/****************************************************************************
*
* Copyright (c) 2013, 2014 PX4 Development Team. All rights reserved.
* Author: @author Tobias Naegeli <naegelit@student.ethz.ch>
* @author Lorenz Meier <lm@inf.ethz.ch>
* @author Anton Babushkin <anton.babushkin@me.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 mc_att_control_main.c
* Multicopter attitude controller.
*
* The controller has two loops: P loop for angular error and PD loop for angular rate error.
* Desired rotation calculated keeping in mind that yaw response is normally slower than roll/pitch.
* For small deviations controller rotates copter to have shortest path of thrust vector and independently rotates around yaw,
* so actual rotation axis is not constant. For large deviations controller rotates copter around fixed axis.
* These two approaches fused seamlessly with weight depending on angular error.
* When thrust vector directed near-horizontally (e.g. roll ~= PI/2) yaw setpoint ignored because of singularity.
* Controller doesn't use Euler angles for work, they generated only for more human-friendly control and logging.
* If rotation matrix setpoint is invalid it will be generated from Euler angles for compatibility with old position controllers.
*/
#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_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 <uORB/topics/vehicle_control_mode.h>
#include <uORB/topics/actuator_armed.h>
#include <uORB/topics/parameter_update.h>
#include <systemlib/param/param.h>
#include <systemlib/err.h>
#include <systemlib/pid/pid.h>
#include <systemlib/perf_counter.h>
#include <systemlib/systemlib.h>
#include <mathlib/mathlib.h>
#include <lib/geo/geo.h>
/**
* Multicopter attitude control app start / stop handling function
*
* @ingroup apps
*/
extern "C" __EXPORT int mc_att_control_main(int argc, char *argv[]);
#define MIN_TAKEOFF_THROTTLE 0.3f
#define YAW_DEADZONE 0.01f
#define RATES_I_LIMIT 0.5f
class MulticopterAttitudeControl
{
public:
/**
* Constructor
*/
MulticopterAttitudeControl();
/**
* Destructor, also kills the sensors task.
*/
~MulticopterAttitudeControl();
/**
* Start the sensors task.
*
* @return OK on success.
*/
int start();
private:
bool _task_should_exit; /**< if true, sensor task should exit */
int _control_task; /**< task handle for sensor task */
int _att_sub; /**< vehicle attitude subscription */
int _att_sp_sub; /**< vehicle attitude setpoint */
int _control_mode_sub; /**< vehicle control mode subscription */
int _params_sub; /**< notification of parameter updates */
int _manual_sub; /**< notification of manual control updates */
int _arming_sub; /**< arming status of outputs */
orb_advert_t _att_sp_pub; /**< attitude setpoint publication */
orb_advert_t _rates_sp_pub; /**< rate setpoint publication */
orb_advert_t _actuators_0_pub; /**< actuator control group 0 setpoint */
struct vehicle_attitude_s _att; /**< vehicle attitude */
struct vehicle_attitude_setpoint_s _att_sp; /**< vehicle attitude setpoint */
struct manual_control_setpoint_s _manual; /**< r/c channel data */
struct vehicle_control_mode_s _control_mode; /**< vehicle control mode */
struct actuator_controls_s _actuators; /**< actuator control inputs */
struct actuator_armed_s _arming; /**< actuator arming status */
struct vehicle_rates_setpoint_s _rates_sp; /**< vehicle rates setpoint */
perf_counter_t _loop_perf; /**< loop performance counter */
math::Vector<3> _K_p; /**< P gain for position error */
math::Vector<3> _K_rate_p; /**< P gain for angular rate error */
math::Vector<3> _K_rate_i; /**< I gain for angular rate error */
math::Vector<3> _K_rate_d; /**< D gain for angular rate error */
math::Vector<3> _rates_prev; /**< angular rates on previous step */
struct {
param_t att_p;
param_t yaw_p;
param_t att_rate_p;
param_t att_rate_i;
param_t att_rate_d;
param_t yaw_rate_p;
param_t yaw_rate_i;
param_t yaw_rate_d;
} _parameter_handles; /**< handles for interesting parameters */
/**
* Update our local parameter cache.
*/
int parameters_update();
/**
* Update control outputs
*/
void control_update();
/**
* Check for changes in vehicle control mode.
*/
void vehicle_control_mode_poll();
/**
* Check for changes in manual inputs.
*/
void vehicle_manual_poll();
/**
* Check for set triplet updates.
*/
void vehicle_setpoint_poll();
/**
* Check for arming status updates.
