Akifumi Takahashi / MadgwickFilter

Madgewick Filter to get attitude from IMU or MARG. Confirmed IMU ver works well.

Dependencies:   Quaternion

Dependents:   NineIMUAttitude_MadgwickFilter

MadgwickFilter.hpp@8:72c013425ecc, 2020-08-21 (annotated)

Committer:
aktk
Date:
Fri Aug 21 03:13:08 2020 +0000
Revision:
8:72c013425ecc
Parent:
7:c20656d96585 
Forked and modified some parts

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Gaku0606 0:c160cac4c370 1 #ifndef _MADGWICK_FILTER_HPP_
Gaku0606 0:c160cac4c370 2 #define _MADGWICK_FILTER_HPP_
Gaku0606 0:c160cac4c370 3
Gaku0606 0:c160cac4c370 4 #include "mbed.h"
Gaku0606 0:c160cac4c370 5 #include "Quaternion.hpp"
Gaku0606 0:c160cac4c370 6
Gaku0606 0:c160cac4c370 7 #define BETA_DEF 0.1
Gaku0606 0:c160cac4c370 8
aktk 8:72c013425ecc 9
Gaku0606 0:c160cac4c370 10 /**
Gaku0606 2:e1de76e257f6 11 * @bref Madgwick Filterを用いて，角速度・加速度・地磁気データを統合し，姿勢を推定するライブラリです．
Gaku0606 2:e1de76e257f6 12 * @note Quaternion.hppを利用されることをお勧めいたします．
Gaku0606 0:c160cac4c370 13 */
aktk 8:72c013425ecc 14 class MadgwickFilter
aktk 8:72c013425ecc 15 {
aktk 8:72c013425ecc 16
Gaku0606 0:c160cac4c370 17 public:
Gaku0606 0:c160cac4c370 18 /**
Gaku0606 2:e1de76e257f6 19 @bref マドグウィックフィルター(マッジュウィックフィルター)クラスのコンストラクタ
Gaku0606 0:c160cac4c370 20 @param B double型, この値を大きくすると重力の影響を大きく取るようになります．
Gaku0606 0:c160cac4c370 21 @note 引数無しの場合，B = 0.1fが代入されます．
Gaku0606 0:c160cac4c370 22 */
aktk 8:72c013425ecc 23 MadgwickFilter(float B = BETA_DEF, float dT_sec = 0.05f);
aktk 8:72c013425ecc 24
Gaku0606 0:c160cac4c370 25 public:
Gaku0606 0:c160cac4c370 26 /**
Gaku0606 0:c160cac4c370 27 @bref MadgwickFilterによって角速度・加速度・地磁気データを統合し，姿勢計算します．
Gaku0606 0:c160cac4c370 28 @param gx,gy,gz 角速度データ，[rad]に変換してから入れてください．
Gaku0606 0:c160cac4c370 29 @param ax,ay,az 加速度データ, 特に規格化は必要ありません
Gaku0606 0:c160cac4c370 30 @param mx,my,mz 地磁気データ, キャリブレーションを確実に行って下さい．
Gaku0606 0:c160cac4c370 31 @note 角速度は[rad]にしてください．この関数は出来るだけ高速に呼び出し続けた方が良いと思います．
Gaku0606 0:c160cac4c370 32 @note 外部でローパスフィルタなどをかけることをお勧めします．
Gaku0606 0:c160cac4c370 33 */
Gaku0606 6:eff5ebc4ea13 34 void MadgwickAHRSupdate(float gx, float gy, float gz, float ax, float ay, float az, float mx, float my, float mz);
aktk 8:72c013425ecc 35
aktk 8:72c013425ecc 36 /**
aktk 8:72c013425ecc 37 @bref MadgwickFilterによって角速度・加速度・地磁気データを統合し，姿勢計算します．
aktk 8:72c013425ecc 38 @param gyro 角速度データ，[rad]に変換してから入れてください．
aktk 8:72c013425ecc 39 @param acc 加速度データ, 特に規格化は必要ありません
aktk 8:72c013425ecc 40 @param mag 地磁気データ, キャリブレーションを確実に行って下さい．
aktk 8:72c013425ecc 41 @note 角速度は[rad]にしてください．この関数は出来るだけ高速に呼び出し続けた方が良いと思います．
aktk 8:72c013425ecc 42 @note 外部でローパスフィルタなどをかけることをお勧めします．
Gaku0606 7:c20656d96585 43 */
Gaku0606 7:c20656d96585 44 void MadgwickAHRSupdate(float *gyro, float *acc, float *mag);
aktk 8:72c013425ecc 45
Gaku0606 0:c160cac4c370 46 /**
Gaku0606 0:c160cac4c370 47 @bref MadgwickFilterを角速度と加速度のみで動かし，姿勢計算を更新します．
Gaku0606 0:c160cac4c370 48 @param gx,gy,gz 角速度データ，[rad]に変換してから入れてください．
Gaku0606 0:c160cac4c370 49 @param ax,ay,az 加速度データ, 特に規格化は必要ありません
Gaku0606 0:c160cac4c370 50 @note 通常の関数でも，地磁気成分を0.0にすればこの関数が呼ばれます．
Gaku0606 0:c160cac4c370 51 */
Gaku0606 6:eff5ebc4ea13 52 void MadgwickAHRSupdateIMU(float gx, float gy, float gz, float ax, float ay, float az);
aktk 8:72c013425ecc 53
Gaku0606 0:c160cac4c370 54 /**
Gaku0606 0:c160cac4c370 55 @bref 姿勢を四元数で取得します．
Gaku0606 0:c160cac4c370 56 @param Q クォータニオンクラスのインスタンスアドレス, w・i・j・kを更新します．
Gaku0606 0:c160cac4c370 57 @note unityに入れる際は軸方向を修正してください．
Gaku0606 0:c160cac4c370 58 */
Gaku0606 0:c160cac4c370 59 void getAttitude(Quaternion *Q);
aktk 8:72c013425ecc 60
Gaku0606 0:c160cac4c370 61 /**
Gaku0606 0:c160cac4c370 62 @bref 姿勢を四元数で取得します．
Gaku0606 0:c160cac4c370 63 @param _q0 実部w, double型, アドレス
Gaku0606 0:c160cac4c370 64 @param _q1 虚部i, double型, アドレス
Gaku0606 0:c160cac4c370 65 @param _q2 虚部j, double型, アドレス
Gaku0606 0:c160cac4c370 66 @param _q3 虚部k, double型, アドレス
Gaku0606 0:c160cac4c370 67 @note unityに入れる際は軸方向を修正してください．
Gaku0606 0:c160cac4c370 68 */
Gaku0606 6:eff5ebc4ea13 69 void getAttitude(float *_q0, float *_q1, float *_q2, float *_q3);
