FW Rate Controller: allow to enable/disable yaw axis in Acro (#21566)

* RateControl: rename setGains to setPidGains to be more precise

Signed-off-by: Silvan Fuhrer <silvan@auterion.com>

* FW Rate controller: only allow to disable Yaw in Acro, not roll and pitch

Signed-off-by: Silvan Fuhrer <silvan@auterion.com>

---------

Signed-off-by: Silvan Fuhrer <silvan@auterion.com>

src/lib/rate_control/rate_control.cpp

@@ -1,6 +1,6 @@
 /****************************************************************************
  *
- *   Copyright (c) 2019 PX4 Development Team. All rights reserved.
+ *   Copyright (c) 2019-2023 PX4 Development Team. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -40,7 +40,7 @@
 
 using namespace matrix;
 
-void RateControl::setGains(const Vector3f &P, const Vector3f &I, const Vector3f &D)
+void RateControl::setPidGains(const Vector3f &P, const Vector3f &I, const Vector3f &D)
 {
 	_gain_p = P;
 	_gain_i = I;

src/lib/rate_control/rate_control.hpp

@@ -1,6 +1,6 @@
 /****************************************************************************
  *
- *   Copyright (c) 2019 PX4 Development Team. All rights reserved.
+ *   Copyright (c) 2019-2023 PX4 Development Team. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -51,12 +51,12 @@ public:
 	~RateControl() = default;
 
 	/**
-	 * Set the rate control gains
+	 * Set the rate control PID gains
 	 * @param P 3D vector of proportional gains for body x,y,z axis
 	 * @param I 3D vector of integral gains
 	 * @param D 3D vector of derivative gains
 	 */
-	void setGains(const matrix::Vector3f &P, const matrix::Vector3f &I, const matrix::Vector3f &D);
+	void setPidGains(const matrix::Vector3f &P, const matrix::Vector3f &I, const matrix::Vector3f &D);
 
 	/**
 	 * Set the mximum absolute value of the integrator for all axes
@@ -94,6 +94,18 @@ public:
 	 */
 	void resetIntegral() { _rate_int.zero(); }
 
+	/**
+	 * Set the integral term to 0 for specific axes
+	 * @param  axis roll 0 / pitch 1 / yaw 2
+	 * @see _rate_int
+	 */
+	void resetIntegral(size_t axis)
+	{
+		if (axis < 3) {
+			_rate_int(axis) = 0.f;
+		}
+	}
+
 	/**
 	 * Get status message of controller for logging/debugging
 	 * @param rate_ctrl_status status message to fill with internal states

src/modules/fw_rate_control/FixedwingRateControl.cpp

@@ -77,7 +77,7 @@ FixedwingRateControl::parameters_update()
 	const Vector3f rate_i = Vector3f(_param_fw_rr_i.get(), _param_fw_pr_i.get(), _param_fw_yr_i.get());
 	const Vector3f rate_d = Vector3f(_param_fw_rr_d.get(), _param_fw_pr_d.get(), _param_fw_yr_d.get());
 
-	_rate_control.setGains(rate_p, rate_i, rate_d);
+	_rate_control.setPidGains(rate_p, rate_i, rate_d);
 
 	_rate_control.setIntegratorLimit(
 		Vector3f(_param_fw_rr_imax.get(), _param_fw_pr_imax.get(), _param_fw_yr_imax.get()));
@@ -335,27 +335,36 @@ void FixedwingRateControl::Run()
 					body_rates_setpoint = Vector3f(-_rates_sp.yaw, _rates_sp.pitch, _rates_sp.roll);
 				}
 
-				/* Run attitude RATE controllers which need the desired attitudes from above, add trim */
+				// Run attitude RATE controllers which need the desired attitudes from above, add trim.
 				const Vector3f angular_acceleration_setpoint = _rate_control.update(rates, body_rates_setpoint, angular_accel, dt,
 						_landed);
 
-				float roll_feedforward = _param_fw_rr_ff.get() * _airspeed_scaling * body_rates_setpoint(0);
+				const float roll_feedforward = _param_fw_rr_ff.get() * _airspeed_scaling * body_rates_setpoint(0);
-				float roll_u = angular_acceleration_setpoint(0) * _airspeed_scaling * _airspeed_scaling + roll_feedforward;
+				const float pitch_feedforward = _param_fw_pr_ff.get() * _airspeed_scaling * body_rates_setpoint(1);
-				_vehicle_torque_setpoint.xyz[0] = PX4_ISFINITE(roll_u) ? math::constrain(roll_u + trim_roll, -1.f, 1.f) : trim_roll;
-
-				float pitch_feedforward = _param_fw_pr_ff.get() * _airspeed_scaling * body_rates_setpoint(1);
-				float pitch_u = angular_acceleration_setpoint(1) * _airspeed_scaling * _airspeed_scaling + pitch_feedforward;
-				_vehicle_torque_setpoint.xyz[1] = PX4_ISFINITE(pitch_u) ? math::constrain(pitch_u + trim_pitch, -1.f, 1.f) : trim_pitch;
-
 				const float yaw_feedforward = _param_fw_yr_ff.get() * _airspeed_scaling * body_rates_setpoint(2);
-				float yaw_u = angular_acceleration_setpoint(2) * _airspeed_scaling * _airspeed_scaling + yaw_feedforward;
 
