Kris Winer
Basic program to obtain properly-scaled gyro, accelerometer, and magnetometer data from the MPU-9150 9-axis motion sensor. Nine-axis sensor fusion with Sebastian Madgwick's and Mahony's open-source sensor fusion filters running on an STM32F401RE Nucleo board at 84 MHz achieve sensor fusion filter update rates of ~5000 Hz. Additional info at https://github.com/kriswiner/STM32F401.
Dependencies: ST_401_84MHZ mbed
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MPU9150.h
00001 #ifndef MPU9150_H 00002 #define MPU9150_H 00003 00004 #include "mbed.h" 00005 00006 // Define registers per MPU6050, Register Map and Descriptions, Rev 4.2, 08/19/2013 6 DOF Motion sensor fusion device 00007 // Invensense Inc., www.invensense.com 00008 // See also MPU-9150 Register Map and Descriptions, Revision 4.0, RM-MPU-9150A-00, 9/12/2012 for registers not listed in 00009 // above document; the MPU6050 and MPU 9150 are virtually identical but the latter has an on-board magnetic sensor 00010 // 00011 //Magnetometer Registers 00012 #define WHO_AM_I_AK8975A 0x00 // should return 0x48 00013 #define INFO 0x01 00014 #define AK8975A_ST1 0x02 // data ready status bit 0 00015 #define AK8975A_ADDRESS 0x0C<<1 00016 #define AK8975A_XOUT_L 0x03 // data 00017 #define AK8975A_XOUT_H 0x04 00018 #define AK8975A_YOUT_L 0x05 00019 #define AK8975A_YOUT_H 0x06 00020 #define AK8975A_ZOUT_L 0x07 00021 #define AK8975A_ZOUT_H 0x08 00022 #define AK8975A_ST2 0x09 // Data overflow bit 3 and data read error status bit 2 00023 #define AK8975A_CNTL 0x0A // Power down (0000), single-measurement (0001), self-test (1000) and Fuse ROM (1111) modes on bits 3:0 00024 #define AK8975A_ASTC 0x0C // Self test control 00025 #define AK8975A_ASAX 0x10 // Fuse ROM x-axis sensitivity adjustment value 00026 #define AK8975A_ASAY 0x11 // Fuse ROM y-axis sensitivity adjustment value 00027 #define AK8975A_ASAZ 0x12 // Fuse ROM z-axis sensitivity adjustment value 00028 00029 #define XGOFFS_TC 0x00 // Bit 7 PWR_MODE, bits 6:1 XG_OFFS_TC, bit 0 OTP_BNK_VLD 00030 #define YGOFFS_TC 0x01 00031 #define ZGOFFS_TC 0x02 00032 #define X_FINE_GAIN 0x03 // [7:0] fine gain 00033 #define Y_FINE_GAIN 0x04 00034 #define Z_FINE_GAIN 0x05 00035 #define XA_OFFSET_H 0x06 // User-defined trim values for accelerometer 00036 #define XA_OFFSET_L_TC 0x07 00037 #define YA_OFFSET_H 0x08 00038 #define YA_OFFSET_L_TC 0x09 00039 #define ZA_OFFSET_H 0x0A 00040 #define ZA_OFFSET_L_TC 0x0B 00041 #define SELF_TEST_X 0x0D 00042 #define SELF_TEST_Y 0x0E 00043 #define SELF_TEST_Z 0x0F 00044 #define SELF_TEST_A 0x10 00045 #define XG_OFFS_USRH 0x13 // User-defined trim values for gyroscope, populate with calibration routine 00046 #define XG_OFFS_USRL 0x14 00047 #define YG_OFFS_USRH 0x15 00048 #define YG_OFFS_USRL 0x16 00049 #define ZG_OFFS_USRH 0x17 00050 #define ZG_OFFS_USRL 0x18 00051 #define SMPLRT_DIV 0x19 00052 #define CONFIG 0x1A 00053 #define GYRO_CONFIG 0x1B 00054 #define ACCEL_CONFIG 0x1C 00055 #define FF_THR 0x1D // Free-fall 00056 #define FF_DUR 0x1E // Free-fall 00057 #define MOT_THR 0x1F // Motion detection threshold bits [7:0] 00058 #define MOT_DUR 0x20 // Duration counter threshold for motion interrupt generation, 1 kHz rate, LSB = 1 ms 00059 #define ZMOT_THR 0x21 // Zero-motion detection threshold bits [7:0] 00060 #define ZRMOT_DUR 0x22 // Duration counter threshold for zero motion interrupt generation, 16 Hz rate, LSB = 64 ms 00061 #define FIFO_EN 0x23 00062 #define I2C_MST_CTRL 0x24 00063 #define I2C_SLV0_ADDR 0x25 00064 #define I2C_SLV0_REG 0x26 00065 #define I2C_SLV0_CTRL 0x27 00066 #define I2C_SLV1_ADDR 0x28 00067 #define I2C_SLV1_REG 0x29 00068 #define I2C_SLV1_CTRL 0x2A 00069 #define I2C_SLV2_ADDR 0x2B 00070 #define I2C_SLV2_REG 0x2C 00071 #define I2C_SLV2_CTRL 0x2D 00072 #define I2C_SLV3_ADDR 0x2E 00073 #define I2C_SLV3_REG 0x2F 00074 #define I2C_SLV3_CTRL 0x30 00075 #define I2C_SLV4_ADDR 0x31 00076 #define I2C_SLV4_REG 0x32 00077 #define I2C_SLV4_DO 0x33 00078 #define I2C_SLV4_CTRL 0x34 00079 #define I2C_SLV4_DI 0x35 00080 #define I2C_MST_STATUS 0x36 00081 #define INT_PIN_CFG 0x37 00082 #define INT_ENABLE 0x38 00083 #define DMP_INT_STATUS 0x39 // Check DMP interrupt 00084 #define INT_STATUS 0x3A 00085 #define ACCEL_XOUT_H 0x3B 00086 #define ACCEL_XOUT_L 0x3C 00087 #define ACCEL_YOUT_H 0x3D 00088 #define ACCEL_YOUT_L 0x3E 00089 #define ACCEL_ZOUT_H 0x3F 00090 #define ACCEL_ZOUT_L 0x40 00091 #define TEMP_OUT_H 0x41 00092 #define TEMP_OUT_L 0x42 00093 #define GYRO_XOUT_H 0x43 00094 #define GYRO_XOUT_L 0x44 00095 #define GYRO_YOUT_H 0x45 00096 #define GYRO_YOUT_L 0x46 00097 #define GYRO_ZOUT_H 0x47 00098 #define GYRO_ZOUT_L 0x48 00099 #define EXT_SENS_DATA_00 0x49 