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Copter: add DCM check of yaw error 

Triggers an "ekf" failsafe if the DCM yaw error is > 60deg
This commit is contained in:
Randy Mackay 2014-10-16 16:18:37 +09:00
parent 470fcc2077
commit 7e1c975c54
2 changed files with 63 additions and 27 deletions
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4
ArduCopter/ArduCopter.pde
View File

@ -807,7 +807,7 @@ static const AP_Scheduler::Task scheduler_tasks[] PROGMEM = {
#endif
{ update_notify, 8, 10 },
{ one_hz_loop, 400, 42 },
{ ekf_check, 40, 2 },
{ ekf_dcm_check, 40, 2 },
{ crash_check, 40, 2 },
{ gcs_check_input, 8, 550 },
{ gcs_send_heartbeat, 400, 150 },
@ -875,7 +875,7 @@ static const AP_Scheduler::Task scheduler_tasks[] PROGMEM = {
#endif
{ update_notify, 2, 100 },
{ one_hz_loop, 100, 420 },
{ ekf_check, 10, 20 },
{ ekf_dcm_check, 10, 20 },
{ crash_check, 10, 20 },
{ gcs_check_input, 2, 550 },
{ gcs_send_heartbeat, 100, 150 },

86
ArduCopter/ekf_check.pde
View File

@ -15,42 +15,48 @@
# define EKF_CHECK_WARNING_TIME (30*1000) // warning text messages are sent to ground no more than every 30 seconds
#endif
// Enumerator for types of check
enum EKFCheckType {
CHECK_NONE = 0,
CHECK_DCM = 1,
CHECK_EKF = 2
};
////////////////////////////////////////////////////////////////////////////////
// EKF_check strucutre
////////////////////////////////////////////////////////////////////////////////
static struct {
uint8_t fail_count_compass; // number of iterations ekf's compass variance has been out of tolerances
uint8_t fail_count_compass; // number of iterations ekf or dcm have been out of tolerances
uint8_t bad_compass : 1; // true if compass variance is bad
uint8_t bad_compass : 1; // true if dcm or ekf should be considered untrusted (fail_count_compass has exceeded EKF_CHECK_ITERATIONS_MAX)
uint32_t last_warn_time; // system time of last warning in milliseconds. Used to throttle text warnings sent to GCS
} ekf_check_state;
// ekf_check - detects ekf variances that are out of tolerance
// ekf_dcm_check - detects if ekf variances or dcm yaw errors that are out of tolerance and triggers failsafe
// should be called at 10hz
void ekf_check()
void ekf_dcm_check()
{
#if AP_AHRS_NAVEKF_AVAILABLE
EKFCheckType check_type = CHECK_NONE;
// decide if we should check ekf or dcm
if (ahrs.have_inertial_nav() && g.ekfcheck_thresh > 0.0f) {
check_type = CHECK_EKF;
} else if (g.dcmcheck_thresh > 0.0f) {
check_type = CHECK_DCM;
}
// return immediately if motors are not armed, ekf check is disabled, not using ekf or usb is connected
if (!motors.armed() || g.ekfcheck_thresh == 0.0f || !ahrs.have_inertial_nav() || ap.usb_connected) {
if (!motors.armed() || ap.usb_connected || check_type == CHECK_NONE) {
ekf_check_state.fail_count_compass = 0;
ekf_check_state.bad_compass = 0;
ekf_check_state.bad_compass = false;
AP_Notify::flags.ekf_bad = ekf_check_state.bad_compass;
failsafe_ekf_off_event(); // clear failsafe
return;
}
// use EKF to get variance
float posVar, hgtVar, tasVar;
Vector3f magVar;
Vector2f offset;
float compass_variance;
float vel_variance;
ahrs.get_NavEKF().getVariances(vel_variance, posVar, hgtVar, magVar, tasVar, offset);
compass_variance = magVar.length();
// compare compass and velocity variance vs threshold
if (compass_variance >= g.ekfcheck_thresh && vel_variance > g.ekfcheck_thresh) {
if ((check_type == CHECK_EKF && ekf_over_threshold()) || (check_type == CHECK_DCM && dcm_over_threshold())) {
// if compass is not yet flagged as bad
if (!ekf_check_state.bad_compass) {
// increase counter
@ -64,7 +70,11 @@ void ekf_check()
Log_Write_Error(ERROR_SUBSYSTEM_EKFINAV_CHECK, ERROR_CODE_EKFINAV_CHECK_BAD_VARIANCE);
// send message to gcs
if ((hal.scheduler->millis() - ekf_check_state.last_warn_time) > EKF_CHECK_WARNING_TIME) {
gcs_send_text_P(SEVERITY_HIGH,PSTR("EKF variance"));
if (check_type == CHECK_EKF) {
gcs_send_text_P(SEVERITY_HIGH,PSTR("EKF variance"));
} else {
gcs_send_text_P(SEVERITY_HIGH,PSTR("DCM bad heading"));
}
ekf_check_state.last_warn_time = hal.scheduler->millis();
}
failsafe_ekf_event();
@ -90,19 +100,46 @@ void ekf_check()
AP_Notify::flags.ekf_bad = ekf_check_state.bad_compass;
// To-Do: add ekf variances to extended status
}
// dcm_over_threshold - returns true if the dcm yaw error is over the tolerance
static bool dcm_over_threshold()
{
// return true if yaw error is over the threshold
return (g.dcmcheck_thresh > 0.0f && ahrs.get_error_yaw() > g.dcmcheck_thresh);
}
// ekf_over_threshold - returns true if the ekf's variance are over the tolerance
static bool ekf_over_threshold()
{
#if AP_AHRS_NAVEKF_AVAILABLE
// return false immediately if disabled
if (g.ekfcheck_thresh <= 0.0f) {
return false;
}
// use EKF to get variance
float posVar, hgtVar, tasVar;
Vector3f magVar;
Vector2f offset;
float compass_variance;
float vel_variance;
ahrs.get_NavEKF().getVariances(vel_variance, posVar, hgtVar, magVar, tasVar, offset);
compass_variance = magVar.length();
// return true if compass and velocity variance over the threshold
return (compass_variance >= g.ekfcheck_thresh && vel_variance >= g.ekfcheck_thresh);
#else
// if no EKF available then never trigger failure
ekf_check_state.bad_compass = 0;
failsafe.ekf = false;
return false;
#endif
}
#if AP_AHRS_NAVEKF_AVAILABLE
// failsafe_ekf_event - perform ekf failsafe
static void failsafe_ekf_event()
{
// return immediately if ekf failsafe already triggered or disabled
if (failsafe.ekf || g.ekfcheck_thresh <= 0.0f) {
// return immediately if ekf failsafe already triggered
if (failsafe.ekf) {
return;
}
@ -138,4 +175,3 @@ static void failsafe_ekf_off_event(void)
failsafe.ekf = false;
Log_Write_Error(ERROR_SUBSYSTEM_FAILSAFE_EKFINAV, ERROR_CODE_FAILSAFE_RESOLVED);
}
#endif