aktk 8:72c013425ecc 70
Gaku0606 0:c160cac4c370 71 /**
Gaku0606 0:c160cac4c370 72 @bref オイラー角で姿勢を取得します．
Gaku0606 0:c160cac4c370 73 @param val ロール，ピッチ，ヨーの順に配列に格納します．３つ以上の要素の配列を入れてください．
Gaku0606 0:c160cac4c370 74 @note 値は[rad]です．[degree]に変換が必要な場合は別途計算して下さい．
Gaku0606 0:c160cac4c370 75 */
Gaku0606 6:eff5ebc4ea13 76 void getEulerAngle(float *val);
Gaku0606 0:c160cac4c370 77 public:
Gaku0606 0:c160cac4c370 78 Timer madgwickTimer;
Gaku0606 0:c160cac4c370 79 Quaternion q;
Gaku0606 6:eff5ebc4ea13 80 float q0,q1,q2,q3;
aktk 8:72c013425ecc 81 float beta;
aktk 8:72c013425ecc 82 float zeta;
aktk 8:72c013425ecc 83 float deltaT_sec;
aktk 8:72c013425ecc 84 static int counter_numofojbect;
aktk 8:72c013425ecc 85 int ID;
aktk 8:72c013425ecc 86
aktk 8:72c013425ecc 87 // Var for UpadateIMU
aktk 8:72c013425ecc 88 private:
aktk 8:72c013425ecc 89 float deltaT;
aktk 8:72c013425ecc 90 unsigned int newTime, oldTime;
aktk 8:72c013425ecc 91 float recipNorm;
aktk 8:72c013425ecc 92 float s0, s1, s2, s3;
aktk 8:72c013425ecc 93 float qDot1, qDot2, qDot3, qDot4;
aktk 8:72c013425ecc 94 float _2q0, _2q1, _2q2, _2q3, _4q0, _4q1, _4q2,_8q1, _8q2, q0q0, q1q1, q2q2, q3q3;
aktk 8:72c013425ecc 95 float acc_norm;
Gaku0606 0:c160cac4c370 96 };
Gaku0606 0:c160cac4c370 97
aktk 8:72c013425ecc 98 int MadgwickFilter::counter_numofojbect = 0;
aktk 8:72c013425ecc 99
aktk 8:72c013425ecc 100 MadgwickFilter::MadgwickFilter(float B, float dT_sec)
aktk 8:72c013425ecc 101 {
aktk 8:72c013425ecc 102 ID = counter_numofojbect;
aktk 8:72c013425ecc 103 counter_numofojbect++;
Gaku0606 0:c160cac4c370 104 q.w = 1.0f;
Gaku0606 0:c160cac4c370 105 q.x = 0.0f;
Gaku0606 0:c160cac4c370 106 q.y = 0.0f;
Gaku0606 0:c160cac4c370 107 q.z = 0.0f;
Gaku0606 0:c160cac4c370 108 beta = B;
aktk 8:72c013425ecc 109 zeta = beta * 0.2 /5;
aktk 8:72c013425ecc 110 deltaT_sec = dT_sec;
Gaku0606 0:c160cac4c370 111 q0 = 1.0f;
Gaku0606 0:c160cac4c370 112 q1 = 0.0f;
Gaku0606 0:c160cac4c370 113 q2 = 0.0f;
aktk 8:72c013425ecc 114 q3 = 0.0f;
Gaku0606 0:c160cac4c370 115 madgwickTimer.start();
Gaku0606 0:c160cac4c370 116 }
Gaku0606 0:c160cac4c370 117
aktk 8:72c013425ecc 118 void MadgwickFilter::getAttitude(Quaternion *Q)
aktk 8:72c013425ecc 119 {
Gaku0606 0:c160cac4c370 120 *Q = q;
aktk 8:72c013425ecc 121 return;
Gaku0606 0:c160cac4c370 122 }
Gaku0606 0:c160cac4c370 123
Gaku0606 0:c160cac4c370 124
Gaku0606 0:c160cac4c370 125
aktk 8:72c013425ecc 126 void MadgwickFilter::getAttitude(float *_q0, float *_q1, float *_q2, float *_q3)
aktk 8:72c013425ecc 127 {
Gaku0606 0:c160cac4c370 128 *_q0 = q0;
Gaku0606 0:c160cac4c370 129 *_q1 = q1;
Gaku0606 0:c160cac4c370 130 *_q2 = q2;
Gaku0606 0:c160cac4c370 131 *_q3 = q3;
aktk 8:72c013425ecc 132 return;
Gaku0606 0:c160cac4c370 133 }
Gaku0606 0:c160cac4c370 134
Gaku0606 0:c160cac4c370 135
aktk 8:72c013425ecc 136 void MadgwickFilter::getEulerAngle(float *val)
aktk 8:72c013425ecc 137 {
Gaku0606 6:eff5ebc4ea13 138 float q0q0 = q0 * q0, q1q1q2q2 = q1 * q1 - q2 * q2, q3q3 = q3 * q3;
Gaku0606 0:c160cac4c370 139 val[0] = (atan2(2.0f * (q0 * q1 + q2 * q3), q0q0 - q1q1q2q2 + q3q3));
Gaku0606 0:c160cac4c370 140 val[1] = (-asin(2.0f * (q1 * q3 - q0 * q2)));
Gaku0606 0:c160cac4c370 141 val[2] = (atan2(2.0f * (q1 * q2 + q0 * q3), q0q0 + q1q1q2q2 - q3q3));
Gaku0606 0:c160cac4c370 142 }
Gaku0606 0:c160cac4c370 143 //---------------------------------------------------------------------------------------------------
Gaku0606 0:c160cac4c370 144 // AHRS algorithm update
Gaku0606 0:c160cac4c370 145
aktk 8:72c013425ecc 146 inline void MadgwickFilter::MadgwickAHRSupdate(float gx, float gy, float gz, float ax, float ay, float az, float mx, float my, float mz)
aktk 8:72c013425ecc 147 {
aktk 8:72c013425ecc 148
aktk 8:72c013425ecc 149 static float acc_norm;
aktk 8:72c013425ecc 150 static float deltaT = 0.0f;
aktk 8:72c013425ecc 151 static unsigned int newTime = 0, oldTime = 0;
aktk 8:72c013425ecc 152 static float recipNorm;
aktk 8:72c013425ecc 153 static float s0, s1, s2, s3;
aktk 8:72c013425ecc 154 static float qDot1, qDot2, qDot3, qDot4;