00100 #define EXT_SENS_DATA_01 0x4A 00101 #define EXT_SENS_DATA_02 0x4B 00102 #define EXT_SENS_DATA_03 0x4C 00103 #define EXT_SENS_DATA_04 0x4D 00104 #define EXT_SENS_DATA_05 0x4E 00105 #define EXT_SENS_DATA_06 0x4F 00106 #define EXT_SENS_DATA_07 0x50 00107 #define EXT_SENS_DATA_08 0x51 00108 #define EXT_SENS_DATA_09 0x52 00109 #define EXT_SENS_DATA_10 0x53 00110 #define EXT_SENS_DATA_11 0x54 00111 #define EXT_SENS_DATA_12 0x55 00112 #define EXT_SENS_DATA_13 0x56 00113 #define EXT_SENS_DATA_14 0x57 00114 #define EXT_SENS_DATA_15 0x58 00115 #define EXT_SENS_DATA_16 0x59 00116 #define EXT_SENS_DATA_17 0x5A 00117 #define EXT_SENS_DATA_18 0x5B 00118 #define EXT_SENS_DATA_19 0x5C 00119 #define EXT_SENS_DATA_20 0x5D 00120 #define EXT_SENS_DATA_21 0x5E 00121 #define EXT_SENS_DATA_22 0x5F 00122 #define EXT_SENS_DATA_23 0x60 00123 #define MOT_DETECT_STATUS 0x61 00124 #define I2C_SLV0_DO 0x63 00125 #define I2C_SLV1_DO 0x64 00126 #define I2C_SLV2_DO 0x65 00127 #define I2C_SLV3_DO 0x66 00128 #define I2C_MST_DELAY_CTRL 0x67 00129 #define SIGNAL_PATH_RESET 0x68 00130 #define MOT_DETECT_CTRL 0x69 00131 #define USER_CTRL 0x6A // Bit 7 enable DMP, bit 3 reset DMP 00132 #define PWR_MGMT_1 0x6B // Device defaults to the SLEEP mode 00133 #define PWR_MGMT_2 0x6C 00134 #define DMP_BANK 0x6D // Activates a specific bank in the DMP 00135 #define DMP_RW_PNT 0x6E // Set read/write pointer to a specific start address in specified DMP bank 00136 #define DMP_REG 0x6F // Register in DMP from which to read or to which to write 00137 #define DMP_REG_1 0x70 00138 #define DMP_REG_2 0x71 00139 #define FIFO_COUNTH 0x72 00140 #define FIFO_COUNTL 0x73 00141 #define FIFO_R_W 0x74 00142 #define WHO_AM_I_MPU9150 0x75 // Should return 0x68 00143 00144 00145 // Using the GY-9150 breakout board, ADO is set to 0 00146 // Seven-bit device address is 110100 for ADO = 0 and 110101 for ADO = 1 00147 // mbed uses the eight-bit device address, so shift seven-bit addresses left by one! 00148 #define ADO 0 00149 #if ADO 00150 #define MPU9150_ADDRESS 0x69<<1 // Device address when ADO = 1 00151 #else 00152 #define MPU9150_ADDRESS 0x68<<1 // Device address when ADO = 0 00153 #endif 00154 00155 // Set initial input parameters 00156 enum Ascale { 00157 AFS_2G = 0, 00158 AFS_4G, 00159 AFS_8G, 00160 AFS_16G 00161 }; 00162 00163 enum Gscale { 00164 GFS_250DPS = 0, 00165 GFS_500DPS, 00166 GFS_1000DPS, 00167 GFS_2000DPS 00168 }; 00169 00170 uint8_t Ascale = AFS_2G; // AFS_2G, AFS_4G, AFS_8G, AFS_16G 00171 uint8_t Gscale = GFS_250DPS; // GFS_250DPS, GFS_500DPS, GFS_1000DPS, GFS_2000DPS 00172 float aRes, gRes, mRes; // scale resolutions per LSB for the sensors 00173 00174 //Set up I2C, (SDA,SCL) 00175 I2C i2c(I2C_SDA, I2C_SCL); 00176 00177 DigitalOut myled(LED1); 00178 00179 // Pin definitions 00180 int intPin = 12; // These can be changed, 2 and 3 are the Arduinos ext int pins 00181 00182 int16_t accelCount[3]; // Stores the 16-bit signed accelerometer sensor output 00183 int16_t gyroCount[3]; // Stores the 16-bit signed gyro sensor output 00184 int16_t magCount[3]; // Stores the 16-bit signed magnetometer sensor output 00185 float magCalibration[3] = {0, 0, 0}, magbias[3] = {0, 0, 0}; // Factory mag calibration and mag bias 00186 float gyroBias[3] = {0, 0, 0}, accelBias[3] = {0, 0, 0}; // Bias corrections for gyro and accelerometer 00187 float ax, ay, az, gx, gy, gz, mx, my, mz; // variables to hold latest sensor data values 00188 int16_t tempCount; // Stores the real internal chip temperature in degrees Celsius 00189 float temperature; 00190 float SelfTest[6]; 00191 00192 int delt_t = 0; // used to control display output rate 00193 int count = 0; // used to control display output rate 00194 00195 // parameters for 6 DoF sensor fusion calculations 00196 float PI = 3.14159265358979323846f; 00197 float GyroMeasError = PI * (60.0f / 180.0f); // gyroscope measurement error in rads/s (start at 60 deg/s), then reduce after ~10 s to 3 00198 float beta = sqrt(3.0f / 4.0f) * GyroMeasError; // compute beta 00199 float GyroMeasDrift = PI * (1.0f / 180.0f); // gyroscope measurement drift in rad/s/s (start at 0.0 deg/s/s) 00200 float 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 00201 #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 00202 #define Ki 0.0f 00203 00204 float pitch, yaw, roll; 00205 float deltat = 0.0f; // integration interval for both filter schemes 00206 int lastUpdate = 0, firstUpdate = 0, Now = 0; // used to calculate integration interval // used to calculate integration interval 00207 float q[4] = {1.0f, 0.0f, 0.0f, 0.0f}; // vector to hold quaternion 00208 float eInt[3] = {0.0f, 0.0f, 0.0f}; // vector to hold integral error