refactor(rate_control): replace gain compression template with setters (#28910)

Templating GainCompression3d on its parameter IDs made the compiler emit
every method twice on boards that build both the fixed-wing and the
multicopter rate controller, as each instantiation is a separate class.
Inlining does not remove the duplicate because update() is too large to
be inlined.

Make GainCompression3d a plain class configured through setters and let
each rate controller own its FW_GC_* or MC_GC_* parameters. This saves
1040 bytes of flash on px4_fmu-v6x_default with no change in behaviour.

Assisted-by: Claude:claude-opus-5-5

Signed-off-by: Andrea Bernasconi <andrea.bernasconi@auterion.com>

src/lib/rate_control/gain_compression.cpp

@@ -36,15 +36,12 @@
 using matrix::Vector3f;
 using namespace time_literals;
 
-template<px4::params ParamEnable, px4::params ParamGainMin>
-GainCompression3dT<ParamEnable, ParamGainMin>::GainCompression3dT(ModuleParams *parent) : ModuleParams(parent)
+GainCompression3d::GainCompression3d()
 {
-	updateParams();
 	_gain_compression_pub.advertise();
 }
 
-template<px4::params ParamEnable, px4::params ParamGainMin>
-void GainCompression3dT<ParamEnable, ParamGainMin>::reset()
+void GainCompression3d::reset()
 {
 	for (unsigned i = 0; i < 3; i++) {
 		_compression_gains[i].reset();
@@ -53,20 +50,16 @@ void GainCompression3dT<ParamEnable, ParamGainMin>::reset()
 	_gains.setOne();
 }
 
-template<px4::params ParamEnable, px4::params ParamGainMin>
-void GainCompression3dT<ParamEnable, ParamGainMin>::updateParams()
+void GainCompression3d::setCompressionGainMin(const float gain_min)
 {
-	ModuleParams::updateParams();
-
 	for (unsigned i = 0; i < 3; i++) {
-		_compression_gains[i].setCompressionGainMin(_param_gc_gain_min.get());
+		_compression_gains[i].setCompressionGainMin(gain_min);
 	}
 }
 
-template<px4::params ParamEnable, px4::params ParamGainMin>
-void GainCompression3dT<ParamEnable, ParamGainMin>::update(const Vector3f &input, const float dt)
+void GainCompression3d::update(const Vector3f &input, const float dt)
 {
-	if (!_param_gc_en.get()) {
+	if (!_enabled) {
 		reset();
 		return;
 	}
@@ -99,9 +92,6 @@ void GainCompression3dT<ParamEnable, ParamGainMin>::update(const Vector3f &input
 	}
 }
 
-template class GainCompression3dT<px4::params::FW_GC_EN, px4::params::FW_GC_GAIN_MIN>;
-template class GainCompression3dT<px4::params::MC_GC_EN, px4::params::MC_GC_GAIN_MIN>;
-
 float GainCompression::update(const float input, const float dt)
 {
 	if (!PX4_ISFINITE(input)) {

src/lib/rate_control/gain_compression.hpp

@@ -44,11 +44,12 @@
 #pragma once
 
 // PX4 includes
-#include <px4_platform_common/module_params.h>
+#include <drivers/drv_hrt.h>
 
 // Libraries
 #include <math.h>
 #include <lib/mathlib/math/filter/AlphaFilter.hpp>
+#include <matrix/matrix/math.hpp>
 
 // uORB includes
 #include <uORB/Publication.hpp>
@@ -93,25 +94,18 @@ private:
 
 };
 
-/*
- * Templated on the enable and minimum gain parameter IDs so that the same
- * implementation can be used by the fixed-wing and multicopter rate controllers
- * with their own set of parameters.
- */
-template<px4::params ParamEnable, px4::params ParamGainMin>
-class GainCompression3dT : public ModuleParams
+class GainCompression3d
 {
 public:
-	GainCompression3dT(ModuleParams *parent);
-	~GainCompression3dT() = default;
+	GainCompression3d();
+	~GainCompression3d() = default;
 
 	void reset();
 	void update(const matrix::Vector3f &input, float dt);
 	const matrix::Vector3f &getGains() const { return _gains; };
 
-
-protected:
-	void updateParams() override;
+	void setEnabled(bool enabled) { _enabled = enabled; }
+	void setCompressionGainMin(float gain_min);
 
 private:
 	// uORB publications
@@ -120,16 +114,10 @@ private:
 	GainCompression _compression_gains[3];
 	matrix::Vector3f _gains{1.f, 1.f, 1.f};
 
