Test the vehicle type parameter usage

msg/rtl_flight_time.msg

@@ -1,5 +1,4 @@
 uint64 timestamp				# time since system start (microseconds)
 
-uint8 rtl_vehicle_type			# from the vehicle_status message
 float32 rtl_time_s				# how long in seconds will the RTL take
 float32 rtl_limit_fraction			# what fraction of the allowable RTL time would be taken

src/modules/navigator/RangeRTLTest.cpp

@@ -50,6 +50,38 @@ TEST(Navigator_and_RTL, compiles_woohoooo)
 	ASSERT_TRUE(_rtl_flight_time_sub.update());
 	auto msg = _rtl_flight_time_sub.get();
 	EXPECT_EQ(msg.rtl_time_s, 0);
+
+	// WHEN: we set the vehicle type to multirotor
+	v_status.vehicle_type =
+		n.get_vstatus()->vehicle_type = vehicle_status_s::VEHICLE_TYPE_ROTARY_WING;
+	float xy, z;
+	rtl.get_rtl_xy_z_speed(xy, z);
+
+	// THEN: the RTL speed should correspond to multirotor parameters
+	float xy_desired, z_desired;
+	param_get(param_handle(px4::params::MPC_XY_CRUISE), &xy_desired);
+	param_get(param_handle(px4::params::MPC_Z_VEL_MAX_DN), &z_desired);
+	EXPECT_FLOAT_EQ(xy, xy_desired);
+	EXPECT_FLOAT_EQ(z, z_desired);
+
+	// WHEN: it is a fixed wing
+	n.get_vstatus()->vehicle_type = vehicle_status_s::VEHICLE_TYPE_FIXED_WING;
+	rtl.get_rtl_xy_z_speed(xy, z);
+
+	// THEN: it should be fixed wing parameters
+	param_get(param_handle(px4::params::FW_AIRSPD_TRIM), &xy_desired);
+	param_get(param_handle(px4::params::FW_T_SINK_MIN), &z_desired);
+	EXPECT_FLOAT_EQ(xy, xy_desired);
+	EXPECT_FLOAT_EQ(z, z_desired);
+
+	// WHEN: it is rover
+	n.get_vstatus()->vehicle_type = vehicle_status_s::VEHICLE_TYPE_ROVER;
+	rtl.get_rtl_xy_z_speed(xy, z);
+
+	// THEN: it should be rover parameters, and z should just be large (no RTL time in Z -> high speed)
+	param_get(param_handle(px4::params::GND_SPEED_THR_SC), &xy_desired);
+	EXPECT_FLOAT_EQ(xy, xy_desired);
+	EXPECT_GT(z, 1000);
 }
 
 class RangeRTL_tth : public ::testing::Test

src/modules/navigator/rtl.cpp

@@ -230,16 +230,14 @@ void RTL::find_RTL_destination()
 		map_projection_project(&_projection_reference, global_position.lat, global_position.lon, &local_destination(0),
 				       &local_destination(1));
 
-		uint8_t vehicle_type = _navigator->get_vstatus()->vehicle_type;
 		float xy_speed, z_speed;
-		get_rtl_xy_z_speed(vehicle_type, xy_speed, z_speed);
+		get_rtl_xy_z_speed(xy_speed, z_speed);
 		float time_to_home_s = time_to_home(local_pos, local_destination, get_wind(), xy_speed, z_speed);
 
 		float rtl_flight_time_ratio = time_to_home_s / (60 * _param_rtl_flt_time.get());
 		rtl_flight_time_s rtl_flight_time;
 		rtl_flight_time.rtl_limit_fraction = rtl_flight_time_ratio;
 		rtl_flight_time.rtl_time_s = time_to_home_s;
-		rtl_flight_time.rtl_vehicle_type = vehicle_type;
 		_rtl_flight_time_pub.publish(rtl_flight_time);
 	}
 }
@@ -642,8 +640,9 @@ float RTL::calculate_return_alt_from_cone_half_angle(float cone_half_angle_deg)
 	return max(return_altitude_amsl, gpos.alt);
 }
 
-void RTL::get_rtl_xy_z_speed(uint8_t vehicle_type, float &xy, float &z)
+void RTL::get_rtl_xy_z_speed(float &xy, float &z)
 {
+	uint8_t vehicle_type = _navigator->get_vstatus()->vehicle_type;
 	// Caution: here be dragons!
 	// Use C API to allow this code to be compiled with builds that don't have FW/MC/Rover
 
@@ -658,7 +657,7 @@ void RTL::get_rtl_xy_z_speed(uint8_t vehicle_type, float &xy, float &z)
 
 		case vehicle_status_s::VEHICLE_TYPE_FIXED_WING:
 			_rtl_xy_speed = param_find("FW_AIRSPD_TRIM");
-			_rtl_descent_speed = param_find("FW_T_SINK_MAX");
+			_rtl_descent_speed = param_find("FW_T_SINK_MIN");
 			break;
 
 		case vehicle_status_s::VEHICLE_TYPE_ROVER:

src/modules/navigator/rtl.h

@@ -94,6 +94,8 @@ public:
 
 	bool denyMissionLanding() { return _deny_mission_landing; }
 
+	void get_rtl_xy_z_speed(float &xy, float &z);
+	matrix::Vector2f get_wind();
 private:
 	/**
 	 * Set the RTL item
@@ -105,8 +107,6 @@ private:
 	 */
 	void advance_rtl();
 
-	void get_rtl_xy_z_speed(uint8_t vehicle_type, float &xy, float &z);
-	matrix::Vector2f get_wind();
 
 	float calculate_return_alt_from_cone_half_angle(float cone_half_angle_deg);