void Ekf::controlGpsAiding()
{
// GPS fusion mode selection logic
// To start use GPS we need angular alignment completed, the local NED origin set and fresh GPS data
if ((_params.fusion_mode & MASK_USE_GPS) && !_control_status.flags.gps) {
if (_control_status.flags.tilt_align && (_time_last_imu - _time_last_gps) < 5e5 && _NED_origin_initialised
&& (_time_last_imu - _last_gps_fail_us > 5e6)) {
// If the heading is not aligned, reset the yaw and magnetic field states
if (!_control_status.flags.yaw_align) {
_control_status.flags.yaw_align = resetMagHeading(_mag_sample_delayed.mag);
}
// If the heading is valid start using gps aiding
if (_control_status.flags.yaw_align) {
_control_status.flags.gps = true;
_time_last_gps = _time_last_imu;
// if we are not already aiding with optical flow, then we need to reset the position and velocity
if (!_control_status.flags.opt_flow) {
_control_status.flags.gps = resetPosition();
_control_status.flags.gps = resetVelocity();
}
}
}
} else if (!(_params.fusion_mode & MASK_USE_GPS)) {
_control_status.flags.gps = false;
}
// handle the case when we are relying on GPS fusion and lose it
if (_control_status.flags.gps && !_control_status.flags.opt_flow) {
// We are relying on GPS aiding to constrain attitude drift so after 10 seconds without aiding we need to do something
if ((_time_last_imu - _time_last_pos_fuse > 10e6) && (_time_last_imu - _time_last_vel_fuse > 10e6)) {
if (_time_last_imu - _time_last_gps > 5e5) {
// if we don't have gps then we need to switch to the non-aiding mode, zero the velocity states
// and set the synthetic GPS position to the current estimate
_control_status.flags.gps = false;
_last_known_posNE(0) = _state.pos(0);
_last_known_posNE(1) = _state.pos(1);
_state.vel.setZero();
} else {
// Reset states to the last GPS measurement
resetPosition();
resetVelocity();
// Reset the timeout counters
_time_last_pos_fuse = _time_last_imu;
_time_last_vel_fuse = _time_last_imu;
}
}
}
}
void Projectile::moveProjectile(sf::Time dt)
{
sf::Vector2f pos = getPosition();
if (bHasTarget) {
if (!reachedTarget) {
fDistance = sqrt(pow(targetPos.x - pos.x,2) + pow(targetPos.y - pos.y,2));
//Calculate new velocity
velocity.x = getSpeed() * (targetPos.x - pos.x) / fDistance;
velocity.y = getSpeed() * (targetPos.y - pos.y) / fDistance;
if (fDistance > -1 && fDistance < 1)
{
reachedTarget = true;
resetVelocity();
}
}
}
//Rotate to face the target
float dx = targetPos.x - pos.x;
float dy = targetPos.y - pos.y;
const float Pi = 3.141;
setRotation(atan2(dy,dx) * (180 / Pi) + 90); //Calculates rotation
move(getVelocity() * dt.asSeconds());
}
void Ball::resetPosition() {
bounds.left = 385;
bounds.top = 285;
changeXDirection();
m_rect.setPosition(bounds.left, bounds.top);
resetMoveCountdown();
resetVelocity();
}
/**
* @brief Process individual keyboard inputs.
*
* @param c keyboard input.
*/
void KeyOpCore::processKeyboardInput(char c)
{
/*
* Arrow keys are a bit special, they are escape characters - meaning they
* trigger a sequence of keycodes. In this case, 'esc-[-Keycode_xxx'. We
* ignore the esc-[ and just parse the last one. So long as we avoid using
* the last one for its actual purpose (e.g. left arrow corresponds to
* esc-[-D) we can keep the parsing simple.
*/
switch (c)
{
case kobuki_msgs::KeyboardInput::KeyCode_Left:
{
incrementAngularVelocity();
break;
}
case kobuki_msgs::KeyboardInput::KeyCode_Right:
{
decrementAngularVelocity();
break;
}
case kobuki_msgs::KeyboardInput::KeyCode_Up:
{
incrementLinearVelocity();
break;
}
case kobuki_msgs::KeyboardInput::KeyCode_Down:
{
decrementLinearVelocity();
break;
}
case kobuki_msgs::KeyboardInput::KeyCode_Space:
{
resetVelocity();
break;
}
case 'q':
{
quit_requested = true;
break;
}
case 'd':
{
disable();
break;
}
case 'e':
{
enable();
break;
}
default:
{
break;
}
}
}
/**
* @brief Process individual keyboard inputs.
*
* @param c keyboard input.
