ekf2: expand accel bias stability criteria

This commit is contained in:
Daniel Agar
2021-11-17 15:02:35 -05:00
parent 846f807eff
commit 170849c8f8
5 changed files with 73 additions and 52 deletions
+59 -30
View File
@@ -1057,17 +1057,18 @@ void EKF2::PublishOdometryAligned(const hrt_abstime &timestamp, const vehicle_od
void EKF2::PublishSensorBias(const hrt_abstime &timestamp)
{
// estimator_sensor_bias
estimator_sensor_bias_s bias{};
bias.timestamp_sample = _ekf.get_imu_sample_delayed().time_us;
const Vector3f gyro_bias{_ekf.getGyroBias()};
const Vector3f accel_bias{_ekf.getAccelBias()};
const Vector3f mag_bias{_ekf.getMagBias()};
// only publish on change
// publish at ~1 Hz, or sooner if there's a change
if ((gyro_bias - _last_gyro_bias_published).longerThan(0.001f)
|| (accel_bias - _last_accel_bias_published).longerThan(0.001f)
|| (mag_bias - _last_mag_bias_published).longerThan(0.001f)) {
|| (mag_bias - _last_mag_bias_published).longerThan(0.001f)
|| (timestamp >= _last_sensor_bias_published + 1_s)) {
estimator_sensor_bias_s bias{};
bias.timestamp_sample = timestamp;
// take device ids from sensor_selection_s if not using specific vehicle_imu_s
if (_device_id_gyro != 0) {
@@ -1102,6 +1103,8 @@ void EKF2::PublishSensorBias(const hrt_abstime &timestamp)
bias.timestamp = _replay_mode ? timestamp : hrt_absolute_time();
_estimator_sensor_bias_pub.publish(bias);
_last_sensor_bias_published = bias.timestamp;
}
}
@@ -1779,18 +1782,40 @@ void EKF2::UpdateRangeSample(ekf2_timestamps_s &ekf2_timestamps)
void EKF2::UpdateAccelCalibration(const hrt_abstime &timestamp)
{
if (_param_ekf2_aid_mask.get() & MASK_INHIBIT_ACC_BIAS) {
_accel_cal.cal_available = false;
return;
}
// State variance assumed for accelerometer bias storage.
// This is a reference variance used to calculate the fraction of learned accelerometer bias that will be used to update the stored value.
// Larger values cause a larger fraction of the learned biases to be used.
static constexpr float max_var_allowed = 1e-3f;
static constexpr float max_var_ratio = 1e2f;
const Vector3f bias_variance{_ekf.getAccelBiasVariance()};
// Check if conditions are OK for learning of accelerometer bias values
// the EKF is operating in the correct mode and there are no filter faults
if (_ekf.control_status_flags().in_air && (_ekf.fault_status().value == 0)
&& !(_param_ekf2_aid_mask.get() & MASK_INHIBIT_ACC_BIAS)) {
if ((_ekf.fault_status().value == 0)
&& !_ekf.accel_bias_inhibited()
&& !_preflt_checker.hasHorizFailed() && !_preflt_checker.hasVertFailed()
&& (_ekf.control_status_flags().baro_hgt || _ekf.control_status_flags().rng_hgt
|| _ekf.control_status_flags().gps_hgt || _ekf.control_status_flags().ev_hgt)
&& !_ekf.warning_event_flags().height_sensor_timeout && !_ekf.warning_event_flags().invalid_accel_bias_cov_reset
&& !_ekf.innov_check_fail_status_flags().reject_ver_pos && !_ekf.innov_check_fail_status_flags().reject_ver_vel
&& (bias_variance.max() < max_var_allowed) && (bias_variance.max() < max_var_ratio * bias_variance.min())
) {
if (_accel_cal.last_us != 0) {
_accel_cal.total_time_us += timestamp - _accel_cal.last_us;
// Start checking accel bias estimates when we have accumulated sufficient calibration time
if (_accel_cal.total_time_us > 30_s) {
_accel_cal.last_bias = _ekf.getAccelBias();
_accel_cal.last_bias_variance = _ekf.getAccelBiasVariance();
if (!_accel_cal.cal_available) {
PX4_DEBUG("%d accel bias now stable", _instance);
}
_accel_cal.cal_available = true;
}
}
@@ -1798,31 +1823,40 @@ void EKF2::UpdateAccelCalibration(const hrt_abstime &timestamp)
_accel_cal.last_us = timestamp;
} else {
// conditions are NOT OK for learning accelerometer bias, reset timestamp
// but keep the accumulated calibration time
_accel_cal.last_us = 0;
if (_ekf.fault_status().value != 0) {
// if a filter fault has occurred, assume previous learning was invalid and do not
// count it towards total learning time.
_accel_cal.total_time_us = 0;
// conditions are NOT OK for learning accelerometer bias, reset
if (_accel_cal.total_time_us > 0) {
PX4_DEBUG("%d, clearing learned accel bias", _instance);
}
_accel_cal = {};
}
}
void EKF2::UpdateGyroCalibration(const hrt_abstime &timestamp)
{
// State variance assumed for accelerometer bias storage.
// This is a reference variance used to calculate the fraction of learned accelerometer bias that will be used to update the stored value.
// Larger values cause a larger fraction of the learned biases to be used.
static constexpr float max_var_allowed = 1e-3f;
static constexpr float max_var_ratio = 1e2f;
const Vector3f bias_variance{_ekf.getGyroBiasVariance()};
// Check if conditions are OK for learning of gyro bias values
// the EKF is operating in the correct mode and there are no filter faults
if (_ekf.control_status_flags().in_air && (_ekf.fault_status().value == 0)) {
if ((_ekf.fault_status().value == 0)
&& (bias_variance.max() < max_var_allowed) && (bias_variance.max() < max_var_ratio * bias_variance.min())
) {
if (_gyro_cal.last_us != 0) {
_gyro_cal.total_time_us += timestamp - _gyro_cal.last_us;
// Start checking gyro bias estimates when we have accumulated sufficient calibration time
if (_gyro_cal.total_time_us > 30_s) {
_gyro_cal.last_bias = _ekf.getGyroBias();
_gyro_cal.last_bias_variance = _ekf.getGyroBiasVariance();
if (!_gyro_cal.cal_available) {
PX4_DEBUG("%d gyro bias now stable", _instance);
}
_gyro_cal.cal_available = true;
}
}
@@ -1830,15 +1864,12 @@ void EKF2::UpdateGyroCalibration(const hrt_abstime &timestamp)
_gyro_cal.last_us = timestamp;
} else {
// conditions are NOT OK for learning gyro bias, reset timestamp
// but keep the accumulated calibration time
_gyro_cal.last_us = 0;
if (_ekf.fault_status().value != 0) {
// if a filter fault has occurred, assume previous learning was invalid and do not
// count it towards total learning time.
_gyro_cal.total_time_us = 0;
// conditions are NOT OK for learning gyro bias, reset
if (_gyro_cal.total_time_us > 0) {
PX4_DEBUG("%d, clearing learned gyro bias", _instance);
}
_gyro_cal = {};
}
}
@@ -1853,8 +1884,6 @@ void EKF2::UpdateMagCalibration(const hrt_abstime &timestamp)
// Start checking mag bias estimates when we have accumulated sufficient calibration time
if (_mag_cal.total_time_us > 30_s) {
_mag_cal.last_bias = _ekf.getMagBias();
_mag_cal.last_bias_variance = _ekf.getMagBiasVariance();
_mag_cal.cal_available = true;
}
}