PX4-Autopilot/src/modules/commander/airspeed_calibration.cpp

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/**
 * @file airspeed_calibration.cpp
 * Airspeed sensor calibration routine
 */

#include "airspeed_calibration.h"
#include "calibration_messages.h"
#include "calibration_routines.h"
#include "commander_helper.h"

#include <px4_platform_common/defines.h>
#include <px4_platform_common/posix.h>
#include <px4_platform_common/time.h>
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <math.h>
#include <drivers/drv_hrt.h>
#include <uORB/Subscription.hpp>
#include <uORB/topics/differential_pressure.h>
#include <systemlib/mavlink_log.h>
#include <parameters/param.h>
#include <systemlib/err.h>

using namespace time_literals;

static const char *sensor_name = "airspeed";

static void feedback_calibration_failed(orb_advert_t *mavlink_log_pub)
{
	px4_sleep(5);
	calibration_log_critical(mavlink_log_pub, CAL_QGC_FAILED_MSG, sensor_name);
}

int do_airspeed_calibration(orb_advert_t *mavlink_log_pub)
{
	const hrt_abstime calibration_started = hrt_absolute_time();

	int result = PX4_OK;
	unsigned calibration_counter = 0;
	const unsigned maxcount = 500;

	/* give directions */
	calibration_log_info(mavlink_log_pub, CAL_QGC_STARTED_MSG, sensor_name);

	const unsigned calibration_count = (maxcount * 2) / 3;

	float diff_pres_offset = 0.0f;

	calibration_log_critical(mavlink_log_pub, "[cal] Ensure sensor is not measuring wind");
	px4_usleep(500 * 1000);

	uORB::SubscriptionData<differential_pressure_s> diff_pres_sub{ORB_ID(differential_pressure)};

	while (calibration_counter < calibration_count) {

		if (calibrate_cancel_check(mavlink_log_pub, calibration_started)) {
			return PX4_ERROR;
		}

		if (diff_pres_sub.update()) {

			const differential_pressure_s &diff_pres = diff_pres_sub.get();

			diff_pres_offset += diff_pres.differential_pressure_pa;
			calibration_counter++;

			if (calibration_counter % (calibration_count / 20) == 0) {
				calibration_log_info(mavlink_log_pub, CAL_QGC_PROGRESS_MSG, (calibration_counter * 80) / calibration_count);
			}
		}

		if (hrt_elapsed_time(&calibration_started) > 30_s) {
			feedback_calibration_failed(mavlink_log_pub);
			return PX4_ERROR;
		}

		px4_usleep(10000);
	}

	diff_pres_offset = diff_pres_offset / calibration_count;

	if (PX4_ISFINITE(diff_pres_offset)) {
		// Prevent a completely zero param
		// since this is used to detect a missing calibration
		// This value is numerically down in the noise and has
		// no effect on the sensor performance.
		if (fabsf(diff_pres_offset) < 0.00000001f) {
			diff_pres_offset = 0.00000001f;
		}

		if (param_set(param_find("SENS_DPRES_OFF"), &diff_pres_offset)) {
			calibration_log_critical(mavlink_log_pub, CAL_ERROR_SET_PARAMS_MSG);
			return PX4_ERROR;
		}

	} else {
		feedback_calibration_failed(mavlink_log_pub);
		return PX4_ERROR;
	}

	calibration_log_info(mavlink_log_pub, "[cal] Offset of %d Pascal", (int)diff_pres_offset);

	/* wait 500 ms to ensure parameter propagated through the system */
	px4_usleep(500 * 1000);

	calibration_log_critical(mavlink_log_pub, "[cal] Blow into front of pitot without touching");

	float differential_pressure_sum = 0.f;
	int differential_pressure_sum_count = 0;

	calibration_counter = 0;

	/* just take a few samples and make sure pitot tubes are not reversed, timeout after ~30 seconds */
	while (calibration_counter < maxcount) {

		if (calibrate_cancel_check(mavlink_log_pub, calibration_started)) {
			return PX4_ERROR;
		}

		if (diff_pres_sub.update()) {
			const differential_pressure_s &diff_pres = diff_pres_sub.get();

			differential_pressure_sum += diff_pres.differential_pressure_pa;
			differential_pressure_sum_count++;

			const float differential_pressure_pa = (differential_pressure_sum / differential_pressure_sum_count) - diff_pres_offset;

			if ((differential_pressure_sum_count > 10) && (fabsf(differential_pressure_pa) > 50.f)) {
				if (differential_pressure_pa > 0) {
					calibration_log_info(mavlink_log_pub, "[cal] Positive pressure: OK (%d Pa)", (int)differential_pressure_pa);
					break;

				} else {
					/* do not allow negative values */
					calibration_log_critical(mavlink_log_pub, "[cal] Negative pressure difference detected (%d Pa)",
								 (int)differential_pressure_pa);
					calibration_log_critical(mavlink_log_pub, "[cal] Swap static and dynamic ports!");

					/* the user setup is wrong, wipe the calibration to force a proper re-calibration */
					diff_pres_offset = 0.0f;

					if (param_set(param_find("SENS_DPRES_OFF"), &(diff_pres_offset))) {
						calibration_log_critical(mavlink_log_pub, CAL_ERROR_SET_PARAMS_MSG);
						return PX4_ERROR;
					}

					/* save */
					calibration_log_info(mavlink_log_pub, CAL_QGC_PROGRESS_MSG, 0);
					param_save_default();

					feedback_calibration_failed(mavlink_log_pub);
					return PX4_ERROR;
				}
			}

			if (calibration_counter % 300 == 0) {
				calibration_log_info(mavlink_log_pub, "[cal] Create air pressure! (got %d, wanted: 50 Pa)",
						     (int)differential_pressure_pa);
				tune_neutral(true);

				// reset average
				differential_pressure_sum = 0.f;
				differential_pressure_sum_count = 0;
			}

			calibration_counter++;
		}

		if (hrt_elapsed_time(&calibration_started) > 90_s) {
			feedback_calibration_failed(mavlink_log_pub);
			return PX4_ERROR;
		}

		px4_usleep(10000);
	}

	if (calibration_counter == maxcount) {
		feedback_calibration_failed(mavlink_log_pub);
		return PX4_ERROR;
	}

	calibration_log_info(mavlink_log_pub, CAL_QGC_PROGRESS_MSG, 100);

	calibration_log_info(mavlink_log_pub, CAL_QGC_DONE_MSG, sensor_name);
	tune_neutral(true);

	// This give a chance for the log messages to go out of the queue before someone else stomps on then
	px4_usleep(200000);

	return result;
}