feat(actuators): Control Flaps from AUX channel (#26913)

* feat(rc): flaps via AUX channel

* docs(actuators): add flaps and spoilers from RC

Co-authored-by: Silvan Fuhrer <silvan@auterion.com>

* docs(actuators): Update docs/en/payloads/generic_actuator_control.md

Co-authored-by: Hamish Willee <hamishwillee@gmail.com>

* docs(actuators): move flaps setup docs

---------

Co-authored-by: Silvan Fuhrer <silvan@auterion.com>
Co-authored-by: Hamish Willee <hamishwillee@gmail.com>

docs/en/config/actuators.md

@@ -175,7 +175,7 @@ The fields are:
 
 #### Flap Scale and Spoiler Scale Configuration
 
-"Flap-control" and "Spoiler-control" are aerodynamic configurations that can either be commanded manually by the pilot (using RC, say), or are set automatically by the controller.
+"Flap-control" and "Spoiler-control" are aerodynamic configurations that can either be commanded manually by the pilot (using RC or a Joystick, say) (see [Flaps and Spoiler Control with Manual Control](#flaps-and-spoiler-control-with-manual-control)), or are set automatically by the controller.
 For example, a pilot or the landing system might engage "Spoiler-control" in order to reduce the airspeed before landing.
 
 The configurations are an _abstract_ way for the controller to tell the allocator how much it should adjust the aerodynamic properties of the wings relative to the "full flaps" or "full spoiler" configuration (between `[0,1]`, where "1" indicates the full range).
@@ -198,6 +198,20 @@ In the following example, the vehicle has two ailerons, one elevator, one rudder
   These are the elevator deflections added to compensate for the pitching moments generated by the flaps and spoiler actuators.
   In the case here the elevator would be deflected 0.3 up when the flaps are fully deployed to counteract the pitching down moment caused by the flaps.
 
+#### Flaps and Spoiler Control with Manual Control
+
+The preferred method to manually actuate spoilers and flaps is to map a manual control switch to an `AUX` output (see [Generic Actuator Control with RC](#generic-actuator-control-with-rc)), and then map that AUX output to the flap or spoiler function using [FW_FLAPS_MAN](../advanced_config/parameter_reference.md#FW_FLAPS_MAN) or [FW_SPOILERS_MAN](../advanced_config/parameter_reference.md#FW_SPOILERS_MAN).
+The source for the manual control can be RC or MAVLink.
+
+::: warning
+The following method is not recommended, and will be removed in a future release.
+If using it you should migrate to using the AUX-based method.
+
+It is also possible to define a flaps channel directly on the RC using [RC_MAP_FLAPS](../advanced_config/parameter_reference.md#RC_MAP_FLAPS).
+This channel can also be used to control the spoilers by setting [FW_SPOILERS_MAN](../advanced_config/parameter_reference.md#FW_SPOILERS_MAN) to `Flaps channel`.
+This method is not possible when the source for the manual control is MAVLink.
+:::
+
 #### Actuator Roll, Pitch, and Yaw Scaling
 
 ::: info

docs/en/payloads/generic_actuator_control.md

@@ -35,6 +35,7 @@ To map a particular RC channel to an output function `RC AUX n` (and hence it's
 For example, to control an actuator attached to AUX pin 3 (say) you would assign the output function `RC AUX 5` to the output `AUX3`.
 You could then use set the RC channel to control the `AUX3` output using `RC_MAP_AUX5`.
 
+
 ## Generic Actuator Control in Missions
 
 To use generic actuator control in a mission you must first [configure the outputs that you want to control using MAVLink](#generic-actuator-control-with-mavlink).

src/modules/fw_rate_control/FixedwingRateControl.cpp

@@ -469,9 +469,35 @@ void FixedwingRateControl::Run()
 			// Flaps control
 			float flaps_control = 0.f; // default to no flaps
 
