Luca Olivieri / Mbed 2 deprecated LSM9DS0_mbed

This is a port from the library for Arduino provided by Sparkfun with their breakout board of the LSM9DS0. The original library can be found here: https://github.com/sparkfun/SparkFun_LSM9DS0_Arduino_Library/tree/V_1.0.1 It is also provided an AHRS example based on Madgwick, also a port from an Arduino example. All of this was tested on a Nucleo F411RE and a Sparkfun breakout board.

Dependencies:   mbed

AHRS_example.cpp@0:32b177f0030e, 2015-12-05 (annotated)

Committer:
olimexsmart
Date:
Sat Dec 05 16:23:36 2015 +0000
Revision:
0:32b177f0030e
What in this world I am supposed to type here?

Who changed what in which revision?

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olimexsmart 0:32b177f0030e 1 #include "LSM9DS0_mbed.h"
olimexsmart 0:32b177f0030e 2 #include "mbed.h"
olimexsmart 0:32b177f0030e 3
olimexsmart 0:32b177f0030e 4 #define INT1 PB_3
olimexsmart 0:32b177f0030e 5 #define INT2 PA_10
olimexsmart 0:32b177f0030e 6 #define DR_DYG PB_5
olimexsmart 0:32b177f0030e 7
olimexsmart 0:32b177f0030e 8 #define SDA PB_9
olimexsmart 0:32b177f0030e 9 #define SCL PB_8
olimexsmart 0:32b177f0030e 10
olimexsmart 0:32b177f0030e 11 ///////////////////////
olimexsmart 0:32b177f0030e 12 // Example I2C Setup //
olimexsmart 0:32b177f0030e 13 ///////////////////////
olimexsmart 0:32b177f0030e 14 // SDO_XM and SDO_G are both grounded, so our addresses are:
olimexsmart 0:32b177f0030e 15 #define LSM9DS0_XM 0x1D // Would be 0x1E if SDO_XM is LOW
olimexsmart 0:32b177f0030e 16 #define LSM9DS0_G 0x6B // Would be 0x6A if SDO_G is LOW
olimexsmart 0:32b177f0030e 17
olimexsmart 0:32b177f0030e 18 // Create an instance of the LSM9DS0 library called `dof` the
olimexsmart 0:32b177f0030e 19 // parameters for this constructor are:
olimexsmart 0:32b177f0030e 20 // [I2C SDA], [I2C SCL],[gyro I2C address],[xm I2C add.]
olimexsmart 0:32b177f0030e 21 LSM9DS0 dof(SDA, SCL, LSM9DS0_G, LSM9DS0_XM);
olimexsmart 0:32b177f0030e 22
olimexsmart 0:32b177f0030e 23 ///////////////////////////////////
olimexsmart 0:32b177f0030e 24 // Interrupt Handler Definitions //
olimexsmart 0:32b177f0030e 25 ///////////////////////////////////
olimexsmart 0:32b177f0030e 26 DigitalIn INT1XM(INT1);
olimexsmart 0:32b177f0030e 27 DigitalIn INT2XM(INT2);
olimexsmart 0:32b177f0030e 28 DigitalIn DRDYG(DR_DYG);
olimexsmart 0:32b177f0030e 29
olimexsmart 0:32b177f0030e 30 // global constants for 9 DoF fusion and AHRS (Attitude and Heading Reference System)
olimexsmart 0:32b177f0030e 31 #define GyroMeasError PI * (40.0f / 180.0f) // gyroscope measurement error in rads/s (shown as 3 deg/s)
olimexsmart 0:32b177f0030e 32 #define GyroMeasDrift PI * (0.0f / 180.0f) // gyroscope measurement drift in rad/s/s (shown as 0.0 deg/s/s)
olimexsmart 0:32b177f0030e 33 // There is a tradeoff in the beta parameter between accuracy and response speed.
olimexsmart 0:32b177f0030e 34 // In the original Madgwick study, beta of 0.041 (corresponding to GyroMeasError of 2.7 degrees/s) was found to give optimal accuracy.
olimexsmart 0:32b177f0030e 35 // However, with this value, the LSM9SD0 response time is about 10 seconds to a stable initial quaternion.
olimexsmart 0:32b177f0030e 36 // Subsequent changes also require a longish lag time to a stable output, not fast enough for a quadcopter or robot car!
olimexsmart 0:32b177f0030e 37 // By increasing beta (GyroMeasError) by about a factor of fifteen, the response time constant is reduced to ~2 sec
olimexsmart 0:32b177f0030e 38 // I haven't noticed any reduction in solution accuracy. This is essentially the I coefficient in a PID control sense;
olimexsmart 0:32b177f0030e 39 // the bigger the feedback coefficient, the faster the solution converges, usually at the expense of accuracy.
olimexsmart 0:32b177f0030e 40 // In any case, this is the free parameter in the Madgwick filtering and fusion scheme.
