航空研究会
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MPU9255_ver3
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MPU9250.cpp
00001 #include "mbed.h" 00002 #include "math.h" 00003 #include "MPU9250.h" 00004 00005 00006 MPU9250::MPU9250(PinName sda, PinName scl, RawSerial* serial_p) 00007 : 00008 i2c_p(new I2C(sda,scl)), 00009 i2c(*i2c_p), 00010 pc_p(serial_p) 00011 { 00012 initializeValue(); 00013 } 00014 00015 MPU9250::~MPU9250(){} 00016 00017 00018 /*---------- public function ----------*/ 00019 bool MPU9250::Initialize(void){ 00020 uint8_t whoami; 00021 00022 i2c.frequency(400000); // use fast (400 kHz) I2C 00023 timer.start(); 00024 00025 whoami = Whoami_MPU9250(); 00026 pc_p->printf("I AM 0x%x\n\r", whoami); pc_p->printf("I SHOULD BE 0x71\n\r"); 00027 00028 if(whoami == IAM_MPU9250){ 00029 resetMPU9250(); // Reset registers to default in preparation for device calibration 00030 calibrateMPU9250(gyroBias, accelBias); // Calibrate gyro and accelerometers, load biases in bias registers 00031 wait(1); 00032 00033 initMPU9250(); 00034 initAK8963(magCalibration); 00035 00036 pc_p->printf("Accelerometer full-scale range = %f g\n\r", 2.0f*(float)(1<<Ascale)); 00037 pc_p->printf("Gyroscope full-scale range = %f deg/s\n\r", 250.0f*(float)(1<<Gscale)); 00038 00039 if(Mscale == 0) pc_p->printf("Magnetometer resolution = 14 bits\n\r"); 00040 if(Mscale == 1) pc_p->printf("Magnetometer resolution = 16 bits\n\r"); 00041 if(Mmode == 2) pc_p->printf("Magnetometer ODR = 8 Hz\n\r"); 00042 if(Mmode == 6) pc_p->printf("Magnetometer ODR = 100 Hz\n\r"); 00043 00044 getAres(); 00045 getGres(); 00046 getMres(); 00047 00048 pc_p->printf("mpu9250 initialized\r\n"); 00049 return true; 00050 }else return false; 00051 } 00052 00053 bool MPU9250::sensingAcGyMg(){ 00054 if(readByte(MPU9250_ADDRESS, INT_STATUS) & 0x01) { // On interrupt, check if data ready interrupt 00055 sensingAccel(); 00056 sensingGyro(); 00057 sensingMag(); 00058 return true; 00059 }else return false; 00060 } 00061 00062 00063 void MPU9250::calculatePostureAngle(float degree[3]){ 00064 Now = timer.read_us(); 00065 deltat = (float)((Now - lastUpdate)/1000000.0f); // set integration time by time elapsed since last filter update 00066 lastUpdate = Now; 00067 00068 // if(lastUpdate - firstUpdate > 10000000.0f) { 00069 // beta = 0.04; // decrease filter gain after stabilized 00070 // zeta = 0.015; // increasey bias drift gain after stabilized 00071 // } 00072 00073 // Pass gyro rate as rad/s 00074 MadgwickQuaternionUpdate(ax, ay, az, gx*PI/180.0f, gy*PI/180.0f, gz*PI/180.0f, my, mx, mz); 00075 MahonyQuaternionUpdate(ax, ay, az, gx*PI/180.0f, gy*PI/180.0f, gz*PI/180.0f, my, mx, mz); //my, mx, mzになってるけどセンサの設置上の都合だろうか 00076 00077 // Define output variables from updated quaternion---these are Tait-Bryan angles, commonly used in aircraft orientation. 00078 // In this coordinate system, the positive z-axis is down toward Earth. 00079 // Yaw is the angle between Sensor x-axis and Earth magnetic North (or true North if corrected for local declination, looking down on the sensor positive yaw is counterclockwise. 00080 // Pitch is angle between sensor x-axis and Earth ground plane, toward the Earth is positive, up toward the sky is negative. 00081 // Roll is angle between sensor y-axis and Earth ground plane, y-axis up is positive roll. 00082 // These arise from the definition of the homogeneous rotation matrix constructed from quaternions. 00083 // Tait-Bryan angles as well as Euler angles are non-commutative; that is, the get the correct orientation the rotations must be 00084 // applied in the correct order which for this configuration is yaw, pitch, and then roll. 00085 // For more see http://en.wikipedia.org/wiki/Conversion_between_quaternions_and_Euler_angles which has additional links. 00086 translateQuaternionToDeg(q); 00087 calibrateDegree(); 00088 degree[0] = roll; 00089 degree[1] = pitch; 00090 degree[2] = yaw; 00091 } 00092 00093 00094 float MPU9250::calculateYawByMg(){ 00095 transformCoordinateFromCompassToMPU(); 00096 lpmag[0] = LPGAIN_MAG *lpmag[0] + (1 - LPGAIN_MAG)*mx; 00097 lpmag[1] = LPGAIN_MAG *lpmag[1] + (1 - LPGAIN_MAG)*my; 00098 lpmag[2] = LPGAIN_MAG *lpmag[2] + (1 - LPGAIN_MAG)*mz; 00099 00100 float radroll = PI/180.0f * roll; 00101 float radpitch = PI/180.0f * pitch; 00102 00103 return 180.0f/PI * atan2(lpmag[2]*sin(radpitch) - lpmag[1]*cos(radpitch), 00104 lpmag[0]*cos(radroll) - lpmag[1]*sin(radroll)*sin(radpitch) + lpmag[2]*sin(radroll)*cos(radpitch)); 00105 } 00106 00107 00108 // Accelerometer and gyroscope self test; check calibration wrt factory settings 00109 void MPU9250::MPU9250SelfTest(float * destination) // Should return percent deviation from factory trim values, +/- 14 or less deviation is a pass 00110 { 00111 uint8_t rawData[6] = {0, 0, 0, 0, 0, 0}; 00112 uint8_t selfTest[6]; 00113 int16_t gAvg[3], aAvg[3], aSTAvg[3], gSTAvg[3]; 00114 float factoryTrim[6]; 00115 uint8_t FS = 0; 00116 00117 writeByte(MPU9250_ADDRESS, SMPLRT_DIV, 0x00); // Set gyro sample rate to 1 kHz 00118 writeByte(MPU9250_ADDRESS, CONFIG, 0x02); // Set gyro sample rate to 1 kHz and DLPF to 92 Hz 