/*
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see .
*/
#include "AC_Avoidance_config.h"
#if AP_AVOIDANCE_ENABLED
#include "AC_Avoid.h"
#include // AHRS library
#include // Failsafe fence library
#include
#include
#include
#include
#include
#if !APM_BUILD_TYPE(APM_BUILD_ArduPlane)
#if APM_BUILD_TYPE(APM_BUILD_Rover)
# define AP_AVOID_BEHAVE_DEFAULT AC_Avoid::BehaviourType::BEHAVIOR_STOP
#else
# define AP_AVOID_BEHAVE_DEFAULT AC_Avoid::BehaviourType::BEHAVIOR_SLIDE
#endif
#if APM_BUILD_COPTER_OR_HELI
# define AP_AVOID_ENABLE_Z 1
#endif
const AP_Param::GroupInfo AC_Avoid::var_info[] = {
// @Param: ENABLE
// @DisplayName: Avoidance control enable/disable
// @Description: Enabled/disable avoidance input sources
// @Bitmask: 0:UseFence,1:UseProximitySensor,2:UseBeaconFence
// @User: Standard
AP_GROUPINFO_FLAGS("ENABLE", 1, AC_Avoid, _enabled, AC_AVOID_DEFAULT, AP_PARAM_FLAG_ENABLE),
// 2 was ANGLE_MAX (in centi-degrees)
// @Param{Copter}: DIST_MAX
// @DisplayName: Avoidance distance maximum in non-GPS flight modes
// @Description: Distance from object at which obstacle avoidance will begin in non-GPS modes
// @Units: m
// @Range: 1 30
// @User: Standard
AP_GROUPINFO_FRAME("DIST_MAX", 3, AC_Avoid, _dist_max_m, AC_AVOID_NONGPS_DIST_MAX_DEFAULT, AP_PARAM_FRAME_COPTER | AP_PARAM_FRAME_HELI | AP_PARAM_FRAME_TRICOPTER),
// @Param: MARGIN
// @DisplayName: Avoidance distance margin in GPS modes
// @Description: Vehicle will attempt to stay at least this distance (in meters) from objects while in GPS modes
// @Units: m
// @Range: 1 10
// @User: Standard
AP_GROUPINFO("MARGIN", 4, AC_Avoid, _margin_m, 2.0f),
// @Param{Copter, Rover}: BEHAVE
// @DisplayName: Avoidance behaviour
// @Description: Avoidance behaviour (slide or stop)
// @Values: 0:Slide,1:Stop
// @User: Standard
AP_GROUPINFO_FRAME("BEHAVE", 5, AC_Avoid, _behavior, AP_AVOID_BEHAVE_DEFAULT, AP_PARAM_FRAME_COPTER | AP_PARAM_FRAME_HELI | AP_PARAM_FRAME_TRICOPTER | AP_PARAM_FRAME_ROVER),
// @Param: BACKUP_SPD
// @DisplayName: Avoidance maximum horizontal backup speed
// @Description: Maximum speed that will be used to back away from obstacles horizontally in position control modes (m/s). Set zero to disable horizontal backup.
// @Units: m/s
// @Range: 0 2
// @User: Standard
AP_GROUPINFO("BACKUP_SPD", 6, AC_Avoid, _backup_speed_max_ne_ms, 0.75f),
// @Param{Copter}: ALT_MIN
// @DisplayName: Avoidance minimum altitude
// @Description: Minimum altitude above which proximity based avoidance will start working. This requires a valid downward facing rangefinder reading to work. Set zero to disable
// @Units: m
// @Range: 0 6
// @User: Standard
AP_GROUPINFO_FRAME("ALT_MIN", 7, AC_Avoid, _alt_min_m, 0.0f, AP_PARAM_FRAME_COPTER | AP_PARAM_FRAME_HELI | AP_PARAM_FRAME_TRICOPTER),
// @Param: ACCEL_MAX
// @DisplayName: Avoidance maximum acceleration
// @Description: Maximum acceleration with which obstacles will be avoided with. Set zero to disable acceleration limits
// @Units: m/s/s
// @Range: 0 9
// @User: Standard
AP_GROUPINFO("ACCEL_MAX", 8, AC_Avoid, _accel_max_mss, 3.0f),
// @Param: BACKUP_DZ
// @DisplayName: Avoidance deadzone between stopping and backing away from obstacle
// @Description: Distance beyond AVOID_MARGIN parameter, after which vehicle will backaway from obstacles. Increase this parameter if you see vehicle going back and forth in front of obstacle.
// @Units: m
// @Range: 0 2
// @User: Standard
AP_GROUPINFO("BACKUP_DZ", 9, AC_Avoid, _backup_deadzone_m, 0.10f),
// @Param: BACKZ_SPD
// @DisplayName: Avoidance maximum vertical backup speed
// @Description: Maximum speed that will be used to back away from obstacles vertically in height control modes (m/s). Set zero to disable vertical backup.
// @Units: m/s
// @Range: 0 2
// @User: Standard
AP_GROUPINFO("BACKZ_SPD", 10, AC_Avoid, _backup_speed_max_u_ms, 0.75),
#if AP_AVOIDANCE_ALTHOLD_ENABLED
// @Param{Copter}: ANG_MAX
// @DisplayName: Avoidance max lean angle in non-GPS flight modes
// @Description: Max lean angle used to avoid obstacles while in non-GPS modes. Set to zero to disable lean-based avoidance
// @Units: deg
// @Increment: 0.1
// @Range: 0 45
// @User: Standard
AP_GROUPINFO_FRAME("ANG_MAX", 11, AC_Avoid, _angle_max_deg, 10.0, AP_PARAM_FRAME_COPTER | AP_PARAM_FRAME_HELI | AP_PARAM_FRAME_TRICOPTER),
#endif
AP_GROUPEND
};
/// Constructor
AC_Avoid::AC_Avoid()
{
_singleton = this;
AP_Param::setup_object_defaults(this, var_info);
}
// convert parameters
void AC_Avoid::convert_params()
{
#if AP_AVOIDANCE_ALTHOLD_ENABLED
// PARAMETER_CONVERSION - Added: Feb 2026 ahead of ardupilot-4.7
// exit immediately if ANG_MAX has already been configured
if (_angle_max_deg.configured()) {
return;
}
// convert ANGLE_MAX (centi-degrees) to ANG_MAX (degrees)
const AP_Param::ConversionInfo conversion_info[] = {
{ 95, 2, AP_PARAM_INT16, "AVOID_ANG_MAX" }, // AVOID_ANGLE_MAX moved to AVOID_ANG_MAX
};
AP_Param::convert_old_parameters_scaled(conversion_info, ARRAY_SIZE(conversion_info), 0.01, 0);
#endif
}
/*
* This method limits velocity and calculates backaway velocity from various supported fences
* Also limits vertical velocity using adjust_velocity_z method
*/
void AC_Avoid::adjust_velocity_fence(float kP, float accel_cmss, Vector3f &desired_vel_neu_cms, Vector3f &backup_vel_neu_cms, float kP_z, float accel_z_cmss, float dt)
{
// Only horizontal component needed for most fences, since fences are 2D
Vector2f desired_velocity_ne_cms{desired_vel_neu_cms.x, desired_vel_neu_cms.y};
#if AP_FENCE_ENABLED || AP_BEACON_ENABLED
// limit acceleration
const float accel_limited_cmss = MIN(accel_cmss, AC_AVOID_ACCEL_CMSS_MAX);
#endif
// maximum component of desired backup velocity in each quadrant
Vector2f quad_1_back_vel_ne_cms, quad_2_back_vel_ne_cms, quad_3_back_vel_ne_cms, quad_4_back_vel_ne_cms;
#if AP_FENCE_ENABLED
if ((_enabled & AC_AVOID_STOP_AT_FENCE) > 0) {
// Store velocity needed to back away from fence
Vector2f backup_vel_fence_ne_cms;
adjust_velocity_circle_fence(kP, accel_limited_cmss, desired_velocity_ne_cms, backup_vel_fence_ne_cms, dt);
find_max_quadrant_velocity(backup_vel_fence_ne_cms, quad_1_back_vel_ne_cms, quad_2_back_vel_ne_cms, quad_3_back_vel_ne_cms, quad_4_back_vel_ne_cms);
// backup_vel_fence_ne_cms is set to zero after each fence in case the velocity is unset from previous methods
backup_vel_fence_ne_cms.zero();
adjust_velocity_inclusion_and_exclusion_polygons(kP, accel_limited_cmss, desired_velocity_ne_cms, backup_vel_fence_ne_cms, dt);
find_max_quadrant_velocity(backup_vel_fence_ne_cms, quad_1_back_vel_ne_cms, quad_2_back_vel_ne_cms, quad_3_back_vel_ne_cms, quad_4_back_vel_ne_cms);
backup_vel_fence_ne_cms.zero();
adjust_velocity_inclusion_circles(kP, accel_limited_cmss, desired_velocity_ne_cms, backup_vel_fence_ne_cms, dt);
find_max_quadrant_velocity(backup_vel_fence_ne_cms, quad_1_back_vel_ne_cms, quad_2_back_vel_ne_cms, quad_3_back_vel_ne_cms, quad_4_back_vel_ne_cms);
backup_vel_fence_ne_cms.zero();
adjust_velocity_exclusion_circles(kP, accel_limited_cmss, desired_velocity_ne_cms, backup_vel_fence_ne_cms, dt);
find_max_quadrant_velocity(backup_vel_fence_ne_cms, quad_1_back_vel_ne_cms, quad_2_back_vel_ne_cms, quad_3_back_vel_ne_cms, quad_4_back_vel_ne_cms);
}
#endif // AP_FENCE_ENABLED
#if AP_BEACON_ENABLED
if ((_enabled & AC_AVOID_STOP_AT_BEACON_FENCE) > 0) {
// Store velocity needed to back away from beacon fence
Vector2f backup_vel_beacon_ne_cms;
adjust_velocity_beacon_fence(kP, accel_limited_cmss, desired_velocity_ne_cms, backup_vel_beacon_ne_cms, dt);
find_max_quadrant_velocity(backup_vel_beacon_ne_cms, quad_1_back_vel_ne_cms, quad_2_back_vel_ne_cms, quad_3_back_vel_ne_cms, quad_4_back_vel_ne_cms);
}
#endif // AP_BEACON_ENABLED
// check for vertical fence
float desired_velocity_z_cms = desired_vel_neu_cms.z;
float desired_backup_vel_u_cms = 0.0f;
adjust_velocity_z(kP_z, accel_z_cmss, desired_velocity_z_cms, desired_backup_vel_u_cms, dt);
// Desired backup velocity is sum of maximum velocity component in each quadrant
const Vector2f desired_backup_vel_ne_cms = quad_1_back_vel_ne_cms + quad_2_back_vel_ne_cms + quad_3_back_vel_ne_cms + quad_4_back_vel_ne_cms;
backup_vel_neu_cms = Vector3f{desired_backup_vel_ne_cms.x, desired_backup_vel_ne_cms.y, desired_backup_vel_u_cms};
desired_vel_neu_cms = Vector3f{desired_velocity_ne_cms.x, desired_velocity_ne_cms.y, desired_velocity_z_cms};
}
/*
* Adjusts the desired velocity so that the vehicle can stop
* before the fence/object.
