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author | Lorenz Meier <lm@inf.ethz.ch> | 2013-06-06 04:39:39 -0700 |
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committer | Lorenz Meier <lm@inf.ethz.ch> | 2013-06-06 04:39:39 -0700 |
commit | 106f4910bead02f0e422c9368fe65d5d5a893db4 (patch) | |
tree | d0e88b9c99f61e8e4ed995ef040790e42c7e87d0 /src/modules | |
parent | 39d6dd3dc6812b26b0c2f49b0a2615290ef88ba6 (diff) | |
parent | 6537759dfc58117258610bb64d621da646d7d4ea (diff) | |
download | px4-firmware-106f4910bead02f0e422c9368fe65d5d5a893db4.tar.gz px4-firmware-106f4910bead02f0e422c9368fe65d5d5a893db4.tar.bz2 px4-firmware-106f4910bead02f0e422c9368fe65d5d5a893db4.zip |
Merge pull request #284 from limhyon/master
Nonlinear complementary SO(3) filter has been implemented.
Diffstat (limited to 'src/modules')
5 files changed, 953 insertions, 0 deletions
diff --git a/src/modules/attitude_estimator_so3_comp/README b/src/modules/attitude_estimator_so3_comp/README new file mode 100644 index 000000000..79c50a531 --- /dev/null +++ b/src/modules/attitude_estimator_so3_comp/README @@ -0,0 +1,5 @@ +Synopsis + + nsh> attitude_estimator_so3_comp start -d /dev/ttyS1 -b 115200 + +Option -d is for debugging packet. See code for detailed packet structure. diff --git a/src/modules/attitude_estimator_so3_comp/attitude_estimator_so3_comp_main.cpp b/src/modules/attitude_estimator_so3_comp/attitude_estimator_so3_comp_main.cpp new file mode 100755 index 000000000..3cbc62ea1 --- /dev/null +++ b/src/modules/attitude_estimator_so3_comp/attitude_estimator_so3_comp_main.cpp @@ -0,0 +1,833 @@ +/* + * Author: Hyon Lim <limhyon@gmail.com, hyonlim@snu.ac.kr> + * + * @file attitude_estimator_so3_comp_main.c + * + * Implementation of nonlinear complementary filters on the SO(3). + * This code performs attitude estimation by using accelerometer, gyroscopes and magnetometer. + * Result is provided as quaternion, 1-2-3 Euler angle and rotation matrix. + * + * Theory of nonlinear complementary filters on the SO(3) is based on [1]. + * Quaternion realization of [1] is based on [2]. + * Optmized quaternion update code is based on Sebastian Madgwick's implementation. + * + * References + * [1] Mahony, R.; Hamel, T.; Pflimlin, Jean-Michel, "Nonlinear Complementary Filters on the Special Orthogonal Group," Automatic Control, IEEE Transactions on , vol.53, no.5, pp.1203,1218, June 2008 + * [2] Euston, M.; Coote, P.; Mahony, R.; Jonghyuk Kim; Hamel, T., "A complementary filter for attitude estimation of a fixed-wing UAV," Intelligent Robots and Systems, 2008. IROS 2008. IEEE/RSJ International Conference on , vol., no., pp.340,345, 22-26 Sept. 2008 + */ + +#include <nuttx/config.h> +#include <unistd.h> +#include <stdlib.h> +#include <string.h> +#include <stdio.h> +#include <stdbool.h> +#include <poll.h> +#include <fcntl.