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/************************************************************************/

/* Flight Attitude                                                      */

/************************************************************************/

#include <stdlib.h>

#include <avr/io.h>

#include "attitude.h"

#include "dongfangMath.h"

// where our main data flow comes from.

#include "analog.h"

#include "configuration.h"

// Some calculations are performed depending on some stick related things.

#include "controlMixer.h"

// For Servo_On / Off

// #include "timer2.h"

#ifdef USE_MK3MAG

#include "mk3mag.h"

#include "gps.h"

#endif

#define CHECK_MIN_MAX(value, min, max) {if(value < min) value = min; else if(value > max) value = max;}

/*

 * Gyro readings, as read from the analog module. It would have been nice to flow

 * them around between the different calculations as a struct or array (doing

 * things functionally without side effects) but this is shorter and probably

 * faster too.

 * The variables are overwritten at each attitude calculation invocation - the values

 * are not preserved or reused.

 */

int16_t pitchRate, rollRate, yawRate;

// With different (less) filtering

int16_t pitchRate_PID, rollRate_PID;

int16_t pitchDifferential, rollDifferential;

/*

 * Gyro readings, after performing "axis coupling" - that is, the transfomation

 * of rotation rates from the airframe-local coordinate system to a ground-fixed

 * coordinate system. If axis copling is disabled, the gyro readings will be

 * copied into these directly.

 * These are global for the same pragmatic reason as with the gyro readings.

 * The variables are overwritten at each attitude calculation invocation - the values

 * are not preserved or reused.

 */

int16_t ACPitchRate, ACRollRate, ACYawRate;

/*

 * Gyro integrals. These are the rotation angles of the airframe compared to the

 * horizontal plane, yaw relative to yaw at start.

 */

int32_t pitchAngle, rollAngle, yawAngle;

int readingHeight = 0;

// compass course

int16_t compassHeading = -1; // negative angle indicates invalid data.

int16_t compassCourse = -1;

int16_t compassOffCourse = 0;

uint16_t updateCompassCourse = 0;

uint8_t compassCalState = 0;

// uint8_t FunnelCourse = 0;

uint16_t badCompassHeading = 500;

int32_t yawGyroHeading; // Yaw Gyro Integral supported by compass

#define PITCHROLLOVER180 (GYRO_DEG_FACTOR_PITCHROLL * 180L)

#define PITCHROLLOVER360 (GYRO_DEG_FACTOR_PITCHROLL * 360L)

#define YAWOVER360       (GYRO_DEG_FACTOR_YAW * 360L)

int32_t pitchCorrectionSum = 0, rollCorrectionSum = 0;

/*

 * Experiment: Compensating for dynamic-induced gyro biasing.

 */

int16_t dynamicOffsetPitch = 0, dynamicOffsetRoll = 0, dynamicOffsetYaw = 0;

// int16_t savedDynamicOffsetPitch = 0, savedDynamicOffsetRoll = 0;

// int32_t dynamicCalPitch, dynamicCalRoll, dynamicCalYaw;

// int16_t dynamicCalCount;

/************************************************************************

 * Set inclination angles from the acc. sensor data.                    

 * If acc. sensors are not used, set to zero.                          

 * TODO: One could use inverse sine to calculate the angles more        

 * accurately, but since: 1) the angles are rather small at times when

 * it makes sense to set the integrals (standing on ground, or flying at  

 * constant speed, and 2) at small angles a, sin(a) ~= constant * a,    

 * it is hardly worth the trouble.                                      

 ************************************************************************/

int32_t getPitchAngleEstimateFromAcc(void) {

  return GYRO_ACC_FACTOR * (int32_t)filteredPitchAxisAcc;

}

int32_t getRollAngleEstimateFromAcc(void) {

  return GYRO_ACC_FACTOR * (int32_t)filteredRollAxisAcc;

}

void setStaticAttitudeAngles(void) {

#ifdef ATTITUDE_USE_ACC_SENSORS

  pitchAngle = getPitchAngleEstimateFromAcc();

  rollAngle = getRollAngleEstimateFromAcc();

