ardupilot/libraries/AP_Proximity/AP_Proximity_Boundary_3D.cpp

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/*
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 <http://www.gnu.org/licenses/>.
*/
#include "AP_Proximity_Boundary_3D.h"
#if HAL_PROXIMITY_ENABLED
#include "AP_Proximity_Backend.h"
/*
Constructor.
This incorporates initialisation as well.
*/
AP_Proximity_Boundary_3D::AP_Proximity_Boundary_3D()
{
// initialise sector edge vector used for building the boundary fence
init();
}
// initialise the boundary and sector_edge_vector array used for object avoidance
// should be called if the sector_middle_deg or _sector_width_deg arrays are changed
void AP_Proximity_Boundary_3D::init()
{
for (uint8_t layer=0; layer < PROXIMITY_NUM_LAYERS; layer++) {
const float pitch = ((float)_pitch_middle_deg[layer]);
for (uint8_t sector=0; sector < PROXIMITY_NUM_SECTORS; sector++) {
const float angle_rad = ((float)_sector_middle_deg[sector]+(PROXIMITY_SECTOR_WIDTH_DEG/2.0f));
_sector_edge_vector[layer][sector].offset_bearing(angle_rad, pitch, 100.0f);
_boundary_points[layer][sector] = _sector_edge_vector[layer][sector] * PROXIMITY_BOUNDARY_DIST_DEFAULT;
}
}
}
// returns face corresponding to the provided yaw and (optionally) pitch
// pitch is the vertical body-frame angle (in degrees) to the obstacle (0=directly ahead, 90 is above the vehicle)
// yaw is the horizontal body-frame angle (in degrees) to the obstacle (0=directly ahead of the vehicle, 90 is to the right of the vehicle)
AP_Proximity_Boundary_3D::Face AP_Proximity_Boundary_3D::get_face(float pitch, float yaw) const
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{
const uint8_t sector = wrap_360(yaw + (PROXIMITY_SECTOR_WIDTH_DEG * 0.5f)) / 45.0f;
const float pitch_limited = constrain_float(pitch, -75.0f, 74.9f);
const uint8_t layer = (pitch_limited + 75.0f)/PROXIMITY_PITCH_WIDTH_DEG;
return Face{layer, sector};
}
// Set the actual body-frame angle(yaw), pitch, and distance of the detected object.
// This method will also mark the sector and layer to be "valid", so this distance can be used for Obstacle Avoidance
void AP_Proximity_Boundary_3D::set_face_attributes(const Face &face, float pitch, float angle, float distance)
{
if (!face.valid()) {
return;
}
_angle[face.layer][face.sector] = angle;
_pitch[face.layer][face.sector] = pitch;
_distance[face.layer][face.sector] = distance;
_distance_valid[face.layer][face.sector] = true;
// apply filter
set_filtered_distance(face, distance);
// update boundary used for simple avoidance
update_boundary(face);
}
// apply a new cutoff_freq to low-pass filter
void AP_Proximity_Boundary_3D::apply_filter_freq(float cutoff_freq)
{
for (uint8_t layer=0; layer < PROXIMITY_NUM_LAYERS; layer++) {
for (uint8_t sector=0; sector < PROXIMITY_NUM_SECTORS; sector++) {
_filtered_distance[layer][sector].set_cutoff_frequency(cutoff_freq);
}
}
}
// Apply low pass filter on the raw distance
void AP_Proximity_Boundary_3D::set_filtered_distance(const Face &face, float distance)
{
if (!face.valid()) {
return;
}
if (!is_equal(_filtered_distance[face.layer][face.sector].get_cutoff_freq(), _filter_freq)) {
// cutoff freq has changed
apply_filter_freq(_filter_freq);
}
const uint32_t now_ms = AP_HAL::millis();
const uint32_t dt = now_ms - _last_update_ms[face.layer][face.sector];
if (dt < PROXIMITY_FILT_RESET_TIME) {
_filtered_distance[face.layer][face.sector].apply(distance, dt* 0.001f);
} else {
// reset filter since last distance was passed a long time back
_filtered_distance[face.layer][face.sector].reset(distance);
}
_last_update_ms[face.layer][face.sector] = now_ms;
}
// update boundary points used for object avoidance based on a single sector and pitch distance changing
// the boundary points lie on the line between sectors meaning two boundary points may be updated based on a single sector's distance changing
// the boundary point is set to the shortest distance found in the two adjacent sectors, this is a conservative boundary around the vehicle
void AP_Proximity_Boundary_3D::update_boundary(const Face &face)
{
// sanity check
if (!face.valid()) {
return;
}
const uint8_t layer = face.layer;
const uint8_t sector = face.sector;
// find adjacent sector (clockwise)
const uint8_t next_sector = get_next_sector(sector);
// boundary point lies on the line between the two sectors at the shorter distance found in the two sectors
float shortest_distance = PROXIMITY_BOUNDARY_DIST_DEFAULT;
if (_distance_valid[layer][sector] && _distance_valid[layer][next_sector]) {
shortest_distance = MIN(_filtered_distance[layer][sector].get(), _filtered_distance[layer][next_sector].get());
} else if (_distance_valid[layer][sector]) {
shortest_distance = _filtered_distance[layer][sector].get();
} else if (_distance_valid[layer][next_sector]) {
shortest_distance = _filtered_distance[layer][next_sector].get();
}
if (shortest_distance < PROXIMITY_BOUNDARY_DIST_MIN) {
shortest_distance = PROXIMITY_BOUNDARY_DIST_MIN;
}
_boundary_points[layer][sector] = _sector_edge_vector[layer][sector] * shortest_distance;
// if the next sector (clockwise) has an invalid distance, set boundary to create a cup like boundary
if (!_distance_valid[layer][next_sector]) {
_boundary_points[layer][next_sector] = _sector_edge_vector[layer][next_sector] * shortest_distance;
}
// repeat for edge between sector and previous sector
const uint8_t prev_sector = get_prev_sector(sector);
shortest_distance = PROXIMITY_BOUNDARY_DIST_DEFAULT;
if (_distance_valid[layer][prev_sector] && _distance_valid[layer][sector]) {
shortest_distance = MIN(_filtered_distance[layer][prev_sector].get(), _filtered_distance[layer][sector].get());
} else if (_distance_valid[layer][prev_sector]) {
shortest_distance = _filtered_distance[layer][prev_sector].get();
} else if (_distance_valid[layer][sector]) {
shortest_distance = _filtered_distance[layer][sector].get();
}
_boundary_points[layer][prev_sector] = _sector_edge_vector[layer][prev_sector] * shortest_distance;
// if the sector counter-clockwise from the previous sector has an invalid distance, set boundary to create a cup-like boundary
const uint8_t prev_sector_ccw = get_prev_sector(prev_sector);
if (!_distance_valid[layer][prev_sector_ccw]) {
_boundary_points[layer][prev_sector_ccw] = _sector_edge_vector[layer][prev_sector_ccw] * shortest_distance;
}
}
// reset boundary. marks all distances as invalid
void AP_Proximity_Boundary_3D::reset()
{
for (uint8_t layer=0; layer < PROXIMITY_NUM_LAYERS; layer++) {
for (uint8_t sector=0; sector < PROXIMITY_NUM_SECTORS; sector++) {
_distance_valid[layer][sector] = false;
}
}
}
// Reset this location, specified by Face object, back to default
// i.e Distance is marked as not-valid, and set to a large number.
void AP_Proximity_Boundary_3D::reset_face(const Face &face)
{
if (!face.valid()) {
return;
}
_distance_valid[face.layer][face.sector] = false;
// update simple avoidance boundary
update_boundary(face);
}
// check if a face has valid distance even if it was updated a long time back
void AP_Proximity_Boundary_3D::check_face_timeout()
{
for (uint8_t layer=0; layer < PROXIMITY_NUM_LAYERS; layer++) {
for (uint8_t sector=0; sector < PROXIMITY_NUM_SECTORS; sector++) {
if (_distance_valid[layer][sector]) {
if ((AP_HAL::millis() - _last_update_ms[layer][sector]) > PROXIMITY_FACE_RESET_MS) {
// this face has a valid distance but wasn't updated for a long time, reset it
AP_Proximity_Boundary_3D::Face face{layer, sector};
reset_face(face);
}
}
}
}
}
// get distance for a face. returns true on success and fills in distance argument with distance in meters
bool AP_Proximity_Boundary_3D::get_distance(const Face &face, float &distance) const
{
if (!face.valid()) {
return false;
}
if (_distance_valid[face.layer][face.sector]) {
distance = _distance[face.layer][face.sector];
return true;
}
return false;
}
// get the total number of obstacles
uint8_t AP_Proximity_Boundary_3D::get_obstacle_count() const
{
return PROXIMITY_NUM_LAYERS * PROXIMITY_NUM_SECTORS;
}
// Converts obstacle_num passed from avoidance library into appropriate face of the boundary
// Returns false if the face is invalid
// "update_boundary" method manipulates two sectors ccw and one sector cw from any valid face.
// Any boundary that does not fall into these manipulated faces are useless, and will be marked as false
// The resultant is packed into a Boundary Location object and returned by reference as "face"
bool AP_Proximity_Boundary_3D::convert_obstacle_num_to_face(uint8_t obstacle_num, Face& face) const
{
// obstacle num is just "flattened layers, and sectors"
const uint8_t layer = obstacle_num / PROXIMITY_NUM_SECTORS;
const uint8_t sector = obstacle_num % PROXIMITY_NUM_SECTORS;
face.sector = sector;
face.layer = layer;
uint8_t valid_sector = sector;
// check for 3 adjacent sectors
for (uint8_t i=0; i < 3; i++) {
if (_distance_valid[layer][valid_sector]) {
// update boundary has manipulated this face
return true;
}
valid_sector = get_next_sector(valid_sector);
}
// this face was not manipulated by "update_boundary" and is stale. Don't use it
return false;
}
// Appropriate layer and sector are found from the passed obstacle_num
// This function then draws a line between this sector, and sector + 1 at the given layer
// Then returns the closest point on this line from vehicle, in body-frame.
// Used by GPS based Simple Avoidance
// False is returned if the obstacle_num provided does not produce a valid obstacle
bool AP_Proximity_Boundary_3D::get_obstacle(uint8_t obstacle_num, Vector3f& vec_to_obstacle) const
{
Face face;
if (!convert_obstacle_num_to_face(obstacle_num, face)) {
// not a valid face
return false;
}
const uint8_t sector_end = face.sector;
const uint8_t sector_start = get_next_sector(face.sector);
const Vector3f start = _boundary_points[face.layer][sector_start];
const Vector3f end = _boundary_points[face.layer][sector_end];
vec_to_obstacle = Vector3f::point_on_line_closest_to_other_point(start, end, Vector3f{});
return true;
}
// Appropriate layer and sector are found from the passed obstacle_num
// This function then draws a line between this sector, and sector + 1 at the given layer
// Then returns the closest point on this line from the segment that was passed, in body-frame.
// Addionally a 3-D plane is constructed using the closest point found above as normal, and a point on the line segment in the boundary.
// True is returned when the passed line segment intersects this plane.
// This helps us know if the passed line segment was in the direction of the boundary, or going in a different direction.
// Used by GPS based Simple Avoidance - for "brake mode"
// False is returned if the obstacle_num provided does not produce a valid obstacle
bool AP_Proximity_Boundary_3D::closest_point_from_segment_to_obstacle(uint8_t obstacle_num, const Vector3f& seg_start, const Vector3f& seg_end, Vector3f& closest_point) const
{
Face face;
if (!convert_obstacle_num_to_face(obstacle_num, face)) {
// not a valid a face
return false;
}
const uint8_t sector_end = face.sector;
const uint8_t sector_start = get_next_sector(face.sector);
const Vector3f start = _boundary_points[face.layer][sector_start];
const Vector3f end = _boundary_points[face.layer][sector_end];
// closest point between passed line segment and boundary
Vector3f::segment_to_segment_closest_point(seg_start, seg_end, start, end, closest_point);
if (closest_point == start) {
// draw a plane using the closest point as normal vector, and a point on the boundary
// return false if the passed segment does not intersect the plane
return Vector3f::segment_plane_intersect(seg_start, seg_end, closest_point, end);
}
return Vector3f::segment_plane_intersect(seg_start, seg_end, closest_point, start);
}
// get distance and angle to closest object (used for pre-arm check)
// returns true on success, false if no valid readings
bool AP_Proximity_Boundary_3D::get_closest_object(float& angle_deg, float &distance) const
{
bool closest_found = false;
uint8_t closest_sector = 0;
uint8_t closest_layer = 0;
// check boundary for shortest distance
// only check for middle layers and higher
// lower layers might contain ground, which will give false pre-arm failure
