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https://gitee.com/mirrors_PX4/PX4-Autopilot.git
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moved commander to C++, preparation for better gyro scale calibration respecting the current attitude for more accurate results
This commit is contained in:
Lorenz Meier
@@ -0,0 +1,464 @@
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/****************************************************************************
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*
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* Copyright (C) 2013 PX4 Development Team. All rights reserved.
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* Author: Anton Babushkin <anton.babushkin@me.com>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name PX4 nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/**
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* @file accelerometer_calibration.cpp
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*
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* Implementation of accelerometer calibration.
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*
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* Transform acceleration vector to true orientation, scale and offset
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*
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* ===== Model =====
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* accel_corr = accel_T * (accel_raw - accel_offs)
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*
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* accel_corr[3] - fully corrected acceleration vector in body frame
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* accel_T[3][3] - accelerometers transform matrix, rotation and scaling transform
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* accel_raw[3] - raw acceleration vector
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* accel_offs[3] - acceleration offset vector
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*
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* ===== Calibration =====
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*
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* Reference vectors
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* accel_corr_ref[6][3] = [ g 0 0 ] // nose up
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* | -g 0 0 | // nose down
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* | 0 g 0 | // left side down
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* | 0 -g 0 | // right side down
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* | 0 0 g | // on back
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* [ 0 0 -g ] // level
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* accel_raw_ref[6][3]
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*
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* accel_corr_ref[i] = accel_T * (accel_raw_ref[i] - accel_offs), i = 0...5
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*
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* 6 reference vectors * 3 axes = 18 equations
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* 9 (accel_T) + 3 (accel_offs) = 12 unknown constants
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*
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* Find accel_offs
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*
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* accel_offs[i] = (accel_raw_ref[i*2][i] + accel_raw_ref[i*2+1][i]) / 2
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*
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* Find accel_T
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*
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* 9 unknown constants
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* need 9 equations -> use 3 of 6 measurements -> 3 * 3 = 9 equations
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*
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* accel_corr_ref[i*2] = accel_T * (accel_raw_ref[i*2] - accel_offs), i = 0...2
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*
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* Solve separate system for each row of accel_T:
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*
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* accel_corr_ref[j*2][i] = accel_T[i] * (accel_raw_ref[j*2] - accel_offs), j = 0...2
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*
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* A * x = b
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*
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* x = [ accel_T[0][i] ]
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* | accel_T[1][i] |
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* [ accel_T[2][i] ]
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*
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* b = [ accel_corr_ref[0][i] ] // One measurement per axis is enough
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* | accel_corr_ref[2][i] |
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* [ accel_corr_ref[4][i] ]
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*
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* a[i][j] = accel_raw_ref[i][j] - accel_offs[j], i = 0;2;4, j = 0...2
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*
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* Matrix A is common for all three systems:
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* A = [ a[0][0] a[0][1] a[0][2] ]
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* | a[2][0] a[2][1] a[2][2] |
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* [ a[4][0] a[4][1] a[4][2] ]
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*
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* x = A^-1 * b
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*
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* accel_T = A^-1 * g
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* g = 9.80665
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*
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* @author Anton Babushkin <anton.babushkin@me.com>
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*/
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#include "accelerometer_calibration.h"
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#include "commander_helper.h"
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#include <unistd.h>
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#include <stdio.h>
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#include <poll.h>
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#include <fcntl.h>
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#include <sys/prctl.h>
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#include <math.h>
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#include <string.h>
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#include <drivers/drv_hrt.h>
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#include <uORB/topics/sensor_combined.h>
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#include <drivers/drv_accel.h>
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#include <systemlib/conversions.h>
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#include <systemlib/param/param.h>
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#include <systemlib/err.h>
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#include <mavlink/mavlink_log.h>
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/* oddly, ERROR is not defined for c++ */
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#ifdef ERROR
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# undef ERROR
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#endif
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static const int ERROR = -1;
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int do_accel_calibration_measurements(int mavlink_fd, float accel_offs[3], float accel_scale[3]);
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int detect_orientation(int mavlink_fd, int sub_sensor_combined);
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int read_accelerometer_avg(int sensor_combined_sub, float accel_avg[3], int samples_num);
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int mat_invert3(float src[3][3], float dst[3][3]);
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int calculate_calibration_values(float accel_ref[6][3], float accel_T[3][3], float accel_offs[3], float g);
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void do_accel_calibration(int mavlink_fd) {
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/* announce change */
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mavlink_log_info(mavlink_fd, "accel calibration started");
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/* measure and calculate offsets & scales */
