mirror of https://github.com/ArduPilot/ardupilot
1117 lines
48 KiB
C++
1117 lines
48 KiB
C++
/*
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "AC_Avoid.h"
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#include <AP_AHRS/AP_AHRS.h> // AHRS library
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#include <AC_Fence/AC_Fence.h> // Failsafe fence library
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#include <AP_Proximity/AP_Proximity.h>
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#include <AP_Beacon/AP_Beacon.h>
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#include <AP_Logger/AP_Logger.h>
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#include <stdio.h>
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#if APM_BUILD_TYPE(APM_BUILD_Rover)
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# define AP_AVOID_BEHAVE_DEFAULT AC_Avoid::BehaviourType::BEHAVIOR_STOP
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#else
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# define AP_AVOID_BEHAVE_DEFAULT AC_Avoid::BehaviourType::BEHAVIOR_SLIDE
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#endif
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const AP_Param::GroupInfo AC_Avoid::var_info[] = {
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// @Param: ENABLE
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// @DisplayName: Avoidance control enable/disable
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// @Description: Enabled/disable avoidance input sources
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// @Values: 0:None,1:UseFence,2:UseProximitySensor,3:UseFence and UseProximitySensor,4:UseBeaconFence,7:All
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// @Bitmask: 0:UseFence,1:UseProximitySensor,2:UseBeaconFence
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// @User: Standard
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AP_GROUPINFO("ENABLE", 1, AC_Avoid, _enabled, AC_AVOID_DEFAULT),
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// @Param{Copter}: ANGLE_MAX
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// @DisplayName: Avoidance max lean angle in non-GPS flight modes
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// @Description: Max lean angle used to avoid obstacles while in non-GPS modes
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// @Units: cdeg
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// @Range: 0 4500
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// @User: Standard
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AP_GROUPINFO_FRAME("ANGLE_MAX", 2, AC_Avoid, _angle_max, 1000, AP_PARAM_FRAME_COPTER | AP_PARAM_FRAME_HELI | AP_PARAM_FRAME_TRICOPTER),
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// @Param{Copter}: DIST_MAX
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// @DisplayName: Avoidance distance maximum in non-GPS flight modes
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// @Description: Distance from object at which obstacle avoidance will begin in non-GPS modes
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// @Units: m
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// @Range: 1 30
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// @User: Standard
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AP_GROUPINFO_FRAME("DIST_MAX", 3, AC_Avoid, _dist_max, AC_AVOID_NONGPS_DIST_MAX_DEFAULT, AP_PARAM_FRAME_COPTER | AP_PARAM_FRAME_HELI | AP_PARAM_FRAME_TRICOPTER),
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// @Param: MARGIN
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// @DisplayName: Avoidance distance margin in GPS modes
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// @Description: Vehicle will attempt to stay at least this distance (in meters) from objects while in GPS modes
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// @Units: m
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// @Range: 1 10
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// @User: Standard
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AP_GROUPINFO("MARGIN", 4, AC_Avoid, _margin, 2.0f),
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// @Param{Copter}: BEHAVE
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// @DisplayName: Avoidance behaviour
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// @Description: Avoidance behaviour (slide or stop)
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// @Values: 0:Slide,1:Stop
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// @User: Standard
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AP_GROUPINFO_FRAME("BEHAVE", 5, AC_Avoid, _behavior, AP_AVOID_BEHAVE_DEFAULT, AP_PARAM_FRAME_COPTER | AP_PARAM_FRAME_HELI | AP_PARAM_FRAME_TRICOPTER),
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// @Param: BACKUP_SPD
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// @DisplayName: Avoidance maximum backup speed
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// @Description: Maximum speed that will be used to back away from obstacles in GPS modes (m/s). Set zero to disable
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// @Units: m/s
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// @Range: 0 2
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// @User: Standard
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AP_GROUPINFO("BACKUP_SPD", 6, AC_Avoid, _backup_speed_max, 0.5f),
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AP_GROUPEND
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};
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/// Constructor
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AC_Avoid::AC_Avoid()
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{
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_singleton = this;
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AP_Param::setup_object_defaults(this, var_info);
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}
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void AC_Avoid::adjust_velocity(float kP, float accel_cmss, Vector2f &desired_vel_cms, bool &backing_up,float dt)
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{
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// exit immediately if disabled
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if (_enabled == AC_AVOID_DISABLED) {
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return;
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}
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// limit acceleration
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const float accel_cmss_limited = MIN(accel_cmss, AC_AVOID_ACCEL_CMSS_MAX);
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// make a copy of desired velocity since the one that is passed will be modified
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const Vector2f desired_vel_orig = desired_vel_cms;
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// maximum component of desired backup velocity in each quadrant
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Vector2f quad_1_back_vel, quad_2_back_vel, quad_3_back_vel, quad_4_back_vel;
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if ((_enabled & AC_AVOID_STOP_AT_FENCE) > 0) {
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// Store velocity needed to back away from fence
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Vector2f backup_vel_fence;
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adjust_velocity_circle_fence(kP, accel_cmss_limited, desired_vel_cms, backup_vel_fence, dt);
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find_max_quadrant_velocity(backup_vel_fence, quad_1_back_vel, quad_2_back_vel, quad_3_back_vel, quad_4_back_vel);
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// backup_vel_fence is set to zero after each fence incase the velocity is unset from previous methods
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backup_vel_fence.zero();
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adjust_velocity_inclusion_and_exclusion_polygons(kP, accel_cmss_limited, desired_vel_cms, backup_vel_fence, dt);
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find_max_quadrant_velocity(backup_vel_fence, quad_1_back_vel, quad_2_back_vel, quad_3_back_vel, quad_4_back_vel);
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backup_vel_fence.zero();
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adjust_velocity_inclusion_circles(kP, accel_cmss_limited, desired_vel_cms, backup_vel_fence, dt);
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find_max_quadrant_velocity(backup_vel_fence, quad_1_back_vel, quad_2_back_vel, quad_3_back_vel, quad_4_back_vel);
