Bremen Team - Hangar
Implemented first Hangar-Service
Dependencies: CalibrateMagneto QuaternionMath
Fork of
SML2
by 
TobyRich GmbH
SensorFusion.cpp@35:fb6e4601adf3, 2015-05-08 (annotated)
- Committer:
- pvaibhav
- Date:
- Fri May 08 06:20:18 2015 +0000
- Revision:
- 35:fb6e4601adf3
- Parent:
- 34:01dec68de3ed
- Child:
- 37:63d355f2cf6a
white LED control added, 6-axis sensor fusion added (enabled by default)
Who changed what in which revision?
| User | Revision | Line number | New contents of line |
|---|---|---|---|
| pvaibhav | 15:4488660e1a3b | 1 | #include "SensorFusion.h" |
| pvaibhav | 15:4488660e1a3b | 2 | |
| pvaibhav | 15:4488660e1a3b | 3 | #define DEBUG "SensorFusion" |
| pvaibhav | 15:4488660e1a3b | 4 | #include "Logger.h" |
| pvaibhav | 15:4488660e1a3b | 5 | |
| pvaibhav | 34:01dec68de3ed | 6 | #include "Utils.h" |
| pvaibhav | 35:fb6e4601adf3 | 7 | #define SIXAXIS |
| pvaibhav | 34:01dec68de3ed | 8 | |
| pvaibhav | 21:5a0c9406e119 | 9 | SensorFusion::SensorFusion(I2C &i2c) : |
| pvaibhav | 21:5a0c9406e119 | 10 | delegate(&defaultDelegate), |
| pvaibhav | 21:5a0c9406e119 | 11 | accel(i2c), gyro(i2c), magneto(i2c), |
| pvaibhav | 15:4488660e1a3b | 12 | q(1, 0, 0, 0), // output quaternion |
| pvaibhav | 15:4488660e1a3b | 13 | deltat(0.010), // sec |
| pvaibhav | 34:01dec68de3ed | 14 | beta(0.5), // correction gain |
| pvaibhav | 34:01dec68de3ed | 15 | fused(0, 0, 0) |
| pvaibhav | 15:4488660e1a3b | 16 | { |
| pvaibhav | 20:503cbe360419 | 17 | } |
| pvaibhav | 20:503cbe360419 | 18 | |
| pvaibhav | 20:503cbe360419 | 19 | void SensorFusion::setDelegate(SensorFusion::Delegate &d) |
| pvaibhav | 20:503cbe360419 | 20 | { |
| pvaibhav | 20:503cbe360419 | 21 | delegate = &d; |
| pvaibhav | 15:4488660e1a3b | 22 | } |
| pvaibhav | 15:4488660e1a3b | 23 | |
| pvaibhav | 15:4488660e1a3b | 24 | bool SensorFusion::start() |
| pvaibhav | 15:4488660e1a3b | 25 | { |
| pvaibhav | 15:4488660e1a3b | 26 | accel.powerOn(); |
| pvaibhav | 15:4488660e1a3b | 27 | accel.start(); |
| pvaibhav | 15:4488660e1a3b | 28 | |
| pvaibhav | 35:fb6e4601adf3 | 29 | #ifdef NINEAXIS |
| pvaibhav | 15:4488660e1a3b | 30 | magneto.powerOn(); |
| pvaibhav | 15:4488660e1a3b | 31 | if (magneto.performSelfTest() == false) { |
| pvaibhav | 15:4488660e1a3b | 32 | return false; |
| pvaibhav | 15:4488660e1a3b | 33 | } |
| pvaibhav | 15:4488660e1a3b | 34 | magneto.start(); |
| pvaibhav | 35:fb6e4601adf3 | 35 | #endif |
| pvaibhav | 15:4488660e1a3b | 36 | |
| pvaibhav | 15:4488660e1a3b | 37 | // Since everything is synced to gyro interrupt, start it last |