*/
void arming_status_poll();
/**
* Shim for calling task_main from task_create.
*/
static void task_main_trampoline(int argc, char *argv[]);
/**
* Main sensor collection task.
*/
void task_main() __attribute__((noreturn));
};
namespace att_control
{
/* oddly, ERROR is not defined for c++ */
#ifdef ERROR
# undef ERROR
#endif
static const int ERROR = -1;
MulticopterAttitudeControl *g_control;
}
MulticopterAttitudeControl::MulticopterAttitudeControl() :
_task_should_exit(false),
_control_task(-1),
/* subscriptions */
_att_sub(-1),
_att_sp_sub(-1),
_control_mode_sub(-1),
_params_sub(-1),
_manual_sub(-1),
_arming_sub(-1),
/* publications */
_att_sp_pub(-1),
_rates_sp_pub(-1),
_actuators_0_pub(-1),
/* performance counters */
_loop_perf(perf_alloc(PC_ELAPSED, "fw att control"))
{
memset(&_att, 0, sizeof(_att));
memset(&_att_sp, 0, sizeof(_att_sp));
memset(&_manual, 0, sizeof(_manual));
memset(&_control_mode, 0, sizeof(_control_mode));
memset(&_arming, 0, sizeof(_arming));
_K_p.zero();
_K_rate_p.zero();
_K_rate_d.zero();
_rates_prev.zero();
_parameter_handles.att_p = param_find("MC_ATT_P");
_parameter_handles.yaw_p = param_find("MC_YAW_P");
_parameter_handles.att_rate_p = param_find("MC_ATTRATE_P");
_parameter_handles.att_rate_i = param_find("MC_ATTRATE_I");
_parameter_handles.att_rate_d = param_find("MC_ATTRATE_D");
_parameter_handles.yaw_rate_p = param_find("MC_YAWRATE_P");
_parameter_handles.yaw_rate_i = param_find("MC_YAWRATE_I");
_parameter_handles.yaw_rate_d = param_find("MC_YAWRATE_D");
/* fetch initial parameter values */
parameters_update();
}
MulticopterAttitudeControl::~MulticopterAttitudeControl()
{
if (_control_task != -1) {
/* task wakes up every 100ms or so at the longest */
_task_should_exit = true;
/* wait for a second for the task to quit at our request */
unsigned i = 0;
do {
/* wait 20ms */
usleep(20000);
/* if we have given up, kill it */
if (++i > 50) {
task_delete(_control_task);
break;
}
} while (_control_task != -1);
}
att_control::g_control = nullptr;
}
int
MulticopterAttitudeControl::parameters_update()
{
float v;
param_get(_parameter_handles.att_p, &v);
_K_p(0) = v;
_K_p(1) = v;
param_get(_parameter_handles.yaw_p, &v);
_K_p(2) = v;
param_get(_parameter_handles.att_rate_p, &v);
_K_rate_p(0) = v;
_K_rate_p(1) = v;
param_get(_parameter_handles.yaw_rate_p, &v);
_K_rate_p(2) = v;
param_get(_parameter_handles.att_rate_i, &v);
_K_rate_i(0) = v;
_K_rate_i(1) = v;
param_get(_parameter_handles.yaw_rate_i, &v);
_K_rate_i(2) = v;
param_get(_parameter_handles.att_rate_d, &v);
_K_rate_d(0) = v;
_K_rate_d(1) = v;
param_get(_parameter_handles.yaw_rate_d, &v);
_K_rate_d(2) = v;
return OK;
}
void
MulticopterAttitudeControl::vehicle_control_mode_poll()
{
bool control_mode_updated;
/* Check HIL state if vehicle status has changed */
orb_check(_control_mode_sub, &control_mode_updated);
if (control_mode_updated) {
orb_copy(ORB_ID(vehicle_control_mode), _control_mode_sub, &_control_mode);
}
}
void
MulticopterAttitudeControl::vehicle_manual_poll()
{
bool manual_updated;
/* get pilots inputs */
orb_check(_manual_sub, &manual_updated);
if (manual_updated) {
orb_copy(ORB_ID(manual_control_setpoint), _manual_sub, &_manual);
}
}
void
MulticopterAttitudeControl::vehicle_setpoint_poll()
{
/* check if there is a new setpoint */
bool att_sp_updated;
orb_check(_att_sp_sub, &att_sp_updated);
if (att_sp_updated) {
orb_copy(ORB_ID(vehicle_attitude_setpoint), _att_sp_sub, &_att_sp);