#else

  pitchAngle = 0;

  rollAngle = 0;

#endif

}

/************************************************************************

 * Neutral Readings                                                    

 ************************************************************************/

void attitude_setNeutral(void) {

  // Servo_Off(); // disable servo output. TODO: Why bother? The servos are going to make a jerk anyway.

  dynamicParams.AxisCoupling1 = dynamicParams.AxisCoupling2 = 0;

  dynamicOffsetPitch = dynamicOffsetRoll = 0;

  // Calibrate hardware.

  analog_calibrate();

  // reset gyro readings

  pitchRate = rollRate = yawRate = 0;

  // reset gyro integrals to acc guessing

  setStaticAttitudeAngles();

  yawAngle = 0;

  // update compass course to current heading

  compassCourse = compassHeading;

  // Inititialize YawGyroIntegral value with current compass heading

  yawGyroHeading = (int32_t)compassHeading * GYRO_DEG_FACTOR_YAW;

  // Servo_On(); //enable servo output

}

/************************************************************************

 * Get sensor data from the analog module, and release the ADC          

 * TODO: Ultimately, the analog module could do this (instead of dumping

 * the values into variables).                                          

 *************************************************************************/

void getAnalogData(void) {

  // For the differential calculation. Diff. is not supported right now.

  // int16_t d2Pitch, d2Roll;

  pitchRate_PID = (hiResPitchGyro + dynamicOffsetPitch) / HIRES_GYRO_INTEGRATION_FACTOR;

  pitchRate = (filteredHiResPitchGyro + dynamicOffsetPitch) / HIRES_GYRO_INTEGRATION_FACTOR;

  pitchDifferential = pitchGyroD;

  rollRate_PID = (hiResRollGyro + dynamicOffsetRoll) / HIRES_GYRO_INTEGRATION_FACTOR;

  rollRate = (filteredHiResRollGyro + dynamicOffsetRoll) / HIRES_GYRO_INTEGRATION_FACTOR;

  rollDifferential = rollGyroD;

  yawRate = yawGyro + dynamicOffsetYaw;

  // We are done reading variables from the analog module. Interrupt-driven sensor reading may restart.

  analogDataReady = 0;

  analog_start();

}

/************************************************************************

 * Axis coupling, H&I Style                                            

 * Currently not working (and there is a bug in it,

 * which causes unstable flight in heading-hold mode).

 ************************************************************************/

void H_and_I_axisCoupling(void) {

  int32_t tmpl = 0, tmpl2 = 0, tmp13 = 0, tmp14 = 0;

  int16_t CouplingNickRoll = 0, CouplingRollNick = 0;

  tmp13 = (rollRate * pitchAngle) / 2048L;

  tmp13 *= dynamicParams.AxisCoupling2; // 65

  tmp13 /= 4096L;

  CouplingNickRoll = tmp13;

  tmp14 = (pitchRate * rollAngle) / 2048L;

  tmp14 *= dynamicParams.AxisCoupling2; // 65

  tmp14 /= 4096L;

  CouplingRollNick = tmp14;

  tmp14 -= tmp13;

  ACYawRate = yawRate + tmp14;

  /*

  if(!dynamicParams.AxisCouplingYawCorrection) ACYawRate = yawRate - tmp14 / 2; // force yaw

  else ACYawRate

  */

  tmpl = ((yawRate + tmp14) * pitchAngle) / 2048L;

  tmpl *= dynamicParams.AxisCoupling1;

  tmpl /= 4096L;

  tmpl2 = ((yawRate + tmp14) * rollAngle) / 2048L;

  tmpl2 *= dynamicParams.AxisCoupling1;

  tmpl2 /= 4096L;

  // if(abs(yawRate > 64)) {

  // if(labs(tmpl) > 128 || labs(tmpl2) > 128) FunnelCourse = 1;

  // }

  ACPitchRate = pitchRate - tmpl2 + tmpl / 100L;

  ACRollRate = rollRate + tmpl - tmpl2 / 100L;

}

/*

 * This is the standard flight-style coordinate system transformation

 * (from airframe-local axes to a ground-based system). For some reason

 * the MK uses a left-hand coordinate system. The tranformation has been

 * changed accordingly.

