mirror of
https://gitee.com/mirrors_PX4/PX4-Autopilot.git
synced 2026-10-15 21:43:33 +08:00
Initial import
This commit is contained in:
Lorenz Meier
@@ -0,0 +1,372 @@
|
||||
/****************************************************************************
|
||||
*
|
||||
* Copyright (c) 2013 Estimation and Control Library (ECL). All rights reserved.
|
||||
*
|
||||
* Redistribution and use in source and binary forms, with or without
|
||||
* modification, are permitted provided that the following conditions
|
||||
* are met:
|
||||
*
|
||||
* 1. Redistributions of source code must retain the above copyright
|
||||
* notice, this list of conditions and the following disclaimer.
|
||||
* 2. Redistributions in binary form must reproduce the above copyright
|
||||
* notice, this list of conditions and the following disclaimer in
|
||||
* the documentation and/or other materials provided with the
|
||||
* distribution.
|
||||
* 3. Neither the name ECL nor the names of its contributors may be
|
||||
* used to endorse or promote products derived from this software
|
||||
* without specific prior written permission.
|
||||
*
|
||||
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
||||
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
||||
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
|
||||
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
|
||||
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
|
||||
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
|
||||
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
|
||||
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
|
||||
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
||||
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
|
||||
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
||||
* POSSIBILITY OF SUCH DAMAGE.
|
||||
*
|
||||
****************************************************************************/
|
||||
|
||||
/**
|
||||
* @file ecl_l1_pos_controller.h
|
||||
* Implementation of L1 position control.
|
||||
* Authors and acknowledgements in header.
|
||||
*
|
||||
*/
|
||||
|
||||
#include <float.h>
|
||||
|
||||
#include "ecl_l1_pos_controller.h"
|
||||
|
||||
float ECL_L1_Pos_Controller::nav_roll()
|
||||
{
|
||||
float ret = atanf(_lateral_accel * 1.0f / CONSTANTS_ONE_G);
|
||||
ret = math::constrain(ret, -_roll_lim_rad, _roll_lim_rad);
|
||||
return ret;
|
||||
}
|
||||
|
||||
float ECL_L1_Pos_Controller::nav_lateral_acceleration_demand()
|
||||
{
|
||||
return _lateral_accel;
|
||||
}
|
||||
|
||||
float ECL_L1_Pos_Controller::nav_bearing()
|
||||
{
|
||||
return _wrap_pi(_nav_bearing);
|
||||
}
|
||||
|
||||
float ECL_L1_Pos_Controller::bearing_error()
|
||||
{
|
||||
return _bearing_error;
|
||||
}
|
||||
|
||||
float ECL_L1_Pos_Controller::target_bearing()
|
||||
{
|
||||
return _target_bearing;
|
||||
}
|
||||
|
||||
float ECL_L1_Pos_Controller::switch_distance(float wp_radius)
|
||||
{
|
||||
/* following [2], switching on L1 distance */
|
||||
return math::min(wp_radius, _L1_distance);
|
||||
}
|
||||
|
||||
bool ECL_L1_Pos_Controller::reached_loiter_target(void)
|
||||
{
|
||||
return _circle_mode;
|
||||
}
|
||||
|
||||
float ECL_L1_Pos_Controller::crosstrack_error(void)
|
||||
{
|
||||
return _crosstrack_error;
|
||||
}
|
||||
|
||||
void ECL_L1_Pos_Controller::navigate_waypoints(const math::Vector<2> &vector_A, const math::Vector<2> &vector_B, const math::Vector<2> &vector_curr_position,
|
||||
const math::Vector<2> &ground_speed_vector)
|
||||
{
|
||||
|
||||
/* this follows the logic presented in [1] */
|
||||
|
||||
float eta;
|
||||
float xtrack_vel;
|
||||
float ltrack_vel;
|
||||
|
||||
/* get the direction between the last (visited) and next waypoint */
|
||||
_target_bearing = get_bearing_to_next_waypoint(vector_curr_position(0), vector_curr_position(1), vector_B(0), vector_B(1));
|
||||
|
||||
/* enforce a minimum ground speed of 0.1 m/s to avoid singularities */
|
||||
float ground_speed = math::max(ground_speed_vector.length(), 0.1f);
|
||||
|
||||
/* calculate the L1 length required for the desired period */
|
||||
_L1_distance = _L1_ratio * ground_speed;
|
||||
|
||||
/* calculate vector from A to B */
|
||||
math::Vector<2> vector_AB = get_local_planar_vector(vector_A, vector_B);
|
||||
|
||||
/*
|
||||
* check if waypoints are on top of each other. If yes,
|
||||
* skip A and directly continue to B
|
||||
*/
|
||||
if (vector_AB.length() < 1.0e-6f) {
|
||||
vector_AB = get_local_planar_vector(vector_curr_position, vector_B);
|
||||
}
|
||||
|
||||
vector_AB.normalize();
|
||||
|
||||
/* calculate the vector from waypoint A to the aircraft */
|
||||
math::Vector<2> vector_A_to_airplane = get_local_planar_vector(vector_A, vector_curr_position);
|
||||
|
||||
/* calculate crosstrack error (output only) */
|
||||
_crosstrack_error = vector_AB % vector_A_to_airplane;
|
||||
|
||||
/*
|
||||
* If the current position is in a +-135 degree angle behind waypoint A
|
||||
* and further away from A than the L1 distance, then A becomes the L1 point.