aktk 8:72c013425ecc 155 static float w_bx = 0, w_by = 0, w_bz = 0;
aktk 8:72c013425ecc 156 static float hx=0, hy=0, hz=0;
aktk 8:72c013425ecc 157 static float init_itr = 0;
aktk 8:72c013425ecc 158 //static float _2q0mx, _2q0my, _2q0mz, _2q1mx, bx = 0.0f, bz = 1.0f, _2bx, _2bz, _2q0, _2q1, _2q2, _2q3, _2q0q2, _2q2q3, q0q0, q0q1, q0q2, q0q3, q1q1, q1q2, q1q3, q2q2, q2q3, q3q3;
aktk 8:72c013425ecc 159 static float _2q0mx, _2q0my, _2q0mz, _2q1mx, bx = 0.0f, bz = 1.0f, _2bx, _2bz, _2q0, _2q1, _2q2, _2q3, _2q0q2, _2q2q3, q0q0, q0q1, q0q2, q0q3, q1q1, q1q2, q1q3, q2q2, q2q3, q3q3;
aktk 8:72c013425ecc 160
aktk 8:72c013425ecc 161 /*
aktk 8:72c013425ecc 162 // Use IMU algorithm if magnetometer measurement invalid (avoids NaN in magnetometer normalisation)
aktk 8:72c013425ecc 163 if((mx == 0.0f) && (my == 0.0f) && (mz == 0.0f)) {
aktk 8:72c013425ecc 164 MadgwickAHRSupdateIMU(gx, gy, gz, ax, ay, az);
aktk 8:72c013425ecc 165 return;
aktk 8:72c013425ecc 166 }
aktk 8:72c013425ecc 167 */
aktk 8:72c013425ecc 168
aktk 8:72c013425ecc 169 // Compute feedback only if accelerometer measurement valid (avoids NaN in accelerometer normalisation)
aktk 8:72c013425ecc 170 if(!((ax == 0.0f) && (ay == 0.0f) && (az == 0.0f))) {
aktk 8:72c013425ecc 171
aktk 8:72c013425ecc 172 // Normalise accelerometer measurement
aktk 8:72c013425ecc 173 acc_norm = sqrt(ax * ax + ay * ay + az * az);
aktk 8:72c013425ecc 174 recipNorm = 1.0f / acc_norm;
aktk 8:72c013425ecc 175 ax *= recipNorm;
aktk 8:72c013425ecc 176 ay *= recipNorm;
aktk 8:72c013425ecc 177 az *= recipNorm;
aktk 8:72c013425ecc 178
aktk 8:72c013425ecc 179 // Normalise magnetometer measurement
aktk 8:72c013425ecc 180 if((mx == 0.0f) && (my == 0.0f) && (mz == 0.0f)) {
aktk 8:72c013425ecc 181 recipNorm = 1.0f;
aktk 8:72c013425ecc 182 } else {
aktk 8:72c013425ecc 183 recipNorm = 1.0f / sqrt(mx * mx + my * my + mz * mz);
aktk 8:72c013425ecc 184 }
aktk 8:72c013425ecc 185 mx *= recipNorm;
aktk 8:72c013425ecc 186 my *= recipNorm;
aktk 8:72c013425ecc 187 mz *= recipNorm;
aktk 8:72c013425ecc 188
aktk 8:72c013425ecc 189 // Auxiliary variables to avoid repeated arithmetic
aktk 8:72c013425ecc 190 _2q0mx = 2.0f * q0 * mx;
aktk 8:72c013425ecc 191 _2q0my = 2.0f * q0 * my;
aktk 8:72c013425ecc 192 _2q0mz = 2.0f * q0 * mz;
aktk 8:72c013425ecc 193 _2q1mx = 2.0f * q1 * mx;
aktk 8:72c013425ecc 194 _2q0 = 2.0f * q0;
aktk 8:72c013425ecc 195 _2q1 = 2.0f * q1;
aktk 8:72c013425ecc 196 _2q2 = 2.0f * q2;
aktk 8:72c013425ecc 197 _2q3 = 2.0f * q3;
aktk 8:72c013425ecc 198 _2q0q2 = 2.0f * q0 * q2;
aktk 8:72c013425ecc 199 _2q2q3 = 2.0f * q2 * q3;
aktk 8:72c013425ecc 200 q0q0 = q0 * q0;
aktk 8:72c013425ecc 201 q0q1 = q0 * q1;
aktk 8:72c013425ecc 202 q0q2 = q0 * q2;
aktk 8:72c013425ecc 203 q0q3 = q0 * q3;
aktk 8:72c013425ecc 204 q1q1 = q1 * q1;
aktk 8:72c013425ecc 205 q1q2 = q1 * q2;
aktk 8:72c013425ecc 206 q1q3 = q1 * q3;
aktk 8:72c013425ecc 207 q2q2 = q2 * q2;
aktk 8:72c013425ecc 208 q2q3 = q2 * q3;
aktk 8:72c013425ecc 209 q3q3 = q3 * q3;
aktk 8:72c013425ecc 210
aktk 8:72c013425ecc 211 // Reference direction of Earth's magnetic field
aktk 8:72c013425ecc 212 //hx = mx * q0q0 - _2q0my * q3 + _2q0mz * q2 + mx * q1q1 + _2q1 * my * q2 + _2q1 * mz * q3 - mx * q2q2 - mx * q3q3;
aktk 8:72c013425ecc 213 //hx = mx * (q0q0 + q1q1 - q2q2 - q3q3) + 2.0f * my * (q1q2 - q0q3) + 2.0f * mz * (q1q3 + q0q2);
aktk 8:72c013425ecc 214 hx = mx
aktk 8:72c013425ecc 215 - 2.0f * mx * (q2q2 + q3q3)
aktk 8:72c013425ecc 216 + 2.0f * my * (q1q2 - q0q3)
aktk 8:72c013425ecc 217 + 2.0f * mz * (q1q3 + q0q2);
aktk 8:72c013425ecc 218
aktk 8:72c013425ecc 219 //hy = _2q0mx * q3 + my * q0q0 - _2q0mz * q1 + _2q1mx * q2 - my * q1q1 + my * q2q2 + _2q2 * mz * q3 - my * q3q3;
aktk 8:72c013425ecc 220 //hy = 2.0f * mx * (q0q3 + q1q2) + my * (q0q0 - q1q1 + q2q2 - q3q3) + 2.0f * mz * (q2q3 - q0q1);
aktk 8:72c013425ecc 221 hy = 2.0f * mx * (q1q2 + q0q3)
aktk 8:72c013425ecc 222 + my
aktk 8:72c013425ecc 223 - 2.0f * my * (q1q1 + q3q3)
aktk 8:72c013425ecc 224 + 2.0f * mz * (q2q3 - q0q1);
aktk 8:72c013425ecc 225
