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 <drivers/drv_airspeed.h>
#include <uORB/topics/differential_pressure.h>
#include <systemlib/mavlink_log.h>
#include <parameters/param.h>
#include <systemlib/err.h>

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)
{
	int result = PX4_OK;
	unsigned calibration_counter = 0;
	const unsigned maxcount = 2400;

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

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

	int diff_pres_sub = orb_subscribe(ORB_ID(differential_pressure));
	struct differential_pressure_s diff_pres;

	float diff_pres_offset = 0.0f;

	/* Reset sensor parameters */
	struct airspeed_scale airscale = {
		diff_pres_offset,
		1.0f,
	};

	bool paramreset_successful = false;
	int  fd = px4_open(AIRSPEED0_DEVICE_PATH, 0);

	if (fd > 0) {
		if (PX4_OK == px4_ioctl(fd, AIRSPEEDIOCSSCALE, (long unsigned int)&airscale)) {
			paramreset_successful = true;

		} else {
			calibration_log_critical(mavlink_log_pub, "[cal] airspeed offset zero failed");
		}

		px4_close(fd);
	}

	int cancel_sub = calibrate_cancel_subscribe();

	if (!paramreset_successful) {

		/* only warn if analog scaling is zero */
		float analog_scaling = 0.0f;
		param_get(param_find("SENS_DPRES_ANSC"), &(analog_scaling));

		if (fabsf(analog_scaling) < 0.1f) {
			calibration_log_critical(mavlink_log_pub, "[cal] No airspeed sensor found");
			goto error_return;
		}

		/* set scaling offset parameter */
		if (param_set(param_find("SENS_DPRES_OFF"), &(diff_pres_offset))) {
			calibration_log_critical(mavlink_log_pub, CAL_ERROR_SET_PARAMS_MSG);
			goto error_return;
		}
	}

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

	while (calibration_counter < calibration_count) {

		if (calibrate_cancel_check(mavlink_log_pub, cancel_sub)) {
			goto error_return;
		}

		/* wait blocking for new data */
		px4_pollfd_struct_t fds[1];
		fds[0].fd = diff_pres_sub;
		fds[0].events = POLLIN;

		int poll_ret = px4_poll(fds, 1, 1000);

		if (poll_ret) {
			orb_copy(ORB_ID(differential_pressure), diff_pres_sub, &diff_pres);

			diff_pres_offset += diff_pres.differential_pressure_raw_pa;
			calibration_counter++;

			/* any differential pressure failure a reason to abort */
			if (diff_pres.error_count != 0) {
				calibration_log_critical(mavlink_log_pub, "[cal] Airspeed sensor is reporting errors (%" PRIu64 ")",
							 diff_pres.error_count);
				calibration_log_critical(mavlink_log_pub, "[cal] Check your wiring before trying again");
				feedback_calibration_failed(mavlink_log_pub);
				goto error_return;
			}

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

		} else if (poll_ret == 0) {
			/* any poll failure for 1s is a reason to abort */
			feedback_calibration_failed(mavlink_log_pub);
			goto error_return;
		}
	}

	diff_pres_offset = diff_pres_offset / calibration_count;

	if (PX4_ISFINITE(diff_pres_offset)) {

		int fd_scale = px4_open(AIRSPEED0_DEVICE_PATH, 0);
		airscale.offset_pa = diff_pres_offset;

		if (fd_scale > 0) {
			if (PX4_OK != px4_ioctl(fd_scale, AIRSPEEDIOCSSCALE, (long unsigned int)&airscale)) {
				calibration_log_critical(mavlink_log_pub, "[cal] airspeed offset update failed");
			}

			px4_close(fd_scale);
		}

		// 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);
			goto error_return;
		}

	} else {
		feedback_calibration_failed(mavlink_log_pub);
		goto error_return;
	}

	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 across front of pitot without touching");

	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, cancel_sub)) {
			goto error_return;
		}

		/* wait blocking for new data */
		px4_pollfd_struct_t fds[1];
		fds[0].fd = diff_pres_sub;
		fds[0].events = POLLIN;

		int poll_ret = px4_poll(fds, 1, 1000);

		if (poll_ret) {
			orb_copy(ORB_ID(differential_pressure), diff_pres_sub, &diff_pres);

			if (fabsf(diff_pres.differential_pressure_filtered_pa) > 50.0f) {
				if (diff_pres.differential_pressure_filtered_pa > 0) {
					calibration_log_info(mavlink_log_pub, "[cal] Positive pressure: OK (%d Pa)",
							     (int)diff_pres.differential_pressure_filtered_pa);
					break;

				} else {
					/* do not allow negative values */
					calibration_log_critical(mavlink_log_pub, "[cal] Negative pressure difference detected (%d Pa)",
								 (int)diff_pres.differential_pressure_filtered_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);
						goto error_return;
					}

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

					feedback_calibration_failed(mavlink_log_pub);
					goto error_return;
				}
			}

			if (calibration_counter % 500 == 0) {
				calibration_log_info(mavlink_log_pub, "[cal] Create air pressure! (got %d, wanted: 50 Pa)",
						     (int)diff_pres.differential_pressure_filtered_pa);
				tune_neutral(true);
			}

			calibration_counter++;

		} else if (poll_ret == 0) {
			/* any poll failure for 1s is a reason to abort */
			feedback_calibration_failed(mavlink_log_pub);
			goto error_return;
		}
	}

	if (calibration_counter == maxcount) {
		feedback_calibration_failed(mavlink_log_pub);
		goto error_return;
	}

	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);

	/* Wait 2sec for the airflow to stop and ensure the driver filter has caught up, otherwise
	 * the followup preflight checks might fail. */
	px4_usleep(2e6);

normal_return:
	calibrate_cancel_unsubscribe(cancel_sub);
	px4_close(diff_pres_sub);

	// This give a chance for the log messages to go out of the queue before someone else stomps on then
	px4_sleep(1);

	return result;

error_return:
	result = PX4_ERROR;
	goto normal_return;
}