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LibrePilot/flight/libraries/paths.c
Richard Flay (Hyper) 87fcf9fa8b Merge branch 'next' into hyper/OP-931_extra_compiler_warnings and update as necessary.
Hopefully properly fixes conflicts:
	flight/modules/Attitude/attitude.c
	flight/modules/ManualControl/manualcontrol.c
	flight/modules/Osd/WavPlayer/wavplayer.c
	flight/modules/Osd/osdgen/osdgen.c
	flight/modules/System/systemmod.c
	ground/uavobjgenerator/generators/flight/uavobjectgeneratorflight.cpp
2013-05-04 11:12:44 +09:30

254 lines
8.9 KiB
C

/**
******************************************************************************
*
* @file paths.c
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2012.
* @brief Library path manipulation
*
* @see The GNU Public License (GPL) Version 3
*
*****************************************************************************/
/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <pios.h>
#include <pios_math.h>
#include "paths.h"
#include "uavobjectmanager.h" // <--.
#include "pathdesired.h" //<-- needed only for correct ENUM macro usage with path modes (PATHDESIRED_MODE_xxx,
// no direct UAVObject usage allowed in this file
// private functions
static void path_endpoint(float * start_point, float * end_point, float * cur_point, struct path_status * status);
static void path_vector(float * start_point, float * end_point, float * cur_point, struct path_status * status);
static void path_circle(float * start_point, float * end_point, float * cur_point, struct path_status * status, bool clockwise);
/**
* @brief Compute progress along path and deviation from it
* @param[in] start_point Starting point
* @param[in] end_point Ending point
* @param[in] cur_point Current location
* @param[in] mode Path following mode
* @param[out] status Structure containing progress along path and deviation
*/
void path_progress(float * start_point, float * end_point, float * cur_point, struct path_status * status, uint8_t mode)
{
switch (mode) {
case PATHDESIRED_MODE_FLYVECTOR:
case PATHDESIRED_MODE_DRIVEVECTOR:
return path_vector(start_point, end_point, cur_point, status);
break;
case PATHDESIRED_MODE_FLYCIRCLERIGHT:
case PATHDESIRED_MODE_DRIVECIRCLERIGHT:
return path_circle(start_point, end_point, cur_point, status, 1);
break;
case PATHDESIRED_MODE_FLYCIRCLELEFT:
case PATHDESIRED_MODE_DRIVECIRCLELEFT:
return path_circle(start_point, end_point, cur_point, status, 0);
break;
case PATHDESIRED_MODE_FLYENDPOINT:
case PATHDESIRED_MODE_DRIVEENDPOINT:
default:
// use the endpoint as default failsafe if called in unknown modes
return path_endpoint(start_point, end_point, cur_point, status);
break;
}
}
/**
* @brief Compute progress towards endpoint. Deviation equals distance
* @param[in] start_point Starting point
* @param[in] end_point Ending point
* @param[in] cur_point Current location
* @param[out] status Structure containing progress along path and deviation
*/
static void path_endpoint(float * start_point, float * end_point, float * cur_point, struct path_status * status)
{
float path_north, path_east, diff_north, diff_east;
float dist_path, dist_diff;
// we do not correct in this mode
status->correction_direction[0] = status->correction_direction[1] = 0;
// Distance to go
path_north = end_point[0] - start_point[0];
path_east = end_point[1] - start_point[1];
// Current progress location relative to end
diff_north = end_point[0] - cur_point[0];
diff_east = end_point[1] - cur_point[1];
dist_diff = sqrtf(diff_north * diff_north + diff_east * diff_east);
dist_path = sqrtf(path_north * path_north + path_east * path_east);
if (dist_diff < 1e-6f ) {
status->fractional_progress = 1;
status->error = 0;
status->path_direction[0] = status->path_direction[1] = 0;
return;
}
status->fractional_progress = 1 - dist_diff / (1 + dist_path);
status->error = dist_diff;
// Compute direction to travel
status->path_direction[0] = diff_north / dist_diff;
status->path_direction[1] = diff_east / dist_diff;
}
/**
* @brief Compute progress along path and deviation from it
* @param[in] start_point Starting point
* @param[in] end_point Ending point
* @param[in] cur_point Current location
* @param[out] status Structure containing progress along path and deviation
*/
static void path_vector(float * start_point, float * end_point, float * cur_point, struct path_status * status)
{
float path_north, path_east, diff_north, diff_east;
float dist_path;
float dot;
float normal[2];
// Distance to go
path_north = end_point[0] - start_point[0];
path_east = end_point[1] - start_point[1];
// Current progress location relative to start
diff_north = cur_point[0] - start_point[0];
diff_east = cur_point[1] - start_point[1];
dot = path_north * diff_north + path_east * diff_east;
dist_path = sqrtf(path_north * path_north + path_east * path_east);
if (dist_path < 1e-6f){
// if the path is too short, we cannot determine vector direction.
