Subversion Repositories FlightCtrl

#include <stdlib.h>

#include <avr/io.h>

#include "attitude.h"

#include "dongfangMath.h"

#include "commands.h"

// For scope debugging only!

#include "rc.h"

// where our main data flow comes from.

#include "analog.h"

#include "configuration.h"

#include "output.h"

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

#include "controlMixer.h"

#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 rate_ATT[2], yawRate;

// With different (less) filtering

int16_t rate_PID[2];

int16_t differential[2];

/*

 * 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 ACRate[2], ACYawRate;

/*

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

 * horizontal plane, yaw relative to yaw at start.

 */

int32_t attitude[2];

//int readingHeight = 0;

// Yaw angle and compass stuff.

int32_t headingError;

// The difference between the above 2 (heading - course) on a -180..179 degree interval.

// Not necessary. Never read anywhere.

// int16_t compassOffCourse = 0;

uint16_t ignoreCompassTimer = 0;// 500;

int32_t heading; // Yaw Gyro Integral supported by compass

int16_t yawGyroDrift;

int16_t correctionSum[2] = { 0, 0 };

// For NaviCTRL use.

int16_t averageAcc[2] = { 0, 0 }, averageAccCount = 0;

/*

 * Experiment: Compensating for dynamic-induced gyro biasing.

 */

int16_t driftComp[2] = { 0, 0 }, driftCompYaw = 0;

// int16_t savedDynamicOffsetPitch = 0, savedDynamicOffsetRoll = 0;

// int32_t dynamicCalPitch, dynamicCalRoll, dynamicCalYaw;

// int16_t dynamicCalCount;

// uint16_t accVector;

// uint32_t gyroActivity;

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

 * 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 getAngleEstimateFromAcc(uint8_t axis) {

  //int32_t correctionTerm = (dynamicParams.levelCorrection[axis] - 128) * 256L;

  return (int32_t) GYRO_ACC_FACTOR * (int32_t) filteredAcc[axis]; // + correctionTerm;

  // return 342L * filteredAcc[axis];

}

void setStaticAttitudeAngles(void) {

#ifdef ATTITUDE_USE_ACC_SENSORS

  attitude[PITCH] = getAngleEstimateFromAcc(PITCH);

  attitude[ROLL] = getAngleEstimateFromAcc(ROLL);

#else

  attitude[PITCH] = attitude[ROLL] = 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;

  driftComp[PITCH] = driftComp[ROLL] = yawGyroDrift = driftCompYaw = 0;

  correctionSum[PITCH] = correctionSum[ROLL] = 0;

  // Calibrate hardware.

  analog_setNeutral();

  // reset gyro integrals to acc guessing

  setStaticAttitudeAngles();

#ifdef USE_MK3MAG

  attitude_resetHeadingToMagnetic();

#endif

  // 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).

 * The rate variable end up in a range of about [-1024, 1023].

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

void getAnalogData(void) {

  uint8_t axis;

  analog_update();

  for (axis = PITCH; axis <= ROLL; axis++) {

    rate_PID[axis] = gyro_PID[axis] + driftComp[axis];

    rate_ATT[axis] = gyro_ATT[axis] + driftComp[axis];

    differential[axis] = gyroD[axis];

    averageAcc[axis] += acc[axis];

  }

  averageAccCount++;

  yawRate = yawGyro + driftCompYaw;

}

/*

 * 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 rollAngleInDegrees = attitude[ROLL] / GYRO_DEG_FACTOR_PITCHROLL;

  int16_t pitchAngleInDegrees = attitude[PITCH] / GYRO_DEG_FACTOR_PITCHROLL;

  int16_t cospitch = cos_360(pitchAngleInDegrees);

  int16_t cosroll = cos_360(rollAngleInDegrees);

  int16_t sinroll = sin_360(rollAngleInDegrees);

  ACRate[PITCH] = (((int32_t) rate_ATT[PITCH] * cosroll

      - (int32_t) yawRate * sinroll) >> LOG_MATH_UNIT_FACTOR);

  ACRate[ROLL] = rate_ATT[ROLL]