olimexsmart 0:32b177f0030e 41 #define beta sqrt(3.0f / 4.0f) * GyroMeasError // compute beta
olimexsmart 0:32b177f0030e 42 #define zeta sqrt(3.0f / 4.0f) * GyroMeasDrift // compute zeta, the other free parameter in the Madgwick scheme usually set to a small or zero value
olimexsmart 0:32b177f0030e 43 #define Kp 2.0f * 5.0f // these are the free parameters in the Mahony filter and fusion scheme, Kp for proportional feedback, Ki for integral
olimexsmart 0:32b177f0030e 44 #define Ki 0.0f
olimexsmart 0:32b177f0030e 45 const float PI = 3.14159265358979f;
olimexsmart 0:32b177f0030e 46
olimexsmart 0:32b177f0030e 47 Timer t1; //Integration timer
olimexsmart 0:32b177f0030e 48 Timer t2; //Print timer
olimexsmart 0:32b177f0030e 49 Serial pc(SERIAL_TX, SERIAL_RX);
olimexsmart 0:32b177f0030e 50 DigitalOut myled(LED1);
olimexsmart 0:32b177f0030e 51 float pitch, yaw, roll, heading;
olimexsmart 0:32b177f0030e 52 float deltat = 0.0f; // integration interval for both filter schemes
olimexsmart 0:32b177f0030e 53
olimexsmart 0:32b177f0030e 54
olimexsmart 0:32b177f0030e 55 float abias[3] = {0, 0, 0}, gbias[3] = {0, 0, 0};
olimexsmart 0:32b177f0030e 56 float ax, ay, az, gx, gy, gz, mx, my, mz; // variables to hold latest sensor data values
olimexsmart 0:32b177f0030e 57 float q[4] = {1.0f, 0.0f, 0.0f, 0.0f}; // vector to hold quaternion
olimexsmart 0:32b177f0030e 58 float eInt[3] = {0.0f, 0.0f, 0.0f}; // vector to hold integral error for Mahony method
olimexsmart 0:32b177f0030e 59 float temperature;
olimexsmart 0:32b177f0030e 60
olimexsmart 0:32b177f0030e 61 //////////////////////////////////
olimexsmart 0:32b177f0030e 62 // FUNCTION DECLARATION //
olimexsmart 0:32b177f0030e 63 //////////////////////////////////
olimexsmart 0:32b177f0030e 64 void setup();
olimexsmart 0:32b177f0030e 65 void loop();
olimexsmart 0:32b177f0030e 66 void MadgwickQuaternionUpdate(float ax, float ay, float az, float gx, float gy, float gz, float mx, float my, float mz);
olimexsmart 0:32b177f0030e 67 void MahonyQuaternionUpdate(float ax, float ay, float az, float gx, float gy, float gz, float mx, float my, float mz);
olimexsmart 0:32b177f0030e 68 void dataGyro();
olimexsmart 0:32b177f0030e 69 void dataAccel();
olimexsmart 0:32b177f0030e 70 void dataMag();
olimexsmart 0:32b177f0030e 71
olimexsmart 0:32b177f0030e 72 //////////////////////////////////
olimexsmart 0:32b177f0030e 73 // MAIN //
olimexsmart 0:32b177f0030e 74 //////////////////////////////////
olimexsmart 0:32b177f0030e 75 int main()
olimexsmart 0:32b177f0030e 76 {
olimexsmart 0:32b177f0030e 77 setup(); //Setup sensor and Serial
olimexsmart 0:32b177f0030e 78 pc.printf("Setup Done\n\r");
olimexsmart 0:32b177f0030e 79
olimexsmart 0:32b177f0030e 80
olimexsmart 0:32b177f0030e 81 while (true)
olimexsmart 0:32b177f0030e 82 loop();
olimexsmart 0:32b177f0030e 83 }
olimexsmart 0:32b177f0030e 84
olimexsmart 0:32b177f0030e 85
olimexsmart 0:32b177f0030e 86 //////////////////////////////////
olimexsmart 0:32b177f0030e 87 // FUNCTION BODY //
olimexsmart 0:32b177f0030e 88 //////////////////////////////////
olimexsmart 0:32b177f0030e 89 void dataGyro()
olimexsmart 0:32b177f0030e 90 {
olimexsmart 0:32b177f0030e 91 dof.readGyro(); // Read raw gyro data
olimexsmart 0:32b177f0030e 92 gx = dof.calcGyro(dof.gx) - gbias[0]; // Convert to degrees per seconds, remove gyro biases
olimexsmart 0:32b177f0030e 93 gy = dof.calcGyro(dof.gy) - gbias[1];
olimexsmart 0:32b177f0030e 94 gz = dof.calcGyro(dof.gz) - gbias[2];
olimexsmart 0:32b177f0030e 95 }
olimexsmart 0:32b177f0030e 96 void dataAccel()
olimexsmart 0:32b177f0030e 97 {
olimexsmart 0:32b177f0030e 98 dof.readAccel(); // Read raw accelerometer data
olimexsmart 0:32b177f0030e 99 ax = dof.calcAccel(dof.ax) - abias[0]; // Convert to g's, remove accelerometer biases
olimexsmart 0:32b177f0030e 100 ay = dof.calcAccel(dof.ay) - abias[1];
olimexsmart 0:32b177f0030e 101 az = dof.calcAccel(dof.az) - abias[2];
olimexsmart 0:32b177f0030e 102 }
olimexsmart 0:32b177f0030e 103 void dataMag()
olimexsmart 0:32b177f0030e 104 {
olimexsmart 0:32b177f0030e 105 dof.readMag(); // Read raw magnetometer data
olimexsmart 0:32b177f0030e 106 mx = dof.calcMag(dof.mx); // Convert to Gauss and correct for calibration
olimexsmart 0:32b177f0030e 107 my = dof.calcMag(dof.my);
olimexsmart 0:32b177f0030e 108 mz = dof.calcMag(dof.mz);
olimexsmart 0:32b177f0030e 109 }
olimexsmart 0:32b177f0030e 110 void setup()
olimexsmart 0:32b177f0030e 111 {
olimexsmart 0:32b177f0030e 112 pc.baud(115200); // Start serial at 115200 bps
olimexsmart 0:32b177f0030e 113 myled = true;
olimexsmart 0:32b177f0030e 114 /*//Interrupt
olimexsmart 0:32b177f0030e 115 INT1XM.rise(&dataAccel);
olimexsmart 0:32b177f0030e 116 INT2XM.rise(&dataMag);
olimexsmart 0:32b177f0030e 117 DRDYG.rise(&dataGyro);
olimexsmart 0:32b177f0030e 118 */
olimexsmart 0:32b177f0030e 119 // begin() returns a 16-bit value which includes both the gyro
olimexsmart 0:32b177f0030e 120 // and accelerometers WHO_AM_I response. You can check this to
olimexsmart 0:32b177f0030e 121 // make sure communication was successful.