* kP, accel_cmss are for the horizontal axis
* kP_z, accel_z_cmss are for vertical axis
*/
void AC_Avoid::adjust_velocity(Vector3f &desired_vel_neu_cms, bool &backing_up, float kP, float accel_cmss, float kP_z, float accel_z_cmss, float dt)
{
// exit immediately if disabled
if (_enabled == AC_AVOID_DISABLED) {
return;
}
// make a copy of input velocity, because desired_vel_neu_cms might be changed
const Vector3f desired_vel_original_neu_cms = desired_vel_neu_cms;
// limit acceleration
const float accel_limited_cmss = MIN(accel_cmss, AC_AVOID_ACCEL_CMSS_MAX);
// maximum component of horizontal desired backup velocity in each quadrant
Vector2f quad_1_back_vel_ne_cms, quad_2_back_vel_ne_cms, quad_3_back_vel_ne_cms, quad_4_back_vel_ne_cms;
float back_vel_up_cms = 0.0f;
float back_vel_down_cms = 0.0f;
// Avoidance in response to proximity sensor
if (proximity_avoidance_enabled() && _proximity_alt_enabled) {
// Store velocity needed to back away from physical obstacles
Vector3f backup_vel_proximity_neu_cms;
adjust_velocity_proximity(kP, accel_limited_cmss, desired_vel_neu_cms, backup_vel_proximity_neu_cms, kP_z,accel_z_cmss, dt);
find_max_quadrant_velocity_3D(backup_vel_proximity_neu_cms, quad_1_back_vel_ne_cms, quad_2_back_vel_ne_cms, quad_3_back_vel_ne_cms, quad_4_back_vel_ne_cms, back_vel_up_cms, back_vel_down_cms);
}
// Avoidance in response to various fences
Vector3f backup_vel_fence_neu_cms;
adjust_velocity_fence(kP, accel_cmss, desired_vel_neu_cms, backup_vel_fence_neu_cms, kP_z, accel_z_cmss, dt);
find_max_quadrant_velocity_3D(backup_vel_fence_neu_cms , quad_1_back_vel_ne_cms, quad_2_back_vel_ne_cms, quad_3_back_vel_ne_cms, quad_4_back_vel_ne_cms, back_vel_up_cms, back_vel_down_cms);
// Desired backup velocity is sum of maximum velocity component in each quadrant
const Vector2f desired_backup_vel_ne_cms = quad_1_back_vel_ne_cms + quad_2_back_vel_ne_cms + quad_3_back_vel_ne_cms + quad_4_back_vel_ne_cms;
const float desired_backup_vel_u_cms = back_vel_down_cms + back_vel_up_cms;
Vector3f desired_backup_vel_neu_cm{desired_backup_vel_ne_cms.x, desired_backup_vel_ne_cms.y, desired_backup_vel_u_cms};
const float backup_speed_max_ne_cms = _backup_speed_max_ne_ms * 100.0;
if (!desired_backup_vel_neu_cm.xy().is_zero() && is_positive(backup_speed_max_ne_cms)) {
backing_up = true;
// Constrain horizontal backing away speed
desired_backup_vel_neu_cm.xy().limit_length(backup_speed_max_ne_cms);
// let user take control if they are backing away at a greater speed than what we have calculated
// this has to be done for x,y,z separately. For eg, user is doing fine in "x" direction but might need backing up in "y".
if (!is_zero(desired_backup_vel_neu_cm.x)) {
if (is_positive(desired_backup_vel_neu_cm.x)) {
desired_vel_neu_cms.x = MAX(desired_vel_neu_cms.x, desired_backup_vel_neu_cm.x);
} else {
desired_vel_neu_cms.x = MIN(desired_vel_neu_cms.x, desired_backup_vel_neu_cm.x);
}
}
if (!is_zero(desired_backup_vel_neu_cm.y)) {
if (is_positive(desired_backup_vel_neu_cm.y)) {
desired_vel_neu_cms.y = MAX(desired_vel_neu_cms.y, desired_backup_vel_neu_cm.y);
} else {
desired_vel_neu_cms.y = MIN(desired_vel_neu_cms.y, desired_backup_vel_neu_cm.y);
}
}
}
const float backup_speed_max_u_cms = _backup_speed_max_u_ms * 100.0;
if (!is_zero(desired_backup_vel_neu_cm.z) && is_positive(backup_speed_max_u_cms)) {
backing_up = true;
// Constrain vertical backing away speed
desired_backup_vel_neu_cm.z = constrain_float(desired_backup_vel_neu_cm.z, -backup_speed_max_u_cms, backup_speed_max_u_cms);
if (!is_zero(desired_backup_vel_neu_cm.z)) {
if (is_positive(desired_backup_vel_neu_cm.z)) {
desired_vel_neu_cms.z = MAX(desired_vel_neu_cms.z, desired_backup_vel_neu_cm.z);
} else {
desired_vel_neu_cms.z = MIN(desired_vel_neu_cms.z, desired_backup_vel_neu_cm.z);
}
}
}
// limit acceleration
limit_accel_NEU_cm(desired_vel_original_neu_cms, desired_vel_neu_cms, dt);
if (desired_vel_original_neu_cms != desired_vel_neu_cms) {
_last_limit_time = AP_HAL::millis();
}
#if HAL_LOGGING_ENABLED
if (limits_active()) {
// log at not more than 10hz (adjust_velocity method can be potentially called at 400hz!)