-			/* map flaps by default to manual if valid */
-			if (PX4_ISFINITE(_manual_control_setpoint.flaps)) {
-				flaps_control = math::max(_manual_control_setpoint.flaps, 0.f); // do not consider negative switch settings
+			switch (_param_fw_flaps_man.get()) { 		// do not consider negative switch settings
+			case 0:
+				break;
+
+			case 1:
+				flaps_control = PX4_ISFINITE(_manual_control_setpoint.aux1) ? math::max(_manual_control_setpoint.aux1, 0.f) : 0.f;
+				break;
+
+			case 2:
+				flaps_control = PX4_ISFINITE(_manual_control_setpoint.aux2) ? math::max(_manual_control_setpoint.aux2, 0.f) : 0.f;
+				break;
+
+			case 3:
+				flaps_control = PX4_ISFINITE(_manual_control_setpoint.aux3) ? math::max(_manual_control_setpoint.aux3, 0.f) : 0.f;
+				break;
+
+			case 4:
+				flaps_control = PX4_ISFINITE(_manual_control_setpoint.aux4) ? math::max(_manual_control_setpoint.aux4, 0.f) : 0.f;
+				break;
+
+			case 5:
+				flaps_control = PX4_ISFINITE(_manual_control_setpoint.aux5) ? math::max(_manual_control_setpoint.aux5, 0.f) : 0.f;
+				break;
+
+			case 6:
+				flaps_control = PX4_ISFINITE(_manual_control_setpoint.flaps) ? math::max(_manual_control_setpoint.flaps, 0.f) : 0.f;
+				break;
+
+
 			}
 
 			normalized_unsigned_setpoint_s flaps_setpoint;
@@ -482,19 +508,29 @@ void FixedwingRateControl::Run()
 			// Spoilers control
 			float spoilers_control = 0.f; // default to no spoilers
 
-			switch (_param_fw_spoilers_man.get()) {
+			switch (_param_fw_spoilers_man.get()) {		// do not consider negative switch settings
 			case 0:
 				break;
 
 			case 1:
-				// do not consider negative switch settings
 				spoilers_control = PX4_ISFINITE(_manual_control_setpoint.flaps) ? math::max(_manual_control_setpoint.flaps, 0.f) : 0.f;
 				break;
 
 			case 2:
-				// do not consider negative switch settings
 				spoilers_control = PX4_ISFINITE(_manual_control_setpoint.aux1) ? math::max(_manual_control_setpoint.aux1, 0.f) : 0.f;
 				break;
+
+			case 3:
+				spoilers_control = PX4_ISFINITE(_manual_control_setpoint.aux2) ? math::max(_manual_control_setpoint.aux2, 0.f) : 0.f;
+				break;
+
+			case 4:
+				spoilers_control = PX4_ISFINITE(_manual_control_setpoint.aux3) ? math::max(_manual_control_setpoint.aux3, 0.f) : 0.f;
+				break;
+
+			case 5:
+				spoilers_control = PX4_ISFINITE(_manual_control_setpoint.aux4) ? math::max(_manual_control_setpoint.aux4, 0.f) : 0.f;
+				break;
 			}
 
 			normalized_unsigned_setpoint_s spoilers_setpoint;

src/modules/fw_rate_control/FixedwingRateControl.hpp

@@ -213,7 +213,8 @@ private:
 		(ParamFloat<px4::params::TRIM_ROLL>) _param_trim_roll,
 		(ParamFloat<px4::params::TRIM_YAW>) _param_trim_yaw,
 
-		(ParamInt<px4::params::FW_SPOILERS_MAN>) _param_fw_spoilers_man
+		(ParamInt<px4::params::FW_SPOILERS_MAN>) _param_fw_spoilers_man,
+		(ParamInt<px4::params::FW_FLAPS_MAN>) _param_fw_flaps_man
 	)
 
 	RateControl _rate_control; ///< class for rate control calculations

src/modules/fw_rate_control/fw_rate_control_params.yaml

@@ -326,6 +326,24 @@ parameters:
         0: Disabled
         1: Flaps channel
         2: Aux1
+        3: Aux2
+        4: Aux3
+        5: Aux4
+        6: Aux5
+      default: 0
+    FW_FLAPS_MAN:
+      description:
+        short: Flap input in manual flight
+        long: Chose source for manual setting of flaps in manual flight modes.
+      type: enum
+      values:
+        0: Disabled
+        1: Aux1
+        2: Aux2
+        3: Aux3
+        4: Aux4
+        5: Aux5
+        6: Flaps channel
       default: 0
     FW_ACRO_YAW_EN:
       description: