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/****************************************************************************
*
* Copyright (C) 2013 Anton Babushkin. All rights reserved.
* Author: Anton Babushkin <rk3dov@gmail.com>
*
* 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 multirotor_pos_control.c
*
* Multirotor position controller
*/
#include <nuttx/config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <stdbool.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <debug.h>
#include <termios.h>
#include <time.h>
#include <sys/prctl.h>
#include <drivers/drv_hrt.h>
#include <uORB/uORB.h>
#include <uORB/topics/parameter_update.h>
#include <uORB/topics/vehicle_status.h>
#include <uORB/topics/vehicle_attitude.h>
#include <uORB/topics/manual_control_setpoint.h>
#include <uORB/topics/vehicle_attitude_setpoint.h>
#include <uORB/topics/vehicle_local_position.h>
#include <uORB/topics/vehicle_local_position_setpoint.h>
#include <systemlib/systemlib.h>
#include <mavlink/mavlink_log.h>
#include "multirotor_pos_control_params.h"
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 */
__EXPORT int multirotor_pos_control_main(int argc, char *argv[]);
/**
* Mainloop of position controller.
*/
static int multirotor_pos_control_thread_main(int argc, char *argv[]);
/**
* Print the correct usage.
*/
static void usage(const char *reason);
static float scale_control(float ctl, float end, float dz);
static float limit_value(float v, float limit);
static float norm(float x, float y);
static void usage(const char *reason) {
if (reason)
fprintf(stderr, "%s\n", reason);
fprintf(stderr, "usage: deamon {start|stop|status} [-p <additional params>]\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_spawn().
*/
int multirotor_pos_control_main(int argc, char *argv[]) {
if (argc < 1)
usage("missing command");
if (!strcmp(argv[1], "start")) {
if (thread_running) {
printf("multirotor_pos_control already running\n");
/* this is not an error */
exit(0);
}
thread_should_exit = false;
deamon_task = task_spawn("multirotor_pos_control",
SCHED_DEFAULT,
SCHED_PRIORITY_MAX - 60,
4096,
multirotor_pos_control_thread_main,
(argv) ? (const char **)&argv[2] : (const char **)NULL);
exit(0);
}
if (!strcmp(argv[1], "stop")) {
thread_should_exit = true;
exit(0);
}
if (!strcmp(argv[1], "status")) {
if (thread_running) {
printf("\tmultirotor_pos_control app is running\n");
} else {
printf("\tmultirotor_pos_control app not started\n");
}
exit(0);
}
usage("unrecognized command");
exit(1);
}
static float scale_control(float ctl, float end, float dz) {
if (ctl > dz) {
return (ctl - dz) / (end - dz);
} else if (ctl < -dz) {
return (ctl + dz) / (end - dz);
} else {
return 0.0f;
}
}
static float limit_value(float v, float limit) {
if (v > limit) {
v = limit;
} else if (v < -limit) {
v = -limit;
}
return v;
}
static float norm(float x, float y) {
return sqrtf(x * x + y * y);
}
static int multirotor_pos_control_thread_main(int argc, char *argv[]) {
/* welcome user */
warnx("started.");
static int mavlink_fd;
mavlink_fd = open(MAVLINK_LOG_DEVICE, 0);
mavlink_log_info(mavlink_fd, "[multirotor_pos_control] started");
/* structures */
struct vehicle_status_s status;
memset(&status, 0, sizeof(status));
struct vehicle_attitude_s att;
memset(&att, 0, sizeof(att));
struct vehicle_attitude_setpoint_s att_sp;
memset(&att_sp, 0, sizeof(att_sp));
struct manual_control_setpoint_s manual;
memset(&manual, 0, sizeof(manual));
struct vehicle_local_position_s local_pos;
memset(&local_pos, 0, sizeof(local_pos));
struct vehicle_local_position_setpoint_s local_pos_sp;
memset(&local_pos_sp, 0, sizeof(local_pos_sp));
/* subscribe to attitude, motor setpoints and system state */
int param_sub = orb_subscribe(ORB_ID(parameter_update));
int state_sub = orb_subscribe(ORB_ID(vehicle_status));
int att_sub = orb_subscribe(ORB_ID(vehicle_attitude));
int att_sp_sub = orb_subscribe(ORB_ID(vehicle_attitude_setpoint));
