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/****************************************************************************
*
* Copyright (C) 2012 PX4 Development Team. All rights reserved.
* Author: @author Thomas Gubler <thomasgubler@student.ethz.ch>
* @author Doug Weibel <douglas.weibel@colorado.edu>
*
* 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 PX4 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 fixedwing_pos_control.c
* Implementation of a fixed wing attitude controller.
*/
#include <nuttx/config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <math.h>
#include <poll.h>
#include <time.h>
#include <drivers/drv_hrt.h>
#include <arch/board/board.h>
#include <uORB/uORB.h>
#include <uORB/topics/vehicle_global_position.h>
#include <uORB/topics/vehicle_global_position_setpoint.h>
#include <uORB/topics/vehicle_attitude_setpoint.h>
#include <uORB/topics/manual_control_setpoint.h>
#include <uORB/topics/actuator_controls.h>
#include <uORB/topics/vehicle_rates_setpoint.h>
#include <uORB/topics/vehicle_attitude.h>
#include <systemlib/param/param.h>
#include <systemlib/pid/pid.h>
#include <systemlib/geo/geo.h>
#include <systemlib/systemlib.h>
/*
* Controller parameters, accessible via MAVLink
*
*/
PARAM_DEFINE_FLOAT(FW_HEADING_P, 0.1f);
PARAM_DEFINE_FLOAT(FW_XTRACK_P, 0.01745f); // Radians per meter off track
PARAM_DEFINE_FLOAT(FW_ALT_P, 0.1f);
PARAM_DEFINE_FLOAT(FW_ROLL_LIM, 0.7f); // Roll angle limit in radians
PARAM_DEFINE_FLOAT(FW_PITCH_LIM, 0.35f); // Pitch angle limit in radians
struct fw_pos_control_params {
float heading_p;
float headingr_p;
float headingr_i;
float xtrack_p;
float altitude_p;
float roll_lim;
float pitch_lim;
};
struct fw_pos_control_param_handles {
param_t heading_p;
param_t headingr_p;
param_t headingr_i;
param_t xtrack_p;
param_t altitude_p;
param_t roll_lim;
param_t pitch_lim;
};
struct planned_path_segments_s {
bool segment_type;
double start_lat; // Start of line or center of arc
double start_lon;
double end_lat;
double end_lon;
float radius; // Radius of arc
float arc_start_bearing; // Bearing from center to start of arc
float arc_sweep; // Angle (radians) swept out by arc around center.
// Positive for clockwise, negative for counter-clockwise
};
/* Prototypes */
/* Internal Prototypes */
static int parameters_init(struct fw_pos_control_param_handles *h);
static int parameters_update(const struct fw_pos_control_param_handles *h, struct fw_pos_control_params *p);
/**
* Deamon management function.
*/
__EXPORT int fixedwing_pos_control_main(int argc, char *argv[]);
/**
* Mainloop of deamon.
*/
int fixedwing_pos_control_thread_main(int argc, char *argv[]);
/**
* Print the correct usage.
*/
static void usage(const char *reason);
/* Variables */
static bool thread_should_exit = false; /**< Deamon exit flag */
static bool thread_running = false; /**< Deamon status flag */
static int deamon_task; /**< Handle of deamon task / thread */
/**
* Parameter management
*/
static int parameters_init(struct fw_pos_control_param_handles *h)
{
/* PID parameters */
h->heading_p = param_find("FW_HEADING_P");
h->headingr_p = param_find("FW_HEADINGR_P");
h->headingr_i = param_find("FW_HEADINGR_I");
h->xtrack_p = param_find("FW_XTRACK_P");
h->altitude_p = param_find("FW_ALT_P");
h->roll_lim = param_find("FW_ROLL_LIM");
h->pitch_lim = param_find("FW_PITCH_LIM");
return OK;
}
static int parameters_update(const struct fw_pos_control_param_handles *h, struct fw_pos_control_params *p)
{
param_get(h->heading_p, &(p->heading_p));
param_get(h->headingr_p, &(p->headingr_p));
param_get(h->headingr_i, &(p->headingr_i));
param_get(h->xtrack_p, &(p->xtrack_p));
param_get(h->altitude_p, &(p->altitude_p));
param_get(h->roll_lim, &(p->roll_lim));
param_get(h->pitch_lim, &(p->pitch_lim));
return OK;
}
/* Main Thread */
int fixedwing_pos_control_thread_main(int argc, char *argv[])