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backup_vel_fence.zero();
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adjust_velocity_exclusion_circles(kP, accel_cmss_limited, desired_vel_cms, backup_vel_fence, dt);
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find_max_quadrant_velocity(backup_vel_fence, quad_1_back_vel, quad_2_back_vel, quad_3_back_vel, quad_4_back_vel);
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}
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if ((_enabled & AC_AVOID_STOP_AT_BEACON_FENCE) > 0) {
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// Store velocity needed to back away from beacon fence
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Vector2f backup_vel_beacon;
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adjust_velocity_beacon_fence(kP, accel_cmss_limited, desired_vel_cms, backup_vel_beacon, dt);
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find_max_quadrant_velocity(backup_vel_beacon, quad_1_back_vel, quad_2_back_vel, quad_3_back_vel, quad_4_back_vel);
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}
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if ((_enabled & AC_AVOID_USE_PROXIMITY_SENSOR) > 0 && _proximity_enabled) {
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// Store velocity needed to back away from physical obstacles
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Vector2f backup_vel_proximity;
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adjust_velocity_proximity(kP, accel_cmss_limited, desired_vel_cms, backup_vel_proximity, dt);
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find_max_quadrant_velocity(backup_vel_proximity, quad_1_back_vel, quad_2_back_vel, quad_3_back_vel, quad_4_back_vel);
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}
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// Desired backup velocity is sum of maximum velocity component in each quadrant
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Vector2f desired_backup_vel = quad_1_back_vel + quad_2_back_vel + quad_3_back_vel + quad_4_back_vel;
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const float max_back_spd_cms = _backup_speed_max * 100.0f;
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if (!desired_backup_vel.is_zero() && is_positive(max_back_spd_cms)) {
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backing_up = true;
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// Constrain backing away speed
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if (desired_backup_vel.length() > max_back_spd_cms) {
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desired_backup_vel = desired_backup_vel.normalized() * max_back_spd_cms;
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}
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if ((AC_Avoid::BehaviourType)_behavior.get() == BEHAVIOR_SLIDE) {
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// project desired velocity towards backup velocity
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Vector2f projected_vel = desired_vel_cms.projected(desired_backup_vel);
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// subtract this projection since we are already going in that direction
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desired_vel_cms -= projected_vel;
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desired_vel_cms += desired_backup_vel;
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} else {
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// back away to stopping position
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desired_vel_cms = desired_backup_vel;
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}
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}
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// only log results if velocity has been modified to avoid fence/obstacle
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if (desired_vel_orig != desired_vel_cms) {
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// log at not more than 10hz (adjust_velocity method can be potentially called at 400hz!)
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uint32_t now = AP_HAL::millis();
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if ((now - _last_log_ms) > 100) {
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_last_log_ms = now;
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AP::logger().Write_SimpleAvoidance(true, desired_vel_orig, desired_vel_cms, backing_up);
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}
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}
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}
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// convenience function to accept Vector3f. Only x and y are adjusted
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void AC_Avoid::adjust_velocity(float kP, float accel_cmss, Vector3f &desired_vel_cms, float dt)
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{
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Vector2f des_vel_xy(desired_vel_cms.x, desired_vel_cms.y);
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adjust_velocity(kP, accel_cmss, des_vel_xy, dt);
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desired_vel_cms.x = des_vel_xy.x;
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desired_vel_cms.y = des_vel_xy.y;
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}
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// adjust desired horizontal speed so that the vehicle stops before the fence or object
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// accel (maximum acceleration/deceleration) is in m/s/s
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// heading is in radians
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// speed is in m/s
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// kP should be zero for linear response, non-zero for non-linear response
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void AC_Avoid::adjust_speed(float kP, float accel, float heading, float &speed, float dt)
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{
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// convert heading and speed into velocity vector
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Vector2f vel_xy;
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vel_xy.x = cosf(heading) * speed * 100.0f;
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vel_xy.y = sinf(heading) * speed * 100.0f;
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bool backing_up = false;
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adjust_velocity(kP, accel * 100.0f, vel_xy, backing_up, dt);
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if (backing_up) {
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// back up
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if (fabsf(wrap_180(degrees(vel_xy.angle())) - degrees(heading)) > 90.0f) {
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// Big difference between the direction of velocity vector and actual heading therefore we need to reverse the direction
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speed = -vel_xy.length() * 0.01f;
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} else {
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speed = vel_xy.length() * 0.01f;
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}
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return;
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}
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// No need to back up so adjust speed towards zero if needed
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if (is_negative(speed)) {
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speed = -vel_xy.length() * 0.01f;
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} else {
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speed = vel_xy.length() * 0.01f;
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}
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}
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// adjust vertical climb rate so vehicle does not break the vertical fence
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void AC_Avoid::adjust_velocity_z(float kP, float accel_cmss, float& climb_rate_cms, float dt)
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{
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// exit immediately if disabled
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if (_enabled == AC_AVOID_DISABLED) {
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return;
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}