olimexsmart 0:32b177f0030e 122 uint16_t status = dof.begin();
olimexsmart 0:32b177f0030e 123
olimexsmart 0:32b177f0030e 124 pc.printf("LSM9DS0 WHO_AM_I's returned: ");
olimexsmart 0:32b177f0030e 125 pc.printf("0x%X\t", status);
olimexsmart 0:32b177f0030e 126 pc.printf("Should be 0x49D4");
olimexsmart 0:32b177f0030e 127 pc.printf("\n\r");
olimexsmart 0:32b177f0030e 128
olimexsmart 0:32b177f0030e 129
olimexsmart 0:32b177f0030e 130 // Set data output ranges; choose lowest ranges for maximum resolution
olimexsmart 0:32b177f0030e 131 // Accelerometer scale can be: A_SCALE_2G, A_SCALE_4G, A_SCALE_6G, A_SCALE_8G, or A_SCALE_16G
olimexsmart 0:32b177f0030e 132 dof.setAccelScale(dof.A_SCALE_2G);
olimexsmart 0:32b177f0030e 133 // Gyro scale can be: G_SCALE__245, G_SCALE__500, or G_SCALE__2000DPS
olimexsmart 0:32b177f0030e 134 dof.setGyroScale(dof.G_SCALE_245DPS);
olimexsmart 0:32b177f0030e 135 // Magnetometer scale can be: M_SCALE_2GS, M_SCALE_4GS, M_SCALE_8GS, M_SCALE_12GS
olimexsmart 0:32b177f0030e 136 dof.setMagScale(dof.M_SCALE_2GS);
olimexsmart 0:32b177f0030e 137
olimexsmart 0:32b177f0030e 138 // Set output data rates
olimexsmart 0:32b177f0030e 139 // Accelerometer output data rate (ODR) can be: A_ODR_3125 (3.225 Hz), A_ODR_625 (6.25 Hz), A_ODR_125 (12.5 Hz), A_ODR_25, A_ODR_50,
olimexsmart 0:32b177f0030e 140 // A_ODR_100, A_ODR_200, A_ODR_400, A_ODR_800, A_ODR_1600 (1600 Hz)
olimexsmart 0:32b177f0030e 141 dof.setAccelODR(dof.A_ODR_200); // Set accelerometer update rate at 100 Hz
olimexsmart 0:32b177f0030e 142 // Accelerometer anti-aliasing filter rate can be 50, 194, 362, or 763 Hz
olimexsmart 0:32b177f0030e 143 // Anti-aliasing acts like a low-pass filter allowing oversampling of accelerometer and rejection of high-frequency spurious noise.
olimexsmart 0:32b177f0030e 144 // Strategy here is to effectively oversample accelerometer at 100 Hz and use a 50 Hz anti-aliasing (low-pass) filter frequency
olimexsmart 0:32b177f0030e 145 // to get a smooth ~150 Hz filter update rate
olimexsmart 0:32b177f0030e 146 dof.setAccelABW(dof.A_ABW_50); // Choose lowest filter setting for low noise
olimexsmart 0:32b177f0030e 147
olimexsmart 0:32b177f0030e 148 // Gyro output data rates can be: 95 Hz (bandwidth 12.5 or 25 Hz), 190 Hz (bandwidth 12.5, 25, 50, or 70 Hz)
olimexsmart 0:32b177f0030e 149 // 380 Hz (bandwidth 20, 25, 50, 100 Hz), or 760 Hz (bandwidth 30, 35, 50, 100 Hz)
olimexsmart 0:32b177f0030e 150 dof.setGyroODR(dof.G_ODR_190_BW_125); // Set gyro update rate to 190 Hz with the smallest bandwidth for low noise
olimexsmart 0:32b177f0030e 151
olimexsmart 0:32b177f0030e 152 // Magnetometer output data rate can be: 3.125 (ODR_3125), 6.25 (ODR_625), 12.5 (ODR_125), 25, 50, or 100 Hz
olimexsmart 0:32b177f0030e 153 dof.setMagODR(dof.M_ODR_125); // Set magnetometer to update every 80 ms
olimexsmart 0:32b177f0030e 154
olimexsmart 0:32b177f0030e 155 // Use the FIFO mode to average accelerometer and gyro readings to calculate the biases, which can then be removed from
olimexsmart 0:32b177f0030e 156 // all subsequent measurements.