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float accel_offs[3];
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float accel_scale[3];
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int res = do_accel_calibration_measurements(mavlink_fd, accel_offs, accel_scale);
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if (res == OK) {
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/* measurements complete successfully, set parameters */
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if (param_set(param_find("SENS_ACC_XOFF"), &(accel_offs[0]))
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|| param_set(param_find("SENS_ACC_YOFF"), &(accel_offs[1]))
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|| param_set(param_find("SENS_ACC_ZOFF"), &(accel_offs[2]))
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|| param_set(param_find("SENS_ACC_XSCALE"), &(accel_scale[0]))
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|| param_set(param_find("SENS_ACC_YSCALE"), &(accel_scale[1]))
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|| param_set(param_find("SENS_ACC_ZSCALE"), &(accel_scale[2]))) {
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mavlink_log_critical(mavlink_fd, "ERROR: setting offs or scale failed");
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}
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int fd = open(ACCEL_DEVICE_PATH, 0);
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struct accel_scale ascale = {
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accel_offs[0],
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accel_scale[0],
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accel_offs[1],
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accel_scale[1],
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accel_offs[2],
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accel_scale[2],
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};
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if (OK != ioctl(fd, ACCELIOCSSCALE, (long unsigned int)&ascale))
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warn("WARNING: failed to set scale / offsets for accel");
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close(fd);
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/* auto-save to EEPROM */
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int save_ret = param_save_default();
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if (save_ret != 0) {
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warn("WARNING: auto-save of params to storage failed");
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}
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mavlink_log_info(mavlink_fd, "accel calibration done");
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tune_positive();
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} else {
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/* measurements error */
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mavlink_log_info(mavlink_fd, "accel calibration aborted");
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tune_negative();
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}
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/* exit accel calibration mode */
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}
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int do_accel_calibration_measurements(int mavlink_fd, float accel_offs[3], float accel_scale[3]) {
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const int samples_num = 2500;
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float accel_ref[6][3];
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bool data_collected[6] = { false, false, false, false, false, false };
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const char *orientation_strs[6] = { "x+", "x-", "y+", "y-", "z+", "z-" };
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/* reset existing calibration */
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int fd = open(ACCEL_DEVICE_PATH, 0);
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struct accel_scale ascale_null = {
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0.0f,
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1.0f,
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0.0f,
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1.0f,
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0.0f,
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1.0f,
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};
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int ioctl_res = ioctl(fd, ACCELIOCSSCALE, (long unsigned int)&ascale_null);
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close(fd);
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if (OK != ioctl_res) {
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warn("ERROR: failed to set scale / offsets for accel");
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return ERROR;
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}
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int sensor_combined_sub = orb_subscribe(ORB_ID(sensor_combined));
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while (true) {
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bool done = true;
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char str[80];
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int str_ptr;
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str_ptr = sprintf(str, "keep vehicle still:");
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for (int i = 0; i < 6; i++) {
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if (!data_collected[i]) {
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str_ptr += sprintf(&(str[str_ptr]), " %s", orientation_strs[i]);
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done = false;
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}
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}
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if (done)
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break;
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mavlink_log_info(mavlink_fd, str);
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int orient = detect_orientation(mavlink_fd, sensor_combined_sub);
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if (orient < 0)
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return ERROR;
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sprintf(str, "meas started: %s", orientation_strs[orient]);
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mavlink_log_info(mavlink_fd, str);
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read_accelerometer_avg(sensor_combined_sub, &(accel_ref[orient][0]), samples_num);
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str_ptr = sprintf(str, "meas result for %s: [ %.2f %.2f %.2f ]", orientation_strs[orient],
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(double)accel_ref[orient][0],
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(double)accel_ref[orient][1],
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(double)accel_ref[orient][2]);
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mavlink_log_info(mavlink_fd, str);
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data_collected[orient] = true;
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tune_neutral();
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}
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close(sensor_combined_sub);
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/* calculate offsets and rotation+scale matrix */
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float accel_T[3][3];
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int res = calculate_calibration_values(accel_ref, accel_T, accel_offs, CONSTANTS_ONE_G);
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if (res != 0) {
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mavlink_log_info(mavlink_fd, "ERROR: calibration values calc error");
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return ERROR;
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}
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/* convert accel transform matrix to scales,
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* rotation part of transform matrix is not used by now
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*/
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for (int i = 0; i < 3; i++) {
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accel_scale[i] = accel_T[i][i];
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}
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return OK;
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}
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/*
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* Wait for vehicle become still and detect it's orientation.