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// do not adjust climb_rate if level or descending
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if (climb_rate_cms <= 0.0f) {
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return;
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}
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// limit acceleration
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const float accel_cmss_limited = MIN(accel_cmss, AC_AVOID_ACCEL_CMSS_MAX);
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bool limit_alt = false;
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float alt_diff = 0.0f; // distance from altitude limit to vehicle in metres (positive means vehicle is below limit)
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const AP_AHRS &_ahrs = AP::ahrs();
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// calculate distance below fence
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AC_Fence *fence = AP::fence();
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if ((_enabled & AC_AVOID_STOP_AT_FENCE) > 0 && fence && (fence->get_enabled_fences() & AC_FENCE_TYPE_ALT_MAX) > 0) {
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// calculate distance from vehicle to safe altitude
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float veh_alt;
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_ahrs.get_relative_position_D_home(veh_alt);
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// _fence.get_safe_alt_max() is UP, veh_alt is DOWN:
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alt_diff = fence->get_safe_alt_max() + veh_alt;
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limit_alt = true;
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}
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// calculate distance to (e.g.) optical flow altitude limit
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// AHRS values are always in metres
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float alt_limit;
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float curr_alt;
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if (_ahrs.get_hgt_ctrl_limit(alt_limit) &&
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_ahrs.get_relative_position_D_origin(curr_alt)) {
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// alt_limit is UP, curr_alt is DOWN:
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const float ctrl_alt_diff = alt_limit + curr_alt;
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if (!limit_alt || ctrl_alt_diff < alt_diff) {
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alt_diff = ctrl_alt_diff;
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limit_alt = true;
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}
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}
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// get distance from proximity sensor
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float proximity_alt_diff;
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AP_Proximity *proximity = AP::proximity();
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if (proximity && proximity->get_upward_distance(proximity_alt_diff)) {
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proximity_alt_diff -= _margin;
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if (!limit_alt || proximity_alt_diff < alt_diff) {
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alt_diff = proximity_alt_diff;
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limit_alt = true;
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}
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}
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// limit climb rate
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if (limit_alt) {
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// do not allow climbing if we've breached the safe altitude
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if (alt_diff <= 0.0f) {
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climb_rate_cms = MIN(climb_rate_cms, 0.0f);
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return;
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}
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// limit climb rate
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const float max_speed = get_max_speed(kP, accel_cmss_limited, alt_diff*100.0f, dt);
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climb_rate_cms = MIN(max_speed, climb_rate_cms);
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_last_limit_time = AP_HAL::millis();
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}
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}
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// adjust roll-pitch to push vehicle away from objects
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// roll and pitch value are in centi-degrees
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void AC_Avoid::adjust_roll_pitch(float &roll, float &pitch, float veh_angle_max)
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{
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// exit immediately if proximity based avoidance is disabled
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if ((_enabled & AC_AVOID_USE_PROXIMITY_SENSOR) == 0 || !_proximity_enabled) {
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return;
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}
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// exit immediately if angle max is zero
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if (_angle_max <= 0.0f || veh_angle_max <= 0.0f) {
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return;
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}
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float roll_positive = 0.0f; // maximum positive roll value
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float roll_negative = 0.0f; // minimum negative roll value
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float pitch_positive = 0.0f; // maximum positive pitch value
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float pitch_negative = 0.0f; // minimum negative pitch value
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// get maximum positive and negative roll and pitch percentages from proximity sensor
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get_proximity_roll_pitch_pct(roll_positive, roll_negative, pitch_positive, pitch_negative);
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// add maximum positive and negative percentages together for roll and pitch, convert to centi-degrees
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Vector2f rp_out((roll_positive + roll_negative) * 4500.0f, (pitch_positive + pitch_negative) * 4500.0f);
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// apply avoidance angular limits
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// the object avoidance lean angle is never more than 75% of the total angle-limit to allow the pilot to override
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const float angle_limit = constrain_float(_angle_max, 0.0f, veh_angle_max * AC_AVOID_ANGLE_MAX_PERCENT);
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float vec_len = rp_out.length();
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if (vec_len > angle_limit) {
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rp_out *= (angle_limit / vec_len);
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}
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// add passed in roll, pitch angles
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rp_out.x += roll;
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rp_out.y += pitch;
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// apply total angular limits
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vec_len = rp_out.length();
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if (vec_len > veh_angle_max) {
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rp_out *= (veh_angle_max / vec_len);
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}
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// return adjusted roll, pitch
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roll = rp_out.x;
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pitch = rp_out.y;
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}
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/*
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* Limits the component of desired_vel_cms in the direction of the unit vector
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* limit_direction to be at most the maximum speed permitted by the limit_distance_cm.
