PX4-Autopilot/src/modules/ekf2/test/test_EKF_drag_fusion.cpp

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/**
 * Test the fusion of body frame specific forces for the estimation of wind speed
 */

#include <gtest/gtest.h>
#include "EKF/ekf.h"
#include "sensor_simulator/sensor_simulator.h"
#include "sensor_simulator/ekf_wrapper.h"
#include <lib/atmosphere/atmosphere.h>

class EkfDragFusionTest : public ::testing::Test
{
public:
	EkfDragFusionTest(): ::testing::Test(),
		_ekf{std::make_shared<Ekf>()},
		_sensor_simulator(_ekf),
		_ekf_wrapper(_ekf),
		_quat_sim(Eulerf(0.0f, 0.0f, 0.0f)) {};

	std::shared_ptr<Ekf> _ekf;
	SensorSimulator _sensor_simulator;
	EkfWrapper _ekf_wrapper;
	const Quatf _quat_sim;

	// Setup the Ekf with synthetic measurements
	void SetUp() override
	{
		// run briefly to init, then manually set in air and at rest (default for a real vehicle)
		_ekf->init(0);
		_ekf->set_is_fixed_wing(false);
		_ekf->set_in_air_status(false);
		_ekf->set_vehicle_at_rest(true);
	}

	// Use this method to clean up any memory, network etc. after each test
	void TearDown() override
	{
	}
};

TEST_F(EkfDragFusionTest, testForwardMomentumDrag)
{
	const float pitch = math::radians(10.0f);
	const float roll = math::radians(0.0f);
	const Eulerf euler_angles_sim(roll, pitch, 0.0f);
	const Quatf quat_sim(euler_angles_sim);
	_sensor_simulator.simulateOrientation(quat_sim);

	_ekf_wrapper.enableGpsFusion();
	_sensor_simulator.startGps();

	const float bcoef_x = 0.0f;
	const float bcoef_y = 0.0f;
	const float mcoef = 0.15f;
	_ekf_wrapper.setDragFusionParameters(bcoef_x, bcoef_y, mcoef);
	_ekf_wrapper.enableDragFusion();

	// simulate a vehicle that is hovering and tilting into wind

	_ekf->set_in_air_status(true);
	_ekf->set_vehicle_at_rest(false);

	// Wind estimation is slow when using drag fusion
	_sensor_simulator.runSeconds(90);

	EXPECT_TRUE(_ekf_wrapper.isWindVelocityEstimated());

	const Vector2f vel_wind_earth = _ekf->getWindVelocity();

	// drag acceleration = mcoef * airspeed
	Vector2f predicted_accel;
	predicted_accel(0) =   CONSTANTS_ONE_G * sinf(pitch);
	predicted_accel(1) = - CONSTANTS_ONE_G * sinf(roll);
	Vector2f wind_speed = predicted_accel / mcoef;
	EXPECT_NEAR(vel_wind_earth(0), wind_speed(0), fmaxf(1.0f, 0.1f * fabsf(wind_speed(0))));
	EXPECT_NEAR(vel_wind_earth(1), wind_speed(1), fmaxf(1.0f, 0.1f * fabsf(wind_speed(1))));
};

TEST_F(EkfDragFusionTest, testLateralMomentumDrag)
{
	const float pitch = math::radians(0.0f);
	const float roll = math::radians(10.0f);
	const Eulerf euler_angles_sim(roll, pitch, 0.0f);
	const Quatf quat_sim(euler_angles_sim);
	_sensor_simulator.simulateOrientation(quat_sim);

	_ekf_wrapper.enableGpsFusion();
	_sensor_simulator.startGps();

	// Apply parameter changes required to do drag fusion wind estimation
	const float bcoef_x = 0.0f;
	const float bcoef_y = 0.0f;
	const float mcoef = 0.15f;
	_ekf_wrapper.setDragFusionParameters(bcoef_x, bcoef_y, mcoef);
	_ekf_wrapper.enableDragFusion();

	// simulate a vehicle that is hovering and tilting into wind

	_ekf->set_in_air_status(true);
	_ekf->set_vehicle_at_rest(false);

	// Wind estimation is slow when using drag fusion
	_sensor_simulator.runSeconds(90);

	EXPECT_TRUE(_ekf_wrapper.isWindVelocityEstimated());

	const Vector2f vel_wind_earth = _ekf->getWindVelocity();

	// drag acceleration = mcoef * airspeed
	Vector2f predicted_accel;
	predicted_accel(0) =   CONSTANTS_ONE_G * sinf(pitch);
	predicted_accel(1) = - CONSTANTS_ONE_G * sinf(roll);
	Vector2f wind_speed = predicted_accel / mcoef;
	// Note that the wind direction is stightly incorrect heading estimate due to a mismatch between
	// the simulated mag field and assumed dectination from the WMM
	EXPECT_NEAR(vel_wind_earth(0), wind_speed(0), fmaxf(1.0f, 0.15f * fabsf(wind_speed.norm())));
	EXPECT_NEAR(vel_wind_earth(1), wind_speed(1), fmaxf(1.0f, 0.15f * fabsf(wind_speed.norm())));
};

TEST_F(EkfDragFusionTest, testForwardBluffBodyDrag)
{
	const float roll = math::radians(0.0f);
	const float pitch = math::radians(-10.0f);
	const Eulerf euler_angles_sim(roll, pitch, 0.0f);
	const Quatf quat_sim(euler_angles_sim);
	_sensor_simulator.simulateOrientation(quat_sim);