uint32_t now = AP_HAL::millis();
if ((now - _last_log_ms) > 100) {
_last_log_ms = now;
Write_SimpleAvoidance(true, desired_vel_original_neu_cms, desired_vel_neu_cms, backing_up);
}
} else {
// avoidance isn't active anymore
// log once so that it registers in logs
if (_last_log_ms) {
Write_SimpleAvoidance(false, desired_vel_original_neu_cms, desired_vel_neu_cms, backing_up);
// this makes sure logging won't run again till it is active
_last_log_ms = 0;
}
}
#endif
}
/*
* Limit acceleration so that change of velocity output by avoidance library is controlled
* This helps reduce jerks and sudden movements in the vehicle
*/
void AC_Avoid::limit_accel_NEU_cm(const Vector3f &original_vel_neu_cms, Vector3f &modified_vel_neu_cms, float dt)
{
if (original_vel_neu_cms == modified_vel_neu_cms || is_zero(_accel_max_mss) || !is_positive(dt)) {
// we can't limit accel if any of these conditions are true
return;
}
if (AP_HAL::millis() - _last_limit_time > AC_AVOID_ACCEL_TIMEOUT_MS) {
// reset this velocity because its been a long time since avoidance was active
_prev_avoid_vel_neu_cms = original_vel_neu_cms;
}
// acceleration demanded by avoidance
const Vector3f accel_neu_cmss = (modified_vel_neu_cms - _prev_avoid_vel_neu_cms)/dt;
// max accel in cm
const float accel_max_cmss = _accel_max_mss * 100.0f;
if (accel_neu_cmss.length() > accel_max_cmss) {
// pull back on the acceleration
const Vector3f accel_direction_neu = accel_neu_cmss.normalized();
modified_vel_neu_cms = (accel_direction_neu * accel_max_cmss) * dt + _prev_avoid_vel_neu_cms;
}
_prev_avoid_vel_neu_cms = modified_vel_neu_cms;
return;
}
// This method is used in most Rover modes and not in Copter
// adjust desired horizontal speed so that the vehicle stops before the fence or object
// accel (maximum acceleration/deceleration) is in m/s/s
// heading is in radians
// speed is in m/s
// kP should be zero for linear response, non-zero for non-linear response
void AC_Avoid::adjust_speed(float kP, float accel_mss, float heading_rad, float &speed_ms, float dt)
{
// convert heading and speed into velocity vector
Vector3f vel_neu_cms{
cosf(heading_rad) * speed_ms * 100.0f,
sinf(heading_rad) * speed_ms * 100.0f,
0.0f
};
bool backing_up = false;
adjust_velocity(vel_neu_cms, backing_up, kP, accel_mss * 100.0f, 0, 0, dt);
const Vector2f vel_ne_cms{vel_neu_cms.x, vel_neu_cms.y};
if (backing_up) {
// back up
if (fabsf(wrap_180(degrees(vel_ne_cms.angle())) - degrees(heading_rad)) > 90.0f) {
// Big difference between the direction of velocity vector and actual heading therefore we need to reverse the direction
speed_ms = -vel_ne_cms.length() * 0.01f;
} else {
speed_ms = vel_ne_cms.length() * 0.01f;
}
return;
}
// No need to back up so adjust speed towards zero if needed
if (is_negative(speed_ms)) {
speed_ms = -vel_ne_cms.length() * 0.01f;
} else {
speed_ms = vel_ne_cms.length() * 0.01f;
}
}
// adjust vertical climb rate so vehicle does not break the vertical fence
void AC_Avoid::adjust_velocity_z(float kP, float accel_cmss, float& climb_rate_cms, float dt) {
float backup_speed_cms = 0.0f;
adjust_velocity_z(kP, accel_cmss, climb_rate_cms, backup_speed_cms, dt);
if (!is_zero(backup_speed_cms)) {
if (is_negative(backup_speed_cms)) {
climb_rate_cms = MIN(climb_rate_cms, backup_speed_cms);
} else {
climb_rate_cms = MAX(climb_rate_cms, backup_speed_cms);
}
}
}
// adjust vertical climb rate so vehicle does not break the vertical fence
void AC_Avoid::adjust_velocity_z(float kP, float accel_cmss, float& climb_rate_cms, float& backup_speed_cms, float dt)
{
#ifdef AP_AVOID_ENABLE_Z
// exit immediately if disabled
if (_enabled == AC_AVOID_DISABLED) {
return;
}
// do not adjust climb_rate if level
if (is_zero(climb_rate_cms)) {
return;
}
const AP_AHRS &_ahrs = AP::ahrs();
// limit acceleration
const float accel_limited_cmss = MIN(accel_cmss, AC_AVOID_ACCEL_CMSS_MAX);
bool limit_min_alt = false;
bool limit_max_alt = false;
float max_alt_diff_m = 0.0f; // distance from altitude limit to vehicle in metres (positive means vehicle is below limit)
float min_alt_diff_m = 0.0f;
#if AP_FENCE_ENABLED
// calculate distance below fence
AC_Fence *fence = AP::fence();
if ((_enabled & AC_AVOID_STOP_AT_FENCE) > 0 && fence) {
// calculate distance from vehicle to safe altitude
if ((fence->get_enabled_fences() & AC_FENCE_TYPE_ALT_MIN) > 0) {
float veh_alt_m;
if (fence->get_alt_in_alt_min_frame_m(veh_alt_m)) {
// fence.get_safe_alt_min_m() is UP, veh_alt_m is UP:
min_alt_diff_m = veh_alt_m - fence->get_safe_alt_min_m();
limit_min_alt = true;
}
}
if ((fence->get_enabled_fences() & AC_FENCE_TYPE_ALT_MAX) > 0) {
float veh_alt_m;
if (fence->get_alt_in_alt_max_frame_m(veh_alt_m)) {
// fence.get_safe_alt_max_m() is UP, veh_alt_m is UP:
max_alt_diff_m = fence->get_safe_alt_max_m() - veh_alt_m;
limit_max_alt = true;
}
}
}
#endif
// calculate distance to (e.g.) optical flow altitude limit
// AHRS values are always in metres
float alt_limit_m;
float curr_alt_m;
if (_ahrs.get_hgt_ctrl_limit(alt_limit_m) &&
_ahrs.get_relative_position_D_origin_float(curr_alt_m)) {
// alt_limit_m is UP, curr_alt_m is DOWN:
const float ctrl_alt_diff_m = alt_limit_m + curr_alt_m;
if (!limit_max_alt || ctrl_alt_diff_m < max_alt_diff_m) {
max_alt_diff_m = ctrl_alt_diff_m;
limit_max_alt = true;
}
}
#if HAL_PROXIMITY_ENABLED
// get distance from proximity sensor
float proximity_alt_diff_m;
AP_Proximity *proximity = AP::proximity();
if (proximity && proximity_avoidance_enabled() && proximity->get_upward_distance(proximity_alt_diff_m)) {
proximity_alt_diff_m -= _margin_m;
if (!limit_max_alt || proximity_alt_diff_m < max_alt_diff_m) {
max_alt_diff_m = proximity_alt_diff_m;
limit_max_alt = true;
}
}
#endif
// limit climb rate
if (limit_max_alt || limit_min_alt) {
const float max_back_spd_cms = _backup_speed_max_u_ms * 100.0;
// do not allow climbing if we've breached the safe altitude
if (max_alt_diff_m <= 0.0f && limit_max_alt) {
climb_rate_cms = MIN(climb_rate_cms, 0.0f);
// also calculate backup speed that will get us back to safe altitude
if (is_positive(max_back_spd_cms)) {
backup_speed_cms = -1*(get_max_speed(kP, accel_limited_cmss, -max_alt_diff_m * 100.0f, dt));
// Constrain to max backup speed
backup_speed_cms = MAX(backup_speed_cms, -max_back_spd_cms);
}
return;
// do not allow descending if we've breached the safe altitude
} else if (min_alt_diff_m <= 0.0f && limit_min_alt) {
climb_rate_cms = MAX(climb_rate_cms, 0.0f);
// also calculate backup speed that will get us back to safe altitude
if (is_positive(max_back_spd_cms)) {
backup_speed_cms = get_max_speed(kP, accel_limited_cmss, -min_alt_diff_m * 100.0f, dt);
// Constrain to max backup speed
backup_speed_cms = MIN(backup_speed_cms, max_back_spd_cms);
}
return;
}
// limit climb rate
if (limit_max_alt) {
const float max_alt_max_speed_cms = get_max_speed(kP, accel_limited_cmss, max_alt_diff_m * 100.0f, dt);
climb_rate_cms = MIN(max_alt_max_speed_cms, climb_rate_cms);
}
if (limit_min_alt) {
const float max_alt_min_speed = get_max_speed(kP, accel_limited_cmss, min_alt_diff_m * 100.0f, dt);
climb_rate_cms = MAX(-max_alt_min_speed, climb_rate_cms);
}
}
#endif
}
#if AP_AVOIDANCE_ALTHOLD_ENABLED
// adjust roll-pitch to push vehicle away from objects
// roll and pitch value are in radians
// veh_angle_max_rad is the user defined maximum lean angle for the vehicle in radians
void AC_Avoid::adjust_roll_pitch_rad(float &roll_rad, float &pitch_rad, float veh_angle_max_rad) const
{
// exit immediately if proximity based avoidance is disabled
if (!proximity_avoidance_enabled()) {
return;
}
// exit immediately if angle max is zero
if (_angle_max_deg <= 0.0f || veh_angle_max_rad <= 0.0f) {
return;
}
float roll_positive_norm = 0.0f; // maximum positive roll value
float roll_negative_norm = 0.0f; // minimum negative roll value
float pitch_positive_norm = 0.0f; // maximum positive pitch value
float pitch_negative_norm = 0.0f; // minimum negative pitch value
// get maximum positive and negative roll and pitch percentages from proximity sensor
get_proximity_roll_pitch_norm(roll_positive_norm, roll_negative_norm, pitch_positive_norm, pitch_negative_norm);
// add maximum positive and negative percentages together for roll and pitch, convert to radians
Vector2f rp_out_rad((roll_positive_norm + roll_negative_norm) * radians(45.0), (pitch_positive_norm + pitch_negative_norm) * radians(45.0));
// apply avoidance angular limits
// the object avoidance lean angle is never more than 75% of the total angle-limit to allow the pilot to override
const float angle_limit_rad = constrain_float(radians(_angle_max_deg), 0.0f, veh_angle_max_rad * AC_AVOID_ANGLE_MAX_PERCENT);
float vec_length_rad = rp_out_rad.length();
if (vec_length_rad > angle_limit_rad) {
rp_out_rad *= (angle_limit_rad / vec_length_rad);
}
// add passed in roll, pitch angles
rp_out_rad.x += roll_rad;
rp_out_rad.y += pitch_rad;
// apply total angular limits
vec_length_rad = rp_out_rad.length();
if (vec_length_rad > veh_angle_max_rad) {
rp_out_rad *= (veh_angle_max_rad / vec_length_rad);
}
// return adjusted roll, pitch
roll_rad = rp_out_rad.x;
pitch_rad = rp_out_rad.y;
}
#endif // AP_AVOIDANCE_ALTHOLD_ENABLED
/*
* Note: This method is used to limit velocity horizontally only
* Limits the component of desired_vel in the direction of the unit vector
* limit_direction_ne to be at most the maximum speed permitted by the limit_distance.