for Mahony method 00209 00210 class MPU9150 { 00211 00212 protected: 00213 00214 public: 00215 //=================================================================================================================== 00216 //====== Set of useful function to access acceleratio, gyroscope, and temperature data 00217 //=================================================================================================================== 00218 00219 void writeByte(uint8_t address, uint8_t subAddress, uint8_t data) 00220 { 00221 char data_write[2]; 00222 data_write[0] = subAddress; 00223 data_write[1] = data; 00224 i2c.write(address, data_write, 2, 0); 00225 } 00226 00227 char readByte(uint8_t address, uint8_t subAddress) 00228 { 00229 char data[1]; // `data` will store the register data 00230 char data_write[1]; 00231 data_write[0] = subAddress; 00232 i2c.write(address, data_write, 1, 1); // no stop 00233 i2c.read(address, data, 1, 0); 00234 return data[0]; 00235 } 00236 00237 void readBytes(uint8_t address, uint8_t subAddress, uint8_t count, uint8_t * dest) 00238 { 00239 char data[14]; 00240 char data_write[1]; 00241 data_write[0] = subAddress; 00242 i2c.write(address, data_write, 1, 1); // no stop 00243 i2c.read(address, data, count, 0); 00244 for(int ii = 0; ii < count; ii++) { 00245 dest[ii] = data[ii]; 00246 } 00247 } 00248 00249 00250 void getGres() { 00251 switch (Gscale) 00252 { 00253 // Possible gyro scales (and their register bit settings) are: 00254 // 250 DPS (00), 500 DPS (01), 1000 DPS (10), and 2000 DPS (11). 00255 // Here's a bit of an algorith to calculate DPS/(ADC tick) based on that 2-bit value: 00256 case GFS_250DPS: 00257 gRes = 250.0/32768.0; 00258 break; 00259 case GFS_500DPS: 00260 gRes = 500.0/32768.0; 00261 break; 00262 case GFS_1000DPS: 00263 gRes = 1000.0/32768.0; 00264 break; 00265 case GFS_2000DPS: 00266 gRes = 2000.0/32768.0; 00267 break; 00268 } 00269 } 00270 00271 00272 void getAres() { 00273 switch (Ascale) 00274 { 00275 // Possible accelerometer scales (and their register bit settings) are: 00276 // 2 Gs (00), 4 Gs (01), 8 Gs (10), and 16 Gs (11). 00277 // Here's a bit of an algorith to calculate DPS/(ADC tick) based on that 2-bit value: 00278 case AFS_2G: 00279 aRes = 2.0/32768.0; 00280 break; 00281 case AFS_4G: 00282 aRes = 4.0/32768.0; 00283 break; 00284 case AFS_8G: 00285 aRes = 8.0/32768.0; 00286 break; 00287 case AFS_16G: 00288 aRes = 16.0/32768.0; 00289 break; 00290 } 00291 } 00292 00293 00294 void readAccelData(int16_t * destination) 00295 { 00296 uint8_t rawData[6]; // x/y/z accel register data stored here 00297 readBytes(MPU9150_ADDRESS, ACCEL_XOUT_H, 6, &rawData[0]); // Read the six raw data registers into data array 00298 destination[0] = (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value 00299 destination[1] = (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; 00300 destination[2] = (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 00301 } 00302 00303 void readGyroData(int16_t * destination) 00304 { 00305 uint8_t rawData[6]; // x/y/z gyro register data stored here 00306 readBytes(MPU9150_ADDRESS, GYRO_XOUT_H, 6, &rawData[0]); // Read the six raw data registers sequentially into data array 00307 destination[0] = (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value 00308 destination[1] = (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; 00309 destination[2] = (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 00310 } 00311 00312 void readMagData(int16_t * destination) 00313 { 00314 uint8_t rawData[6]; // x/y/z gyro register data stored here 00315 writeByte(AK8975A_ADDRESS, AK8975A_CNTL, 0x01); // toggle enable data read from magnetometer, no continuous read mode! 00316 wait(0.01); 00317 // Only accept a new magnetometer data read if the data ready bit is set and 00318 // if there are no sensor overflow or data read errors 00319 if(readByte(AK8975A_ADDRESS, AK8975A_ST1) & 0x01) { // wait for magnetometer data ready bit to be set 00320 readBytes(AK8975A_ADDRESS, AK8975A_XOUT_L, 6, &rawData[0]); // Read the six raw data registers sequentially into data array 00321 destination[0] = ((int16_t)rawData[1] << 8) | rawData[0] ; // Turn the MSB and LSB into a signed 16-bit value 00322 destination[1] = ((int16_t)rawData[3] << 8) | rawData[2] ; 00323 destination[2] = ((int16_t)rawData[5] << 8) | rawData[4] ; 00324 } 00325 } 00326 00327 void initAK8975A(float * destination) 00328 { 00329 uint8_t rawData[3]; // x/y/z gyro register data stored here 00330 writeByte(AK8975A_ADDRESS, AK8975A_CNTL, 0x00); // Power down 00331 wait(0.01); 00332 writeByte(AK8975A_ADDRESS, AK8975A_CNTL, 0x0F); // Enter Fuse ROM access mode 00333 wait(0.01); 