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> + +#ifdef __cplusplus +extern "C" { +#endif +#include "attitude_estimator_so3_comp_params.h" +#ifdef __cplusplus +} +#endif + +extern "C" __EXPORT int attitude_estimator_so3_comp_main(int argc, char *argv[]); + +static bool thread_should_exit = false; /**< Deamon exit flag */ +static bool thread_running = false; /**< Deamon status flag */ +static int attitude_estimator_so3_comp_task; /**< Handle of deamon task / thread */ +static float q0 = 1.0f, q1 = 0.0f, q2 = 0.0f, q3 = 0.0f; /** quaternion of sensor frame relative to auxiliary frame */ +static float dq0 = 0.0f, dq1 = 0.0f, dq2 = 0.0f, dq3 = 0.0f; /** quaternion of sensor frame relative to auxiliary frame */ +static float gyro_bias[3] = {0.0f, 0.0f, 0.0f}; /** bias estimation */ +static bool bFilterInit = false; + +//! Auxiliary variables to reduce number of repeated operations +static float q0q0, q0q1, q0q2, q0q3; +static float q1q1, q1q2, q1q3; +static float q2q2, q2q3; +static float q3q3; + +//! Serial packet related +static int uart; +static int baudrate; + +/** + * Mainloop of attitude_estimator_so3_comp. + */ +int attitude_estimator_so3_comp_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_so3_comp {start|stop|status} [-d <devicename>] [-b <baud rate>]\n" + "-d and -b options are for separate visualization with raw data (quaternion packet) transfer\n" + "ex) attitude_estimator_so3_comp start -d /dev/ttyS1 -b 115200\n"); + exit(1); +} + +/** + * The attitude_estimator_so3_comp 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_so3_comp_main(int argc, char *argv[]) +{ + if (argc < 1) + usage("missing command"); + + + + if (!strcmp(argv[1], "start")) { + + if (thread_running) { + printf("attitude_estimator_so3_comp already running\n"); + /* this is not an error */ + exit(0); + } + + thread_should_exit = false; + attitude_estimator_so3_comp_task = task_spawn("attitude_estimator_so3_comp", + SCHED_DEFAULT, + SCHED_PRIORITY_MAX - 5, + 12400, + attitude_estimator_so3_comp_thread_main, + (const char **)argv); + exit(0); + } + + if (!strcmp(argv[1], "stop")) { + thread_should_exit = true; + + while(thread_running){ + usleep(200000); + printf("."); + } + printf("terminated."); + exit(0); + } + + if (!strcmp(argv[1], "status")) { + if (thread_running) { + printf("\tattitude_estimator_so3_comp app is running\n"); + + } else { + printf("\tattitude_estimator_so3_comp app not started\n"); + } + + exit(0); + } + + usage("unrecognized command"); + exit(1); +} + +//--------------------------------------------------------------------------------------------------- +// Fast inverse square-root +// See: http://en.wikipedia.org/wiki/Fast_inverse_square_root +float invSqrt(float number) { + volatile long i; + volatile float x, y; + volatile const float f = 1.5F; + + x = number * 0.5F; + y = number; + i = * (( long * ) &y); + i = 0x5f375a86 - ( i >> 1 ); + y = * (( float * ) &i); + y = y * ( f - ( x * y * y ) ); + return y; +} + +//! Using accelerometer, sense the gravity vector. +//! Using magnetometer, sense yaw. +void NonlinearSO3AHRSinit(float ax, float ay, float az, float mx, float my, float mz) +{ + float initialRoll, initialPitch; + float cosRoll, sinRoll, cosPitch, sinPitch; + float magX, magY; + float initialHdg, cosHeading, sinHeading; + + initialRoll = atan2(-ay, -az); + initialPitch = atan2(ax, -az); + + cosRoll = cosf(initialRoll); + sinRoll = sinf(initialRoll); + cosPitch = cosf(initialPitch); + sinPitch = sinf(initialPitch); + + magX = mx * cosPitch + my * sinRoll * sinPitch + mz * cosRoll * sinPitch; + + magY = my * cosRoll - mz * sinRoll; + + initialHdg = atan2f(-magY, magX); + + cosRoll = cosf(initialRoll * 0.5f); + sinRoll = sinf(initialRoll * 0.5f); + + cosPitch = cosf(initialPitch * 0.5f); + sinPitch = sinf(initialPitch * 0.5f); + + cosHeading = cosf(initialHdg * 0.5f); + sinHeading = sinf(initialHdg * 0.5f); + + q0 = cosRoll * cosPitch * cosHeading + sinRoll * sinPitch * sinHeading; + q1 = sinRoll * cosPitch * cosHeading - cosRoll * sinPitch * sinHeading; + q2 = cosRoll * sinPitch * cosHeading + sinRoll * cosPitch * sinHeading; + q3 = cosRoll * cosPitch * sinHeading - sinRoll * sinPitch * cosHeading; + + // auxillary variables to reduce number of repeated operations, for 1st pass + q0q0 = q0 * q0; + q0q1 = q0 * q1; + q0q2 = q0 * q2; + q0q3 = q0 * q3; + q1q1 = q1 * q1; + q1q2 = q1 * q2; + q1q3 = q1 * q3; + q2q2 = q2 * q2; + q2q3 = q2 * q3; + q3q3 = q3 * q3; +} + +void NonlinearSO3AHRSupdate(float gx, float gy, float gz, float ax, float ay, float az, float mx, float my, float mz, float twoKp, float twoKi, float dt) { + float recipNorm; + float halfex = 0.0f, halfey = 0.0f, halfez = 0.0f; + + //! Make filter converge to initial solution faster + //! This function assumes you are in static position. + //! WARNING : in case air reboot, this can cause problem. But this is very + //! unlikely happen. + if(bFilterInit == false) + { + NonlinearSO3AHRSinit(ax,ay,az,mx,my,mz); + bFilterInit = true; + } + + //! If magnetometer measurement is available, use it. + if((mx == 0.0f) && (my == 0.0f) && (mz == 0.0f)) { + float hx, hy, hz, bx, bz; + float halfwx, halfwy, halfwz; + + // Normalise magnetometer measurement + // Will sqrt work better? PX4 system is powerful enough? + recipNorm = invSqrt(mx * mx + my * my + mz * mz); + mx *= recipNorm; + my *= recipNorm; + mz *= recipNorm; + + // Reference direction of Earth's magnetic field + hx = 2.0f * (mx * (0.5f - q2q2 - q3q3) + my * (q1q2 - q0q3) + mz * (q1q3 + q0q2)); + hy = 2.0f * (mx * (q1q2 + q0q3) + my * (0.5f - q1q1 - q3q3) + mz * (q2q3 - q0q1)); + hz = 2 * mx * (q1q3 - q0q2) + 2 * my * (q2q3 + q0q1) + 2 * mz * (0.5 - q1q1 - q2q2); + bx = sqrt(hx * hx + hy * hy); + bz = hz; + + // Estimated direction of magnetic field + halfwx = bx * (0.5f - q2q2 - q3q3) + bz * (q1q3 - q0q2); + halfwy = bx * (q1q2 - q0q3) + bz * (q0q1 + q2q3); + halfwz = bx * (q0q2 + q1q3) + bz * (0.5f - q1q1 - q2q2); + + // Error is sum of cross product between estimated direction and measured direction of field vectors + halfex += (my * halfwz - mz * halfwy); + halfey += (mz * halfwx - mx * halfwz); + halfez += (mx * halfwy - my * halfwx); + } + + // Compute feedback only if accelerometer measurement valid (avoids NaN in accelerometer normalisation) + if(!((ax == 0.0f) && (ay == 0.0f) && (az == 0.0f))) { + float halfvx, halfvy, halfvz; + + // Normalise accelerometer measurement + recipNorm = invSqrt(ax * ax + ay * ay + az * az); + ax *= recipNorm; + ay *= recipNorm; + az *= recipNorm; + + // Estimated direction of gravity and magnetic field + halfvx = q1q3 - q0q2; + halfvy = q0q1 + q2q3; + halfvz = q0q0 - 0.5f + q3q3; + + // Error is sum of cross product between estimated direction and measured direction of field vectors + halfex += ay * halfvz - az * halfvy; + halfey += az * halfvx - ax * halfvz; + halfez += ax * halfvy - ay * halfvx; + } + + // Apply feedback only when