source: flair-src/trunk/lib/FlairFilter/src/AhrsComplementaryFilter.cpp@ 157

Last change on this file since 157 was 157, checked in by Sanahuja Guillaume, 6 years ago

iadded isready to iodevice:
avoid problem of imu not ready in ardrone2

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 SetIsReady(true);
55}
56
57AhrsComplementaryFilter::~AhrsComplementaryFilter() {
58
59}
60
61void AhrsComplementaryFilter::UpdateFrom(const io_data *data) {
62 ImuData *input=(ImuData*)data;
63 float delta_t;
64 AhrsData* ahrsData;
65 GetDatas(&ahrsData);
66 Vector3D rawAcc,rawMag,rawGyr;
67 input->GetRawAccMagAndGyr(rawAcc,rawMag,rawGyr);
68
69 delta_t=(float)(data->DataTime()-previous_time)/1000000000.;
70 previous_time=data->DataTime();
71
72 Vector3D aBar,aHat,aTilde;
73 Vector3D mBar,mHat,mTilde;
74 Vector3D alpha,dBHat,omegaHat;
75 Quaternion dQHat;
76
77 //float ka[3]={0.5,0.5,0};
78 //float kb[3]={0.01,0.01,0.01};
79 float k_m[3]= {0,0,0};
80
81 if(isInit==true) {
82 // CORRECTION FORM ACCELEROMETER
83 aBar = rawAcc;
84
85 // estimation of IMU vector using QHat (estimated quaternion): aHat = Inv(QHat) * g
86 /*
87 Inv(QHat) = [q0 -q1 -q2 -q3]'
88 Inv(QHat)*g = [1-2(q2^2+q3^2) 2(q1q2+q0q3) 2(q1q3-q0q2)] [0]
89 [ 2(q1q2-q0q3) 1-2(q1^2+q3^2)) 2(q2q3+q0q1)] * [0]
90 [ 2(q1q3+q0q2) 2(q2q3-q0q1) 1-2(q1^2+q2^2)] [g]
91 */
92 aHat.x = -2*G*(QHat.q1*QHat.q3 - QHat.q0*QHat.q2);
93 aHat.y = -2*G*(QHat.q2*QHat.q3 + QHat.q0*QHat.q1);
94 aHat.z = -G*(1-2.0*(QHat.q1*QHat.q1 + QHat.q2*QHat.q2));
95
96 // cross(aHat, aBar)
97 aTilde=CrossProduct(aHat, aBar);
98
99 // CORRECTION FROM FICTIOUS MAGNETOMETER (to avoid drift of yaw)
100 // estimation of IMU vector using QHat (estimated quaternion): mHat = Inv(QHat) * m_ref = Inv(QHat) * [1.0, 0.0, 0.0]'
101 /*
102 Inv(QHat) = [q0 -q1 -q2 -q3]'
103 Inv(QHat)*g = [1-2(q2^2+q3^2) 2(q1q2+q0q3) 2(q1q3-q0q2)] [1]
104 [ 2(q1q2-q0q3) 1-2(q1^2+q3^2)) 2(q2q3+q0q1)] * [0]
105 [ 2(q1q3+q0q2) 2(q2q3-q0q1) 1-2(q1^2+q2^2)] [0]
106 */
107 mBar.x=1;
108 mBar.y=0;
109 mBar.z=0;
110
111 mHat.x = (1-2.0*(QHat.q2*QHat.q2 + QHat.q3*QHat.q3));
112 mHat.y = 2.0*(QHat.q1*QHat.q2 - QHat.q0*QHat.q3);
113 mHat.z = 2.0*(QHat.q1*QHat.q3 + QHat.q0*QHat.q2);
114
115 // compute the error between mHat and mTilde
116 mTilde=CrossProduct(mHat, mBar);
117
118 // Compute the debiased rotation speed
119 omegaHat = rawGyr - BHat;
120
121 // calculate the correction to apply to the quaternion
122 alpha.x = (ka[0]->Value()*aTilde.x)/(G*G) + (k_m[0]*mTilde.x);
123 alpha.y = (ka[1]->Value()*aTilde.y)/(G*G) + (k_m[1]*mTilde.y);
124 alpha.z = (ka[2]->Value()*aTilde.z)/(G*G) + (k_m[2]*mTilde.z);
125
126 // Bias derivative
127 dBHat.x = kb[0]->Value() * alpha.x;
128 dBHat.y = kb[1]->Value() * alpha.y;
129 dBHat.z = kb[2]->Value() * alpha.z;
130
131 // Bias integration
132 BHat = BHat+dBHat*delta_t;
133
134 // Quaternion derivative: dQHat = 0.5*(QHat*Q_corr)
135 // Q_corr: Corrected pure rotation quaternion for integration
136 dQHat=QHat.GetDerivative(omegaHat - alpha);
137
138 // Quaternion integration
139 QHat = QHat +dQHat*delta_t; // delta_t: sampling period [s]
140
141 QHat.Normalize();
142
143 ahrsData->SetQuaternionAndAngularRates(QHat,rawGyr - BHat);
144
145 } else {
146 isInit=true;
147 }
148
149 ahrsData->SetDataTime(data->DataTime());
150 ProcessUpdate(ahrsData);
151}
152
153} // end namespace filter
154} // end namespace flair
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