/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*- #include #include extern const AP_HAL::HAL& hal; const AP_Param::GroupInfo AC_WPNav::var_info[] PROGMEM = { // index 0 was used for the old orientation matrix // @Param: SPEED // @DisplayName: Waypoint Horizontal Speed Target // @Description: Defines the speed in cm/s which the aircraft will attempt to maintain horizontally during a WP mission // @Units: cm/s // @Range: 0 2000 // @Increment: 50 // @User: Standard AP_GROUPINFO("SPEED", 0, AC_WPNav, _wp_speed_cms, WPNAV_WP_SPEED), // @Param: RADIUS // @DisplayName: Waypoint Radius // @Description: Defines the distance from a waypoint, that when crossed indicates the wp has been hit. // @Units: cm // @Range: 100 1000 // @Increment: 1 // @User: Standard AP_GROUPINFO("RADIUS", 1, AC_WPNav, _wp_radius_cm, WPNAV_WP_RADIUS), // @Param: SPEED_UP // @DisplayName: Waypoint Climb Speed Target // @Description: Defines the speed in cm/s which the aircraft will attempt to maintain while climbing during a WP mission // @Units: cm/s // @Range: 0 1000 // @Increment: 50 // @User: Standard AP_GROUPINFO("SPEED_UP", 2, AC_WPNav, _wp_speed_up_cms, WPNAV_WP_SPEED_UP), // @Param: SPEED_DN // @DisplayName: Waypoint Descent Speed Target // @Description: Defines the speed in cm/s which the aircraft will attempt to maintain while descending during a WP mission // @Units: cm/s // @Range: 0 1000 // @Increment: 50 // @User: Standard AP_GROUPINFO("SPEED_DN", 3, AC_WPNav, _wp_speed_down_cms, WPNAV_WP_SPEED_DOWN), // @Param: LOIT_SPEED // @DisplayName: Loiter Horizontal Maximum Speed // @Description: Defines the maximum speed in cm/s which the aircraft will travel horizontally while in loiter mode // @Units: cm/s // @Range: 0 2000 // @Increment: 50 // @User: Standard AP_GROUPINFO("LOIT_SPEED", 4, AC_WPNav, _loiter_speed_cms, WPNAV_LOITER_SPEED), // @Param: ACCEL // @DisplayName: Waypoint Acceleration // @Description: Defines the horizontal acceleration in cm/s/s used during missions // @Units: cm/s/s // @Range: 50 500 // @Increment: 10 // @User: Standard AP_GROUPINFO("ACCEL", 5, AC_WPNav, _wp_accel_cms, WPNAV_ACCELERATION), // @Param: ACCEL_Z // @DisplayName: Waypoint Vertical Acceleration // @Description: Defines the vertical acceleration in cm/s/s used during missions // @Units: cm/s/s // @Range: 50 500 // @Increment: 10 // @User: Standard AP_GROUPINFO("ACCEL_Z", 6, AC_WPNav, _wp_accel_z_cms, WPNAV_WP_ACCEL_Z_DEFAULT), AP_GROUPEND }; // Default constructor. // Note that the Vector/Matrix constructors already implicitly zero // their values. // AC_WPNav::AC_WPNav(const AP_InertialNav* inav, const AP_AHRS* ahrs, AC_PosControl& pos_control) : _inav(inav), _ahrs(ahrs), _pos_control(pos_control), _loiter_last_update(0), _loiter_step(0), _pilot_accel_fwd_cms(0), _pilot_accel_rgt_cms(0), _loiter_accel_cms(WPNAV_LOITER_ACCEL), _wp_last_update(0), _wp_step(0), _track_length(0.0), _track_desired(0.0), _track_accel(0.0), _track_speed(0.0), _track_leash_length(0.0), _slow_down_dist(0.0), _spline_time(0.0), _spline_vel_scaler(0.0), _yaw(0.0) { AP_Param::setup_object_defaults(this, var_info); } /// /// loiter controller /// /// set_loiter_target in cm from home void AC_WPNav::set_loiter_target(const Vector3f& position, bool reset_I) { // if reset_I is false we warn position controller not to reset I terms if (!reset_I) { _pos_control.keep_xy_I_terms(); } // set target position _pos_control.set_pos_target(position); // initialise feed forward velocity to zero _pos_control.set_desired_velocity(0,0); // initialise pos controller speed _pos_control.set_speed_xy(_loiter_speed_cms); // initialise pos controller acceleration _loiter_accel_cms = _loiter_speed_cms/2.0f; _pos_control.set_accel_xy(_loiter_accel_cms); // initialise pilot input _pilot_accel_fwd_cms = 0; _pilot_accel_rgt_cms = 0; } /// init_loiter_target - initialize's loiter position and feed-forward