olimexsmart 0:32b177f0030e 157 dof.calLSM9DS0(gbias, abias);
olimexsmart 0:32b177f0030e 158
olimexsmart 0:32b177f0030e 159 // Start timers to get integration time and print time
olimexsmart 0:32b177f0030e 160 t2.start();
olimexsmart 0:32b177f0030e 161 t1.start();
olimexsmart 0:32b177f0030e 162 dataGyro();
olimexsmart 0:32b177f0030e 163 dataAccel();
olimexsmart 0:32b177f0030e 164 dataMag();
olimexsmart 0:32b177f0030e 165 }
olimexsmart 0:32b177f0030e 166
olimexsmart 0:32b177f0030e 167 void loop()
olimexsmart 0:32b177f0030e 168 {
olimexsmart 0:32b177f0030e 169 //Couldn't manage to get these in interrupt, the interrupt won't fire. It isn't so nececesary indeed.
olimexsmart 0:32b177f0030e 170 if(INT1XM.read())
olimexsmart 0:32b177f0030e 171 dataAccel();
olimexsmart 0:32b177f0030e 172 if(INT2XM.read())
olimexsmart 0:32b177f0030e 173 {
olimexsmart 0:32b177f0030e 174 dataMag();
olimexsmart 0:32b177f0030e 175 // dof.readTemp(); Can't get temp reading from a Sparkfun breakout board, the problem is not just mine.
olimexsmart 0:32b177f0030e 176 //temperature = 21.0 + (float) dof.temperature/8.0f; // slope is 8 LSB per degree C, just guessing at the intercept
olimexsmart 0:32b177f0030e 177 }
olimexsmart 0:32b177f0030e 178 if(DRDYG.read())
olimexsmart 0:32b177f0030e 179 dataGyro();
olimexsmart 0:32b177f0030e 180
olimexsmart 0:32b177f0030e 181 deltat = t1.read(); // set integration time by time elapsed since last filter update
olimexsmart 0:32b177f0030e 182 t1.reset();
olimexsmart 0:32b177f0030e 183
olimexsmart 0:32b177f0030e 184 // Sensors x- and y-axes are aligned but magnetometer z-axis (+ down) is opposite to z-axis (+ up) of accelerometer and gyro!
olimexsmart 0:32b177f0030e 185 // This is ok by aircraft orientation standards!
olimexsmart 0:32b177f0030e 186 // Pass gyro rate as rad/s
olimexsmart 0:32b177f0030e 187 MadgwickQuaternionUpdate(ax, ay, az, gx*PI/180.0f, gy*PI/180.0f, gz*PI/180.0f, mx, my, mz);
olimexsmart 0:32b177f0030e 188 //MahonyQuaternionUpdate(ax, ay, az, gx*PI/180.0f, gy*PI/180.0f, gz*PI/180.0f, mx, my, mz);
olimexsmart 0:32b177f0030e 189
olimexsmart 0:32b177f0030e 190
olimexsmart 0:32b177f0030e 191 // Serial print at 0.5 s rate independent of data rates
olimexsmart 0:32b177f0030e 192 if (t2.read() > 1.0f) {
olimexsmart 0:32b177f0030e 193 t2.reset();
olimexsmart 0:32b177f0030e 194
olimexsmart 0:32b177f0030e 195 myled = !myled;
olimexsmart 0:32b177f0030e 196
olimexsmart 0:32b177f0030e 197 pc.printf("%f\t%f\t%f\n\r", ax, ay, az);
olimexsmart 0:32b177f0030e 198 pc.printf("%f\t%f\t%f\n\r", gx, gy, gz);
olimexsmart 0:32b177f0030e 199 pc.printf("%f\t%f\t%f\n\r", mx, my, mz);
olimexsmart 0:32b177f0030e 200 /*
olimexsmart 0:32b177f0030e 201 // Define output variables from updated quaternion---these are Tait-Bryan angles, commonly used in aircraft orientation.
olimexsmart 0:32b177f0030e 202 // In this coordinate system, the positive z-axis is down toward Earth.
olimexsmart 0:32b177f0030e 203 // Yaw is the angle between Sensor x-axis and Earth magnetic North (or true North if corrected for local declination),
olimexsmart 0:32b177f0030e 204 // looking down on the sensor positive yaw is counterclockwise.
olimexsmart 0:32b177f0030e 205 // Pitch is angle between sensor x-axis and Earth ground plane, toward the Earth is positive, up toward the sky is negative.
olimexsmart 0:32b177f0030e 206 // Roll is angle between sensor y-axis and Earth ground plane, y-axis up is positive roll.
olimexsmart 0:32b177f0030e 207 // These arise from the definition of the homogeneous rotation matrix constructed from quaternions.
olimexsmart 0:32b177f0030e 208 // Tait-Bryan angles as well as Euler angles are non-commutative; that is, to get the correct orientation the rotations must be
olimexsmart 0:32b177f0030e 209 // applied in the correct order which for this configuration is yaw, pitch, and then roll.
olimexsmart 0:32b177f0030e 210 // For more see http://en.wikipedia.org/wiki/Conversion_between_quaternions_and_Euler_angles which has additional links.