| pvaibhav | 15:4488660e1a3b | 38 | gyro.setDelegate(*this); |
| pvaibhav | 15:4488660e1a3b | 39 | gyro.powerOn(); |
| pvaibhav | 15:4488660e1a3b | 40 | gyro.start(); |
| pvaibhav | 15:4488660e1a3b | 41 | |
| pvaibhav | 15:4488660e1a3b | 42 | return true; |
| pvaibhav | 15:4488660e1a3b | 43 | } |
| pvaibhav | 15:4488660e1a3b | 44 | |
| pvaibhav | 15:4488660e1a3b | 45 | void SensorFusion::stop() |
| pvaibhav | 15:4488660e1a3b | 46 | { |
| pvaibhav | 15:4488660e1a3b | 47 | gyro.stop(); |
| pvaibhav | 35:fb6e4601adf3 | 48 | #ifdef NINEAXIS |
| pvaibhav | 15:4488660e1a3b | 49 | magneto.stop(); |
| pvaibhav | 35:fb6e4601adf3 | 50 | #endif |
| pvaibhav | 15:4488660e1a3b | 51 | accel.stop(); |
| pvaibhav | 15:4488660e1a3b | 52 | |
| pvaibhav | 15:4488660e1a3b | 53 | gyro.powerOff(); |
| pvaibhav | 35:fb6e4601adf3 | 54 | #ifdef NINEAXIS |
| pvaibhav | 15:4488660e1a3b | 55 | magneto.powerOff(); |
| pvaibhav | 35:fb6e4601adf3 | 56 | #endif |
| pvaibhav | 15:4488660e1a3b | 57 | accel.powerOff(); |
| pvaibhav | 15:4488660e1a3b | 58 | } |
| pvaibhav | 15:4488660e1a3b | 59 | |
| pvaibhav | 15:4488660e1a3b | 60 | static float const deg_to_radian = 0.0174532925f; |
| pvaibhav | 15:4488660e1a3b | 61 | |
| pvaibhav | 15:4488660e1a3b | 62 | void SensorFusion::sensorUpdate(Vector3 gyro_degrees) |
| pvaibhav | 15:4488660e1a3b | 63 | { |
| pvaibhav | 31:d65576185bdf | 64 | |
| pvaibhav | 15:4488660e1a3b | 65 | Vector3 const gyro_reading = gyro_degrees * deg_to_radian; |
| pvaibhav | 31:d65576185bdf | 66 | |
| pvaibhav | 15:4488660e1a3b | 67 | Vector3 const accel_reading = accel.read(); |
| pvaibhav | 35:fb6e4601adf3 | 68 | #ifdef NINEAXIS |
| pvaibhav | 15:4488660e1a3b | 69 | Vector3 const magneto_reading = magneto.read(); |
| pvaibhav | 15:4488660e1a3b | 70 | updateFilter( accel_reading.x, accel_reading.y, accel_reading.z, |
| pvaibhav | 15:4488660e1a3b | 71 | gyro_reading.x, gyro_reading.y, gyro_reading.z, |
| pvaibhav | 15:4488660e1a3b | 72 | magneto_reading.x, magneto_reading.y, magneto_reading.z); |
| pvaibhav | 35:fb6e4601adf3 | 73 | #else |
| pvaibhav | 35:fb6e4601adf3 | 74 | Vector3 const magneto_reading(0, 0, 0); |
| pvaibhav | 35:fb6e4601adf3 | 75 | updateFilter( accel_reading.x, accel_reading.y, accel_reading.z, |
| pvaibhav | 35:fb6e4601adf3 | 76 | gyro_reading.x, gyro_reading.y, gyro_reading.z); |
| pvaibhav | 35:fb6e4601adf3 | 77 | #endif |
| pvaibhav | 15:4488660e1a3b | 78 | |
| pvaibhav | 34:01dec68de3ed | 79 | delegate->sensorTick(deltat, q.getEulerAngles(), accel_reading, magneto_reading, gyro_degrees, q); |