*/
void KeyOp::processKeyboardInput(char c)
{
/*
* Arrow keys are a bit special, they are escape characters - meaning they
* trigger a sequence of keycodes. In this case, 'esc-[-Keycode_xxx'. We
* ignore the esc-[ and just parse the last one. So long as we avoid using
* the last one for its actual purpose (e.g. left arrow corresponds to
* esc-[-D) we can keep the parsing simple.
*/
switch (c)
{
case KEYCODE_LEFT:
{
incrementAngularVelocity();
break;
}
case KEYCODE_RIGHT:
{
decrementAngularVelocity();
break;
}
case KEYCODE_UP:
{
incrementLinearVelocity();
break;
}
case KEYCODE_DOWN:
{
decrementLinearVelocity();
break;
}
case KEYCODE_SPACE:
{
resetVelocity();
break;
}
case 'q':
{
quit_requested_ = true;
break;
}
case 'd':
{
disable();
break;
}
case 'e':
{
enable();
break;
}
default:
{
break;
}
}
}
//figures out what needs to happen at an intersection based on the direction we want to turn
void Robot::handleIntersection(Direction direction){
switch (direction) {
case StraightAhead:
break;
case Left:
Tape::resetErrors();
resetVelocity();
turnAtIntersection(false, millis());
break;
case Right:
Tape::resetErrors();
resetVelocity();
turnAtIntersection(true, millis());
break;
case TurnAround:
Tape::resetErrors();
resetVelocity();
turnOntoTape(direction);
break;
case SlightRight:
Actuators::drive(velocity(), SLIGHT_RIGHT_AT_SPECIAL_INTERSECTION_TURN);
delay(SLIGHT_RIGHT_AT_SPECIAL_INTERSECTION_DURATION);
Tape::resetErrors();
resetVelocity();
findTape();
break;
case SlightLeft:
Actuators::drive(VELOCITY_SLOW, -SLIGHT_LEFT_AT_SPECIAL_INTERSECTION_TURN);
delay(SLIGHT_LEFT_AT_SPECIAL_INTERSECTION_DURATION);
Tape::resetErrors();
resetVelocity();
findTape();
break;
}
}
void SahWorldInterface::create(CudaDynamicWorld * world)
{
#if COLLIDEJUST
return DynamicWorldInterface::create(world);
#endif
world->setBvhBuilder(new SahBuilder);
SahTetrahedronSystem * tetra = new SahTetrahedronSystem;
if(!readMeshFromFile(tetra)) createTestMesh(tetra);
resetVelocity(tetra);
tetra->setTotalMass(4000.f);
world->addTetrahedronSystem(tetra);
}
void Robot::turnOntoTape(bool turnRight) {
resetVelocity();
Actuators::turnInPlace(turnRight);
delay(TURN_OFF_TAPE_DURATION);
while (Tape::tapePresentCentreWithUpdate()) {}
delay(10);
unsigned long timeStamp = millis();
while (!Tape::tapePresentCentreWithUpdate()) {
if (millis() - timeStamp > GETTING_UNSTUCK_STARTING_TIME) {
Actuators::drive(VELOCITY_SLOW, Actuators::Straight);
delay(GETTING_UNSTUCK_DELAY);
timeStamp = millis();
Actuators::turnInPlace(turnRight);
}
}
}
void Robot::turnOntoTape(Direction direction) {
switch (direction) {
case StraightAhead:
break;
case Left:
turnOntoTape(false);
break;
case Right:
turnOntoTape(true);
break;
case TurnAround:
resetVelocity();
Actuators::turnInPlace(TURN_180_DURATOIN, true);
while (!Tape::tapePresentCentreWithUpdate()) {}
break;
}
}
bool Ekf::initialiseFilter(void)
{
_state.ang_error.setZero();
_state.vel.setZero();
_state.pos.setZero();
_state.gyro_bias.setZero();
_state.gyro_scale(0) = _state.gyro_scale(1) = _state.gyro_scale(2) = 1.0f;
_state.accel_z_bias = 0.0f;
_state.mag_I.setZero();
_state.mag_B.setZero();
_state.wind_vel.setZero();
// get initial roll and pitch estimate from accel vector, assuming vehicle is static
Vector3f accel_init = _imu_down_sampled.delta_vel / _imu_down_sampled.delta_vel_dt;
float pitch = 0.0f;
float roll = 0.0f;
if (accel_init.norm() > 0.001f) {
accel_init.normalize();
pitch = asinf(accel_init(0));
roll = -asinf(accel_init(1) / cosf(pitch));
}
matrix::Euler<float> euler_init(roll, pitch, 0.0f);
// Get the latest magnetic field measurement.
