ardupilot/ArduCopter/mode_follow.cpp

176 lines
7.4 KiB
C++

#include "Copter.h"
#if MODE_FOLLOW_ENABLED == ENABLED
/*
* mode_follow.cpp - follow another mavlink-enabled vehicle by system id
*
* TODO: stick control to move around on sphere
* TODO: stick control to change sphere diameter
* TODO: "channel 7 option" to lock onto "pointed at" target
* TODO: do better in terms of loitering around the moving point; may need a PID? Maybe use loiter controller somehow?
* TODO: extrapolate target vehicle position using its velocity and acceleration
* TODO: ensure AC_AVOID_ENABLED is true because we rely on it velocity limiting functions
*/
// initialise follow mode
bool Copter::ModeFollow::init(const bool ignore_checks)
{
if (!g2.follow.enabled()) {
gcs().send_text(MAV_SEVERITY_WARNING, "Set FOLL_ENABLE = 1");
return false;
}
// re-use guided mode
return Copter::ModeGuided::init(ignore_checks);
}
void Copter::ModeFollow::run()
{
// if not auto armed or motor interlock not enabled set throttle to zero and exit immediately
if (!motors->armed() || !ap.auto_armed || !motors->get_interlock()) {
zero_throttle_and_relax_ac();
return;
}
// re-use guided mode's velocity controller
// Note: this is safe from interference from GCSs and companion computer's whose guided mode
// position and velocity requests will be ignored while the vehicle is not in guided mode
// variables to be sent to velocity controller
Vector3f desired_velocity_neu_cms;
bool use_yaw = false;
float yaw_cd = 0.0f;
Vector3f dist_vec; // vector to lead vehicle
Vector3f dist_vec_offs; // vector to lead vehicle + offset
Vector3f vel_of_target; // velocity of lead vehicle
if (g2.follow.get_target_dist_and_vel_ned(dist_vec, dist_vec_offs, vel_of_target)) {
// convert dist_vec_offs to cm in NEU
const Vector3f dist_vec_offs_neu(dist_vec_offs.x * 100.0f, dist_vec_offs.y * 100.0f, -dist_vec_offs.z * 100.0f);
// calculate desired velocity vector in cm/s in NEU
const float kp = g2.follow.get_pos_p().kP();
desired_velocity_neu_cms.x = (vel_of_target.x * 100.0f) + (dist_vec_offs_neu.x * kp);
desired_velocity_neu_cms.y = (vel_of_target.y * 100.0f) + (dist_vec_offs_neu.y * kp);
desired_velocity_neu_cms.z = (-vel_of_target.z * 100.0f) + (dist_vec_offs_neu.z * kp);
// scale desired velocity to stay within horizontal speed limit
float desired_speed_xy = safe_sqrt(sq(desired_velocity_neu_cms.x) + sq(desired_velocity_neu_cms.y));
if (!is_zero(desired_speed_xy) && (desired_speed_xy > pos_control->get_max_speed_xy())) {
const float scalar_xy = pos_control->get_max_speed_xy() / desired_speed_xy;
desired_velocity_neu_cms.x *= scalar_xy;
desired_velocity_neu_cms.y *= scalar_xy;
desired_speed_xy = pos_control->get_max_speed_xy();
}
// limit desired velocity to be between maximum climb and descent rates
desired_velocity_neu_cms.z = constrain_float(desired_velocity_neu_cms.z, -fabsf(pos_control->get_max_speed_down()), pos_control->get_max_speed_up());
// unit vector towards target position (i.e. vector to lead vehicle + offset)
Vector3f dir_to_target_neu = dist_vec_offs_neu;
const float dir_to_target_neu_len = dir_to_target_neu.length();
if (!is_zero(dir_to_target_neu_len)) {
dir_to_target_neu /= dir_to_target_neu_len;
}
// create horizontal desired velocity vector (required for slow down calculations)