olimexsmart 0:32b177f0030e 211 */
olimexsmart 0:32b177f0030e 212 yaw = atan2(2.0f * (q[1] * q[2] + q[0] * q[3]), q[0] * q[0] + q[1] * q[1] - q[2] * q[2] - q[3] * q[3]);
olimexsmart 0:32b177f0030e 213 pitch = -asin(2.0f * (q[1] * q[3] - q[0] * q[2]));
olimexsmart 0:32b177f0030e 214 roll = atan2(2.0f * (q[0] * q[1] + q[2] * q[3]), q[0] * q[0] - q[1] * q[1] - q[2] * q[2] + q[3] * q[3]);
olimexsmart 0:32b177f0030e 215 pitch *= 180.0f / PI;
olimexsmart 0:32b177f0030e 216 yaw *= 180.0f / PI;
olimexsmart 0:32b177f0030e 217 roll *= 180.0f / PI;
olimexsmart 0:32b177f0030e 218 //yaw -= 13.8; // Declination at Danville, California is 13 degrees 48 minutes and 47 seconds on 2014-04-04
olimexsmart 0:32b177f0030e 219
olimexsmart 0:32b177f0030e 220 /*
olimexsmart 0:32b177f0030e 221 pc.printf("Temperature = ");
olimexsmart 0:32b177f0030e 222 pc.printf("%d\n\r", dof.temperature);
olimexsmart 0:32b177f0030e 223 */
olimexsmart 0:32b177f0030e 224 //Angles print
olimexsmart 0:32b177f0030e 225 pc.printf("Yaw, Pitch, Roll: ");
olimexsmart 0:32b177f0030e 226 pc.printf("%f", yaw);
olimexsmart 0:32b177f0030e 227 pc.printf(", ");
olimexsmart 0:32b177f0030e 228 pc.printf("%f", pitch);
olimexsmart 0:32b177f0030e 229 pc.printf(", ");
olimexsmart 0:32b177f0030e 230 pc.printf("%f\n\r", roll);
olimexsmart 0:32b177f0030e 231
olimexsmart 0:32b177f0030e 232 //Update rate print
olimexsmart 0:32b177f0030e 233 pc.printf("Filter rate = ");
olimexsmart 0:32b177f0030e 234 pc.printf("%f\n\r", 1.0f/deltat);
olimexsmart 0:32b177f0030e 235
olimexsmart 0:32b177f0030e 236 /*
olimexsmart 0:32b177f0030e 237 // The filter update rate can be increased by reducing the rate of data reading. The optimal implementation is
olimexsmart 0:32b177f0030e 238 // one which balances the competing rates so they are about the same; that is, the filter updates the sensor orientation
olimexsmart 0:32b177f0030e 239 // at about the same rate the data is changing. Of course, other implementations are possible. One might consider
olimexsmart 0:32b177f0030e 240 // updating the filter at twice the average new data rate to allow for finite filter convergence times.
olimexsmart 0:32b177f0030e 241 // The filter update rate is determined mostly by the mathematical steps in the respective algorithms,
olimexsmart 0:32b177f0030e 242 // the processor speed (8 MHz for the 3.3V Pro Mini), and the sensor ODRs, especially the magnetometer ODR:
olimexsmart 0:32b177f0030e 243 // smaller ODRs for the magnetometer produce the above rates, maximum magnetometer ODR of 100 Hz produces
olimexsmart 0:32b177f0030e 244 // filter update rates of ~110 and ~135 Hz for the Madgwick and Mahony schemes, respectively.
olimexsmart 0:32b177f0030e 245 // This is presumably because the magnetometer read takes longer than the gyro or accelerometer reads.
olimexsmart 0:32b177f0030e 246 // With low ODR settings of 100 Hz, 95 Hz, and 6.25 Hz for the accelerometer, gyro, and magnetometer, respectively,
olimexsmart 0:32b177f0030e 247 // the filter is updating at a ~150 Hz rate using the Madgwick scheme and ~200 Hz using the Mahony scheme.
olimexsmart 0:32b177f0030e 248 // These filter update rates should be fast enough to maintain accurate platform orientation for
olimexsmart 0:32b177f0030e 249 // stabilization control of a fast-moving robot or quadcopter. Compare to the update rate of 200 Hz
olimexsmart 0:32b177f0030e 250 // produced by the on-board Digital Motion Processor of Invensense's MPU6050 6 DoF and MPU9150 9DoF sensors.
olimexsmart 0:32b177f0030e 251 // The 3.3 V 8 MHz Pro Mini is doing pretty well!
olimexsmart 0:32b177f0030e 252 */
olimexsmart 0:32b177f0030e 253 }
olimexsmart 0:32b177f0030e 254 }
olimexsmart 0:32b177f0030e 255
olimexsmart 0:32b177f0030e 256
olimexsmart 0:32b177f0030e 257
olimexsmart 0:32b177f0030e 258
olimexsmart 0:32b177f0030e 259 // Implementation of Sebastian Madgwick's "...efficient orientation filter for... inertial/magnetic sensor arrays"
olimexsmart 0:32b177f0030e 260 // (see http://www.x-io.co.uk/category/open-source/ for examples and more details)
olimexsmart 0:32b177f0030e 261 // which fuses acceleration, rotation rate, and magnetic moments to produce a quaternion-based estimate of absolute
olimexsmart 0:32b177f0030e 262 // device orientation -- which can be converted to yaw, pitch, and roll. Useful for stabilizing quadcopters, etc.
olimexsmart 0:32b177f0030e 263 // The performance of the orientation filter is at least as good as conventional Kalman-based filtering algorithms
olimexsmart 0:32b177f0030e 264 // but is much less computationally intensive---it can be performed on a 3.3 V Pro Mini operating at 8 MHz!