// If we don't have a measurement then we cannot initialise the filter
magSample mag_init = _mag_buffer.get_newest();
if (mag_init.time_us == 0) {
return false;
}
// rotate magnetic field into earth frame assuming zero yaw and estimate yaw angle assuming zero declination
// TODO use declination if available
matrix::Dcm<float> R_to_earth_zeroyaw(euler_init);
Vector3f mag_ef_zeroyaw = R_to_earth_zeroyaw * mag_init.mag;
float declination = 0.0f;
euler_init(2) = declination - atan2f(mag_ef_zeroyaw(1), mag_ef_zeroyaw(0));
// calculate initial quaternion states
_state.quat_nominal = Quaternion(euler_init);
_output_new.quat_nominal = _state.quat_nominal;
// calculate initial earth magnetic field states
matrix::Dcm<float> R_to_earth(euler_init);
_state.mag_I = R_to_earth * mag_init.mag;
resetVelocity();
resetPosition();
// initialize vertical position with newest baro measurement
baroSample baro_init = _baro_buffer.get_newest();
if (baro_init.time_us == 0) {
return false;
}
_state.pos(2) = -baro_init.hgt;
_output_new.pos(2) = -baro_init.hgt;
initialiseCovariance();
return true;
}
void Ekf::controlExternalVisionFusion()
{
// Check for new exernal vision data
if (_ev_data_ready) {
// external vision position aiding selection logic
if ((_params.fusion_mode & MASK_USE_EVPOS) && !_control_status.flags.ev_pos && _control_status.flags.tilt_align && _control_status.flags.yaw_align) {
// check for a exernal vision measurement that has fallen behind the fusion time horizon
if (_time_last_imu - _time_last_ext_vision < 2 * EV_MAX_INTERVAL) {
// turn on use of external vision measurements for position and height
_control_status.flags.ev_pos = true;
ECL_INFO("EKF switching to external vision position fusion");
// turn off other forms of height aiding
_control_status.flags.baro_hgt = false;
_control_status.flags.gps_hgt = false;
_control_status.flags.rng_hgt = false;
// reset the position, height and velocity
resetPosition();
resetVelocity();
resetHeight();
}
}
// external vision yaw aiding selection logic
if ((_params.fusion_mode & MASK_USE_EVYAW) && !_control_status.flags.ev_yaw && _control_status.flags.tilt_align) {
// check for a exernal vision measurement that has fallen behind the fusion time horizon
if (_time_last_imu - _time_last_ext_vision < 2 * EV_MAX_INTERVAL) {
// reset the yaw angle to the value from the observaton quaternion
// get the roll, pitch, yaw estimates from the quaternion states
matrix::Quaternion<float> q_init(_state.quat_nominal(0), _state.quat_nominal(1), _state.quat_nominal(2),
_state.quat_nominal(3));
matrix::Euler<float> euler_init(q_init);
// get initial yaw from the observation quaternion
extVisionSample ev_newest = _ext_vision_buffer.get_newest();
matrix::Quaternion<float> q_obs(ev_newest.quat(0), ev_newest.quat(1), ev_newest.quat(2), ev_newest.quat(3));
matrix::Euler<float> euler_obs(q_obs);
euler_init(2) = euler_obs(2);
// save a copy of the quaternion state for later use in calculating the amount of reset change
Quaternion quat_before_reset = _state.quat_nominal;
// calculate initial quaternion states for the ekf
_state.quat_nominal = Quaternion(euler_init);
// calculate the amount that the quaternion has changed by
_state_reset_status.quat_change = _state.quat_nominal * quat_before_reset.inversed();
// add the reset amount to the output observer buffered data
outputSample output_states;
unsigned output_length = _output_buffer.get_length();
for (unsigned i=0; i < output_length; i++) {
output_states = _output_buffer.get_from_index(i);
output_states.quat_nominal *= _state_reset_status.quat_change;
_output_buffer.push_to_index(i,output_states);
}
// capture the reset event
_state_reset_status.quat_counter++;
// flag the yaw as aligned
_control_status.flags.yaw_align = true;
// turn on fusion of external vision yaw measurements and disable all magnetoemter fusion