|
||||
* If the aircraft is already between A and B normal L1 logic is applied.
|
||||
*/
|
||||
float distance_A_to_airplane = vector_A_to_airplane.length();
|
||||
float alongTrackDist = vector_A_to_airplane * vector_AB;
|
||||
|
||||
/* estimate airplane position WRT to B */
|
||||
math::Vector<2> vector_B_to_P_unit = get_local_planar_vector(vector_B, vector_curr_position).normalized();
|
||||
|
||||
/* calculate angle of airplane position vector relative to line) */
|
||||
|
||||
// XXX this could probably also be based solely on the dot product
|
||||
float AB_to_BP_bearing = atan2f(vector_B_to_P_unit % vector_AB, vector_B_to_P_unit * vector_AB);
|
||||
|
||||
/* extension from [2], fly directly to A */
|
||||
if (distance_A_to_airplane > _L1_distance && alongTrackDist / math::max(distance_A_to_airplane , 1.0f) < -0.7071f) {
|
||||
|
||||
/* calculate eta to fly to waypoint A */
|
||||
|
||||
/* unit vector from waypoint A to current position */
|
||||
math::Vector<2> vector_A_to_airplane_unit = vector_A_to_airplane.normalized();
|
||||
/* velocity across / orthogonal to line */
|
||||
xtrack_vel = ground_speed_vector % (-vector_A_to_airplane_unit);
|
||||
/* velocity along line */
|
||||
ltrack_vel = ground_speed_vector * (-vector_A_to_airplane_unit);
|
||||
eta = atan2f(xtrack_vel, ltrack_vel);
|
||||
/* bearing from current position to L1 point */
|
||||
_nav_bearing = atan2f(-vector_A_to_airplane_unit(1) , -vector_A_to_airplane_unit(0));
|
||||
|
||||
/*
|
||||
* If the AB vector and the vector from B to airplane point in the same
|
||||
* direction, we have missed the waypoint. At +- 90 degrees we are just passing it.
|
||||
*/
|
||||
} else if (fabsf(AB_to_BP_bearing) < math::radians(100.0f)) {
|
||||
/*
|
||||
* Extension, fly back to waypoint.
|
||||
*
|
||||
* This corner case is possible if the system was following
|
||||
* the AB line from waypoint A to waypoint B, then is
|
||||
* switched to manual mode (or otherwise misses the waypoint)
|
||||
* and behind the waypoint continues to follow the AB line.