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*
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* Uses velocity adjustment idea from Randy's second email on this thread:
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* https://groups.google.com/forum/#!searchin/drones-discuss/obstacle/drones-discuss/QwUXz__WuqY/qo3G8iTLSJAJ
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*/
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void AC_Avoid::limit_velocity(float kP, float accel_cmss, Vector2f &desired_vel_cms, const Vector2f& limit_direction, float limit_distance_cm, float dt)
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{
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const float max_speed = get_max_speed(kP, accel_cmss, limit_distance_cm, dt);
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// project onto limit direction
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const float speed = desired_vel_cms * limit_direction;
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if (speed > max_speed) {
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// subtract difference between desired speed and maximum acceptable speed
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desired_vel_cms += limit_direction*(max_speed - speed);
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_last_limit_time = AP_HAL::millis();
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}
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}
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/*
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* Compute the back away velocity required to avoid breaching margin
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* INPUT: This method requires the breach in margin distance (back_distance_cm), direction towards the breach (limit_direction)
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* 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
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* OUTPUT: The method then outputs four velocities (quad1/2/3/4_back_vel_cms), which correspond to the maximum final desired backup velocity in each quadrant
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*/
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void AC_Avoid::calc_backup_velocity(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)
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{
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if (limit_direction.is_zero()) {
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// protect against divide by zero
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return;
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}
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// speed required to move away the exact distance that we have breached the margin with
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const float back_speed = get_max_speed(kP, 0.4f * accel_cmss, fabsf(back_distance_cm), dt);
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// direction to the obstacle
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limit_direction.normalize();
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// move in the opposite direction with the required speed
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Vector2f back_direction_vel = limit_direction * (-back_speed);
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// divide the vector into quadrants, find maximum velocity component in each quadrant
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find_max_quadrant_velocity(back_direction_vel, quad1_back_vel_cms, quad2_back_vel_cms, quad3_back_vel_cms, quad4_back_vel_cms);
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}
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/*
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* Calculate maximum velocity vector that can be formed in each quadrant
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* This method takes the desired backup velocity, and four other velocities corresponding to each quadrant
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* The desired velocity is then fit into one of the 4 quadrant velocities as per the sign of its components
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* This ensures that if we have multiple backup velocities, we can get the maximum of all of those velocities in each quadrant
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*/
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void AC_Avoid::find_max_quadrant_velocity(Vector2f &desired_vel, Vector2f &quad1_vel, Vector2f &quad2_vel, Vector2f &quad3_vel, Vector2f &quad4_vel)
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{
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if (desired_vel.is_zero()) {
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return;
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}
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// first quadrant: +ve x, +ve y direction
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if (is_positive(desired_vel.x) && is_positive(desired_vel.y)) {
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quad1_vel = Vector2f{MAX(quad1_vel.x, desired_vel.x), MAX(quad1_vel.y,desired_vel.y)};
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}
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// second quadrant: -ve x, +ve y direction
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if (is_negative(desired_vel.x) && is_positive(desired_vel.y)) {
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quad2_vel = Vector2f{MIN(quad2_vel.x, desired_vel.x), MAX(quad2_vel.y,desired_vel.y)};
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}
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// third quadrant: -ve x, -ve y direction
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if (is_negative(desired_vel.x) && is_negative(desired_vel.y)) {
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quad3_vel = Vector2f{MIN(quad3_vel.x, desired_vel.x), MIN(quad3_vel.y,desired_vel.y)};
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}
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// fourth quadrant: +ve x, -ve y direction
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if (is_positive(desired_vel.x) && is_negative(desired_vel.y)) {
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quad4_vel = Vector2f{MAX(quad4_vel.x, desired_vel.x), MIN(quad4_vel.y,desired_vel.y)};
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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_cmss, float distance_cm, float dt) const