_control_status.flags.ev_yaw = true;
_control_status.flags.mag_hdg = false;
_control_status.flags.mag_3D = false;
_control_status.flags.mag_dec = false;
ECL_INFO("EKF switching to external vision yaw fusion");
}
}
// determine if we should use the height observation
if (_params.vdist_sensor_type == VDIST_SENSOR_EV) {
_control_status.flags.baro_hgt = false;
_control_status.flags.gps_hgt = false;
_control_status.flags.rng_hgt = false;
_control_status.flags.ev_hgt = true;
_fuse_height = true;
}
// determine if we should use the horizontal position observations
if (_control_status.flags.ev_pos) {
_fuse_pos = true;
// correct position and height for offset relative to IMU
Vector3f pos_offset_body = _params.ev_pos_body - _params.imu_pos_body;
Vector3f pos_offset_earth = _R_to_earth * pos_offset_body;
_ev_sample_delayed.posNED(0) -= pos_offset_earth(0);
_ev_sample_delayed.posNED(1) -= pos_offset_earth(1);
_ev_sample_delayed.posNED(2) -= pos_offset_earth(2);
}
// determine if we should use the yaw observation
if (_control_status.flags.ev_yaw) {
fuseHeading();
}
}
}
void Ekf::controlGpsFusion()
{
// Check for new GPS data that has fallen behind the fusion time horizon
if (_gps_data_ready) {
// Determine if we should use GPS aiding for velocity and horizontal position
// To start using GPS we need angular alignment completed, the local NED origin set and GPS data that has not failed checks recently
if ((_params.fusion_mode & MASK_USE_GPS) && !_control_status.flags.gps) {
if (_control_status.flags.tilt_align && _NED_origin_initialised && (_time_last_imu - _last_gps_fail_us > 5e6)) {
// If the heading is not aligned, reset the yaw and magnetic field states
if (!_control_status.flags.yaw_align) {
_control_status.flags.yaw_align = resetMagHeading(_mag_sample_delayed.mag);
}
// If the heading is valid start using gps aiding
if (_control_status.flags.yaw_align) {
_control_status.flags.gps = true;
_time_last_gps = _time_last_imu;
// if we are not already aiding with optical flow, then we need to reset the position and velocity
if (!_control_status.flags.opt_flow) {
if (resetPosition() && resetVelocity()) {
_control_status.flags.gps = true;
} else {
_control_status.flags.gps = false;
}
}
if (_control_status.flags.gps) {
ECL_INFO("EKF commencing GPS aiding");
}
}
}
} else if (!(_params.fusion_mode & MASK_USE_GPS)) {
_control_status.flags.gps = false;
}
// handle the case when we are relying on GPS fusion and lose it
if (_control_status.flags.gps && !_control_status.flags.opt_flow) {
// We are relying on GPS aiding to constrain attitude drift so after 10 seconds without aiding we need to do something
if ((_time_last_imu - _time_last_pos_fuse > 10e6) && (_time_last_imu - _time_last_vel_fuse > 10e6)) {
if (_time_last_imu - _time_last_gps > 5e5) {
// if we don't have gps then we need to switch to the non-aiding mode, zero the velocity states
// and set the synthetic GPS position to the current estimate
_control_status.flags.gps = false;
_last_known_posNE(0) = _state.pos(0);
_last_known_posNE(1) = _state.pos(1);
_state.vel.setZero();
ECL_WARN("EKF GPS fusion timout - stopping GPS aiding");
} else {
// Reset states to the last GPS measurement
resetPosition();
resetVelocity();
ECL_WARN("EKF GPS fusion timout - resetting to GPS");
// Reset the timeout counters
_time_last_pos_fuse = _time_last_imu;
_time_last_vel_fuse = _time_last_imu;
}
}
}
// Only use GPS data for position and velocity aiding if enabled
if (_control_status.flags.gps) {
_fuse_pos = true;
_fuse_vert_vel = true;
_fuse_hor_vel = true;
// correct velocity for offset relative to IMU
Vector3f ang_rate = _imu_sample_delayed.delta_ang * (1.0f/_imu_sample_delayed.delta_ang_dt);
Vector3f pos_offset_body = _params.gps_pos_body - _params.imu_pos_body;