olimexsmart 0:32b177f0030e 265 void MadgwickQuaternionUpdate(float ax, float ay, float az, float gx, float gy, float gz, float mx, float my, float mz)
olimexsmart 0:32b177f0030e 266 {
olimexsmart 0:32b177f0030e 267 float q1 = q[0], q2 = q[1], q3 = q[2], q4 = q[3]; // short name local variable for readability
olimexsmart 0:32b177f0030e 268 float norm;
olimexsmart 0:32b177f0030e 269 float hx, hy, _2bx, _2bz;
olimexsmart 0:32b177f0030e 270 float s1, s2, s3, s4;
olimexsmart 0:32b177f0030e 271 float qDot1, qDot2, qDot3, qDot4;
olimexsmart 0:32b177f0030e 272
olimexsmart 0:32b177f0030e 273 // Auxiliary variables to avoid repeated arithmetic
olimexsmart 0:32b177f0030e 274 float _2q1mx;
olimexsmart 0:32b177f0030e 275 float _2q1my;
olimexsmart 0:32b177f0030e 276 float _2q1mz;
olimexsmart 0:32b177f0030e 277 float _2q2mx;
olimexsmart 0:32b177f0030e 278 float _4bx;
olimexsmart 0:32b177f0030e 279 float _4bz;
olimexsmart 0:32b177f0030e 280 float _2q1 = 2.0f * q1;
olimexsmart 0:32b177f0030e 281 float _2q2 = 2.0f * q2;
olimexsmart 0:32b177f0030e 282 float _2q3 = 2.0f * q3;
olimexsmart 0:32b177f0030e 283 float _2q4 = 2.0f * q4;
olimexsmart 0:32b177f0030e 284 float _2q1q3 = 2.0f * q1 * q3;
olimexsmart 0:32b177f0030e 285 float _2q3q4 = 2.0f * q3 * q4;
olimexsmart 0:32b177f0030e 286 float q1q1 = q1 * q1;
olimexsmart 0:32b177f0030e 287 float q1q2 = q1 * q2;
olimexsmart 0:32b177f0030e 288 float q1q3 = q1 * q3;
olimexsmart 0:32b177f0030e 289 float q1q4 = q1 * q4;
olimexsmart 0:32b177f0030e 290 float q2q2 = q2 * q2;
olimexsmart 0:32b177f0030e 291 float q2q3 = q2 * q3;
olimexsmart 0:32b177f0030e 292 float q2q4 = q2 * q4;
olimexsmart 0:32b177f0030e 293 float q3q3 = q3 * q3;
olimexsmart 0:32b177f0030e 294 float q3q4 = q3 * q4;
olimexsmart 0:32b177f0030e 295 float q4q4 = q4 * q4;
olimexsmart 0:32b177f0030e 296
olimexsmart 0:32b177f0030e 297 // Normalise accelerometer measurement
olimexsmart 0:32b177f0030e 298 norm = sqrt(ax * ax + ay * ay + az * az);
olimexsmart 0:32b177f0030e 299 if (norm == 0.0f) return; // handle NaN
olimexsmart 0:32b177f0030e 300 norm = 1.0f/norm;
olimexsmart 0:32b177f0030e 301 ax *= norm;
olimexsmart 0:32b177f0030e 302 ay *= norm;
olimexsmart 0:32b177f0030e 303 az *= norm;
olimexsmart 0:32b177f0030e 304
olimexsmart 0:32b177f0030e 305 // Normalise magnetometer measurement
olimexsmart 0:32b177f0030e 306 norm = sqrt(mx * mx + my * my + mz * mz);
olimexsmart 0:32b177f0030e 307 if (norm == 0.0f) return; // handle NaN
olimexsmart 0:32b177f0030e 308 norm = 1.0f/norm;
olimexsmart 0:32b177f0030e 309 mx *= norm;
olimexsmart 0:32b177f0030e 310 my *= norm;
olimexsmart 0:32b177f0030e 311 mz *= norm;
olimexsmart 0:32b177f0030e 312
olimexsmart 0:32b177f0030e 313 // Reference direction of Earth's magnetic field
olimexsmart 0:32b177f0030e 314 _2q1mx = 2.0f * q1 * mx;
olimexsmart 0:32b177f0030e 315 _2q1my = 2.0f * q1 * my;
olimexsmart 0:32b177f0030e 316 _2q1mz = 2.0f * q1 * mz;
olimexsmart 0:32b177f0030e 317 _2q2mx = 2.0f * q2 * mx;
olimexsmart 0:32b177f0030e 318 hx = mx * q1q1 - _2q1my * q4 + _2q1mz * q3 + mx * q2q2 + _2q2 * my * q3 + _2q2 * mz * q4 - mx * q3q3 - mx * q4q4;
olimexsmart 0:32b177f0030e 319 hy = _2q1mx * q4 + my * q1q1 - _2q1mz * q2 + _2q2mx * q3 - my * q2q2 + my * q3q3 + _2q3 * mz * q4 - my * q4q4;
olimexsmart 0:32b177f0030e 320 _2bx = sqrt(hx * hx + hy * hy);
olimexsmart 0:32b177f0030e 321 _2bz = -_2q1mx * q3 + _2q1my * q2 + mz * q1q1 + _2q2mx * q4 - mz * q2q2 + _2q3 * my * q4 - mz * q3q3 + mz * q4q4;
olimexsmart 0:32b177f0030e 322 _4bx = 2.0f * _2bx;
olimexsmart 0:32b177f0030e 323 _4bz = 2.0f * _2bz;
olimexsmart 0:32b177f0030e 324
olimexsmart 0:32b177f0030e 325 // Gradient decent algorithm corrective step
olimexsmart 0:32b177f0030e 326 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);
