estimated IMU bias preflight checks

- commander preflightcheck use estimator_sensor_bias message instead of EKF state index magic number
 - ekf2 publish estimated bias limits in estimator_sensor_bias
 - preflightcheck only error if bias estimate exceeds half of configured limit (delete COM_ARM_EKF_AB and COM_ARM_EKF_GB parameters)
This commit is contained in:
Daniel Agar 2021-01-07 13:23:59 -05:00 committed by Lorenz Meier
parent 7c95e99156
commit 48f125f150
10 changed files with 51 additions and 70 deletions

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@ -98,7 +98,6 @@ then
param set BAT_V_DIV 10.14
param set BAT_A_PER_V 18.18
#param set CBRK_IO_SAFETY 22027
param set COM_ARM_EKF_AB 0.005
param set COM_DISARM_LAND 2
# Filter settings

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@ -77,7 +77,6 @@ then
param set BAT_SOURCE 0
param set CBRK_IO_SAFETY 22027
#param set COM_ARM_EKF_AB 0.005
#param set COM_DISARM_LAND 3
# Filter settings

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@ -107,7 +107,6 @@ then
param set BAT_V_DIV 10.14
param set BAT_A_PER_V 18.18
#param set CBRK_IO_SAFETY 22027
param set COM_ARM_EKF_AB 0.005
param set COM_DISARM_LAND 2
# Filter settings

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@ -49,7 +49,6 @@ then
# sensor calibration
param set CAL_MAG_SIDES 63
param set SENS_BOARD_ROT 0
param set COM_ARM_EKF_AB 0.0032
# circuit breakers
param set CBRK_IO_SAFETY 22027

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@ -3,22 +3,25 @@
# scale errors, in-run bias and thermal drift (if thermal compensation is enabled and available).
#
uint64 timestamp # time since system start (microseconds)
uint64 timestamp # time since system start (microseconds)
uint64 timestamp_sample # the timestamp of the raw data (microseconds)
# In-run bias estimates (subtract from uncorrected data)
uint32 gyro_device_id # unique device ID for the sensor that does not change between power cycles
float32[3] gyro_bias # gyroscope in-run bias in body frame (rad/s)
uint32 gyro_device_id # unique device ID for the sensor that does not change between power cycles
float32[3] gyro_bias # gyroscope in-run bias in body frame (rad/s)
float32 gyro_bias_limit # magnitude of maximum gyroscope in-run bias in body frame (rad/s)
float32[3] gyro_bias_variance
bool gyro_bias_valid
uint32 accel_device_id # unique device ID for the sensor that does not change between power cycles
float32[3] accel_bias # accelerometer in-run bias in body frame (m/s^2)
uint32 accel_device_id # unique device ID for the sensor that does not change between power cycles
float32[3] accel_bias # accelerometer in-run bias in body frame (m/s^2)
float32 accel_bias_limit # magnitude of maximum accelerometer in-run bias in body frame (m/s^2)
float32[3] accel_bias_variance
bool accel_bias_valid
uint32 mag_device_id # unique device ID for the sensor that does not change between power cycles
float32[3] mag_bias # magnetometer in-run bias in body frame (Gauss)
uint32 mag_device_id # unique device ID for the sensor that does not change between power cycles
float32[3] mag_bias # magnetometer in-run bias in body frame (Gauss)
float32 mag_bias_limit # magnitude of maximum magnetometer in-run bias in body frame (Gauss)
float32[3] mag_bias_variance
bool mag_bias_valid

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@ -232,7 +232,7 @@ bool PreFlightCheck::preflightCheck(orb_advert_t *mavlink_log_pub, vehicle_statu
failed = true;
}
if (!ekf2CheckStates(mavlink_log_pub, report_failures && report_ekf_fail)) {
if (!ekf2CheckSensorBias(mavlink_log_pub, report_failures && report_ekf_fail)) {
failed = true;
}
}

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@ -111,7 +111,7 @@ private:
static bool ekf2Check(orb_advert_t *mavlink_log_pub, vehicle_status_s &vehicle_status, const bool optional,
const bool report_fail, const bool enforce_gps_required);
static bool ekf2CheckStates(orb_advert_t *mavlink_log_pub, const bool report_fail);
static bool ekf2CheckSensorBias(orb_advert_t *mavlink_log_pub, const bool report_fail);
static bool failureDetectorCheck(orb_advert_t *mavlink_log_pub, const vehicle_status_s &status, const bool report_fail,
const bool prearm);