| pvaibhav | 34:01dec68de3ed | 80 | } |
| pvaibhav | 34:01dec68de3ed | 81 | |
| pvaibhav | 34:01dec68de3ed | 82 | void SensorFusion::getMagnetometerCalibration(Vector3 &min, Vector3 &max) |
| pvaibhav | 34:01dec68de3ed | 83 | { |
| pvaibhav | 34:01dec68de3ed | 84 | magneto.getCalibration(min, max); |
| pvaibhav | 15:4488660e1a3b | 85 | } |
| pvaibhav | 15:4488660e1a3b | 86 | |
| pvaibhav | 35:fb6e4601adf3 | 87 | // 6 axis version |
| pvaibhav | 35:fb6e4601adf3 | 88 | void SensorFusion::updateFilter(float ax, float ay, float az, float gx, float gy, float gz) |
| pvaibhav | 35:fb6e4601adf3 | 89 | { |
| pvaibhav | 35:fb6e4601adf3 | 90 | float q0 = q.w, q1 = q.v.x, q2 = q.v.y, q3 = q.v.z; // short name local variable for readability |
| pvaibhav | 35:fb6e4601adf3 | 91 | |
| pvaibhav | 35:fb6e4601adf3 | 92 | float recipNorm; |
| pvaibhav | 35:fb6e4601adf3 | 93 | float s0, s1, s2, s3; |
| pvaibhav | 35:fb6e4601adf3 | 94 | float qDot1, qDot2, qDot3, qDot4; |
| pvaibhav | 35:fb6e4601adf3 | 95 | float _2q0, _2q1, _2q2, _2q3, _4q0, _4q1, _4q2 ,_8q1, _8q2, q0q0, q1q1, q2q2, q3q3; |
| pvaibhav | 35:fb6e4601adf3 | 96 | |
| pvaibhav | 35:fb6e4601adf3 | 97 | // Rate of change of quaternion from gyroscope |
| pvaibhav | 35:fb6e4601adf3 | 98 | qDot1 = 0.5 * (-q1 * gx - q2 * gy - q3 * gz); |
| pvaibhav | 35:fb6e4601adf3 | 99 | qDot2 = 0.5 * (q0 * gx + q2 * gz - q3 * gy); |
| pvaibhav | 35:fb6e4601adf3 | 100 | qDot3 = 0.5 * (q0 * gy - q1 * gz + q3 * gx); |
| pvaibhav | 35:fb6e4601adf3 | 101 | qDot4 = 0.5 * (q0 * gz + q1 * gy - q2 * gx); |
| pvaibhav | 35:fb6e4601adf3 | 102 | |
| pvaibhav | 35:fb6e4601adf3 | 103 | // Compute feedback only if accelerometer measurement valid (avoids NaN in accelerometer normalisation) |
| pvaibhav | 35:fb6e4601adf3 | 104 | if(!((ax == 0.0) && (ay == 0.0) && (az == 0.0))) { |
| pvaibhav | 35:fb6e4601adf3 | 105 | |
| pvaibhav | 35:fb6e4601adf3 | 106 | // Normalise accelerometer measurement |
| pvaibhav | 35:fb6e4601adf3 | 107 | recipNorm = 1.0 / sqrt(ax * ax + ay * ay + az * az); |
| pvaibhav | 35:fb6e4601adf3 | 108 | ax *= recipNorm; |
| pvaibhav | 35:fb6e4601adf3 | 109 | ay *= recipNorm; |
| pvaibhav | 35:fb6e4601adf3 | 110 | az *= recipNorm; |
| pvaibhav | 35:fb6e4601adf3 | 111 | |
| pvaibhav | 35:fb6e4601adf3 | 112 | // Auxiliary variables to avoid repeated arithmetic |
| pvaibhav | 35:fb6e4601adf3 | 113 | _2q0 = 2.0 * q0; |
| pvaibhav | 35:fb6e4601adf3 | 114 | _2q1 = 2.0 * q1; |
| pvaibhav | 35:fb6e4601adf3 | 115 | _2q2 = 2.0 * q2; |
| pvaibhav | 35:fb6e4601adf3 | 116 | _2q3 = 2.0 * q3; |
