70 lines
1.9 KiB
C++
70 lines
1.9 KiB
C++
//CONSTANTS
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const float alpha = 0.95;
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const int acc_overflow_value = 65535;
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const int gyro_overflow_value = 4558; // 4096+512-50=4558 ?
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//IMU VARIABLES
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int ax, ay, az;
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int cx, cy, cz;
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int gx, gy, gz;
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float gt;
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float acc_pitch;
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float pitch_rate;
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float dAngle, estAngle;
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float pitch = 0;
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float pitch_prev = 0;
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void readIMU() {
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//Acceletometer
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ax = convertInt(IMU.accelerometer_x( IMU.readFromAccelerometer() ), acc_overflow_value);
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ay = convertInt(IMU.accelerometer_y( IMU.readFromAccelerometer() ), acc_overflow_value);
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az = convertInt(IMU.accelerometer_z( IMU.readFromAccelerometer() ), acc_overflow_value);
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//Magnetometer
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cx = IMU.compass_x( IMU.readFromCompass() );
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cy = IMU.compass_y( IMU.readFromCompass() );
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cz = IMU.compass_z( IMU.readFromCompass() );
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// Gyrocope
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gx = convertInt(IMU.gyro_x( IMU.readGyro() ), gyro_overflow_value); // gx - Pitch rate
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gy = convertInt(IMU.gyro_y( IMU.readGyro() ), gyro_overflow_value); // gy - Roll rate
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gz = convertInt(IMU.gyro_z( IMU.readGyro() ), gyro_overflow_value); // gz - Yaw rate
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//Temperature sensor
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gt = IMU.temp ( IMU.readGyro() );
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// Pitch angle from accelerometer
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acc_pitch = -1 * atan2(ax, sqrt((pow(ay, 2) + pow(az, 2)))) * 180.0 / PI;
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//Pitch rate from gyroscope
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pitch_rate = -gx;
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//Complementary filter
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dAngle = pitch_rate * dT_s;
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pitch = acc_pitch * (1 - alpha) + ((dAngle + pitch_prev) * alpha);
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pitch_prev = pitch;
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}
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int convertInt(int raw, int overflow_value_) {
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//For some reason the ints in the example behaves as unsigned int.. Maybe look at the .cpp code, might be something there, if not. This works OK.
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if (raw > (overflow_value_ / 2)) {
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return (raw - overflow_value_);
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}
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else {
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return raw;
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}
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}
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