aktk 8:72c013425ecc 226 //hz = -_2q0mx * q2 + _2q0my * q1 + mz * q0q0 + _2q1mx * q3 - mz * q1q1 + _2q2 * my * q3 - mz * q2q2 + mz * q3q3;
aktk 8:72c013425ecc 227 hz = 2.0f * mx * (q1q3 - q0q2)
aktk 8:72c013425ecc 228 + 2.0f * my * (q2q3 + q0q1)
aktk 8:72c013425ecc 229 + mz
aktk 8:72c013425ecc 230 - 2.0f * mz * (q1q1 + q2q2);
aktk 8:72c013425ecc 231
aktk 8:72c013425ecc 232
aktk 8:72c013425ecc 233 bx = sqrt(hx * hx + hy * hy);
aktk 8:72c013425ecc 234 bz = hz;
aktk 8:72c013425ecc 235
aktk 8:72c013425ecc 236 _2bx = 2.0f * bx;
aktk 8:72c013425ecc 237 _2bz = 2.0f * bz;
aktk 8:72c013425ecc 238
aktk 8:72c013425ecc 239 //aux
aktk 8:72c013425ecc 240 float f_0 = _2q1 * q3 - _2q0 * q2 - ax;
aktk 8:72c013425ecc 241 float f_1 = _2q0 * q1 + _2q2 * q3 - ay;
aktk 8:72c013425ecc 242 float f_2 = 1.0f - _2q1 * q1 - _2q2 * q2 - az;
aktk 8:72c013425ecc 243 float f_3 = _2bx * (0.5f - q2q2 - q3q3) + _2bz * (q1q3 - q0q2) - mx;
aktk 8:72c013425ecc 244 float f_4 = _2bx * (q1q2 - q0q3) + _2bz * (q0q1 + q2q3) - my;
aktk 8:72c013425ecc 245 float f_5 = _2bx * (q0q2 + q1q3) + _2bz * (0.5f - q1q1 - q2q2) - mz;
aktk 8:72c013425ecc 246 float J_00or13 = _2q2; // J_00 negated in matrix multiplication
aktk 8:72c013425ecc 247 float J_01or12 = 2.0f * q3;
aktk 8:72c013425ecc 248 float J_02or11 = _2q0; // J_02 negated in matrix multiplication
aktk 8:72c013425ecc 249 float J_03or10 = _2q1;
aktk 8:72c013425ecc 250 float J_21 = 2.0f * J_03or10; // negated in matrix multiplication
aktk 8:72c013425ecc 251 float J_22 = 2.0f * J_00or13; // negated in matrix multiplication
aktk 8:72c013425ecc 252 float J_30 = _2bz*q2; // negated in matrix multiplication
aktk 8:72c013425ecc 253 float J_31 = _2bz*q3;
aktk 8:72c013425ecc 254 float J_32 = 2.0f * _2bx*q2 + _2bz*q0; // negated in matrix multiplication
aktk 8:72c013425ecc 255 float J_33 = 2.0f * _2bx*q3 - _2bz*q1; // negated in matrix multiplication
aktk 8:72c013425ecc 256 float J_40 = _2bx*q3 - _2bz*q1; // negated in matrix multiplication
aktk 8:72c013425ecc 257 float J_41 = _2bx*q2 + _2bz*q0;
aktk 8:72c013425ecc 258 float J_42 = _2bx*q1 + _2bz*q3;
aktk 8:72c013425ecc 259 float J_43 = _2bx*q0 - _2bz*q2; // negated in matrix multiplication
aktk 8:72c013425ecc 260 float J_50 = _2bx*q2;
aktk 8:72c013425ecc 261 float J_51 = _2bx*q3 - 2.0f * _2bz*q1;
aktk 8:72c013425ecc 262 float J_52 = _2bx*q0 - 2.0f * _2bz*q2;
aktk 8:72c013425ecc 263 float J_53 = _2bx*q1;
aktk 8:72c013425ecc 264
aktk 8:72c013425ecc 265 // Gradient decent algorithm corrective step
aktk 8:72c013425ecc 266 /*
aktk 8:72c013425ecc 267 s0 = -_2q2 * (2.0f * q1q3 - _2q0q2 - ax) + _2q1 * (2.0f * q0q1 + _2q2q3 - ay) - _2bz * q2 * (_2bx * (0.5f - q2q2 - q3q3) + _2bz * (q1q3 - q0q2) - mx) - (_2bx * q3 - _2bz * q1) * (_2bx * (q1q2 - q0q3) + _2bz * (q0q1 + q2q3) - my) + _2bx * q2 * (_2bx * (q0q2 + q1q3) + _2bz * (0.5f - q1q1 - q2q2) - mz);
aktk 8:72c013425ecc 268 s1 = _2q3 * (2.0f * q1q3 - _2q0q2 - ax) + _2q0 * (2.0f * q0q1 + _2q2q3 - ay) - 4.0f * q1 * (1 - 2.0f * q1q1 - 2.0f * q2q2 - az) + bz * q3 * (bx * (0.5f - q2q2 - q3q3) + bz * (q1q3 - q0q2) - mx) + (bx * q2 + bz * q0) * (bx * (q1q2 - q0q3) + bz * (q0q1 + q2q3) - my) + (bx * q3 - _2bz * q1) * (bx * (q0q2 + q1q3) + bz * (0.5f - q1q1 - q2q2) - mz);
aktk 8:72c013425ecc 269 s2 = -_2q0 * (2.0f * q1q3 - _2q0q2 - ax) + _2q3 * (2.0f * q0q1 + _2q2q3 - ay) - 4.0f * q2 * (1 - 2.0f * q1q1 - 2.0f * q2q2 - az) + (-_2bx * q2 - bz * q0) * (bx * (0.5f - q2q2 - q3q3) + bz * (q1q3 - q0q2) - mx) + (bx * q1 + bz * q3) * (bx * (q1q2 - q0q3) + bz * (q0q1 + q2q3) - my) + (bx * q0 - _2bz * q2) * (bx * (q0q2 + q1q3) + bz * (0.5f - q1q1 - q2q2) - mz);
aktk 8:72c013425ecc 270 s3 = _2q1 * (2.0f * q1q3 - _2q0q2 - ax) + _2q2 * (2.0f * q0q1 + _2q2q3 - ay) + (-_2bx * q3 + bz * q1) * (bx * (0.5f - q2q2 - q3q3) + bz * (q1q3 - q0q2) - mx) + (-bx * q0 + bz * q2) * (bx * (q1q2 - q0q3) + bz * (q0q1 + q2q3) - my) + bx * q1 * (bx * (q0q2 + q1q3) + bz * (0.5f - q1q1 - q2q2) - mz);
aktk 8:72c013425ecc 271 */
aktk 8:72c013425ecc 272 s0 = J_03or10 * f_1 - J_00or13 * f_0 - J_30 * f_3 - J_40 * f_4 + J_50 * f_5;
