/// 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 target_vel_length = target_vel.length();
if (target_vel_length != 0.0f) {
_spline_time_scale = _spline_vel_scaler/target_vel_length;
}
// update target position
_pos_control.set_pos_target(target_pos);
// update the yaw
_yaw = RadiansToCentiDegrees(fast_atan2(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;
}
}
}
/// advance_spline_target_along_track - move target location along track from origin to destination
bool 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);
_pos_delta_unit = target_vel/target_vel.length();
calculate_wp_leash_length();
// get current location
Vector3f curr_pos = _inav.get_position();
// get terrain altitude offset for origin and current position (i.e. change in terrain altitude from a position vs ekf origin)
float terr_offset = 0.0f;
if (_terrain_alt && !get_terrain_offset(terr_offset)) {
return false;
}
// calculate position error
Vector3f track_error = curr_pos - target_pos;
track_error.z -= terr_offset;
// 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
float 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 < 0.0f) {
track_leash_slack = 0.0f;
}
// update velocity
float spline_dist_to_wp = (_destination - target_pos).length();
float vel_limit = _wp_speed_cms;
if (!is_zero(dt)) {
vel_limit = MIN(vel_limit, track_leash_slack/dt);
}
// 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 < vel_limit) {
// increase velocity using acceleration
_spline_vel_scaler += _wp_accel_cms * dt;
}
// constrain target velocity
_spline_vel_scaler = constrain_float(_spline_vel_scaler, 0.0f, vel_limit);
// scale the spline_time by the velocity we've calculated vs the velocity that came out of the spline calculator
float target_vel_length = target_vel.length();
if (!is_zero(target_vel_length)) {
_spline_time_scale = _spline_vel_scaler/target_vel_length;
}
// update target position
target_pos.z += terr_offset;
_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;
}
}
return true;
}
/// advance_spline_target_along_track - move target location along track from origin to destination
bool 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);
// if target velocity is zero the origin and destination must be the same
// so flag reached destination (and protect against divide by zero)
float target_vel_length = target_vel.length();
if (is_zero(target_vel_length)) {
_flags.reached_destination = true;
return true;
}
_pos_delta_unit = target_vel / target_vel_length;
calculate_wp_leash_length();
// get current location
Vector3f curr_pos = _inav.get_position();
// get terrain altitude offset for origin and current position (i.e. change in terrain altitude from a position vs ekf origin)
float terr_offset = 0.0f;
if (_terrain_alt && !get_terrain_offset(terr_offset)) {
return false;
}
// calculate position error
Vector3f track_error = curr_pos - target_pos;
track_error.z -= terr_offset;
// calculate the horizontal error
_track_error_xy = norm(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
float 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 < 0.0f) {
track_leash_slack = 0.0f;
}
// update velocity
float spline_dist_to_wp = (_destination - target_pos).length();
float vel_limit = _wp_speed_cms;
if (!is_zero(dt)) {
vel_limit = MIN(vel_limit, track_leash_slack/dt);
}
// 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_cmss);
}else if(_spline_vel_scaler < vel_limit) {
// increase velocity using acceleration
_spline_vel_scaler += _wp_accel_cmss * dt;
}
// constrain target velocity
_spline_vel_scaler = constrain_float(_spline_vel_scaler, 0.0f, vel_limit);
// scale the spline_time by the velocity we've calculated vs the velocity that came out of the spline calculator
_spline_time_scale = _spline_vel_scaler / target_vel_length;
// update target position
target_pos.z += terr_offset;
_pos_control.set_pos_target(target_pos);
// update the target yaw if origin and destination are at least 2m apart horizontally
if (_track_length_xy >= WPNAV_YAW_DIST_MIN) {
if (_pos_control.get_leash_xy() < WPNAV_YAW_DIST_MIN) {
// if the leash is very short (i.e. flying at low speed) use the target point's velocity along the track
if (!is_zero(target_vel.x) && !is_zero(target_vel.y)) {
set_yaw_cd(RadiansToCentiDegrees(atan2f(target_vel.y,target_vel.x)));
}
} else {
// point vehicle along the leash (i.e. point vehicle towards target point on the segment from origin to destination)
float track_error_xy_length = safe_sqrt(sq(track_error.x)+sq(track_error.y));
if (track_error_xy_length > MIN(WPNAV_YAW_DIST_MIN, _pos_control.get_leash_xy()*WPNAV_YAW_LEASH_PCT_MIN)) {
// To-Do: why is track_error sign reversed?
set_yaw_cd(RadiansToCentiDegrees(atan2f(-track_error.y,-track_error.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;
}
}
return true;
}