valid data has been gathered from the accelerometer or magnetometer + if(halfex != 0.0f && halfey != 0.0f && halfez != 0.0f) { + // Compute and apply integral feedback if enabled + if(twoKi > 0.0f) { + gyro_bias[0] += twoKi * halfex * dt; // integral error scaled by Ki + gyro_bias[1] += twoKi * halfey * dt; + gyro_bias[2] += twoKi * halfez * dt; + gx += gyro_bias[0]; // apply integral feedback + gy += gyro_bias[1]; + gz += gyro_bias[2]; + } + else { + gyro_bias[0] = 0.0f; // prevent integral windup + gyro_bias[1] = 0.0f; + gyro_bias[2] = 0.0f; + } + + // Apply proportional feedback + gx += twoKp * halfex; + gy += twoKp * halfey; + gz += twoKp * halfez; + } + + //! Integrate rate of change of quaternion +#if 0 + gx *= (0.5f * dt); // pre-multiply common factors + gy *= (0.5f * dt); + gz *= (0.5f * dt); +#endif + + // Time derivative of quaternion. q_dot = 0.5*q\otimes omega. + //! q_k = q_{k-1} + dt*\dot{q} + //! \dot{q} = 0.5*q \otimes P(\omega) + dq0 = 0.5f*(-q1 * gx - q2 * gy - q3 * gz); + dq1 = 0.5f*(q0 * gx + q2 * gz - q3 * gy); + dq2 = 0.5f*(q0 * gy - q1 * gz + q3 * gx); + dq3 = 0.5f*(q0 * gz + q1 * gy - q2 * gx); + + q0 += dt*dq0; + q1 += dt*dq1; + q2 += dt*dq2; + q3 += dt*dq3; + + // Normalise quaternion + recipNorm = invSqrt(q0 * q0 + q1 * q1 + q2 * q2 + q3 * q3); + q0 *= recipNorm; + q1 *= recipNorm; + q2 *= recipNorm; + q3 *= recipNorm; + + // Auxiliary variables to avoid repeated arithmetic + q0q0 = q0 * q0; + q0q1 = q0 * q1; + q0q2 = q0 * q2; + q0q3 = q0 * q3; + q1q1 = q1 * q1; + q1q2 = q1 * q2; + q1q3 = q1 * q3; + q2q2 = q2 * q2; + q2q3 = q2 * q3; + q3q3 = q3 * q3; +} + +void send_uart_byte(char c) +{ + write(uart,&c,1); +} + +void send_uart_bytes(uint8_t *data, int length) +{ + write(uart,data,(size_t)(sizeof(uint8_t)*length)); +} + +void send_uart_float(float f) { + uint8_t * b = (uint8_t *) &f; + + //! Assume float is 4-bytes + for(int i=0; i<4; i++) { + + uint8_t b1 = (b[i] >> 4) & 0x0f; + uint8_t b2 = (b[i] & 0x0f); + + uint8_t c1 = (b1 < 10) ? ('0' + b1) : 'A' + b1 - 10; + uint8_t c2 = (b2 < 10) ? ('0' + b2) : 'A' + b2 - 10; + + send_uart_bytes(&c1,1); + send_uart_bytes(&c2,1); + } +} + +void send_uart_float_arr(float *arr, int length) +{ + for(int i=0;i<length;++i) + { + send_uart_float(arr[i]); + send_uart_byte(','); + } +} + +int open_uart(int baud, const char *uart_name, struct termios *uart_config_original, bool *is_usb) +{ + int speed; + + switch (baud) { + case 0: speed = B0; break; + case 50: speed = B50; break; + case 75: speed = B75; break; + case 110: speed = B110; break; + case 134: speed = B134; break; + case 150: speed = B150; break; + case 200: speed = B200; break; + case 300: speed = B300; break; + case 600: speed = B600; break; + case 1200: speed = B1200; break; + case 1800: speed = B1800; break; + case 2400: speed = B2400; break; + case 4800: speed = B4800; break; + case 9600: speed = B9600; break; + case 19200: speed = B19200; break; + case 38400: speed = B38400; break; + case 57600: speed = B57600; break; + case 115200: speed = B115200; break; + case 230400: speed = B230400; break; + case 460800: speed = B460800; break; + case 921600: speed = B921600; break; + default: + printf("ERROR: Unsupported baudrate: %d\n\tsupported