	_ekf_wrapper.enableGpsFusion();
	_sensor_simulator.startGps();

	// Apply parameter changes required to do drag fusion wind estimation
	const float bcoef_x = 70.0f;
	const float bcoef_y = 50.0f;
	const float mcoef = 0.0f;
	_ekf_wrapper.setDragFusionParameters(bcoef_x, bcoef_y, mcoef);
	_ekf_wrapper.enableDragFusion();

	// simulate a vehicle that is hovering and tilting into wind

	_ekf->set_in_air_status(true);
	_ekf->set_vehicle_at_rest(false);

	// Wind estimation is slow when using drag fusion
	_sensor_simulator.runSeconds(90);

	EXPECT_TRUE(_ekf_wrapper.isWindVelocityEstimated());

	const Vector2f vel_wind_earth = _ekf->getWindVelocity();

	Vector2f predicted_accel(CONSTANTS_ONE_G * sinf(pitch), 0.0f);
	const float airspeed = sqrtf((2.0f * bcoef_x * predicted_accel.length()) /
				     atmosphere::kAirDensitySeaLevelStandardAtmos);
	Vector2f wind_speed(-airspeed, 0.0f);

	// The magnitude of error perpendicular to wind is equivalent to the error in the direction of wind
	// which is why we use the same threshold for each axis.
	EXPECT_NEAR(vel_wind_earth(0), wind_speed(0), 1.0f);
	EXPECT_NEAR(vel_wind_earth(1), wind_speed(1), 1.0f);
};

TEST_F(EkfDragFusionTest, testLateralBluffBodyDrag)
{
	const float roll = math::radians(10.0f);
	const float pitch = math::radians(0.0f);
	const Eulerf euler_angles_sim(roll, pitch, 0.0f);
	const Quatf quat_sim(euler_angles_sim);
	_sensor_simulator.simulateOrientation(quat_sim);

	_ekf_wrapper.enableGpsFusion();
	_sensor_simulator.startGps();

	// Apply parameter changes required to do drag fusion wind estimation
	const float bcoef_x = 70.0f;
	const float bcoef_y = 50.0f;
	const float mcoef = 0.0f;
	_ekf_wrapper.setDragFusionParameters(bcoef_x, bcoef_y, mcoef);
	_ekf_wrapper.enableDragFusion();

	// simulate a vehicle that is hovering and tilting into wind
	_ekf->set_in_air_status(true);
	_ekf->set_vehicle_at_rest(false);

	// Wind estimation is slow when using drag fusion
	_sensor_simulator.runSeconds(90);

	EXPECT_TRUE(_ekf_wrapper.isWindVelocityEstimated());

	const Vector2f vel_wind_earth = _ekf->getWindVelocity();

	Vector2f predicted_accel(0.0f, - CONSTANTS_ONE_G * sinf(roll));
	const float airspeed = sqrtf((2.0f * bcoef_y * predicted_accel.length()) /
				     atmosphere::kAirDensitySeaLevelStandardAtmos);
	Vector2f wind_speed(0.0f, -airspeed);

	// The magnitude of error perpendicular to wind is equivalent to the error in the of wind
	// which is why we use the same threshold for each axis.
	EXPECT_NEAR(vel_wind_earth(0), wind_speed(0), 1.0f);
	EXPECT_NEAR(vel_wind_earth(1), wind_speed(1), 1.0f);
};

TEST_F(EkfDragFusionTest, testDiagonalBluffBodyDrag)
{
	const float roll = math::radians(-10.0f);
	const float pitch = math::radians(-10.0f);
	const Eulerf euler_angles_sim(roll, pitch, 0.f);
	const Quatf quat_sim(euler_angles_sim);
	_sensor_simulator.simulateOrientation(quat_sim);

	_ekf_wrapper.enableGpsFusion();
	_sensor_simulator.startGps();

	// Apply parameter changes required to do drag fusion wind estimation
	const float bcoef_x = 50.0f;
	const float bcoef_y = 50.0f;
	const float mcoef = 0.0f;
	_ekf_wrapper.setDragFusionParameters(bcoef_x, bcoef_y, mcoef);
	_ekf_wrapper.enableDragFusion();

	// simulate a vehicle that is hovering and tilting into wind
	_ekf->set_in_air_status(true);
	_ekf->set_vehicle_at_rest(false);

	// Wind estimation is slow when using drag fusion
	_sensor_simulator.runSeconds(90);

	EXPECT_TRUE(_ekf_wrapper.isWindVelocityEstimated());

	const Vector2f vel_wind_earth = _ekf->getWindVelocity();

	Vector2f predicted_accel = quat_sim.rotateVectorInverse(Vector3f(0.f, 0.f, -CONSTANTS_ONE_G)).xy();
	const float airspeed = sqrtf((2.0f * bcoef_y * predicted_accel.norm()) /
				     atmosphere::kAirDensitySeaLevelStandardAtmos);
	Vector2f wind_speed(airspeed * predicted_accel / predicted_accel.norm());

	// The magnitude of error perpendicular to wind is equivalent to the error in the of wind
	// which is why we use the same threshold for each axis.
	EXPECT_NEAR(vel_wind_earth(0), wind_speed(0), 1.0f);
	EXPECT_NEAR(vel_wind_earth(1), wind_speed(1), 1.0f);
};