00119 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 1<<FS); // Set full scale range for the gyro to 250 dps 00120 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG2, 0x02); // Set accelerometer rate to 1 kHz and bandwidth to 92 Hz 00121 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 1<<FS); // Set full scale range for the accelerometer to 2 g 00122 00123 for( int ii = 0; ii < 200; ii++) { // get average current values of gyro and acclerometer 00124 readBytes(MPU9250_ADDRESS, ACCEL_XOUT_H, 6, &rawData[0]); // Read the six raw data registers into data array 00125 aAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value 00126 aAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; 00127 aAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 00128 00129 readBytes(MPU9250_ADDRESS, GYRO_XOUT_H, 6, &rawData[0]); // Read the six raw data registers sequentially into data array 00130 gAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value 00131 gAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; 00132 gAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 00133 } 00134 00135 for (int ii =0; ii < 3; ii++) { // Get average of 200 values and store as average current readings 00136 aAvg[ii] /= 200; 00137 gAvg[ii] /= 200; 00138 } 00139 00140 // Configure the accelerometer for self-test 00141 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 0xE0); // Enable self test on all three axes and set accelerometer range to +/- 2 g 00142 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 0xE0); // Enable self test on all three axes and set gyro range to +/- 250 degrees/s 00143 //delay(55); // Delay a while to let the device stabilize 00144 00145 for( int ii = 0; ii < 200; ii++) { // get average self-test values of gyro and acclerometer 00146 readBytes(MPU9250_ADDRESS, ACCEL_XOUT_H, 6, &rawData[0]); // Read the six raw data registers into data array 00147 aSTAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value 00148 aSTAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; 00149 aSTAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 00150 00151 readBytes(MPU9250_ADDRESS, GYRO_XOUT_H, 6, &rawData[0]); // Read the six raw data registers sequentially into data array 00152 gSTAvg[0] += (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value 00153 gSTAvg[1] += (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; 00154 gSTAvg[2] += (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 00155 } 00156 00157 for (int ii =0; ii < 3; ii++) { // Get average of 200 values and store as average self-test readings 00158 aSTAvg[ii] /= 200; 00159 gSTAvg[ii] /= 200; 00160 } 00161 00162 // Configure the gyro and accelerometer for normal operation 00163 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 0x00); 00164 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 0x00); 00165 //delay(45); // Delay a while to let the device stabilize 00166 00167 // Retrieve accelerometer and gyro factory Self-Test Code from USR_Reg 00168 selfTest[0] = readByte(MPU9250_ADDRESS, SELF_TEST_X_ACCEL); // X-axis accel self-test results 00169 selfTest[1] = readByte(MPU9250_ADDRESS, SELF_TEST_Y_ACCEL); // Y-axis accel self-test results 00170 selfTest[2] = readByte(MPU9250_ADDRESS, SELF_TEST_Z_ACCEL); // Z-axis accel self-test results 00171 selfTest[3] = readByte(MPU9250_ADDRESS, SELF_TEST_X_GYRO); // X-axis gyro self-test results 00172 selfTest[4] = readByte(MPU9250_ADDRESS, SELF_TEST_Y_GYRO); // Y-axis gyro self-test results 00173 selfTest[5] = readByte(MPU9250_ADDRESS, SELF_TEST_Z_GYRO); // Z-axis gyro self-test results 00174 00175 // Retrieve factory self-test value from self-test code reads 00176 factoryTrim[0] = (float)(2620/1<<FS)*(pow( 1.01 , ((float)selfTest[0] - 1.0) )); // FT[Xa] factory trim calculation 00177 factoryTrim[1] = (float)(2620/1<<FS)*(pow( 1.01 , ((float)selfTest[1] - 1.0) )); // FT[Ya] factory trim calculation 00178 factoryTrim[2] = (float)(2620/1<<FS)*(pow( 1.01 , ((float)selfTest[2] - 1.0) )); // FT[Za] factory trim calculation 00179 factoryTrim[3] = (float)(2620/1<<FS)*(pow( 1.01 , ((float)selfTest[3] - 1.0) )); // FT[Xg] factory trim calculation 00180 factoryTrim[4] = (float)(2620/1<<FS)*(pow( 1.01 , ((float)selfTest[4] - 1.0) )); // FT[Yg] factory trim calculation 00181 factoryTrim[5] = (float)(2620/1<<FS)*(pow( 1.01 , ((float)selfTest[5] - 1.0) )); // FT[Zg] factory trim calculation 00182 00183 // Report results as a ratio of (STR - FT)/FT; the change from Factory Trim of the Self-Test Response 00184 // To get percent, must multiply by 100 00185 for (int i = 0; i < 3; i++) { 00186 destination[i] = 100.0*((float)(aSTAvg[i] - aAvg[i]))/factoryTrim[i]; // Report percent differences 00187 destination[i+3] = 100.0*((float)(gSTAvg[i] - gAvg[i]))/factoryTrim[i+3]; // Report percent differences 00188 } 00189 } 00190 00191 void MPU9250::pickupAccel(float accel[3]){ 00192 sensingAccel(); 00193 accel[0] = ax; 00194 accel[1] = ay; 00195 accel[2] = az; 00196 } 00197 00198 void MPU9250::pickupGyro(float gyro[3]){ 00199 sensingGyro(); 00200 gyro[0] = gx; 00201 gyro[1] = gy; 00202 gyro[2] = gz; 00203 } 00204 00205 void MPU9250::pickupMag(float