+	bool _enabled{false};
+
 	hrt_abstime _time_last_publication{0};
 
 	static constexpr float _kLpfCutoffFrequency{5.f}; // Just above the control bandwidth of most UAVs
 	static constexpr float _kHpfCutoffFrequency{2.f * _kLpfCutoffFrequency}; // 1 Octave above LPF cutoff, as recommended by the reference paper
-
-	DEFINE_PARAMETERS(
-		(ParamBool<ParamEnable>) _param_gc_en,
-		(ParamFloat<ParamGainMin>) _param_gc_gain_min
-	)
 };
-
-using GainCompression3d = GainCompression3dT<px4::params::FW_GC_EN, px4::params::FW_GC_GAIN_MIN>;
-using GainCompression3dMc = GainCompression3dT<px4::params::MC_GC_EN, px4::params::MC_GC_GAIN_MIN>;

src/modules/fw_rate_control/FixedwingRateControl.cpp

@@ -85,6 +85,9 @@ FixedwingRateControl::parameters_update()
 	_rate_control.setIntegratorLimit(
 		Vector3f(_param_fw_rr_imax.get(), _param_fw_pr_imax.get(), _param_fw_yr_imax.get()));
 
+	_gain_compression.setEnabled(_param_fw_gc_en.get());
+	_gain_compression.setCompressionGainMin(_param_fw_gc_gain_min.get());
+
 	if (_handle_param_vt_fw_difthr_en != PARAM_INVALID) {
 		param_get(_handle_param_vt_fw_difthr_en, &_param_vt_fw_difthr_en);
 	}

src/modules/fw_rate_control/FixedwingRateControl.hpp

@@ -186,6 +186,9 @@ private:
 		(ParamFloat<px4::params::FW_DTRIM_Y_VMAX>) _param_fw_dtrim_y_vmax,
 		(ParamFloat<px4::params::FW_DTRIM_Y_VMIN>) _param_fw_dtrim_y_vmin,
 
+		(ParamBool<px4::params::FW_GC_EN>) _param_fw_gc_en,
+		(ParamFloat<px4::params::FW_GC_GAIN_MIN>) _param_fw_gc_gain_min,
+
 		(ParamFloat<px4::params::FW_MAN_P_SC>) _param_fw_man_p_sc,
 		(ParamFloat<px4::params::FW_MAN_R_SC>) _param_fw_man_r_sc,
 		(ParamFloat<px4::params::FW_MAN_Y_SC>) _param_fw_man_y_sc,
@@ -218,7 +221,7 @@ private:
 	)
 
 	RateControl _rate_control; ///< class for rate control calculations
-	GainCompression3d _gain_compression{this};
+	GainCompression3d _gain_compression;
 
 	void updateActuatorControlsStatus(float dt);
 

src/modules/mc_rate_control/MulticopterRateControl.cpp

@@ -93,6 +93,9 @@ MulticopterRateControl::parameters_updated()
 	_rate_control.setFeedForwardGain(
 		Vector3f(_param_mc_rollrate_ff.get(), _param_mc_pitchrate_ff.get(), _param_mc_yawrate_ff.get()));
 
+	_gain_compression.setEnabled(_param_mc_gc_en.get());
+	_gain_compression.setCompressionGainMin(_param_mc_gc_gain_min.get());
+
 
 	// manual rate control acro mode rate limits
 	_acro_rate_max = Vector3f(radians(_param_mc_acro_r_max.get()), radians(_param_mc_acro_p_max.get()),

src/modules/mc_rate_control/MulticopterRateControl.hpp

@@ -94,7 +94,7 @@ private:
 	void updateActuatorControlsStatus(const vehicle_torque_setpoint_s &vehicle_torque_setpoint, float dt);
 
 	RateControl _rate_control; ///< class for rate control calculations
-	GainCompression3dMc _gain_compression{this}; ///< reduces the loop gain when an oscillation is detected
+	GainCompression3d _gain_compression; ///< reduces the loop gain when an oscillation is detected
 
 	uORB::Subscription _battery_status_sub{ORB_ID(battery_status)};
 	uORB::Subscription _control_allocator_status_sub{ORB_ID(control_allocator_status)};
@@ -167,6 +167,9 @@ private:
 		(ParamFloat<px4::params::MC_ACRO_SUPEXPO>) _param_mc_acro_supexpo,		/**< superexpo stick curve shape (roll & pitch) */
 		(ParamFloat<px4::params::MC_ACRO_SUPEXPOY>) _param_mc_acro_supexpoy,		/**< superexpo stick curve shape (yaw) */
 
-		(ParamBool<px4::params::MC_BAT_SCALE_EN>) _param_mc_bat_scale_en
+		(ParamBool<px4::params::MC_BAT_SCALE_EN>) _param_mc_bat_scale_en,
+
+		(ParamBool<px4::params::MC_GC_EN>) _param_mc_gc_en,
+		(ParamFloat<px4::params::MC_GC_GAIN_MIN>) _param_mc_gc_gain_min
 	)
 };