aktk 8:72c013425ecc 273 s1 = J_01or12 * f_0 + J_02or11 * f_1 - J_21 * f_2 + J_31 * f_3 + J_41 * f_4 + J_51 * f_5;
aktk 8:72c013425ecc 274 s2 = J_01or12 * f_1 - J_22 * f_2 - J_02or11 * f_0 - J_32 * f_3 + J_42 * f_4 + J_52 * f_5;
aktk 8:72c013425ecc 275 s3 = J_03or10 * f_0 + J_00or13 * f_1 - J_33 * f_3 - J_43 * f_4 + J_53 * f_5;
aktk 8:72c013425ecc 276
aktk 8:72c013425ecc 277 recipNorm = 1.0f / sqrt(s0 * s0 + s1 * s1 + s2 * s2 + s3 * s3); // normalise step magnitude
aktk 8:72c013425ecc 278 s0 *= recipNorm;
aktk 8:72c013425ecc 279 s1 *= recipNorm;
aktk 8:72c013425ecc 280 s2 *= recipNorm;
aktk 8:72c013425ecc 281 s3 *= recipNorm;
aktk 8:72c013425ecc 282
aktk 8:72c013425ecc 283 }
aktk 8:72c013425ecc 284
aktk 8:72c013425ecc 285 // Integrate rate of change of quaternion to yield quaternion
aktk 8:72c013425ecc 286 newTime = (unsigned int)madgwickTimer.read_us();
aktk 8:72c013425ecc 287 deltaT = (newTime - oldTime) / 1000000.0f;
aktk 8:72c013425ecc 288 deltaT = fabs(deltaT);
aktk 8:72c013425ecc 289 oldTime = newTime;
aktk 8:72c013425ecc 290
aktk 8:72c013425ecc 291 // compute angular estimated direction of the gyroscope error
aktk 8:72c013425ecc 292 float w_err_x = _2q0 * s1 - _2q1 * s0 - _2q2 * s3 + _2q3 * s2;
aktk 8:72c013425ecc 293 float w_err_y = _2q0 * s2 + _2q1 * s3 - _2q2 * s0 - _2q3 * s1;
aktk 8:72c013425ecc 294 float w_err_z = _2q0 * s3 - _2q1 * s2 + _2q2 * s1 - _2q3 * s0;
aktk 8:72c013425ecc 295 // compute and remove the gyroscope baises
aktk 8:72c013425ecc 296 w_bx += w_err_x * deltaT * zeta;
aktk 8:72c013425ecc 297 w_by += w_err_y * deltaT * zeta;
aktk 8:72c013425ecc 298 w_bz += w_err_z * deltaT * zeta;
aktk 8:72c013425ecc 299 gx -= w_bx;
aktk 8:72c013425ecc 300 gy -= w_by;
aktk 8:72c013425ecc 301 gz -= w_bz;
aktk 8:72c013425ecc 302
aktk 8:72c013425ecc 303
aktk 8:72c013425ecc 304
aktk 8:72c013425ecc 305 // Rate of change of quaternion from gyroscope
aktk 8:72c013425ecc 306 qDot1 = 0.5f * (-q1 * gx - q2 * gy - q3 * gz);
aktk 8:72c013425ecc 307 qDot2 = 0.5f * (q0 * gx + q2 * gz - q3 * gy);
aktk 8:72c013425ecc 308 qDot3 = 0.5f * (q0 * gy - q1 * gz + q3 * gx);
aktk 8:72c013425ecc 309 qDot4 = 0.5f * (q0 * gz + q1 * gy - q2 * gx);
aktk 8:72c013425ecc 310
aktk 8:72c013425ecc 311 q0 += (qDot1 - beta * s0) * deltaT;//(1.0f / sampleFreq);
aktk 8:72c013425ecc 312 q1 += (qDot2 - beta * s1) * deltaT;//(1.0f / sampleFreq);
aktk 8:72c013425ecc 313 q2 += (qDot3 - beta * s2) * deltaT;//(1.0f / sampleFreq);
aktk 8:72c013425ecc 314 q3 += (qDot4 - beta * s3) * deltaT;//(1.0f / sampleFreq);
aktk 8:72c013425ecc 315
aktk 8:72c013425ecc 316 // Normalise quaternion
aktk 8:72c013425ecc 317 recipNorm = 1.0f / sqrt(q0 * q0 + q1 * q1 + q2 * q2 + q3 * q3);
aktk 8:72c013425ecc 318 q0 *= recipNorm;
aktk 8:72c013425ecc 319 q1 *= recipNorm;
aktk 8:72c013425ecc 320 q2 *= recipNorm;
aktk 8:72c013425ecc 321 q3 *= recipNorm;
aktk 8:72c013425ecc 322
aktk 8:72c013425ecc 323 q.w = q0;
aktk 8:72c013425ecc 324 q.x = q1;
aktk 8:72c013425ecc 325 q.y = q2;
aktk 8:72c013425ecc 326 q.z = q3;
aktk 8:72c013425ecc 327 }
aktk 8:72c013425ecc 328
aktk 8:72c013425ecc 329 inline void MadgwickFilter::MadgwickAHRSupdate(float *gyro, float *acc, float *mag)
aktk 8:72c013425ecc 330 {
aktk 8:72c013425ecc 331
aktk 8:72c013425ecc 332 static float gx = 0, gy = 0, gz = 0.0f, ax = 0.0f, ay = 0.0f, az = 0.0f, mx = 0.0f, my = 0.0f, mz = 0.0f;
Gaku0606 6:eff5ebc4ea13 333 static float acc_norm;
Gaku0606 6:eff5ebc4ea13 334 static float deltaT = 0.0f;
Gaku0606 0:c160cac4c370 335 static unsigned int newTime = 0, oldTime = 0;
Gaku0606 6:eff5ebc4ea13 336 static float recipNorm;
Gaku0606 6:eff5ebc4ea13 337 static float s0, s1, s2, s3;
Gaku0606 6:eff5ebc4ea13 338 static float qDot1, qDot2, qDot3, qDot4;
Gaku0606 6:eff5ebc4ea13 339 static float hx, hy;
aktk 8:72c013425ecc 340 static float _2q0mx, _2q0my, _2q0mz, _2q1mx, bx, bz, _2bx, _2bz, _2q0, _2q1, _2q2, _2q3, _2q0q2, _2q2q3, q0q0, q0q1, q0q2, q0q3, q1q1, q1q2, q1q3, q2q2, q2q3, q3q3;
aktk 8:72c013425ecc 341
aktk 8:72c013425ecc 342 gx = gyro[0];
aktk 8:72c013425ecc 343 gy = gyro[1];
aktk 8:72c013425ecc 344 gz = gyro[2];