{
/* read arguments */
bool verbose = false;
for (int i = 1; i < argc; i++) {
if (strcmp(argv[i], "-v") == 0 || strcmp(argv[i], "--verbose") == 0) {
verbose = true;
}
}
/* welcome user */
printf("[fixedwing att_control] started\n");
/* declare and safely initialize all structs */
struct vehicle_global_position_s global_pos;
memset(&global_pos, 0, sizeof(global_pos));
struct vehicle_global_position_s start_pos; // Temporary variable, replace with
memset(&start_pos, 0, sizeof(start_pos)); // previous waypoint when available
struct vehicle_global_position_setpoint_s global_setpoint;
memset(&global_setpoint, 0, sizeof(global_setpoint));
struct vehicle_attitude_s att;
memset(&att, 0, sizeof(att));
struct crosstrack_error_s xtrack_err;
memset(&xtrack_err, 0, sizeof(xtrack_err));
/* output structs */
struct vehicle_attitude_setpoint_s attitude_setpoint;
memset(&attitude_setpoint, 0, sizeof(attitude_setpoint));
/* publish attitude setpoint */
attitude_setpoint.roll_body = 0.0f;
attitude_setpoint.pitch_body = 0.0f;
attitude_setpoint.yaw_body = 0.0f;
orb_advert_t attitude_setpoint_pub = orb_advertise(ORB_ID(vehicle_attitude_setpoint), &attitude_setpoint);
/* subscribe */
int global_pos_sub = orb_subscribe(ORB_ID(vehicle_global_position));
int global_setpoint_sub = orb_subscribe(ORB_ID(vehicle_global_position_setpoint));
int att_sub = orb_subscribe(ORB_ID(vehicle_attitude));
/* Setup of loop */
struct pollfd fds = { .fd = att_sub, .events = POLLIN };
bool global_sp_updated_set_once = false;
float psi_track = 0.0f;
while(!thread_should_exit)
{
/* wait for a sensor update, check for exit condition every 500 ms */
poll(&fds, 1, 500);
static int counter = 0;
static bool initialized = false;
static struct fw_pos_control_params p;
static struct fw_pos_control_param_handles h;
PID_t heading_controller;
PID_t heading_rate_controller;
PID_t offtrack_controller;
PID_t altitude_controller;
static uint64_t last_run = 0;
const float deltaT = (hrt_absolute_time() - last_run) / 1000000.0f;
last_run = hrt_absolute_time();
if(!initialized)
{
parameters_init(&h);
parameters_update(&h, &p);
pid_init(&heading_controller, p.heading_p, 0.0f, 0.0f, 0.0f, 10000.0f, PID_MODE_DERIVATIV_NONE); //arbitrary high limit
pid_init(&heading_rate_controller, p.headingr_p, p.headingr_i, 0.0f, 0.0f, p.roll_lim, PID_MODE_DERIVATIV_NONE);
pid_init(&altitude_controller, p.altitude_p, 0.0f, 0.0f, 0.0f, p.pitch_lim, PID_MODE_DERIVATIV_NONE);
pid_init(&offtrack_controller, p.xtrack_p, 0.0f, 0.0f, 0.0f , 60.0f*M_DEG_TO_RAD, PID_MODE_DERIVATIV_NONE); //TODO: remove hardcoded value
initialized = true;
}
/* load new parameters with lower rate */
if (counter % 100 == 0) {
/* update parameters from storage */
parameters_update(&h, &p);
pid_set_parameters(&heading_controller, p.heading_p, 0, 0, 0, 10000.0f); //arbitrary high limit
pid_set_parameters(&heading_rate_controller, p.headingr_p, p.headingr_i, 0, 0, p.roll_lim);
pid_set_parameters(&altitude_controller, p.altitude_p, 0, 0, 0, p.pitch_lim);
pid_set_parameters(&offtrack_controller, p.xtrack_p, 0, 0, 0, 60.0f*M_DEG_TO_RAD); //TODO: remove hardcoded value
}
/* Check if there is a new position or setpoint */
bool pos_updated;
orb_check(global_pos_sub, &pos_updated);
bool global_sp_updated;
orb_check(global_setpoint_sub, &global_sp_updated);
/* Load local copies */
orb_copy(ORB_ID(vehicle_attitude), att_sub, &att);
if(pos_updated)
orb_copy(ORB_ID(vehicle_global_position), global_pos_sub, &global_pos);
if (global_sp_updated)
orb_copy(ORB_ID(vehicle_global_position_setpoint), global_setpoint_sub, &global_setpoint);
if(global_sp_updated) {
start_pos = global_pos; //for now using the current position as the startpoint (= approx. last waypoint because the setpoint switch occurs at the waypoint)
global_sp_updated_set_once = true;