mag[3]){ 00206 sensingMag(); 00207 mag[0] = mx; 00208 mag[1] = my; 00209 mag[2] = mz; 00210 } 00211 00212 float MPU9250::pickupTemp(void){ 00213 sensingTemp(); 00214 return temperature; 00215 } 00216 00217 void MPU9250::displayAccel(void){ 00218 pc_p->printf("ax = %f", 1000*ax); 00219 pc_p->printf(" ay = %f", 1000*ay); 00220 pc_p->printf(" az = %f mg\n\r", 1000*az); 00221 } 00222 00223 void MPU9250::displayGyro(void){ 00224 pc_p->printf("gx = %f", gx); 00225 pc_p->printf(" gy = %f", gy); 00226 pc_p->printf(" gz = %f deg/s\n\r", gz); 00227 } 00228 00229 void MPU9250::displayMag(void){ 00230 pc_p->printf("mx = %f,", mx); 00231 pc_p->printf(" my = %f,", my); 00232 pc_p->printf(" mz = %f mG\n\r", mz); 00233 } 00234 00235 void MPU9250::displayQuaternion(void){ 00236 pc_p->printf("q0 = %f\n\r", q[0]); 00237 pc_p->printf("q1 = %f\n\r", q[1]); 00238 pc_p->printf("q2 = %f\n\r", q[2]); 00239 pc_p->printf("q3 = %f\n\r", q[3]); 00240 } 00241 00242 void MPU9250::displayAngle(void){ 00243 //pc_p->printf("$%d %d %d;",(int)(yaw*100),(int)(pitch*100),(int)(roll*100)); 00244 pc_p->printf("Roll: %f\tPitch: %f\tYaw: %f\n\r", roll, pitch, yaw); 00245 } 00246 00247 void MPU9250::displayTemperature(void){ 00248 pc_p->printf(" temperature = %f C\n\r", temperature); 00249 } 00250 00251 void MPU9250::setMagBias(float bias_x, float bias_y, float bias_z){ 00252 magbias[0] = bias_x; 00253 magbias[1] = bias_y; 00254 magbias[2] = bias_z; 00255 } 00256 00257 /*---------- private function ----------*/ 00258 00259 void MPU9250::writeByte(uint8_t address, uint8_t subAddress, uint8_t data) 00260 { 00261 char data_write[2]; 00262 00263 data_write[0] = subAddress; 00264 data_write[1] = data; 00265 i2c.write(address, data_write, 2, 0); 00266 } 00267 00268 char MPU9250::readByte(uint8_t address, uint8_t subAddress) 00269 { 00270 char data[1]; // `data` will store the register data 00271 char data_write[1]; 00272 00273 data_write[0] = subAddress; 00274 i2c.write(address, data_write, 1, 1); // no stop 00275 i2c.read(address, data, 1, 0); 00276 return data[0]; 00277 } 00278 00279 void MPU9250::readBytes(uint8_t address, uint8_t subAddress, uint8_t count, uint8_t * dest) 00280 { 00281 char data[14]; 00282 char data_write[1]; 00283 00284 data_write[0] = subAddress; 00285 i2c.write(address, data_write, 1, 1); // no stop 00286 i2c.read(address, data, count, 0); 00287 for(int ii = 0; ii < count; ii++) { 00288 dest[ii] = data[ii]; 00289 } 00290 } 00291 00292 void MPU9250::initializeValue(void){ 00293 Ascale = AFS_2G; // AFS_2G, AFS_4G, AFS_8G, AFS_16G 00294 Gscale = GFS_250DPS; // GFS_250DPS, GFS_500DPS, GFS_1000DPS, GFS_2000DPS 00295 Mscale = MFS_16BITS; // MFS_14BITS or MFS_16BITS, 14-bit or 16-bit magnetometer resolution 00296 Mmode = 0x06; // Either 8 Hz 0x02) or 100 Hz (0x06) magnetometer data ODR 00297 00298 GyroMeasError = PI * (60.0f / 180.0f); 00299 beta = sqrt(3.0f / 4.0f) * GyroMeasError; // compute beta 00300 GyroMeasDrift = PI * (1.0f / 180.0f); // gyroscope measurement drift in rad/s/s (start at 0.0 deg/s/s) 00301 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 00302 00303 deltat = 0.0f; // integration interval for both filter schemes 00304 lastUpdate = 0, firstUpdate = 0, Now = 0; // used to calculate integration interval // used to calculate integration interval 00305 00306 for(int i=0; i<3; i++){ 00307 magCalibration[i] = 0; 00308 gyroBias[i] = 0; 00309 accelBias[i] = 0; 00310 magbias[i] = 0; 00311 00312 eInt[i] = 0.0f; 00313 00314 lpmag[i] = 0.0f; 00315 } 00316 00317 q[0] = 1.0f; 00318 q[1] = 0.0f; 00319 q[2] = 0.0f; 00320 q[3] = 0.0f; 00321 } 00322 00323 void MPU9250::initMPU9250(void) 00324 { 00325 // Initialize MPU9250 device 00326 // wake up device 00327 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x00); // Clear sleep mode bit (6), enable all sensors 00328 wait(0.1); // Delay 100 ms for PLL to get established on x-axis gyro; should check for PLL ready interrupt 00329 00330 // get stable time source 00331 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x01); // Set clock source to be PLL with x-axis gyroscope reference, bits 2:0 = 001 00332 00333 // Configure Gyro and Accelerometer 00334 // Disable FSYNC and set accelerometer and gyro bandwidth to 44 and 42 Hz, respectively; 00335 // DLPF_CFG = bits 2:0 = 010; this sets the sample rate at 1 kHz for both 00336 // Maximum delay is 4.9 ms which is just over a 200 Hz maximum rate 00337 writeByte(MPU9250_ADDRESS, CONFIG, 0x03); 00338 00339 // Set sample rate = gyroscope output rate/(1 + SMPLRT_DIV) 00340 writeByte(MPU9250_ADDRESS, SMPLRT_DIV, 0x04); // Use a 200 Hz rate; the same rate set in CONFIG above 00341 00342 // Set gyroscope full scale range 00343 // Range selects FS_SEL and AFS_SEL are 0 - 3, so 2-bit values are left-shifted into positions 4:3 00344 uint8_t c = readByte(MPU9250_ADDRESS, GYRO_CONFIG); // get current GYRO_CONFIG register value 00345 // c = c & ~0xE0; // Clear self-test bits [7:5] 00346 c = c & ~0x02; // Clear Fchoice bits [1:0] 00347 c = c & ~0x18; // Clear AFS bits [4:3] 00348 c = c | Gscale << 3; // Set full scale range for the gyro 00349 // c =| 0x00; // Set Fchoice for the