| pvaibhav | 35:fb6e4601adf3 | 117 | _4q0 = 4.0 * q0; |
| pvaibhav | 35:fb6e4601adf3 | 118 | _4q1 = 4.0 * q1; |
| pvaibhav | 35:fb6e4601adf3 | 119 | _4q2 = 4.0 * q2; |
| pvaibhav | 35:fb6e4601adf3 | 120 | _8q1 = 8.0 * q1; |
| pvaibhav | 35:fb6e4601adf3 | 121 | _8q2 = 8.0 * q2; |
| pvaibhav | 35:fb6e4601adf3 | 122 | q0q0 = q0 * q0; |
| pvaibhav | 35:fb6e4601adf3 | 123 | q1q1 = q1 * q1; |
| pvaibhav | 35:fb6e4601adf3 | 124 | q2q2 = q2 * q2; |
| pvaibhav | 35:fb6e4601adf3 | 125 | q3q3 = q3 * q3; |
| pvaibhav | 35:fb6e4601adf3 | 126 | |
| pvaibhav | 35:fb6e4601adf3 | 127 | // Gradient decent algorithm corrective step |
| pvaibhav | 35:fb6e4601adf3 | 128 | s0 = _4q0 * q2q2 + _2q2 * ax + _4q0 * q1q1 - _2q1 * ay; |
| pvaibhav | 35:fb6e4601adf3 | 129 | s1 = _4q1 * q3q3 - _2q3 * ax + 4.0 * q0q0 * q1 - _2q0 * ay - _4q1 + _8q1 * q1q1 + _8q1 * q2q2 + _4q1 * az; |
| pvaibhav | 35:fb6e4601adf3 | 130 | s2 = 4.0 * q0q0 * q2 + _2q0 * ax + _4q2 * q3q3 - _2q3 * ay - _4q2 + _8q2 * q1q1 + _8q2 * q2q2 + _4q2 * az; |
| pvaibhav | 35:fb6e4601adf3 | 131 | s3 = 4.0 * q1q1 * q3 - _2q1 * ax + 4.0 * q2q2 * q3 - _2q2 * ay; |
| pvaibhav | 35:fb6e4601adf3 | 132 | recipNorm = 1.0 / sqrt(s0 * s0 + s1 * s1 + s2 * s2 + s3 * s3); // normalise step magnitude |
| pvaibhav | 35:fb6e4601adf3 | 133 | s0 *= recipNorm; |
| pvaibhav | 35:fb6e4601adf3 | 134 | s1 *= recipNorm; |
| pvaibhav | 35:fb6e4601adf3 | 135 | s2 *= recipNorm; |
| pvaibhav | 35:fb6e4601adf3 | 136 | s3 *= recipNorm; |
| pvaibhav | 35:fb6e4601adf3 | 137 | |
| pvaibhav | 35:fb6e4601adf3 | 138 | // Apply feedback step |
| pvaibhav | 35:fb6e4601adf3 | 139 | qDot1 -= beta * s0; |
| pvaibhav | 35:fb6e4601adf3 | 140 | qDot2 -= beta * s1; |
| pvaibhav | 35:fb6e4601adf3 | 141 | qDot3 -= beta * s2; |
| pvaibhav | 35:fb6e4601adf3 | 142 | qDot4 -= beta * s3; |
| pvaibhav | 35:fb6e4601adf3 | 143 | } |
| pvaibhav | 35:fb6e4601adf3 | 144 | |
| pvaibhav | 35:fb6e4601adf3 | 145 | // Integrate rate of change of quaternion to yield quaternion |
| pvaibhav | 35:fb6e4601adf3 | 146 | q0 += qDot1 * deltat; |
| pvaibhav | 35:fb6e4601adf3 | 147 | q1 += qDot2 * deltat; |
| pvaibhav | 35:fb6e4601adf3 | 148 | q2 += qDot3 * deltat; |
| pvaibhav | 35:fb6e4601adf3 | 149 | q3 += qDot4 * deltat; |
| pvaibhav | 35:fb6e4601adf3 | 150 | |
| pvaibhav | 35:fb6e4601adf3 | 151 | // Normalise quaternion |
| pvaibhav | 35:fb6e4601adf3 | 152 | recipNorm = 1.0 / sqrt(q0 * q0 + q1 * q1 + q2 * q2 + q3 * q3); |
| pvaibhav | 35:fb6e4601adf3 | 153 | q0 *= recipNorm; |
| pvaibhav | 35:fb6e4601adf3 | 154 | q1 *= recipNorm; |