|
||||
*/
|
||||
|
||||
/* calculate eta to fly to waypoint B */
|
||||
|
||||
/* velocity across / orthogonal to line */
|
||||
xtrack_vel = ground_speed_vector % (-vector_B_to_P_unit);
|
||||
/* velocity along line */
|
||||
ltrack_vel = ground_speed_vector * (-vector_B_to_P_unit);
|
||||
eta = atan2f(xtrack_vel, ltrack_vel);
|
||||
/* bearing from current position to L1 point */
|
||||
_nav_bearing = atan2f(-vector_B_to_P_unit(1) , -vector_B_to_P_unit(0));
|
||||
|
||||
} else {
|
||||
|
||||
/* calculate eta to fly along the line between A and B */
|
||||
|
||||
/* velocity across / orthogonal to line */
|
||||
xtrack_vel = ground_speed_vector % vector_AB;
|
||||
/* velocity along line */
|
||||
ltrack_vel = ground_speed_vector * vector_AB;
|
||||
/* calculate eta2 (angle of velocity vector relative to line) */
|
||||
float eta2 = atan2f(xtrack_vel, ltrack_vel);
|
||||
/* calculate eta1 (angle to L1 point) */
|
||||
float xtrackErr = vector_A_to_airplane % vector_AB;
|
||||
float sine_eta1 = xtrackErr / math::max(_L1_distance , 0.1f);
|
||||
/* limit output to 45 degrees */
|
||||
sine_eta1 = math::constrain(sine_eta1, -0.7071f, 0.7071f); //sin(pi/4) = 0.7071
|
||||
float eta1 = asinf(sine_eta1);
|
||||
eta = eta1 + eta2;
|
||||
/* bearing from current position to L1 point */
|
||||
_nav_bearing = atan2f(vector_AB(1), vector_AB(0)) + eta1;
|
||||
|
||||
}
|
||||
|
||||
/* limit angle to +-90 degrees */
|
||||
eta = math::constrain(eta, (-M_PI_F) / 2.0f, +M_PI_F / 2.0f);
|
||||
_lateral_accel = _K_L1 * ground_speed * ground_speed / _L1_distance * sinf(eta);
|
||||
|
||||
/* flying to waypoints, not circling them */
|
||||
_circle_mode = false;
|
||||
|
||||
/* the bearing angle, in NED frame */
|
||||
_bearing_error = eta;
|
||||
}
|
||||
|
||||
void ECL_L1_Pos_Controller::navigate_loiter(const math::Vector<2> &vector_A, const math::Vector<2> &vector_curr_position, float radius, int8_t loiter_direction,
|
||||
const math::Vector<2> &ground_speed_vector)
|
||||
{
|
||||
/* the complete guidance logic in this section was proposed by [2] */
|
||||
|
||||
/* calculate the gains for the PD loop (circle tracking) */
|
||||
float omega = (2.0f * M_PI_F / _L1_period);
|
||||
float K_crosstrack = omega * omega;
|
||||
float K_velocity = 2.0f * _L1_damping * omega;
|
||||
|
||||
/* update bearing to next waypoint */
|
||||
_target_bearing = get_bearing_to_next_waypoint(vector_curr_position(0), vector_curr_position(1), vector_A(0), vector_A(1));
|
||||
|
||||
/* ground speed, enforce minimum of 0.1 m/s to avoid singularities */
|
||||
float ground_speed = math::max(ground_speed_vector.length() , 0.1f);
|
||||
|
||||
/* calculate the L1 length required for the desired period */
|
||||
_L1_distance = _L1_ratio * ground_speed;
|
||||
|
||||
/* calculate the vector from waypoint A to current position */
|
||||
math::Vector<2> vector_A_to_airplane = get_local_planar_vector(vector_A, vector_curr_position);
|
||||
|
||||
math::Vector<2> vector_A_to_airplane_unit;
|
||||
|
||||
/* prevent NaN when normalizing */
|
||||
if (vector_A_to_airplane.length() > FLT_EPSILON) {
|
||||
/* store the normalized vector from waypoint A to current position */
|
||||
vector_A_to_airplane_unit = vector_A_to_airplane.normalized();
|
||||
} else {
|
||||
vector_A_to_airplane_unit = vector_A_to_airplane;
|
||||
}
|
||||
|
||||
/* calculate eta angle towards the loiter center */
|
||||
|
||||
/* velocity across / orthogonal to line from waypoint to current position */
|
||||
float xtrack_vel_center = vector_A_to_airplane_unit % ground_speed_vector;
|
||||
/* velocity along line from waypoint to current position */
|
||||
float ltrack_vel_center = - (ground_speed_vector * vector_A_to_airplane_unit);
|
||||
float eta = atan2f(xtrack_vel_center, ltrack_vel_center);