      + (((((int32_t) rate_ATT[PITCH] * sinroll + (int32_t) yawRate * cosroll)

          >> LOG_MATH_UNIT_FACTOR) * tan_360(pitchAngleInDegrees))

          >> LOG_MATH_UNIT_FACTOR);

  ACYawRate =

      ((int32_t) rate_ATT[PITCH] * sinroll + (int32_t) yawRate * cosroll)

          / cospitch;

}

// 480 usec with axis coupling - almost no time without.

void integrate(void) {

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

  uint8_t axis;

  if (staticParams.bitConfig & CFG_AXIS_COUPLING_ENABLED) {

    trigAxisCoupling();

  } else {

    ACRate[PITCH] = rate_ATT[PITCH];

    ACRate[ROLL] = rate_ATT[ROLL];

    ACYawRate = yawRate;

  }

  /*

   * Yaw

   * Calculate yaw gyro integral (~ to rotation angle)

   * Limit heading proportional to 0 deg to 360 deg

   */

  heading += ACYawRate;

  intervalWrap(&heading, YAWOVER360);

  headingError += ACYawRate;

  /*

   * Pitch axis integration and range boundary wrap.

   */

  for (axis = PITCH; axis <= ROLL; axis++) {

    attitude[axis] += ACRate[axis];

    if (attitude[axis] > PITCHROLLOVER180) {

      attitude[axis] -= PITCHROLLOVER360;

    } else if (attitude[axis] <= -PITCHROLLOVER180) {

      attitude[axis] += 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 a drift compensation

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

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

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

#define LOG_DIVIDER 12

#define DIVIDER (1L << LOG_DIVIDER)

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.

  uint8_t axis;

  int32_t temp;

  uint16_t ca = gyroActivity >> 8;

  debugOut.analog[14] = ca;

  uint8_t gyroActivityWeighted = ca / staticParams.rateTolerance;

  if (!gyroActivityWeighted) gyroActivityWeighted = 1;

  uint8_t accPart = staticParams.zerothOrderCorrection / gyroActivityWeighted;

  debugOut.analog[15] = gyroActivityWeighted;

  debugOut.digital[0] &= ~DEBUG_ACC0THORDER;

  debugOut.digital[1] &= ~DEBUG_ACC0THORDER;

  if (gyroActivityWeighted < 8) {

    debugOut.digital[0] |= DEBUG_ACC0THORDER;

  }

  if (gyroActivityWeighted <= 2) {

    debugOut.digital[1] |= DEBUG_ACC0THORDER;

  }

  /*

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

   */

  for (axis = PITCH; axis <= ROLL; axis++) {

    int32_t accDerived = getAngleEstimateFromAcc(axis);

    //debugOut.analog[9 + axis] = accDerived / (GYRO_DEG_FACTOR_PITCHROLL / 10);

    // 1000 * the correction amount that will be added to the gyro angle in next line.

    temp = attitude[axis];

    attitude[axis] = ((int32_t) (DIVIDER - accPart) * temp + (int32_t)accPart * accDerived) >> LOG_DIVIDER;

    correctionSum[axis] += attitude[axis] - temp;

  }

}

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

 * 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

 * DRIFTCORRECTION_TIME cycles are summed up. This number is

 * then divided by DRIFTCORRECTION_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. = 488/2

#define DRIFTCORRECTION_TIME 256L

void driftCorrection(void) {

  static int16_t timer = DRIFTCORRECTION_TIME;

  int16_t deltaCorrection;

  int16_t round;

  uint8_t axis;

  if (!--timer) {

    timer = DRIFTCORRECTION_TIME;

    for (axis = PITCH; axis <= ROLL; axis++) {

      // Take the sum of corrections applied, add it to delta

      if (correctionSum[axis] >= 0)

        round = DRIFTCORRECTION_TIME / 2;

      else

        round = -DRIFTCORRECTION_TIME / 2;

      deltaCorrection = (correctionSum[axis] + round) / DRIFTCORRECTION_TIME;

      // Add the delta to the compensation. So positive delta means, gyro should have higher value.

      driftComp[axis] += deltaCorrection / staticParams.driftCompDivider;