 */

void trigAxisCoupling(void) {

  int16_t cospitch = int_cos(pitchAngle);

  int16_t cosroll =  int_cos(rollAngle);

  int16_t sinroll =  int_sin(rollAngle);

  int16_t tanpitch = int_tan(pitchAngle);

#define ANTIOVF 1024

  ACPitchRate =            ((int32_t)pitchRate * cosroll - (int32_t)yawRate * sinroll) / (int32_t)MATH_UNIT_FACTOR;

  ACRollRate = rollRate + (((int32_t)pitchRate * sinroll / ANTIOVF * tanpitch + (int32_t)yawRate * int_cos(rollAngle) / ANTIOVF * tanpitch) / ((int32_t)MATH_UNIT_FACTOR / ANTIOVF * MATH_UNIT_FACTOR));

  ACYawRate =             ((int32_t)pitchRate * sinroll) / cospitch + ((int32_t)yawRate * cosroll) / cospitch;

}

void integrate(void) {

  // First, perform axis coupling. If disabled xxxRate is just copied to ACxxxRate.

  if(!looping && (staticParams.GlobalConfig & CFG_AXIS_COUPLING_ACTIVE)) {

    // The rotary rate limiter bit is abused for selecting axis coupling algorithm instead.

    if (staticParams.GlobalConfig & CFG_ROTARY_RATE_LIMITER)

      trigAxisCoupling();    

    else

      H_and_I_axisCoupling();

  } else {

    ACPitchRate = pitchRate;

    ACRollRate = rollRate;

    ACYawRate = yawRate;

  }

  DebugOut.Analog[3] = pitchRate;

  DebugOut.Analog[3 + 3] = ACPitchRate;

  DebugOut.Analog[4] = rollRate;

  DebugOut.Analog[4 + 3] = ACRollRate;

  DebugOut.Analog[5] = yawRate;

  DebugOut.Analog[5 + 3] = ACYawRate;

  /*

  DebugOut.Analog[9] = int_cos(pitchAngle);

  DebugOut.Analog[10] = int_sin(pitchAngle);

  DebugOut.Analog[11] = int_tan(pitchAngle);

  */

  /*

   * Yaw

   * Calculate yaw gyro integral (~ to rotation angle)

   * Limit yawGyroHeading proportional to 0 deg to 360 deg

   */

  yawGyroHeading += ACYawRate;

  // Why is yawAngle not wrapped 'round?

  yawAngle += ACYawRate;

  if(yawGyroHeading >= YAWOVER360) {

    yawGyroHeading -= YAWOVER360;  // 360 deg. wrap

  } else if(yawGyroHeading < 0) {

    yawGyroHeading += YAWOVER360;

  }

  /*

   * Pitch axis integration and range boundary wrap.

   */

  pitchAngle += ACPitchRate;

  if(pitchAngle > PITCHROLLOVER180) {

    pitchAngle -= PITCHROLLOVER360;

  } else if (pitchAngle <= -PITCHROLLOVER180) {

    pitchAngle += PITCHROLLOVER360;

  }

  /*

   * Pitch axis integration and range boundary wrap.

   */

  rollAngle  += ACRollRate;

  if(rollAngle > PITCHROLLOVER180) {

    rollAngle -= PITCHROLLOVER360;

  } else if (rollAngle <= -PITCHROLLOVER180) {

    rollAngle += PITCHROLLOVER360;

  }

}

/************************************************************************

 * A kind of 0'th order integral correction, that corrects the integrals

 * directly. This is the "gyroAccFactor" stuff in the original code.

 * There is (there) also what I would call a  "minus 1st order correction"

 * - it corrects the differential of the integral = the gyro offsets.

 * That should only be necessary with drifty gyros like ENC-03.