velocity from current pos and velocity void AC_WPNav::init_loiter_target() { Vector3f curr_vel = _inav->get_velocity(); // initialise pos controller speed and acceleration _pos_control.set_speed_xy(_loiter_speed_cms); _loiter_accel_cms = _loiter_speed_cms/2.0f; _pos_control.set_accel_xy(_loiter_accel_cms); // set target position _pos_control.set_target_to_stopping_point_xy(); // initialise feed forward velocities to zero _pos_control.set_desired_velocity(curr_vel.x, curr_vel.y); // initialise pilot input _pilot_accel_fwd_cms = 0; _pilot_accel_rgt_cms = 0; } /// set_loiter_velocity - allows main code to pass the maximum velocity for loiter void AC_WPNav::set_loiter_velocity(float velocity_cms) { // range check velocity and update position controller if (velocity_cms >= WPNAV_LOITER_SPEED_MIN) { _loiter_speed_cms = velocity_cms; // initialise pos controller speed _pos_control.set_speed_xy(_loiter_speed_cms); // initialise pos controller acceleration _loiter_accel_cms = _loiter_speed_cms/2.0f; _pos_control.set_accel_xy(_loiter_accel_cms); } } /// set_pilot_desired_acceleration - sets pilot desired acceleration from roll and pitch stick input void AC_WPNav::set_pilot_desired_acceleration(float control_roll, float control_pitch) { // convert pilot input to desired acceleration in cm/s/s _pilot_accel_fwd_cms = -control_pitch * _loiter_accel_cms / 4500.0f; _pilot_accel_rgt_cms = control_roll * _loiter_accel_cms / 4500.0f; } /// get_loiter_stopping_point_xy - returns vector to stopping point based on a horizontal position and velocity void AC_WPNav::get_loiter_stopping_point_xy(Vector3f& stopping_point) const { _pos_control.get_stopping_point_xy(stopping_point); } /// calc_loiter_desired_velocity - updates desired velocity (i.e. feed forward) with pilot requested acceleration and fake wind resistance /// updated velocity sent directly to position controller void AC_WPNav::calc_loiter_desired_velocity(float nav_dt) { // range check nav_dt if( nav_dt < 0 ) { return; } // check loiter speed and avoid divide by zero if( _loiter_speed_cms < WPNAV_LOITER_SPEED_MIN) { _loiter_speed_cms = WPNAV_LOITER_SPEED_MIN; _loiter_accel_cms = _loiter_speed_cms/2.0f; } // rotate pilot input to lat/lon frame Vector2f desired_accel; desired_accel.x = (_pilot_accel_fwd_cms*_ahrs->cos_yaw() - _pilot_accel_rgt_cms*_ahrs->sin_yaw()); desired_accel.y = (_pilot_accel_fwd_cms*_ahrs->sin_yaw() + _pilot_accel_rgt_cms*_ahrs->cos_yaw()); // get pos_control's feed forward velocity Vector2f desired_vel = _pos_control.get_desired_velocity(); // add pilot commanded acceleration desired_vel += desired_accel * nav_dt; // reduce velocity with fake wind resistance if(desired_vel.x > 0 ) { desired_vel.x -= (_loiter_accel_cms-WPNAV_LOITER_ACCEL_MIN)*nav_dt*desired_vel.x/_loiter_speed_cms; desired_vel.x = max(desired_vel.x - WPNAV_LOITER_ACCEL_MIN*nav_dt, 0); }else if(desired_vel.x < 0) { desired_vel.x -= (_loiter_accel_cms-WPNAV_LOITER_ACCEL_MIN)*nav_dt*desired_vel.x/_loiter_speed_cms; desired_vel.x = min(desired_vel.x + WPNAV_LOITER_ACCEL_MIN*nav_dt, 0); } if(desired_vel.y > 0 ) { desired_vel.y -= (_loiter_accel_cms-WPNAV_LOITER_ACCEL_MIN)*nav_dt*desired_vel.y/_loiter_speed_cms; desired_vel.y = max(desired_vel.y - WPNAV_LOITER_ACCEL_MIN*nav_dt, 0); }else if(desired_vel.y < 0) { desired_vel.y -= (_loiter_accel_cms-WPNAV_LOITER_ACCEL_MIN)*nav_dt*desired_vel.y/_loiter_speed_cms; desired_vel.y = min(desired_vel.y + WPNAV_LOITER_ACCEL_MIN*nav_dt, 0); } // constrain and scale the feed forward velocity if necessary float vel_total = pythagorous2(desired_vel.x, desired_vel.y); if (vel_total > _loiter_speed_cms && vel_total > 0.0f) { desired_vel.x = _loiter_speed_cms * desired_vel.x/vel_total; desired_vel.y = _loiter_speed_cms * desired_vel.y/vel_total; } // send adjusted feed forward velocity back to position controller _pos_control.set_desired_velocity(desired_vel.x,desired_vel.y); } /// get_bearing_to_target - get bearing to loiter target in centi-degrees int32_t AC_WPNav::get_loiter_bearing_to_target() const { return get_bearing_cd(_inav->get_position(), _pos_control.get_pos_target()); } /// update_loiter - run the loiter controller - should be called at 100hz void AC_WPNav::update_loiter() { // calculate dt uint32_t now = hal.scheduler->millis(); float dt = (now - _loiter_last_update) / 1000.0f; // reset step back to 0 if 0.1 seconds has passed and we completed the last full cycle if (dt >= WPNAV_LOITER_UPDATE_TIME) { // double check dt is reasonable if (dt >= 1.0f) { dt = 0.0; } // capture time since last iteration _loiter_last_update = now; // translate any adjustments from pilot to loiter target calc_loiter_desired_velocity(dt); // trigger position controller on next update _pos_control.trigger_xy(); }else{ // run horizontal position controller _pos_control.update_xy_controller(true); } } /// /// waypoint navigation /// /// set_speed_xy - allows main code to pass target horizontal velocity for wp navigation void AC_WPNav::set_speed_xy(float speed_cms) { // range check new target speed and update position controller if (_wp_speed_cms >= WPNAV_WP_SPEED_MIN) { _wp_speed_cms = speed_cms; _pos_control.set_speed_xy(_wp_speed_cms); // flag that wp leash must be recalculated _flags.recalc_wp_leash = true; } } /// set_destination - set destination using cm from home void AC_WPNav::set_wp_destination(const Vector3f& destination) { Vector3f origin; // if waypoint controller is active use the existing position target as the origin if ((hal.scheduler->millis() - _wp_last_update) < 1000) { origin = _pos_control.get_pos_target(); } else { // if waypoint controller is not active, set origin to reasonable stopping point (using curr pos and velocity) _pos_control.get_stopping_point_xy(origin); _pos_control.get_stopping_point_z(origin); } // set origin and destination set_wp_origin_and_destination(origin, destination); } /// set_origin_and_destination - set origin and destination using lat/lon coordinates void AC_WPNav::set_wp_origin_and_destination(const Vector3f& origin, const Vector3f& destination) { // store origin and destination locations _origin = origin; _destination = destination; Vector3f pos_delta = _destination - _origin; _track_length = pos_delta.length(); // get track length // calculate each axis' percentage of the total distance to the destination if (_track_length == 0.0f) { // avoid possible divide by zero _pos_delta_unit.x = 0; _pos_delta_unit.y = 0; _pos_delta_unit.z = 0; }else{ _pos_delta_unit = pos_delta/_track_length; } // check _wp_accel_cms is reasonable if (_wp_accel_cms <= 0) { _wp_accel_cms.set_and_save(WPNAV_ACCELERATION); } // initialise position controller speed and acceleration _pos_control.set_speed_xy(_wp_speed_cms); _pos_control.set_accel_xy(_wp_accel_cms); _pos_control.set_speed_z(-_wp_speed_down_cms, _wp_speed_up_cms); _pos_control.set_accel_z(_wp_accel_z_cms); _pos_control.calc_leash_length_xy(); _pos_control.calc_leash_length_z(); // calculate leash lengths calculate_wp_leash_length(); // initialise yaw heading _yaw = get_bearing_cd(_origin, _destination); // initialise intermediate point to the origin _pos_control.set_pos_target(origin); _track_desired = 0; // target is at beginning of track _flags.reached_destination = false; _flags.fast_waypoint = false; // default waypoint back to slow _flags.slowing_down = false; // target is not slowing down yet _flags.segment_type = SEGMENT_STRAIGHT; // initialise the limited speed to current speed along the track const Vector3f &curr_vel = _inav->get_velocity(); // get speed along track (note: we convert vertical speed into horizontal speed equivalent) float speed_along_track = curr_vel.x * _pos_delta_unit.x + curr_vel.y * _pos_delta_unit.y + curr_vel.z * _pos_delta_unit.z; _limited_speed_xy_cms = constrain_float(speed_along_track,0,_wp_speed_cms); } /// get_wp_stopping_point_xy - returns vector to stopping point based on a horizontal position and velocity void AC_WPNav::get_wp_stopping_point_xy(Vector3f& stopping_point) const { _pos_control.get_stopping_point_xy(stopping_point); } /// advance_wp_target_along_track - move target location along track from origin to destination void AC_WPNav::advance_wp_target_along_track(float dt) { float track_covered; // distance (in cm) along the track that the vehicle has traveled. Measured by drawing a perpendicular line from the track to the vehicle. Vector3f track_error; // distance error (in cm) from the track_covered position (i.e. closest point on the line to the vehicle) and the vehicle float track_desired_max; // the farthest distance (in cm) along the track that the leash will allow float track_desired_temp = _track_desired; float track_leash_slack; // additional distance (in cm) along the track from our track_covered position that our leash will allow bool reached_leash_limit = false; // true when track has reached leash limit and we need to slow down the target point // get current location Vector3f curr_pos = _inav->get_position(); Vector3f curr_delta = curr_pos - _origin; // calculate how far along the track we are track_covered = curr_delta.x * _pos_delta_unit.x + curr_delta.y * _pos_delta_unit.y + curr_delta.z * _pos_delta_unit.z; Vector3f track_covered_pos = _pos_delta_unit * track_covered; track_error = curr_delta - track_covered_pos; // calculate the horizontal error float track_error_xy = pythagorous2(track_error.x, track_error.y); // calculate the vertical error float track_error_z = fabsf(track_error.z); // get position control leash lengths float leash_xy = _pos_control.get_leash_xy(); float leash_z; if (track_error.z >= 0) { leash_z = _pos_control.get_leash_up_z(); }else{ leash_z = _pos_control.get_leash_down_z(); } // calculate how far along the track we could move the intermediate target before reaching the end of the leash track_leash_slack = min(_track_leash_length*(leash_z-track_error_z)/leash_z, _track_leash_length*(leash_xy-track_error_xy)/leash_xy); if (track_leash_slack < 0) { track_desired_max = track_covered; }else{ track_desired_max = track_covered + track_leash_slack; } // check if target is already beyond the leash if (_track_desired > track_desired_max) { reached_leash_limit = true; } // get current velocity const Vector3f &curr_vel = _inav->get_velocity(); // get speed along track float speed_along_track = curr_vel.x * _pos_delta_unit.x + curr_vel.y * _pos_delta_unit.y + curr_vel.z * _pos_delta_unit.z; // calculate point at which velocity switches from linear to sqrt float linear_velocity = _wp_speed_cms; float kP = _pos_control.get_pos_xy_kP(); if (kP >= 0.0f) { // avoid divide by zero linear_velocity = _track_accel/kP; } // let the limited_speed_xy_cms be some range above or below current velocity along track if (speed_along_track < -linear_velocity) { // we are traveling fast in the opposite direction of travel to the waypoint so do not move the intermediate point _limited_speed_xy_cms = 0; }else{ // increase intermediate target point's velocity if not yet at the leash limit if(dt > 0 && !reached_leash_limit) { _limited_speed_xy_cms += 2.0f * _track_accel * dt; } // do not allow speed to be below zero or over top speed _limited_speed_xy_cms = constrain_float(_limited_speed_xy_cms, 0.0f, _track_speed); // check if we should begin slowing down if (!_flags.fast_waypoint) { float dist_to_dest = _track_length - _track_desired; if (!