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@ -39,9 +39,11 @@
#include <systemlib/mavlink_log.h>
#include <uORB/Subscription.hpp>
#include <uORB/topics/estimator_selector_status.h>
#include <uORB/topics/estimator_states.h>
#include <uORB/topics/estimator_sensor_bias.h>
#include <uORB/topics/estimator_status.h>
using namespace time_literals;
bool PreFlightCheck::ekf2Check(orb_advert_t *mavlink_log_pub, vehicle_status_s &vehicle_status, const bool optional,
const bool report_fail, const bool enforce_gps_required)
{
@ -69,7 +71,6 @@ bool PreFlightCheck::ekf2Check(orb_advert_t *mavlink_log_pub, vehicle_status_s &
// Get estimator status data if available and exit with a fail recorded if not
uORB::SubscriptionData<estimator_selector_status_s> estimator_selector_status_sub{ORB_ID(estimator_selector_status)};
uORB::SubscriptionData<estimator_status_s> status_sub{ORB_ID(estimator_status), estimator_selector_status_sub.get().primary_instance};
status_sub.update();
const estimator_status_s &status = status_sub.get();
if (status.timestamp == 0) {
@ -231,52 +232,55 @@ out:
return success;
}
bool PreFlightCheck::ekf2CheckStates(orb_advert_t *mavlink_log_pub, const bool report_fail)
bool PreFlightCheck::ekf2CheckSensorBias(orb_advert_t *mavlink_log_pub, const bool report_fail)
{
float ekf_ab_test_limit = 1.0f; // pass limit re-used for each test
param_get(param_find("COM_ARM_EKF_AB"), &ekf_ab_test_limit);
float ekf_gb_test_limit = 1.0f; // pass limit re-used for each test
param_get(param_find("COM_ARM_EKF_GB"), &ekf_gb_test_limit);
// Get estimator states data if available and exit with a fail recorded if not
uORB::SubscriptionData<estimator_selector_status_s> estimator_selector_status_sub{ORB_ID(estimator_selector_status)};
uORB::Subscription states_sub{ORB_ID(estimator_states), estimator_selector_status_sub.get().primary_instance};
uORB::SubscriptionData<estimator_sensor_bias_s> estimator_sensor_bias_sub{ORB_ID(estimator_sensor_bias), estimator_selector_status_sub.get().primary_instance};
const estimator_sensor_bias_s &bias = estimator_sensor_bias_sub.get();
estimator_states_s states;
if (hrt_elapsed_time(&bias.timestamp) < 30_s) {
if (states_sub.copy(&states)) {
// check accelerometer bias estimates
if (bias.accel_bias_valid) {
const float ekf_ab_test_limit = 0.5f * bias.accel_bias_limit;
// check accelerometer delta velocity bias estimates
for (uint8_t index = 13; index < 16; index++) {
// allow for higher uncertainty in estimates for axes that are less observable to prevent false positives
// adjust test threshold by 3-sigma
float test_uncertainty = 3.0f * sqrtf(fmaxf(states.covariances[index], 0.0f));
for (uint8_t axis_index = 0; axis_index < 3; axis_index++) {
// allow for higher uncertainty in estimates for axes that are less observable to prevent false positives
// adjust test threshold by 3-sigma
const float test_uncertainty = 3.0f * sqrtf(fmaxf(bias.accel_bias_variance[axis_index], 0.0f));
if (fabsf(states.states[index]) > ekf_ab_test_limit + test_uncertainty) {
if (fabsf(bias.accel_bias[axis_index]) > ekf_ab_test_limit + test_uncertainty) {
if (report_fail) {
PX4_ERR("accel bias (axis %d): |%.8f| > %.8f + %.8f", axis_index,
(double)bias.accel_bias[axis_index], (double)ekf_ab_test_limit, (double)test_uncertainty);
mavlink_log_critical(mavlink_log_pub, "Preflight Fail: High Accelerometer Bias");
}
if (report_fail) {
PX4_ERR("state %d: |%.8f| > %.8f + %.8f", index, (double)states.states[index], (double)ekf_ab_test_limit,
(double)test_uncertainty);
mavlink_log_critical(mavlink_log_pub, "Preflight Fail: High Accelerometer Bias");
return false;
}
return false;
}
}
// check gyro delta angle bias estimates
// check gyro bias estimates
if (bias.gyro_bias_valid) {
const float ekf_gb_test_limit = 0.5f * bias.gyro_bias_limit;
for (uint8_t axis_index = 0; axis_index < 3; axis_index++) {
// allow for higher uncertainty in estimates for axes that are less observable to prevent false positives
// adjust test threshold by 3-sigma
const float test_uncertainty = 3.0f * sqrtf(fmaxf(bias.gyro_bias_variance[axis_index], 0.0f));
if (fabsf(states.states[10]) > ekf_gb_test_limit
|| fabsf(states.states[11]) > ekf_gb_test_limit
|| fabsf(states.states[12]) > ekf_gb_test_limit) {
if (fabsf(bias.gyro_bias[axis_index]) > ekf_gb_test_limit + test_uncertainty) {
if (report_fail) {
PX4_ERR("gyro bias (axis %d): |%.8f| > %.8f + %.8f", axis_index,
(double)bias.gyro_bias[axis_index], (double)ekf_gb_test_limit, (double)test_uncertainty);
mavlink_log_critical(mavlink_log_pub, "Preflight Fail: High Gyro Bias");
}
if (report_fail) {
mavlink_log_critical(mavlink_log_pub, "Preflight Fail: High Gyro Bias");
return false;
}
}
return false;
}
}