| pvaibhav | 35:fb6e4601adf3 | 155 | q2 *= recipNorm; |
| pvaibhav | 35:fb6e4601adf3 | 156 | q3 *= recipNorm; |
| pvaibhav | 35:fb6e4601adf3 | 157 | |
| pvaibhav | 35:fb6e4601adf3 | 158 | // return |
| pvaibhav | 35:fb6e4601adf3 | 159 | q.w = q0; |
| pvaibhav | 35:fb6e4601adf3 | 160 | q.v.x = q1; |
| pvaibhav | 35:fb6e4601adf3 | 161 | q.v.y = q2; |
| pvaibhav | 35:fb6e4601adf3 | 162 | q.v.z = q3; |
| pvaibhav | 35:fb6e4601adf3 | 163 | } |
| pvaibhav | 35:fb6e4601adf3 | 164 | |
| pvaibhav | 15:4488660e1a3b | 165 | void SensorFusion::updateFilter(float ax, float ay, float az, float gx, float gy, float gz, float mx, float my, float mz) |
| pvaibhav | 15:4488660e1a3b | 166 | { |
| pvaibhav | 15:4488660e1a3b | 167 | float q1 = q.w, q2 = q.v.x, q3 = q.v.y, q4 = q.v.z; // short name local variable for readability |
| pvaibhav | 15:4488660e1a3b | 168 | float norm; |
| pvaibhav | 15:4488660e1a3b | 169 | float s1, s2, s3, s4; |
| pvaibhav | 15:4488660e1a3b | 170 | |
| pvaibhav | 15:4488660e1a3b | 171 | // Auxiliary variables to avoid repeated arithmetic |
| pvaibhav | 15:4488660e1a3b | 172 | const float _2q1 = 2.0f * q1; |
| pvaibhav | 15:4488660e1a3b | 173 | const float _2q2 = 2.0f * q2; |
| pvaibhav | 15:4488660e1a3b | 174 | const float _2q3 = 2.0f * q3; |
| pvaibhav | 15:4488660e1a3b | 175 | const float _2q4 = 2.0f * q4; |
| pvaibhav | 15:4488660e1a3b | 176 | const float _2q1q3 = 2.0f * q1 * q3; |
| pvaibhav | 15:4488660e1a3b | 177 | const float _2q3q4 = 2.0f * q3 * q4; |
| pvaibhav | 15:4488660e1a3b | 178 | const float q1q1 = q1 * q1; |
| pvaibhav | 15:4488660e1a3b | 179 | const float q1q2 = q1 * q2; |
| pvaibhav | 15:4488660e1a3b | 180 | const float q1q3 = q1 * q3; |
| pvaibhav | 15:4488660e1a3b | 181 | const float q1q4 = q1 * q4; |
| pvaibhav | 15:4488660e1a3b | 182 | const float q2q2 = q2 * q2; |
| pvaibhav | 15:4488660e1a3b | 183 | const float q2q3 = q2 * q3; |
| pvaibhav | 15:4488660e1a3b | 184 | const float q2q4 = q2 * q4; |
| pvaibhav | 15:4488660e1a3b | 185 | const float q3q3 = q3 * q3; |
| pvaibhav | 15:4488660e1a3b | 186 | const float q3q4 = q3 * q4; |
| pvaibhav | 15:4488660e1a3b | 187 | const float q4q4 = q4 * q4; |
| pvaibhav | 15:4488660e1a3b | 188 | |
| pvaibhav | 15:4488660e1a3b | 189 | // Normalise accelerometer measurement |
| pvaibhav | 15:4488660e1a3b | 190 | norm = sqrt(ax * ax + ay * ay + az * az); |
| pvaibhav | 15:4488660e1a3b | 191 | if (norm == 0.0f) return; // handle NaN |
| pvaibhav | 15:4488660e1a3b | 192 | norm = 1.0f/norm; |
| pvaibhav | 15:4488660e1a3b | 193 | ax *= norm; |