|
|
{
|
|
if (is_zero(kP)) {
|
|
return safe_sqrt(2.0f * distance_cm * accel_cmss);
|
|
} else {
|
|
return AC_AttitudeControl::sqrt_controller(distance_cm, kP, accel_cmss, dt);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Adjusts the desired velocity for the circular fence.
|
|
*/
|
|
void AC_Avoid::adjust_velocity_circle_fence(float kP, float accel_cmss, Vector2f &desired_vel_cms, Vector2f &backup_vel, 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 = desired_vel_cms.length();
|
|
if (is_zero(desired_speed)) {
|
|
// 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_xy;
|
|
if (!_ahrs.get_relative_position_NE_home(position_xy)) {
|
|
// we have no idea where we are....
|
|
return;
|
|
}
|
|
position_xy *= 100.0f; // m -> cm
|
|
|
|
// get the fence radius in cm
|
|
const float fence_radius = _fence.get_radius() * 100.0f;
|
|
// get the margin to the fence in cm
|
|
const float margin_cm = _fence.get_margin() * 100.0f;
|
|
|
|
if (margin_cm > fence_radius) {
|
|
return;
|
|
}
|
|
|
|
// get vehicle distance from home
|
|
const float dist_from_home = position_xy.length();
|
|
if (dist_from_home > fence_radius) {
|
|
// outside of circular fence, no velocity adjustments
|
|
return;
|
|
}
|
|
const float distance_to_boundary = fence_radius - dist_from_home;
|
|
|
|
// for backing away
|
|
Vector2f quad_1_back_vel, quad_2_back_vel, quad_3_back_vel, quad_4_back_vel;
|
|
|
|
// back away if vehicle has breached margin
|
|
if (is_negative(distance_to_boundary - margin_cm)) {
|
|
calc_backup_velocity(kP, accel_cmss, quad_1_back_vel, quad_2_back_vel, quad_3_back_vel, quad_4_back_vel, margin_cm - distance_to_boundary, position_xy, dt);
|
|
}
|
|
// desired backup velocity is sum of maximum velocity component in each quadrant
|
|
backup_vel = quad_1_back_vel + quad_2_back_vel + quad_3_back_vel + quad_4_back_vel;
|
|
|
|
// vehicle is inside the circular fence
|
|
if ((AC_Avoid::BehaviourType)_behavior.get() == BEHAVIOR_SLIDE) {
|
|
// implement sliding behaviour
|
|
const Vector2f stopping_point = position_xy + desired_vel_cms*(get_stopping_distance(kP, accel_cmss, desired_speed)/desired_speed);
|
|
const float stopping_point_dist_from_home = stopping_point.length();
|
|
if (stopping_point_dist_from_home <= fence_radius - 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 = stopping_point * ((fence_radius - margin_cm) / stopping_point_dist_from_home);
|
|
const Vector2f target_direction = target_offset - position_xy;
|
|
const float distance_to_target = target_direction.length();
|
|
if (is_positive(distance_to_target)) {
|
|
const float max_speed = get_max_speed(kP, accel_cmss, distance_to_target, dt);
|
|
desired_vel_cms = target_direction * (MIN(desired_speed,max_speed) / distance_to_target);
|
|
_last_limit_time = AP_HAL::millis();
|
|
}
|
|
} else {
|
|
// 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 = position_xy + desired_vel_cms*((2.0f + margin_cm + get_stopping_distance(kP, accel_cmss, desired_speed))/desired_speed);
|
|
const float stopping_point_plus_margin_dist_from_home = stopping_point_plus_margin.length();
|
|
if (dist_from_home >= fence_radius - 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 >= dist_from_home) {
|
|
desired_vel_cms.zero();
|
|
_last_limit_time = AP_HAL::millis();
|
|
}
|
|
} else {
|
|
// shorten vector without adjusting its direction
|
|
Vector2f intersection;
|
|
if (Vector2f::circle_segment_intersection(position_xy, stopping_point_plus_margin, Vector2f(0.0f,0.0f), fence_radius - margin_cm, intersection)) {
|
|
const float distance_to_target = (intersection - position_xy).length();
|
|
const float max_speed = get_max_speed(kP, accel_cmss, distance_to_target, dt);
|
|
if (max_speed < desired_speed) {
|
|
desired_vel_cms *= MAX(max_speed, 0.0f) / desired_speed;
|
|
_last_limit_time = AP_HAL::millis();
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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_cms, Vector2f &backup_vel, 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, quad_2_back_vel, quad_3_back_vel, quad_4_back_vel;
|
|
|
|
// 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;
|
|
// adjust velocity
|
|
adjust_velocity_polygon(kP, accel_cmss, desired_vel_cms, backup_vel_inc, boundary, num_points, true, fence->get_margin(), dt, true);
|
|
find_max_quadrant_velocity(backup_vel_inc, quad_1_back_vel, quad_2_back_vel, quad_3_back_vel, quad_4_back_vel);
|
|
}
|
|
|
|
// 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;
|
|
// adjust velocity
|
|
adjust_velocity_polygon(kP, accel_cmss, desired_vel_cms, backup_vel_exc, boundary, num_points, true, fence->get_margin(), dt, false);
|
|
find_max_quadrant_velocity(backup_vel_exc, quad_1_back_vel, quad_2_back_vel, quad_3_back_vel, quad_4_back_vel);
|
|
}
|
|
// desired backup velocity is sum of maximum velocity component in each quadrant
|
|
backup_vel = quad_1_back_vel + quad_2_back_vel + quad_3_back_vel + quad_4_back_vel;
|
|
}
|
|
|
|
/*
|
|
* Adjusts the desired velocity for the inclusion circles
|
|
*/
|
|
void AC_Avoid::adjust_velocity_inclusion_circles(float kP, float accel_cmss, Vector2f &desired_vel_cms, Vector2f &backup_vel, 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;
|
|
if (!AP::ahrs().get_relative_position_NE_origin(position_NE)) {
|
|
// do not limit velocity if we don't have a position estimate
|
|
return;
|
|
}
|
|
position_NE = position_NE * 100.0f; // m to cm
|
|
|
|
// get the margin to the fence in cm
|
|
const float margin_cm = fence->get_margin() * 100.0f;
|
|
|
|
// get desired speed
|
|
const float desired_speed = desired_vel_cms.length();
|
|
|
|
// get stopping distance as an offset from the vehicle
|
|
Vector2f stopping_offset;
|
|
if (!is_zero(desired_speed)) {
|
|
switch ((AC_Avoid::BehaviourType)_behavior.get()) {
|
|
case BEHAVIOR_SLIDE:
|
|
stopping_offset = desired_vel_cms*(get_stopping_distance(kP, accel_cmss, desired_speed)/desired_speed);
|
|
break;
|
|
case BEHAVIOR_STOP:
|
|
// calculate stopping point plus a margin so we look forward far enough to intersect with circular fence
|
|
stopping_offset = desired_vel_cms*((2.0f + margin_cm + get_stopping_distance(kP, accel_cmss, desired_speed))/desired_speed);
|
|
break;
|
|
}
|
|
}
|
|
|
|
// for backing away
|
|
Vector2f quad_1_back_vel, quad_2_back_vel, quad_3_back_vel, quad_4_back_vel;
|
|
|
|
// iterate through inclusion circles
|
|
for (uint8_t i = 0; i < num_circles; i++) {
|
|
Vector2f center_pos_cm;
|
|
float radius;
|
|
if (fence->polyfence().get_inclusion_circle(i, center_pos_cm, radius)) {
|
|
// get position relative to circle's center
|
|
const Vector2f position_NE_rel = (position_NE - center_pos_cm);
