source: flair-src/trunk/lib/FlairFilter/src/AhrsComplementaryFilter.cpp@ 148

Last change on this file since 148 was 24, checked in by Sanahuja Guillaume, 6 years ago

complementary filter

File size: 4.9 KB
Line 
1// %flair:license{
2// This file is part of the Flair framework distributed under the
3// CECILL-C License, Version 1.0.
4// %flair:license}
5
6// created: 2014/04/28
7// filename: AhrsComplementaryFilter.cpp
8//
9// authors: Augustin Manecy (RT-MaG Toolbox author, augustin.manecy@gmail.com)
10// API changes by Guillaume Sanahuja to fit the Flair framework
11//
12// version: $Id: $
13//
14// purpose: Class defining an Ahrs complementary filter
15//
16//
17/*********************************************************************/
18
19#include "AhrsComplementaryFilter.h"
20#include <Imu.h>
21#include <DoubleSpinBox.h>
22#include <GridLayout.h>
23#include <ImuData.h>
24#include <AhrsData.h>
25#include <math.h>
26
27#define G 9.81
28
29using std::string;
30using namespace flair::core;
31using namespace flair::gui;
32using namespace flair::sensor;
33
34namespace flair { namespace filter {
35
36AhrsComplementaryFilter::AhrsComplementaryFilter(const Imu* parent,string name): isInit(false), Ahrs(parent,name) {
37
38 QHat.q0=1;
39 QHat.q1=0;
40 QHat.q2=0;
41 QHat.q3=0;
42 BHat.x=0;
43 BHat.y=0;
44 BHat.z=0;
45
46 ka[0]=new DoubleSpinBox(parent->GetLayout()->NewRow(),"ka[0]:",0.,10,0.1,2,0.5);
47 ka[1]=new DoubleSpinBox(parent->GetLayout()->LastRowLastCol(),"ka[1]:",0.,10,0.1,2,0.5);
48 ka[2]=new DoubleSpinBox(parent->GetLayout()->LastRowLastCol(),"ka[2]:",0.,10.,0.1,2,0.);
49
50 kb[0]=new DoubleSpinBox(parent->GetLayout()->NewRow(),"kb[0]:",0.,10,0.1,2,0.01);
51 kb[1]=new DoubleSpinBox(parent->GetLayout()->LastRowLastCol(),"kb[1]:",0.,10,0.1,2,0.01);
52 kb[2]=new DoubleSpinBox(parent->GetLayout()->LastRowLastCol(),"kb[2]:",0.,10,0.1,2,0.01);
53
54}
55
56AhrsComplementaryFilter::~AhrsComplementaryFilter() {
57
58}
59
60void AhrsComplementaryFilter::UpdateFrom(const io_data *data) {
61 ImuData *input=(ImuData*)data;
62 float delta_t;
63 AhrsData* ahrsData;
64 GetDatas(&ahrsData);
65 Vector3D rawAcc,rawMag,rawGyr;
66 input->GetRawAccMagAndGyr(rawAcc,rawMag,rawGyr);
67
68 delta_t=(float)(data->DataTime()-previous_time)/1000000000.;
69 previous_time=data->DataTime();
70
71 Vector3D aBar,aHat,aTilde;
72 Vector3D mBar,mHat,mTilde;
73 Vector3D alpha,dBHat,omegaHat;
74 Quaternion dQHat;
75
76 //float ka[3]={0.5,0.5,0};
77 //float kb[3]={0.01,0.01,0.01};
78 float k_m[3]= {0,0,0};
79
80 if(isInit==true) {
81 // CORRECTION FORM ACCELEROMETER
82 aBar = rawAcc;
83
84 // estimation of IMU vector using QHat (estimated quaternion): aHat = Inv(QHat) * g
85 /*
86 Inv(QHat) = [q0 -q1 -q2 -q3]'
87 Inv(QHat)*g = [1-2(q2^2+q3^2) 2(q1q2+q0q3) 2(q1q3-q0q2)] [0]
88 [ 2(q1q2-q0q3) 1-2(q1^2+q3^2)) 2(q2q3+q0q1)] * [0]
89 [ 2(q1q3+q0q2) 2(q2q3-q0q1) 1-2(q1^2+q2^2)] [g]
90 */
91 aHat.x = -2*G*(QHat.q1*QHat.q3 - QHat.q0*QHat.q2);
92 aHat.y = -2*G*(QHat.q2*QHat.q3 + QHat.q0*QHat.q1);
93 aHat.z = -G*(1-2.0*(QHat.q1*QHat.q1 + QHat.q2*QHat.q2));
94
95 // cross(aHat, aBar)
96 aTilde=CrossProduct(aHat, aBar);
97
98 // CORRECTION FROM FICTIOUS MAGNETOMETER (to avoid drift of yaw)
99 // estimation of IMU vector using QHat (estimated quaternion): mHat = Inv(QHat) * m_ref = Inv(QHat) * [1.0, 0.0, 0.0]'
100 /*
101 Inv(QHat) = [q0 -q1 -q2 -q3]'
102 Inv(QHat)*g = [1-2(q2^2+q3^2) 2(q1q2+q0q3) 2(q1q3-q0q2)] [1]
103 [ 2(q1q2-q0q3) 1-2(q1^2+q3^2)) 2(q2q3+q0q1)] * [0]
104 [ 2(q1q3+q0q2) 2(q2q3-q0q1) 1-2(q1^2+q2^2)] [0]
105 */
106 mBar.x=1;
107 mBar.y=0;
108 mBar.z=0;
109
110 mHat.x = (1-2.0*(QHat.q2*QHat.q2 + QHat.q3*QHat.q3));
111 mHat.y = 2.0*(QHat.q1*QHat.q2 - QHat.q0*QHat.q3);
112 mHat.z = 2.0*(QHat.q1*QHat.q3 + QHat.q0*QHat.q2);
113
114 // compute the error between mHat and mTilde
115 mTilde=CrossProduct(mHat, mBar);
116
117 // Compute the debiased rotation speed
118 omegaHat = rawGyr - BHat;
119
120 // calculate the correction to apply to the quaternion
121 alpha.x = (ka[0]->Value()*aTilde.x)/(G*G) + (k_m[0]*mTilde.x);
122 alpha.y = (ka[1]->Value()*aTilde.y)/(G*G) + (k_m[1]*mTilde.y);
123 alpha.z = (ka[2]->Value()*aTilde.z)/(G*G) + (k_m[2]*mTilde.z);
124
125 // Bias derivative
126 dBHat.x = kb[0]->Value() * alpha.x;
127 dBHat.y = kb[1]->Value() * alpha.y;
128 dBHat.z = kb[2]->Value() * alpha.z;
129
130 // Bias integration
131 BHat = BHat+dBHat*delta_t;
132
133 // Quaternion derivative: dQHat = 0.5*(QHat*Q_corr)
134 // Q_corr: Corrected pure rotation quaternion for integration
135 dQHat=QHat.GetDerivative(omegaHat - alpha);
136
137 // Quaternion integration
138 QHat = QHat +dQHat*delta_t; // delta_t: sampling period [s]
139
140 QHat.Normalize();
141
142 ahrsData->SetQuaternionAndAngularRates(QHat,rawGyr - BHat);
143
144 } else {
145 isInit=true;
146 }
147
148 ahrsData->SetDataTime(data->DataTime());
149 ProcessUpdate(ahrsData);
150}
151
152} // end namespace filter
153} // end namespace flair
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