psi_track = get_bearing_to_next_waypoint((double)global_pos.lat / (double)1e7d, (double)global_pos.lon / (double)1e7d,
(double)global_setpoint.lat / (double)1e7d, (double)global_setpoint.lon / (double)1e7d);
printf("psi_track: %0.4f\n", (double)psi_track);
}
/* Control */
/* Simple Horizontal Control */
if(global_sp_updated_set_once)
{
// if (counter % 100 == 0)
// printf("lat_sp %d, ln_sp %d, lat: %d, lon: %d\n", global_setpoint.lat, global_setpoint.lon, global_pos.lat, global_pos.lon);
/* calculate crosstrack error */
// Only the case of a straight line track following handled so far
int distance_res = get_distance_to_line(&xtrack_err, (double)global_pos.lat / (double)1e7d, (double)global_pos.lon / (double)1e7d,
(double)start_pos.lat / (double)1e7d, (double)start_pos.lon / (double)1e7d,
(double)global_setpoint.lat / (double)1e7d, (double)global_setpoint.lon / (double)1e7d);
if(!(distance_res != OK || xtrack_err.past_end)) {
float delta_psi_c = -pid_calculate(&offtrack_controller, 0, xtrack_err.distance, 0.0f, 0.0f); //p.xtrack_p * xtrack_err.distance; //(-) because z axis points downwards
float psi_c = psi_track + delta_psi_c;
float psi_e = psi_c - att.yaw;
/* shift error to prevent wrapping issues */
psi_e = _wrap_pi(psi_e);
/* calculate roll setpoint, do this artificially around zero */
//TODO: psi rate loop incomplete
float delta_psi_rate_c = pid_calculate(&heading_controller, psi_e, 0.0f, 0.0f, 0.0f);
float psi_rate_track = 0; //=V_gr/r_track , this will be needed for implementation of arc following
float psi_rate_c = delta_psi_rate_c + psi_rate_track;
//TODO limit turn rate
float psi_rate_e = psi_rate_c - att.yawspeed;
float psi_rate_e_scaled = psi_rate_e * sqrtf(pow(global_pos.vx,2) + pow(global_pos.vy,2)) / 9.81f; //* V_gr / g
attitude_setpoint.roll_body = pid_calculate(&heading_rate_controller, psi_rate_e_scaled, 0.0f, 0.0f, deltaT);
// if (counter % 100 == 0)
// printf("xtrack_err.distance: %0.4f, delta_psi_c: %0.4f\n",xtrack_err.distance, delta_psi_c);
}
else {
if (counter % 100 == 0)
printf("distance_res: %d, past_end %d\n", distance_res, xtrack_err.past_end);
}
}
/* Very simple Altitude Control */
if(global_sp_updated_set_once && pos_updated)
{
//TODO: take care of relative vs. ab. altitude
attitude_setpoint.pitch_body = pid_calculate(&altitude_controller, global_setpoint.altitude, global_pos.alt, 0.0f, 0.0f);
}
/*Publish the attitude setpoint */
orb_publish(ORB_ID(vehicle_attitude_setpoint), attitude_setpoint_pub, &attitude_setpoint);
counter++;
}
printf("[fixedwing_pos_control] exiting.\n");
thread_running = false;
close(attitude_setpoint_pub);
fflush(stdout);
exit(0);
return 0;
}
/* Startup Functions */
static void
usage(const char *reason)
{
if (reason)
fprintf(stderr, "%s\n", reason);
fprintf(stderr, "usage: fixedwing_pos_control {start|stop|status}\n\n");
exit(1);
}
/**
* The deamon app only briefly exists to start
* the background job. The stack size assigned in the
* Makefile does only apply to this management task.
*
* The actual stack size should be set in the call
* to task_create().
*/
int fixedwing_pos_control_main(int argc, char *argv[])
{
if (argc < 1)
usage("missing command");
if (!strcmp(argv[1], "start")) {
if (thread_running) {
printf("fixedwing_pos_control already running\n");
/* this is not an error */
exit(0);
}
thread_should_exit = false;
deamon_task = task_spawn("fixedwing_pos_control",
SCHED_DEFAULT,
SCHED_PRIORITY_MAX - 20,
4096,
fixedwing_pos_control_thread_main,
(argv) ? (const char **)&argv[2] : (const char **)NULL);
thread_running = true;
exit(0);
}
if (!strcmp(argv[1], "stop")) {
thread_should_exit = true;
exit(0);
}
if (!strcmp(argv[1], "status")) {
if (thread_running) {
printf("\tfixedwing_pos_control is running\n");
} else {
printf("\tfixedwing_pos_control not started\n");
}
exit(0);
}
usage("unrecognized command");
exit(1);
}
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