 ************************************************************************/

void correctIntegralsByAcc0thOrder(void) {

  // TODO: Consider changing this to: Only correct when integrals are less than ...., or only correct when angular velocities

  // are less than ....., or reintroduce Kalman.

  // Well actually the Z axis acc. check is not so silly.

  if(!looping && //((ZAxisAcc >= -4) || (MKFlags & MKFLAG_MOTOR_RUN))) { // if not looping in any direction

     ZAxisAcc >= -dynamicParams.UserParams[7] && ZAxisAcc <= dynamicParams.UserParams[7]) {

    DebugOut.Digital[0] = 1;

    uint8_t permilleAcc = staticParams.GyroAccFactor; // NOTE!!! The meaning of this value has changed!!

    uint8_t debugFullWeight = 1;

    int32_t accDerivedPitch = getPitchAngleEstimateFromAcc();

    int32_t accDerivedRoll = getRollAngleEstimateFromAcc();

    if((maxControlPitch > 64) || (maxControlRoll > 64)) { // reduce effect during stick commands

      permilleAcc /= 2;

      debugFullWeight = 0;

    }

    if(abs(controlYaw) > 25) { // reduce further if yaw stick is active

      permilleAcc /= 2;

      debugFullWeight = 0;

    }

    /*

     * Add to each sum: The amount by which the angle is changed just below.

     */

    pitchCorrectionSum += permilleAcc * (accDerivedPitch - pitchAngle);

    rollCorrectionSum += permilleAcc * (accDerivedRoll - rollAngle);

    // There should not be a risk of overflow here, since the integrals do not exceed a few 100000.

    pitchAngle = ((int32_t)(1000 - permilleAcc) * pitchAngle + (int32_t)permilleAcc * accDerivedPitch) / 1000L;

    rollAngle = ((int32_t)(1000 - permilleAcc) * rollAngle + (int32_t)permilleAcc * accDerivedRoll) / 1000L;

    DebugOut.Digital[1] = debugFullWeight;

  } else {

    DebugOut.Digital[0] = 0;

  }

}

/************************************************************************

 * This is an attempt to correct not the error in the angle integrals

 * (that happens in correctIntegralsByAcc0thOrder above) but rather the

 * cause of it: Gyro drift, vibration and rounding errors.

 * All the corrections made in correctIntegralsByAcc0thOrder over

 * MINUSFIRSTORDERCORRECTION_TIME cycles are summed up. This number is

 * then divided by MINUSFIRSTORDERCORRECTION_TIME to get the approx.

 * correction that should have been applied to each iteration to fix

 * the error. This is then added to the dynamic offsets.

 ************************************************************************/

// 2 times / sec.

#define DRIFTCORRECTION_TIME 488/2

void driftCompensation(void) {

  static int16_t timer = DRIFTCORRECTION_TIME;

  int16_t deltaCompensation;

  if (! --timer) {

    timer = DRIFTCORRECTION_TIME;

    deltaCompensation = ((pitchCorrectionSum + 1000L * DRIFTCORRECTION_TIME / 2) / 1000 / DRIFTCORRECTION_TIME);

    CHECK_MIN_MAX(deltaCompensation, -staticParams.DriftComp, staticParams.DriftComp);

    dynamicOffsetPitch += deltaCompensation / staticParams.GyroAccTrim;

    deltaCompensation = ((rollCorrectionSum + 1000L * DRIFTCORRECTION_TIME / 2) / 1000 / DRIFTCORRECTION_TIME);

    CHECK_MIN_MAX(deltaCompensation, -staticParams.DriftComp, staticParams.DriftComp);

    dynamicOffsetRoll += deltaCompensation / staticParams.GyroAccTrim;

    pitchCorrectionSum = rollCorrectionSum = 0;

    DebugOut.Analog[28] = dynamicOffsetPitch;

    DebugOut.Analog[29] = dynamicOffsetRoll;

  }

}

/************************************************************************

 * Main procedure.

