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new simple complementary filter to calculate current altitude and vertical speed

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This commit is contained in:
Corvus Corax 2013-06-28 17:22:16 +02:00
parent 0c43346292
commit b9038e5ed6
3 changed files with 200 additions and 5 deletions
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186
flight/modules/StateEstimation/filteraltitude.c Normal file
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@ -0,0 +1,186 @@
/**
******************************************************************************
* @addtogroup OpenPilotModules OpenPilot Modules
* @{
* @addtogroup State Estimation
* @brief Acquires sensor data and computes state estimate
* @{
*
* @file filteraltitude.c
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2013.
* @brief Barometric altitude filter, calculates vertical speed and true
* altitude based on Barometric altitude and accelerometers
*
* @see The GNU Public License (GPL) Version 3
*
******************************************************************************/
/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "inc/stateestimation.h"
#include <attitudestate.h>
#include <CoordinateConversions.h>
// Private constants
#define STACK_REQUIRED 128
#define BARO_SENSOR_KP 0.05f
#define ACCEL_DRIFT_KP 0.001f
#define DT_ALPHA 1e-3f
// Private types
struct data {
float state[3]; // state = altitude,velocity,accel_offset
float pos[3]; // position updates from other filters
float vel[3]; // position updates from other filters
float dTA;
int32_t lastTime;
float baroLast;
int32_t baroLastTime;
bool first_run;
};
// Private variables
// Private functions
static int32_t init(stateFilter *self);
static int32_t filter(stateFilter *self, stateEstimation *state);
int32_t filterAltitudeInitialize(stateFilter *handle)
{
handle->init = &init;
handle->filter = &filter;
handle->localdata = pvPortMalloc(sizeof(struct data));
AttitudeStateInitialize();
return STACK_REQUIRED;
}
static int32_t init(stateFilter *self)
{
struct data *this = (struct data *)self->localdata;
this->state[0] = 0.0f;
this->state[1] = 0.0f;
this->state[2] = 0.0f;
this->pos[0] = 0.0f;
this->pos[1] = 0.0f;
this->pos[2] = 0.0f;
this->vel[0] = 0.0f;
this->vel[1] = 0.0f;
this->vel[2] = 0.0f;
this->dTA = -1;
this->first_run = 1;
return 0;
}
static int32_t filter(stateFilter *self, stateEstimation *state)
{
struct data *this = (struct data *)self->localdata;
if (this->first_run) {
// Initialize to current altitude reading at initial location
if (IS_SET(state->updated, SENSORUPDATES_accel)) {
this->lastTime = PIOS_DELAY_GetRaw();
}
if (IS_SET(state->updated, SENSORUPDATES_baro)) {
this->first_run = 0;
this->baroLastTime = PIOS_DELAY_GetRaw();
this->state[0] = state->baro[0];
this->baroLast = state->baro[0];
}
} else {
// save existing position and velocity updates so GPS will still work
if (IS_SET(state->updated, SENSORUPDATES_pos)) {
this->pos[0] = state->pos[0];
this->pos[1] = state->pos[1];
this->pos[2] = state->pos[2];
state->pos[2] = -this->state[0];
}
if (IS_SET(state->updated, SENSORUPDATES_vel)) {
this->vel[0] = state->vel[0];
this->vel[1] = state->vel[1];
this->vel[2] = state->vel[2];
state->vel[2] = -this->state[1];
}
if(IS_SET(state->updated, SENSORUPDATES_accel)) {
// rotate accels into global coordinate frame
AttitudeStateData att;
AttitudeStateGet(&att);
float Rbe[3][3];
Quaternion2R(&att.q1, Rbe);
float current = -(Rbe[0][2] * state->accel[0] + Rbe[1][2] * state->accel[1] + Rbe[2][2] * state->accel[2] + 9.81f);
// correct accel offset (low pass zeroing)
this->state[2] = (1.0f - ACCEL_DRIFT_KP) * this->state[2] + ACCEL_DRIFT_KP * current;
// correct velocity and position state (integration)
// low pass for average dT, compensate timing jitter from scheduler
float dT = PIOS_DELAY_DiffuS(this->lastTime) / 1.0e6f;
if (this->dTA<0) {
this->dTA = dT;
} else {
this->dTA = this->dTA * (1.0f - DT_ALPHA) + dT * DT_ALPHA;
}
this->state[1] += (current - this->state[1]) * this->dTA;
this->state[0] += this->state[1] * this->dTA;
state->pos[0] = this->pos[0];
state->pos[1] = this->pos[2];
state->pos[2] = -this->state[0];
state->updated |= SENSORUPDATES_pos;
state->vel[0] = this->vel[0];
state->vel[1] = this->vel[2];
state->vel[2] = -this->state[0];
state->updated |= SENSORUPDATES_vel;
}
if (IS_SET(state->updated, SENSORUPDATES_baro)) {
// correct the altitude state (simple low pass)
this->state[0] = (1.0f - BARO_SENSOR_KP) * this->state[0] + BARO_SENSOR_KP * state->baro[0];
// correct the velocity state (low pass differentiation)
float dT = PIOS_DELAY_DiffuS(this->baroLastTime) / 1.0e6f;
if (dT<0.001f) dT = 0.001f;
this->state[1] = (1.0f - BARO_SENSOR_KP) * this->state[1] + BARO_SENSOR_KP * (state->baro[0] - this->baroLast) / dT;
this->baroLast = state->baro[0];
state->pos[0] = this->pos[0];
state->pos[1] = this->pos[2];
state->pos[2] = -this->state[0];
state->updated |= SENSORUPDATES_pos;
state->vel[0] = this->vel[0];
state->vel[1] = this->vel[2];
state->vel[2] = -this->state[0];
state->updated |= SENSORUPDATES_vel;
}
}
return 0;
}
/**
* @}
* @}
*/