*
* The function is unit-agnostic — accel, desired_vel_ne, and limit_direction_ne
* must all use the same base unit (e.g. m, cm) for correct scaling.
*
* Uses velocity adjustment idea from Randy's second email on this thread:
* https://groups.google.com/forum/#!searchin/drones-discuss/obstacle/drones-discuss/QwUXz__WuqY/qo3G8iTLSJAJ
*/
void AC_Avoid::limit_velocity_NE(float kP, float accel, Vector2f &desired_vel_ne, const Vector2f& limit_direction_ne, float limit_distance, float dt) const
{
const float max_speed = get_max_speed(kP, accel, limit_distance, dt);
// project onto limit direction
const float speed = desired_vel_ne * limit_direction_ne;
if (speed > max_speed) {
// subtract difference between desired speed and maximum acceptable speed
desired_vel_ne += limit_direction_ne * (max_speed - speed);
}
}
/*
* Note: This method is used to limit velocity horizontally and vertically given a 3D desired velocity vector
* Limits the component of desired_vel_neu in the direction of the obstacle_vector_neu based on the passed value of "margin"
*
* The function is unit-agnostic — accel, desired_vel_neu, obstacle_vector_neu, margin, and accel_u
* must all use the same base unit (e.g. m, cm) for correct scaling.
*/
void AC_Avoid::limit_velocity_NEU(float kP, float accel, Vector3f &desired_vel_neu, const Vector3f& obstacle_vector_neu, float margin, float kP_z, float accel_u, float dt) const
{
if (desired_vel_neu.is_zero()) {
// nothing to limit
return;
}
// create a margin length vector in the direction of desired_vel_cms
// this will create larger margin towards the direction vehicle is travelling in
const Vector3f margin_vector_neu = desired_vel_neu.normalized() * margin;
const Vector2f limit_direction_ne{obstacle_vector_neu.x, obstacle_vector_neu.y};
if (!limit_direction_ne.is_zero()) {
const float distance_from_fence_xy = MAX((limit_direction_ne.length() - Vector2f{margin_vector_neu.x, margin_vector_neu.y}.length()), 0.0f);
Vector2f velocity_ne{desired_vel_neu.x, desired_vel_neu.y};
limit_velocity_NE(kP, accel, velocity_ne, limit_direction_ne.normalized(), distance_from_fence_xy, dt);
desired_vel_neu.x = velocity_ne.x;
desired_vel_neu.y = velocity_ne.y;
}
if (is_zero(desired_vel_neu.z) || is_zero(obstacle_vector_neu.z)) {
// nothing to limit vertically if desired_vel_cms.z is zero
// if obstacle_vector_neu.z is zero then the obstacle is probably horizontally located, and we can move vertically
return;
}
if (is_positive(desired_vel_neu.z) != is_positive(obstacle_vector_neu.z)) {
// why limit velocity vertically when we are going the opposite direction
return;
}
// to check if Z velocity changes
const float velocity_original_u = desired_vel_neu.z;
const float speed_u = fabsf(desired_vel_neu.z);
// obstacle_vector_neu.z and margin_vector_neu.z should be in same direction as checked above
const float dist_u = MAX(fabsf(obstacle_vector_neu.z) - fabsf(margin_vector_neu.z), 0.0f);
if (is_zero(dist_u)) {
// eliminate any vertical velocity
desired_vel_neu.z = 0.0f;
} else {
const float max_z_speed = get_max_speed(kP_z, accel_u, dist_u, dt);
desired_vel_neu.z = MIN(max_z_speed, speed_u);
}
// make sure the direction of the Z velocity did not change
// we are only limiting speed here, not changing directions
// check if original z velocity is positive or negative
if (is_negative(velocity_original_u)) {
desired_vel_neu.z = desired_vel_neu.z * -1.0f;
}
}
/*
* Compute the back away horizontal velocity required to avoid breaching margin
* INPUT: This method requires the breach in margin distance (back_distance_cm), direction towards the breach (limit_direction)
* It then calculates the desired backup velocity and passes it on to "find_max_quadrant_velocity" method to distribute the velocity vectors into respective quadrants
* OUTPUT: The method then outputs four velocities (quad1/2/3/4_back_vel_cms), which correspond to the maximum horizontal desired backup velocity in each quadrant
*/
void AC_Avoid::calc_backup_velocity_2D(float kP, float accel_cmss, Vector2f &quad1_back_vel_cms, Vector2f &quad2_back_vel_cms, Vector2f &quad3_back_vel_cms, Vector2f &quad4_back_vel_cms, float back_distance_cm, Vector2f limit_direction, float dt) const
{
if (limit_direction.is_zero()) {
// protect against divide by zero
return;
}
// speed required to move away the exact distance that we have breached the margin with
const float back_speed_cms = get_max_speed(kP, 0.4f * accel_cmss, fabsf(back_distance_cm), dt);
// direction to the obstacle
limit_direction.normalize();
// move in the opposite direction with the required speed
Vector2f back_direction_vel_cms = limit_direction * (-back_speed_cms);
// divide the vector into quadrants, find maximum velocity component in each quadrant
find_max_quadrant_velocity(back_direction_vel_cms, quad1_back_vel_cms, quad2_back_vel_cms, quad3_back_vel_cms, quad4_back_vel_cms);
}
/*
* Compute the back away velocity required to avoid breaching margin, including vertical component
* min_z_vel is <= 0, and stores the greatest velocity in the downwards direction
* max_z_vel is >= 0, and stores the greatest velocity in the upwards direction
* eventually max_z_vel + min_z_vel will give the final desired Z backaway velocity
*/
void AC_Avoid::calc_backup_velocity_3D(float kP, float accel_cmss, Vector2f &quad1_back_vel_cms, Vector2f &quad2_back_vel_cms, Vector2f &quad3_back_vel_cms, Vector2f &quad4_back_vel_cms,
float back_distance_cms, Vector3f limit_direction_neu, float kp_z, float accel_z_cmss, float back_distance_u_cm, float& min_vel_u_cms, float& max_vel_u_cms, float dt) const
{
// backup horizontally
if (is_positive(back_distance_cms)) {
Vector2f limit_direction_ne{limit_direction_neu.x, limit_direction_neu.y};
calc_backup_velocity_2D(kP, accel_cmss, quad1_back_vel_cms, quad2_back_vel_cms, quad3_back_vel_cms, quad4_back_vel_cms, back_distance_cms, limit_direction_ne, dt);
}
// backup vertically
if (!is_zero(back_distance_u_cm)) {
float back_speed_z_cms = get_max_speed(kp_z, 0.4f * accel_z_cmss, fabsf(back_distance_u_cm), dt);
// Down is positive
if (is_positive(back_distance_u_cm)) {
back_speed_z_cms *= -1.0f;
}
// store the z backup speed into min or max z if possible
if (back_speed_z_cms < min_vel_u_cms) {
min_vel_u_cms = back_speed_z_cms;
}
if (back_speed_z_cms > max_vel_u_cms) {
max_vel_u_cms = back_speed_z_cms;
}
}
}
/*
* Calculate maximum velocity vector that can be formed in each quadrant
* This method takes the desired backup velocity, and four other velocities corresponding to each quadrant
* The desired velocity is then fit into one of the 4 quadrant velocities as per the sign of its components
* This ensures that if we have multiple backup velocities, we can get the maximum of all of those velocities in each quadrant
*/
void AC_Avoid::find_max_quadrant_velocity(Vector2f &desired_vel, Vector2f &quad1_vel, Vector2f &quad2_vel, Vector2f &quad3_vel, Vector2f &quad4_vel) const
{
if (desired_vel.is_zero()) {
return;
}
// first quadrant: +ve x, +ve y direction
if (is_positive(desired_vel.x) && is_positive(desired_vel.y)) {
quad1_vel = Vector2f{MAX(quad1_vel.x, desired_vel.x), MAX(quad1_vel.y,desired_vel.y)};
}
// second quadrant: -ve x, +ve y direction
if (is_negative(desired_vel.x) && is_positive(desired_vel.y)) {
quad2_vel = Vector2f{MIN(quad2_vel.x, desired_vel.x), MAX(quad2_vel.y,desired_vel.y)};
}
// third quadrant: -ve x, -ve y direction
if (is_negative(desired_vel.x) && is_negative(desired_vel.y)) {
quad3_vel = Vector2f{MIN(quad3_vel.x, desired_vel.x), MIN(quad3_vel.y,desired_vel.y)};
}
// fourth quadrant: +ve x, -ve y direction
if (is_positive(desired_vel.x) && is_negative(desired_vel.y)) {
quad4_vel = Vector2f{MAX(quad4_vel.x, desired_vel.x), MIN(quad4_vel.y,desired_vel.y)};
}
}
/*
Calculate maximum velocity vector that can be formed in each quadrant and separately store max & min of vertical components
*/
void AC_Avoid::find_max_quadrant_velocity_3D(Vector3f &desired_vel, Vector2f &quad1_vel, Vector2f &quad2_vel, Vector2f &quad3_vel, Vector2f &quad4_vel, float &max_z_vel, float &min_z_vel) const
{
// split into horizontal and vertical components
Vector2f velocity_ne{desired_vel.x, desired_vel.y};
find_max_quadrant_velocity(velocity_ne, quad1_vel, quad2_vel, quad3_vel, quad4_vel);
// store maximum and minimum of z
if (is_positive(desired_vel.z) && (desired_vel.z > max_z_vel)) {
max_z_vel = desired_vel.z;
}
if (is_negative(desired_vel.z) && (desired_vel.z < min_z_vel)) {
min_z_vel = desired_vel.z;
}
}
/*
* Computes the speed such that the stopping distance
* of the vehicle will be exactly the input distance.