gyro to 11 by writing its inverse to bits 1:0 of GYRO_CONFIG 00350 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, c ); // Write new GYRO_CONFIG value to register 00351 00352 // Set accelerometer full-scale range configuration 00353 c = readByte(MPU9250_ADDRESS, ACCEL_CONFIG); // get current ACCEL_CONFIG register value 00354 // c = c & ~0xE0; // Clear self-test bits [7:5] 00355 c = c & ~0x18; // Clear AFS bits [4:3] 00356 c = c | Ascale << 3; // Set full scale range for the accelerometer 00357 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, c); // Write new ACCEL_CONFIG register value 00358 00359 // Set accelerometer sample rate configuration 00360 // It is possible to get a 4 kHz sample rate from the accelerometer by choosing 1 for 00361 // accel_fchoice_b bit [3]; in this case the bandwidth is 1.13 kHz 00362 c = readByte(MPU9250_ADDRESS, ACCEL_CONFIG2); // get current ACCEL_CONFIG2 register value 00363 c = c & ~0x0F; // Clear accel_fchoice_b (bit 3) and A_DLPFG (bits [2:0]) 00364 c = c | 0x03; // Set accelerometer rate to 1 kHz and bandwidth to 41 Hz 00365 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG2, c); // Write new ACCEL_CONFIG2 register value 00366 00367 // The accelerometer, gyro, and thermometer are set to 1 kHz sample rates, 00368 // but all these rates are further reduced by a factor of 5 to 200 Hz because of the SMPLRT_DIV setting 00369 00370 // Configure Interrupts and Bypass Enable 00371 // Set interrupt pin active high, push-pull, and clear on read of INT_STATUS, enable I2C_BYPASS_EN so additional chips 00372 // can join the I2C bus and all can be controlled by the Arduino as master 00373 writeByte(MPU9250_ADDRESS, INT_PIN_CFG, 0x22); 00374 writeByte(MPU9250_ADDRESS, INT_ENABLE, 0x01); // Enable data ready (bit 0) interrupt 00375 } 00376 00377 void MPU9250::initAK8963(float * destination) 00378 { 00379 // First extract the factory calibration for each magnetometer axis 00380 uint8_t rawData[3]; // x/y/z gyro calibration data stored here 00381 00382 writeByte(AK8963_ADDRESS, AK8963_CNTL, 0x00); // Power down magnetometer 00383 wait(0.01); 00384 00385 writeByte(AK8963_ADDRESS, AK8963_CNTL, 0x0F); // Enter Fuse ROM access mode 00386 wait(0.01); 00387 00388 readBytes(AK8963_ADDRESS, AK8963_ASAX, 3, &rawData[0]); // Read the x-, y-, and z-axis calibration values 00389 destination[0] = (float)(rawData[0] - 128)/256.0f + 1.0f; // Return x-axis sensitivity adjustment values, etc. 00390 destination[1] = (float)(rawData[1] - 128)/256.0f + 1.0f; 00391 destination[2] = (float)(rawData[2] - 128)/256.0f + 1.0f; 00392 writeByte(AK8963_ADDRESS, AK8963_CNTL, 0x00); // Power down magnetometer 00393 wait(0.01); 00394 00395 // Configure the magnetometer for continuous read and highest resolution 00396 // set Mscale bit 4 to 1 (0) to enable 16 (14) bit resolution in CNTL register, 00397 // and enable continuous mode data acquisition Mmode (bits [3:0]), 0010 for 8 Hz and 0110 for 100 Hz sample rates 00398 writeByte(AK8963_ADDRESS, AK8963_CNTL, Mscale << 4 | Mmode); // Set magnetometer data resolution and sample ODR 00399 wait(0.01); 00400 } 00401 00402 void MPU9250::resetMPU9250(void) 00403 { 00404 // reset device 00405 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x80); // Write a one to bit 7 reset bit; toggle reset device 00406 wait(0.1); 00407 } 00408 00409 // Function which accumulates gyro and accelerometer data after device initialization. It calculates the average 00410 // of the at-rest readings and then loads the resulting offsets into accelerometer and gyro bias registers. 00411 void MPU9250::calibrateMPU9250(float * dest1, float * dest2) 00412 { 00413 uint8_t data[12]; // data array to hold accelerometer and gyro x, y, z, data 00414 uint16_t ii, packet_count, fifo_count; 00415 int32_t gyro_bias[3] = {0, 0, 0}, accel_bias[3] = {0, 0, 0}; 00416 int32_t accel_bias_reg[3] = {0, 0, 0}; // A place to hold the factory accelerometer trim biases 00417 00418 // reset device, reset all registers, clear gyro and accelerometer bias registers 00419 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x80); // Write a one to bit 7 reset bit; toggle reset device 00420 wait(0.1); 00421 00422 // get stable time source 00423 // Set clock source to be PLL with x-axis gyroscope reference, bits 2:0 = 001 00424 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x01); 00425 writeByte(MPU9250_ADDRESS, PWR_MGMT_2, 0x00); 00426 wait(0.2); 00427 00428 // Configure device for bias calculation 00429 writeByte(MPU9250_ADDRESS, INT_ENABLE, 0x00); // Disable all interrupts 00430 writeByte(MPU9250_ADDRESS, FIFO_EN, 0x00); // Disable FIFO 00431 writeByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x00); // Turn on internal clock source 00432 writeByte(MPU9250_ADDRESS, I2C_MST_CTRL, 0x00); // Disable I2C master 00433 writeByte(MPU9250_ADDRESS, USER_CTRL, 0x00); // Disable FIFO and I2C master modes 00434 writeByte(MPU9250_ADDRESS, USER_CTRL, 0x0C); // Reset FIFO and DMP 00435 wait(0.015); 00436 00437 // Configure MPU9250 gyro and accelerometer for bias calculation 00438 writeByte(MPU9250_ADDRESS, CONFIG, 0x01); // Set low-pass filter to 