aktk 8:72c013425ecc 345 ax = acc[0];
aktk 8:72c013425ecc 346 ay = acc[1];
aktk 8:72c013425ecc 347 az = acc[2];
aktk 8:72c013425ecc 348 mx = mag[0];
aktk 8:72c013425ecc 349 my = mag[1];
aktk 8:72c013425ecc 350 mz = mag[2];
Gaku0606 0:c160cac4c370 351
Gaku0606 0:c160cac4c370 352 // Use IMU algorithm if magnetometer measurement invalid (avoids NaN in magnetometer normalisation)
Gaku0606 0:c160cac4c370 353 if((mx == 0.0f) && (my == 0.0f) && (mz == 0.0f)) {
Gaku0606 0:c160cac4c370 354 MadgwickAHRSupdateIMU(gx, gy, gz, ax, ay, az);
Gaku0606 0:c160cac4c370 355 return;
Gaku0606 0:c160cac4c370 356 }
Gaku0606 0:c160cac4c370 357
Gaku0606 0:c160cac4c370 358 // Rate of change of quaternion from gyroscope
Gaku0606 0:c160cac4c370 359 qDot1 = 0.5f * (-q1 * gx - q2 * gy - q3 * gz);
Gaku0606 0:c160cac4c370 360 qDot2 = 0.5f * (q0 * gx + q2 * gz - q3 * gy);
Gaku0606 0:c160cac4c370 361 qDot3 = 0.5f * (q0 * gy - q1 * gz + q3 * gx);
Gaku0606 0:c160cac4c370 362 qDot4 = 0.5f * (q0 * gz + q1 * gy - q2 * gx);
Gaku0606 0:c160cac4c370 363
Gaku0606 0:c160cac4c370 364 // Compute feedback only if accelerometer measurement valid (avoids NaN in accelerometer normalisation)
Gaku0606 0:c160cac4c370 365 if(!((ax == 0.0f) && (ay == 0.0f) && (az == 0.0f))) {
Gaku0606 0:c160cac4c370 366
Gaku0606 0:c160cac4c370 367 // Normalise accelerometer measurement
Gaku0606 5:1e6fecaea25e 368 acc_norm = sqrt(ax * ax + ay * ay + az * az);
Gaku0606 6:eff5ebc4ea13 369 recipNorm = 1.0f / acc_norm;
Gaku0606 0:c160cac4c370 370 ax *= recipNorm;
Gaku0606 0:c160cac4c370 371 ay *= recipNorm;
aktk 8:72c013425ecc 372 az *= recipNorm;
Gaku0606 0:c160cac4c370 373
Gaku0606 0:c160cac4c370 374 // Normalise magnetometer measurement
Gaku0606 6:eff5ebc4ea13 375 recipNorm = 1.0f / sqrt(mx * mx + my * my + mz * mz);
Gaku0606 0:c160cac4c370 376 mx *= recipNorm;
Gaku0606 0:c160cac4c370 377 my *= recipNorm;
Gaku0606 0:c160cac4c370 378 mz *= recipNorm;
Gaku0606 0:c160cac4c370 379
Gaku0606 0:c160cac4c370 380 // Auxiliary variables to avoid repeated arithmetic
Gaku0606 0:c160cac4c370 381 _2q0mx = 2.0f * q0 * mx;
Gaku0606 0:c160cac4c370 382 _2q0my = 2.0f * q0 * my;
Gaku0606 0:c160cac4c370 383 _2q0mz = 2.0f * q0 * mz;
Gaku0606 0:c160cac4c370 384 _2q1mx = 2.0f * q1 * mx;
Gaku0606 0:c160cac4c370 385 _2q0 = 2.0f * q0;
Gaku0606 0:c160cac4c370 386 _2q1 = 2.0f * q1;
Gaku0606 0:c160cac4c370 387 _2q2 = 2.0f * q2;
Gaku0606 0:c160cac4c370 388 _2q3 = 2.0f * q3;
Gaku0606 0:c160cac4c370 389 _2q0q2 = 2.0f * q0 * q2;
Gaku0606 0:c160cac4c370 390 _2q2q3 = 2.0f * q2 * q3;
Gaku0606 0:c160cac4c370 391 q0q0 = q0 * q0;
Gaku0606 0:c160cac4c370 392 q0q1 = q0 * q1;
Gaku0606 0:c160cac4c370 393 q0q2 = q0 * q2;
Gaku0606 0:c160cac4c370 394 q0q3 = q0 * q3;
Gaku0606 0:c160cac4c370 395 q1q1 = q1 * q1;
Gaku0606 0:c160cac4c370 396 q1q2 = q1 * q2;
Gaku0606 0:c160cac4c370 397 q1q3 = q1 * q3;
Gaku0606 0:c160cac4c370 398 q2q2 = q2 * q2;
Gaku0606 0:c160cac4c370 399 q2q3 = q2 * q3;
Gaku0606 0:c160cac4c370 400 q3q3 = q3 * q3;
Gaku0606 0:c160cac4c370 401
Gaku0606 0:c160cac4c370 402 // Reference direction of Earth's magnetic field
Gaku0606 0:c160cac4c370 403 hx = mx * q0q0 - _2q0my * q3 + _2q0mz * q2 + mx * q1q1 + _2q1 * my * q2 + _2q1 * mz * q3 - mx * q2q2 - mx * q3q3;
Gaku0606 0:c160cac4c370 404 hy = _2q0mx * q3 + my * q0q0 - _2q0mz * q1 + _2q1mx * q2 - my * q1q1 + my * q2q2 + _2q2 * mz * q3 - my * q3q3;
aktk 8:72c013425ecc 405 bx = sqrt(hx * hx + hy * hy);
aktk 8:72c013425ecc 406 bz = -_2q0mx * q2 + _2q0my * q1 + mz * q0q0 + _2q1mx * q3 - mz * q1q1 + _2q2 * my * q3 - mz * q2q2 + mz * q3q3;
aktk 8:72c013425ecc 407 _2bx = 2.0f * bx;
aktk 8:72c013425ecc 408 _2bz = 2.0f * bz;
Gaku0606 0:c160cac4c370 409
Gaku0606 0:c160cac4c370 410 // Gradient decent algorithm corrective step
aktk 8:72c013425ecc 411 s0 = -_2q2 * (2.0f * q1q3 - _2q0q2 - ax) + _2q1 * (2.0f * q0q1 + _2q2q3 - ay) - bz * q2 * (bx * (0.5f - q2q2 - q3q3) + bz * (q1q3 - q0q2) - mx) + (-bx * q3 + bz * q1) * (bx * (q1q2 - q0q3) + bz * (q0q1 + q2q3) - my) + bx * q2 * (bx * (q0q2 + q1q3) + bz * (0.5f - q1q1 - q2q2) - mz);