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@ -556,31 +556,6 @@ PARAM_DEFINE_FLOAT(COM_ARM_EKF_HGT, 1.0f);
*/
PARAM_DEFINE_FLOAT(COM_ARM_EKF_YAW, 0.5f);
/**
* Maximum value of EKF accelerometer delta velocity bias estimate that will allow arming.
* Note: ekf2 will limit the delta velocity bias estimate magnitude to be less than EKF2_ABL_LIM * FILTER_UPDATE_PERIOD_MS * 0.001 so this parameter must be less than that to be useful.
*
* @group Commander
* @unit m/s
* @min 0.001
* @max 0.01
* @decimal 4
* @increment 0.0001
*/
PARAM_DEFINE_FLOAT(COM_ARM_EKF_AB, 0.0022f);
/**
* Maximum value of EKF gyro delta angle bias estimate that will allow arming
*
* @group Commander
* @unit rad
* @min 0.0001
* @max 0.0017
* @decimal 4
* @increment 0.0001
*/
PARAM_DEFINE_FLOAT(COM_ARM_EKF_GB, 0.0011f);
/**
* Maximum accelerometer inconsistency between IMU units that will allow arming
*

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@ -884,6 +884,7 @@ void EKF2::PublishSensorBias(const hrt_abstime &timestamp)
if (_device_id_gyro != 0) {
bias.gyro_device_id = _device_id_gyro;
gyro_bias.copyTo(bias.gyro_bias);
bias.gyro_bias_limit = math::radians(20.f); // 20 degrees/s see Ekf::constrainStates()
_ekf.getGyroBiasVariance().copyTo(bias.gyro_bias_variance);
bias.gyro_bias_valid = true;
@ -893,6 +894,7 @@ void EKF2::PublishSensorBias(const hrt_abstime &timestamp)
if ((_device_id_accel != 0) && !(_param_ekf2_aid_mask.get() & MASK_INHIBIT_ACC_BIAS)) {
bias.accel_device_id = _device_id_accel;
accel_bias.copyTo(bias.accel_bias);
bias.accel_bias_limit = _params->acc_bias_lim;
_ekf.getAccelBiasVariance().copyTo(bias.accel_bias_variance);
bias.accel_bias_valid = !_ekf.fault_status_flags().bad_acc_bias;
@ -902,6 +904,7 @@ void EKF2::PublishSensorBias(const hrt_abstime &timestamp)
if (_device_id_mag != 0) {
bias.mag_device_id = _device_id_mag;
mag_bias.copyTo(bias.mag_bias);
bias.mag_bias_limit = 0.5f; // 0.5 Gauss see Ekf::constrainStates()
_mag_cal_last_bias_variance.copyTo(bias.mag_bias_variance);
bias.mag_bias_valid = _mag_cal_available;