WebSVN - FlightCtrl - Diff - Rev 2051 and 2052 - /branches/dongfang_FC


#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;
 
/************************************************************************
 * 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;
 
  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_ACTIVE) {
    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;
 
  debugOut.analog[27] = heading / 100;
 
  /*
   * 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.
 ************************************************************************/
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;
 
  uint8_t ca = controlActivity >> 8;
  uint8_t highControlActivity = (ca > staticParams.maxControlActivity);
 
  if (highControlActivity) {
    debugOut.digital[1] |= DEBUG_ACC0THORDER;
  } else {
    debugOut.digital[1] &= ~DEBUG_ACC0THORDER;
  }
 
  if (accVector <= dynamicParams.maxAccVector) {
    debugOut.digital[0] &= ~DEBUG_ACC0THORDER;
 
    uint8_t permilleAcc = staticParams.zerothOrderCorrection;
    int32_t accDerived;
 
    /*
     if ((controlYaw < -64) || (controlYaw > 64)) { // reduce further if yaw stick is active
     permilleAcc /= 2;
     debugFullWeight = 0;
     }
 
     if ((maxControl[PITCH] > 64) || (maxControl[ROLL] > 64)) { // reduce effect during stick commands. Replace by controlActivity.
     permilleAcc /= 2;
     debugFullWeight = 0;
     */
 
    if (highControlActivity) { // reduce effect during stick control activity
      permilleAcc /= 4;
      if (controlActivity > staticParams.maxControlActivity * 2) { // reduce effect during stick control activity
        permilleAcc /= 4;
      }
    }
 
    /*
     * Add to each sum: The amount by which the angle is changed just below.
     */
    for (axis = PITCH; axis <= ROLL; axis++) {
      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) (1000L - permilleAcc) * temp
          + (int32_t) permilleAcc * accDerived) / 1000L;
      correctionSum[axis] += attitude[axis] - temp;
    }
  } else {
    debugOut.analog[9] = 0;
    debugOut.analog[10] = 0;
    // experiment: Kill drift compensation updates when not flying smooth.
    // correctionSum[PITCH] = correctionSum[ROLL] = 0;
    debugOut.digital[0] |= DEBUG_ACC0THORDER;
  }
}
 
/************************************************************************
 * 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;
  //debugOut.analog[18] = accVector;
}
 
#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;
 
  debugOut.digital[0] ^= DEBUG_COMPASS;
}
 
void correctHeadingToMagnetic(void) {
  int32_t error;
 
  if (commands_isCalibratingCompass()) {
    debugOut.analog[29] = 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[29] = 2;
    return;
  }
 
  // Spinning fast, skip
  if (abs(yawRate) > 128) {
    debugOut.analog[29] = 3;
    return;
  }
 
  // Otherwise invalidated, skip
  if (ignoreCompassTimer) {
    ignoreCompassTimer--;
    debugOut.analog[29] = 4;
    return;
  }
 
  // 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;
 
  // The correction is added both to current heading (the direction in which the copter thinks it is pointing)
  // and to the target heading (the direction to which it maneuvers to point). That means, this correction has
  // no effect on control at all!!! It only has effect on the values of the two variables. However, these values
  // could have effect on control elsewhere, like in compassControl.c .
  heading += 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 | CFG_GPS_ENABLED)) {
    correctHeadingToMagnetic();
  }
#endif
}
 
/*
 * 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
 driftCompPitch = dynamicParams.UserParam7 - 128;
 driftCompRoll = dynamicParams.UserParam8 - 128;
 } else {
 // use the sampled value (does not seem to work so well....)
 driftCompPitch = savedDynamicOffsetPitch = -dynamicCalPitch / dynamicCalCount;
 driftCompRoll = savedDynamicOffsetRoll = -dynamicCalRoll / dynamicCalCount;
 driftCompYaw = -dynamicCalYaw / dynamicCalCount;
 }
 
 // keep resetting these meanwhile, to avoid accumulating errors.
 setStaticAttitudeIntegrals();
 yawAngle = 0;
 }
 */
 
Subversion Repositories FlightCtrl

(root)/branches/dongfang_FC_rewrite/attitude.c @ 2052 - Rev 2051 → 2052