*/
float AC_Avoid::get_max_speed(float kP, float accel, float distance, float dt) const
{
if (is_zero(kP)) {
return safe_sqrt(2.0f * distance * accel);
} else {
return sqrt_controller(distance, kP, accel, dt);
}
}
#if AP_FENCE_ENABLED
/*
* Adjusts the desired velocity for the circular fence.
*/
void AC_Avoid::adjust_velocity_circle_fence(float kP, float accel_cmss, Vector2f &desired_vel_ne_cms, Vector2f &backup_vel_ne_cms, float dt)
{
AC_Fence *fence = AP::fence();
if (fence == nullptr) {
return;
}
AC_Fence &_fence = *fence;
// exit if circular fence is not enabled
if ((_fence.get_enabled_fences() & AC_FENCE_TYPE_CIRCLE) == 0) {
return;
}
// exit if the circular fence has already been breached
if ((_fence.get_breaches() & AC_FENCE_TYPE_CIRCLE) != 0) {
return;
}
// get desired speed
const float desired_speed_cms = desired_vel_ne_cms.length();
if (is_zero(desired_speed_cms)) {
// no avoidance necessary when desired speed is zero
return;
}
const AP_AHRS &_ahrs = AP::ahrs();
// get position as a 2D offset from ahrs home
Vector2f position_ne_cm;
if (!_ahrs.get_relative_position_NE_home(position_ne_cm)) {
// we have no idea where we are....
return;
}
position_ne_cm *= 100.0f; // m -> cm
// get the fence radius in cm
const float fence_radius_cm = _fence.get_radius_m() * 100.0f;
// get the margin to the fence in cm
const float margin_cm = _fence.get_margin_ne_m() * 100.0f;
if (margin_cm > fence_radius_cm) {
return;
}
// get vehicle distance from home
const float dist_from_home_cm = position_ne_cm.length();
if (dist_from_home_cm > fence_radius_cm) {
// outside of circular fence, no velocity adjustments
return;
}
const float distance_to_boundary_cm = fence_radius_cm - dist_from_home_cm;
// for backing away
Vector2f quad_1_back_vel_ne_cms, quad_2_back_vel_ne_cms, quad_3_back_vel_ne_cms, quad_4_back_vel_ne_cms;
// back away if vehicle has breached margin
if (is_negative(distance_to_boundary_cm - margin_cm)) {
calc_backup_velocity_2D(kP, accel_cmss, quad_1_back_vel_ne_cms, quad_2_back_vel_ne_cms, quad_3_back_vel_ne_cms, quad_4_back_vel_ne_cms, margin_cm - distance_to_boundary_cm, position_ne_cm, dt);
}
// desired backup velocity is sum of maximum velocity component in each quadrant
backup_vel_ne_cms = quad_1_back_vel_ne_cms + quad_2_back_vel_ne_cms + quad_3_back_vel_ne_cms + quad_4_back_vel_ne_cms;
// vehicle is inside the circular fence
switch (_behavior) {
case BEHAVIOR_SLIDE: {
// implement sliding behaviour
const Vector2f stopping_point_ne_cm = position_ne_cm + desired_vel_ne_cms * (get_stopping_distance(kP, accel_cmss, desired_speed_cms) / desired_speed_cms);
const float stopping_point_dist_from_home_ne_cm = stopping_point_ne_cm.length();
if (stopping_point_dist_from_home_ne_cm <= fence_radius_cm - margin_cm) {
// stopping before before fence so no need to adjust
return;
}
// unsafe desired velocity - will not be able to stop before reaching margin from fence
// Project stopping point radially onto fence boundary
// Adjusted velocity will point towards this projected point at a safe speed
const Vector2f target_offset_ne_cm = stopping_point_ne_cm * ((fence_radius_cm - margin_cm) / stopping_point_dist_from_home_ne_cm);
const Vector2f target_direction_ne_cm = target_offset_ne_cm - position_ne_cm;
const float distance_to_target_cm = target_direction_ne_cm.length();
if (is_positive(distance_to_target_cm)) {
const float max_speed_cms = get_max_speed(kP, accel_cmss, distance_to_target_cm, dt);
desired_vel_ne_cms = target_direction_ne_cm * (MIN(desired_speed_cms,max_speed_cms) / distance_to_target_cm);
}
break;
}
case (BEHAVIOR_STOP): {
// implement stopping behaviour
// calculate stopping point plus a margin so we look forward far enough to intersect with circular fence
const Vector2f stopping_point_plus_margin_ne_cm = position_ne_cm + desired_vel_ne_cms*((2.0f + margin_cm + get_stopping_distance(kP, accel_cmss, desired_speed_cms))/desired_speed_cms);
const float stopping_point_plus_margin_dist_from_home_cm = stopping_point_plus_margin_ne_cm.length();
if (dist_from_home_cm >= fence_radius_cm - margin_cm) {
// vehicle has already breached margin around fence
// if stopping point is even further from home (i.e. in wrong direction) then adjust speed to zero
// otherwise user is backing away from fence so do not apply limits
if (stopping_point_plus_margin_dist_from_home_cm >= dist_from_home_cm) {
desired_vel_ne_cms.zero();
}
} else {
// shorten vector without adjusting its direction
Vector2f intersection_ne_cm;
if (Vector2f::circle_segment_intersection(position_ne_cm, stopping_point_plus_margin_ne_cm, Vector2f(0.0f,0.0f), fence_radius_cm - margin_cm, intersection_ne_cm)) {
const float distance_to_target_cm = (intersection_ne_cm - position_ne_cm).length();
const float max_speed_cms = get_max_speed(kP, accel_cmss, distance_to_target_cm, dt);
if (max_speed_cms < desired_speed_cms) {
desired_vel_ne_cms *= MAX(max_speed_cms, 0.0f) / desired_speed_cms;
}
}
}
break;
}
}
}
/*
* Adjusts the desired velocity for the exclusion polygons
*/
void AC_Avoid::adjust_velocity_inclusion_and_exclusion_polygons(float kP, float accel_cmss, Vector2f &desired_vel_ne_cms, Vector2f &backup_vel_ne_cms, float dt)
{
const AC_Fence *fence = AP::fence();
if (fence == nullptr) {
return;
}
// exit if polygon fences are not enabled
if ((fence->get_enabled_fences() & AC_FENCE_TYPE_POLYGON) == 0) {
return;
}
// for backing away
Vector2f quad_1_back_vel_ne_cms, quad_2_back_vel_ne_cms, quad_3_back_vel_ne_cms, quad_4_back_vel_ne_cms;
// iterate through inclusion polygons
const uint8_t num_inclusion_polygons = fence->polyfence().get_inclusion_polygon_count();
for (uint8_t i = 0; i < num_inclusion_polygons; i++) {
uint16_t num_points;
const Vector2f* boundary = fence->polyfence().get_inclusion_polygon(i, num_points);
Vector2f backup_vel_inc_ne_cms;
// adjust velocity
adjust_velocity_polygon(kP, accel_cmss, desired_vel_ne_cms, backup_vel_inc_ne_cms, boundary, num_points, fence->get_margin_ne_m(), dt, true);
find_max_quadrant_velocity(backup_vel_inc_ne_cms, quad_1_back_vel_ne_cms, quad_2_back_vel_ne_cms, quad_3_back_vel_ne_cms, quad_4_back_vel_ne_cms);
}
// iterate through exclusion polygons
const uint8_t num_exclusion_polygons = fence->polyfence().get_exclusion_polygon_count();
for (uint8_t i = 0; i < num_exclusion_polygons; i++) {
uint16_t num_points;
const Vector2f* boundary = fence->polyfence().get_exclusion_polygon(i, num_points);
Vector2f backup_vel_exc_ne_cms;
// adjust velocity
adjust_velocity_polygon(kP, accel_cmss, desired_vel_ne_cms, backup_vel_exc_ne_cms, boundary, num_points, fence->get_margin_ne_m(), dt, false);
find_max_quadrant_velocity(backup_vel_exc_ne_cms, quad_1_back_vel_ne_cms, quad_2_back_vel_ne_cms, quad_3_back_vel_ne_cms, quad_4_back_vel_ne_cms);
}
// desired backup velocity is sum of maximum velocity component in each quadrant
backup_vel_ne_cms = quad_1_back_vel_ne_cms + quad_2_back_vel_ne_cms + quad_3_back_vel_ne_cms + quad_4_back_vel_ne_cms;
}
/*
* Adjusts the desired velocity for the inclusion circles
*/
void AC_Avoid::adjust_velocity_inclusion_circles(float kP, float accel_cmss, Vector2f &desired_vel_ne_cms, Vector2f &backup_vel_ne_cms, float dt)
{
const AC_Fence *fence = AP::fence();
if (fence == nullptr) {
return;
}
// return immediately if no inclusion circles
const uint8_t num_circles = fence->polyfence().get_inclusion_circle_count();
if (num_circles == 0) {
return;
}
// exit if polygon fences are not enabled
if ((fence->get_enabled_fences() & AC_FENCE_TYPE_POLYGON) == 0) {
return;
}
// get vehicle position
Vector2f position_ne_cm;
if (!AP::ahrs().get_relative_position_NE_origin_float(position_ne_cm)) {
// do not limit velocity if we don't have a position estimate
return;
}
position_ne_cm = position_ne_cm * 100.0f; // m to cm