_flags.slowing_down && dist_to_dest <= _slow_down_dist) { _flags.slowing_down = true; } // if target is slowing down, limit the speed if (_flags.slowing_down) { _limited_speed_xy_cms = min(_limited_speed_xy_cms, get_slow_down_speed(dist_to_dest, _track_accel)); } } // if our current velocity is within the linear velocity range limit the intermediate point's velocity to be no more than the linear_velocity above or below our current velocity if (fabsf(speed_along_track) < linear_velocity) { _limited_speed_xy_cms = constrain_float(_limited_speed_xy_cms,speed_along_track-linear_velocity,speed_along_track+linear_velocity); } } // advance the current target if (!reached_leash_limit) { track_desired_temp += _limited_speed_xy_cms * dt; } // do not let desired point go past the end of the segment track_desired_temp = constrain_float(track_desired_temp, 0, _track_length); // set our new desired position on track _track_desired = max(_track_desired, track_desired_temp); // recalculate the desired position _pos_control.set_pos_target(_origin + _pos_delta_unit * _track_desired); // check if we've reached the waypoint if( !_flags.reached_destination ) { if( _track_desired >= _track_length ) { // "fast" waypoints are complete once the intermediate point reaches the destination if (_flags.fast_waypoint) { _flags.reached_destination = true; }else{ // regular waypoints also require the copter to be within the waypoint radius Vector3f dist_to_dest = curr_pos - _destination; if( dist_to_dest.length() <= _wp_radius_cm ) { _flags.reached_destination = true; } } } } } /// get_wp_distance_to_destination - get horizontal distance to destination in cm float AC_WPNav::get_wp_distance_to_destination() const { // get current location Vector3f curr = _inav->get_position(); return pythagorous2(_destination.x-curr.x,_destination.y-curr.y); } /// get_wp_bearing_to_destination - get bearing to next waypoint in centi-degrees int32_t AC_WPNav::get_wp_bearing_to_destination() const { return get_bearing_cd(_inav->get_position(), _destination); } /// update_wpnav - run the wp controller - should be called at 100hz or higher void AC_WPNav::update_wpnav() { // calculate dt uint32_t now = hal.scheduler->millis(); float dt = (now - _wp_last_update) / 1000.0f; // reset step back to 0 if 0.1 seconds has passed and we completed the last full cycle if (dt >= WPNAV_WP_UPDATE_TIME) { // double check dt is reasonable if (dt >= 1.0f) { dt = 0.0; } // capture time since last iteration _wp_last_update = now; // advance the target if necessary advance_wp_target_along_track(dt); _pos_control.trigger_xy(); }else{ // run horizontal position controller _pos_control.update_xy_controller(false); // check if leash lengths need updating check_wp_leash_length(); } } // check_wp_leash_length - check if waypoint leash lengths need to be recalculated // should be called after _pos_control.update_xy_controller which may have changed the position controller leash lengths void AC_WPNav::check_wp_leash_length() { // exit immediately if recalc is not required if (_flags.recalc_wp_leash) { calculate_wp_leash_length(); } } /// calculate_wp_leash_length - calculates horizontal and vertical leash lengths for waypoint controller void AC_WPNav::calculate_wp_leash_length() { // length of the unit direction vector in the horizontal float pos_delta_unit_xy = pythagorous2(_pos_delta_unit.x, _pos_delta_unit.y); float pos_delta_unit_z = fabsf(_pos_delta_unit.z); float speed_z; float leash_z; if (_pos_delta_unit.z >= 0) { speed_z = _wp_speed_up_cms; leash_z = _pos_control.get_leash_up_z(); }else{ speed_z = _wp_speed_down_cms; leash_z = _pos_control.get_leash_down_z(); } // calculate the maximum acceleration, maximum velocity, and leash length in the direction of travel if(pos_delta_unit_z == 0 && pos_delta_unit_xy == 0){ _track_accel = 0; _track_speed = 0; _track_leash_length = WPNAV_LEASH_LENGTH_MIN; }else if(_pos_delta_unit.z == 0){ _track_accel = _wp_accel_cms/pos_delta_unit_xy; _track_speed = _wp_speed_cms/pos_delta_unit_xy; _track_leash_length = _pos_control.get_leash_xy()/pos_delta_unit_xy; }else if(pos_delta_unit_xy == 0){ _track_accel = _wp_accel_z_cms/pos_delta_unit_z; _track_speed = speed_z/pos_delta_unit_z; _track_leash_length = leash_z/pos_delta_unit_z; }else{ _track_accel = min(_wp_accel_z_cms/pos_delta_unit_z, _wp_accel_cms/pos_delta_unit_xy); _track_speed = min(speed_z/pos_delta_unit_z, _wp_speed_cms/pos_delta_unit_xy); _track_leash_length = min(leash_z/pos_delta_unit_z, _pos_control.get_leash_xy()/pos_delta_unit_xy); } // calculate slow down distance (the distance from the destination when the target point should begin to slow down) calc_slow_down_distance(_track_speed, _track_accel); // set recalc leash flag to false _flags.recalc_wp_leash = false; } /// /// spline methods /// /// set_spline_destination waypoint using position vector (distance from home in cm) /// stopped_at_start should be set to true if vehicle is stopped at the origin /// seg_end_type should be set to stopped, straight or spline depending upon the next segment's type /// next_destination should be set to the next segment's destination if the seg_end_type is SEGMENT_END_STRAIGHT or SEGMENT_END_SPLINE void AC_WPNav::set_spline_destination(const Vector3f& destination, bool stopped_at_start, spline_segment_end_type seg_end_type, const Vector3f& next_destination) { Vector3f origin; // if waypoint controller is active and copter has reached the previous waypoint use it for the origin if( _flags.reached_destination && ((hal.scheduler->millis() - _wp_last_update) < 1000) ) { origin = _destination; }else{ // otherwise calculate origin from the current position and velocity _pos_control.get_stopping_point_xy(origin); _pos_control.get_stopping_point_z(origin); } // set origin and destination set_spline_origin_and_destination(origin, destination, stopped_at_start, seg_end_type, next_destination); } /// set_spline_origin_and_destination - set origin and destination waypoints using position vectors (distance from home in cm) /// seg_type should be calculated by calling function based on the mission void AC_WPNav::set_spline_origin_and_destination(const Vector3f& origin, const Vector3f& destination, bool stopped_at_start, spline_segment_end_type seg_end_type, const Vector3f& next_destination) { // mission is "active" if wpnav has been called recently and vehicle reached the previous waypoint bool prev_segment_exists = (_flags.reached_destination && ((hal.scheduler->millis() - _wp_last_update) < 1000)); // check _wp_accel_cms is reasonable to avoid divide by zero if (_wp_accel_cms <= 0) { _wp_accel_cms.set_and_save(WPNAV_ACCELERATION); } // segment start types // stop - vehicle is not moving at origin // straight-fast - vehicle is moving, previous segment is straight. vehicle will fly straight through the waypoint before beginning it's spline path to the next wp // _flag.segment_type holds whether prev segment is straight vs spline but we don't know if it has a delay // spline-fast - vehicle is moving, previous segment is splined, vehicle will fly through waypoint but previous segment should have it flying in the correct direction (i.e. exactly parallel to position difference vector from previous segment's origin to this segment's destination) // calculate spline velocity at origin if (stopped_at_start || !prev_segment_exists) { // if vehicle is stopped at the origin, set origin velocity to 0.1 * distance vector from origin to destination _spline_origin_vel = (destination - origin) * 0.1f; _spline_time = 0.0f; _spline_vel_scaler = 0.0f; }else{ // look at previous segment to determine velocity at origin if (_flags.segment_type == SEGMENT_STRAIGHT) { // previous segment is straight, vehicle is moving so vehicle should fly straight through the origin // before beginning it's spline path to the next waypoint. Note: we are using the previous segment's origin and destination _spline_origin_vel = (_destination - _origin); _spline_time = 0.0f; // To-Do: this should be set based on how much overrun there was from straight segment? _spline_vel_scaler = 0.0f; // To-Do: this should be set