mirror of https://github.com/ArduPilot/ardupilot
156 lines
5.4 KiB
C++
156 lines
5.4 KiB
C++
/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
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#include "Copter.h"
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/**
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*
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* ekf_check.pde - detects failures of the ekf or inertial nav system
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* triggers an alert to the pilot and helps take countermeasures
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*
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*/
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#ifndef EKF_CHECK_ITERATIONS_MAX
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# define EKF_CHECK_ITERATIONS_MAX 10 // 1 second (ie. 10 iterations at 10hz) of bad variances signals a failure
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#endif
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#ifndef EKF_CHECK_WARNING_TIME
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# define EKF_CHECK_WARNING_TIME (30*1000) // warning text messages are sent to ground no more than every 30 seconds
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#endif
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////////////////////////////////////////////////////////////////////////////////
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// EKF_check strucutre
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////////////////////////////////////////////////////////////////////////////////
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static struct {
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uint8_t fail_count; // number of iterations ekf or dcm have been out of tolerances
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uint8_t bad_variance : 1; // true if ekf should be considered untrusted (fail_count has exceeded EKF_CHECK_ITERATIONS_MAX)
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uint32_t last_warn_time; // system time of last warning in milliseconds. Used to throttle text warnings sent to GCS
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} ekf_check_state;
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// ekf_check - detects if ekf variance are out of tolerance and triggers failsafe
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// should be called at 10hz
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void Copter::ekf_check()
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{
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// return immediately if motors are not armed, ekf check is disabled, not using ekf or usb is connected
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if (!motors.armed() || ap.usb_connected || (g.ekfcheck_thresh <= 0.0f)) {
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ekf_check_state.fail_count = 0;
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ekf_check_state.bad_variance = false;
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AP_Notify::flags.ekf_bad = ekf_check_state.bad_variance;
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failsafe_ekf_off_event(); // clear failsafe
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return;
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}
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// compare compass and velocity variance vs threshold
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if (ekf_over_threshold()) {
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// if compass is not yet flagged as bad
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if (!ekf_check_state.bad_variance) {
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// increase counter
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ekf_check_state.fail_count++;
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// if counter above max then trigger failsafe
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if (ekf_check_state.fail_count >= EKF_CHECK_ITERATIONS_MAX) {
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// limit count from climbing too high
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ekf_check_state.fail_count = EKF_CHECK_ITERATIONS_MAX;
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ekf_check_state.bad_variance = true;
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// log an error in the dataflash
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Log_Write_Error(ERROR_SUBSYSTEM_EKFCHECK, ERROR_CODE_EKFCHECK_BAD_VARIANCE);
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// send message to gcs
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if ((hal.scheduler->millis() - ekf_check_state.last_warn_time) > EKF_CHECK_WARNING_TIME) {
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gcs_send_text_P(SEVERITY_HIGH,PSTR("EKF variance"));
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ekf_check_state.last_warn_time = hal.scheduler->millis();
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}
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failsafe_ekf_event();
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}
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}
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} else {
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// reduce counter
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if (ekf_check_state.fail_count > 0) {
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ekf_check_state.fail_count--;
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// if compass is flagged as bad and the counter reaches zero then clear flag
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if (ekf_check_state.bad_variance && ekf_check_state.fail_count == 0) {
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ekf_check_state.bad_variance = false;
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// log recovery in the dataflash
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Log_Write_Error(ERROR_SUBSYSTEM_EKFCHECK, ERROR_CODE_EKFCHECK_VARIANCE_CLEARED);
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// clear failsafe
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failsafe_ekf_off_event();
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}
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}
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}
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// set AP_Notify flags
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AP_Notify::flags.ekf_bad = ekf_check_state.bad_variance;
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// To-Do: add ekf variances to extended status
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}
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// ekf_over_threshold - returns true if the ekf's variance are over the tolerance
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bool Copter::ekf_over_threshold()
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{
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#if AP_AHRS_NAVEKF_AVAILABLE
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// return false immediately if disabled
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if (g.ekfcheck_thresh <= 0.0f) {
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return false;
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}
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// return true immediately if position is bad
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if (!position_ok() && !optflow_position_ok()) {
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return true;
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}
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// use EKF to get variance
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float posVar, hgtVar, tasVar;
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Vector3f magVar;
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Vector2f offset;
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float compass_variance;
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float vel_variance;
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ahrs.get_NavEKF().getVariances(vel_variance, posVar, hgtVar, magVar, tasVar, offset);
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compass_variance = magVar.length();
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// return true if compass and velocity variance over the threshold
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return (compass_variance >= g.ekfcheck_thresh && vel_variance >= g.ekfcheck_thresh);
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#else
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return false;
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#endif
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}
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// failsafe_ekf_event - perform ekf failsafe
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void Copter::failsafe_ekf_event()
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{
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// return immediately if ekf failsafe already triggered
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if (failsafe.ekf) {
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return;
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}
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// do nothing if motors disarmed or not in flight mode that requires GPS
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if (!motors.armed() || !mode_requires_GPS(control_mode)) {
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return;
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}
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// EKF failsafe event has occurred
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failsafe.ekf = true;
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Log_Write_Error(ERROR_SUBSYSTEM_FAILSAFE_EKFINAV, ERROR_CODE_FAILSAFE_OCCURRED);
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// take action based on flight mode
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if (mode_requires_GPS(control_mode)) {
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set_mode_land_with_pause();
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}
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// if flight mode is LAND ensure it's not the GPS controlled LAND
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if (control_mode == LAND) {
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land_do_not_use_GPS();
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}
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}
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// failsafe_ekf_off_event - actions to take when EKF failsafe is cleared
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void Copter::failsafe_ekf_off_event(void)
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{
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// return immediately if not in ekf failsafe
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if (!failsafe.ekf) {
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return;
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}
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// clear flag and log recovery
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failsafe.ekf = false;
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Log_Write_Error(ERROR_SUBSYSTEM_FAILSAFE_EKFINAV, ERROR_CODE_FAILSAFE_RESOLVED);
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}
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