examples:\n\n\t9600\n19200\n38400\n57600\n115200\n230400\n460800\n921600\n\n", baud); + return -EINVAL; + } + + printf("[so3_comp_filt] UART is %s, baudrate is %d\n", uart_name, baud); + uart = open(uart_name, O_RDWR | O_NOCTTY); + + /* Try to set baud rate */ + struct termios uart_config; + int termios_state; + *is_usb = false; + + /* make some wild guesses including that USB serial is indicated by either /dev/ttyACM0 or /dev/console */ + if (strcmp(uart_name, "/dev/ttyACM0") != OK && strcmp(uart_name, "/dev/console") != OK) { + /* Back up the original uart configuration to restore it after exit */ + if ((termios_state = tcgetattr(uart, uart_config_original)) < 0) { + printf("ERROR getting baudrate / termios config for %s: %d\n", uart_name, termios_state); + close(uart); + return -1; + } + + /* Fill the struct for the new configuration */ + tcgetattr(uart, &uart_config); + + /* Clear ONLCR flag (which appends a CR for every LF) */ + uart_config.c_oflag &= ~ONLCR; + + /* Set baud rate */ + if (cfsetispeed(&uart_config, speed) < 0 || cfsetospeed(&uart_config, speed) < 0) { + printf("ERROR setting baudrate / termios config for %s: %d (cfsetispeed, cfsetospeed)\n", uart_name, termios_state); + close(uart); + return -1; + } + + + if ((termios_state = tcsetattr(uart, TCSANOW, &uart_config)) < 0) { + printf("ERROR setting baudrate / termios config for %s (tcsetattr)\n", uart_name); + close(uart); + return -1; + } + + } else { + *is_usb = true; + } + + return uart; +} + +/* + * [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_so3_comp_thread_main(int argc, char *argv[]) +{ + +const unsigned int loop_interval_alarm = 6500; // loop interval in microseconds + + //! Serial debug related + int ch; + struct termios uart_config_original; + bool usb_uart; + bool debug_mode = false; + char *device_name = "/dev/ttyS2"; + baudrate = 115200; + + //! Time constant + float dt = 0.005f; + + /* output euler angles */ + float euler[3] = {0.0f, 0.0f, 0.0f}; + + float Rot_matrix[9] = {1.f, 0, 0, + 0, 1.f, 0, + 0, 0, 1.f + }; /**< init: identity matrix */ + + float acc[3] = {0.0f, 0.0f, 0.0f}; + float gyro[3] = {0.0f, 0.0f, 0.0f}; + float mag[3] = {0.0f, 0.0f, 0.0f}; + + /* work around some stupidity in task_create's argv handling */ + argc -= 2; + argv += 2; + + //! -d <device_name>, default : /dev/ttyS2 + //! -b <baud_rate>, default : 115200 + while ((ch = getopt(argc,argv,"d:b:")) != EOF){ + switch(ch){ + case 'b': + baudrate = strtoul(optarg, NULL, 10); + if(baudrate == 0) + printf("invalid baud rate '%s'",optarg); + break; + case 'd': + device_name = optarg; + debug_mode = true; + break; + default: + usage("invalid argument"); + } + } + + if(debug_mode){ + printf("Opening debugging port for 3D visualization\n"); + uart = open_uart(baudrate, device_name, &uart_config_original, &usb_uart); + if (uart < 0) + printf("could not open %s", device_name); + else + printf("Open port success\n"); + } + + // print text + printf("Nonlinear SO3 Attitude Estimator initialized..