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*
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* @return 0..5 according to orientation when vehicle is still and ready for measurements,
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* ERROR if vehicle is not still after 30s or orientation error is more than 5m/s^2
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*/
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int detect_orientation(int mavlink_fd, int sub_sensor_combined) {
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struct sensor_combined_s sensor;
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/* exponential moving average of accel */
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float accel_ema[3] = { 0.0f, 0.0f, 0.0f };
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/* max-hold dispersion of accel */
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float accel_disp[3] = { 0.0f, 0.0f, 0.0f };
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/* EMA time constant in seconds*/
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float ema_len = 0.2f;
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/* set "still" threshold to 0.1 m/s^2 */
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float still_thr2 = pow(0.1f, 2);
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/* set accel error threshold to 5m/s^2 */
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float accel_err_thr = 5.0f;
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/* still time required in us */
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int64_t still_time = 2000000;
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struct pollfd fds[1];
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fds[0].fd = sub_sensor_combined;
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fds[0].events = POLLIN;
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hrt_abstime t_start = hrt_absolute_time();
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/* set timeout to 30s */
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hrt_abstime timeout = 30000000;
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hrt_abstime t_timeout = t_start + timeout;
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hrt_abstime t = t_start;
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hrt_abstime t_prev = t_start;
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hrt_abstime t_still = 0;
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unsigned poll_errcount = 0;
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while (true) {
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/* wait blocking for new data */
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int poll_ret = poll(fds, 1, 1000);
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if (poll_ret) {
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orb_copy(ORB_ID(sensor_combined), sub_sensor_combined, &sensor);
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t = hrt_absolute_time();
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float dt = (t - t_prev) / 1000000.0f;
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t_prev = t;
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float w = dt / ema_len;
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for (int i = 0; i < 3; i++) {
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accel_ema[i] = accel_ema[i] * (1.0f - w) + sensor.accelerometer_m_s2[i] * w;
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float d = (float) sensor.accelerometer_m_s2[i] - accel_ema[i];
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d = d * d;
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accel_disp[i] = accel_disp[i] * (1.0f - w);
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if (d > accel_disp[i])
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accel_disp[i] = d;
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}
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/* still detector with hysteresis */
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if ( accel_disp[0] < still_thr2 &&
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accel_disp[1] < still_thr2 &&
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accel_disp[2] < still_thr2 ) {
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/* is still now */
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if (t_still == 0) {
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/* first time */
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mavlink_log_info(mavlink_fd, "still...");
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t_still = t;
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t_timeout = t + timeout;
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} else {
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/* still since t_still */
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if ((int64_t) t - (int64_t) t_still > still_time) {
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/* vehicle is still, exit from the loop to detection of its orientation */
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break;
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}
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}
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} else if ( accel_disp[0] > still_thr2 * 2.0f ||
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accel_disp[1] > still_thr2 * 2.0f ||
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accel_disp[2] > still_thr2 * 2.0f) {
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/* not still, reset still start time */
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if (t_still != 0) {
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mavlink_log_info(mavlink_fd, "moving...");
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t_still = 0;
|
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}
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}
|
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} else if (poll_ret == 0) {
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poll_errcount++;
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}
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if (t > t_timeout) {
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poll_errcount++;
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}
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if (poll_errcount > 1000) {
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mavlink_log_info(mavlink_fd, "ERROR: failed reading accel");
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return -1;
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}
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}
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if ( fabsf(accel_ema[0] - CONSTANTS_ONE_G) < accel_err_thr &&
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fabsf(accel_ema[1]) < accel_err_thr &&
|
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fabsf(accel_ema[2]) < accel_err_thr )
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return 0; // [ g, 0, 0 ]
|
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if ( fabsf(accel_ema[0] + CONSTANTS_ONE_G) < accel_err_thr &&
|
||||
fabsf(accel_ema[1]) < accel_err_thr &&
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fabsf(accel_ema[2]) < accel_err_thr )
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return 1; // [ -g, 0, 0 ]
|
||||
if ( fabsf(accel_ema[0]) < accel_err_thr &&
|
||||
fabsf(accel_ema[1] - CONSTANTS_ONE_G) < accel_err_thr &&
|
||||
fabsf(accel_ema[2]) < accel_err_thr )
|
||||
return 2; // [ 0, g, 0 ]
|
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if ( fabsf(accel_ema[0]) < accel_err_thr &&
|
||||
fabsf(accel_ema[1] + CONSTANTS_ONE_G) < accel_err_thr &&
|
||||
fabsf(accel_ema[2]) < accel_err_thr )
|
||||
return 3; // [ 0, -g, 0 ]
|
||||
if ( fabsf(accel_ema[0]) < accel_err_thr &&
|
||||
fabsf(accel_ema[1]) < accel_err_thr &&
|
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fabsf(accel_ema[2] - CONSTANTS_ONE_G) < accel_err_thr )
|
||||
return 4; // [ 0, 0, g ]
|
||||
if ( fabsf(accel_ema[0]) < accel_err_thr &&
|
||||
fabsf(accel_ema[1]) < accel_err_thr &&
|
||||
fabsf(accel_ema[2] + CONSTANTS_ONE_G) < accel_err_thr )
|
||||
return 5; // [ 0, 0, -g ]
|
||||
|
||||
mavlink_log_info(mavlink_fd, "ERROR: invalid orientation");
|
||||
|
||||
return -2; // Can't detect orientation
|
||||
}
|
||||
|
||||
/*
|
||||
* Read specified number of accelerometer samples, calculate average and dispersion.