188 Hz 00439 writeByte(MPU9250_ADDRESS, SMPLRT_DIV, 0x00); // Set sample rate to 1 kHz 00440 writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 0x00); // Set gyro full-scale to 250 degrees per second, maximum sensitivity 00441 writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 0x00); // Set accelerometer full-scale to 2 g, maximum sensitivity 00442 00443 uint16_t gyrosensitivity = 131; // = 131 LSB/degrees/sec 00444 uint16_t accelsensitivity = 16384; // = 16384 LSB/g 00445 00446 // Configure FIFO to capture accelerometer and gyro data for bias calculation 00447 writeByte(MPU9250_ADDRESS, USER_CTRL, 0x40); // Enable FIFO 00448 writeByte(MPU9250_ADDRESS, FIFO_EN, 0x78); // Enable gyro and accelerometer sensors for FIFO (max size 512 bytes in MPU-9250) 00449 wait(0.04); // accumulate 40 samples in 80 milliseconds = 480 bytes 00450 00451 // At end of sample accumulation, turn off FIFO sensor read 00452 writeByte(MPU9250_ADDRESS, FIFO_EN, 0x00); // Disable gyro and accelerometer sensors for FIFO 00453 readBytes(MPU9250_ADDRESS, FIFO_COUNTH, 2, &data[0]); // read FIFO sample count 00454 fifo_count = ((uint16_t)data[0] << 8) | data[1]; 00455 packet_count = fifo_count/12;// How many sets of full gyro and accelerometer data for averaging 00456 00457 for (ii = 0; ii < packet_count; ii++) { 00458 int16_t accel_temp[3] = {0, 0, 0}, gyro_temp[3] = {0, 0, 0}; 00459 readBytes(MPU9250_ADDRESS, FIFO_R_W, 12, &data[0]); // read data for averaging 00460 accel_temp[0] = (int16_t) (((int16_t)data[0] << 8) | data[1] ) ; // Form signed 16-bit integer for each sample in FIFO 00461 accel_temp[1] = (int16_t) (((int16_t)data[2] << 8) | data[3] ) ; 00462 accel_temp[2] = (int16_t) (((int16_t)data[4] << 8) | data[5] ) ; 00463 gyro_temp[0] = (int16_t) (((int16_t)data[6] << 8) | data[7] ) ; 00464 gyro_temp[1] = (int16_t) (((int16_t)data[8] << 8) | data[9] ) ; 00465 gyro_temp[2] = (int16_t) (((int16_t)data[10] << 8) | data[11]) ; 00466 00467 accel_bias[0] += (int32_t) accel_temp[0]; // Sum individual signed 16-bit biases to get accumulated signed 32-bit biases 00468 accel_bias[1] += (int32_t) accel_temp[1]; 00469 accel_bias[2] += (int32_t) accel_temp[2]; 00470 gyro_bias[0] += (int32_t) gyro_temp[0]; 00471 gyro_bias[1] += (int32_t) gyro_temp[1]; 00472 gyro_bias[2] += (int32_t) gyro_temp[2]; 00473 00474 } 00475 accel_bias[0] /= (int32_t) packet_count; // Normalize sums to get average count biases 00476 accel_bias[1] /= (int32_t) packet_count; 00477 accel_bias[2] /= (int32_t) packet_count; 00478 gyro_bias[0] /= (int32_t) packet_count; 00479 gyro_bias[1] /= (int32_t) packet_count; 00480 gyro_bias[2] /= (int32_t) packet_count; 00481 00482 if(accel_bias[2] > 0L) {accel_bias[2] -= (int32_t) accelsensitivity;} // Remove gravity from the z-axis accelerometer bias calculation 00483 else {accel_bias[2] += (int32_t) accelsensitivity;} 00484 00485 // Construct the gyro biases for push to the hardware gyro bias registers, which are reset to zero upon device startup 00486 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 00487 data[1] = (-gyro_bias[0]/4) & 0xFF; // Biases are additive, so change sign on calculated average gyro biases 00488 data[2] = (-gyro_bias[1]/4 >> 8) & 0xFF; 00489 data[3] = (-gyro_bias[1]/4) & 0xFF; 00490 data[4] = (-gyro_bias[2]/4 >> 8) & 0xFF; 00491 data[5] = (-gyro_bias[2]/4) & 0xFF; 00492 00493 /// Push gyro biases to hardware registers 00494 /* 00495 writeByte(MPU9250_ADDRESS, XG_OFFSET_H, data[0]); 00496 writeByte(MPU9250_ADDRESS, XG_OFFSET_L, data[1]); 00497 writeByte(MPU9250_ADDRESS, YG_OFFSET_H, data[2]); 00498 writeByte(MPU9250_ADDRESS, YG_OFFSET_L, data[3]); 00499 writeByte(MPU9250_ADDRESS, ZG_OFFSET_H, data[4]); 00500 writeByte(MPU9250_ADDRESS, ZG_OFFSET_L, data[5]); 00501 */ 00502 dest1[0] = (float) gyro_bias[0]/(float) gyrosensitivity; // construct gyro bias in deg/s for later manual subtraction 00503 dest1[1] = (float) gyro_bias[1]/(float) gyrosensitivity; 00504 dest1[2] = (float) gyro_bias[2]/(float) gyrosensitivity; 00505 00506 // Construct the accelerometer biases for push to the hardware accelerometer bias registers. These registers contain 00507 // factory trim values which must be added to the calculated accelerometer biases; on boot up these registers will hold 00508 // non-zero values. In addition, bit 0 of the lower byte must be preserved since it is used for temperature 00509 // compensation calculations. Accelerometer bias registers expect bias input as 2048 LSB per g, so that 00510 // the accelerometer biases calculated above must be divided by 8. 