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Code Issues Releases Activity

Move accel filter to separate function, for cleaner code and easier filter alteration.

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Optimize for filter disabled case (AccelTau = 0.0).
This commit is contained in:
Erik Gustavsson 2012-11-06 20:17:10 +01:00
parent 677f921b15
commit 104c61a174
1 changed files with 39 additions and 21 deletions
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60
flight/Modules/Attitude/attitude.c
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@ -87,7 +87,9 @@ static void settingsUpdatedCb(UAVObjEvent * objEv);
static float accelKi = 0;
static float accelKp = 0;
static float accel_alpha = 0;
static float accel_alpha_setting = 0;
static bool accel_filter_enabled = false;
static float accels_filtered[3];
static float grot_filtered[3];
static float yawBiasRate = 0;
static float gyroGain = 0.42;
static int16_t accelbias[3];
@ -217,21 +219,22 @@ static void AttitudeTask(void *parameters)
accelKp = 1;
accelKi = 0.9;
yawBiasRate = 0.23;
accel_alpha = 0;
accel_filter_enabled = false;
init = 0;
}
else if (zero_during_arming && (flightStatus.Armed == FLIGHTSTATUS_ARMED_ARMING)) {
accelKp = 1;
accelKi = 0.9;
yawBiasRate = 0.23;
accel_alpha = 0;
accel_filter_enabled = false;
init = 0;
} else if (init == 0) {
// Reload settings (all the rates)
AttitudeSettingsAccelKiGet(&accelKi);
AttitudeSettingsAccelKpGet(&accelKp);
AttitudeSettingsYawBiasRateGet(&yawBiasRate);
accel_alpha = accel_alpha_setting;
if(accel_alpha > 0.0f)
accel_filter_enabled = true;
init = 1;
}
@ -435,6 +438,19 @@ static int32_t updateSensorsCC3D(AccelsData * accelsData, GyrosData * gyrosData)
return 0;
}
static inline void apply_accel_filter(const float * raw, float * filtered)
{
if(accel_filter_enabled) {
filtered[0] = filtered[0] * accel_alpha + raw[0] * (1 - accel_alpha);
filtered[1] = filtered[1] * accel_alpha + raw[1] * (1 - accel_alpha);
filtered[2] = filtered[2] * accel_alpha + raw[2] * (1 - accel_alpha);
} else {
filtered[0] = raw[0];
filtered[1] = raw[1];
filtered[2] = raw[2];
}
}
static void updateAttitude(AccelsData * accelsData, GyrosData * gyrosData)
{
float dT;
@ -448,21 +464,20 @@ static void updateAttitude(AccelsData * accelsData, GyrosData * gyrosData)
float * gyros = &gyrosData->x;
float * accels = &accelsData->x;
static float grot[3];
float grot[3];
float accel_err[3];
// Apply smoothing to accel values, to reduce vibration noise before main calculations.
static float accels_filtered[3];
apply_accel_filter(accels,accels_filtered);
accels_filtered[0] = accels_filtered[0] * accel_alpha + accels[0] * (1 - accel_alpha);
accels_filtered[1] = accels_filtered[1] * accel_alpha + accels[1] * (1 - accel_alpha);
accels_filtered[2] = accels_filtered[2] * accel_alpha + accels[2] * (1 - accel_alpha);
// Rotate gravity to body frame, filter and cross with accels
grot[0] = -(2 * (q[1] * q[3] - q[0] * q[2]));
grot[1] = -(2 * (q[2] * q[3] + q[0] * q[1]));
grot[2] = -(q[0] * q[0] - q[1]*q[1] - q[2]*q[2] + q[3]*q[3]);
apply_accel_filter(grot,grot_filtered);
// Rotate gravity to body frame and cross with accels
grot[0] = grot[0] * accel_alpha - (2 * (q[1] * q[3] - q[0] * q[2])) * (1 - accel_alpha);
grot[1] = grot[1] * accel_alpha - (2 * (q[2] * q[3] + q[0] * q[1])) * (1 - accel_alpha);
grot[2] = grot[2] * accel_alpha - (q[0] * q[0] - q[1]*q[1] - q[2]*q[2] + q[3]*q[3]) * (1 - accel_alpha);
CrossProduct((const float *) accels_filtered, (const float *) grot, accel_err);
CrossProduct((const float *) accels_filtered, (const float *) grot_filtered, accel_err);
// Account for accel magnitude
float accel_mag = sqrtf(accels_filtered[0]*accels_filtered[0] + accels_filtered[1]*accels_filtered[1] + accels_filtered[2]*accels_filtered[2]);
@ -470,7 +485,9 @@ static void updateAttitude(AccelsData * accelsData, GyrosData * gyrosData)
return;
// Account for filtered gravity vector magnitude
float grot_mag = sqrtf(grot[0]*grot[0] + grot[1]*grot[1] + grot[2]*grot[2]);
float grot_mag;
if(accel_filter_enabled) grot_mag = sqrtf(grot[0]*grot[0] + grot[1]*grot[1] + grot[2]*grot[2]);
else grot_mag = 1.0f;
if(grot_mag < 1.0e-3f)
return;
@ -551,13 +568,14 @@ static void settingsUpdatedCb(UAVObjEvent * objEv) {
// Calculate accel filter alpha, in the same way as for gyro data in stabilization module.
const float fakeDt = 0.0025;
if(attitudeSettings.AccelTau < 0.0001)
accel_alpha_setting = 0; // not trusting this to resolve to 0
else
accel_alpha_setting = expf(-fakeDt / attitudeSettings.AccelTau);
if(attitudeSettings.AccelTau < 0.0001) {
accel_alpha = 0; // not trusting this to resolve to 0
accel_filter_enabled = false;
} else {
accel_alpha = expf(-fakeDt / attitudeSettings.AccelTau);
accel_filter_enabled = true;
}
accel_alpha = accel_alpha_setting;
zero_during_arming = attitudeSettings.ZeroDuringArming == ATTITUDESETTINGS_ZERODURINGARMING_TRUE;
bias_correct_gyro = attitudeSettings.BiasCorrectGyro == ATTITUDESETTINGS_BIASCORRECTGYRO_TRUE;