|
||||
*/
|
||||
int read_accelerometer_avg(int sensor_combined_sub, float accel_avg[3], int samples_num) {
|
||||
struct pollfd fds[1];
|
||||
fds[0].fd = sensor_combined_sub;
|
||||
fds[0].events = POLLIN;
|
||||
int count = 0;
|
||||
float accel_sum[3] = { 0.0f, 0.0f, 0.0f };
|
||||
|
||||
while (count < samples_num) {
|
||||
int poll_ret = poll(fds, 1, 1000);
|
||||
if (poll_ret == 1) {
|
||||
struct sensor_combined_s sensor;
|
||||
orb_copy(ORB_ID(sensor_combined), sensor_combined_sub, &sensor);
|
||||
for (int i = 0; i < 3; i++)
|
||||
accel_sum[i] += sensor.accelerometer_m_s2[i];
|
||||
count++;
|
||||
} else {
|
||||
return ERROR;
|
||||
}
|
||||
}
|
||||
|
||||
for (int i = 0; i < 3; i++) {
|
||||
accel_avg[i] = accel_sum[i] / count;
|
||||
}
|
||||
|
||||
return OK;
|
||||
}
|
||||
|
||||
int mat_invert3(float src[3][3], float dst[3][3]) {
|
||||
float det = src[0][0] * (src[1][1] * src[2][2] - src[1][2] * src[2][1]) -
|
||||
src[0][1] * (src[1][0] * src[2][2] - src[1][2] * src[2][0]) +
|
||||
src[0][2] * (src[1][0] * src[2][1] - src[1][1] * src[2][0]);
|
||||
if (det == 0.0f)
|
||||
return ERROR; // Singular matrix
|
||||
|
||||
dst[0][0] = (src[1][1] * src[2][2] - src[1][2] * src[2][1]) / det;
|
||||
dst[1][0] = (src[1][2] * src[2][0] - src[1][0] * src[2][2]) / det;
|
||||
dst[2][0] = (src[1][0] * src[2][1] - src[1][1] * src[2][0]) / det;
|
||||
dst[0][1] = (src[0][2] * src[2][1] - src[0][1] * src[2][2]) / det;
|
||||
dst[1][1] = (src[0][0] * src[2][2] - src[0][2] * src[2][0]) / det;
|
||||
dst[2][1] = (src[0][1] * src[2][0] - src[0][0] * src[2][1]) / det;
|
||||
dst[0][2] = (src[0][1] * src[1][2] - src[0][2] * src[1][1]) / det;
|
||||
dst[1][2] = (src[0][2] * src[1][0] - src[0][0] * src[1][2]) / det;
|
||||
dst[2][2] = (src[0][0] * src[1][1] - src[0][1] * src[1][0]) / det;
|
||||
|
||||
return OK;
|
||||
}
|
||||
|
||||
int calculate_calibration_values(float accel_ref[6][3], float accel_T[3][3], float accel_offs[3], float g) {
|
||||
/* calculate offsets */
|
||||
for (int i = 0; i < 3; i++) {
|
||||
accel_offs[i] = (accel_ref[i * 2][i] + accel_ref[i * 2 + 1][i]) / 2;
|
||||
}
|
||||
|
||||
/* fill matrix A for linear equations system*/
|
||||
float mat_A[3][3];
|
||||
memset(mat_A, 0, sizeof(mat_A));
|
||||
for (int i = 0; i < 3; i++) {
|
||||
for (int j = 0; j < 3; j++) {
|
||||
float a = accel_ref[i * 2][j] - accel_offs[j];
|
||||
mat_A[i][j] = a;
|
||||
}
|
||||
}
|
||||
|
||||
/* calculate inverse matrix for A */
|
||||
float mat_A_inv[3][3];
|
||||
if (mat_invert3(mat_A, mat_A_inv) != OK)
|
||||
return ERROR;
|
||||
|
||||
/* copy results to accel_T */
|
||||
for (int i = 0; i < 3; i++) {
|
||||
for (int j = 0; j < 3; j++) {
|
||||
/* simplify matrices mult because b has only one non-zero element == g at index i */
|
||||
accel_T[j][i] = mat_A_inv[j][i] * g;
|
||||
}
|
||||
}
|
||||
|
||||
return OK;
|
||||
}
|
||||
Reference in New Issue
Block a user