00511 00512 readBytes(MPU9250_ADDRESS, XA_OFFSET_H, 2, &data[0]); // Read factory accelerometer trim values 00513 accel_bias_reg[0] = (int16_t) ((int16_t)data[0] << 8) | data[1]; 00514 readBytes(MPU9250_ADDRESS, YA_OFFSET_H, 2, &data[0]); 00515 accel_bias_reg[1] = (int16_t) ((int16_t)data[0] << 8) | data[1]; 00516 readBytes(MPU9250_ADDRESS, ZA_OFFSET_H, 2, &data[0]); 00517 accel_bias_reg[2] = (int16_t) ((int16_t)data[0] << 8) | data[1]; 00518 00519 uint32_t mask = 1uL; // Define mask for temperature compensation bit 0 of lower byte of accelerometer bias registers 00520 uint8_t mask_bit[3] = {0, 0, 0}; // Define array to hold mask bit for each accelerometer bias axis 00521 00522 for(ii = 0; ii < 3; ii++) { 00523 if(accel_bias_reg[ii] & mask) mask_bit[ii] = 0x01; // If temperature compensation bit is set, record that fact in mask_bit 00524 } 00525 00526 // Construct total accelerometer bias, including calculated average accelerometer bias from above 00527 accel_bias_reg[0] -= (accel_bias[0]/8); // Subtract calculated averaged accelerometer bias scaled to 2048 LSB/g (16 g full scale) 00528 accel_bias_reg[1] -= (accel_bias[1]/8); 00529 accel_bias_reg[2] -= (accel_bias[2]/8); 00530 00531 data[0] = (accel_bias_reg[0] >> 8) & 0xFF; 00532 data[1] = (accel_bias_reg[0]) & 0xFF; 00533 data[1] = data[1] | mask_bit[0]; // preserve temperature compensation bit when writing back to accelerometer bias registers 00534 data[2] = (accel_bias_reg[1] >> 8) & 0xFF; 00535 data[3] = (accel_bias_reg[1]) & 0xFF; 00536 data[3] = data[3] | mask_bit[1]; // preserve temperature compensation bit when writing back to accelerometer bias registers 00537 data[4] = (accel_bias_reg[2] >> 8) & 0xFF; 00538 data[5] = (accel_bias_reg[2]) & 0xFF; 00539 data[5] = data[5] | mask_bit[2]; // preserve temperature compensation bit when writing back to accelerometer bias registers 00540 00541 // Apparently this is not working for the acceleration biases in the MPU-9250 00542 // Are we handling the temperature correction bit properly? 00543 // Push accelerometer biases to hardware registers 00544 /* 00545 writeByte(MPU9250_ADDRESS, XA_OFFSET_H, data[0]); 00546 writeByte(MPU9250_ADDRESS, XA_OFFSET_L, data[1]); 00547 writeByte(MPU9250_ADDRESS, YA_OFFSET_H, data[2]); 00548 writeByte(MPU9250_ADDRESS, YA_OFFSET_L, data[3]); 00549 writeByte(MPU9250_ADDRESS, ZA_OFFSET_H, data[4]); 00550 writeByte(MPU9250_ADDRESS, ZA_OFFSET_L, data[5]); 00551 */ 00552 // Output scaled accelerometer biases for manual subtraction in the main program 00553 dest2[0] = (float)accel_bias[0]/(float)accelsensitivity; 00554 dest2[1] = (float)accel_bias[1]/(float)accelsensitivity; 00555 dest2[2] = (float)accel_bias[2]/(float)accelsensitivity; 00556 } 00557 00558 void MPU9250::getMres(void) 00559 { 00560 switch (Mscale) 00561 { 00562 // Possible magnetometer scales (and their register bit settings) are: 00563 // 14 bit resolution (0) and 16 bit resolution (1) 00564 case MFS_14BITS: 00565 mRes = 10.0*4219.0/8190.0; // Proper scale to return milliGauss 00566 break; 00567 case MFS_16BITS: 00568 mRes = 10.0*4219.0/32760.0; // Proper scale to return milliGauss 00569 break; 00570 } 00571 } 00572 00573 void MPU9250::getGres(void) { 00574 switch (Gscale) 00575 { 00576 // Possible gyro scales (and their register bit settings) are: 00577 // 250 DPS (00), 500 DPS (01), 1000 DPS (10), and 2000 DPS (11). 00578 // Here's a bit of an algorith to calculate DPS/(ADC tick) based on that 2-bit value: 00579 case GFS_250DPS: 00580 gRes = 250.0/32768.0; 00581 break; 00582 case GFS_500DPS: 00583 gRes = 500.0/32768.0; 00584 break; 00585 case GFS_1000DPS: 00586 gRes = 1000.0/32768.0; 00587 break; 00588 case GFS_2000DPS: 00589 gRes = 2000.0/32768.0; 00590 break; 00591 } 00592 } 00593 00594 00595 void MPU9250::getAres(void) 00596 { 00597 switch (Ascale) 00598 { 00599 // Possible accelerometer scales (and their register bit settings) are: 00600 // 2 Gs (00), 4 Gs (01), 8 Gs (10), and 16 Gs (11). 00601 // Here's a bit of an algorith to calculate DPS/(ADC tick) based on that 2-bit value: 00602 case AFS_2G: 00603 aRes = 2.0/32768.0; 00604 break; 00605 case AFS_4G: 00606 aRes = 4.0/32768.0; 00607 break; 00608 case AFS_8G: 00609 aRes = 8.0/32768.0; 00610 break; 00611 case AFS_16G: 00612 aRes = 16.0/32768.0; 00613 break; 00614 } 00615 } 00616 00617 void MPU9250::readAccelData(int16_t * destination) 00618 { 00619 uint8_t rawData[6]; // x/y/z accel register data stored here 00620 00621 readBytes(MPU9250_ADDRESS, ACCEL_XOUT_H, 6, &rawData[0]); // Read the six raw data registers into data array 00622 destination[0] = (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value 00623 destination[1] = (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; 00624 destination[2] = (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 00625 } 00626 00627 void MPU9250::readGyroData(int16_t * destination) 00628 { 00629 uint8_t rawData[6]; // x/y/z gyro register data stored here 00630 00631 readBytes(MPU9250_ADDRESS, GYRO_XOUT_H, 6, &rawData[0]); // Read the six raw data registers sequentially into data array 00632 destination[0] = (int16_t)(((int16_t)rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value 00633 destination[1] = (int16_t)(((int16_t)rawData[2] << 8) | rawData[3]) ; 00634 destination[2] = (int16_t)(((int16_t)rawData[4] << 8) | rawData[5]) ; 00635 } 00636 00637 void MPU9250::readMagData(int16_t * destination) 00638 { 00639 uint8_t rawData[7]; // x/y/z gyro register data, ST2 register stored here, must read ST2 at end of data acquisition 00640 00641 if(readByte(AK8963_ADDRESS, AK8963_ST1) & 0x01) { // wait for magnetometer data ready bit to be set 00642 readBytes(AK8963_ADDRESS, AK8963_XOUT_L, 7, &rawData[0]); // Read the six raw data and ST2 registers sequentially into data array 00643 uint8_t c = rawData[6]; // End data read by reading ST2 register 00644 if(!