Library version of MPU9250AHRS code.
Fork of MPU9250AHRS by
Diff: MPU9250.h
- Revision:
- 4:404c35f32ce3
- Parent:
- 3:c05fbe0aef1f
- Child:
- 5:ea541d293095
--- a/MPU9250.h Thu Sep 04 20:16:36 2014 +0000 +++ b/MPU9250.h Thu Sep 04 21:19:05 2014 +0000 @@ -190,12 +190,12 @@ float aRes, gRes, mRes; // scale resolutions per LSB for the sensors //Set up I2C, (SDA,SCL) -I2C i2c(I2C_SDA, I2C_SCL); +//I2C i2c(I2C_SDA, I2C_SCL); -DigitalOut myled(LED1); +//DigitalOut myled(LED1); // Pin definitions -int intPin = 12; // These can be changed, 2 and 3 are the Arduinos ext int pins +//int intPin = 12; // These can be changed, 2 and 3 are the Arduinos ext int pins int16_t accelCount[3]; // Stores the 16-bit signed accelerometer sensor output int16_t gyroCount[3]; // Stores the 16-bit signed gyro sensor output @@ -216,13 +216,10 @@ float beta = sqrt(3.0f / 4.0f) * GyroMeasError; // compute beta float GyroMeasDrift = PI * (1.0f / 180.0f); // gyroscope measurement drift in rad/s/s (start at 0.0 deg/s/s) 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 -#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 -#define Ki 0.0f float pitch, yaw, roll; float deltat = 0.0f; // integration interval for both filter schemes int lastUpdate = 0, firstUpdate = 0, Now = 0; // used to calculate integration interval // used to calculate integration interval -float q[4] = {1.0f, 0.0f, 0.0f, 0.0f}; // vector to hold quaternion float eInt[3] = {0.0f, 0.0f, 0.0f}; // vector to hold integral error for Mahony method class MPU9250 @@ -235,8 +232,8 @@ //=================================================================================================================== //====== Set of useful function to access acceleratio, gyroscope, and temperature data //=================================================================================================================== - MPU9250(I2C *i2c) _i2c( i2c ) { - break; + MPU9250(I2C *i2c) : _i2c( i2c ) { + } void writeByte(uint8_t address, uint8_t subAddress, uint8_t data) { @@ -619,7 +616,7 @@ // Configure the accelerometer for self-test writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 0xE0); // Enable self test on all three axes and set accelerometer range to +/- 2 g writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 0xE0); // Enable self test on all three axes and set gyro range to +/- 250 degrees/s - delay(25); // Delay a while to let the device stabilize + wait(25); // Delay a while to let the device stabilize for( int ii = 0; ii < 200; ii++) { // get average self-test values of gyro and acclerometer @@ -642,7 +639,7 @@ // Configure the gyro and accelerometer for normal operation writeByte(MPU9250_ADDRESS, ACCEL_CONFIG, 0x00); writeByte(MPU9250_ADDRESS, GYRO_CONFIG, 0x00); - delay(25); // Delay a while to let the device stabilize + wait(25); // Delay a while to let the device stabilize // Retrieve accelerometer and gyro factory Self-Test Code from USR_Reg selfTest[0] = readByte(MPU9250_ADDRESS, SELF_TEST_X_ACCEL); // X-axis accel self-test results @@ -670,195 +667,5 @@ } - -// Implementation of Sebastian Madgwick's "...efficient orientation filter for... inertial/magnetic sensor arrays" -// (see http://www.x-io.co.uk/category/open-source/ for examples and more details) -// which fuses acceleration, rotation rate, and magnetic moments to produce a quaternion-based estimate of absolute -// device orientation -- which can be converted to yaw, pitch, and roll. Useful for stabilizing quadcopters, etc. -// The performance of the orientation filter is at least as good as conventional Kalman-based filtering algorithms -// but is much less computationally intensive---it can be performed on a 3.3 V Pro Mini operating at 8 MHz! - - void MadgwickQuaternionUpdate(float ax, float ay, float az, float gx, float gy, float gz, float mx, float my, float mz) { - float q1 = q[0], q2 = q[1], q3 = q[2], q4 = q[3]; // short name local variable for readability - float norm; - float hx, hy, _2bx, _2bz; - float s1, s2, s3, s4; - float qDot1, qDot2, qDot3, qDot4; - - // Auxiliary variables to avoid repeated arithmetic - float _2q1mx; - float _2q1my; - float _2q1mz; - float _2q2mx; - float _4bx; - float _4bz; - float _2q1 = 2.0f * q1; - float _2q2 = 2.0f * q2; - float _2q3 = 2.0f * q3; - float _2q4 = 2.0f * q4; - float _2q1q3 = 2.0f * q1 * q3; - float _2q3q4 = 2.0f * q3 * q4; - float q1q1 = q1 * q1; - float q1q2 = q1 * q2; - float q1q3 = q1 * q3; - float q1q4 = q1 * q4; - float q2q2 = q2 * q2; - float q2q3 = q2 * q3; - float q2q4 = q2 * q4; - float q3q3 = q3 * q3; - float q3q4 = q3 * q4; - float q4q4 = q4 * q4; - - // Normalise accelerometer measurement - norm = sqrt(ax * ax + ay * ay + az * az); - if (norm == 0.0f) return; // handle NaN - norm = 1.0f/norm; - ax *= norm; - ay *= norm; - az *= norm; - - // Normalise magnetometer measurement - norm = sqrt(mx * mx + my * my + mz * mz); - if (norm == 0.0f) return; // handle NaN - norm = 1.0f/norm; - mx *= norm; - my *= norm; - mz *= norm; - - // Reference direction of Earth's magnetic field - _2q1mx = 2.0f * q1 * mx; - _2q1my = 2.0f * q1 * my; - _2q1mz = 2.0f * q1 * mz; - _2q2mx = 2.0f * q2 * mx; - hx = mx * q1q1 - _2q1my * q4 + _2q1mz * q3 + mx * q2q2 + _2q2 * my * q3 + _2q2 * mz * q4 - mx * q3q3 - mx * q4q4; - hy = _2q1mx * q4 + my * q1q1 - _2q1mz * q2 + _2q2mx * q3 - my * q2q2 + my * q3q3 + _2q3 * mz * q4 - my * q4q4; - _2bx = sqrt(hx * hx + hy * hy); - _2bz = -_2q1mx * q3 + _2q1my * q2 + mz * q1q1 + _2q2mx * q4 - mz * q2q2 + _2q3 * my * q4 - mz * q3q3 + mz * q4q4; - _4bx = 2.0f * _2bx; - _4bz = 2.0f * _2bz; - - // Gradient decent algorithm corrective step - 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); - 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); - 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); - 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); - norm = sqrt(s1 * s1 + s2 * s2 + s3 * s3 + s4 * s4); // normalise step magnitude - norm = 1.0f/norm; - s1 *= norm; - s2 *= norm; - s3 *= norm; - s4 *= norm; - - // Compute rate of change of quaternion - qDot1 = 0.5f * (-q2 * gx - q3 * gy - q4 * gz) - beta * s1; - qDot2 = 0.5f * (q1 * gx + q3 * gz - q4 * gy) - beta * s2; - qDot3 = 0.5f * (q1 * gy - q2 * gz + q4 * gx) - beta * s3; - qDot4 = 0.5f * (q1 * gz + q2 * gy - q3 * gx) - beta * s4; - - // Integrate to yield quaternion - q1 += qDot1 * deltat; - q2 += qDot2 * deltat; - q3 += qDot3 * deltat; - q4 += qDot4 * deltat; - norm = sqrt(q1 * q1 + q2 * q2 + q3 * q3 + q4 * q4); // normalise quaternion - norm = 1.0f/norm; - q[0] = q1 * norm; - q[1] = q2 * norm; - q[2] = q3 * norm; - q[3] = q4 * norm; - -} - - - -// Similar to Madgwick scheme but uses proportional and integral filtering on the error between estimated reference vectors and -// measured ones. - void MahonyQuaternionUpdate(float ax, float ay, float az, float gx, float gy, float gz, float mx, float my, float mz) { - float q1 = q[0], q2 = q[1], q3 = q[2], q4 = q[3]; // short name local variable for readability - float norm; - float hx, hy, bx, bz; - float vx, vy, vz, wx, wy, wz; - float ex, ey, ez; - float pa, pb, pc; - - // Auxiliary variables to avoid repeated arithmetic - float q1q1 = q1 * q1; - float q1q2 = q1 * q2; - float q1q3 = q1 * q3; - float q1q4 = q1 * q4; - float q2q2 = q2 * q2; - float q2q3 = q2 * q3; - float q2q4 = q2 * q4; - float q3q3 = q3 * q3; - float q3q4 = q3 * q4; - float q4q4 = q4 * q4; - - // Normalise accelerometer measurement - norm = sqrt(ax * ax + ay * ay + az * az); - if (norm == 0.0f) return; // handle NaN - norm = 1.0f / norm; // use reciprocal for division - ax *= norm; - ay *= norm; - az *= norm; - - // Normalise magnetometer measurement - norm = sqrt(mx * mx + my * my + mz * mz); - if (norm == 0.0f) return; // handle NaN - norm = 1.0f / norm; // use reciprocal for division - mx *= norm; - my *= norm; - mz *= norm; - - // Reference direction of Earth's magnetic field - hx = 2.0f * mx * (0.5f - q3q3 - q4q4) + 2.0f * my * (q2q3 - q1q4) + 2.0f * mz * (q2q4 + q1q3); - hy = 2.0f * mx * (q2q3 + q1q4) + 2.0f * my * (0.5f - q2q2 - q4q4) + 2.0f * mz * (q3q4 - q1q2); - bx = sqrt((hx * hx) + (hy * hy)); - bz = 2.0f * mx * (q2q4 - q1q3) + 2.0f * my * (q3q4 + q1q2) + 2.0f * mz * (0.5f - q2q2 - q3q3); - - // Estimated direction of gravity and magnetic field - vx = 2.0f * (q2q4 - q1q3); - vy = 2.0f * (q1q2 + q3q4); - vz = q1q1 - q2q2 - q3q3 + q4q4; - wx = 2.0f * bx * (0.5f - q3q3 - q4q4) + 2.0f * bz * (q2q4 - q1q3); - wy = 2.0f * bx * (q2q3 - q1q4) + 2.0f * bz * (q1q2 + q3q4); - wz = 2.0f * bx * (q1q3 + q2q4) + 2.0f * bz * (0.5f - q2q2 - q3q3); - - // Error is cross product between estimated direction and measured direction of gravity - ex = (ay * vz - az * vy) + (my * wz - mz * wy); - ey = (az * vx - ax * vz) + (mz * wx - mx * wz); - ez = (ax * vy - ay * vx) + (mx * wy - my * wx); - if (Ki > 0.0f) { - eInt[0] += ex; // accumulate integral error - eInt[1] += ey; - eInt[2] += ez; - } else { - eInt[0] = 0.0f; // prevent integral wind up - eInt[1] = 0.0f; - eInt[2] = 0.0f; - } - - // Apply feedback terms - gx = gx + Kp * ex + Ki * eInt[0]; - gy = gy + Kp * ey + Ki * eInt[1]; - gz = gz + Kp * ez + Ki * eInt[2]; - - // Integrate rate of change of quaternion - pa = q2; - pb = q3; - pc = q4; - q1 = q1 + (-q2 * gx - q3 * gy - q4 * gz) * (0.5f * deltat); - q2 = pa + (q1 * gx + pb * gz - pc * gy) * (0.5f * deltat); - q3 = pb + (q1 * gy - pa * gz + pc * gx) * (0.5f * deltat); - q4 = pc + (q1 * gz + pa * gy - pb * gx) * (0.5f * deltat); - - // Normalise quaternion - norm = sqrt(q1 * q1 + q2 * q2 + q3 * q3 + q4 * q4); - norm = 1.0f / norm; - q[0] = q1 * norm; - q[1] = q2 * norm; - q[2] = q3 * norm; - q[3] = q4 * norm; - - } }; #endif \ No newline at end of file