int manual_sub = orb_subscribe(ORB_ID(manual_control_setpoint));
int local_pos_sp_sub = orb_subscribe(ORB_ID(vehicle_local_position_setpoint));
int local_pos_sub = orb_subscribe(ORB_ID(vehicle_local_position));
/* publish setpoint */
orb_advert_t local_pos_sp_pub = orb_advertise(ORB_ID(vehicle_local_position_setpoint), &local_pos_sp);
orb_advert_t att_sp_pub = orb_advertise(ORB_ID(vehicle_attitude_setpoint), &att_sp);
bool reset_sp_alt = true;
bool reset_sp_pos = true;
hrt_abstime t_prev = 0;
float alt_integral = 0.0f;
/* integrate in NED frame to estimate wind but not attitude offset */
float pos_x_integral = 0.0f;
float pos_y_integral = 0.0f;
const float alt_ctl_dz = 0.2f;
const float pos_ctl_dz = 0.05f;
float home_alt = 0.0f;
hrt_abstime home_alt_t = 0;
thread_running = true;
struct multirotor_position_control_params params;
struct multirotor_position_control_param_handles params_h;
parameters_init(¶ms_h);
parameters_update(¶ms_h, ¶ms);
int paramcheck_counter = 0;
while (!thread_should_exit) {
orb_copy(ORB_ID(vehicle_status), state_sub, &status);
/* check parameters at 1 Hz*/
paramcheck_counter++;
if (paramcheck_counter == 50) {
bool param_updated;
orb_check(param_sub, ¶m_updated);
if (param_updated) {
parameters_update(¶ms_h, ¶ms);
}
paramcheck_counter = 0;
}
/* Check if controller should act */
bool act = status.flag_system_armed && (
/* SAS modes */
(
status.flag_control_manual_enabled &&
status.manual_control_mode == VEHICLE_MANUAL_CONTROL_MODE_SAS && (
status.manual_sas_mode == VEHICLE_MANUAL_SAS_MODE_ALTITUDE ||
status.manual_sas_mode == VEHICLE_MANUAL_SAS_MODE_SIMPLE
)
) ||
/* AUTO mode */
status.state_machine == SYSTEM_STATE_AUTO
);
hrt_abstime t = hrt_absolute_time();
float dt;
if (t_prev != 0) {
dt = (t - t_prev) * 0.000001f;
} else {
dt = 0.0f;
}
t_prev = t;
if (act) {
orb_copy(ORB_ID(manual_control_setpoint), manual_sub, &manual);
orb_copy(ORB_ID(vehicle_attitude), att_sub, &att);
orb_copy(ORB_ID(vehicle_attitude_setpoint), att_sp_sub, &att_sp);
orb_copy(ORB_ID(vehicle_local_position), local_pos_sub, &local_pos);
if (status.state_machine == SYSTEM_STATE_AUTO) {
orb_copy(ORB_ID(vehicle_local_position_setpoint), local_pos_sp_sub, &local_pos_sp);
}
if (reset_sp_alt) {
reset_sp_alt = false;
local_pos_sp.z = local_pos.z;
alt_integral = manual.throttle;
mavlink_log_info(mavlink_fd, "reset alt setpoint: z = %.2f, throttle = %.2f", local_pos_sp.z, manual.throttle);
}
if (status.manual_sas_mode == VEHICLE_MANUAL_SAS_MODE_SIMPLE && reset_sp_pos) {
reset_sp_pos = false;
local_pos_sp.x = local_pos.x;
local_pos_sp.y = local_pos.y;
pos_x_integral = 0.0f;
pos_y_integral = 0.0f;
mavlink_log_info(mavlink_fd, "reset pos setpoint: x = %.2f, y = %.2f", local_pos_sp.x, local_pos_sp.y);
}
float alt_err_linear_limit = params.alt_d / params.alt_p * params.alt_rate_max;
float pos_err_linear_limit = params.pos_d / params.pos_p * params.pos_rate_max;
float pos_sp_speed_x = 0.0f;
float pos_sp_speed_y = 0.0f;
float pos_sp_speed_z = 0.0f;
if (status.flag_control_manual_enabled) {
if (local_pos.home_timestamp != home_alt_t) {
if (home_alt_t != 0) {
/* home alt changed, don't follow large ground level changes in manual flight */
local_pos_sp.z += local_pos.home_alt - home_alt;
}
home_alt_t = local_pos.home_timestamp;
home_alt = local_pos.home_alt;
}
/* move altitude setpoint with manual controls */
float alt_sp_ctl = scale_control(manual.throttle - 0.5f, 0.5f, alt_ctl_dz);
if (alt_sp_ctl != 0.0f) {
pos_sp_speed_z = -alt_sp_ctl * params.alt_rate_max;
local_pos_sp.z += pos_sp_speed_z * dt;
if (local_pos_sp.z > local_pos.z + alt_err_linear_limit) {
local_pos_sp.z = local_pos.z + alt_err_linear_limit;
} else if (local_pos_sp.z < local_pos.z - alt_err_linear_limit) {
local_pos_sp.z = local_pos.z - alt_err_linear_limit;
}
}
if (status.manual_sas_mode == VEHICLE_MANUAL_SAS_MODE_SIMPLE) {
/* move position setpoint with manual controls */
float pos_pitch_sp_ctl = scale_control(-manual.pitch / params.rc_scale_pitch, 1.0f, pos_ctl_dz);