|
||||
/* limit eta to 90 degrees */
|
||||
eta = math::constrain(eta, -M_PI_F / 2.0f, +M_PI_F / 2.0f);
|
||||
|
||||
/* calculate the lateral acceleration to capture the center point */
|
||||
float lateral_accel_sp_center = _K_L1 * ground_speed * ground_speed / _L1_distance * sinf(eta);
|
||||
|
||||
/* for PD control: Calculate radial position and velocity errors */
|
||||
|
||||
/* radial velocity error */
|
||||
float xtrack_vel_circle = -ltrack_vel_center;
|
||||
/* radial distance from the loiter circle (not center) */
|
||||
float xtrack_err_circle = vector_A_to_airplane.length() - radius;
|
||||
|
||||
/* cross track error for feedback */
|
||||
_crosstrack_error = xtrack_err_circle;
|
||||
|
||||
/* calculate PD update to circle waypoint */
|
||||
float lateral_accel_sp_circle_pd = (xtrack_err_circle * K_crosstrack + xtrack_vel_circle * K_velocity);
|
||||
|
||||
/* calculate velocity on circle / along tangent */
|
||||
float tangent_vel = xtrack_vel_center * loiter_direction;
|
||||
|
||||
/* prevent PD output from turning the wrong way */
|
||||
if (tangent_vel < 0.0f) {
|
||||
lateral_accel_sp_circle_pd = math::max(lateral_accel_sp_circle_pd , 0.0f);
|
||||
}
|
||||
|
||||
/* calculate centripetal acceleration setpoint */
|
||||
float lateral_accel_sp_circle_centripetal = tangent_vel * tangent_vel / math::max((0.5f * radius) , (radius + xtrack_err_circle));
|
||||
|
||||
/* add PD control on circle and centripetal acceleration for total circle command */
|
||||
float lateral_accel_sp_circle = loiter_direction * (lateral_accel_sp_circle_pd + lateral_accel_sp_circle_centripetal);
|
||||
|
||||
/*
|
||||
* Switch between circle (loiter) and capture (towards waypoint center) mode when
|
||||
* the commands switch over. Only fly towards waypoint if outside the circle.
|
||||
*/
|
||||
|
||||
// XXX check switch over
|
||||
if ((lateral_accel_sp_center < lateral_accel_sp_circle && loiter_direction > 0 && xtrack_err_circle > 0.0f) ||
|
||||
(lateral_accel_sp_center > lateral_accel_sp_circle && loiter_direction < 0 && xtrack_err_circle > 0.0f)) {
|
||||
_lateral_accel = lateral_accel_sp_center;
|
||||
_circle_mode = false;
|
||||
/* angle between requested and current velocity vector */
|
||||
_bearing_error = eta;
|
||||
/* bearing from current position to L1 point */
|
||||
_nav_bearing = atan2f(-vector_A_to_airplane_unit(1) , -vector_A_to_airplane_unit(0));
|
||||
|
||||
} else {
|
||||
_lateral_accel = lateral_accel_sp_circle;
|
||||
_circle_mode = true;
|
||||
_bearing_error = 0.0f;
|
||||
/* bearing from current position to L1 point */
|
||||
_nav_bearing = atan2f(-vector_A_to_airplane_unit(1) , -vector_A_to_airplane_unit(0));
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
void ECL_L1_Pos_Controller::navigate_heading(float navigation_heading, float current_heading, const math::Vector<2> &ground_speed_vector)
|
||||
{
|
||||
/* the complete guidance logic in this section was proposed by [2] */
|
||||
|
||||
float eta;
|
||||
|
||||
/*
|
||||
* As the commanded heading is the only reference
|
||||
* (and no crosstrack correction occurs),
|
||||
* target and navigation bearing become the same
|
||||
*/
|
||||
_target_bearing = _nav_bearing = _wrap_pi(navigation_heading);
|
||||
eta = _target_bearing - _wrap_pi(current_heading);
|
||||
eta = _wrap_pi(eta);
|
||||
|
||||
/* consequently the bearing error is exactly eta: */
|
||||
_bearing_error = eta;
|
||||
|
||||
/* ground speed is the length of the ground speed vector */
|
||||
float ground_speed = ground_speed_vector.length();
|
||||
|
||||
/* adjust L1 distance to keep constant frequency */
|
||||
_L1_distance = ground_speed / _heading_omega;
|
||||
float omega_vel = ground_speed * _heading_omega;
|
||||
|
||||
/* not circling a waypoint */