// get the margin to the fence in cm
const float margin_cm = fence->get_margin_ne_m() * 100.0f;
// get desired speed
const float desired_speed_cms = desired_vel_ne_cms.length();
// get stopping distance as an offset from the vehicle
Vector2f stopping_offset_ne_cm;
if (!is_zero(desired_speed_cms)) {
switch (_behavior) {
case BEHAVIOR_SLIDE:
stopping_offset_ne_cm = desired_vel_ne_cms * (get_stopping_distance(kP, accel_cmss, desired_speed_cms) / desired_speed_cms);
break;
case BEHAVIOR_STOP:
// calculate stopping point plus a margin so we look forward far enough to intersect with circular fence
stopping_offset_ne_cm = desired_vel_ne_cms * ((2.0f + margin_cm + get_stopping_distance(kP, accel_cmss, desired_speed_cms)) / desired_speed_cms);
break;
}
}
// for backing away
Vector2f quad_1_back_vel_ne_cms, quad_2_back_vel_ne_cms, quad_3_back_vel_ne_cms, quad_4_back_vel_ne_cms;
// iterate through inclusion circles
for (uint8_t i = 0; i < num_circles; i++) {
Vector2f center_pos_ne_cm;
float radius_m;
if (fence->polyfence().get_inclusion_circle(i, center_pos_ne_cm, radius_m)) {
// get position relative to circle's center
const Vector2f position_rel_ne_cm = (position_ne_cm - center_pos_ne_cm);
// if we are outside this circle do not limit velocity for this circle
const float dist_sq_cm = position_rel_ne_cm.length_squared();
const float radius_cm = (radius_m * 100.0f);
if (dist_sq_cm > sq(radius_cm)) {
continue;
}
const float radius_with_margin_cm = radius_cm - margin_cm;
if (is_negative(radius_with_margin_cm)) {
return;
}
const float margin_breach_cm = radius_with_margin_cm - safe_sqrt(dist_sq_cm);
// back away if vehicle has breached margin
if (is_negative(margin_breach_cm)) {
calc_backup_velocity_2D(kP, accel_cmss, quad_1_back_vel_ne_cms, quad_2_back_vel_ne_cms, quad_3_back_vel_ne_cms, quad_4_back_vel_ne_cms, margin_breach_cm, position_rel_ne_cm, dt);
}
if (is_zero(desired_speed_cms)) {
// no avoidance necessary when desired speed is zero
continue;
}
switch (_behavior) {
case BEHAVIOR_SLIDE: {
// implement sliding behaviour
const Vector2f stopping_point_ne_cm = position_rel_ne_cm + stopping_offset_ne_cm;
const float stopping_point_dist_cm = stopping_point_ne_cm.length();
if (is_zero(stopping_point_dist_cm) || (stopping_point_dist_cm <= (radius_cm - margin_cm))) {
// stopping before before fence so no need to adjust for this circle
continue;
}
// unsafe desired velocity - will not be able to stop before reaching margin from fence
// project stopping point radially onto fence boundary
// adjusted velocity will point towards this projected point at a safe speed
const Vector2f target_offset_ne_cm = stopping_point_ne_cm * ((radius_cm - margin_cm) / stopping_point_dist_cm);
const Vector2f target_direction_ne_cm = target_offset_ne_cm - position_rel_ne_cm;
const float distance_to_target_cm = target_direction_ne_cm.length();
if (is_positive(distance_to_target_cm)) {
const float max_speed_cms = get_max_speed(kP, accel_cmss, distance_to_target_cm, dt);
desired_vel_ne_cms = target_direction_ne_cm * (MIN(desired_speed_cms, max_speed_cms) / distance_to_target_cm);
}
}
break;
case BEHAVIOR_STOP: {
// implement stopping behaviour
const Vector2f stopping_point_plus_margin_ne_cm = position_rel_ne_cm + stopping_offset_ne_cm;
const float dist_cm = safe_sqrt(dist_sq_cm);
if (dist_cm >= radius_cm - margin_cm) {
// vehicle has already breached margin around fence
// if stopping point is even further from center (i.e. in wrong direction) then adjust speed to zero
// otherwise user is backing away from fence so do not apply limits
if (stopping_point_plus_margin_ne_cm.length() >= dist_cm) {
desired_vel_ne_cms.zero();
// desired backup velocity is sum of maximum velocity component in each quadrant
backup_vel_ne_cms = quad_1_back_vel_ne_cms + quad_2_back_vel_ne_cms + quad_3_back_vel_ne_cms + quad_4_back_vel_ne_cms;
return;
}
} else {
// shorten vector without adjusting its direction
Vector2f intersection_ne_cm;
if (Vector2f::circle_segment_intersection(position_rel_ne_cm, stopping_point_plus_margin_ne_cm, Vector2f(0.0f,0.0f), radius_cm - margin_cm, intersection_ne_cm)) {
const float distance_to_target_cm = (intersection_ne_cm - position_rel_ne_cm).length();
const float max_speed_cms = get_max_speed(kP, accel_cmss, distance_to_target_cm, dt);
if (max_speed_cms < desired_speed_cms) {
desired_vel_ne_cms *= MAX(max_speed_cms, 0.0f) / desired_speed_cms;
}
}
}
}
break;
}
}
}
// desired backup velocity is sum of maximum velocity component in each quadrant
backup_vel_ne_cms = quad_1_back_vel_ne_cms + quad_2_back_vel_ne_cms + quad_3_back_vel_ne_cms + quad_4_back_vel_ne_cms;
}
/*
* Adjusts the desired velocity for the exclusion circles
*/
void AC_Avoid::adjust_velocity_exclusion_circles(float kP, float accel_cmss, Vector2f &desired_vel_ne_cms, Vector2f &backup_vel_ne_cms, float dt)
{
const AC_Fence *fence = AP::fence();
if (fence == nullptr) {
return;
}
// return immediately if no inclusion circles
const uint8_t num_circles = fence->polyfence().get_exclusion_circle_count();
if (num_circles == 0) {
return;
}
// exit if polygon fences are not enabled
if ((fence->get_enabled_fences() & AC_FENCE_TYPE_POLYGON) == 0) {
return;
}
// get vehicle position
Vector2f position_ne_cm;
if (!AP::ahrs().get_relative_position_NE_origin_float(position_ne_cm)) {
// do not limit velocity if we don't have a position estimate
return;
}
position_ne_cm = position_ne_cm * 100.0f; // m to cm
// get the margin to the fence in cm
const float margin_cm = fence->get_margin_ne_m() * 100.0f;
// for backing away
Vector2f quad_1_back_vel_ne_cms, quad_2_back_vel_ne_cms, quad_3_back_vel_ne_cms, quad_4_back_vel_ne_cms;
// get desired speed
const float desired_speed_cms = desired_vel_ne_cms.length();
// calculate stopping distance as an offset from the vehicle (only used for BEHAVIOR_STOP)
// add a margin so we look forward far enough to intersect with circular fence
Vector2f stopping_offset_ne_cm;
if (!is_zero(desired_speed_cms)) {
if ((AC_Avoid::BehaviourType)_behavior.get() == BEHAVIOR_STOP) {
stopping_offset_ne_cm = desired_vel_ne_cms * ((2.0f + margin_cm + get_stopping_distance(kP, accel_cmss, desired_speed_cms)) / desired_speed_cms);
}
}
// iterate through exclusion circles
for (uint8_t i = 0; i < num_circles; i++) {
Vector2f center_pos_ne_cm;
float radius_m;
if (fence->polyfence().get_exclusion_circle(i, center_pos_ne_cm, radius_m)) {
// get position relative to circle's center
const Vector2f position_rel_ne_cm = (position_ne_cm - center_pos_ne_cm);
// if we are inside this circle do not limit velocity for this circle
const float dist_sq_cm = position_rel_ne_cm.length_squared();
const float radius_cm = (radius_m * 100.0f);
if (radius_cm < margin_cm) {
return;
}
if (dist_sq_cm < sq(radius_cm)) {
continue;
}
const Vector2f vector_to_center_ne_cm = center_pos_ne_cm - position_ne_cm;
const float dist_to_boundary_cm = vector_to_center_ne_cm.length() - radius_cm;
// back away if vehicle has breached margin
if (is_negative(dist_to_boundary_cm - margin_cm)) {
calc_backup_velocity_2D(kP, accel_cmss, quad_1_back_vel_ne_cms, quad_2_back_vel_ne_cms, quad_3_back_vel_ne_cms, quad_4_back_vel_ne_cms, margin_cm - dist_to_boundary_cm, vector_to_center_ne_cm, dt);
}
if (is_zero(desired_speed_cms)) {
// no avoidance necessary when desired speed is zero
continue;
}
switch (_behavior) {
case BEHAVIOR_SLIDE: {
// vector from current position to circle's center
Vector2f limit_direction_ne_cm = vector_to_center_ne_cm;
if (limit_direction_ne_cm.is_zero()) {
// vehicle is exactly on circle center so do not limit velocity
continue;
}
// calculate distance to edge of circle
const float limit_distance_cm = limit_direction_ne_cm.length() - radius_cm;
if (!is_positive(limit_distance_cm)) {
// vehicle is within circle so do not limit velocity
continue;
}
// vehicle is outside the circle, adjust velocity to stay outside
limit_direction_ne_cm.normalize();
limit_velocity_NE(kP, accel_cmss, desired_vel_ne_cms, limit_direction_ne_cm, MAX(limit_distance_cm - margin_cm, 0.0f), dt);
}
break;
case BEHAVIOR_STOP: {
// implement stopping behaviour
const Vector2f stopping_point_plus_margin_ne_cm = position_rel_ne_cm + stopping_offset_ne_cm;
const float dist_cm = safe_sqrt(dist_sq_cm);
if (dist_cm < radius_cm + margin_cm) {
// vehicle has already breached margin around fence
// if stopping point is closer to center (i.e. in wrong direction) then adjust speed to zero
// otherwise user is backing away from fence so do not apply limits
if (stopping_point_plus_margin_ne_cm.length() <= dist_cm) {
desired_vel_ne_cms.zero();
backup_vel_ne_cms = quad_1_back_vel_ne_cms + quad_2_back_vel_ne_cms + quad_3_back_vel_ne_cms + quad_4_back_vel_ne_cms;
return;
}
} else {
// shorten vector without adjusting its direction
Vector2f intersection_ne_cm;
if (Vector2f::circle_segment_intersection(position_rel_ne_cm, stopping_point_plus_margin_ne_cm, Vector2f(0.0f,0.0f), radius_cm + margin_cm, intersection_ne_cm)) {
const float distance_to_target_cm = (intersection_ne_cm - position_rel_ne_cm).length();
const float max_speed_cms = get_max_speed(kP, accel_cmss, distance_to_target_cm, dt);
if (max_speed_cms < desired_speed_cms) {
desired_vel_ne_cms *= MAX(max_speed_cms, 0.0f) / desired_speed_cms;
}
}
}
}
break;
}
}
}
// desired backup velocity is sum of maximum velocity component in each quadrant
backup_vel_ne_cms = quad_1_back_vel_ne_cms + quad_2_back_vel_ne_cms + quad_3_back_vel_ne_cms + quad_4_back_vel_ne_cms;
}
#endif // AP_FENCE_ENABLED
#if AP_BEACON_ENABLED
/*
* Adjusts the desired velocity for the beacon fence.
*/
void AC_Avoid::adjust_velocity_beacon_fence(float kP, float accel_cmss, Vector2f &desired_vel_ne_cms, Vector2f &backup_vel_ne_cms, float dt)
{
AP_Beacon *_beacon = AP::beacon();
// exit if the beacon is not present
if (_beacon == nullptr) {
return;
}
// get boundary from beacons
uint16_t num_points = 0;
const Vector2f* boundary = _beacon->get_boundary_points(num_points);
if ((boundary == nullptr) || (num_points == 0)) {
return;
}
// adjust velocity using beacon
float margin_m = 0;
#if AP_FENCE_ENABLED
if (AP::fence()) {
margin_m = AP::fence()->get_margin_ne_m();
}
#endif
adjust_velocity_polygon(kP, accel_cmss, desired_vel_ne_cms, backup_vel_ne_cms, boundary, num_points, margin_m, dt, true);
}
#endif // AP_BEACON_ENABLED
/*
* Adjusts the desired velocity based on output from the proximity sensor
*/
void AC_Avoid::adjust_velocity_proximity(float kP, float accel_cmss, Vector3f &desired_vel_neu_cms, Vector3f &backup_vel_neu_cms, float kP_z, float accel_u_cmss, float dt)
{
#if HAL_PROXIMITY_ENABLED
// exit immediately if proximity sensor is not present
AP_Proximity *proximity = AP::proximity();
if (!proximity) {
return;
}
AP_Proximity &_proximity = *proximity;
// get total number of obstacles
const uint8_t obstacle_num = _proximity.get_obstacle_count();
if (obstacle_num == 0) {
// no obstacles
return;
}
const AP_AHRS &_ahrs = AP::ahrs();
// for backing away
Vector2f quad_1_back_vel_ne_cms, quad_2_back_vel_ne_cms, quad_3_back_vel_ne_cms, quad_4_back_vel_ne_cms;
float max_back_vel_u_cms = 0.0f;
float min_back_vel_u_cms = 0.0f;
// rotate velocity vector from earth frame to body-frame since obstacles are in body-frame
const Vector2f desired_vel_body_ne_cms = _ahrs.earth_to_body2D(Vector2f{desired_vel_neu_cms.x, desired_vel_neu_cms.y});
// safe_vel_ne_cms will be adjusted to stay away from Proximity Obstacles
Vector3f safe_vel_neu_cms = Vector3f{desired_vel_body_ne_cms.x, desired_vel_body_ne_cms.y, desired_vel_neu_cms.z};
const Vector3f safe_vel_orig_neu_cms = safe_vel_neu_cms;
// calc margin in cm
const float margin_cm = MAX(_margin_m * 100.0f, 0.0f);
Vector3f stopping_point_plus_margin_neu_cm;
if (!desired_vel_neu_cms.is_zero()) {
// only used for "stop mode". Pre-calculating the stopping point here makes sure we do not need to repeat the calculations under iterations.
const float speed_cms = safe_vel_neu_cms.length();
stopping_point_plus_margin_neu_cm = safe_vel_neu_cms * ((2.0f + margin_cm + get_stopping_distance(kP, accel_cmss, speed_cms)) / speed_cms);
}
for (uint8_t i = 0; i deadzone_cm) {
// this vector will help us decide how much we have to back away horizontally and vertically
const Vector3f margin_vector_neu_cm = vector_to_obstacle_neu.normalized() * breach_dist_cm;
const float xy_back_dist = margin_vector_neu_cm.xy().length();
const float z_back_dist = margin_vector_neu_cm.z;
calc_backup_velocity_3D(kP, accel_cmss, quad_1_back_vel_ne_cms, quad_2_back_vel_ne_cms, quad_3_back_vel_ne_cms, quad_4_back_vel_ne_cms, xy_back_dist, vector_to_obstacle_neu, kP_z, accel_u_cmss, z_back_dist, min_back_vel_u_cms, max_back_vel_u_cms, dt);
}
}
if (desired_vel_neu_cms.is_zero()) {
// cannot limit velocity if there is nothing to limit
// backing up (if needed) has already been done
continue;
}
switch (_behavior) {
case BEHAVIOR_SLIDE: {
Vector3f limit_direction_neu{vector_to_obstacle_neu};
// distance to closest point
const float limit_distance_cm = limit_direction_neu.length();
if (is_zero(limit_distance_cm)) {
// We are exactly on the edge, this should ideally never be possible
// i.e. do not adjust velocity.
continue;
}
// Adjust velocity to not violate margin.
limit_velocity_NEU(kP, accel_cmss, safe_vel_neu_cms, limit_direction_neu, margin_cm, kP_z, accel_u_cmss, dt);
break;
}
case BEHAVIOR_STOP: {
// vector from current position to obstacle
Vector3f limit_direction_neu;
// find closest point with line segment
// also see if the vehicle will "roughly" intersect the boundary with the projected stopping point
const bool intersect = _proximity.closest_point_from_segment_to_obstacle(i, Vector3f{}, stopping_point_plus_margin_neu_cm, limit_direction_neu);
if (intersect) {
// the vehicle is intersecting the plane formed by the boundary
// distance to the closest point from the stopping point
float limit_distance_cm = limit_direction_neu.length();
if (is_zero(limit_distance_cm)) {
// We are exactly on the edge, this should ideally never be possible
// i.e. do not adjust velocity.
return;
}
if (limit_distance_cm <= margin_cm) {
// we are within the margin so stop vehicle
safe_vel_neu_cms.zero();
} else {
// vehicle inside the given edge, adjust velocity to not violate this edge
limit_velocity_NEU(kP, accel_cmss, safe_vel_neu_cms, limit_direction_neu, margin_cm, kP_z, accel_u_cmss, dt);
}
break;
}
}
}
}
// desired backup velocity is sum of maximum velocity component in each quadrant
const Vector2f desired_back_vel_cms_xy = quad_1_back_vel_ne_cms + quad_2_back_vel_ne_cms + quad_3_back_vel_ne_cms + quad_4_back_vel_ne_cms;
const float desired_back_vel_cms_z = max_back_vel_u_cms + min_back_vel_u_cms;
if (safe_vel_neu_cms == safe_vel_orig_neu_cms && desired_back_vel_cms_xy.is_zero() && is_zero(desired_back_vel_cms_z)) {
// proximity avoidance did nothing, no point in doing the calculations below. Return early
backup_vel_neu_cms.zero();
return;
}
// set modified desired velocity vector and back away velocity vector
// vectors were in body-frame, rotate resulting vector back to earth-frame
const Vector2f safe_vel_ne_cms = _ahrs.body_to_earth2D(Vector2f{safe_vel_neu_cms.x, safe_vel_neu_cms.y});
desired_vel_neu_cms = Vector3f{safe_vel_ne_cms.x, safe_vel_ne_cms.y, safe_vel_neu_cms.z};
const Vector2f backup_vel_ne_cms = _ahrs.body_to_earth2D(desired_back_vel_cms_xy);
backup_vel_neu_cms = Vector3f{backup_vel_ne_cms.x, backup_vel_ne_cms.y, desired_back_vel_cms_z};
#endif // HAL_PROXIMITY_ENABLED
}
/*
* Adjusts the desired velocity for the polygon fence.
