Implemented first Hangar-Service
Dependencies: CalibrateMagneto QuaternionMath
Fork of SML2 by
Diff: SensorFusion.cpp
- Revision:
- 15:4488660e1a3b
- Child:
- 16:3e2468d4f4c1
diff -r d9fbb3ccd482 -r 4488660e1a3b SensorFusion.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/SensorFusion.cpp Wed Mar 18 15:34:51 2015 +0000 @@ -0,0 +1,142 @@ +#include "SensorFusion.h" + +#define DEBUG "SensorFusion" +#include "Logger.h" + +SensorFusion::SensorFusion(I2C &i2c) : accel(i2c), gyro(i2c), magneto(i2c), + q(1, 0, 0, 0), // output quaternion + deltat(0.010), // sec + beta(2.6) // correction gain +{ +} + +bool SensorFusion::start() +{ + accel.powerOn(); + accel.start(); + + magneto.powerOn(); + if (magneto.performSelfTest() == false) { + return false; + } + magneto.start(); + + // Since everything is synced to gyro interrupt, start it last + gyro.setDelegate(*this); + gyro.powerOn(); + gyro.start(); + + return true; +} + +void SensorFusion::stop() +{ + gyro.stop(); + magneto.stop(); + accel.stop(); + + gyro.powerOff(); + magneto.powerOff(); + accel.powerOff(); +} + +static float const deg_to_radian = 0.0174532925f; +static float const radian_to_deg = 57.2957795131f; + +void SensorFusion::sensorUpdate(Vector3 gyro_degrees) +{ + Vector3 const gyro_reading = gyro_degrees * deg_to_radian; + Vector3 const accel_reading = accel.read(); + Vector3 const magneto_reading = magneto.read(); + + updateFilter( accel_reading.x, accel_reading.y, accel_reading.z, + gyro_reading.x, gyro_reading.y, gyro_reading.z, + magneto_reading.x, magneto_reading.y, magneto_reading.z); + + Vector3 const fused = q.getEulerAngles() * radian_to_deg; + + sensorTick(fused, accel_reading, magneto_reading, gyro_degrees, q); +} + +void SensorFusion::updateFilter(float ax, float ay, float az, float gx, float gy, float gz, float mx, float my, float mz) +{ + float q1 = q.w, q2 = q.v.x, q3 = q.v.y, q4 = q.v.z; // short name local variable for readability + float norm; + float s1, s2, s3, s4; + + // Auxiliary variables to avoid repeated arithmetic + const float _2q1 = 2.0f * q1; + const float _2q2 = 2.0f * q2; + const float _2q3 = 2.0f * q3; + const float _2q4 = 2.0f * q4; + const float _2q1q3 = 2.0f * q1 * q3; + const float _2q3q4 = 2.0f * q3 * q4; + const float q1q1 = q1 * q1; + const float q1q2 = q1 * q2; + const float q1q3 = q1 * q3; + const float q1q4 = q1 * q4; + const float q2q2 = q2 * q2; + const float q2q3 = q2 * q3; + const float q2q4 = q2 * q4; + const float q3q3 = q3 * q3; + const float q3q4 = q3 * q4; + const 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 + const float _2q1mx = 2.0f * q1 * mx; + const float _2q1my = 2.0f * q1 * my; + const float _2q1mz = 2.0f * q1 * mz; + const float _2q2mx = 2.0f * q2 * mx; + const float hx = mx * q1q1 - _2q1my * q4 + _2q1mz * q3 + mx * q2q2 + _2q2 * my * q3 + _2q2 * mz * q4 - mx * q3q3 - mx * q4q4; + const float hy = _2q1mx * q4 + my * q1q1 - _2q1mz * q2 + _2q2mx * q3 - my * q2q2 + my * q3q3 + _2q3 * mz * q4 - my * q4q4; + const float _2bx = sqrt(hx * hx + hy * hy); + const float _2bz = -_2q1mx * q3 + _2q1my * q2 + mz * q1q1 + _2q2mx * q4 - mz * q2q2 + _2q3 * my * q4 - mz * q3q3 + mz * q4q4; + const float _4bx = 2.0f * _2bx; + const float _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 + const float qDot1 = 0.5f * (-q2 * gx - q3 * gy - q4 * gz) - beta * s1; + const float qDot2 = 0.5f * (q1 * gx + q3 * gz - q4 * gy) - beta * s2; + const float qDot3 = 0.5f * (q1 * gy - q2 * gz + q4 * gx) - beta * s3; + const float 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.w = q1 * norm; + q.v.x = q2 * norm; + q.v.y = q3 * norm; + q.v.z = q4 * norm; +}