00334 readBytes(AK8975A_ADDRESS, AK8975A_ASAX, 3, &rawData[0]); // Read the x-, y-, and z-axis calibration values 00335 destination[0] = (float)(rawData[0] - 128)/256.0f + 1.0f; // Return x-axis sensitivity adjustment values 00336 destination[1] = (float)(rawData[1] - 128)/256.0f + 1.0f; 00337 destination[2] = (float)(rawData[2] - 128)/256.0f + 1.0f; 00338 } 00339 00340 int16_t readTempData() 00341 { 00342 uint8_t rawData[2]; // x/y/z gyro register data stored here 00343 readBytes(MPU9150_ADDRESS, TEMP_OUT_H, 2, &rawData[0]); // Read the two raw data registers sequentially into data array 00344 return ((int16_t)rawData[0] << 8) | rawData[1] ; // Turn the MSB and LSB into a 16-bit value 00345 } 00346 00347 void resetMPU9150() { 00348 // reset device 00349 writeByte(MPU9150_ADDRESS, PWR_MGMT_1, 0x80); // Write a one to bit 7 reset bit; toggle reset device 00350 wait(0.1); 00351 } 00352 00353 00354 00355 void initMPU9150() 00356 { 00357 // Initialize MPU9150 device 00358 // wake up device 00359 writeByte(MPU9150_ADDRESS, PWR_MGMT_1, 0x00); // Clear sleep mode bit (6), enable all sensors 00360 wait(0.1); // Delay 100 ms for PLL to get established on x-axis gyro; should check for PLL ready interrupt 00361 00362 // get stable time source 00363 writeByte(MPU9150_ADDRESS, PWR_MGMT_1, 0x01); // Set clock source to be PLL with x-axis gyroscope reference, bits 2:0 = 001 00364 00365 // Configure Gyro and Accelerometer 00366 // Disable FSYNC and set accelerometer and gyro bandwidth to 44 and 42 Hz, respectively; 00367 // DLPF_CFG = bits 2:0 = 010; this sets the sample rate at 1 kHz for both 00368 // Maximum delay is 4.9 ms which is just over a 200 Hz maximum rate 00369 writeByte(MPU9150_ADDRESS, CONFIG, 0x03); 00370 00371 // Set sample rate = gyroscope output rate/(1 + SMPLRT_DIV) 00372 writeByte(MPU9150_ADDRESS, SMPLRT_DIV, 0x04); // Use a 200 Hz rate; the same rate set in CONFIG above 00373 00374 // Set gyroscope full scale range 00375 // Range selects FS_SEL and AFS_SEL are 0 - 3, so 2-bit values are left-shifted into positions 4:3 00376 uint8_t c = readByte(MPU9150_ADDRESS, GYRO_CONFIG); 00377 writeByte(MPU9150_ADDRESS, GYRO_CONFIG, c & ~0xE0); // Clear self-test bits [7:5] 00378 writeByte(MPU9150_ADDRESS, GYRO_CONFIG, c & ~0x18); // Clear AFS bits [4:3] 00379 writeByte(MPU9150_ADDRESS, GYRO_CONFIG, c | Gscale << 3); // Set full scale range for the gyro 00380 00381 // Set accelerometer configuration 00382 c = readByte(MPU9150_ADDRESS, ACCEL_CONFIG); 00383 writeByte(MPU9150_ADDRESS, ACCEL_CONFIG, c & ~0xE0); // Clear self-test bits [7:5] 00384 writeByte(MPU9150_ADDRESS, ACCEL_CONFIG, c & ~0x18); // Clear AFS bits [4:3] 00385 writeByte(MPU9150_ADDRESS, ACCEL_CONFIG, c | Ascale << 3); // Set full scale range for the accelerometer 00386 00387 // The accelerometer, gyro, and thermometer are set to 1 kHz sample rates, 00388 // but all these rates are further reduced by a factor of 5 to 200 Hz because of the SMPLRT_DIV setting 00389 00390 // Configure Interrupts and Bypass Enable 00391 // Set interrupt pin active high, push-pull, and clear on read of INT_STATUS, enable I2C_BYPASS_EN so additional chips 00392 // can join the I2C bus and all can be controlled by the Arduino as master 00393 writeByte(MPU9150_ADDRESS, INT_PIN_CFG, 0x22); 00394 writeByte(MPU9150_ADDRESS, INT_ENABLE, 0x01); // Enable data ready (bit 0) interrupt 00395 } 00396 00397 // Function which accumulates gyro and accelerometer data after device initialization. It calculates the average 00398 // of the at-rest readings and then loads the resulting offsets into accelerometer and gyro bias registers. 00399 void calibrateMPU9150(float * dest1, float * dest2) 00400 { 00401 uint8_t data[12]; // data array to hold accelerometer and gyro x, y, z, data 00402 uint16_t ii, packet_count, fifo_count; 00403 int32_t gyro_bias[3] = {0, 0, 0}, accel_bias[3] = {0, 0, 0}; 00404 00405 // reset device, reset all registers, clear gyro and accelerometer bias registers 00406 writeByte(MPU9150_ADDRESS, PWR_MGMT_1, 0x80); // Write a one to bit 7 reset bit; toggle reset device 00407 wait(0.1); 00408 00409 // get stable time source 00410 // Set clock source to be PLL with x-axis gyroscope reference, bits 2:0 = 001 00411 writeByte(MPU9150_ADDRESS, PWR_MGMT_1, 0x01); 00412 writeByte(MPU9150_ADDRESS, PWR_MGMT_2, 0x00); 00413 wait(0.2); 00414 00415 // Configure device for bias calculation 00416 writeByte(MPU9150_ADDRESS, INT_ENABLE, 0x00); // Disable all interrupts 00417 writeByte(MPU9150_ADDRESS, FIFO_EN, 0x00); // Disable FIFO 00418 writeByte(MPU9150_ADDRESS, PWR_MGMT_1, 0x00); // Turn on internal clock source 00419 writeByte(MPU9150_ADDRESS, I2C_MST_CTRL, 