/****************************************************************************
*
* Copyright (C) 2012 PX4 Development Team. All rights reserved.
* Author: Tobias Naegeli <naegelit@student.ethz.ch>
* Lorenz Meier <lm@inf.ethz.ch>
*
* 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
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* 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 attitude_estimator_ekf_main.c
*
* Extended Kalman Filter for Attitude Estimation.
*/
#include <nuttx/config.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdbool.h>
#include <poll.h>
#include <fcntl.h>
#include <v1.0/common/mavlink.h>
#include <float.h>
#include <nuttx/sched.h>
#include <sys/prctl.h>
#include <termios.h>
#include <errno.h>
#include <limits.h>
#include <math.h>
#include <uORB/uORB.h>
#include <uORB/topics/debug_key_value.h>
#include <uORB/topics/sensor_combined.h>
#include <uORB/topics/vehicle_attitude.h>
#include <uORB/topics/vehicle_status.h>
#include <uORB/topics/parameter_update.h>
#include <drivers/drv_hrt.h>
#include <systemlib/systemlib.h>
#include <systemlib/perf_counter.h>
#include <systemlib/err.h>
#include "codegen/attitudeKalmanfilter_initialize.h"
#include "codegen/attitudeKalmanfilter.h"
#include "attitude_estimator_ekf_params.h"
__EXPORT int attitude_estimator_ekf_main(int argc, char *argv[]);
static unsigned int loop_interval_alarm = 6500; // loop interval in microseconds
static float dt = 0.005f;
/* state vector x has the following entries [ax,ay,az||mx,my,mz||wox,woy,woz||wx,wy,wz]' */
static float z_k[9] = {0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 9.81f, 0.2f, -0.2f, 0.2f}; /**< Measurement vector */
static float x_aposteriori_k[12]; /**< states */
static float P_aposteriori_k[144] = {100.f, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 100.f, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 100.f, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 100.f, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 100.f, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 100.f, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 100.f, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 100.f, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 100.f, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0.0f, 100.0f, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0.0f, 0, 100.0f, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0.0f, 0, 0, 100.0f,
}; /**< init: diagonal matrix with big values */
static float x_aposteriori[12];
static float P_aposteriori[144];
/* output euler angles */
static float euler[3] = {0.0f, 0.0f, 0.0f};
static float Rot_matrix[9] = {1.f, 0, 0,
0, 1.f, 0,
0, 0, 1.f
}; /**< init: identity matrix */
static bool thread_should_exit = false; /**< Deamon exit flag */
static bool thread_running = false; /**< Deamon status flag */
static int attitude_estimator_ekf_task; /**< Handle of deamon task / thread */
/**
* Mainloop of attitude_estimator_ekf.
*/
int attitude_estimator_ekf_thread_main(int argc, char *argv[]);
/**
* Print the correct usage.
*/
static void usage(const char *reason);
static void
usage(const char *reason)
{
if (reason)
fprintf(stderr, "%s\n", reason);
fprintf(stderr, "usage: attitude_estimator_ekf {start|stop|status} [-p <additional params>]\n\n");
exit(1);
}
/**
* The attitude_estimator_ekf 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 attitude_estimator_ekf_main(int argc, char *argv[])
{
if (argc < 1)
usage("missing command");
if (!strcmp(argv[1], "start")) {
if (thread_running) {
printf("attitude_estimator_ekf already running\n");
/* this is not an error */
exit(0);
}
thread_should_exit = false;
attitude_estimator_ekf_task = task_spawn("attitude_estimator_ekf",
SCHED_DEFAULT,
SCHED_PRIORITY_MAX - 5,
12000,
attitude_estimator_ekf_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("\tattitude_estimator_ekf app is running\n");
} else {
printf("\tattitude_estimator_ekf app not started\n");
}
exit(0);
}
usage("unrecognized command");
exit(1);
}
/*
* [Rot_matrix,x_aposteriori,P_aposteriori] = attitudeKalmanfilter(dt,z_k,x_aposteriori_k,P_aposteriori_k,knownConst)
*/
/*
* EKF Attitude Estimator main function.
*
* Estimates the attitude recursively once started.