| pvaibhav | 15:4488660e1a3b | 194 | ay *= norm; |
| pvaibhav | 15:4488660e1a3b | 195 | az *= norm; |
| pvaibhav | 15:4488660e1a3b | 196 | |
| pvaibhav | 15:4488660e1a3b | 197 | // Normalise magnetometer measurement |
| pvaibhav | 15:4488660e1a3b | 198 | norm = sqrt(mx * mx + my * my + mz * mz); |
| pvaibhav | 15:4488660e1a3b | 199 | if (norm == 0.0f) return; // handle NaN |
| pvaibhav | 15:4488660e1a3b | 200 | norm = 1.0f/norm; |
| pvaibhav | 15:4488660e1a3b | 201 | mx *= norm; |
| pvaibhav | 15:4488660e1a3b | 202 | my *= norm; |
| pvaibhav | 15:4488660e1a3b | 203 | mz *= norm; |
| pvaibhav | 15:4488660e1a3b | 204 | |
| pvaibhav | 15:4488660e1a3b | 205 | // Reference direction of Earth's magnetic field |
| pvaibhav | 15:4488660e1a3b | 206 | const float _2q1mx = 2.0f * q1 * mx; |
| pvaibhav | 15:4488660e1a3b | 207 | const float _2q1my = 2.0f * q1 * my; |
| pvaibhav | 15:4488660e1a3b | 208 | const float _2q1mz = 2.0f * q1 * mz; |
| pvaibhav | 15:4488660e1a3b | 209 | const float _2q2mx = 2.0f * q2 * mx; |
| pvaibhav | 15:4488660e1a3b | 210 | const float hx = mx * q1q1 - _2q1my * q4 + _2q1mz * q3 + mx * q2q2 + _2q2 * my * q3 + _2q2 * mz * q4 - mx * q3q3 - mx * q4q4; |
| pvaibhav | 15:4488660e1a3b | 211 | const float hy = _2q1mx * q4 + my * q1q1 - _2q1mz * q2 + _2q2mx * q3 - my * q2q2 + my * q3q3 + _2q3 * mz * q4 - my * q4q4; |
| pvaibhav | 15:4488660e1a3b | 212 | const float _2bx = sqrt(hx * hx + hy * hy); |
| pvaibhav | 15:4488660e1a3b | 213 | const float _2bz = -_2q1mx * q3 + _2q1my * q2 + mz * q1q1 + _2q2mx * q4 - mz * q2q2 + _2q3 * my * q4 - mz * q3q3 + mz * q4q4; |
| pvaibhav | 15:4488660e1a3b | 214 | const float _4bx = 2.0f * _2bx; |
| pvaibhav | 15:4488660e1a3b | 215 | const float _4bz = 2.0f * _2bz; |
| pvaibhav | 15:4488660e1a3b | 216 | |
| pvaibhav | 15:4488660e1a3b | 217 | // Gradient decent algorithm corrective step |
| pvaibhav | 15:4488660e1a3b | 218 | s1 = -_2q3 * (2.0f * q2q4 - _2q1q3 - ax) + _2q2 * (2.0f * q1q2 + _2q3q4 - ay) - _2bz * q3 * (_2bx * (0.5f - q3q3 - q4q4) + _2bz * (q2q4 - q1q3) - mx) + (-_2bx * q4 + _2bz * q2) * (_2bx * (q2q3 - q1q4) + _2bz * (q1q2 + q3q4) - my) + _2bx * q3 * (_2bx * (q1q3 + q2q4) + _2bz * (0.5f - q2q2 - q3q3) - mz); |
| pvaibhav | 15:4488660e1a3b | 219 | s2 = _2q4 * (2.0f * q2q4 - _2q1q3 - ax) + _2q1 * (2.0f * q1q2 + _2q3q4 - ay) - 4.0f * q2 * (1.0f - 2.0f * q2q2 - 2.0f * q3q3 - az) + _2bz * q4 * (_2bx * (0.5f - q3q3 - q4q4) + _2bz * (q2q4 - q1q3) - mx) + (_2bx * q3 + _2bz * q1) * (_2bx * (q2q3 - q1q4) + _2bz * (q1q2 + q3q4) - my) + (_2bx * q4 - _4bz * q2) * (_2bx * (q1q3 + q2q4) + _2bz * (0.5f - q2q2 - q3q3) - mz); |