 ************************************************************************/

void calculateFlightAttitude(void) {  

  getAnalogData();

  integrate();

#ifdef ATTITUDE_USE_ACC_SENSORS

  correctIntegralsByAcc0thOrder();

  driftCompensation();

#endif

}

/*

void updateCompass(void) {

  int16_t w, v, r,correction, error;

  if(compassCalState && !(MKFlags & MKFLAG_MOTOR_RUN)) {

    setCompassCalState();

  } else {

    // get maximum attitude angle

    w = abs(pitchAngle / 512);

    v = abs(rollAngle / 512);

    if(v > w) w = v;

    correction = w / 8 + 1;

    // calculate the deviation of the yaw gyro heading and the compass heading

    if (compassHeading < 0) error = 0; // disable yaw drift compensation if compass heading is undefined

    else error = ((540 + compassHeading - (yawGyroHeading / GYRO_DEG_FACTOR_YAW)) % 360) - 180;

    if(abs(yawRate) > 128) { // spinning fast

      error = 0;

    }

    if(!badCompassHeading && w < 25) {

      if(updateCompassCourse) {

        beep(200);

        yawGyroHeading = (int32_t)compassHeading * GYRO_DEG_FACTOR_YAW;

        compassCourse = (int16_t)(yawGyroHeading / GYRO_DEG_FACTOR_YAW);

        updateCompassCourse = 0;

      }

    }

    yawGyroHeading += (error * 8) / correction;

    w = (w * dynamicParams.CompassYawEffect) / 32;

    w = dynamicParams.CompassYawEffect - w;

    if(w >= 0) {

      if(!badCompassHeading) {

        v = 64 + (maxControlPitch + maxControlRoll) / 8;

        // calc course deviation

        r = ((540 + (yawGyroHeading / GYRO_DEG_FACTOR_YAW) - compassCourse) % 360) - 180;

        v = (r * w) / v; // align to compass course

        // limit yaw rate

        w = 3 * dynamicParams.CompassYawEffect;

        if (v > w) v = w;

        else if (v < -w) v = -w;

        yawAngle += v;

      }

      else

        { // wait a while

          badCompassHeading--;

        }

    }

    else {  // ignore compass at extreme attitudes for a while

      badCompassHeading = 500;

    }

  }

}

*/

/*

 * This is part of an experiment to measure average sensor offsets caused by motor vibration,

 * and to compensate them away. It brings about some improvement, but no miracles.

 * As long as the left stick is kept in the start-motors position, the dynamic compensation

 * will measure the effect of vibration, to use for later compensation. So, one should keep

 * the stick in the start-motors position for a few seconds, till all motors run (at the wrong

 * speed unfortunately... must find a better way)

 */

/*

void attitude_startDynamicCalibration(void) {

  dynamicCalPitch = dynamicCalRoll = dynamicCalYaw = dynamicCalCount = 0;

  savedDynamicOffsetPitch = savedDynamicOffsetRoll = 1000;

}

void attitude_continueDynamicCalibration(void) {

  // measure dynamic offset now...

  dynamicCalPitch += hiResPitchGyro;

  dynamicCalRoll += hiResRollGyro;

  dynamicCalYaw += rawYawGyroSum;

  dynamicCalCount++;

  // Param6: Manual mode. The offsets are taken from Param7 and Param8.

  if (dynamicParams.UserParam6 || 1) { // currently always enabled.

    // manual mode

    dynamicOffsetPitch = dynamicParams.UserParam7 - 128;

    dynamicOffsetRoll = dynamicParams.UserParam8 - 128;

  } else {

    // use the sampled value (does not seem to work so well....)

    dynamicOffsetPitch = savedDynamicOffsetPitch = -dynamicCalPitch / dynamicCalCount;

    dynamicOffsetRoll = savedDynamicOffsetRoll = -dynamicCalRoll / dynamicCalCount;

    dynamicOffsetYaw = -dynamicCalYaw / dynamicCalCount;

  }

  // keep resetting these meanwhile, to avoid accumulating errors.

  setStaticAttitudeIntegrals();

  yawAngle = 0;

}

*/