1
flight/modules/StateEstimation/inc/stateestimation.h
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@ -64,6 +64,7 @@ typedef struct stateFilterStruct {
int32_t filterMagInitialize(stateFilter *handle);
int32_t filterBaroInitialize(stateFilter *handle);
int32_t filterAltitudeInitialize(stateFilter *handle);
int32_t filterAirInitialize(stateFilter *handle);
int32_t filterStationaryInitialize(stateFilter *handle);
int32_t filterCFInitialize(stateFilter *handle);

18
flight/modules/StateEstimation/stateestimation.c
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@ -123,6 +123,7 @@ static filterPipeline *filterChain = NULL;
// different filters available to state estimation
static stateFilter magFilter;
static stateFilter baroFilter;
static stateFilter altitudeFilter;
static stateFilter airFilter;
static stateFilter stationaryFilter;
static stateFilter cfFilter;
@ -138,9 +139,12 @@ static filterPipeline *cfQueue = &(filterPipeline) {
.next = &(filterPipeline) {
.filter = &baroFilter,
.next = &(filterPipeline) {
.filter = &cfFilter,
.next = NULL,
},
.filter = &altitudeFilter,
.next = &(filterPipeline) {
.filter = &cfFilter,
.next = NULL,
}
}
}
}
};
@ -151,8 +155,11 @@ static const filterPipeline *cfmQueue = &(filterPipeline) {
.next = &(filterPipeline) {
.filter = &baroFilter,
.next = &(filterPipeline) {
.filter = &cfmFilter,
.next = NULL,
.filter = &altitudeFilter,
.next = &(filterPipeline) {
.filter = &cfmFilter,
.next = NULL,
}
}
}
}
@ -237,6 +244,7 @@ int32_t StateEstimationInitialize(void)
// Initialize Filters
stack_required = maxint32_t(stack_required, filterMagInitialize(&magFilter));
stack_required = maxint32_t(stack_required, filterBaroInitialize(&baroFilter));
stack_required = maxint32_t(stack_required, filterAltitudeInitialize(&altitudeFilter));
stack_required = maxint32_t(stack_required, filterAirInitialize(&airFilter));
stack_required = maxint32_t(stack_required, filterStationaryInitialize(&stationaryFilter));
stack_required = maxint32_t(stack_required, filterCFInitialize(&cfFilter));