Ice shedding: expose configuration parameters

src/modules/control_allocator/ControlAllocator.cpp

@@ -649,19 +649,19 @@ ControlAllocator::publish_control_allocator_status(int matrix_index)
 float
 ControlAllocator::get_ice_shedding_output(hrt_abstime now)
 {
+	const float period_sec = _param_ice_shedding_period.get();
+	const float on_sec = _param_ice_shedding_on_time.get();
+	const float max_ice_shedding_output = _param_ice_shedding_output.get();
 
-	// Feature config
-	const bool spin_to_shed_enabled = true; // TODO replace by param
-
-	const float period_sec = 10.0f;
-	const float on_sec = 5.0f;
-	const float slew_sec = 1.0f; // Time to reach full shed_ice_thrust
-	const float max_ice_shedding_output = 0.1f;
+	if (period_sec <= FLT_EPSILON || on_sec <= FLT_EPSILON || max_ice_shedding_output <= FLT_EPSILON) {
+		// The user has not configured the feature to be turned on
+		return 0.0f;
+	}
 
 	const bool has_unused_upwards_rotors = _effectiveness_source_id == EffectivenessSource::STANDARD_VTOL
 					       || _effectiveness_source_id == EffectivenessSource::TILTROTOR_VTOL;
 	const bool in_forward_flight = _actuator_effectiveness->getFlightPhase() == ActuatorEffectiveness::FlightPhase::FORWARD_FLIGHT;
-	const bool apply_shedding = has_unused_upwards_rotors && spin_to_shed_enabled && in_forward_flight;
+	const bool apply_shedding = has_unused_upwards_rotors && in_forward_flight;
 
 	if (!apply_shedding) {
 		return 0.0f;
@@ -671,6 +671,16 @@ ControlAllocator::get_ice_shedding_output(hrt_abstime now)
 
 	float current_ice_shedding_output = 0.0f;
 
+	const float slew_sec = 1.0f; // Time to reach full shed_ice_thrust
+
+	// TOOD ensure this works (fails predictably...) when on_sec < 2 * slew_sec
+	// TODO if period_sec > on_sec, always output thrust? still fade it in?
+	// TODO when the params are changed in flight we essentially enter the
+	// cycle in a completely random phase, bypassing the slew limit.
+	//  - find out if this is actually dangerous
+	//  - if so, put some offset that is updated on param changes to stay in the same phase
+	//  - or redo the entire implementation with a state machine rather than this pure functional version
+
 	if (elapsed_in_period < on_sec) {
 
 		// We are in the "active" window, calculate ramping

src/modules/control_allocator/ControlAllocator.hpp

@@ -220,7 +220,10 @@ private:
 		(ParamInt<px4::params::CA_AIRFRAME>) _param_ca_airframe,
 		(ParamInt<px4::params::CA_METHOD>) _param_ca_method,
 		(ParamInt<px4::params::CA_FAILURE_MODE>) _param_ca_failure_mode,
-		(ParamInt<px4::params::CA_R_REV>) _param_r_rev
+		(ParamInt<px4::params::CA_R_REV>) _param_r_rev,
+		(ParamFloat<px4::params::CA_ICE_PERIOD>) _param_ice_shedding_period,
+		(ParamFloat<px4::params::CA_ICE_ON_TIME>) _param_ice_shedding_on_time,
+		(ParamFloat<px4::params::CA_ICE_OUTPUT>) _param_ice_shedding_output
 	)
 
 };

src/modules/control_allocator/module.yaml

@@ -605,6 +605,53 @@ parameters:
                 1: Remove first failed motor from effectiveness
             default: 0
 
+        CA_ICE_PERIOD:
+            description:
+                short: Ice shedding cycle period
+                long: |
+                    Ice shedding is a feature that periodically spins unused
+                    upwards rotors on VTOL aircraft to remove ice buildup within
+                    the motors. This period defines the total duration of the
+                    ice shedding cycle.  Feature is turned off if <= 0.
+            type: float
+            decimal: 1
+            unit: s
+            increment: 0.1
+            min: 0.0
+            max: 300.0
+            default: 60.0
+
+        CA_ICE_ON_TIME:
+            description:
+                short: Ice shedding active duration
+                long: |
+                    This parameter defines the active duration within each ice
+                    shedding cycle during which rotors will spin. Feature is
+                    turned off if <= 0.
+            type: float
+            decimal: 1
+            unit: s
+            increment: 0.1
+            min: 0.0
+            max: 300.0
+            default: 0.0
+
+        CA_ICE_OUTPUT:
+            description:
+                short: Maximum motor output for ice shedding
+                long: |
+                    This parameter determines the maximum motor output commanded
+                    during ice shedding. Warning: If this output is too high,
+                    the feature disturbs with fixed wing rate control,
+                    especially on tiltrotorp. Start with very low values, only
+                    increase in small steps. Feature is turned off if <= 0.
+            type: float
+            decimal: 2
+            increment: 0.01
+            min: 0.0
+            max: 0.2
+            default: 0.0
+
 # Mixer
 mixer:
     actuator_types: