ardupilot/libraries/AP_Proximity/AP_Proximity_MAV.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_HAL/AP_HAL.h>
#include "AP_Proximity_MAV.h"
#include <AP_SerialManager/AP_SerialManager.h>
#include <ctype.h>
#include <stdio.h>
extern const AP_HAL::HAL& hal;
#define PROXIMITY_MAV_TIMEOUT_MS 500 // distance messages must arrive within this many milliseconds
/*
The constructor also initialises the proximity sensor. Note that this
constructor is not called until detect() returns true, so we
already know that we should setup the proximity sensor
*/
AP_Proximity_MAV::AP_Proximity_MAV(AP_Proximity &_frontend,
AP_Proximity::Proximity_State &_state) :
AP_Proximity_Backend(_frontend, _state)
{
}
// update the state of the sensor
void AP_Proximity_MAV::update(void)
{
// check for timeout and set health status
if ((_last_update_ms == 0 || (AP_HAL::millis() - _last_update_ms > PROXIMITY_MAV_TIMEOUT_MS)) &&
(_last_upward_update_ms == 0 || (AP_HAL::millis() - _last_upward_update_ms > PROXIMITY_MAV_TIMEOUT_MS))) {
set_status(AP_Proximity::Proximity_NoData);
} else {
set_status(AP_Proximity::Proximity_Good);
}
}
// get distance upwards in meters. returns true on success
bool AP_Proximity_MAV::get_upward_distance(float &distance) const
{
if ((_last_upward_update_ms != 0) && (AP_HAL::millis() - _last_upward_update_ms <= PROXIMITY_MAV_TIMEOUT_MS)) {
distance = _distance_upward;
return true;
}
return false;
}
// handle mavlink DISTANCE_SENSOR messages
void AP_Proximity_MAV::handle_msg(mavlink_message_t *msg)
{
if (msg->msgid == MAVLINK_MSG_ID_DISTANCE_SENSOR) {
mavlink_distance_sensor_t packet;
mavlink_msg_distance_sensor_decode(msg, &packet);
// store distance to appropriate sector based on orientation field
if (packet.orientation <= MAV_SENSOR_ROTATION_YAW_315) {
uint8_t sector = packet.orientation;
_angle[sector] = sector * 45;
_distance[sector] = packet.current_distance / 100.0f;
_distance_min = packet.min_distance / 100.0f;
_distance_max = packet.max_distance / 100.0f;
_distance_valid[sector] = (_distance[sector] >= _distance_min) && (_distance[sector] <= _distance_max);
_last_update_ms = AP_HAL::millis();
update_boundary_for_sector(sector);
}
// store upward distance
if (packet.orientation == MAV_SENSOR_ROTATION_PITCH_90) {
_distance_upward = packet.current_distance / 100.0f;
_last_upward_update_ms = AP_HAL::millis();
}
return;
}
if (msg->msgid == MAVLINK_MSG_ID_OBSTACLE_DISTANCE) {
mavlink_obstacle_distance_t packet;
mavlink_msg_obstacle_distance_decode(msg, &packet);
// check increment (message's sector width)
uint8_t increment = packet.increment;
if (packet.increment == 0) {
return;
}
const float MAX_DISTANCE = 9999.0f;
const uint8_t total_distances = MIN(360.0f / increment, 72);
// set distance min and max
_distance_min = packet.min_distance / 100.0f;
_distance_max = packet.max_distance / 100.0f;
_last_update_ms = AP_HAL::millis();
// get user configured yaw correction from front end
const float yaw_correction = constrain_float(frontend.get_yaw_correction(state.instance), -360.0f, +360.0f);
float dir_correction;
if (frontend.get_orientation(state.instance) == 0) {
dir_correction = 1.0f;
} else {
dir_correction = -1.0f;
}
// initialise updated array and proximity sector angles (to closest object) and distances
bool sector_updated[_num_sectors];
float sector_width_half[_num_sectors];
for (uint8_t i = 0; i < _num_sectors; i++) {
sector_updated[i] = false;
sector_width_half[i] = _sector_width_deg[i] * 0.5f;
_angle[i] = _sector_middle_deg[i];
_distance[i] = MAX_DISTANCE;
}
// iterate over message's sectors
for (uint8_t j = 0; j < total_distances; j++) {
const float packet_distance_m = packet.distances[j] * 0.01f;
const float mid_angle = wrap_360(j * increment * dir_correction + yaw_correction);
// iterate over proximity sectors
for (uint8_t i = 0; i < _num_sectors; i++) {
float angle_diff = fabsf(wrap_180(_sector_middle_deg[i] - mid_angle));
// update distance array sector with shortest distance from message
if ((angle_diff <= sector_width_half[i]) && (packet_distance_m < _distance[i])) {
_distance[i] = packet_distance_m;
_angle[i] = mid_angle;
sector_updated[i] = true;
}
}
}
// update proximity sectors validity and boundary point
for (uint8_t i = 0; i < _num_sectors; i++) {
_distance_valid[i] = (_distance[i] >= _distance_min) && (_distance[i] <= _distance_max);
if (sector_updated[i]) {
update_boundary_for_sector(i);
}
}
}
}