channels::set_output_scaled(SRV_Channel::k_throttleLeft, throttle_min);
+            SRV_Channels::set_output_scaled(SRV_Channel::k_throttleRight, throttle_min);
+        }
+     }
+}
+
+/* Set the flight control servos based on the current calculated values
 
   This function operates by first building up output values for
   channels using set_servo() and set_radio_out(). Using
@@ -885,7 +911,6 @@ void Plane::set_servos(void)
     servos_output();
 }
 
-
 /*
   run configured output mixer. This takes calculated servo_out values
   for each channel and calculates PWM values, then pushes them to
@@ -902,6 +927,9 @@ void Plane::servos_output(void)
     quadplane.tailsitter_output();
     quadplane.tiltrotor_bicopter();
 
+    // support forced flare option
+    force_flare();
+ 
     // run vtail and elevon mixers
     servo_output_mixers();