// Fly towards the endpoint to prevent flying away,
// but assume progress=1 either way.
path_endpoint(start_point, end_point, cur_point, status);
status->fractional_progress = 1;
return;
}
// Compute the normal to the path
normal[0] = -path_east / dist_path;
normal[1] = path_north / dist_path;
status->fractional_progress = dot / (dist_path * dist_path);
status->error = normal[0] * diff_north + normal[1] * diff_east;
// Compute direction to correct error
status->correction_direction[0] = (status->error > 0) ? -normal[0] : normal[0];
status->correction_direction[1] = (status->error > 0) ? -normal[1] : normal[1];
// Now just want magnitude of error
status->error = fabs(status->error);
// Compute direction to travel
status->path_direction[0] = path_north / dist_path;
status->path_direction[1] = path_east / dist_path;
}
/**
* @brief Compute progress along circular path and deviation from it
* @param[in] start_point Starting point
* @param[in] end_point Center point
* @param[in] cur_point Current location
* @param[out] status Structure containing progress along path and deviation
*/
static void path_circle(float * start_point, float * end_point, float * cur_point, struct path_status * status, bool clockwise)
{
float radius_north, radius_east, diff_north, diff_east;
float radius, cradius;
float normal[2];
float progress;
float a_diff, a_radius;
// Radius
radius_north = end_point[0] - start_point[0];
radius_east = end_point[1] - start_point[1];
// Current location relative to center
diff_north = cur_point[0] - end_point[0];
diff_east = cur_point[1] - end_point[1];
radius = sqrtf(powf(radius_north, 2) + powf(radius_east, 2));
cradius = sqrtf(powf(diff_north, 2) + powf(diff_east, 2));
if (cradius < 1e-6f) {
// cradius is zero, just fly somewhere and make sure correction is still a normal
status->fractional_progress = 1;
status->error = radius;
status->correction_direction[0] = 0;
status->correction_direction[1] = 1;
status->path_direction[0] = 1;
status->path_direction[1] = 0;
return;
}
if (clockwise) {
// Compute the normal to the radius clockwise
normal[0] = -diff_east / cradius;
normal[1] = diff_north / cradius;
} else {
// Compute the normal to the radius counter clockwise
normal[0] = diff_east / cradius;
normal[1] = -diff_north / cradius;
}
// normalize progress to 0..1
a_diff = atan2f(diff_north, diff_east);
a_radius = atan2f(radius_north, radius_east);
if (a_diff < 0) {
a_diff += 2.0f * M_PI_F;
}
if (a_radius < 0) {
a_radius += 2.0f * M_PI_F;
}
progress = (a_diff - a_radius + M_PI_F) / (2.0f * M_PI_F);
if (progress < 0) {
progress += 1.0f;
} else if (progress >= 1.0f) {
progress -= 1.0f;
}
if (clockwise) {
progress = 1 - progress;
}
status->fractional_progress = progress;
// error is current radius minus wanted radius - positive if too close
status->error = radius - cradius;
// Compute direction to correct error
status->correction_direction[0] = (status->error > 0 ? 1 : -1) * diff_north / cradius;
status->correction_direction[1] = (status->error > 0 ? 1 : -1) * diff_east / cradius;
// Compute direction to travel
status->path_direction[0] = normal[0];
status->path_direction[1] = normal[1];
status->error = fabs(status->error);
}