\n\n"); + fflush(stdout); + + int overloadcounter = 19; + + /* 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)); + + //! Initialize attitude vehicle uORB message. + 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_so3_comp_params so3_comp_params; + struct attitude_estimator_so3_comp_param_handles so3_comp_param_handles; + + /* initialize parameter handles */ + parameters_init(&so3_comp_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 so3_comp_loop_perf = perf_alloc(PC_ELAPSED, "attitude_estimator_so3_comp"); + + /* Main loop*/ + while (!thread_should_exit) { + + struct pollfd fds[2]; + fds[0].fd = sub_raw; + fds[0].events = POLLIN; + fds[1].fd = sub_params; + fds[1].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 so3_comp] 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(&so3_comp_param_handles, &so3_comp_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(so3_comp_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; + } + + gyro[0] = raw.gyro_rad_s[0] - gyro_offsets[0]; + gyro[1] = raw.gyro_rad_s[1] - gyro_offsets[1]; + gyro[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; + } + + acc[0] = raw.accelerometer_m_s2[0]; + acc[1] = raw.accelerometer_m_s2[1]; + acc[2] = 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; + } + + mag[0] = raw.magnetometer_ga[0]; + mag[1] = raw.magnetometer_ga[1]; + mag[2] = 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(&so3_comp_param_handles, &so3_comp_params); + const_initialized = true; + } + + /* do not execute the filter if not initialized */ + if (!const_initialized) { + continue; + } + + uint64_t timing_start = hrt_absolute_time(); + + // NOTE : Accelerometer is reversed. + // Because proper mount of PX4 will give you a reversed accelerometer readings. + NonlinearSO3AHRSupdate(gyro[0],gyro[1],gyro[2],-acc[0],-acc[1],-acc[2],mag[0],mag[1],mag[2],so3_comp_params.Kp,so3_comp_params.Ki, dt); + + // Convert q->R. + Rot_matrix[0] = q0q0 + q1q1 - q2q2 - q3q3;// 11 + Rot_matrix[1] = 2.0 * (q1*q2 + q0*q3); // 12 + Rot_matrix[2] = 2.0 * (q1*q3 - q0*q2); // 13 + Rot_matrix[3] = 2.0 * (q1*q2 - q0*q3); // 21 + Rot_matrix[4] = q0q0 - q1q1 + q2q2 - q3q3;// 22 + Rot_matrix[5] = 2.0 * (q2*q3 + q0*q1); // 23 + Rot_matrix[6] = 2.0 * (q1*q3 + q0*q2); // 31 + Rot_matrix[7] = 2.0 * (q2*q3 - q0*q1); // 32 + Rot_matrix[8] = q0q0 - q1q1 - q2q2 + q3q3;// 33 + + //1-2-3 Representation. + //Equation (290) + //Representing Attitude: Euler Angles, Unit Quaternions, and Rotation Vectors, James Diebel. + // Existing PX4 EKF code was generated by MATLAB which uses coloum major order matrix. + euler[0] = atan2f(Rot_matrix[5], Rot_matrix[8]); //! Roll + euler[1] = -asinf(Rot_matrix[2]); //! Pitch + euler[2] = atan2f(Rot_matrix[1],Rot_matrix[0]); //! Yaw + + /* swap values for next iteration, check for fatal inputs */ + if (isfinite(euler[0]) && isfinite(euler[1]) && isfinite(euler[2])) { + /* Do something */ + } 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 so3_comp] 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] - so3_comp_params.roll_off; + att.pitch = euler[1] - so3_comp_params.pitch_off; + att.yaw = euler[2] - so3_comp_params.yaw_off; + + //! Euler angle rate. But it needs to be investigated again. + /* + att.rollspeed = 2.0f*(-q1*dq0 + q0*dq1 - q3*dq2 + q2*dq3); + att.pitchspeed = 2.0f*(-q2*dq0 + q3*dq1 + q0*dq2 - q1*dq3); + att.yawspeed = 2.0f*(-q3*dq0 -q2*dq1 + q1*dq2 + q0*dq3); + */ + att.rollspeed = gyro[0]; + att.pitchspeed = gyro[1]; + att.yawspeed = gyro[2]; + + att.rollacc = 0; + att.pitchacc = 0; + att.yawacc = 0; + + //! Quaternion + att.q[0] = q0; + att.q[1] = q1; + att.q[2] = q2; + att.q[3] = q3; + att.q_valid = true; + + /* TODO: Bias estimation required */ + memcpy(&att.rate_offsets, &(gyro_bias), 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(so3_comp_loop_perf); + + //! This will print out debug packet to visualization software + if(debug_mode) + { + float quat[4]; + quat[0] = q0; + quat[1] = q1; + quat[2] = q2; + quat[3] = q3; + send_uart_float_arr(quat,4); + send_uart_byte('\n'); + } + } + } + } + + loopcounter++; + }// while + + thread_running = false; + + /* Reset the UART flags to original state */ + if (!usb_uart) + tcsetattr(uart, TCSANOW, &uart_config_original); + + return 0; +} diff --git a/src/modules/attitude_estimator_so3_comp/attitude_estimator_so3_comp_params.c b/src/modules/attitude_estimator_so3_comp/attitude_estimator_so3_comp_params.c new file mode 100755 index 000000000..f962515df --- /dev/null +++ b/src/modules/attitude_estimator_so3_comp/attitude_estimator_so3_comp_params.c @@ -0,0 +1,63 @@ +/* + * Author: Hyon Lim <limhyon@gmail.com, hyonlim@snu.ac.kr> + * + * @file attitude_estimator_so3_comp_params.c + * + * Implementation of nonlinear complementary filters on the SO(3). + * This code performs attitude estimation by using accelerometer, gyroscopes and magnetometer. + * Result is provided as quaternion, 1-2-3 Euler angle and rotation matrix. + * + * Theory of nonlinear complementary filters on the SO(3) is based on [1]. + * Quaternion realization of [1] is based on [2]. + * Optmized quaternion update code is based on Sebastian Madgwick's implementation. + * + * References + * [1] Mahony, R.; Hamel, T.; Pflimlin, Jean-Michel, "Nonlinear Complementary Filters on the Special Orthogonal Group," Automatic Control, IEEE Transactions on , vol.53, no.5, pp.1203,1218, June 2008 + * [2] Euston, M.; Coote, P.; Mahony, R.; Jonghyuk Kim; Hamel, T., "A complementary filter for attitude estimation of a fixed-wing UAV," Intelligent Robots and Systems, 2008. IROS 2008. IEEE/RSJ International Conference on , vol., no., pp.340,345, 22-26 Sept. 2008 + */ + +#include "attitude_estimator_so3_comp_params.h" + +/* This is filter gain for nonlinear SO3 complementary filter */ +/* NOTE : How to tune the gain? First of all, stick with this default gain. And let the quad in stable place. + Log the steady state reponse of filter. If it is too slow, increase SO3_COMP_KP. + If you are flying from ground to high altitude in short amount of time, please increase SO3_COMP_KI which + will compensate gyro bias which depends on temperature and vibration of your vehicle */ +PARAM_DEFINE_FLOAT(SO3_COMP_KP, 1.0f); //! This parameter will give you about 15 seconds convergence time. + //! You can set this gain higher if you want more fast response. + //! But note that higher gain will give you also higher overshoot. +PARAM_DEFINE_FLOAT(SO3_COMP_KI, 0.05f); //! This gain will incorporate slow time-varying bias (e.g., temperature change) + //! This gain is depend on your vehicle status. + +/* offsets in roll, pitch and yaw of sensor plane and body */ +PARAM_DEFINE_FLOAT(ATT_ROLL_OFFS, 0.0f); +PARAM_DEFINE_FLOAT(ATT_PITCH_OFFS, 0.0f); +PARAM_DEFINE_FLOAT(ATT_YAW_OFFS, 0.0f); + +int parameters_init(struct