source: flair-src/trunk/lib/FlairFilter/src/AhrsComplementaryFilter.cpp@ 197

// %flair:license{

// This file is part of the Flair framework distributed under the

// CECILL-C License, Version 1.0.

// %flair:license}



//  created:    2014/04/28

//  filename:   AhrsComplementaryFilter.cpp

//

//  authors:    Augustin Manecy (RT-MaG Toolbox author, augustin.manecy@gmail.com)

//              API changes by Guillaume Sanahuja to fit the Flair framework

//

//  version:    $Id: $

//

//  purpose:    Class defining an Ahrs complementary filter

//

//

/*********************************************************************/



#include "AhrsComplementaryFilter.h"

#include <Imu.h>

#include <DoubleSpinBox.h>

#include <GridLayout.h>

#include <ImuData.h>

#include <AhrsData.h>

#include <math.h>



#define G 9.81



using std::string;

using namespace flair::core;

using namespace flair::gui;

using namespace flair::sensor;



namespace flair { namespace filter {



AhrsComplementaryFilter::AhrsComplementaryFilter(const Imu* parent,string name): isInit(false), Ahrs(parent,name) {



    QHat.q0=1;

    QHat.q1=0;

    QHat.q2=0;

    QHat.q3=0;

    BHat.x=0;

    BHat.y=0;

    BHat.z=0;



    ka[0]=new DoubleSpinBox(parent->GetLayout()->NewRow(),"ka[0]:",0.,10,0.1,2,0.5);

    ka[1]=new DoubleSpinBox(parent->GetLayout()->LastRowLastCol(),"ka[1]:",0.,10,0.1,2,0.5);

    ka[2]=new DoubleSpinBox(parent->GetLayout()->LastRowLastCol(),"ka[2]:",0.,10.,0.1,2,0.);



    kb[0]=new DoubleSpinBox(parent->GetLayout()->NewRow(),"kb[0]:",0.,10,0.1,2,0.01);

    kb[1]=new DoubleSpinBox(parent->GetLayout()->LastRowLastCol(),"kb[1]:",0.,10,0.1,2,0.01);

    kb[2]=new DoubleSpinBox(parent->GetLayout()->LastRowLastCol(),"kb[2]:",0.,10,0.1,2,0.01);

    

    km[0]=new DoubleSpinBox(parent->GetLayout()->NewRow(),"km[0]:",0.,10,0.1,2,0.01);

    km[1]=new DoubleSpinBox(parent->GetLayout()->LastRowLastCol(),"km[1]:",0.,10,0.1,2,0.01);

    km[2]=new DoubleSpinBox(parent->GetLayout()->LastRowLastCol(),"km[2]:",0.,10,0.1,2,0.01);

  

  SetIsReady(true);

}



AhrsComplementaryFilter::~AhrsComplementaryFilter() {



}



void AhrsComplementaryFilter::UpdateFrom(const io_data *data) {

    ImuData *input=(ImuData*)data;

    float delta_t;

    AhrsData* ahrsData;

    GetDatas(&ahrsData);

    Vector3Df rawAcc,rawMag,rawGyr;

    input->GetRawAccMagAndGyr(rawAcc,rawMag,rawGyr);



    delta_t=(float)(data->DataTime()-previous_time)/1000000000.;

    previous_time=data->DataTime();



    Vector3Df aBar,aHat,aTilde;

    Vector3Df mBar,mHat,mTilde;

    Vector3Df alpha,dBHat,omegaHat,magRef;

    Quaternion dQHat;



    //float ka[3]={0.5,0.5,0};

    //float kb[3]={0.01,0.01,0.01};

    //float k_m[3]= {0,0,0};

magRef.x=20.8296;

magRef.y=.2095;

magRef.z=43.3333;



    if(isInit==true) {

        // CORRECTION FROM ACCELEROMETER

        aBar = rawAcc;



        // estimation of IMU vector using QHat (estimated quaternion): aHat = Inv(QHat) * g

        /*

          Inv(QHat) = [q0 -q1 -q2 -q3]'

          Inv(QHat)*g = [1-2(q2^2+q3^2)     2(q1q2+q0q3)     2(q1q3-q0q2)]     [0]