for (uint8_t layer=PROXIMITY_MIDDLE_LAYER; layer<PROXIMITY_NUM_LAYERS; layer++) {
for (uint8_t sector=0; sector<PROXIMITY_NUM_SECTORS; sector++) {
if (_distance_valid[layer][sector]) {
if (!closest_found || (_distance[layer][sector] < _distance[closest_layer][closest_sector])) {
closest_layer = layer;
closest_sector = sector;
closest_found = true;
}
}
}
}
if (closest_found) {
angle_deg = _angle[closest_layer][closest_sector];
distance = _distance[closest_layer][closest_sector];
}
return closest_found;
}
// get number of objects, used for non-GPS avoidance
uint8_t AP_Proximity_Boundary_3D::get_horizontal_object_count() const
{
return PROXIMITY_NUM_SECTORS;
}
// get an object's angle and distance, used for non-GPS avoidance
// returns false if no angle or distance could be returned for some reason
bool AP_Proximity_Boundary_3D::get_horizontal_object_angle_and_distance(uint8_t object_number, float &angle_deg, float &distance) const
{
if ((object_number < PROXIMITY_NUM_SECTORS) && _distance_valid[PROXIMITY_MIDDLE_LAYER][object_number]) {
angle_deg = _angle[PROXIMITY_MIDDLE_LAYER][object_number];
distance = _filtered_distance[PROXIMITY_MIDDLE_LAYER][object_number].get();
return true;
}
return false;
}
// Return filtered distance for the passed in face
bool AP_Proximity_Boundary_3D::get_filtered_distance(const Face &face, float &distance) const
{
if (!face.valid()) {
return false;
}
if (!_distance_valid[face.layer][face.sector]) {
// invalid distace
return false;
}
distance = _filtered_distance[face.layer][face.sector].get();
return true;
}
// Get raw and filtered distances in 8 directions per layer
bool AP_Proximity_Boundary_3D::get_layer_distances(uint8_t layer_number, float dist_max, AP_Proximity::Proximity_Distance_Array &prx_dist_array, AP_Proximity::Proximity_Distance_Array &prx_filt_dist_array) const
{
// cycle through all sectors filling in distances and orientations
// see MAV_SENSOR_ORIENTATION for orientations (0 = forward, 1 = 45 degree clockwise from north, etc)
bool valid_distances = false;
prx_dist_array.offset_valid = 0;
prx_filt_dist_array.offset_valid = 0;
for (uint8_t i=0; i<PROXIMITY_MAX_DIRECTION; i++) {
prx_dist_array.orientation[i] = i;
const AP_Proximity_Boundary_3D::Face face(layer_number, i);
if (!face.valid()) {
return false;
}
if (get_distance(face, prx_dist_array.distance[i]) && get_filtered_distance(face, prx_filt_dist_array.distance[i])) {
valid_distances = true;
prx_dist_array.offset_valid |= (1U << i);
prx_filt_dist_array.offset_valid |= (1U << i);
} else {
prx_dist_array.distance[i] = dist_max;
prx_filt_dist_array.distance[i] = dist_max;
}
}
return valid_distances;
}
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// reset the temporary boundary. This fills in distances with FLT_MAX
void AP_Proximity_Temp_Boundary::reset()
{
for (uint8_t layer=0; layer < PROXIMITY_NUM_LAYERS; layer++) {
for (uint8_t sector=0; sector < PROXIMITY_NUM_SECTORS; sector++) {
_distances[layer][sector] = FLT_MAX;
}
}
}
// add a distance to the temp boundary if it is shorter than any other provided distance since the last time the boundary was reset
// pitch and yaw are in degrees, distance is in meters
void AP_Proximity_Temp_Boundary::add_distance(const AP_Proximity_Boundary_3D::Face &face, float pitch, float yaw, float distance)
{
if (face.valid() && distance < _distances[face.layer][face.sector]) {
_distances[face.layer][face.sector] = distance;
_angle[face.layer][face.sector] = yaw;
_pitch[face.layer][face.sector] = pitch;
}
}
// fill the original 3D boundary with the contents of this temporary boundary
void AP_Proximity_Temp_Boundary::update_3D_boundary(AP_Proximity_Boundary_3D &boundary)
{
for (uint8_t layer=0; layer < PROXIMITY_NUM_LAYERS; layer++) {
for (uint8_t sector=0; sector < PROXIMITY_NUM_SECTORS; sector++) {
if (_distances[layer][sector] < FLT_MAX) {
AP_Proximity_Boundary_3D::Face face{layer, sector};
boundary.set_face_attributes(face, _pitch[layer][sector], _angle[layer][sector], _distances[layer][sector]);
}
}
}
}
#endif // HAL_PROXIMITY_ENABLED