aktk 8:72c013425ecc 412 s1 = _2q3 * (2.0f * q1q3 - _2q0q2 - ax) + _2q0 * (2.0f * q0q1 + _2q2q3 - ay) - 4.0f * q1 * (1 - 2.0f * q1q1 - 2.0f * q2q2 - az) + bz * q3 * (bx * (0.5f - q2q2 - q3q3) + bz * (q1q3 - q0q2) - mx) + (bx * q2 + bz * q0) * (bx * (q1q2 - q0q3) + bz * (q0q1 + q2q3) - my) + (bx * q3 - _2bz * q1) * (bx * (q0q2 + q1q3) + bz * (0.5f - q1q1 - q2q2) - mz);
aktk 8:72c013425ecc 413 s2 = -_2q0 * (2.0f * q1q3 - _2q0q2 - ax) + _2q3 * (2.0f * q0q1 + _2q2q3 - ay) - 4.0f * q2 * (1 - 2.0f * q1q1 - 2.0f * q2q2 - az) + (-_2bx * q2 - bz * q0) * (bx * (0.5f - q2q2 - q3q3) + bz * (q1q3 - q0q2) - mx) + (bx * q1 + bz * q3) * (bx * (q1q2 - q0q3) + bz * (q0q1 + q2q3) - my) + (bx * q0 - _2bz * q2) * (bx * (q0q2 + q1q3) + bz * (0.5f - q1q1 - q2q2) - mz);
aktk 8:72c013425ecc 414 s3 = _2q1 * (2.0f * q1q3 - _2q0q2 - ax) + _2q2 * (2.0f * q0q1 + _2q2q3 - ay) + (-_2bx * q3 + bz * q1) * (bx * (0.5f - q2q2 - q3q3) + bz * (q1q3 - q0q2) - mx) + (-bx * q0 + bz * q2) * (bx * (q1q2 - q0q3) + bz * (q0q1 + q2q3) - my) + bx * q1 * (bx * (q0q2 + q1q3) + bz * (0.5f - q1q1 - q2q2) - mz);
Gaku0606 6:eff5ebc4ea13 415 recipNorm = 1.0f / sqrt(s0 * s0 + s1 * s1 + s2 * s2 + s3 * s3); // normalise step magnitude
Gaku0606 0:c160cac4c370 416 s0 *= recipNorm;
Gaku0606 0:c160cac4c370 417 s1 *= recipNorm;
Gaku0606 0:c160cac4c370 418 s2 *= recipNorm;
Gaku0606 0:c160cac4c370 419 s3 *= recipNorm;
Gaku0606 0:c160cac4c370 420
Gaku0606 6:eff5ebc4ea13 421 float deltaA = fabs(acc_norm - 1.00f);
Gaku0606 5:1e6fecaea25e 422 //beta = 0.1*exp(-1.0*deltaA*deltaA);
Gaku0606 5:1e6fecaea25e 423 //beta = 0.3*exp(-20.0*deltaA*deltaA);
Gaku0606 7:c20656d96585 424 //beta = beta*exp(-30.0f*deltaA*deltaA);
Gaku0606 5:1e6fecaea25e 425 //printf("%f\r\n", beta);
Gaku0606 6:eff5ebc4ea13 426 //beta = 1.0;
Gaku0606 5:1e6fecaea25e 427 //if(deltaA > 0.3) beta = 0.0;
Gaku0606 0:c160cac4c370 428 // Apply feedback step
Gaku0606 0:c160cac4c370 429 qDot1 -= beta * s0;
Gaku0606 0:c160cac4c370 430 qDot2 -= beta * s1;
Gaku0606 0:c160cac4c370 431 qDot3 -= beta * s2;
Gaku0606 0:c160cac4c370 432 qDot4 -= beta * s3;
Gaku0606 0:c160cac4c370 433 }
Gaku0606 0:c160cac4c370 434
Gaku0606 0:c160cac4c370 435 // Integrate rate of change of quaternion to yield quaternion
Gaku0606 0:c160cac4c370 436 newTime = (unsigned int)madgwickTimer.read_us();
Gaku0606 6:eff5ebc4ea13 437 deltaT = (newTime - oldTime) / 1000000.0f;
Gaku0606 0:c160cac4c370 438 deltaT = fabs(deltaT);
Gaku0606 0:c160cac4c370 439 oldTime = newTime;
aktk 8:72c013425ecc 440
Gaku0606 0:c160cac4c370 441 q0 += qDot1 * deltaT;//(1.0f / sampleFreq);
Gaku0606 0:c160cac4c370 442 q1 += qDot2 * deltaT;//(1.0f / sampleFreq);
Gaku0606 0:c160cac4c370 443 q2 += qDot3 * deltaT;//(1.0f / sampleFreq);
Gaku0606 0:c160cac4c370 444 q3 += qDot4 * deltaT;//(1.0f / sampleFreq);
Gaku0606 0:c160cac4c370 445
Gaku0606 0:c160cac4c370 446 // Normalise quaternion
Gaku0606 6:eff5ebc4ea13 447 recipNorm = 1.0f / sqrt(q0 * q0 + q1 * q1 + q2 * q2 + q3 * q3);
Gaku0606 0:c160cac4c370 448 q0 *= recipNorm;
Gaku0606 0:c160cac4c370 449 q1 *= recipNorm;
Gaku0606 0:c160cac4c370 450 q2 *= recipNorm;
Gaku0606 0:c160cac4c370 451 q3 *= recipNorm;
aktk 8:72c013425ecc 452
Gaku0606 0:c160cac4c370 453 q.w = q0;
Gaku0606 0:c160cac4c370 454 q.x = q1;
Gaku0606 0:c160cac4c370 455 q.y = q2;
Gaku0606 0:c160cac4c370 456 q.z = q3;
Gaku0606 0:c160cac4c370 457 }
Gaku0606 0:c160cac4c370 458
aktk 8:72c013425ecc 459 //---------------------------------------------------------------------------------------------------
aktk 8:72c013425ecc 460 // IMU algorithm update
Gaku0606 7:c20656d96585 461
aktk 8:72c013425ecc 462 inline void MadgwickFilter::MadgwickAHRSupdateIMU(float gx, float gy, float gz, float ax, float ay, float az)
aktk 8:72c013425ecc 463 {
Gaku0606 7:c20656d96585 464 // Rate of change of quaternion from gyroscope
Gaku0606 7:c20656d96585 465 qDot1 = 0.5f * (-q1 * gx - q2 * gy - q3 * gz);
Gaku0606 7:c20656d96585 466 qDot2 = 0.5f * (q0 * gx + q2 * gz - q3 * gy);
Gaku0606 7:c20656d96585 467 qDot3 = 0.5f * (q0 * gy - q1 * gz + q3 * gx);