      CHECK_MIN_MAX(driftComp[axis], -staticParams.driftCompLimit, staticParams.driftCompLimit);

      // DebugOut.Analog[11 + axis] = correctionSum[axis];

      // DebugOut.Analog[16 + axis] = correctionSum[axis];

      // debugOut.analog[28 + axis] = driftComp[axis];

      correctionSum[axis] = 0;

    }

  }

}

/*

void calculateAccVector(void) {

  int16_t temp;

  temp = filteredAcc[0] >> 3;

  accVector = temp * temp;

  temp = filteredAcc[1] >> 3;

  accVector += temp * temp;

  temp = filteredAcc[2] >> 3;

  accVector += temp * temp;

}

*/

#ifdef USE_MK3MAG

void attitude_resetHeadingToMagnetic(void) {

  if (commands_isCalibratingCompass())

    return;

  // Compass is off, skip.

  if (!(staticParams.bitConfig & CFG_COMPASS_ENABLED))

      return;

  // Compass is invalid, skip.

  if (magneticHeading < 0)

    return;

  heading = (int32_t) magneticHeading * GYRO_DEG_FACTOR_YAW;

  //targetHeading = heading;

  headingError = 0;

}

void correctHeadingToMagnetic(void) {

  int32_t error;

  if (commands_isCalibratingCompass()) {

    //debugOut.analog[30] = -1;

    return;

  }

  // Compass is off, skip.

  // Naaah this is assumed.

  // if (!(staticParams.bitConfig & CFG_COMPASS_ACTIVE))

  //     return;

  // Compass is invalid, skip.

  if (magneticHeading < 0) {

    //debugOut.analog[30] = -2;

    return;

  }

  // Spinning fast, skip

  if (abs(yawRate) > 128) {

    // debugOut.analog[30] = -3;

    return;

  }

  // Otherwise invalidated, skip

  if (ignoreCompassTimer) {

    ignoreCompassTimer--;

    //debugOut.analog[30] = -4;

    return;

  }

  //debugOut.analog[30] = magneticHeading;

  // TODO: Find computational cost of this.

  error = ((int32_t)magneticHeading*GYRO_DEG_FACTOR_YAW - heading);

  if (error <= -YAWOVER180) error += YAWOVER360;

  else if (error > YAWOVER180) error -= YAWOVER360;

  // We only correct errors larger than the resolution of the compass, or else we would keep rounding the

  // better resolution of the gyros to the worse resolution of the compass all the time.

  // The correction should really only serve to compensate for gyro drift.

  if(abs(error) < GYRO_DEG_FACTOR_YAW) return;

  int32_t correction = (error * staticParams.compassYawCorrection) >> 8;

  //debugOut.analog[30] = correction;

  debugOut.digital[0] &= ~DEBUG_COMPASS;

  debugOut.digital[1] &= ~DEBUG_COMPASS;

  if (correction > 0) {

          debugOut.digital[0] ^= DEBUG_COMPASS;

  } else if (correction < 0) {

          debugOut.digital[1] ^= DEBUG_COMPASS;

  }

  // The correction is added both to current heading (the direction in which the copter thinks it is pointing)

  // and to the heading error (the angle of yaw that the copter is off the set heading).

  heading += correction;

  headingError += correction;

  intervalWrap(&heading, YAWOVER360);

  // If we want a transparent flight wrt. compass correction (meaning the copter does not change attitude all

  // when the compass corrects the heading - it only corrects numbers!) we want to add:

  // This will however cause drift to remain uncorrected!

  // headingError += correction;

  //debugOut.analog[29] = 0;

}

#endif

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

 * Main procedure.

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

void calculateFlightAttitude(void) {

  getAnalogData();

  // calculateAccVector();

  integrate();

#ifdef ATTITUDE_USE_ACC_SENSORS

  correctIntegralsByAcc0thOrder();

  driftCorrection();

#endif

  // We are done reading variables from the analog module.

  // Interrupt-driven sensor reading may restart.

  startAnalogConversionCycle();

#ifdef USE_MK3MAG

  if (staticParams.bitConfig & CFG_COMPASS_ENABLED) {

    correctHeadingToMagnetic();

  }

#endif

}