|
|
|
|
// if we are outside this circle do not limit velocity for this circle
|
|
const float dist_sq_cm = position_NE_rel.length_squared();
|
|
const float radius_cm = (radius * 100.0f);
|
|
if (dist_sq_cm > sq(radius_cm)) {
|
|
continue;
|
|
}
|
|
|
|
const float radius_with_margin = radius_cm - margin_cm;
|
|
if (is_negative(radius_with_margin)) {
|
|
return;
|
|
}
|
|
|
|
const float margin_breach = radius_with_margin - safe_sqrt(dist_sq_cm);
|
|
// back away if vehicle has breached margin
|
|
if (is_negative(margin_breach)) {
|
|
calc_backup_velocity(kP, accel_cmss, quad_1_back_vel, quad_2_back_vel, quad_3_back_vel, quad_4_back_vel, margin_breach, position_NE_rel, dt);
|
|
}
|
|
if (is_zero(desired_speed)) {
|
|
// no avoidance necessary when desired speed is zero
|
|
continue;
|
|
}
|
|
|
|
switch ((AC_Avoid::BehaviourType)_behavior.get()) {
|
|
case BEHAVIOR_SLIDE: {
|
|
// implement sliding behaviour
|
|
const Vector2f stopping_point = position_NE_rel + stopping_offset;
|
|
const float stopping_point_dist = stopping_point.length();
|
|
if (is_zero(stopping_point_dist) || (stopping_point_dist <= (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 = stopping_point * ((radius_cm - margin_cm) / stopping_point_dist);
|
|
const Vector2f target_direction = target_offset - position_NE_rel;
|
|
const float distance_to_target = target_direction.length();
|
|
if (is_positive(distance_to_target)) {
|
|
const float max_speed = get_max_speed(kP, accel_cmss, distance_to_target, dt);
|
|
desired_vel_cms = target_direction * (MIN(desired_speed,max_speed) / distance_to_target);
|
|
}
|
|
}
|
|
break;
|
|
case BEHAVIOR_STOP: {
|
|
// implement stopping behaviour
|
|
const Vector2f stopping_point_plus_margin = position_NE_rel + stopping_offset;
|
|
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.length() >= dist_cm) {
|
|
desired_vel_cms.zero();
|
|
// desired backup velocity is sum of maximum velocity component in each quadrant
|
|
backup_vel = quad_1_back_vel + quad_2_back_vel + quad_3_back_vel + quad_4_back_vel;
|
|
return;
|
|
}
|
|
} else {
|
|
// shorten vector without adjusting its direction
|
|
Vector2f intersection;
|
|
if (Vector2f::circle_segment_intersection(position_NE_rel, stopping_point_plus_margin, Vector2f(0.0f,0.0f), radius_cm - margin_cm, intersection)) {
|
|
const float distance_to_target = (intersection - position_NE_rel).length();
|
|
const float max_speed = get_max_speed(kP, accel_cmss, distance_to_target, dt);
|
|
if (max_speed < desired_speed) {
|
|
desired_vel_cms *= MAX(max_speed, 0.0f) / desired_speed;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
// desired backup velocity is sum of maximum velocity component in each quadrant
|
|
backup_vel = quad_1_back_vel + quad_2_back_vel + quad_3_back_vel + quad_4_back_vel;
|
|
}
|
|
|
|
/*
|
|
* Adjusts the desired velocity for the exclusion circles
|
|
*/
|
|
void AC_Avoid::adjust_velocity_exclusion_circles(float kP, float accel_cmss, Vector2f &desired_vel_cms, Vector2f &backup_vel, 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;
|
|
if (!AP::ahrs().get_relative_position_NE_origin(position_NE)) {
|
|
// do not limit velocity if we don't have a position estimate
|
|
return;
|
|
}
|
|
position_NE = position_NE * 100.0f; // m to cm
|
|
|
|
// get the margin to the fence in cm
|
|
const float margin_cm = fence->get_margin() * 100.0f;
|
|
|
|
// for backing away
|
|
Vector2f quad_1_back_vel, quad_2_back_vel, quad_3_back_vel, quad_4_back_vel;
|
|
|
|
// get desired speed
|
|
const float desired_speed = desired_vel_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;
|
|
if (!is_zero(desired_speed)) {
|
|
if ((AC_Avoid::BehaviourType)_behavior.get() == BEHAVIOR_STOP) {
|
|
stopping_offset = desired_vel_cms*((2.0f + margin_cm + get_stopping_distance(kP, accel_cmss, desired_speed))/desired_speed);
|
|
}
|
|
}
|
|
// iterate through exclusion circles
|
|
for (uint8_t i = 0; i < num_circles; i++) {
|
|
Vector2f center_pos_cm;
|
|
float radius;
|
|
if (fence->polyfence().get_exclusion_circle(i, center_pos_cm, radius)) {
|
|
// get position relative to circle's center
|
|
const Vector2f position_NE_rel = (position_NE - center_pos_cm);
|
|
|
|
// if we are inside this circle do not limit velocity for this circle
|
|
const float dist_sq_cm = position_NE_rel.length_squared();
|
|
const float radius_cm = (radius * 100.0f);
|
|
if (radius_cm < margin_cm) {
|
|
return;
|
|
}
|
|
if (dist_sq_cm < sq(radius_cm)) {
|
|
continue;
|
|
}
|
|
|
|
const Vector2f vector_to_center = center_pos_cm - position_NE;
|
|
const float dist_to_boundary = vector_to_center.length() - radius_cm;
|
|
// back away if vehicle has breached margin
|
|
if (is_negative(dist_to_boundary - margin_cm)) {
|
|
calc_backup_velocity(kP, accel_cmss, quad_1_back_vel, quad_2_back_vel, quad_3_back_vel, quad_4_back_vel, margin_cm - dist_to_boundary, vector_to_center, dt);
|
|
}
|
|
if (is_zero(desired_speed)) {
|
|
// no avoidance necessary when desired speed is zero
|
|
continue;
|
|
}
|
|
|
|
switch ((AC_Avoid::BehaviourType)_behavior.get()) {
|
|
case BEHAVIOR_SLIDE: {
|
|
// vector from current position to circle's center
|
|
Vector2f limit_direction = vector_to_center;
|
|
if (limit_direction.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.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.normalize();
|
|
limit_velocity(kP, accel_cmss, desired_vel_cms, limit_direction, MAX(limit_distance_cm - margin_cm, 0.0f), dt);
|
|
}
|
|
break;
|
|
case BEHAVIOR_STOP: {
|
|
// implement stopping behaviour
|
|
const Vector2f stopping_point_plus_margin = position_NE_rel + stopping_offset;
|
|
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.length() <= dist_cm) {
|
|
desired_vel_cms.zero();
|
|
backup_vel = quad_1_back_vel + quad_2_back_vel + quad_3_back_vel + quad_4_back_vel;
|
|
return;
|
|
}
|
|
} else {
|
|
// shorten vector without adjusting its direction
|
|
Vector2f intersection;
|
|
if (Vector2f::circle_segment_intersection(position_NE_rel, stopping_point_plus_margin, Vector2f(0.0f,0.0f), radius_cm + margin_cm, intersection)) {
|
|
const float distance_to_target = (intersection - position_NE_rel).length();
|
|
const float max_speed = get_max_speed(kP, accel_cmss, distance_to_target, dt);
|
|
if (max_speed < desired_speed) {
|
|
desired_vel_cms *= MAX(max_speed, 0.0f) / desired_speed;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
// desired backup velocity is sum of maximum velocity component in each quadrant
|
|
backup_vel = quad_1_back_vel + quad_2_back_vel + quad_3_back_vel + quad_4_back_vel;
|
|
}
|
|
|
|
/*
|
|
* Adjusts the desired velocity for the beacon fence.