-				_vehicle_torque_setpoint.xyz[2] = PX4_ISFINITE(yaw_u) ? math::constrain(yaw_u + trim_yaw, -1.f, 1.f) : trim_yaw;
+				const float roll_u = angular_acceleration_setpoint(0) * _airspeed_scaling * _airspeed_scaling + roll_feedforward;
+				const float pitch_u = angular_acceleration_setpoint(1) * _airspeed_scaling * _airspeed_scaling + pitch_feedforward;
+
+				// Special case yaw in Acro: if the parameter FW_ACRO_YAW_CTL is not set then don't control yaw
+				float yaw_u = 0.f;
+
+				if (_vcontrol_mode.flag_control_attitude_enabled || _param_fw_acro_yaw_en.get()) {
+					yaw_u = angular_acceleration_setpoint(2) * _airspeed_scaling * _airspeed_scaling + yaw_feedforward;
+
+				} else {
+					yaw_u = _manual_control_setpoint.yaw * _param_fw_man_y_sc.get();
+					_rate_control.resetIntegral(2);
+				}
 
 				if (!PX4_ISFINITE(roll_u) || !PX4_ISFINITE(pitch_u) || !PX4_ISFINITE(yaw_u)) {
 					_rate_control.resetIntegral();
 				}
 
+				_vehicle_torque_setpoint.xyz[0] = PX4_ISFINITE(roll_u) ? math::constrain(roll_u + trim_roll, -1.f, 1.f) : trim_roll;
+				_vehicle_torque_setpoint.xyz[1] = PX4_ISFINITE(pitch_u) ? math::constrain(pitch_u + trim_pitch, -1.f, 1.f) : trim_pitch;
+				_vehicle_torque_setpoint.xyz[2] = PX4_ISFINITE(yaw_u) ? math::constrain(yaw_u + trim_yaw, -1.f, 1.f) : trim_yaw;
+
 				/* throttle passed through if it is finite */
 				_vehicle_thrust_setpoint.xyz[0] = PX4_ISFINITE(_rates_sp.thrust_body[0]) ? _rates_sp.thrust_body[0] : 0.0f;
 

src/modules/fw_rate_control/FixedwingRateControl.hpp

@@ -148,6 +148,7 @@ private:
 		(ParamFloat<px4::params::FW_ACRO_X_MAX>) _param_fw_acro_x_max,
 		(ParamFloat<px4::params::FW_ACRO_Y_MAX>) _param_fw_acro_y_max,
 		(ParamFloat<px4::params::FW_ACRO_Z_MAX>) _param_fw_acro_z_max,
+		(ParamInt<px4::params::FW_ACRO_YAW_EN>) _param_fw_acro_yaw_en,
 
 		(ParamFloat<px4::params::FW_AIRSPD_MAX>) _param_fw_airspd_max,
 		(ParamFloat<px4::params::FW_AIRSPD_MIN>) _param_fw_airspd_min,

src/modules/fw_rate_control/fw_rate_control_params.c

@@ -537,3 +537,16 @@ PARAM_DEFINE_FLOAT(FW_RLL_TO_YAW_FF, 0.0f);
  * @group FW Attitude Control
  */
 PARAM_DEFINE_INT32(FW_SPOILERS_MAN, 0);
+
+/**
+ * Enable yaw rate controller in Acro
+ *
+ * If this parameter is set to 1, the yaw rate controller is enabled in Fixed-wing Acro mode.
+ * Otherwise the pilot commands directly the yaw actuator.
+ * It is disabled by default because an active yaw rate controller will fight against the
+ * natural turn coordination of the plane.
+ *
+ * @boolean
+ * @group FW Rate Control
+ */
+PARAM_DEFINE_INT32(FW_ACRO_YAW_EN, 0);

src/modules/mc_rate_control/MulticopterRateControl.cpp

@@ -80,7 +80,7 @@ MulticopterRateControl::parameters_updated()
 	// to the ideal (K * [1 + 1/sTi + sTd]) form
 	const Vector3f rate_k = Vector3f(_param_mc_rollrate_k.get(), _param_mc_pitchrate_k.get(), _param_mc_yawrate_k.get());
 
-	_rate_control.setGains(
+	_rate_control.setPidGains(
 		rate_k.emult(Vector3f(_param_mc_rollrate_p.get(), _param_mc_pitchrate_p.get(), _param_mc_yawrate_p.get())),
 		rate_k.emult(Vector3f(_param_mc_rollrate_i.get(), _param_mc_pitchrate_i.get(), _param_mc_yawrate_i.get())),
 		rate_k.emult(Vector3f(_param_mc_rollrate_d.get(), _param_mc_pitchrate_d.get(), _param_mc_yawrate_d.get())));