Vector3f vel_offset_body = cross_product(ang_rate,pos_offset_body);
Vector3f vel_offset_earth = _R_to_earth * vel_offset_body;
_gps_sample_delayed.vel -= vel_offset_earth;
// correct position and height for offset relative to IMU
Vector3f pos_offset_earth = _R_to_earth * pos_offset_body;
_gps_sample_delayed.pos(0) -= pos_offset_earth(0);
_gps_sample_delayed.pos(1) -= pos_offset_earth(1);
_gps_sample_delayed.hgt += pos_offset_earth(2);
}
// Determine if GPS should be used as the height source
if (((_params.vdist_sensor_type == VDIST_SENSOR_GPS)) && !_gps_hgt_faulty) {
_control_status.flags.baro_hgt = false;
_control_status.flags.gps_hgt = true;
_control_status.flags.rng_hgt = false;
_control_status.flags.ev_hgt = false;
_fuse_height = true;
}
}
}
void Ekf::controlExternalVisionAiding()
{
// external vision position aiding selection logic
if ((_params.fusion_mode & MASK_USE_EVPOS) && !_control_status.flags.ev_pos && _control_status.flags.tilt_align && _control_status.flags.yaw_align) {
// check for a exernal vision measurement that has fallen behind the fusion time horizon
if (_time_last_imu - _time_last_ext_vision < 2 * EV_MAX_INTERVAL) {
// turn on use of external vision measurements for position and height
_control_status.flags.ev_pos = true;
printf("EKF switching to external vision position fusion\n");
// turn off other forms of height aiding
_control_status.flags.baro_hgt = false;
_control_status.flags.gps_hgt = false;
_control_status.flags.rng_hgt = false;
// reset the position, height and velocity
resetPosition();
resetVelocity();
resetHeight();
}
}
// external vision yaw aiding selection logic
if ((_params.fusion_mode & MASK_USE_EVYAW) && !_control_status.flags.ev_yaw && _control_status.flags.tilt_align) {
// check for a exernal vision measurement that has fallen behind the fusion time horizon
if (_time_last_imu - _time_last_ext_vision < 2 * EV_MAX_INTERVAL) {
// reset the yaw angle to the value from the observaton quaternion
// get the roll, pitch, yaw estimates from the quaternion states
matrix::Quaternion<float> q_init(_state.quat_nominal(0), _state.quat_nominal(1), _state.quat_nominal(2),
_state.quat_nominal(3));
matrix::Euler<float> euler_init(q_init);
// get initial yaw from the observation quaternion
extVisionSample ev_newest = _ext_vision_buffer.get_newest();
matrix::Quaternion<float> q_obs(ev_newest.quat(0), ev_newest.quat(1), ev_newest.quat(2), ev_newest.quat(3));
matrix::Euler<float> euler_obs(q_obs);
euler_init(2) = euler_obs(2);
// save a copy of the quaternion state for later use in calculating the amount of reset change
Quaternion quat_before_reset = _state.quat_nominal;
// calculate initial quaternion states for the ekf
_state.quat_nominal = Quaternion(euler_init);
// calculate the amount that the quaternion has changed by
_state_reset_status.quat_change = _state.quat_nominal * quat_before_reset.inversed();
// add the reset amount to the output observer buffered data
outputSample output_states;
unsigned output_length = _output_buffer.get_length();
for (unsigned i=0; i < output_length; i++) {
output_states = _output_buffer.get_from_index(i);
output_states.quat_nominal *= _state_reset_status.quat_change;
_output_buffer.push_to_index(i,output_states);
}
// capture the reset event
_state_reset_status.quat_counter++;
// flag the yaw as aligned
_control_status.flags.yaw_align = true;
// turn on fusion of external vision yaw measurements and disable all magnetoemter fusion
_control_status.flags.ev_yaw = true;
_control_status.flags.mag_hdg = false;
_control_status.flags.mag_3D = false;
_control_status.flags.mag_dec = false;
printf("EKF switching to external vision yaw fusion\n");
}
}
}
//Main function of the robot. Drives, detects IR, and detects collisions.
//Most importantly, gives status updates to the controller so the controller
//can decide what to do.