*/
void AC_Avoid::adjust_velocity_polygon(float kP, float accel_cmss, Vector2f &desired_vel_cms, Vector2f &backup_vel_ne_cms, const Vector2f* boundary, uint16_t num_points, float margin, float dt, bool stay_inside)
{
// exit if there are no points
if (boundary == nullptr || num_points == 0) {
return;
}
const AP_AHRS &_ahrs = AP::ahrs();
// do not adjust velocity if vehicle is outside the polygon fence
Vector2f position_ne_cm;
if (!_ahrs.get_relative_position_NE_origin_float(position_ne_cm)) {
// boundary is in earth frame but we have no idea
// where we are
return;
}
position_ne_cm = position_ne_cm * 100.0f; // m to cm
// return if we have already breached polygon
const bool inside_polygon = !Polygon_outside(position_ne_cm, boundary, num_points);
if (inside_polygon != stay_inside) {
return;
}
// Safe_vel will be adjusted to remain within fence.
// We need a separate vector in case adjustment fails,
// e.g. if we are exactly on the boundary.
Vector2f safe_vel_ne_cms(desired_vel_cms);
Vector2f desired_back_vel_cms;
// calc margin in cm
const float margin_cm = MAX(margin * 100.0f, 0.0f);
// for stopping
const float speed = safe_vel_ne_cms.length();
Vector2f stopping_point_plus_margin_ne_cm;
if (!desired_vel_cms.is_zero()) {
stopping_point_plus_margin_ne_cm = position_ne_cm + safe_vel_ne_cms*((2.0f + margin_cm + get_stopping_distance(kP, accel_cmss, speed))/speed);
}
// for backing away
Vector2f quad_1_back_vel_ne_cms, quad_2_back_vel_ne_cms, quad_3_back_vel_ne_cms, quad_4_back_vel_ne_cms;
for (uint16_t i=0; i= num_points) {
j = 0;
}
// end points of current edge
Vector2f start = boundary[j];
Vector2f end = boundary[i];
Vector2f vector_to_boundary_ne_cm = Vector2f::closest_point(position_ne_cm, start, end) - position_ne_cm;
// back away if vehicle has breached margin
if (is_negative(vector_to_boundary_ne_cm.length() - margin_cm)) {
calc_backup_velocity_2D(kP, accel_cmss, quad_1_back_vel_ne_cms, quad_2_back_vel_ne_cms, quad_3_back_vel_ne_cms, quad_4_back_vel_ne_cms, margin_cm - vector_to_boundary_ne_cm.length(), vector_to_boundary_ne_cm, dt);
}
// exit immediately if no desired velocity
if (desired_vel_cms.is_zero()) {
continue;
}
switch (_behavior) {
case (BEHAVIOR_SLIDE): {
// vector from current position to closest point on current edge
Vector2f limit_direction_ne_cm = vector_to_boundary_ne_cm;
// distance to closest point
const float limit_distance_cm = limit_direction_ne_cm.length();
if (is_zero(limit_distance_cm)) {
// We are exactly on the edge - treat this as a fence breach.
// i.e. do not adjust velocity.
return;
}
// We are strictly inside the given edge.
// Adjust velocity to not violate this edge.
limit_direction_ne_cm /= limit_distance_cm;
limit_velocity_NE(kP, accel_cmss, safe_vel_ne_cms, limit_direction_ne_cm, MAX(limit_distance_cm - margin_cm, 0.0f), dt);
break;
}
case (BEHAVIOR_STOP): {
// find intersection_ne_cm with line segment
Vector2f intersection_ne_cm;
if (Vector2f::segment_intersection(position_ne_cm, stopping_point_plus_margin_ne_cm, start, end, intersection_ne_cm)) {
// vector from current position to point on current edge
Vector2f limit_direction_ne_cm = intersection_ne_cm - position_ne_cm;
const float limit_distance_cm = limit_direction_ne_cm.length();
if (is_zero(limit_distance_cm)) {
// We are exactly on the edge - treat this as a fence breach.
// i.e. do not adjust velocity.
return;
}
if (limit_distance_cm <= margin_cm) {
// we are within the margin so stop vehicle
safe_vel_ne_cms.zero();
} else {
// vehicle inside the given edge, adjust velocity to not violate this edge
limit_direction_ne_cm /= limit_distance_cm;
limit_velocity_NE(kP, accel_cmss, safe_vel_ne_cms, limit_direction_ne_cm, MAX(limit_distance_cm - margin_cm, 0.0f), dt);
}
}
break;
}
}
}
// desired backup velocity is sum of maximum velocity component in each quadrant
desired_back_vel_cms = quad_1_back_vel_ne_cms + quad_2_back_vel_ne_cms + quad_3_back_vel_ne_cms + quad_4_back_vel_ne_cms;
// set modified desired velocity vector or back away velocity vector
desired_vel_cms = safe_vel_ne_cms;
backup_vel_ne_cms = desired_back_vel_cms;
}
/*
* Computes distance required to stop, given current speed.
*
* Implementation copied from AC_PosControl.
*/
float AC_Avoid::get_stopping_distance(float kP, float accel_cmss, float speed_cms) const
{
// avoid divide by zero by using current position if the velocity is below 10cm/s, kP is very low or acceleration is zero
if (accel_cmss <= 0.0f || is_zero(speed_cms)) {
return 0.0f;
}
// handle linear deceleration
if (kP <= 0.0f) {
return 0.5f * sq(speed_cms) / accel_cmss;
}
// calculate distance within which we can stop
// accel_cmss/kP is the point at which velocity switches from linear to sqrt
if (speed_cms < accel_cmss/kP) {
return speed_cms/kP;
} else {
// accel_cmss/(2.0f*kP*kP) is the distance at which we switch from linear to sqrt response
return accel_cmss/(2.0f*kP*kP) + (speed_cms*speed_cms)/(2.0f*accel_cmss);
}
}
#if AP_AVOIDANCE_ALTHOLD_ENABLED
// convert distance (in meters) to a lean percentage (in 0~1 range) for use in manual flight modes
float AC_Avoid::distance_m_to_lean_norm(float dist_m) const
{
// ignore objects beyond DIST_MAX
if (dist_m < 0.0f || dist_m >= _dist_max_m || _dist_max_m <= 0.0f) {
return 0.0f;
}
// inverted but linear response
return 1.0f - (dist_m / _dist_max_m);
}
// returns the maximum positive and negative roll and pitch percentages (in -1 ~ +1 range) based on the proximity sensor
void AC_Avoid::get_proximity_roll_pitch_norm(float &roll_positive_norm, float &roll_negative_norm, float &pitch_positive_norm, float &pitch_negative_norm) const
{
#if HAL_PROXIMITY_ENABLED
AP_Proximity *proximity = AP::proximity();
if (proximity == nullptr) {
return;
}
AP_Proximity &_proximity = *proximity;
const uint8_t obj_count = _proximity.get_object_count();
// if no objects return
if (obj_count == 0) {
return;
}
// calculate maximum roll, pitch values from objects
for (uint8_t i=0; i 0.0f) {
roll_positive_norm = MAX(roll_positive_norm, roll_norm);
} else if (roll_norm < 0.0f) {
roll_negative_norm = MIN(roll_negative_norm, roll_norm);
}
if (pitch_norm > 0.0f) {
pitch_positive_norm = MAX(pitch_positive_norm, pitch_norm);
} else if (pitch_norm < 0.0f) {
pitch_negative_norm = MIN(pitch_negative_norm, pitch_norm);
}
}
}
}
#endif // HAL_PROXIMITY_ENABLED
}
#endif // AP_AVOIDANCE_ALTHOLD_ENABLED
// singleton instance
AC_Avoid *AC_Avoid::_singleton;
namespace AP {
AC_Avoid *ac_avoid()
{
return AC_Avoid::get_singleton();
}
}
#endif // !APM_BUILD_TYPE(APM_BUILD_ArduPlane)
#endif // AP_AVOIDANCE_ENABLED