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AC_WP_Nav: Convert S-Curves to use maximum Snap to remove minimum time between waypoints

This commit is contained in:
Leonard Hall 2022-03-03 09:23:11 +10:30 committed by Randy Mackay
parent a8b86e9c45
commit 5fa37e253e
2 changed files with 16 additions and 16 deletions
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26
libraries/AC_WPNav/AC_WPNav.cpp
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@ -177,7 +177,7 @@ void AC_WPNav::wp_and_spline_init(float speed_cms)
if (!is_positive(_wp_jerk)) {
_wp_jerk = _wp_accel_cmss;
}
calc_scurve_jerk_and_jerk_time();
calc_scurve_jerk_and_snap();
_scurve_prev_leg.init();
_scurve_this_leg.init();
@ -334,7 +334,7 @@ bool AC_WPNav::set_wp_destination(const Vector3f& destination, bool terrain_alt)
_scurve_this_leg.calculate_track(_origin, _destination,
_pos_control.get_max_speed_xy_cms(), _pos_control.get_max_speed_up_cms(), _pos_control.get_max_speed_down_cms(),
_wp_accel_cmss, _wp_accel_z_cmss,
_scurve_jerk_time, _scurve_jerk * 100.0f);
_scurve_snap * 100.0f, _scurve_jerk * 100.0f);
if (!is_zero(origin_speed)) {
// rebuild start of scurve if we have a non-zero origin speed
_scurve_this_leg.set_origin_speed_max(origin_speed);
@ -362,7 +362,7 @@ bool AC_WPNav::set_wp_destination_next(const Vector3f& destination, bool terrain
_scurve_next_leg.calculate_track(_destination, destination,
_pos_control.get_max_speed_xy_cms(), _pos_control.get_max_speed_up_cms(), _pos_control.get_max_speed_down_cms(),
_wp_accel_cmss, _wp_accel_z_cmss,
_scurve_jerk_time, _scurve_jerk * 100.0f);
_scurve_snap * 100.0f, _scurve_jerk * 100.0);
if (_this_leg_is_spline) {
const float this_leg_dest_speed_max = _spline_this_leg.get_destination_speed_max();
const float next_leg_origin_speed_max = _scurve_next_leg.set_origin_speed_max(this_leg_dest_speed_max);
@ -857,8 +857,8 @@ bool AC_WPNav::get_vector_NEU(const Location &loc, Vector3f &vec, bool &terrain_
}
// helper function to calculate scurve jerk and jerk_time values
// updates _scurve_jerk and _scurve_jerk_time
void AC_WPNav::calc_scurve_jerk_and_jerk_time()
// updates _scurve_jerk and _scurve_snap
void AC_WPNav::calc_scurve_jerk_and_snap()
{
// calculate jerk
_scurve_jerk = MIN(_attitude_control.get_ang_vel_roll_max_rads() * GRAVITY_MSS, _attitude_control.get_ang_vel_pitch_max_rads() * GRAVITY_MSS);
@ -868,14 +868,14 @@ void AC_WPNav::calc_scurve_jerk_and_jerk_time()
_scurve_jerk = MIN(_scurve_jerk, _wp_jerk);
}
// calculate jerk time
// Jounce (the rate of change of jerk) uses the attitude control input time constant because multicopters
// calculate maximum snap
// Snap (the rate of change of jerk) uses the attitude control input time constant because multicopters
// lean to accelerate. This means the change in angle is equivalent to the change in acceleration
const float jounce = MIN(_attitude_control.get_accel_roll_max_radss() * GRAVITY_MSS, _attitude_control.get_accel_pitch_max_radss() * GRAVITY_MSS);
if (is_positive(jounce)) {
_scurve_jerk_time = MAX(_attitude_control.get_input_tc(), 0.5f * _scurve_jerk * M_PI / jounce);
} else {
_scurve_jerk_time = MAX(_attitude_control.get_input_tc(), 0.1f);
_scurve_snap = (_scurve_jerk * M_PI) / (2.0 * MAX(_attitude_control.get_input_tc(), 0.1f));
const float snap = MIN(_attitude_control.get_accel_roll_max_radss(), _attitude_control.get_accel_pitch_max_radss()) * GRAVITY_MSS;
if (is_positive(snap)) {
_scurve_snap = MIN(_scurve_snap, snap);
}
_scurve_jerk_time *= 2.0f;
// reduce maximum snap by a factor of two from what the aircraft is capable of
_scurve_snap *= 0.5;
}

6
libraries/AC_WPNav/AC_WPNav.h
View File

@ -213,8 +213,8 @@ protected:
} _flags;
// helper function to calculate scurve jerk and jerk_time values
// updates _scurve_jerk and _scurve_jerk_time
void calc_scurve_jerk_and_jerk_time();
// updates _scurve_jerk and _scurve_snap
void calc_scurve_jerk_and_snap();
// references and pointers to external libraries
const AP_InertialNav& _inav;
@ -241,7 +241,7 @@ protected:
SCurve _scurve_this_leg; // current scurve trajectory
SCurve _scurve_next_leg; // next scurve trajectory used to blend with current scurve trajectory
float _scurve_jerk; // scurve jerk max in m/s/s/s
float _scurve_jerk_time; // scurve jerk time (time in seconds for jerk to increase from zero _scurve_jerk)
float _scurve_snap; // scurve snap in m/s/s/s/s
// spline curves
SplineCurve _spline_this_leg; // spline curve for current segment