Status Robot::cruise(Direction direction) {
handleIntersection(direction);
while (true) {
//tape follows always
Tape::update();
followTape();
//we must be at an intersection, tell this to the controller
if (Tape::atIntersection() && (millis() - lastIntersectionTime) > TIME_MIN_BETWEEN_INTERSECTIONS) {
lastIntersectionTime = millis();
Actuators::stop();
return Intersection;
}
Collision::update();
//tell the controller we collided
if (Collision::occured()) {
resetVelocity();
return Collided;
}
IR::update();
//tell the controller the status of IR signals
switch (IR::check()) {
case IR::None:
setVelocity(VELOCITY_NORMAL);
break;
case IR::WeakLeft:
if(!hasPassenger){
setVelocity(VELOCITY_SLOW);
}
break;
case IR::WeakRight:
if(!hasPassenger){
setVelocity(VELOCITY_SLOW);
}
break;
case IR::StrongLeft:
if(!hasPassenger){
Actuators::stop();
resetVelocity();
IR::resetIR();
return IRLeft;
}
break;
case IR::StrongRight:
if(!hasPassenger){
Actuators::stop();
resetVelocity();
IR::resetIR();
return IRRight;
}
break;
}
}
}
void Ekf::controlFusionModes()
{
// Determine the vehicle status
calculateVehicleStatus();
// Get the magnetic declination
calcMagDeclination();
// Check for tilt convergence during initial alignment
// filter the tilt error vector using a 1 sec time constant LPF
float filt_coef = 1.0f * _imu_sample_delayed.delta_ang_dt;
_tilt_err_length_filt = filt_coef * _tilt_err_vec.norm() + (1.0f - filt_coef) * _tilt_err_length_filt;
// Once the tilt error has reduced sufficiently, initialise the yaw and magnetic field states
if (_tilt_err_length_filt < 0.005f && !_control_status.flags.tilt_align) {
_control_status.flags.tilt_align = true;
_control_status.flags.yaw_align = resetMagHeading(_mag_sample_delayed.mag);
}
// optical flow fusion mode selection logic
// to start using optical flow data we need angular alignment complete, and fresh optical flow and height above terrain data
if ((_params.fusion_mode & MASK_USE_OF) && !_control_status.flags.opt_flow && _control_status.flags.tilt_align
&& (_time_last_imu - _time_last_optflow) < 5e5 && (_time_last_imu - _time_last_hagl_fuse) < 5e5) {
// If the heading is not aligned, reset the yaw and magnetic field states
if (!_control_status.flags.yaw_align) {
_control_status.flags.yaw_align = resetMagHeading(_mag_sample_delayed.mag);
}
// If the heading is valid, start using optical flow aiding
if (_control_status.flags.yaw_align) {
// set the flag and reset the fusion timeout
_control_status.flags.opt_flow = true;
_time_last_of_fuse = _time_last_imu;
// if we are not using GPS and are in air, then we need to reset the velocity to be consistent with the optical flow reading
if (!_control_status.flags.gps) {
// calculate the rotation matrix from body to earth frame
matrix::Dcm<float> body_to_earth(_state.quat_nominal);
// constrain height above ground to be above minimum possible
float heightAboveGndEst = fmaxf((_terrain_vpos - _state.pos(2)), _params.rng_gnd_clearance);
// calculate absolute distance from focal point to centre of frame assuming a flat earth
float range = heightAboveGndEst / body_to_earth(2, 2);
if (_in_air && (range - _params.rng_gnd_clearance) > 0.3f && _flow_sample_delayed.dt > 0.05f) {
// calculate X and Y body relative velocities from OF measurements
Vector3f vel_optflow_body;
vel_optflow_body(0) = - range * _flow_sample_delayed.flowRadXYcomp(1) / _flow_sample_delayed.dt;
vel_optflow_body(1) = range * _flow_sample_delayed.flowRadXYcomp(0) / _flow_sample_delayed.dt;
vel_optflow_body(2) = 0.0f;
// rotate from body to earth frame
Vector3f vel_optflow_earth;
vel_optflow_earth = body_to_earth * vel_optflow_body;
// take x and Y components
_state.vel(0) = vel_optflow_earth(0);
_state.vel(1) = vel_optflow_earth(1);
} else {
_state.vel.setZero();
}
}
}
} else if (!(_params.fusion_mode & MASK_USE_OF)) {
_control_status.flags.opt_flow = false;
}
// GPS fusion mode selection logic
// To start use GPS we need angular alignment completed, the local NED origin set and fresh GPS data
if ((_params.fusion_mode & MASK_USE_GPS) && !_control_status.flags.gps) {
if (_control_status.flags.tilt_align && (_time_last_imu - _time_last_gps) < 5e5 && _NED_origin_initialised
&& (_time_last_imu - _last_gps_fail_us > 5e6)) {
// If the heading is not aligned, reset the yaw and magnetic field states
if (!_control_status.flags.yaw_align) {
_control_status.flags.yaw_align = resetMagHeading(_mag_sample_delayed.mag);
}
// If the heading is valid start using gps aiding
if (_control_status.flags.yaw_align) {
_control_status.flags.gps = true;
_time_last_gps = _time_last_imu;
// if we are not already aiding with optical flow, then we need to reset the position and velocity
if (!_control_status.flags.opt_flow) {
_control_status.flags.gps = resetPosition();
_control_status.flags.gps = resetVelocity();
}
}
}
} else if (!(_params.fusion_mode & MASK_USE_GPS)) {
_control_status.flags.gps = false;
}
// handle the case when we are relying on GPS fusion and lose it
if (_control_status.flags.gps && !_control_status.flags.opt_flow) {
// We are relying on GPS aiding to constrain attitude drift so after 10 seconds without aiding we need to do something
if ((_time_last_imu - _time_last_pos_fuse > 10e6) && (_time_last_imu - _time_last_vel_fuse > 10e6)) {
if (_time_last_imu - _time_last_gps > 5e5) {
// if we don't have gps then we need to switch to the non-aiding mode, zero the veloity states
// and set the synthetic GPS position to the current estimate
_control_status.flags.gps = false;
_last_known_posNE(0) = _state.pos(0);
_last_known_posNE(1) = _state.pos(1);
_state.vel.setZero();
} else {
// Reset states to the last GPS measurement
resetPosition();
resetVelocity();
}
}
}
/*
* Handle the case where we have not fused height measurements recently and
* uncertainty exceeds the max allowable. Reset using the best available height
* measurement source, continue using it after the reset and declare the current
* source failed if we have switched.