olimexsmart 0:32b177f0030e 327 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);
olimexsmart 0:32b177f0030e 328 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);
olimexsmart 0:32b177f0030e 329 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);
olimexsmart 0:32b177f0030e 330 norm = sqrt(s1 * s1 + s2 * s2 + s3 * s3 + s4 * s4); // normalise step magnitude
olimexsmart 0:32b177f0030e 331 norm = 1.0f/norm;
olimexsmart 0:32b177f0030e 332 s1 *= norm;
olimexsmart 0:32b177f0030e 333 s2 *= norm;
olimexsmart 0:32b177f0030e 334 s3 *= norm;
olimexsmart 0:32b177f0030e 335 s4 *= norm;
olimexsmart 0:32b177f0030e 336
olimexsmart 0:32b177f0030e 337 // Compute rate of change of quaternion
olimexsmart 0:32b177f0030e 338 qDot1 = 0.5f * (-q2 * gx - q3 * gy - q4 * gz) - beta * s1;
olimexsmart 0:32b177f0030e 339 qDot2 = 0.5f * (q1 * gx + q3 * gz - q4 * gy) - beta * s2;
olimexsmart 0:32b177f0030e 340 qDot3 = 0.5f * (q1 * gy - q2 * gz + q4 * gx) - beta * s3;
olimexsmart 0:32b177f0030e 341 qDot4 = 0.5f * (q1 * gz + q2 * gy - q3 * gx) - beta * s4;
olimexsmart 0:32b177f0030e 342
olimexsmart 0:32b177f0030e 343 // Integrate to yield quaternion
olimexsmart 0:32b177f0030e 344 q1 += qDot1 * deltat;
olimexsmart 0:32b177f0030e 345 q2 += qDot2 * deltat;
olimexsmart 0:32b177f0030e 346 q3 += qDot3 * deltat;
olimexsmart 0:32b177f0030e 347 q4 += qDot4 * deltat;
olimexsmart 0:32b177f0030e 348 norm = sqrt(q1 * q1 + q2 * q2 + q3 * q3 + q4 * q4); // normalise quaternion
olimexsmart 0:32b177f0030e 349 norm = 1.0f/norm;
olimexsmart 0:32b177f0030e 350 q[0] = q1 * norm;
olimexsmart 0:32b177f0030e 351 q[1] = q2 * norm;
olimexsmart 0:32b177f0030e 352 q[2] = q3 * norm;
olimexsmart 0:32b177f0030e 353 q[3] = q4 * norm;
olimexsmart 0:32b177f0030e 354
olimexsmart 0:32b177f0030e 355 }
olimexsmart 0:32b177f0030e 356
olimexsmart 0:32b177f0030e 357
olimexsmart 0:32b177f0030e 358
olimexsmart 0:32b177f0030e 359 // Similar to Madgwick scheme but uses proportional and integral filtering on the error between estimated reference vectors and
olimexsmart 0:32b177f0030e 360 // measured ones.
olimexsmart 0:32b177f0030e 361 void MahonyQuaternionUpdate(float ax, float ay, float az, float gx, float gy, float gz, float mx, float my, float mz)
olimexsmart 0:32b177f0030e 362 {
olimexsmart 0:32b177f0030e 363 float q1 = q[0], q2 = q[1], q3 = q[2], q4 = q[3]; // short name local variable for readability
olimexsmart 0:32b177f0030e 364 float norm;
olimexsmart 0:32b177f0030e 365 float hx, hy, bx, bz;
olimexsmart 0:32b177f0030e 366 float vx, vy, vz, wx, wy, wz;
olimexsmart 0:32b177f0030e 367 float ex, ey, ez;
olimexsmart 0:32b177f0030e 368 float pa, pb, pc;
olimexsmart 0:32b177f0030e 369
olimexsmart 0:32b177f0030e 370 // Auxiliary variables to avoid repeated arithmetic
olimexsmart 0:32b177f0030e 371 float q1q1 = q1 * q1;
olimexsmart 0:32b177f0030e 372 float q1q2 = q1 * q2;
olimexsmart 0:32b177f0030e 373 float q1q3 = q1 * q3;
olimexsmart 0:32b177f0030e 374 float q1q4 = q1 * q4;
olimexsmart 0:32b177f0030e 375 float q2q2 = q2 * q2;
olimexsmart 0:32b177f0030e 376 float q2q3 = q2 * q3;
olimexsmart 0:32b177f0030e 377 float q2q4 = q2 * q4;
olimexsmart 0:32b177f0030e 378 float q3q3 = q3 * q3;
olimexsmart 0:32b177f0030e 379 float q3q4 = q3 * q4;
olimexsmart 0:32b177f0030e 380 float q4q4 = q4 * q4;
olimexsmart 0:32b177f0030e 381
olimexsmart 0:32b177f0030e 382 // Normalise accelerometer measurement
olimexsmart 0:32b177f0030e 383 norm = sqrt(ax * ax + ay * ay + az * az);
olimexsmart 0:32b177f0030e 384 if (norm == 0.0f) return; // handle NaN
olimexsmart 0:32b177f0030e 385 norm = 1.0f / norm; // use reciprocal for division
olimexsmart 0:32b177f0030e 386 ax *= norm;
olimexsmart 0:32b177f0030e 387 ay *= norm;
olimexsmart 0:32b177f0030e 388 az *= norm;
olimexsmart 0:32b177f0030e 389