                         [  2(q1q2-q0q3)   1-2(q1^2+q3^2))    2(q2q3+q0q1)]  *  [0]

                         [  2(q1q3+q0q2)     2(q2q3-q0q1)   1-2(q1^2+q2^2)]     [g]

        */

        aHat.x = -2*G*(QHat.q1*QHat.q3 - QHat.q0*QHat.q2);

        aHat.y = -2*G*(QHat.q2*QHat.q3 + QHat.q0*QHat.q1);

        aHat.z = -G*(1-2.0*(QHat.q1*QHat.q1 + QHat.q2*QHat.q2));



        // cross(aHat, aBar)

        aTilde=CrossProduct(aHat, aBar);



        

        // CORRECTION FROM MAGNETOMETER

        // estimation of IMU vector using QHat (estimated quaternion): mHat = Inv(QHat) * m_ref = Inv(QHat) * magRef

        /*

          Inv(QHat) = [q0 -q1 -q2 -q3]'

          Inv(QHat)*g = [1-2(q2^2+q3^2)     2(q1q2+q0q3)     2(q1q3-q0q2)]     [magRef.x]

                         [  2(q1q2-q0q3)   1-2(q1^2+q3^2))    2(q2q3+q0q1)]  *  [magRef.x]

                         [  2(q1q3+q0q2)     2(q2q3-q0q1)   1-2(q1^2+q2^2)]     [magRef.x]

        */

        mBar=rawMag;

        

        mHat.x = (1-2.0*(QHat.q2*QHat.q2 + QHat.q3*QHat.q3))*magRef.x+2.0*(QHat.q1*QHat.q2+QHat.q0*QHat.q3)*magRef.y+2.0*(QHat.q1*QHat.q3-QHat.q0*QHat.q2)*magRef.z;

        mHat.y = 2.0*(QHat.q1*QHat.q2 - QHat.q0*QHat.q3)*magRef.x+(1-2.0*(QHat.q1*QHat.q1 + QHat.q3*QHat.q3))*magRef.y+2.0*(QHat.q2*QHat.q3 + QHat.q0*QHat.q1)*magRef.z;

        mHat.z = 2.0*(QHat.q1*QHat.q3+QHat.q0*QHat.q2)*magRef.x+2.0*(QHat.q2*QHat.q3 - QHat.q0*QHat.q1)*magRef.y+(1-2.0*(QHat.q1*QHat.q1 + QHat.q2*QHat.q2))*magRef.z;

       

        

        // compute the error between mHat and mTilde

        mTilde=CrossProduct(mHat, mBar);



        // Compute the debiased rotation speed

        omegaHat = rawGyr - BHat;



        // calculate the correction to apply to the quaternion

        alpha.x = (ka[0]->Value()*aTilde.x)/(G*G) + (km[0]->Value()*mTilde.x)/(magRef.GetNorm()*magRef.GetNorm());

        alpha.y = (ka[1]->Value()*aTilde.y)/(G*G) + (km[1]->Value()*mTilde.y)/(magRef.GetNorm()*magRef.GetNorm());

        alpha.z = (ka[2]->Value()*aTilde.z)/(G*G) + (km[2]->Value()*mTilde.z)/(magRef.GetNorm()*magRef.GetNorm());



        // Bias derivative

        dBHat.x = kb[0]->Value() * alpha.x;

        dBHat.y = kb[1]->Value() * alpha.y;

        dBHat.z = kb[2]->Value() * alpha.z;



        // Bias integration

        BHat = BHat+dBHat*delta_t;



        // Quaternion derivative: dQHat = 0.5*(QHat*Q_corr)

        // Q_corr: Corrected pure rotation quaternion for integration

        dQHat=QHat.GetDerivative(omegaHat - alpha);



        // Quaternion integration

        QHat = QHat +dQHat*delta_t;     // delta_t: sampling period [s]



        QHat.Normalize();



        ahrsData->SetQuaternionAndAngularRates(QHat,rawGyr - BHat);



    } else {

        isInit=true;

    }



    ahrsData->SetDataTime(data->DataTime());

    ProcessUpdate(ahrsData);

}



} // end namespace filter

} // end namespace flair