|
|
*/
|
|
void AC_Avoid::adjust_velocity_beacon_fence(float kP, float accel_cmss, Vector2f &desired_vel_cms, Vector2f &backup_vel, 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 = 0;
|
|
if (AP::fence()) {
|
|
margin = AP::fence()->get_margin();
|
|
}
|
|
adjust_velocity_polygon(kP, accel_cmss, desired_vel_cms, backup_vel, boundary, num_points, true, margin, dt, true);
|
|
}
|
|
|
|
/*
|
|
* Adjusts the desired velocity based on output from the proximity sensor
|
|
*/
|
|
void AC_Avoid::adjust_velocity_proximity(float kP, float accel_cmss, Vector2f &desired_vel_cms, Vector2f &backup_vel, float dt)
|
|
{
|
|
// exit immediately if proximity sensor is not present
|
|
AP_Proximity *proximity = AP::proximity();
|
|
if (!proximity) {
|
|
return;
|
|
}
|
|
|
|
AP_Proximity &_proximity = *proximity;
|
|
|
|
if (_proximity.get_status() != AP_Proximity::Status::Good) {
|
|
return;
|
|
}
|
|
|
|
// get boundary from proximity sensor
|
|
uint16_t num_points = 0;
|
|
const Vector2f *boundary = _proximity.get_boundary_points(num_points);
|
|
adjust_velocity_polygon(kP, accel_cmss, desired_vel_cms, backup_vel, boundary, num_points, false, _margin, dt, true);
|
|
}
|
|
|
|
/*
|
|
* 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, const Vector2f* boundary, uint16_t num_points, bool earth_frame, 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_xy;
|
|
if (earth_frame) {
|
|
if (!_ahrs.get_relative_position_NE_origin(position_xy)) {
|
|
// boundary is in earth frame but we have no idea
|
|
// where we are
|
|
return;
|
|
}
|
|
position_xy = position_xy * 100.0f; // m to cm
|
|
}
|
|
|
|
// return if we have already breached polygon
|
|
const bool inside_polygon = !Polygon_outside(position_xy, 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(desired_vel_cms);
|
|
Vector2f desired_back_vel_cms;
|
|
|
|
// if boundary points are in body-frame, rotate velocity vector from earth frame to body-frame
|
|
if (!earth_frame) {
|
|
safe_vel.x = desired_vel_cms.y * _ahrs.sin_yaw() + desired_vel_cms.x * _ahrs.cos_yaw(); // right
|
|
safe_vel.y = desired_vel_cms.y * _ahrs.cos_yaw() - desired_vel_cms.x * _ahrs.sin_yaw(); // forward
|
|
}
|
|
|
|
// calc margin in cm
|
|
const float margin_cm = MAX(margin * 100.0f, 0.0f);
|
|
|
|
// for stopping
|
|
const float speed = safe_vel.length();
|
|
Vector2f stopping_point_plus_margin;
|
|
if (!desired_vel_cms.is_zero()) {
|
|
stopping_point_plus_margin = position_xy + safe_vel*((2.0f + margin_cm + get_stopping_distance(kP, accel_cmss, speed))/speed);
|
|
}
|
|
|
|
// for backing away
|
|
Vector2f quad_1_back_vel, quad_2_back_vel, quad_3_back_vel, quad_4_back_vel;
|
|
|
|
for (uint16_t i=0; i<num_points; i++) {
|
|
uint16_t j = i+1;
|
|
if (j >= num_points) {
|
|
j = 0;
|
|
}
|
|
// end points of current edge
|
|
Vector2f start = boundary[j];
|
|
Vector2f end = boundary[i];
|
|
Vector2f vector_to_boundary = Vector2f::closest_point(position_xy, start, end) - position_xy;
|
|
// back away if vehicle has breached margin
|
|
if (is_negative(vector_to_boundary.length() - margin_cm)) {
|
|
calc_backup_velocity(kP, accel_cmss, quad_1_back_vel, quad_2_back_vel, quad_3_back_vel, quad_4_back_vel, margin_cm-vector_to_boundary.length(), vector_to_boundary, dt);
|
|
}
|
|
|
|
// exit immediately if no desired velocity
|
|
if (desired_vel_cms.is_zero()) {
|
|
continue;
|
|
}
|
|
|
|
if ((AC_Avoid::BehaviourType)_behavior.get() == BEHAVIOR_SLIDE) {
|
|
// vector from current position to closest point on current edge
|
|
Vector2f limit_direction = vector_to_boundary;
|
|
// distance to closest point
|
|
const float limit_distance_cm = limit_direction.length();
|
|
if (!is_zero(limit_distance_cm)) {
|
|
// We are strictly inside the given edge.