float pos_roll_sp_ctl = scale_control(manual.roll / params.rc_scale_roll, 1.0f, pos_ctl_dz);
if (pos_pitch_sp_ctl != 0.0f || pos_roll_sp_ctl != 0.0f) {
/* calculate direction and increment of control in NED frame */
float pos_sp_ctl_dir = att.yaw + atan2f(pos_roll_sp_ctl, pos_pitch_sp_ctl);
float pos_sp_ctl_speed = norm(pos_pitch_sp_ctl, pos_roll_sp_ctl) * params.pos_rate_max;
pos_sp_speed_x = cosf(pos_sp_ctl_dir) * pos_sp_ctl_speed;
pos_sp_speed_y = sinf(pos_sp_ctl_dir) * pos_sp_ctl_speed;
local_pos_sp.x += pos_sp_speed_x * dt;
local_pos_sp.y += pos_sp_speed_y * dt;
/* limit maximum setpoint from position offset and preserve direction */
float pos_vec_x = local_pos_sp.x - local_pos.x;
float pos_vec_y = local_pos_sp.y - local_pos.y;
float pos_vec_norm = norm(pos_vec_x, pos_vec_y) / pos_err_linear_limit;
if (pos_vec_norm > 1.0f) {
local_pos_sp.x = local_pos.x + pos_vec_x / pos_vec_norm;
local_pos_sp.y = local_pos.y + pos_vec_y / pos_vec_norm;
}
}
}
if (params.hard == 0) {
pos_sp_speed_x = 0.0f;
pos_sp_speed_y = 0.0f;
pos_sp_speed_z = 0.0f;
}
}
/* PID for altitude */
/* don't accelerate more than ALT_RATE_MAX, limit error to corresponding value */
float alt_err = limit_value(local_pos_sp.z - local_pos.z, alt_err_linear_limit);
/* P and D components */
float thrust_ctl_pd = -(alt_err * params.alt_p + (pos_sp_speed_z - local_pos.vz) * params.alt_d); // altitude = -z
/* integrate */
alt_integral += thrust_ctl_pd / params.alt_p * params.alt_i * dt;
if (alt_integral < params.thr_min) {
alt_integral = params.thr_min;
} else if (alt_integral > params.thr_max) {
alt_integral = params.thr_max;
}
/* add I component */
float thrust_ctl = thrust_ctl_pd + alt_integral;
if (thrust_ctl < params.thr_min) {
thrust_ctl = params.thr_min;
} else if (thrust_ctl > params.thr_max) {
thrust_ctl = params.thr_max;
}
if (status.manual_sas_mode == VEHICLE_MANUAL_SAS_MODE_SIMPLE || status.state_machine == SYSTEM_STATE_AUTO) {
/* PID for position */
/* don't accelerate more than POS_RATE_MAX, limit error to corresponding value */
float pos_x_err = limit_value(local_pos.x - local_pos_sp.x, pos_err_linear_limit);
float pos_y_err = limit_value(local_pos.y - local_pos_sp.y, pos_err_linear_limit);
/* P and D components */
float pos_x_ctl_pd = - pos_x_err * params.pos_p + (pos_sp_speed_x - local_pos.vx) * params.pos_d;
float pos_y_ctl_pd = - pos_y_err * params.pos_p + (pos_sp_speed_y - local_pos.vy) * params.pos_d;
/* integrate */
pos_x_integral = limit_value(pos_x_integral + pos_x_ctl_pd / params.pos_p * params.pos_i * dt, params.slope_max);
pos_y_integral = limit_value(pos_y_integral + pos_y_ctl_pd / params.pos_p * params.pos_i * dt, params.slope_max);
/* add I component */
float pos_x_ctl = pos_x_ctl_pd + pos_x_integral;
float pos_y_ctl = pos_y_ctl_pd + pos_y_integral;
/* calculate direction and slope in NED frame */
float dir = atan2f(pos_y_ctl, pos_x_ctl);
/* use approximation: slope ~ sin(slope) = force */
float slope = limit_value(sqrtf(pos_x_ctl * pos_x_ctl + pos_y_ctl * pos_y_ctl), params.slope_max);
/* convert direction to body frame */
dir -= att.yaw;
/* calculate roll and pitch */
att_sp.pitch_body = -cosf(dir) * slope; // reverse pitch
att_sp.roll_body = sinf(dir) * slope;
} else {
reset_sp_pos = true;
}
att_sp.thrust = thrust_ctl;
att_sp.timestamp = hrt_absolute_time();
if (status.flag_control_manual_enabled) {
/* publish local position setpoint in manual mode */
orb_publish(ORB_ID(vehicle_local_position_setpoint), local_pos_sp_pub, &local_pos_sp);
}
/* publish new attitude setpoint */
orb_publish(ORB_ID(vehicle_attitude_setpoint), att_sp_pub, &att_sp);
} else {
reset_sp_alt = true;
reset_sp_pos = true;
}
/* run at approximately 50 Hz */
usleep(20000);
}
printf("[multirotor_pos_control] exiting\n");
mavlink_log_info(mavlink_fd, "[multirotor_pos_control] exiting");
thread_running = false;
fflush(stdout);
return 0;
}
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