(c & 0x08)) { // Check if magnetic sensor overflow set, if not then report data 00645 destination[0] = (int16_t)(((int16_t)rawData[1] << 8) | rawData[0]); // Turn the MSB and LSB into a signed 16-bit value 00646 destination[1] = (int16_t)(((int16_t)rawData[3] << 8) | rawData[2]) ; // Data stored as little Endian 00647 destination[2] = (int16_t)(((int16_t)rawData[5] << 8) | rawData[4]) ; 00648 } 00649 } 00650 } 00651 00652 int16_t MPU9250::readTempData(void) 00653 { 00654 uint8_t rawData[2]; // x/y/z gyro register data stored here 00655 00656 readBytes(MPU9250_ADDRESS, TEMP_OUT_H, 2, &rawData[0]); // Read the two raw data registers sequentially into data array 00657 00658 return (int16_t)(((int16_t)rawData[0]) << 8 | rawData[1]) ; // Turn the MSB and LSB into a 16-bit value 00659 } 00660 00661 uint8_t MPU9250::Whoami_MPU9250(void){ 00662 return readByte(MPU9250_ADDRESS, WHO_AM_I_MPU9250); 00663 } 00664 00665 uint8_t MPU9250::Whoami_AK8963(void){ 00666 return readByte(WHO_AM_I_AK8963, WHO_AM_I_AK8963); 00667 } 00668 00669 void MPU9250::sensingAccel(void){ 00670 readAccelData(accelCount); 00671 ax = (float)accelCount[0]*aRes - accelBias[0]; 00672 ay = (float)accelCount[1]*aRes - accelBias[1]; 00673 az = (float)accelCount[2]*aRes - accelBias[2]; 00674 } 00675 00676 void MPU9250::sensingGyro(void){ 00677 readGyroData(gyroCount); 00678 gx = (float)gyroCount[0]*gRes - gyroBias[0]; 00679 gy = (float)gyroCount[1]*gRes - gyroBias[1]; 00680 gz = (float)gyroCount[2]*gRes - gyroBias[2]; 00681 } 00682 00683 void MPU9250::sensingMag(void){ 00684 readMagData(magCount); 00685 mx = (float)magCount[0]*mRes*magCalibration[0] - magbias[0]; 00686 my = (float)magCount[1]*mRes*magCalibration[1] - magbias[1]; 00687 mz = (float)magCount[2]*mRes*magCalibration[2] - magbias[2]; 00688 } 00689 00690 void MPU9250::sensingTemp(void){ 00691 tempCount = readTempData(); 00692 temperature = ((float) tempCount) / 333.87f + 21.0f; // Temperature in degrees Centigrade 00693 } 00694 00695 // Implementation of Sebastian Madgwick's "...efficient orientation filter for... inertial/magnetic sensor arrays" 00696 // (see http://www.x-io.co.uk/category/open-source/ for examples and more details) 00697 // which fuses acceleration, rotation rate, and magnetic moments to produce a quaternion-based estimate of absolute 00698 // device orientation -- which can be converted to yaw, pitch, and roll. Useful for stabilizing quadcopters, etc. 00699 // The performance of the orientation filter is at least as good as conventional Kalman-based filtering algorithms 00700 // but is much less computationally intensive---it can be performed on a 3.3 V Pro Mini operating at 8 MHz! 00701 void MPU9250::MadgwickQuaternionUpdate(float ax, float ay, float az, float gx, float gy, float gz, float mx, float my, float mz) 00702 { 00703 float q1 = q[0], q2 = q[1], q3 = q[2], q4 = q[3]; // short name local variable for readability 00704 float norm; 00705 float hx, hy, _2bx, _2bz; 00706 float s1, s2, s3, s4; 00707 float qDot1, qDot2, qDot3, qDot4; 00708 00709 // Auxiliary variables to avoid repeated arithmetic 00710 float _2q1mx; 00711 float _2q1my; 00712 float _2q1mz; 00713 float _2q2mx; 00714 float _4bx; 00715 float _4bz; 00716 float _2q1 = 2.0f * q1; 00717 float _2q2 = 2.0f * q2; 00718 float _2q3 = 2.0f * q3; 00719 float _2q4 = 2.0f * q4; 00720 float _2q1q3 = 2.0f * q1 * q3; 00721 float _2q3q4 = 2.0f * q3 * q4; 00722 float q1q1 = q1 * q1; 00723 float q1q2 = q1 * q2; 00724 float q1q3 = q1 * q3; 00725 float q1q4 = q1 * q4; 00726 float q2q2 = q2 * q2; 00727 float q2q3 = q2 * q3; 00728 float q2q4 = q2 * q4; 00729 float q3q3 = q3 * q3; 00730 float q3q4 = q3 * q4; 00731 float q4q4 = q4 * q4; 00732 00733 // Normalise accelerometer measurement 00734 norm = sqrt(ax * ax + ay * ay + az * az); 00735 if (norm == 0.0f) return; // handle NaN 00736 norm = 1.0f/norm; 00737 ax *= norm; 00738 ay *= norm; 00739 az *= norm; 00740 00741 // Normalise magnetometer measurement 00742 norm = sqrt(mx * mx + my * my + mz * mz); 00743 if (norm == 0.0f) return; // handle NaN 00744 norm = 1.0f/norm; 00745 mx *= norm; 00746 my *= norm; 00747 mz *= norm; 00748 00749 // Reference direction of Earth's magnetic field 00750 _2q1mx = 2.0f * q1 * mx; 00751 _2q1my = 2.0f * q1 * my; 00752 _2q1mz = 2.0f * q1 * mz; 00753 _2q2mx = 2.0f * q2 * mx; 00754 hx = mx * q1q1 - _2q1my * q4 + _2q1mz * q3 + mx * q2q2 + _2q2 * my * q3 + _2q2 * mz * q4 - mx * q3q3 - mx * q4q4; 00755 hy = _2q1mx * q4 + my * q1q1 - _2q1mz * q2 + _2q2mx * q3 - my * q2q2 + my * q3q3 + _2q3 * mz * q4 - my * q4q4; 00756 _2bx = sqrt(hx * hx + hy * hy); 00757 _2bz = -_2q1mx * q3 + _2q1my * q2 + mz * q1q1 + _2q2mx * q4 - mz * q2q2 + _2q3 * my * q4 - mz * q3q3 + mz * q4q4; 00758 _4bx = 2.0f * _2bx; 00759 _4bz = 2.0f * _2bz; 00760 00761 // Gradient decent algorithm corrective step 00762 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); 00763 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); 00764 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); 00765 