*
* @param argc number of commandline arguments (plus command name)
* @param argv strings containing the arguments
*/
int attitude_estimator_ekf_thread_main(int argc, char *argv[])
{
// print text
printf("Extended Kalman Filter Attitude Estimator initialized..\n\n");
fflush(stdout);
int overloadcounter = 19;
/* Initialize filter */
attitudeKalmanfilter_initialize();
/* store start time to guard against too slow update rates */
uint64_t last_run = hrt_absolute_time();
struct sensor_combined_s raw;
memset(&raw, 0, sizeof(raw));
struct vehicle_attitude_s att;
memset(&att, 0, sizeof(att));
struct vehicle_status_s state;
memset(&state, 0, sizeof(state));
uint64_t last_data = 0;
uint64_t last_measurement = 0;
/* subscribe to raw data */
int sub_raw = orb_subscribe(ORB_ID(sensor_combined));
/* rate-limit raw data updates to 200Hz */
orb_set_interval(sub_raw, 4);
/* subscribe to param changes */
int sub_params = orb_subscribe(ORB_ID(parameter_update));
/* subscribe to system state*/
int sub_state = orb_subscribe(ORB_ID(vehicle_status));
/* advertise attitude */
orb_advert_t pub_att = orb_advertise(ORB_ID(vehicle_attitude), &att);
int loopcounter = 0;
int printcounter = 0;
thread_running = true;
/* advertise debug value */
// struct debug_key_value_s dbg = { .key = "", .value = 0.0f };
// orb_advert_t pub_dbg = -1;
float sensor_update_hz[3] = {0.0f, 0.0f, 0.0f};
// XXX write this out to perf regs
/* keep track of sensor updates */
uint32_t sensor_last_count[3] = {0, 0, 0};
uint64_t sensor_last_timestamp[3] = {0, 0, 0};
struct attitude_estimator_ekf_params ekf_params;
struct attitude_estimator_ekf_param_handles ekf_param_handles;
/* initialize parameter handles */
parameters_init(&ekf_param_handles);
uint64_t start_time = hrt_absolute_time();
bool initialized = false;
float gyro_offsets[3] = { 0.0f, 0.0f, 0.0f };
unsigned offset_count = 0;
/* register the perf counter */
perf_counter_t ekf_loop_perf = perf_alloc(PC_ELAPSED, "attitude_estimator_ekf");
/* Main loop*/
while (!thread_should_exit) {
struct pollfd fds[2] = {
{ .fd = sub_raw, .events = POLLIN },
{ .fd = sub_params, .events = POLLIN }
};
int ret = poll(fds, 2, 1000);
if (ret < 0) {
/* XXX this is seriously bad - should be an emergency */
} else if (ret == 0) {
/* check if we're in HIL - not getting sensor data is fine then */
orb_copy(ORB_ID(vehicle_status), sub_state, &state);
if (!state.flag_hil_enabled) {
fprintf(stderr,
"[att ekf] WARNING: Not getting sensors - sensor app running?\n");
}
} else {
/* only update parameters if they changed */
if (fds[1].revents & POLLIN) {
/* read from param to clear updated flag */
struct parameter_update_s update;
orb_copy(ORB_ID(parameter_update), sub_params, &update);
/* update parameters */
parameters_update(&ekf_param_handles, &ekf_params);
}
/* only run filter if sensor values changed */
if (fds[0].revents & POLLIN) {
/* get latest measurements */
orb_copy(ORB_ID(sensor_combined), sub_raw, &raw);
if (!initialized) {
gyro_offsets[0] += raw.gyro_rad_s[0];
gyro_offsets[1] += raw.gyro_rad_s[1];
gyro_offsets[2] += raw.gyro_rad_s[2];
offset_count++;
if (hrt_absolute_time() - start_time > 3000000LL) {
initialized = true;
gyro_offsets[0] /= offset_count;
gyro_offsets[1] /= offset_count;
gyro_offsets[2] /= offset_count;
}
} else {
perf_begin(ekf_loop_perf);
/* Calculate data time difference in seconds */
dt = (raw.timestamp - last_measurement) / 1000000.0f;
last_measurement = raw.timestamp;
uint8_t update_vect[3] = {0, 0, 0};
/* Fill in gyro measurements */
if (sensor_last_count[0] != raw.gyro_counter) {
update_vect[0] = 1;
sensor_last_count[0] = raw.gyro_counter;
sensor_update_hz[0] = 1e6f / (raw.timestamp - sensor_last_timestamp[0]);