}
}
void
MulticopterAttitudeControl::arming_status_poll()
{
/* check if there is a new setpoint */
bool arming_updated;
orb_check(_arming_sub, &arming_updated);
if (arming_updated) {
orb_copy(ORB_ID(actuator_armed), _arming_sub, &_arming);
}
}
void
MulticopterAttitudeControl::task_main_trampoline(int argc, char *argv[])
{
att_control::g_control->task_main();
}
void
MulticopterAttitudeControl::task_main()
{
/* inform about start */
warnx("started");
fflush(stdout);
/*
* do subscriptions
*/
_att_sp_sub = orb_subscribe(ORB_ID(vehicle_attitude_setpoint));
_att_sub = orb_subscribe(ORB_ID(vehicle_attitude));
_control_mode_sub = orb_subscribe(ORB_ID(vehicle_control_mode));
_params_sub = orb_subscribe(ORB_ID(parameter_update));
_manual_sub = orb_subscribe(ORB_ID(manual_control_setpoint));
_arming_sub = orb_subscribe(ORB_ID(actuator_armed));
/* rate limit attitude updates to 100Hz */
orb_set_interval(_att_sub, 10);
parameters_update();
/* initialize values of critical structs until first regular update */
_arming.armed = false;
/* get an initial update for all sensor and status data */
vehicle_setpoint_poll();
vehicle_control_mode_poll();
vehicle_manual_poll();
arming_status_poll();
/* setpoint rotation matrix */
math::Matrix<3, 3> R_sp;
R_sp.identity();
/* rotation matrix for current state */
math::Matrix<3, 3> R;
R.identity();
/* current angular rates */
math::Vector<3> rates;
rates.zero();
/* angular rates integral error */
math::Vector<3> rates_int;
rates_int.zero();
/* identity matrix */
math::Matrix<3, 3> I;
I.identity();
math::Quaternion q;
bool reset_yaw_sp = true;
/* wakeup source(s) */
struct pollfd fds[2];
/* Setup of loop */
fds[0].fd = _params_sub;
fds[0].events = POLLIN;
fds[1].fd = _att_sub;
fds[1].events = POLLIN;
while (!_task_should_exit) {
/* wait for up to 500ms for data */
int pret = poll(&fds[0], (sizeof(fds) / sizeof(fds[0])), 100);
/* timed out - periodic check for _task_should_exit, etc. */
if (pret == 0)
continue;
/* this is undesirable but not much we can do - might want to flag unhappy status */
if (pret < 0) {
warn("poll error %d, %d", pret, errno);
continue;
}
perf_begin(_loop_perf);
/* only update parameters if they changed */
if (fds[0].revents & POLLIN) {
/* copy the topic to clear updated flag */
struct parameter_update_s update;
orb_copy(ORB_ID(parameter_update), _params_sub, &update);
parameters_update();
}
/* only run controller if attitude changed */
if (fds[1].revents & POLLIN) {
static uint64_t last_run = 0;
float dt = (hrt_absolute_time() - last_run) / 1000000.0f;
last_run = hrt_absolute_time();
/* guard against too large dt's */
if (dt > 0.02f)
dt = 0.02f;
/* copy attitude topic */
orb_copy(ORB_ID(vehicle_attitude), _att_sub, &_att);
vehicle_setpoint_poll();
vehicle_control_mode_poll();
arming_status_poll();
vehicle_manual_poll();
float yaw_sp_move_rate = 0.0f;
bool publish_att_sp = false;
/* define which input is the dominating control input */
if (_control_mode.flag_control_manual_enabled) {
/* manual input */
if (!_control_mode.flag_control_climb_rate_enabled) {
/* pass throttle directly if not in altitude control mode */
_att_sp.thrust = _manual.throttle;
}
if (!_arming.armed) {
/* reset yaw setpoint when disarmed */
reset_yaw_sp = true;
}
if (_control_mode.flag_control_attitude_enabled) {
/* control attitude, update attitude setpoint depending on mode */
if (_att_sp.thrust < 0.1f) {
// TODO