*/
if ((P[8][8] > sq(_params.hgt_reset_lim)) && ((_time_last_imu - _time_last_hgt_fuse) > 5e6)) {
// handle the case where we are using baro for height
if (_control_status.flags.baro_hgt) {
// check if GPS height is available
gpsSample gps_init = _gps_buffer.get_newest();
bool gps_hgt_available = ((_time_last_imu - gps_init.time_us) < 2 * GPS_MAX_INTERVAL);
bool gps_hgt_accurate = (gps_init.vacc < _params.req_vacc);
baroSample baro_init = _baro_buffer.get_newest();
bool baro_hgt_available = ((_time_last_imu - baro_init.time_us) < 2 * BARO_MAX_INTERVAL);
// use the gps if it is accurate or there is no baro data available
if (gps_hgt_available && (gps_hgt_accurate || !baro_hgt_available)) {
// declare the baro as unhealthy
_baro_hgt_faulty = true;
// set the height mode to the GPS
_control_status.flags.baro_hgt = false;
_control_status.flags.gps_hgt = true;
_control_status.flags.rng_hgt = false;
// adjust the height offset so we can use the GPS
_hgt_sensor_offset = _state.pos(2) + gps_init.hgt - _gps_alt_ref;
if (!baro_hgt_available) {
printf("EKF baro hgt timeout - switching to gps\n");
}
}
}
// handle the case we are using GPS for height
if (_control_status.flags.gps_hgt) {
// check if GPS height is available
gpsSample gps_init = _gps_buffer.get_newest();
bool gps_hgt_available = ((_time_last_imu - gps_init.time_us) < 2 * GPS_MAX_INTERVAL);
bool gps_hgt_accurate = (gps_init.vacc < _params.req_vacc);
// check the baro height source for consistency and freshness
baroSample baro_init = _baro_buffer.get_newest();
bool baro_data_fresh = ((_time_last_imu - baro_init.time_us) < 2 * BARO_MAX_INTERVAL);
float baro_innov = _state.pos(2) - (_hgt_sensor_offset - baro_init.hgt + _baro_hgt_offset);
bool baro_data_consistent = fabsf(baro_innov) < (sq(_params.baro_noise) + P[8][8]) * sq(_params.baro_innov_gate);
// if baro data is consistent and fresh or GPS height is unavailable or inaccurate, we switch to baro for height
if ((baro_data_consistent && baro_data_fresh) || !gps_hgt_available || !gps_hgt_accurate) {
// declare the GPS height unhealthy
_gps_hgt_faulty = true;
// set the height mode to the baro
_control_status.flags.baro_hgt = true;
_control_status.flags.gps_hgt = false;
_control_status.flags.rng_hgt = false;
printf("EKF gps hgt timeout - switching to baro\n");
}
}
// handle the case we are using range finder for height
if (_control_status.flags.rng_hgt) {
// check if range finder data is available
rangeSample rng_init = _range_buffer.get_newest();
bool rng_data_available = ((_time_last_imu - rng_init.time_us) < 2 * RNG_MAX_INTERVAL);
// check if baro data is available
baroSample baro_init = _baro_buffer.get_newest();
bool baro_data_available = ((_time_last_imu - baro_init.time_us) < 2 * BARO_MAX_INTERVAL);
// check if baro data is consistent
float baro_innov = _state.pos(2) - (_hgt_sensor_offset - baro_init.hgt + _baro_hgt_offset);
bool baro_data_consistent = sq(baro_innov) < (sq(_params.baro_noise) + P[8][8]) * sq(_params.baro_innov_gate);
// switch to baro if necessary or preferable
bool switch_to_baro = (!rng_data_available && baro_data_available) || (baro_data_consistent && baro_data_available);
if (switch_to_baro) {
// declare the range finder height unhealthy
_rng_hgt_faulty = true;
// set the height mode to the baro
_control_status.flags.baro_hgt = true;
_control_status.flags.gps_hgt = false;
_control_status.flags.rng_hgt = false;
printf("EKF rng hgt timeout - switching to baro\n");
}
}
// Reset vertical position and velocity states to the last measurement
resetHeight();
}
// handle the case when we are relying on optical flow fusion and lose it
if (_control_status.flags.opt_flow && !_control_status.flags.gps) {
// We are relying on flow aiding to constrain attitude drift so after 5s without aiding we need to do something