sensor_last_timestamp[0] = raw.timestamp;
}
z_k[0] = raw.gyro_rad_s[0] - gyro_offsets[0];
z_k[1] = raw.gyro_rad_s[1] - gyro_offsets[1];
z_k[2] = raw.gyro_rad_s[2] - gyro_offsets[2];
/* update accelerometer measurements */
if (sensor_last_count[1] != raw.accelerometer_counter) {
update_vect[1] = 1;
sensor_last_count[1] = raw.accelerometer_counter;
sensor_update_hz[1] = 1e6f / (raw.timestamp - sensor_last_timestamp[1]);
sensor_last_timestamp[1] = raw.timestamp;
}
z_k[3] = raw.accelerometer_m_s2[0];
z_k[4] = raw.accelerometer_m_s2[1];
z_k[5] = raw.accelerometer_m_s2[2];
/* update magnetometer measurements */
if (sensor_last_count[2] != raw.magnetometer_counter) {
update_vect[2] = 1;
sensor_last_count[2] = raw.magnetometer_counter;
sensor_update_hz[2] = 1e6f / (raw.timestamp - sensor_last_timestamp[2]);
sensor_last_timestamp[2] = raw.timestamp;
}
z_k[6] = raw.magnetometer_ga[0];
z_k[7] = raw.magnetometer_ga[1];
z_k[8] = raw.magnetometer_ga[2];
uint64_t now = hrt_absolute_time();
unsigned int time_elapsed = now - last_run;
last_run = now;
if (time_elapsed > loop_interval_alarm) {
//TODO: add warning, cpu overload here
// if (overloadcounter == 20) {
// printf("CPU OVERLOAD DETECTED IN ATTITUDE ESTIMATOR EKF (%lu > %lu)\n", time_elapsed, loop_interval_alarm);
// overloadcounter = 0;
// }
overloadcounter++;
}
static bool const_initialized = false;
/* initialize with good values once we have a reasonable dt estimate */
if (!const_initialized && dt < 0.05f && dt > 0.005f) {
dt = 0.005f;
parameters_update(&ekf_param_handles, &ekf_params);
x_aposteriori_k[0] = z_k[0];
x_aposteriori_k[1] = z_k[1];
x_aposteriori_k[2] = z_k[2];
x_aposteriori_k[3] = 0.0f;
x_aposteriori_k[4] = 0.0f;
x_aposteriori_k[5] = 0.0f;
x_aposteriori_k[6] = z_k[3];
x_aposteriori_k[7] = z_k[4];
x_aposteriori_k[8] = z_k[5];
x_aposteriori_k[9] = z_k[6];
x_aposteriori_k[10] = z_k[7];
x_aposteriori_k[11] = z_k[8];
const_initialized = true;
}
/* do not execute the filter if not initialized */
if (!const_initialized) {
continue;
}
uint64_t timing_start = hrt_absolute_time();
attitudeKalmanfilter(update_vect, dt, z_k, x_aposteriori_k, P_aposteriori_k, ekf_params.q, ekf_params.r,
euler, Rot_matrix, x_aposteriori, P_aposteriori);
/* swap values for next iteration, check for fatal inputs */
if (isfinite(euler[0]) && isfinite(euler[1]) && isfinite(euler[2])) {
memcpy(P_aposteriori_k, P_aposteriori, sizeof(P_aposteriori_k));
memcpy(x_aposteriori_k, x_aposteriori, sizeof(x_aposteriori_k));
} else {
/* due to inputs or numerical failure the output is invalid, skip it */
continue;
}
if (last_data > 0 && raw.timestamp - last_data > 12000) printf("[attitude estimator ekf] sensor data missed! (%llu)\n", raw.timestamp - last_data);
last_data = raw.timestamp;
/* send out */
att.timestamp = raw.timestamp;
// XXX Apply the same transformation to the rotation matrix
att.roll = euler[0] - ekf_params.roll_off;
att.pitch = euler[1] - ekf_params.pitch_off;
att.yaw = euler[2] - ekf_params.yaw_off;
att.rollspeed = x_aposteriori[0];
att.pitchspeed = x_aposteriori[1];
att.yawspeed = x_aposteriori[2];
att.rollacc = x_aposteriori[3];
att.pitchacc = x_aposteriori[4];
att.yawacc = x_aposteriori[5];
//att.yawspeed =z_k[2] ;
/* copy offsets */
memcpy(&att.rate_offsets, &(x_aposteriori[3]), sizeof(att.rate_offsets));
/* copy rotation matrix */
memcpy(&att.R, Rot_matrix, sizeof(Rot_matrix));
att.R_valid = true;
if (isfinite(att.roll) && isfinite(att.pitch) && isfinite(att.yaw)) {
// Broadcast
orb_publish(ORB_ID(vehicle_attitude), pub_att, &att);
} else {
warnx("NaN in roll/pitch/yaw estimate!");
}
perf_end(ekf_loop_perf);
}
}
}
loopcounter++;
}
thread_running = false;
return 0;
}