0x00); // Disable I2C master 00420 writeByte(MPU9150_ADDRESS, USER_CTRL, 0x00); // Disable FIFO and I2C master modes 00421 writeByte(MPU9150_ADDRESS, USER_CTRL, 0x0C); // Reset FIFO and DMP 00422 wait(0.015); 00423 00424 // Configure MPU9150 gyro and accelerometer for bias calculation 00425 writeByte(MPU9150_ADDRESS, CONFIG, 0x01); // Set low-pass filter to 188 Hz 00426 writeByte(MPU9150_ADDRESS, SMPLRT_DIV, 0x00); // Set sample rate to 1 kHz 00427 writeByte(MPU9150_ADDRESS, GYRO_CONFIG, 0x00); // Set gyro full-scale to 250 degrees per second, maximum sensitivity 00428 writeByte(MPU9150_ADDRESS, ACCEL_CONFIG, 0x00); // Set accelerometer full-scale to 2 g, maximum sensitivity 00429 00430 uint16_t gyrosensitivity = 131; // = 131 LSB/degrees/sec 00431 uint16_t accelsensitivity = 16384; // = 16384 LSB/g 00432 00433 // Configure FIFO to capture accelerometer and gyro data for bias calculation 00434 writeByte(MPU9150_ADDRESS, USER_CTRL, 0x40); // Enable FIFO 00435 writeByte(MPU9150_ADDRESS, FIFO_EN, 0x78); // Enable gyro and accelerometer sensors for FIFO (max size 1024 bytes in MPU9150) 00436 wait(0.08); // accumulate 80 samples in 80 milliseconds = 960 bytes 00437 00438 // At end of sample accumulation, turn off FIFO sensor read 00439 writeByte(MPU9150_ADDRESS, FIFO_EN, 0x00); // Disable gyro and accelerometer sensors for FIFO 00440 readBytes(MPU9150_ADDRESS, FIFO_COUNTH, 2, &data[0]); // read FIFO sample count 00441 fifo_count = ((uint16_t)data[0] << 8) | data[1]; 00442 packet_count = fifo_count/12;// How many sets of full gyro and accelerometer data for averaging 00443 00444 for (ii = 0; ii < packet_count; ii++) { 00445 int16_t accel_temp[3] = {0, 0, 0}, gyro_temp[3] = {0, 0, 0}; 00446 readBytes(MPU9150_ADDRESS, FIFO_R_W, 12, &data[0]); // read data for averaging 00447 accel_temp[0] = (int16_t) (((int16_t)data[0] << 8) | data[1] ) ; // Form signed 16-bit integer for each sample in FIFO 00448 accel_temp[1] = (int16_t) (((int16_t)data[2] << 8) | data[3] ) ; 00449 accel_temp[2] = (int16_t) (((int16_t)data[4] << 8) | data[5] ) ; 00450 gyro_temp[0] = (int16_t) (((int16_t)data[6] << 8) | data[7] ) ; 00451 gyro_temp[1] = (int16_t) (((int16_t)data[8] << 8) | data[9] ) ; 00452 gyro_temp[2] = (int16_t) (((int16_t)data[10] << 8) | data[11]) ; 00453 00454 accel_bias[0] += (int32_t) accel_temp[0]; // Sum individual signed 16-bit biases to get accumulated signed 32-bit biases 00455 accel_bias[1] += (int32_t) accel_temp[1]; 00456 accel_bias[2] += (int32_t) accel_temp[2]; 00457 gyro_bias[0] += (int32_t) gyro_temp[0]; 00458 gyro_bias[1] += (int32_t) gyro_temp[1]; 00459 gyro_bias[2] += (int32_t) gyro_temp[2]; 00460 00461 } 00462 accel_bias[0] /= (int32_t) packet_count; // Normalize sums to get average count biases 00463 accel_bias[1] /= (int32_t) packet_count; 00464 accel_bias[2] /= (int32_t) packet_count; 00465 gyro_bias[0] /= (int32_t) packet_count; 00466 gyro_bias[1] /= (int32_t) packet_count; 00467 gyro_bias[2] /= (int32_t) packet_count; 00468 00469 if(accel_bias[2] > 0L) {accel_bias[2] -= (int32_t) accelsensitivity;} // Remove gravity from the z-axis accelerometer bias calculation 00470 else {accel_bias[2] += (int32_t) accelsensitivity;} 00471 00472 // Construct the gyro biases for push to the hardware gyro bias registers, which are reset to zero upon device startup 00473 data[0] = (-gyro_bias[0]/4 >> 8) & 0xFF; // Divide by 4 to get 32.9 LSB per deg/s to conform to expected bias input format 00474 data[1] = (-gyro_bias[0]/4) & 0xFF; // Biases are additive, so change sign on calculated average gyro biases 00475 data[2] = (-gyro_bias[1]/4 >> 8) & 0xFF; 00476 data[3] = (-gyro_bias[1]/4) & 0xFF; 00477 data[4] = (-gyro_bias[2]/4 >> 8) & 0xFF; 00478 data[5] = (-gyro_bias[2]/4) & 0xFF; 00479 00480 /// Push gyro biases to hardware registers 00481 writeByte(MPU9150_ADDRESS, XG_OFFS_USRH, data[0]); 00482 writeByte(MPU9150_ADDRESS, XG_OFFS_USRL, data[1]); 00483 writeByte(MPU9150_ADDRESS, YG_OFFS_USRH, data[2]); 00484 writeByte(MPU9150_ADDRESS, YG_OFFS_USRL, data[3]); 00485 writeByte(MPU9150_ADDRESS, ZG_OFFS_USRH, data[4]); 00486 writeByte(MPU9150_ADDRESS, ZG_OFFS_USRL, data[5]); 00487 00488 dest1[0] = (float) gyro_bias[0]/(float) gyrosensitivity; // construct gyro bias in deg/s for later manual subtraction 00489 dest1[1] = (float) gyro_bias[1]/(float) gyrosensitivity; 00490 dest1[2] = (float) gyro_bias[2]/(float) gyrosensitivity; 00491 00492 // Construct the accelerometer biases for push to the hardware accelerometer bias registers. These registers contain 00493 // factory trim values which must be added to the calculated accelerometer biases; on boot up these registers will hold 00494 // non-zero values. In addition, bit 0 of the lower byte must be preserved since it is used for temperature 00495 // compensation calculations. Accelerometer bias registers expect bias input as 2048 LSB per g, so that 00496 // the accelerometer biases calculated above must be divided by 8. 