attitude_estimator_so3_comp_param_handles *h) +{ + /* Filter gain parameters */ + h->Kp = param_find("SO3_COMP_KP"); + h->Ki = param_find("SO3_COMP_KI"); + + /* Attitude offset (WARNING: Do not change if you do not know what exactly this variable wil lchange) */ + h->roll_off = param_find("ATT_ROLL_OFFS"); + h->pitch_off = param_find("ATT_PITCH_OFFS"); + h->yaw_off = param_find("ATT_YAW_OFFS"); + + return OK; +} + +int parameters_update(const struct attitude_estimator_so3_comp_param_handles *h, struct attitude_estimator_so3_comp_params *p) +{ + /* Update filter gain */ + param_get(h->Kp, &(p->Kp)); + param_get(h->Ki, &(p->Ki)); + + /* Update attitude offset */ + param_get(h->roll_off, &(p->roll_off)); + param_get(h->pitch_off, &(p->pitch_off)); + param_get(h->yaw_off, &(p->yaw_off)); + + return OK; +} diff --git a/src/modules/attitude_estimator_so3_comp/attitude_estimator_so3_comp_params.h b/src/modules/attitude_estimator_so3_comp/attitude_estimator_so3_comp_params.h new file mode 100755 index 000000000..f00695630 --- /dev/null +++ b/src/modules/attitude_estimator_so3_comp/attitude_estimator_so3_comp_params.h @@ -0,0 +1,44 @@ +/* + * Author: Hyon Lim <limhyon@gmail.com, hyonlim@snu.ac.kr> + * + * @file attitude_estimator_so3_comp_params.h + * + * Implementation of nonlinear complementary filters on the SO(3). + * This code performs attitude estimation by using accelerometer, gyroscopes and magnetometer. + * Result is provided as quaternion, 1-2-3 Euler angle and rotation matrix. + * + * Theory of nonlinear complementary filters on the SO(3) is based on [1]. + * Quaternion realization of [1] is based on [2]. + * Optmized quaternion update code is based on Sebastian Madgwick's implementation. + * + * References + * [1] Mahony, R.; Hamel, T.; Pflimlin, Jean-Michel, "Nonlinear Complementary Filters on the Special Orthogonal Group," Automatic Control, IEEE Transactions on , vol.53, no.5, pp.1203,1218, June 2008 + * [2] Euston, M.; Coote, P.; Mahony, R.; Jonghyuk Kim; Hamel, T., "A complementary filter for attitude estimation of a fixed-wing UAV," Intelligent Robots and Systems, 2008. IROS 2008. IEEE/RSJ International Conference on , vol., no., pp.340,345, 22-26 Sept. 2008 + */ + +#include <systemlib/param/param.h> + +struct attitude_estimator_so3_comp_params { + float Kp; + float Ki; + float roll_off; + float pitch_off; + float yaw_off; +}; + +struct attitude_estimator_so3_comp_param_handles { + param_t Kp, Ki; + param_t roll_off, pitch_off, yaw_off; +}; + +/** + * Initialize all parameter handles and values + * + */ +int parameters_init(struct attitude_estimator_so3_comp_param_handles *h); + +/** + * Update all parameters + * + */ +int parameters_update(const struct attitude_estimator_so3_comp_param_handles *h, struct attitude_estimator_so3_comp_params *p); diff --git a/src/modules/attitude_estimator_so3_comp/module.mk b/src/modules/attitude_estimator_so3_comp/module.mk new file mode 100644 index 000000000..92f43d920 --- /dev/null +++ b/src/modules/attitude_estimator_so3_comp/module.mk @@ -0,0 +1,8 @@ +# +# Attitude estimator (Nonlinear SO3 complementary Filter) +# + +MODULE_COMMAND = attitude_estimator_so3_comp + +SRCS = attitude_estimator_so3_comp_main.cpp \ + attitude_estimator_so3_comp_params.c |