if ((_time_last_imu - _time_last_of_fuse > 5e6)) {
// Switch to the non-aiding mode, zero the veloity states
// and set the synthetic position to the current estimate
_control_status.flags.opt_flow = false;
_last_known_posNE(0) = _state.pos(0);
_last_known_posNE(1) = _state.pos(1);
_state.vel.setZero();
}
}
// Determine if we should use simple magnetic heading fusion which works better when there are large external disturbances
// or the more accurate 3-axis fusion
if (_params.mag_fusion_type == MAG_FUSE_TYPE_AUTO) {
if (!_control_status.flags.armed) {
// use heading fusion for initial startup
_control_status.flags.mag_hdg = true;
_control_status.flags.mag_2D = false;
_control_status.flags.mag_3D = false;
} else {
if (_control_status.flags.in_air) {
// if transitioning into 3-axis fusion mode, we need to initialise the yaw angle and field states
if (!_control_status.flags.mag_3D) {
_control_status.flags.yaw_align = resetMagHeading(_mag_sample_delayed.mag);
}
// use 3D mag fusion when airborne
_control_status.flags.mag_hdg = false;
_control_status.flags.mag_2D = false;
_control_status.flags.mag_3D = true;
} else {
// use heading fusion when on the ground
_control_status.flags.mag_hdg = true;
_control_status.flags.mag_2D = false;
_control_status.flags.mag_3D = false;
}
}
} else if (_params.mag_fusion_type == MAG_FUSE_TYPE_HEADING) {
// always use heading fusion
_control_status.flags.mag_hdg = true;
_control_status.flags.mag_2D = false;
_control_status.flags.mag_3D = false;
} else if (_params.mag_fusion_type == MAG_FUSE_TYPE_2D) {
// always use 2D mag fusion
_control_status.flags.mag_hdg = false;
_control_status.flags.mag_2D = true;
_control_status.flags.mag_3D = false;
} else if (_params.mag_fusion_type == MAG_FUSE_TYPE_3D) {
// if transitioning into 3-axis fusion mode, we need to initialise the yaw angle and field states
if (!_control_status.flags.mag_3D) {
_control_status.flags.yaw_align = resetMagHeading(_mag_sample_delayed.mag);
}
// always use 3-axis mag fusion
_control_status.flags.mag_hdg = false;
_control_status.flags.mag_2D = false;
_control_status.flags.mag_3D = true;
} else {
// do no magnetometer fusion at all
_control_status.flags.mag_hdg = false;
_control_status.flags.mag_2D = false;
_control_status.flags.mag_3D = false;
}
// if we are using 3-axis magnetometer fusion, but without external aiding, then the declination must be fused as an observation to prevent long term heading drift
// fusing declination when gps aiding is available is optional, but recommneded to prevent problem if the vehicle is static for extended periods of time
if (_control_status.flags.mag_3D && (!_control_status.flags.gps || (_params.mag_declination_source & MASK_FUSE_DECL))) {
_control_status.flags.mag_dec = true;
} else {
_control_status.flags.mag_dec = false;
}
// Control the soure of height measurements for the main filter
if ((_params.vdist_sensor_type == VDIST_SENSOR_BARO && !_baro_hgt_faulty) || _control_status.flags.baro_hgt) {
_control_status.flags.baro_hgt = true;
_control_status.flags.gps_hgt = false;
_control_status.flags.rng_hgt = false;
} else if ((_params.vdist_sensor_type == VDIST_SENSOR_GPS && !_gps_hgt_faulty) || _control_status.flags.gps_hgt) {
_control_status.flags.baro_hgt = false;
_control_status.flags.gps_hgt = true;
_control_status.flags.rng_hgt = false;
} else if (_params.vdist_sensor_type == VDIST_SENSOR_RANGE && !_rng_hgt_faulty) {
_control_status.flags.baro_hgt = false;
_control_status.flags.gps_hgt = false;
_control_status.flags.rng_hgt = true;
}
// Placeholder for control of wind velocity states estimation
// TODO add methods for true airspeed and/or sidelsip fusion or some type of drag force measurement
if (false) {
_control_status.flags.wind = false;
}
// Store the status to enable change detection
_control_status_prev.value = _control_status.value;
}