00497 00498 int32_t accel_bias_reg[3] = {0, 0, 0}; // A place to hold the factory accelerometer trim biases 00499 readBytes(MPU9150_ADDRESS, XA_OFFSET_H, 2, &data[0]); // Read factory accelerometer trim values 00500 accel_bias_reg[0] = (int16_t) ((int16_t)data[0] << 8) | data[1]; 00501 readBytes(MPU9150_ADDRESS, YA_OFFSET_H, 2, &data[0]); 00502 accel_bias_reg[1] = (int16_t) ((int16_t)data[0] << 8) | data[1]; 00503 readBytes(MPU9150_ADDRESS, ZA_OFFSET_H, 2, &data[0]); 00504 accel_bias_reg[2] = (int16_t) ((int16_t)data[0] << 8) | data[1]; 00505 00506 uint32_t mask = 1uL; // Define mask for temperature compensation bit 0 of lower byte of accelerometer bias registers 00507 uint8_t mask_bit[3] = {0, 0, 0}; // Define array to hold mask bit for each accelerometer bias axis 00508 00509 for(ii = 0; ii < 3; ii++) { 00510 if(accel_bias_reg[ii] & mask) mask_bit[ii] = 0x01; // If temperature compensation bit is set, record that fact in mask_bit 00511 } 00512 00513 // Construct total accelerometer bias, including calculated average accelerometer bias from above 00514 accel_bias_reg[0] -= (accel_bias[0]/8); // Subtract calculated averaged accelerometer bias scaled to 2048 LSB/g (16 g full scale) 00515 accel_bias_reg[1] -= (accel_bias[1]/8); 00516 accel_bias_reg[2] -= (accel_bias[2]/8); 00517 00518 data[0] = (accel_bias_reg[0] >> 8) & 0xFF; 00519 data[1] = (accel_bias_reg[0]) & 0xFF; 00520 data[1] = data[1] | mask_bit[0]; // preserve temperature compensation bit when writing back to accelerometer bias registers 00521 data[2] = (accel_bias_reg[1] >> 8) & 0xFF; 00522 data[3] = (accel_bias_reg[1]) & 0xFF; 00523 data[3] = data[3] | mask_bit[1]; // preserve temperature compensation bit when writing back to accelerometer bias registers 00524 data[4] = (accel_bias_reg[2] >> 8) & 0xFF; 00525 data[5] = (accel_bias_reg[2]) & 0xFF; 00526 data[5] = data[5] | mask_bit[2]; // preserve temperature compensation bit when writing back to accelerometer bias registers 00527 00528 // Apparently this is not working for the acceleration biases in the MPU-9250 00529 // Are we handling the temperature correction bit properly? 00530 // Push accelerometer biases to hardware registers 00531 writeByte(MPU9150_ADDRESS, XA_OFFSET_H, data[0]); 00532 writeByte(MPU9150_ADDRESS, XA_OFFSET_L_TC, data[1]); 00533 writeByte(MPU9150_ADDRESS, YA_OFFSET_H, data[2]); 00534 writeByte(MPU9150_ADDRESS, YA_OFFSET_L_TC, data[3]); 00535 writeByte(MPU9150_ADDRESS, ZA_OFFSET_H, data[4]); 00536 writeByte(MPU9150_ADDRESS, ZA_OFFSET_L_TC, data[5]); 00537 00538 // Output scaled accelerometer biases for manual subtraction in the main program 00539 dest2[0] = (float)accel_bias[0]/(float)accelsensitivity; 00540 dest2[1] = (float)accel_bias[1]/(float)accelsensitivity; 00541 dest2[2] = (float)accel_bias[2]/(float)accelsensitivity; 00542 } 00543 00544 00545 // Accelerometer and gyroscope self test; check calibration wrt factory settings 00546 void MPU9150SelfTest(float * destination) // Should return percent deviation from factory trim values, +/- 14 or less deviation is a pass 00547 { 00548 uint8_t rawData[4] = {0, 0, 0, 0}; 00549 uint8_t selfTest[6]; 00550 float factoryTrim[6]; 00551 00552 // Configure the accelerometer for self-test 00553 writeByte(MPU9150_ADDRESS, ACCEL_CONFIG, 0xF0); // Enable self test on all three axes and set accelerometer range to +/- 8 g 00554 writeByte(MPU9150_ADDRESS, GYRO_CONFIG, 0xE0); // Enable self test on all three axes and set gyro range to +/- 250 degrees/s 00555 wait(0.25); // Delay a while to let the device execute the self-test 00556 rawData[0] = readByte(MPU9150_ADDRESS, SELF_TEST_X); // X-axis self-test results 00557 rawData[1] = readByte(MPU9150_ADDRESS, SELF_TEST_Y); // Y-axis self-test results 00558 rawData[2] = readByte(MPU9150_ADDRESS, SELF_TEST_Z); // Z-axis self-test results 00559 rawData[3] = readByte(MPU9150_ADDRESS, SELF_TEST_A); // Mixed-axis self-test results 00560 // Extract the acceleration test results first 00561 selfTest[0] = (rawData[0] >> 3) | (rawData[3] & 0x30) >> 4 ; // XA_TEST result is a five-bit unsigned integer 00562 selfTest[1] = (rawData[1] >> 3) | (rawData[3] & 0x0C) >> 4 ; // YA_TEST result is a five-bit unsigned integer 00563 selfTest[2] = (rawData[2] >> 3) | (rawData[3] & 0x03) >> 4 ; // ZA_TEST result is a five-bit unsigned integer 00564 // Extract the gyration test results first 00565 selfTest[3] = rawData[0] & 0x1F ; // XG_TEST result is a five-bit unsigned integer 00566 selfTest[4] = rawData[1] & 0x1F ; // YG_TEST result is a five-bit unsigned integer 00567 selfTest[5] = rawData[2] & 0x1F ; // ZG_TEST result is a five-bit unsigned integer 00568 // Process results to allow final comparison with factory set values 00569 factoryTrim[0] = (4096.0f*0.34f)*(pow( (0.92f/0.34f) , ((selfTest[0] - 1.0f)/30.0f))); // FT[Xa] factory trim calculation 00570 factoryTrim[1] = (4096.0f*0.34f)*(pow( (0.92f/0.34f) , ((selfTest[1] - 1.0f)/30.0f))); // FT[Ya] factory trim calculation 00571 factoryTrim[2] = (4096.0f*0.34f)*(pow( (0.92f/0.34f) , ((selfTest[2] - 1.0f)/30.0f))); // FT[Za] factory trim calculation 00572 factoryTrim[3] = ( 25.0f*131.0f)*(pow( 1.046f , (selfTest[3] - 1.0f) )); // FT[Xg] factory trim calculation 00573 factoryTrim[4] = (-25.0f*131.0f)*(pow( 1.046f , (selfTest[4] - 1.0f) )); // FT[Yg] factory trim calculation 00574 factoryTrim[5] = ( 25.0f*131.0f)*(pow( 1.046f , (selfTest[5] - 1.0f) )); // FT[Zg] factory trim calculation 00575 00576 // Output self-test results and factory trim calculation if desired 00577 // Serial.println(selfTest[0]); Serial.println(selfTest[1]); Serial.println(selfTest[2]); 00578 // Serial.println(selfTest[3]); Serial.println(selfTest[4]); Serial.println(selfTest[5]); 00579 // Serial.println(factoryTrim[0]); Serial.println(factoryTrim[1]); Serial.println(factoryTrim[2]); 00580 // Serial.println(factoryTrim[3]); Serial.println(factoryTrim[4]); Serial.println(factoryTrim[5]); 00581 00582 // Report results as a ratio of (STR - FT)/FT; the change from Factory Trim of the Self-Test Response 00583 // To get to percent, must multiply by 100 and subtract result from 100 00584 for (int i = 0; i < 6; i++) { 00585 destination[i] = 100.0f + 100.0f*(selfTest[i] - factoryTrim[i])/factoryTrim[i]; // Report percent differences 00586 } 00587 00588 } 00589 00590 00591 00592 // Implementation of Sebastian Madgwick's "...efficient orientation filter for... inertial/magnetic sensor arrays" 00593 // (see http://www.x-io.co.uk/category/open-source/ for examples and more details) 00594 // which fuses acceleration, rotation rate, and magnetic moments to produce a quaternion-based estimate of absolute 00595 // device orientation -- which can be converted to yaw, pitch, and roll. Useful for stabilizing quadcopters, etc. 00596 // The performance of the orientation filter is at least as good as conventional Kalman-based filtering algorithms 00597 // but is much less computationally intensive---it can be performed on a 3.3 V Pro Mini operating at 8 MHz! 00598 void MadgwickQuaternionUpdate(float ax, float ay, float az, float gx, float gy, float gz, float mx, float my, float mz) 00599 { 00600 float q1 = q[0], q2 = q[1], q3 = q[2], q4 = q[3]; // short name local variable for readability 00601 float norm; 00602 float hx, hy, _2bx, _2bz; 00603 float s1, s2, s3, s4; 00604 float qDot1, qDot2, qDot3, qDot4; 00605 00606 // Auxiliary variables to avoid repeated arithmetic 00607 float _2q1mx; 00608 float _2q1my; 00609 float _2q1mz; 00610 float _2q2mx; 00611 float _4bx; 00612 float _4bz; 00613 float _2q1 = 2.0f * q1; 00614 float _2q2 = 2.0f * q2; 00615 float _2q3 = 2.0f * q3; 00616 float _2q4 = 2.0f * q4; 00617 float _2q1q3 = 2.0f * q1 * q3; 00618 float _2q3q4 = 2.0f * q3 * q4; 00619 float q1q1 = q1 * q1; 00620 float q1q2 = q1 * q2; 00621 float q1q3 = q1 * q3; 00622 float q1q4 = q1 * q4; 00623 float q2q2 = q2 * q2; 00624 float q2q3 = q2 * q3; 00625 float q2q4 = q2 * q4; 00626 float q3q3 = q3 * q3; 00627 float q3q4 = q3 * q4; 00628 float q4q4 = q4 * q4; 00629 00630 // Normalise accelerometer measurement 00631 norm = sqrt(ax * ax + ay * ay + az * az); 00632 if (norm == 0.0f) return; // handle NaN 00633 norm = 1.0f/norm; 00634 ax *= norm; 00635 ay *= norm; 00636 az *= norm; 00637 00638 // Normalise magnetometer measurement 00639 norm = sqrt(mx * mx + my * my + mz * mz); 00640 if (norm == 0.0f) return; // handle NaN 00641 norm = 1.0f/norm; 00642 mx *= norm; 00643 my *= norm; 00644 mz *= norm; 00645 00646 // Reference direction of Earth's magnetic field 00647 _2q1mx = 2.0f * q1 * mx; 00648 _2q1my = 2.0f * q1 * my; 00649 _2q1mz = 2.0f * q1 * mz; 00650 _2q2mx = 2.0f * q2 * mx; 00651 hx = mx * q1q1 - _2q1my * q4 + _2q1mz * q3 + mx * q2q2 + _2q2 * my * q3 + _2q2 * mz * q4 - mx * q3q3 - mx * q4q4; 00652 hy = _2q1mx * q4 + my * q1q1 - _2q1mz * q2 + _2q2mx * q3 - my * q2q2 + my * q3q3 + _2q3 * mz * q4 - my * q4q4; 00653 _2bx = sqrt(hx * hx + hy * hy); 00654 _2bz = -_2q1mx * q3 + _2q1my * q2 + mz * q1q1 + _2q2mx * q4 - mz * q2q2 + _2q3 * my * q4 - mz * q3q3 + mz * q4q4; 00655 _4bx = 2.0f * _2bx; 00656 _4bz = 2.0f * _2bz; 00657 00658 // Gradient decent algorithm corrective step 00659 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); 00660 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); 00661 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); 00662 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); 00663 norm = sqrt(s1 * s1 + s2 * s2 + s3 * s3 + s4 * s4); // normalise step magnitude 00664 norm = 1.0f/norm; 00665 s1 *= norm; 00666 s2 *= norm; 00667 s3 *= norm; 00668 s4 *= norm; 00669 00670 // Compute rate of change of quaternion 00671 qDot1 = 0.5f * (-q2 * gx - q3 * gy - q4 * gz) - beta * s1; 00672 qDot2 = 0.5f * (q1 * gx + q3 * gz - q4 * gy) - beta * s2; 00673 qDot3 = 0.5f * (q1 * gy - q2 * gz + q4 * gx) - beta * s3; 00674 qDot4 = 0.5f * (q1 * gz + q2 * gy - q3 * gx) - beta * s4; 00675 00676 // Integrate to yield quaternion 00677 q1 += qDot1 * deltat; 00678 q2 += qDot2 * deltat; 00679 q3 += qDot3 * deltat; 00680 q4 += qDot4 * deltat; 00681 norm = sqrt(q1 * q1 + q2 * q2 + q3 * q3 + q4 * q4); // normalise quaternion 00682 norm = 1.0f/norm; 00683 q[0] = q1 * norm; 00684 q[1] = q2 * norm; 00685 q[2] = q3 * norm; 00686 q[3] = q4 * norm; 00687 00688 } 00689 00690 00691 00692 // Similar to Madgwick scheme but uses proportional and integral filtering on the error between estimated reference vectors and 00693 // measured ones. 00694 void MahonyQuaternionUpdate(float ax, float ay, float az, float gx, float gy, float gz, float mx, float my, float mz) 00695 { 00696 float q1 = q[0], q2 = q[1], q3 = q[2], q4 = q[3]; // short name local variable for readability 00697 float norm; 00698 float hx, hy, bx, bz; 00699 float vx, vy, vz, wx, wy, wz; 00700 float ex, ey, ez; 00701 float pa, pb, pc; 00702 00703 // Auxiliary variables to avoid repeated arithmetic 00704 float q1q1 = q1 * q1; 00705 float q1q2 = q1 * q2; 00706 float q1q3 = q1 * q3; 00707 float q1q4 = q1 * q4; 00708 float q2q2 = q2 * q2; 00709 float q2q3 = q2 * q3; 00710 float q2q4 = q2 * q4; 00711 float q3q3 = q3 * q3; 00712 float q3q4 = q3 * q4; 00713 float q4q4 = q4 * q4; 00714 00715 // Normalise accelerometer measurement 00716 norm = sqrt(ax * ax + ay * ay + az * az); 00717 if (norm == 0.0f) return; // handle NaN 00718 norm = 1.0f / norm; // use reciprocal for division 00719 ax *= norm; 00720 ay *= norm; 00721 az *= norm; 00722 00723 // Normalise magnetometer measurement 00724 norm = sqrt(mx * mx + my * my + mz * mz); 00725 if (norm == 0.0f) return; // handle NaN 00726 norm = 1.0f / norm; // use reciprocal for division 00727 mx *= norm; 00728 my *= norm; 00729 mz *= norm; 00730 00731 // Reference direction of Earth's magnetic field 00732 hx = 2.0f * mx * (0.5f - q3q3 - q4q4) + 2.0f * my * (q2q3 - q1q4) + 2.0f * mz * (q2q4 + q1q3); 00733 hy = 2.0f * mx * (q2q3 + q1q4) + 2.0f * my * (0.5f - q2q2 - q4q4) + 2.0f * mz * (q3q4 - q1q2); 00734 bx = sqrt((hx * hx) + (hy * hy)); 00735 bz = 2.0f * mx * (q2q4 - q1q3) + 2.0f * my * (q3q4 + q1q2) + 2.0f * mz * (0.5f - q2q2 - q3q3); 00736 00737 // Estimated direction of gravity and magnetic field 00738 vx = 2.0f * (q2q4 - q1q3); 00739 vy = 2.0f * (q1q2 + q3q4); 00740 vz = q1q1 - q2q2 - q3q3 + q4q4; 00741 wx = 2.0f * bx * (0.5f - q3q3 - q4q4) + 2.0f * bz * (q2q4 - q1q3); 00742 wy = 2.0f * bx * (q2q3 - q1q4) + 2.0f * bz * (q1q2 + q3q4); 00743 wz = 2.0f * bx * (q1q3 + q2q4) + 2.0f * bz * (0.5f - q2q2 - q3q3); 00744 00745 // Error is cross product between estimated direction and measured direction of gravity 00746 ex = (ay * vz - az * vy) + (my * wz - mz * wy); 00747 ey = (az * vx - ax * vz) + (mz * wx - mx * wz); 00748 ez = (ax * vy - ay * vx) + (mx * wy - my * wx); 00749 if (Ki > 0.0f) 00750 { 00751 eInt[0] += ex; // accumulate integral error 00752 eInt[1] += ey; 00753 eInt[2] += ez; 00754 } 00755 else 00756 { 00757 eInt[0] = 0.0f; // prevent integral wind up 00758 eInt[1] = 0.0f; 00759 eInt[2] = 0.0f; 00760 } 00761 00762 // Apply feedback terms 00763 gx = gx + Kp * ex + Ki * eInt[0]; 00764 gy = gy + Kp * ey + Ki * eInt[1]; 00765 gz = gz + Kp * ez + Ki * eInt[2]; 00766 00767 // Integrate rate of change of quaternion 00768 pa = q2; 00769 pb = q3; 00770 pc = q4; 00771 q1 = q1 + (-q2 * gx - q3 * gy - q4 * gz) * (0.5f * deltat); 00772 q2 = pa + (q1 * gx + pb * gz - pc * gy) * (0.5f * deltat); 00773 q3 = pb + (q1 * gy - pa * gz + pc * gx) * (0.5f * deltat); 00774 q4 = pc + (q1 * gz + pa * gy - pb * gx) * (0.5f * deltat); 00775 00776 // Normalise quaternion 00777 norm = sqrt(q1 * q1 + q2 * q2 + q3 * q3 + q4 * q4); 00778 norm = 1.0f / norm; 00779 q[0] = q1 * norm; 00780 q[1] = q2 * norm; 00781 q[2] = q3 * norm; 00782 q[3] = q4 * norm; 00783 00784 } 00785 }; 00786 #endif
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