based on speed at end of prev straight segment? }else{ // previous segment is splined, vehicle will fly through origin // we can use the previous segment's destination velocity as this segment's origin velocity // Note: previous segment will leave destination velocity parallel to position difference vector // from previous segment's origin to this segment's destination) _spline_origin_vel = _spline_destination_vel; if (_spline_time > 1.0f && _spline_time < 1.1f) { // To-Do: remove hard coded 1.1f _spline_time -= 1.0f; }else{ _spline_time = 0.0f; } _spline_vel_scaler = 0.0f; } } // calculate spline velocity at destination switch (seg_end_type) { case SEGMENT_END_STOP: // if vehicle stops at the destination set destination velocity to 0.1 * distance vector from origin to destination _spline_destination_vel = (destination - origin) * 0.1f; _flags.fast_waypoint = false; break; case SEGMENT_END_STRAIGHT: // if next segment is straight, vehicle's final velocity should face along the next segment's position _spline_destination_vel = (next_destination - destination); _flags.fast_waypoint = true; break; case SEGMENT_END_SPLINE: // if next segment is splined, vehicle's final velocity should face parallel to the line from the origin to the next destination _spline_destination_vel = (next_destination - origin); _flags.fast_waypoint = true; break; } // code below ensures we don't get too much overshoot when the next segment is short float vel_len = (_spline_origin_vel + _spline_destination_vel).length(); float pos_len = (destination - origin).length() * 4.0f; if (vel_len > pos_len) { // if total start+stop velocity is more than twice position difference // use a scaled down start and stop velocityscale the start and stop velocities down float vel_scaling = pos_len / vel_len; // update spline calculator update_spline_solution(origin, destination, _spline_origin_vel * vel_scaling, _spline_destination_vel * vel_scaling); }else{ // update spline calculator update_spline_solution(origin, destination, _spline_origin_vel, _spline_destination_vel); } // initialise yaw heading to current heading _yaw = _ahrs->yaw_sensor; // store origin and destination locations _origin = origin; _destination = destination; // initialise position controller speed and acceleration _pos_control.set_speed_xy(_wp_speed_cms); _pos_control.set_accel_xy(_wp_accel_cms); _pos_control.set_speed_z(-_wp_speed_down_cms, _wp_speed_up_cms); _pos_control.calc_leash_length_xy(); _pos_control.calc_leash_length_z(); // calculate slow down distance calc_slow_down_distance(_wp_speed_cms, _wp_accel_cms); // initialise intermediate point to the origin _pos_control.set_pos_target(origin); _flags.reached_destination = false; _flags.segment_type = SEGMENT_SPLINE; } /// update_spline - update spline controller void AC_WPNav::update_spline() { // exit immediately if this is not a spline segment if (_flags.segment_type != SEGMENT_SPLINE) { return; } // calculate dt uint32_t now = hal.scheduler->millis(); float dt = (now - _wp_last_update) / 1000.0f; // reset step back to 0 if 0.1 seconds has passed and we completed the last full cycle if (dt >= WPNAV_WP_UPDATE_TIME) { // double check dt is reasonable if (dt >= 1.0f) { dt = 0.0; } // capture time since last iteration _wp_last_update = now; // advance the target if necessary advance_spline_target_along_track(dt); _pos_control.trigger_xy(); }else{ // run horizontal position controller _pos_control.update_xy_controller(false); } } /// update_spline_solution - recalculates hermite_spline_solution grid /// relies on _spline_origin_vel, _spline_destination_vel and _origin and _destination void AC_WPNav::update_spline_solution(const Vector3f& origin, const Vector3f& dest, const Vector3f& origin_vel, const Vector3f& dest_vel) { _hermite_spline_solution[0] = origin; _hermite_spline_solution[1] = origin_vel; _hermite_spline_solution[2] = -origin*3.0f -origin_vel*2.0f + dest*3.0f - dest_vel; _hermite_spline_solution[3] = origin*2.0f + origin_vel -dest*2.0f + dest_vel; } /// advance_spline_target_along_track - move target location along track from origin to destination void AC_WPNav::advance_spline_target_along_track(float dt) { if (!