mirror of https://github.com/ArduPilot/ardupilot
81 lines
3.1 KiB
C++
81 lines
3.1 KiB
C++
#include "Rover.h"
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bool ModeLoiter::_enter()
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{
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// set _destination to reasonable stopping point
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if (!g2.wp_nav.get_stopping_location(_destination)) {
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return false;
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}
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// initialise desired speed to current speed
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if (!attitude_control.get_forward_speed(_desired_speed)) {
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_desired_speed = 0.0f;
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}
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// initialise heading to current heading
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_desired_yaw_cd = ahrs.yaw_sensor;
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return true;
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}
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void ModeLoiter::update()
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{
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// get distance (in meters) to destination
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_distance_to_destination = rover.current_loc.get_distance(_destination);
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const float loiter_radius = g2.sailboat.tack_enabled() ? g2.sailboat.get_loiter_radius() : g2.loit_radius;
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// if within loiter radius slew desired speed towards zero and use existing desired heading
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if (_distance_to_destination <= loiter_radius) {
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// sailboats should not stop unless motoring
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const float desired_speed_within_radius = g2.sailboat.tack_enabled() ? 0.1f : 0.0f;
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_desired_speed = attitude_control.get_desired_speed_accel_limited(desired_speed_within_radius, rover.G_Dt);
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// if we have a sail but not trying to use it then point into the wind
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if (!g2.sailboat.tack_enabled() && g2.sailboat.sail_enabled()) {
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_desired_yaw_cd = degrees(g2.windvane.get_true_wind_direction_rad()) * 100.0f;
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}
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} else {
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// P controller with hard-coded gain to convert distance to desired speed
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_desired_speed = MIN((_distance_to_destination - loiter_radius) * g2.loiter_speed_gain, g2.wp_nav.get_default_speed());
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// calculate bearing to destination
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_desired_yaw_cd = rover.current_loc.get_bearing_to(_destination);
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float yaw_error_cd = wrap_180_cd(_desired_yaw_cd - ahrs.yaw_sensor);
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// if destination is behind vehicle, reverse towards it
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if ((fabsf(yaw_error_cd) > 9000 && g2.loit_type == 0) || g2.loit_type == 2) {
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_desired_yaw_cd = wrap_180_cd(_desired_yaw_cd + 18000);
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yaw_error_cd = wrap_180_cd(_desired_yaw_cd - ahrs.yaw_sensor);
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_desired_speed = -_desired_speed;
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}
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// reduce desired speed if yaw_error is large
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// 45deg of error reduces speed to 75%, 90deg of error reduces speed to 50%
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float yaw_error_ratio = 1.0f - constrain_float(fabsf(yaw_error_cd / 9000.0f), 0.0f, 1.0f) * 0.5f;
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_desired_speed *= yaw_error_ratio;
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}
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// 0 turn rate is no limit
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float turn_rate = 0.0;
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// make sure sailboats don't try and sail directly into the wind
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if (g2.sailboat.use_indirect_route(_desired_yaw_cd)) {
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_desired_yaw_cd = g2.sailboat.calc_heading(_desired_yaw_cd);
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if (g2.sailboat.tacking()) {
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// use pivot turn rate for tacks
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turn_rate = g2.wp_nav.get_pivot_rate();
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}
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}
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// run steering and throttle controllers
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calc_steering_to_heading(_desired_yaw_cd, turn_rate);
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calc_throttle(_desired_speed, true);
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}
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// get desired location
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bool ModeLoiter::get_desired_location(Location& destination) const
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{
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destination = _destination;
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return true;
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}
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