//if (_status.condition_landed) {
/* reset yaw setpoint if on ground */
// reset_yaw_sp = true;
//}
} else {
if (_manual.yaw < -YAW_DEADZONE || YAW_DEADZONE < _manual.yaw) {
/* move yaw setpoint */
yaw_sp_move_rate = _manual.yaw;
_att_sp.yaw_body = _wrap_pi(_att_sp.yaw_body + yaw_sp_move_rate * dt);
_att_sp.R_valid = false;
publish_att_sp = true;
}
}
/* reset yaw setpint to current position if needed */
if (reset_yaw_sp) {
reset_yaw_sp = false;
_att_sp.yaw_body = _att.yaw;
_att_sp.R_valid = false;
publish_att_sp = true;
}
if (!_control_mode.flag_control_velocity_enabled) {
/* update attitude setpoint if not in position control mode */
_att_sp.roll_body = _manual.roll;
_att_sp.pitch_body = _manual.pitch;
_att_sp.R_valid = false;
publish_att_sp = true;
}
} else {
/* manual rate inputs (ACRO) */
// TODO
/* reset yaw setpoint after ACRO */
reset_yaw_sp = true;
}
} else {
/* reset yaw setpoint after non-manual control */
reset_yaw_sp = true;
}
if (_att_sp.R_valid) {
/* rotation matrix in _att_sp is valid, use it */
R_sp.set(&_att_sp.R_body[0][0]);
} else {
/* rotation matrix in _att_sp is not valid, use euler angles instead */
R_sp.from_euler(_att_sp.roll_body, _att_sp.pitch_body, _att_sp.yaw_body);
/* copy rotation matrix back to setpoint struct */
memcpy(&_att_sp.R_body[0][0], &R_sp.data[0][0], sizeof(_att_sp.R_body));
_att_sp.R_valid = true;
}
if (publish_att_sp) {
/* publish the attitude setpoint */
_att_sp.timestamp = hrt_absolute_time();
if (_att_sp_pub > 0) {
orb_publish(ORB_ID(vehicle_attitude_setpoint), _att_sp_pub, &_att_sp);
} else {
_att_sp_pub = orb_advertise(ORB_ID(vehicle_attitude_setpoint), &_att_sp);
}
}
/* rotation matrix for current state */
R.set(_att.R);
/* current body angular rates */
rates(0) = _att.rollspeed;
rates(1) = _att.pitchspeed;
rates(2) = _att.yawspeed;
/* try to move thrust vector shortest way, because yaw response is slower than roll/pitch */
math::Vector<3> R_z(R(0, 2), R(1, 2), R(2, 2));
math::Vector<3> R_sp_z(R_sp(0, 2), R_sp(1, 2), R_sp(2, 2));
/* axis and sin(angle) of desired rotation */
math::Vector<3> e_R = R.transposed() * (R_z % R_sp_z);
/* calculate angle error */
float e_R_z_sin = e_R.length();
float e_R_z_cos = R_z * R_sp_z;
/* calculate weight for yaw control */
float yaw_w = R_sp(2, 2) * R_sp(2, 2);
/* calculate rotation matrix after roll/pitch only rotation */
math::Matrix<3, 3> R_rp;
if (e_R_z_sin > 0.0f) {
/* get axis-angle representation */
float e_R_z_angle = atan2f(e_R_z_sin, e_R_z_cos);
math::Vector<3> e_R_z_axis = e_R / e_R_z_sin;
e_R = e_R_z_axis * e_R_z_angle;
/* cross product matrix for e_R_axis */
math::Matrix<3, 3> e_R_cp;
e_R_cp.zero();
e_R_cp(0, 1) = -e_R_z_axis(2);
e_R_cp(0, 2) = e_R_z_axis(1);
e_R_cp(1, 0) = e_R_z_axis(2);
e_R_cp(1, 2) = -e_R_z_axis(0);
e_R_cp(2, 0) = -e_R_z_axis(1);
e_R_cp(2, 1) = e_R_z_axis(0);
/* rotation matrix for roll/pitch only rotation */
R_rp = R * (I + e_R_cp * e_R_z_sin + e_R_cp * e_R_cp * (1.0f - e_R_z_cos));
} else {
/* zero roll/pitch rotation */
R_rp = R;
}
/* R_rp and R_sp has the same Z axis, calculate yaw error */
math::Vector<3> R_sp_x(R_sp(0, 0), R_sp(1, 0), R_sp(2, 0));
math::Vector<3> R_rp_x(R_rp(0, 0), R_rp(1, 0), R_rp(2, 0));
e_R(2) = atan2f((R_rp_x % R_sp_x) * R_sp_z, R_rp_x * R_sp_x) * yaw_w;
if (e_R_z_cos < 0.0f) {
/* for large thrust vector rotations use another rotation method:
* calculate angle and axis for R -> R_sp rotation directly */
q.from_dcm(R.transposed() * R_sp);
