Class of MPU9250
Dependencies: AHRS_fillter mbed
Fork of MPU9250AHRS by
AHRS.cpp
- Committer:
- icyzkungz
- Date:
- 2016-01-20
- Revision:
- 7:3e74239e3778
- Parent:
- 6:5665d427bceb
- Child:
- 8:928673148b55
File content as of revision 7:3e74239e3778:
#include "AHRS.h" #define Kp 5.1f * 5.0f // these are the free parameters in the Mahony filter and fusion scheme, Kp for proportional feedback, Ki for integral #define Ki 1.0f /*AHRS::AHRS(PinName sda, PinName scl, PinName tx, PinName rx, int address):MPU9250(sda,scl,tx,rx,address) { for(int i=0; i<=3; i++) { eInt[i] = 0; q[i] = 0; // vector to hold quaternion } q[0] = 1.0f; PI = 3.14159265358979323846f; GyroMeasError = PI * (60.0f / 180.0f); // gyroscope measurement error in rads/s (start at 60 deg/s), then reduce after ~10 s to 3 beta = sqrt(3.0f / 4.0f) * GyroMeasError; // compute beta GyroMeasDrift = PI * (1.0f / 180.0f); // gyroscope measurement drift in rad/s/s (start at 0.0 deg/s/s) 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 }*/ /*void AHRS::MadgwickQuaternionUpdate(float ax, float ay, float az, float gx, float gy, float gz, float mx, float my, float mz, float deltat) { 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; yaw = atan2(2.0f * (q[1] * q[2] + q[0] * q[3]), q[0] * q[0] + q[1] * q[1] - q[2] * q[2] - q[3] * q[3]); pitch = -asin(2.0f * (q[1] * q[3] - q[0] * q[2])); roll = atan2(2.0f * (q[0] * q[1] + q[2] * q[3]), q[0] * q[0] - q[1] * q[1] - q[2] * q[2] + q[3] * q[3]); float Xh = mx*cos(pitch)+my*sin(roll)*sin(pitch)-mz*cos(roll)*sin(pitch); float Yh = my*cos(roll)+mz*sin(roll); float yawmag = atan2(Yh,Xh)+PI; //////test.printf("Xh= %f Yh= %f ",Xh,Yh); //////test.printf("Yaw[mag]= %f\n\r",yawmag*180.0f/PI); //test.printf(",%f",yawmag*180.0f/PI); pitch *= 180.0f / PI; yaw *= 180.0f / PI; yaw += 180.0f; // Declination at Danville, California is 13 degrees 48 minutes and 47 seconds on 2014-04-04 roll *= 180.0f / PI; } // Similar to Madgwick scheme but uses proportional and integral filtering on the error between estimated reference vectors and // measured ones. void AHRS::MahonyQuaternionUpdate(float ax, float ay, float az, float gx, float gy, float gz, float mx, float my, float mz, float deltat) { q1 = q[0]; q2 = q[1]; q3 = q[2]; q4 = q[3]; // short name local variable for readability // Auxiliary variables to avoid repeated arithmetic q1q1 = q1 * q1; q1q2 = q1 * q2; q1q3 = q1 * q3; q1q4 = q1 * q4; q2q2 = q2 * q2; q2q3 = q2 * q3; q2q4 = q2 * q4; q3q3 = q3 * q3; q3q4 = q3 * q4; 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; yaw = atan2(2.0f * (q[1] * q[2] + q[0] * q[3]), q[0] * q[0] + q[1] * q[1] - q[2] * q[2] - q[3] * q[3]); pitch = -asin(2.0f * (q[1] * q[3] - q[0] * q[2])); roll = atan2(2.0f * (q[0] * q[1] + q[2] * q[3]), q[0] * q[0] - q[1] * q[1] - q[2] * q[2] + q[3] * q[3]); Xh = mx*cos(pitch)+my*sin(roll)*sin(pitch)-mz*cos(roll)*sin(pitch); Yh = my*cos(roll)+mz*sin(roll); yawmag = atan2(Yh,Xh)+PI; ////////////test.printf("Xh= %f Yh= %f ",Xh,Yh); //////test.printf("Yaw[mag]= %f\n\r",yawmag*180.0f/PI); //test.printf(",%f",yawmag*180.0f/PI); pitch *= 180.0f / PI; yaw *= 180.0f / PI; yaw += 180.0f; // Declination at Danville, California is 13 degrees 48 minutes and 47 seconds on 2014-04-04 roll *= 180.0f / PI; }*/ void AHRS::MadgwickQuaternionUpdate() { 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 AHRS::MahonyQuaternionUpdate() { q1 = q[0]; q2 = q[1]; q3 = q[2]; q4 = q[3]; // short name local variable for readability // Auxiliary variables to avoid repeated arithmetic q1q1 = q1 * q1; q1q2 = q1 * q2; q1q3 = q1 * q3; q1q4 = q1 * q4; q2q2 = q2 * q2; q2q3 = q2 * q3; q2q4 = q2 * q4; q3q3 = q3 * q3; q3q4 = q3 * q4; 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; } void AHRS::TimeStart() { t.start(); } void AHRS::TimeCal() { Now = t.read_us(); deltat = (float)((Now - lastUpdate)/1000000.0f) ; // set integration time by time elapsed since last filter update lastUpdate = Now; sum += deltat; sumCount++; } void AHRS::Run() { ReadRawAccGyroMag(); TimeCal(); MadgwickQuaternionUpdate(); delt_t = t.read_ms() - count; if (delt_t > 500) { // update LCD once per half-second independent of read rate /*pc.printf("ax = %f", 1000*ax); pc.printf(" ay = %f", 1000*ay); pc.printf(" az = %f mg\n\r", 1000*az); pc.printf("gx = %f", gx); pc.printf(" gy = %f", gy); pc.printf(" gz = %f deg/s\n\r", gz); pc.printf("mx = %f", mx); pc.printf(" my = %f", my); pc.printf(" mz = %f mG\n\r", mz);*/ //pc.printf("%f,%f,%f",mx,my,mz); whoami = readByte(AK8963_ADDRESS, AK8963_ST2); // Read WHO_AM_I register for MPU-9250 // pc.printf("I AM 0x%x\n\r", whoami); pc.printf("I SHOULD BE 0x10\n\r"); if(whoami == 0x14) { printf("I AM 0x%x\n\r", whoami); while(1); } readTempData(); temperature = ((float) temperature) / 333.87f + 21.0f; // Temperature in degrees Centigrade //pc.printf(" temperature = %f C\n\r", temperature); // pc.printf("q0 = %f\n\r", q[0]); // pc.printf("q1 = %f\n\r", q[1]); // pc.printf("q2 = %f\n\r", q[2]); // pc.printf("q3 = %f\n\r", q[3]); // Define output variables from updated quaternion---these are Tait-Bryan angles, commonly used in aircraft orientation. // In this coordinate system, the positive z-axis is down toward Earth. // 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. // Pitch is angle between sensor x-axis and Earth ground plane, toward the Earth is positive, up toward the sky is negative. // Roll is angle between sensor y-axis and Earth ground plane, y-axis up is positive roll. // These arise from the definition of the homogeneous rotation matrix constructed from quaternions. // Tait-Bryan angles as well as Euler angles are non-commutative; that is, the get the correct orientation the rotations must be // applied in the correct order which for this configuration is yaw, pitch, and then roll. // For more see http://en.wikipedia.org/wiki/Conversion_between_quaternions_and_Euler_angles which has additional links. yaw = atan2(2.0f * (q[1] * q[2] + q[0] * q[3]), q[0] * q[0] + q[1] * q[1] - q[2] * q[2] - q[3] * q[3]); pitch = -asin(2.0f * (q[1] * q[3] - q[0] * q[2])); roll = atan2(2.0f * (q[0] * q[1] + q[2] * q[3]), q[0] * q[0] - q[1] * q[1] - q[2] * q[2] + q[3] * q[3]); Xh = mx*cos(pitch)+my*sin(roll)*sin(pitch)-mz*cos(roll)*sin(pitch); Yh = my*cos(roll)+mz*sin(roll); yawmag = atan2(Yh,Xh)+PI; //pc.printf("Xh= %f Yh= %f ",Xh,Yh); printf("Yaw[mag]= %f\n\r",yawmag*180.0f/PI); printf(",%f",yawmag*180.0f/PI); pitch *= 180.0f / PI; yaw *= 180.0f / PI; yaw += 180.0f; // Declination at Danville, California is 13 degrees 48 minutes and 47 seconds on 2014-04-04 roll *= 180.0f / PI; //pc.printf(",%f,%f,%f\n",roll,pitch,yaw); printf("Yaw, Pitch, Roll: %f %f %f\n\r", yaw, pitch, roll); //pc.printf("average rate = %f\n\r", (float) sumCount/sum); // sprintf(buffer, "YPR: %f %f %f", yaw, pitch, roll); // lcd.printString(buffer, 0, 4); // sprintf(buffer, "rate = %f", (float) sumCount/sum); // lcd.printString(buffer, 0, 5); myled= !myled; count = t.read_ms(); if(count > 1<<21) { t.start(); // start the timer over again if ~30 minutes has passed count = 0; deltat= 0; lastUpdate = t.read_us(); } sum = 0; sumCount = 0; } } void AHRS::printRollPitchYaw() { //test.printf("roll : %f, pitch : %f, yaw : %f\n",roll,pitch,yaw); }