_flags.reached_destination) { Vector3f target_pos, target_vel; // update target position and velocity from spline calculator calc_spline_pos_vel(_spline_time, target_pos, target_vel); // update velocity float spline_dist_to_wp = (_destination - target_pos).length(); // if within the stopping distance from destination, set target velocity to sqrt of distance * 2 * acceleration if (!_flags.fast_waypoint && spline_dist_to_wp < _slow_down_dist) { _spline_vel_scaler = safe_sqrt(spline_dist_to_wp * 2.0f * _wp_accel_cms); }else if(_spline_vel_scaler < _wp_speed_cms) { // increase velocity using acceleration // To-Do: replace 0.1f below with update frequency passed in from main program _spline_vel_scaler += _wp_accel_cms* 0.1f; } // constrain target velocity if (_spline_vel_scaler > _wp_speed_cms) { _spline_vel_scaler = _wp_speed_cms; } // scale the spline_time by the velocity we've calculated vs the velocity that came out of the spline calculator float spline_time_scale = _spline_vel_scaler/target_vel.length(); // update target position _pos_control.set_pos_target(target_pos); // update the yaw _yaw = RadiansToCentiDegrees(atan2f(target_vel.y,target_vel.x)); // advance spline time to next step _spline_time += spline_time_scale*dt; // we will reach the next waypoint in the next step so set reached_destination flag // To-Do: is this one step too early? if (_spline_time >= 1.0f) { _flags.reached_destination = true; } } } // calc_spline_pos_vel_accel - calculates target position, velocity and acceleration for the given "spline_time" /// relies on update_spline_solution being called when the segment's origin and destination were set void AC_WPNav::calc_spline_pos_vel(float spline_time, Vector3f& position, Vector3f& velocity) { float spline_time_sqrd = spline_time * spline_time; float spline_time_cubed = spline_time_sqrd * spline_time; position = _hermite_spline_solution[0] + \ _hermite_spline_solution[1] * spline_time + \ _hermite_spline_solution[2] * spline_time_sqrd + \ _hermite_spline_solution[3] * spline_time_cubed; velocity = _hermite_spline_solution[1] + \ _hermite_spline_solution[2] * 2.0f * spline_time + \ _hermite_spline_solution[3] * 3.0f * spline_time_sqrd; } /// /// shared methods /// // get_bearing_cd - return bearing in centi-degrees between two positions // To-Do: move this to math library float AC_WPNav::get_bearing_cd(const Vector3f &origin, const Vector3f &destination) const { float bearing = 9000 + atan2f(-(destination.x-origin.x), destination.y-origin.y) * 5729.57795f; if (bearing < 0) { bearing += 36000; } return bearing; } /// calc_slow_down_distance - calculates distance before waypoint that target point should begin to slow-down assuming it is travelling at full speed void AC_WPNav::calc_slow_down_distance(float speed_cms, float accel_cmss) { // To-Do: should we use a combination of horizontal and vertical speeds? // To-Do: update this automatically when speed or acceleration is changed _slow_down_dist = speed_cms * speed_cms / (4.0f*accel_cmss); } /// get_slow_down_speed - returns target speed of target point based on distance from the destination (in cm) float AC_WPNav::get_slow_down_speed(float dist_from_dest_cm, float accel_cmss) { // return immediately if distance is zero (or less) if (dist_from_dest_cm <= 0) { return WPNAV_WP_TRACK_SPEED_MIN; } // calculate desired speed near destination float target_speed = safe_sqrt(dist_from_dest_cm * 4.0f * accel_cmss); // ensure desired speed never becomes too low if (target_speed < WPNAV_WP_TRACK_SPEED_MIN) { return WPNAV_WP_TRACK_SPEED_MIN; } else { return target_speed; } }