|
|
// Adjust velocity to not violate this edge.
|
|
limit_direction /= limit_distance_cm;
|
|
limit_velocity(kP, accel_cmss, safe_vel, limit_direction, MAX(limit_distance_cm - margin_cm, 0.0f), dt);
|
|
} else {
|
|
// We are exactly on the edge - treat this as a fence breach.
|
|
// i.e. do not adjust velocity.
|
|
return;
|
|
}
|
|
} else {
|
|
// find intersection with line segment
|
|
Vector2f intersection;
|
|
if (Vector2f::segment_intersection(position_xy, stopping_point_plus_margin, start, end, intersection)) {
|
|
// vector from current position to point on current edge
|
|
Vector2f limit_direction = intersection - position_xy;
|
|
const float limit_distance_cm = limit_direction.length();
|
|
if (!is_zero(limit_distance_cm)) {
|
|
if (limit_distance_cm <= margin_cm) {
|
|
// we are within the margin so stop vehicle
|
|
safe_vel.zero();
|
|
} else {
|
|
// vehicle inside the given edge, adjust velocity to not violate this edge
|
|
limit_direction /= limit_distance_cm;
|
|
limit_velocity(kP, accel_cmss, safe_vel, limit_direction, MAX(limit_distance_cm - margin_cm, 0.0f), dt);
|
|
}
|
|
} else {
|
|
// We are exactly on the edge - treat this as a fence breach.
|
|
// i.e. do not adjust velocity.
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
// desired backup velocity is sum of maximum velocity component in each quadrant
|
|
desired_back_vel_cms = quad_1_back_vel + quad_2_back_vel + quad_3_back_vel + quad_4_back_vel;
|
|
|
|
// set modified desired velocity vector or back away velocity vector
|
|
if (earth_frame) {
|
|
desired_vel_cms = safe_vel;
|
|
backup_vel = desired_back_vel_cms;
|
|
} else {
|
|
// if points were in body-frame, rotate resulting vector back to earth-frame
|
|
desired_vel_cms.x = safe_vel.x * _ahrs.cos_yaw() - safe_vel.y * _ahrs.sin_yaw();
|
|
desired_vel_cms.y = safe_vel.x * _ahrs.sin_yaw() + safe_vel.y * _ahrs.cos_yaw();
|
|
backup_vel.x = desired_back_vel_cms.x * _ahrs.cos_yaw() - desired_back_vel_cms.y * _ahrs.sin_yaw();
|
|
backup_vel.y = desired_back_vel_cms.x * _ahrs.sin_yaw() + desired_back_vel_cms.y * _ahrs.cos_yaw();
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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);
|
|
}
|
|
}
|
|
|
|
// convert distance (in meters) to a lean percentage (in 0~1 range) for use in manual flight modes
|
|
float AC_Avoid::distance_to_lean_pct(float dist_m)
|
|
{
|
|
// ignore objects beyond DIST_MAX
|
|
if (dist_m < 0.0f || dist_m >= _dist_max || _dist_max <= 0.0f) {
|
|
return 0.0f;
|
|
}
|
|
// inverted but linear response
|
|
return 1.0f - (dist_m / _dist_max);
|
|
}
|
|
|
|
// 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_pct(float &roll_positive, float &roll_negative, float &pitch_positive, float &pitch_negative)
|
|
{
|
|
AP_Proximity *proximity = AP::proximity();
|
|
if (proximity == nullptr) {
|
|
return;
|
|
}
|
|
AP_Proximity &_proximity = *proximity;
|
|
|
|
// exit immediately if proximity sensor is not present
|
|
if (_proximity.get_status() != AP_Proximity::Status::Good) {
|
|
return;
|
|
}
|
|
|
|
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<obj_count; i++) {
|
|
float ang_deg, dist_m;
|
|
if (_proximity.get_object_angle_and_distance(i, ang_deg, dist_m)) {
|
|
if (dist_m < _dist_max) {
|
|
// convert distance to lean angle (in 0 to 1 range)
|
|
const float lean_pct = distance_to_lean_pct(dist_m);
|
|
// convert angle to roll and pitch lean percentages
|
|
const float angle_rad = radians(ang_deg);
|
|
const float roll_pct = -sinf(angle_rad) * lean_pct;
|
|
const float pitch_pct = cosf(angle_rad) * lean_pct;
|
|
// update roll, pitch maximums
|
|
if (roll_pct > 0.0f) {
|
|
roll_positive = MAX(roll_positive, roll_pct);
|
|
} else if (roll_pct < 0.0f) {
|
|
roll_negative = MIN(roll_negative, roll_pct);
|
|
}
|
|
if (pitch_pct > 0.0f) {
|
|
pitch_positive = MAX(pitch_positive, pitch_pct);
|
|
} else if (pitch_pct < 0.0f) {
|
|
pitch_negative = MIN(pitch_negative, pitch_pct);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// singleton instance
|
|
AC_Avoid *AC_Avoid::_singleton;
|
|
|
|
namespace AP {
|
|
|
|
AC_Avoid *ac_avoid()
|
|
{
|
|
return AC_Avoid::get_singleton();
|
|
}
|
|
|
|
}
|