|
||||
_circle_mode = false;
|
||||
|
||||
/* navigating heading means by definition no crosstrack error */
|
||||
_crosstrack_error = 0;
|
||||
|
||||
/* limit eta to 90 degrees */
|
||||
eta = math::constrain(eta, (-M_PI_F) / 2.0f, +M_PI_F / 2.0f);
|
||||
_lateral_accel = 2.0f * sinf(eta) * omega_vel;
|
||||
}
|
||||
|
||||
void ECL_L1_Pos_Controller::navigate_level_flight(float current_heading)
|
||||
{
|
||||
/* the logic in this section is trivial, but originally proposed by [2] */
|
||||
|
||||
/* reset all heading / error measures resulting in zero roll */
|
||||
_target_bearing = current_heading;
|
||||
_nav_bearing = current_heading;
|
||||
_bearing_error = 0;
|
||||
_crosstrack_error = 0;
|
||||
_lateral_accel = 0;
|
||||
|
||||
/* not circling a waypoint when flying level */
|
||||
_circle_mode = false;
|
||||
|
||||
}
|
||||
|
||||
|
||||
math::Vector<2> ECL_L1_Pos_Controller::get_local_planar_vector(const math::Vector<2> &origin, const math::Vector<2> &target) const
|
||||
{
|
||||
/* this is an approximation for small angles, proposed by [2] */
|
||||
|
||||
math::Vector<2> out(math::radians((target(0) - origin(0))), math::radians((target(1) - origin(1))*cosf(math::radians(origin(0)))));
|
||||
|
||||
return out * static_cast<float>(CONSTANTS_RADIUS_OF_EARTH);
|
||||
}
|
||||
|
||||
@@ -0,0 +1,268 @@
|
||||
/****************************************************************************
|
||||
*
|
||||
* Copyright (c) 2013 Estimation and Control Library (ECL). All rights reserved.
|
||||
*
|
||||
* Redistribution and use in source and binary forms, with or without
|
||||
* modification, are permitted provided that the following conditions
|
||||
* are met:
|
||||
*
|
||||
* 1. Redistributions of source code must retain the above copyright
|
||||
* notice, this list of conditions and the following disclaimer.
|
||||
* 2. Redistributions in binary form must reproduce the above copyright
|
||||
* notice, this list of conditions and the following disclaimer in
|
||||
* the documentation and/or other materials provided with the
|
||||
* distribution.
|
||||
* 3. Neither the name ECL nor the names of its contributors may be
|
||||
* used to endorse or promote products derived from this software
|
||||
* without specific prior written permission.
|
||||
*
|
||||
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
||||
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
||||
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
|
||||
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
|
||||
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
|
||||
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
|
||||
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
|
||||
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
|
||||
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
||||
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
|
||||
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
||||
* POSSIBILITY OF SUCH DAMAGE.
|
||||
*
|
||||
****************************************************************************/
|
||||
|
||||
/**
|
||||
* @file ecl_l1_pos_control.h
|
||||
* Implementation of L1 position control.
|
||||
*
|
||||
*
|
||||
* Acknowledgements and References:
|
||||
*
|
||||
* This implementation has been built for PX4 based on the original
|
||||
* publication from [1] and does include a lot of the ideas (not code)
|
||||
* from [2].
|
||||
*
|
||||
*
|
||||
* [1] S. Park, J. Deyst, and J. P. How, "A New Nonlinear Guidance Logic for Trajectory Tracking,"
|
||||
* Proceedings of the AIAA Guidance, Navigation and Control
|
||||
* Conference, Aug 2004. AIAA-2004-4900.
|
||||
*
|
||||
* [2] Paul Riseborough, Brandon Jones and Andrew Tridgell, L1 control for APM. Aug 2013.