olimexsmart 0:32b177f0030e 390 // Normalise magnetometer measurement
olimexsmart 0:32b177f0030e 391 norm = sqrt(mx * mx + my * my + mz * mz);
olimexsmart 0:32b177f0030e 392 if (norm == 0.0f) return; // handle NaN
olimexsmart 0:32b177f0030e 393 norm = 1.0f / norm; // use reciprocal for division
olimexsmart 0:32b177f0030e 394 mx *= norm;
olimexsmart 0:32b177f0030e 395 my *= norm;
olimexsmart 0:32b177f0030e 396 mz *= norm;
olimexsmart 0:32b177f0030e 397
olimexsmart 0:32b177f0030e 398 // Reference direction of Earth's magnetic field
olimexsmart 0:32b177f0030e 399 hx = 2.0f * mx * (0.5f - q3q3 - q4q4) + 2.0f * my * (q2q3 - q1q4) + 2.0f * mz * (q2q4 + q1q3);
olimexsmart 0:32b177f0030e 400 hy = 2.0f * mx * (q2q3 + q1q4) + 2.0f * my * (0.5f - q2q2 - q4q4) + 2.0f * mz * (q3q4 - q1q2);
olimexsmart 0:32b177f0030e 401 bx = sqrt((hx * hx) + (hy * hy));
olimexsmart 0:32b177f0030e 402 bz = 2.0f * mx * (q2q4 - q1q3) + 2.0f * my * (q3q4 + q1q2) + 2.0f * mz * (0.5f - q2q2 - q3q3);
olimexsmart 0:32b177f0030e 403
olimexsmart 0:32b177f0030e 404 // Estimated direction of gravity and magnetic field
olimexsmart 0:32b177f0030e 405 vx = 2.0f * (q2q4 - q1q3);
olimexsmart 0:32b177f0030e 406 vy = 2.0f * (q1q2 + q3q4);
olimexsmart 0:32b177f0030e 407 vz = q1q1 - q2q2 - q3q3 + q4q4;
olimexsmart 0:32b177f0030e 408 wx = 2.0f * bx * (0.5f - q3q3 - q4q4) + 2.0f * bz * (q2q4 - q1q3);
olimexsmart 0:32b177f0030e 409 wy = 2.0f * bx * (q2q3 - q1q4) + 2.0f * bz * (q1q2 + q3q4);
olimexsmart 0:32b177f0030e 410 wz = 2.0f * bx * (q1q3 + q2q4) + 2.0f * bz * (0.5f - q2q2 - q3q3);
olimexsmart 0:32b177f0030e 411
olimexsmart 0:32b177f0030e 412 // Error is cross product between estimated direction and measured direction of gravity
olimexsmart 0:32b177f0030e 413 ex = (ay * vz - az * vy) + (my * wz - mz * wy);
olimexsmart 0:32b177f0030e 414 ey = (az * vx - ax * vz) + (mz * wx - mx * wz);
olimexsmart 0:32b177f0030e 415 ez = (ax * vy - ay * vx) + (mx * wy - my * wx);
olimexsmart 0:32b177f0030e 416 if (Ki > 0.0f) {
olimexsmart 0:32b177f0030e 417 eInt[0] += ex; // accumulate integral error
olimexsmart 0:32b177f0030e 418 eInt[1] += ey;
olimexsmart 0:32b177f0030e 419 eInt[2] += ez;
olimexsmart 0:32b177f0030e 420 } else {
olimexsmart 0:32b177f0030e 421 eInt[0] = 0.0f; // prevent integral wind up
olimexsmart 0:32b177f0030e 422 eInt[1] = 0.0f;
olimexsmart 0:32b177f0030e 423 eInt[2] = 0.0f;
olimexsmart 0:32b177f0030e 424 }
olimexsmart 0:32b177f0030e 425
olimexsmart 0:32b177f0030e 426 // Apply feedback terms
olimexsmart 0:32b177f0030e 427 gx = gx + Kp * ex + Ki * eInt[0];
olimexsmart 0:32b177f0030e 428 gy = gy + Kp * ey + Ki * eInt[1];
olimexsmart 0:32b177f0030e 429 gz = gz + Kp * ez + Ki * eInt[2];
olimexsmart 0:32b177f0030e 430
olimexsmart 0:32b177f0030e 431 // Integrate rate of change of quaternion
olimexsmart 0:32b177f0030e 432 pa = q2;
olimexsmart 0:32b177f0030e 433 pb = q3;
olimexsmart 0:32b177f0030e 434 pc = q4;
olimexsmart 0:32b177f0030e 435 q1 = q1 + (-q2 * gx - q3 * gy - q4 * gz) * (0.5f * deltat);
olimexsmart 0:32b177f0030e 436 q2 = pa + (q1 * gx + pb * gz - pc * gy) * (0.5f * deltat);
olimexsmart 0:32b177f0030e 437 q3 = pb + (q1 * gy - pa * gz + pc * gx) * (0.5f * deltat);
olimexsmart 0:32b177f0030e 438 q4 = pc + (q1 * gz + pa * gy - pb * gx) * (0.5f * deltat);
olimexsmart 0:32b177f0030e 439
olimexsmart 0:32b177f0030e 440 // Normalise quaternion
olimexsmart 0:32b177f0030e 441 norm = sqrt(q1 * q1 + q2 * q2 + q3 * q3 + q4 * q4);
olimexsmart 0:32b177f0030e 442 norm = 1.0f / norm;
olimexsmart 0:32b177f0030e 443 q[0] = q1 * norm;
olimexsmart 0:32b177f0030e 444 q[1] = q2 * norm;
olimexsmart 0:32b177f0030e 445 q[2] = q3 * norm;
olimexsmart 0:32b177f0030e 446 q[3] = q4 * norm;
olimexsmart 0:32b177f0030e 447
olimexsmart 0:32b177f0030e 448 }