Gaku0606 7:c20656d96585 468 qDot4 = 0.5f * (q0 * gz + q1 * gy - q2 * gx);
Gaku0606 7:c20656d96585 469
Gaku0606 7:c20656d96585 470 // Compute feedback only if accelerometer measurement valid (avoids NaN in accelerometer normalisation)
Gaku0606 7:c20656d96585 471 if(!((ax == 0.0f) && (ay == 0.0f) && (az == 0.0f))) {
Gaku0606 7:c20656d96585 472
Gaku0606 7:c20656d96585 473 // Normalise accelerometer measurement
Gaku0606 7:c20656d96585 474 acc_norm = sqrt(ax * ax + ay * ay + az * az);
Gaku0606 7:c20656d96585 475 recipNorm = 1.0f / acc_norm;
Gaku0606 7:c20656d96585 476 ax *= recipNorm;
Gaku0606 7:c20656d96585 477 ay *= recipNorm;
aktk 8:72c013425ecc 478 az *= recipNorm;
Gaku0606 0:c160cac4c370 479
Gaku0606 0:c160cac4c370 480 // Auxiliary variables to avoid repeated arithmetic
Gaku0606 0:c160cac4c370 481 _2q0 = 2.0f * q0;
Gaku0606 0:c160cac4c370 482 _2q1 = 2.0f * q1;
Gaku0606 0:c160cac4c370 483 _2q2 = 2.0f * q2;
Gaku0606 0:c160cac4c370 484 _2q3 = 2.0f * q3;
Gaku0606 0:c160cac4c370 485 _4q0 = 4.0f * q0;
Gaku0606 0:c160cac4c370 486 _4q1 = 4.0f * q1;
Gaku0606 0:c160cac4c370 487 _4q2 = 4.0f * q2;
Gaku0606 0:c160cac4c370 488 _8q1 = 8.0f * q1;
Gaku0606 0:c160cac4c370 489 _8q2 = 8.0f * q2;
Gaku0606 0:c160cac4c370 490 q0q0 = q0 * q0;
Gaku0606 0:c160cac4c370 491 q1q1 = q1 * q1;
Gaku0606 0:c160cac4c370 492 q2q2 = q2 * q2;
Gaku0606 0:c160cac4c370 493 q3q3 = q3 * q3;
Gaku0606 0:c160cac4c370 494
Gaku0606 0:c160cac4c370 495 // Gradient decent algorithm corrective step
aktk 8:72c013425ecc 496 s0 = _4q0* q2q2 + _2q2 * ax + _4q0 * q1q1 - _2q1 * ay;
Gaku0606 0:c160cac4c370 497 s1 = _4q1 * q3q3 - _2q3 * ax + 4.0f * q0q0 * q1 - _2q0 * ay - _4q1 + _8q1 * q1q1 + _8q1 * q2q2 + _4q1 * az;
Gaku0606 0:c160cac4c370 498 s2 = 4.0f * q0q0 * q2 + _2q0 * ax + _4q2 * q3q3 - _2q3 * ay - _4q2 + _8q2 * q1q1 + _8q2 * q2q2 + _4q2 * az;
Gaku0606 0:c160cac4c370 499 s3 = 4.0f * q1q1 * q3 - _2q1 * ax + 4.0f * q2q2 * q3 - _2q2 * ay;
Gaku0606 6:eff5ebc4ea13 500 recipNorm = 1.0f / sqrt(s0 * s0 + s1 * s1 + s2 * s2 + s3 * s3); // normalise step magnitude
Gaku0606 0:c160cac4c370 501 s0 *= recipNorm;
Gaku0606 0:c160cac4c370 502 s1 *= recipNorm;
Gaku0606 0:c160cac4c370 503 s2 *= recipNorm;
Gaku0606 0:c160cac4c370 504 s3 *= recipNorm;
Gaku0606 0:c160cac4c370 505
Gaku0606 0:c160cac4c370 506 // Apply feedback step
aktk 8:72c013425ecc 507 //static float deltaA;
aktk 8:72c013425ecc 508 //deltaA = fabs(acc_norm - 1.00f);
Gaku0606 5:1e6fecaea25e 509 //beta = 0.5*exp(-20.0*deltaA*deltaA);
aktk 8:72c013425ecc 510 //if(deltaA > 0.3f) beta = 0.0f;
aktk 8:72c013425ecc 511 //else beta = 0.1f;
Gaku0606 0:c160cac4c370 512 qDot1 -= beta * s0;
Gaku0606 0:c160cac4c370 513 qDot2 -= beta * s1;
Gaku0606 0:c160cac4c370 514 qDot3 -= beta * s2;
Gaku0606 0:c160cac4c370 515 qDot4 -= beta * s3;
Gaku0606 0:c160cac4c370 516 }
Gaku0606 0:c160cac4c370 517
Gaku0606 0:c160cac4c370 518 // Integrate rate of change of quaternion to yield quaternion
aktk 8:72c013425ecc 519
Gaku0606 0:c160cac4c370 520 newTime = (unsigned int)madgwickTimer.read_us();
aktk 8:72c013425ecc 521 deltaT = ((newTime - oldTime) % 0xFFFFFFFF) / 1000000.0f;
Gaku0606 0:c160cac4c370 522 oldTime = newTime;
aktk 8:72c013425ecc 523 deltaT = fabs(deltaT);
aktk 8:72c013425ecc 524
aktk 8:72c013425ecc 525 q0 += qDot1 * deltaT;
aktk 8:72c013425ecc 526 q1 += qDot2 * deltaT;
aktk 8:72c013425ecc 527 q2 += qDot3 * deltaT;
aktk 8:72c013425ecc 528 q3 += qDot4 * deltaT;
Gaku0606 0:c160cac4c370 529
Gaku0606 0:c160cac4c370 530 // Normalise quaternion
Gaku0606 6:eff5ebc4ea13 531 recipNorm = 1.0f / sqrt(q0 * q0 + q1 * q1 + q2 * q2 + q3 * q3);
Gaku0606 0:c160cac4c370 532 q0 *= recipNorm;
Gaku0606 0:c160cac4c370 533 q1 *= recipNorm;
Gaku0606 0:c160cac4c370 534 q2 *= recipNorm;
Gaku0606 0:c160cac4c370 535 q3 *= recipNorm;
Gaku0606 0:c160cac4c370 536
Gaku0606 0:c160cac4c370 537 q.w = q0;
Gaku0606 0:c160cac4c370 538 q.x = q1;
Gaku0606 0:c160cac4c370 539 q.y = q2;
Gaku0606 0:c160cac4c370 540 q.z = q3;
Gaku0606 0:c160cac4c370 541 }
Gaku0606 0:c160cac4c370 542
Gaku0606 0:c160cac4c370 543
Gaku0606 0:c160cac4c370 544 #endif