|
||||
* - Explicit control over frequency and damping
|
||||
* - Explicit control over track capture angle
|
||||
* - Ability to use loiter radius smaller than L1 length
|
||||
* - Modified to use PD control for circle tracking to enable loiter radius less than L1 length
|
||||
* - Modified to enable period and damping of guidance loop to be set explicitly
|
||||
* - Modified to provide explicit control over capture angle
|
||||
*
|
||||
*/
|
||||
|
||||
#ifndef ECL_L1_POS_CONTROLLER_H
|
||||
#define ECL_L1_POS_CONTROLLER_H
|
||||
|
||||
#include <mathlib/mathlib.h>
|
||||
#include <geo/geo.h>
|
||||
#include <ecl/ecl.h>
|
||||
|
||||
/**
|
||||
* L1 Nonlinear Guidance Logic
|
||||
*/
|
||||
class __EXPORT ECL_L1_Pos_Controller
|
||||
{
|
||||
public:
|
||||
ECL_L1_Pos_Controller() {
|
||||
_L1_period = 25;
|
||||
_L1_damping = 0.75f;
|
||||
}
|
||||
|
||||
/**
|
||||
* The current target bearing
|
||||
*
|
||||
* @return bearing angle (-pi..pi, in NED frame)
|
||||
*/
|
||||
float nav_bearing();
|
||||
|
||||
|
||||
/**
|
||||
* Get lateral acceleration demand.
|
||||
*
|
||||
* @return Lateral acceleration in m/s^2
|
||||
*/
|
||||
float nav_lateral_acceleration_demand();
|
||||
|
||||
|
||||
/**
|
||||
* Heading error.
|
||||
*
|
||||
* The heading error is either compared to the current track
|
||||
* or to the tangent of the current loiter radius.
|
||||
*/
|
||||
float bearing_error();
|
||||
|
||||
|
||||
/**
|
||||
* Bearing from aircraft to current target.
|
||||
*
|
||||
* @return bearing angle (-pi..pi, in NED frame)
|
||||
*/
|
||||
float target_bearing();
|
||||
|
||||
|
||||
/**
|
||||
* Get roll angle setpoint for fixed wing.
|
||||
*
|
||||
* @return Roll angle (in NED frame)
|
||||
*/
|
||||
float nav_roll();
|
||||
|
||||
|
||||
/**
|
||||
* Get the current crosstrack error.
|
||||
*
|
||||
* @return Crosstrack error in meters.
|
||||
*/
|
||||
float crosstrack_error();
|
||||
|
||||
|
||||
/**
|
||||
* Returns true if the loiter waypoint has been reached
|
||||
*/
|
||||
bool reached_loiter_target();
|
||||
|
||||
|
||||
/**
|
||||
* Returns true if following a circle (loiter)
|
||||
*/
|
||||
bool circle_mode() {
|
||||
return _circle_mode;
|
||||
}
|
||||
|
||||
|
||||
/**
|
||||
* Get the switch distance
|
||||
*
|
||||
* This is the distance at which the system will
|
||||
* switch to the next waypoint. This depends on the
|
||||
* period and damping
|
||||
*
|
||||
* @param waypoint_switch_radius The switching radius the waypoint has set.
|
||||
*/
|
||||
float switch_distance(float waypoint_switch_radius);
|
||||
|
||||
|
||||
/**
|
||||
* Navigate between two waypoints
|
||||
*
|
||||
* Calling this function with two waypoints results in the
|
||||
* control outputs to fly to the line segment defined by
|
||||
* the points and once captured following the line segment.
|
||||
* This follows the logic in [1].
|
||||
*
|
||||
* @return sets _lateral_accel setpoint
|
||||
*/
|
||||
void navigate_waypoints(const math::Vector<2> &vector_A, const math::Vector<2> &vector_B, const math::Vector<2> &vector_curr_position,
|
||||
const math::Vector<2> &ground_speed);
|
||||
|
||||
|
||||
/**
|
||||
* Navigate on an orbit around a loiter waypoint.
|
||||
*
|
||||
* This allow orbits smaller than the L1 length,
|
||||
* this modification was introduced in [2].