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); 00766 norm = sqrt(s1 * s1 + s2 * s2 + s3 * s3 + s4 * s4); // normalise step magnitude 00767 norm = 1.0f/norm; 00768 s1 *= norm; 00769 s2 *= norm; 00770 s3 *= norm; 00771 s4 *= norm; 00772 00773 // Compute rate of change of quaternion 00774 qDot1 = 0.5f * (-q2 * gx - q3 * gy - q4 * gz) - beta * s1; 00775 qDot2 = 0.5f * (q1 * gx + q3 * gz - q4 * gy) - beta * s2; 00776 qDot3 = 0.5f * (q1 * gy - q2 * gz + q4 * gx) - beta * s3; 00777 qDot4 = 0.5f * (q1 * gz + q2 * gy - q3 * gx) - beta * s4; 00778 00779 // Integrate to yield quaternion 00780 q1 += qDot1 * deltat; 00781 q2 += qDot2 * deltat; 00782 q3 += qDot3 * deltat; 00783 q4 += qDot4 * deltat; 00784 norm = sqrt(q1 * q1 + q2 * q2 + q3 * q3 + q4 * q4); // normalise quaternion 00785 norm = 1.0f/norm; 00786 q[0] = q1 * norm; 00787 q[1] = q2 * norm; 00788 q[2] = q3 * norm; 00789 q[3] = q4 * norm; 00790 00791 } 00792 00793 void MPU9250::MahonyQuaternionUpdate(float ax, float ay, float az, float gx, float gy, float gz, float mx, float my, float mz) 00794 { 00795 float q1 = q[0], q2 = q[1], q3 = q[2], q4 = q[3]; // short name local variable for readability 00796 float norm; 00797 float hx, hy, bx, bz; 00798 float vx, vy, vz, wx, wy, wz; 00799 float ex, ey, ez; 00800 float pa, pb, pc; 00801 00802 // Auxiliary variables to avoid repeated arithmetic 00803 float q1q1 = q1 * q1; 00804 float q1q2 = q1 * q2; 00805 float q1q3 = q1 * q3; 00806 float q1q4 = q1 * q4; 00807 float q2q2 = q2 * q2; 00808 float q2q3 = q2 * q3; 00809 float q2q4 = q2 * q4; 00810 float q3q3 = q3 * q3; 00811 float q3q4 = q3 * q4; 00812 float q4q4 = q4 * q4; 00813 00814 // Normalise accelerometer measurement 00815 norm = sqrt(ax * ax + ay * ay + az * az); 00816 if (norm == 0.0f) return; // handle NaN 00817 norm = 1.0f / norm; // use reciprocal for division 00818 ax *= norm; 00819 ay *= norm; 00820 az *= norm; 00821 00822 // Normalise magnetometer measurement 00823 norm = sqrt(mx * mx + my * my + mz * mz); 00824 if (norm == 0.0f) return; // handle NaN 00825 norm = 1.0f / norm; // use reciprocal for division 00826 mx *= norm; 00827 my *= norm; 00828 mz *= norm; 00829 00830 // Reference direction of Earth's magnetic field 00831 hx = 2.0f * mx * (0.5f - q3q3 - q4q4) + 2.0f * my * (q2q3 - q1q4) + 2.0f * mz * (q2q4 + q1q3); 00832 hy = 2.0f * mx * (q2q3 + q1q4) + 2.0f * my * (0.5f - q2q2 - q4q4) + 2.0f * mz * (q3q4 - q1q2); 00833 bx = sqrt((hx * hx) + (hy * hy)); 00834 bz = 2.0f * mx * (q2q4 - q1q3) + 2.0f * my * (q3q4 + q1q2) + 2.0f * mz * (0.5f - q2q2 - q3q3); 00835 00836 // Estimated direction of gravity and magnetic field 00837 vx = 2.0f * (q2q4 - q1q3); 00838 vy = 2.0f * (q1q2 + q3q4); 00839 vz = q1q1 - q2q2 - q3q3 + q4q4; 00840 wx = 2.0f * bx * (0.5f - q3q3 - q4q4) + 2.0f * bz * (q2q4 - q1q3); 00841 wy = 2.0f * bx * (q2q3 - q1q4) + 2.0f * bz * (q1q2 + q3q4); 00842 wz = 2.0f * bx * (q1q3 + q2q4) + 2.0f * bz * (0.5f - q2q2 - q3q3); 00843 00844 // Error is cross product between estimated direction and measured direction of gravity 00845 ex = (ay * vz - az * vy) + (my * wz - mz * wy); 00846 ey = (az * vx - ax * vz) + (mz * wx - mx * wz); 00847 ez = (ax * vy - ay * vx) + (mx * wy - my * wx); 00848 if (Ki > 0.0f){ 00849 eInt[0] += ex; // accumulate integral error 00850 eInt[1] += ey; 00851 eInt[2] += ez; 00852 00853 }else{ 00854 eInt[0] = 0.0f; // prevent integral wind up 00855 eInt[1] = 0.0f; 00856 eInt[2] = 0.0f; 00857 } 00858 00859 // Apply feedback terms 00860 gx = gx + Kp * ex + Ki * eInt[0]; 00861 gy = gy + Kp * ey + Ki * eInt[1]; 00862 gz = gz + Kp * ez + Ki * eInt[2]; 00863 00864 // Integrate rate of change of quaternion 00865 pa = q2; 00866 pb = q3; 00867 pc = q4; 00868 q1 = q1 + (-q2 * gx - q3 * gy - q4 * gz) * (0.5f * deltat); 00869 q2 = pa + (q1 * gx + pb * gz - pc * gy) * (0.5f * deltat); 00870 q3 = pb + (q1 * gy - pa * gz + pc * gx) * (0.5f * deltat); 00871 q4 = pc + (q1 * gz + pa * gy - pb * gx) * (0.5f * deltat); 00872 00873 // Normalise quaternion 00874 norm = sqrt(q1 * q1 + q2 * q2 + q3 * q3 + q4 * q4); 00875 norm = 1.0f / norm; 00876 q[0] = q1 * norm; 00877 q[1] = q2 * norm; 00878 q[2] = q3 * norm; 00879 q[3] = q4 * norm; 00880 00881 } 00882 00883 void MPU9250::translateQuaternionToDeg(float quaternion[4]){ 00884 yaw = atan2(2.0f * (quaternion[1] * quaternion[2] + quaternion[0] * quaternion[3]), quaternion[0] * quaternion[0] + quaternion[1] * quaternion[1] - quaternion[2] * quaternion[2] - quaternion[3] * quaternion[3]); 00885 roll = -asin(2.0f * (quaternion[1] * quaternion[3] - quaternion[0] * quaternion[2])); 00886 pitch = atan2(2.0f * (quaternion[0] * quaternion[1] + quaternion[2] * quaternion[3]), quaternion[0] * quaternion[0] - quaternion[1] * quaternion[1] - quaternion[2] * quaternion[2] + quaternion[3] * quaternion[3]); 00887 } 00888 00889 void MPU9250::calibrateDegree(void){ 00890 pitch *= 180.0f / PI; 00891 yaw *= 180.0f / PI; 00892 yaw -= DECLINATION; 00893 roll *= 180.0f / PI; 00894 } 00895 00896 void MPU9250::transformCoordinateFromCompassToMPU(){ 00897 float buf = mx; 00898 mx = my; 00899 my = buf; 00900 mz = -mz; 00901 }
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