math::Vector<3> e_R_d = q.imag();
e_R_d.normalize();
e_R_d *= 2.0f * atan2f(e_R_d.length(), q(0));
/* use fusion of Z axis based rotation and direct rotation */
float direct_w = e_R_z_cos * e_R_z_cos * yaw_w;
e_R = e_R * (1.0f - direct_w) + e_R_d * direct_w;
}
/* angular rates setpoint*/
math::Vector<3> rates_sp = _K_p.emult(e_R);
/* feed forward yaw setpoint rate */
rates_sp(2) += yaw_sp_move_rate * yaw_w;
math::Vector<3> rates_err = rates_sp - rates;
math::Vector<3> control = _K_rate_p.emult(rates_err) + _K_rate_d.emult(_rates_prev - rates) / fmaxf(dt, 0.003f) + rates_int;
_rates_prev = rates;
/* update integral */
for (int i = 0; i < 3; i++) {
float rate_i = rates_int(i) + _K_rate_i(i) * rates_err(i) * dt;
if (isfinite(rate_i)) {
if (rate_i > -RATES_I_LIMIT && rate_i < RATES_I_LIMIT && control(i) > -RATES_I_LIMIT && control(i) < RATES_I_LIMIT) {
rates_int(i) = rate_i;
}
}
}
/* publish the attitude rates setpoint */
_rates_sp.roll = rates_sp(0);
_rates_sp.pitch = rates_sp(1);
_rates_sp.yaw = rates_sp(2);
_rates_sp.thrust = _att_sp.thrust;
_rates_sp.timestamp = hrt_absolute_time();
if (_rates_sp_pub > 0) {
orb_publish(ORB_ID(vehicle_rates_setpoint), _rates_sp_pub, &_rates_sp);
} else {
_rates_sp_pub = orb_advertise(ORB_ID(vehicle_rates_setpoint), &_rates_sp);
}
/* publish the attitude controls */
if (_control_mode.flag_control_rates_enabled) {
_actuators.control[0] = (isfinite(control(0))) ? control(0) : 0.0f;
_actuators.control[1] = (isfinite(control(1))) ? control(1) : 0.0f;
_actuators.control[2] = (isfinite(control(2))) ? control(2) : 0.0f;
_actuators.control[3] = (isfinite(_rates_sp.thrust)) ? _rates_sp.thrust : 0.0f;
_actuators.timestamp = hrt_absolute_time();
} else {
/* controller disabled, publish zero attitude controls */
_actuators.control[0] = 0.0f;
_actuators.control[1] = 0.0f;
_actuators.control[2] = 0.0f;
_actuators.control[3] = 0.0f;
_actuators.timestamp = hrt_absolute_time();
}
if (_actuators_0_pub > 0) {
/* publish the attitude setpoint */
orb_publish(ORB_ID(actuator_controls_0), _actuators_0_pub, &_actuators);
} else {
/* advertise and publish */
_actuators_0_pub = orb_advertise(ORB_ID(actuator_controls_0), &_actuators);
}
}
perf_end(_loop_perf);
}
warnx("exit");
_control_task = -1;
_exit(0);
}
int
MulticopterAttitudeControl::start()
{
ASSERT(_control_task == -1);
/* start the task */
_control_task = task_spawn_cmd("mc_att_control",
SCHED_DEFAULT,
SCHED_PRIORITY_MAX - 5,
2048,
(main_t)&MulticopterAttitudeControl::task_main_trampoline,
nullptr);
if (_control_task < 0) {
warn("task start failed");
return -errno;
}
return OK;
}
int mc_att_control_main(int argc, char *argv[])
{
if (argc < 1)
errx(1, "usage: mc_att_control {start|stop|status}");
if (!strcmp(argv[1], "start")) {
if (att_control::g_control != nullptr)
errx(1, "already running");
att_control::g_control = new MulticopterAttitudeControl;
if (att_control::g_control == nullptr)
errx(1, "alloc failed");
if (OK != att_control::g_control->start()) {
delete att_control::g_control;
att_control::g_control = nullptr;
err(1, "start failed");
}
exit(0);
}
if (!strcmp(argv[1], "stop")) {
if (att_control::g_control == nullptr)
errx(1, "not running");
delete att_control::g_control;
att_control::g_control = nullptr;
exit(0);
}
if (!strcmp(argv[1], "status")) {
if (att_control::g_control) {
errx(0, "running");
} else {
errx(1, "not running");
}
}
warnx("unrecognized command");
return 1;
}