|
||||
*
|
||||
* @return sets _lateral_accel setpoint
|
||||
*/
|
||||
void navigate_loiter(const math::Vector<2> &vector_A, const math::Vector<2> &vector_curr_position, float radius, int8_t loiter_direction,
|
||||
const math::Vector<2> &ground_speed_vector);
|
||||
|
||||
|
||||
/**
|
||||
* Navigate on a fixed bearing.
|
||||
*
|
||||
* This only holds a certain direction and does not perform cross
|
||||
* track correction. Helpful for semi-autonomous modes. Introduced
|
||||
* by [2].
|
||||
*
|
||||
* @return sets _lateral_accel setpoint
|
||||
*/
|
||||
void navigate_heading(float navigation_heading, float current_heading, const math::Vector<2> &ground_speed);
|
||||
|
||||
|
||||
/**
|
||||
* Keep the wings level.
|
||||
*
|
||||
* This is typically needed for maximum-lift-demand situations,
|
||||
* such as takeoff or near stall. Introduced in [2].
|
||||
*/
|
||||
void navigate_level_flight(float current_heading);
|
||||
|
||||
|
||||
/**
|
||||
* Set the L1 period.
|
||||
*/
|
||||
void set_l1_period(float period) {
|
||||
_L1_period = period;
|
||||
/* calculate the ratio introduced in [2] */
|
||||
_L1_ratio = 1.0f / M_PI_F * _L1_damping * _L1_period;
|
||||
/* calculate normalized frequency for heading tracking */
|
||||
_heading_omega = sqrtf(2.0f) * M_PI_F / _L1_period;
|
||||
}
|
||||
|
||||
|
||||
/**
|
||||
* Set the L1 damping factor.
|
||||
*
|
||||
* The original publication recommends a default of sqrt(2) / 2 = 0.707
|
||||
*/
|
||||
void set_l1_damping(float damping) {
|
||||
_L1_damping = damping;
|
||||
/* calculate the ratio introduced in [2] */
|
||||
_L1_ratio = 1.0f / M_PI_F * _L1_damping * _L1_period;
|
||||
/* calculate the L1 gain (following [2]) */
|
||||
_K_L1 = 4.0f * _L1_damping * _L1_damping;
|
||||
}
|
||||
|
||||
|
||||
/**
|
||||
* Set the maximum roll angle output in radians
|
||||
*
|
||||
*/
|
||||
void set_l1_roll_limit(float roll_lim_rad) {
|
||||
_roll_lim_rad = roll_lim_rad;
|
||||
}
|
||||
|
||||
private:
|
||||
|
||||
float _lateral_accel; ///< Lateral acceleration setpoint in m/s^2
|
||||
float _L1_distance; ///< L1 lead distance, defined by period and damping
|
||||
bool _circle_mode; ///< flag for loiter mode
|
||||
float _nav_bearing; ///< bearing to L1 reference point
|
||||
float _bearing_error; ///< bearing error
|
||||
float _crosstrack_error; ///< crosstrack error in meters
|
||||
float _target_bearing; ///< the heading setpoint
|
||||
|
||||
float _L1_period; ///< L1 tracking period in seconds
|
||||
float _L1_damping; ///< L1 damping ratio
|
||||
float _L1_ratio; ///< L1 ratio for navigation
|
||||
float _K_L1; ///< L1 control gain for _L1_damping
|
||||
float _heading_omega; ///< Normalized frequency
|
||||
|
||||
float _roll_lim_rad; ///<maximum roll angle
|
||||
|
||||
/**
|
||||
* Convert a 2D vector from WGS84 to planar coordinates.
|
||||
*
|
||||
* This converts from latitude and longitude to planar
|
||||
* coordinates with (0,0) being at the position of ref and
|
||||
* returns a vector in meters towards wp.
|
||||
*
|
||||
* @param ref The reference position in WGS84 coordinates
|
||||
* @param wp The point to convert to into the local coordinates, in WGS84 coordinates
|
||||
* @return The vector in meters pointing from the reference position to the coordinates
|
||||
*/
|
||||
math::Vector<2> get_local_planar_vector(const math::Vector<2> &origin, const math::Vector<2> &target) const;
|
||||
|
||||
};
|
||||
|
||||
|
||||
#endif /* ECL_L1_POS_CONTROLLER_H */
|
||||
Reference in New Issue
Block a user