| pvaibhav | 15:4488660e1a3b | 220 | s3 = -_2q1 * (2.0f * q2q4 - _2q1q3 - ax) + _2q4 * (2.0f * q1q2 + _2q3q4 - ay) - 4.0f * q3 * (1.0f - 2.0f * q2q2 - 2.0f * q3q3 - az) + (-_4bx * q3 - _2bz * q1) * (_2bx * (0.5f - q3q3 - q4q4) + _2bz * (q2q4 - q1q3) - mx) + (_2bx * q2 + _2bz * q4) * (_2bx * (q2q3 - q1q4) + _2bz * (q1q2 + q3q4) - my) + (_2bx * q1 - _4bz * q3) * (_2bx * (q1q3 + q2q4) + _2bz * (0.5f - q2q2 - q3q3) - mz); |
| pvaibhav | 15:4488660e1a3b | 221 | s4 = _2q2 * (2.0f * q2q4 - _2q1q3 - ax) + _2q3 * (2.0f * q1q2 + _2q3q4 - ay) + (-_4bx * q4 + _2bz * q2) * (_2bx * (0.5f - q3q3 - q4q4) + _2bz * (q2q4 - q1q3) - mx) + (-_2bx * q1 + _2bz * q3) * (_2bx * (q2q3 - q1q4) + _2bz * (q1q2 + q3q4) - my) + _2bx * q2 * (_2bx * (q1q3 + q2q4) + _2bz * (0.5f - q2q2 - q3q3) - mz); |
| pvaibhav | 15:4488660e1a3b | 222 | norm = sqrt(s1 * s1 + s2 * s2 + s3 * s3 + s4 * s4); // normalise step magnitude |
| pvaibhav | 15:4488660e1a3b | 223 | norm = 1.0f/norm; |
| pvaibhav | 15:4488660e1a3b | 224 | s1 *= norm; |
| pvaibhav | 15:4488660e1a3b | 225 | s2 *= norm; |
| pvaibhav | 15:4488660e1a3b | 226 | s3 *= norm; |
| pvaibhav | 15:4488660e1a3b | 227 | s4 *= norm; |
| pvaibhav | 15:4488660e1a3b | 228 | |
| pvaibhav | 15:4488660e1a3b | 229 | // Compute rate of change of quaternion |
| pvaibhav | 15:4488660e1a3b | 230 | const float qDot1 = 0.5f * (-q2 * gx - q3 * gy - q4 * gz) - beta * s1; |
| pvaibhav | 15:4488660e1a3b | 231 | const float qDot2 = 0.5f * (q1 * gx + q3 * gz - q4 * gy) - beta * s2; |
| pvaibhav | 15:4488660e1a3b | 232 | const float qDot3 = 0.5f * (q1 * gy - q2 * gz + q4 * gx) - beta * s3; |
| pvaibhav | 15:4488660e1a3b | 233 | const float qDot4 = 0.5f * (q1 * gz + q2 * gy - q3 * gx) - beta * s4; |
| pvaibhav | 15:4488660e1a3b | 234 | |
| pvaibhav | 15:4488660e1a3b | 235 | // Integrate to yield quaternion |
| pvaibhav | 15:4488660e1a3b | 236 | q1 += qDot1 * deltat; |
| pvaibhav | 15:4488660e1a3b | 237 | q2 += qDot2 * deltat; |
| pvaibhav | 15:4488660e1a3b | 238 | q3 += qDot3 * deltat; |
| pvaibhav | 15:4488660e1a3b | 239 | q4 += qDot4 * deltat; |
| pvaibhav | 15:4488660e1a3b | 240 | norm = sqrt(q1 * q1 + q2 * q2 + q3 * q3 + q4 * q4); // normalise quaternion |
| pvaibhav | 15:4488660e1a3b | 241 | norm = 1.0f/norm; |
| pvaibhav | 15:4488660e1a3b | 242 | q.w = q1 * norm; |
| pvaibhav | 15:4488660e1a3b | 243 | q.v.x = q2 * norm; |
| pvaibhav | 15:4488660e1a3b | 244 | q.v.y = q3 * norm; |
| pvaibhav | 15:4488660e1a3b | 245 | q.v.z = q4 * norm; |
| pvaibhav | 15:4488660e1a3b | 246 | } |