Vector2f desired_velocity_xy_cms(desired_velocity_neu_cms.x, desired_velocity_neu_cms.y);
// create horizontal unit vector towards target (required for slow down calculations)
Vector2f dir_to_target_xy(desired_velocity_xy_cms.x, desired_velocity_xy_cms.y);
if (!dir_to_target_xy.is_zero()) {
dir_to_target_xy.normalize();
}
// slow down horizontally as we approach target (use 1/2 of maximum deceleration for gentle slow down)
const float dist_to_target_xy = Vector2f(dist_vec_offs_neu.x, dist_vec_offs_neu.y).length();
copter.avoid.limit_velocity(pos_control->get_pos_xy_p().kP().get(), pos_control->get_max_accel_xy() * 0.5f, desired_velocity_xy_cms, dir_to_target_xy, dist_to_target_xy, copter.G_Dt);
// limit the horizontal velocity to prevent fence violations
copter.avoid.adjust_velocity(pos_control->get_pos_xy_p().kP().get(), pos_control->get_max_accel_xy(), desired_velocity_xy_cms, G_Dt);
// copy horizontal velocity limits back to 3d vector
desired_velocity_neu_cms.x = desired_velocity_xy_cms.x;
desired_velocity_neu_cms.y = desired_velocity_xy_cms.y;
// limit vertical desired_velocity_neu_cms to slow as we approach target (we use 1/2 of maximum deceleration for gentle slow down)
const float des_vel_z_max = copter.avoid.get_max_speed(pos_control->get_pos_z_p().kP().get(), pos_control->get_max_accel_z() * 0.5f, fabsf(dist_vec_offs_neu.z), copter.G_Dt);
desired_velocity_neu_cms.z = constrain_float(desired_velocity_neu_cms.z, -des_vel_z_max, des_vel_z_max);
// get avoidance adjusted climb rate
desired_velocity_neu_cms.z = get_avoidance_adjusted_climbrate(desired_velocity_neu_cms.z);
// calculate vehicle heading
switch (g2.follow.get_yaw_behave()) {
case AP_Follow::YAW_BEHAVE_FACE_LEAD_VEHICLE: {
const Vector3f dist_vec_xy(dist_vec.x, dist_vec.y, 0.0f);
if (dist_vec_xy.length() > 1.0f) {
yaw_cd = get_bearing_cd(Vector3f(), dist_vec_xy);
use_yaw = true;
}
break;
}
case AP_Follow::YAW_BEHAVE_SAME_AS_LEAD_VEHICLE: {
float target_hdg = 0.0f;
if (g2.follow.get_target_heading(target_hdg)) {
yaw_cd = target_hdg * 100.0f;
use_yaw = true;
}
break;
}
case AP_Follow::YAW_BEHAVE_DIR_OF_FLIGHT: {
const Vector3f vel_vec(desired_velocity_neu_cms.x, desired_velocity_neu_cms.y, 0.0f);
if (vel_vec.length() > 100.0f) {
yaw_cd = get_bearing_cd(Vector3f(), vel_vec);
use_yaw = true;
}
break;
}
case AP_Follow::YAW_BEHAVE_NONE:
default:
// do nothing
break;
}
}
// log output at 10hz
uint32_t now = AP_HAL::millis();
bool log_request = false;
if ((now - last_log_ms >= 100) || (last_log_ms == 0)) {
log_request = true;
last_log_ms = now;
}
// re-use guided mode's velocity controller (takes NEU)
Copter::ModeGuided::set_velocity(desired_velocity_neu_cms, use_yaw, yaw_cd, false, 0.0f, false, log_request);
Copter::ModeGuided::run();
}
uint32_t Copter::ModeFollow::wp_distance() const
{
return g2.follow.get_distance_to_target() * 100;
}
int32_t Copter::ModeFollow::wp_bearing() const
{
return g2.follow.get_bearing_to_target() * 100;
}
/*
get target position for mavlink reporting
*/
bool Copter::ModeFollow::get_wp(Location &loc)
{
float dist = g2.follow.get_distance_to_target();
float bearing = g2.follow.get_bearing_to_target();
loc = copter.current_loc;
location_update(loc, bearing, dist);
return true;
}
#endif // MODE_FOLLOW_ENABLED == ENABLED