Subversion Repositories FlightCtrl

// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Copyright (c) 04.2007 Holger Buss
// + Nur für den privaten Gebrauch
// + www.MikroKopter.com
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Es gilt für das gesamte Projekt (Hardware, Software, Binärfiles, Sourcecode und Dokumentation),
// + dass eine Nutzung (auch auszugsweise) nur für den privaten (nicht-kommerziellen) Gebrauch zulässig ist.
// + Sollten direkte oder indirekte kommerzielle Absichten verfolgt werden, ist mit uns (info@mikrokopter.de) Kontakt
// + bzgl. der Nutzungsbedingungen aufzunehmen.
// + Eine kommerzielle Nutzung ist z.B.Verkauf von MikroKoptern, Bestückung und Verkauf von Platinen oder Bausätzen,
// + Verkauf von Luftbildaufnahmen, usw.
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Werden Teile des Quellcodes (mit oder ohne Modifikation) weiterverwendet oder veröffentlicht,
// + unterliegen sie auch diesen Nutzungsbedingungen und diese Nutzungsbedingungen incl. Copyright müssen dann beiliegen
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Sollte die Software (auch auszugesweise) oder sonstige Informationen des MikroKopter-Projekts
// + auf anderen Webseiten oder sonstigen Medien veröffentlicht werden, muss unsere Webseite "http://www.mikrokopter.de"
// + eindeutig als Ursprung verlinkt werden
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Keine Gewähr auf Fehlerfreiheit, Vollständigkeit oder Funktion
// + Benutzung auf eigene Gefahr
// + Wir übernehmen keinerlei Haftung für direkte oder indirekte Personen- oder Sachschäden
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Die Portierung der Software (oder Teile davon) auf andere Systeme (ausser der Hardware von www.mikrokopter.de) ist nur
// + mit unserer Zustimmung zulässig
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Die Funktion printf_P() unterliegt ihrer eigenen Lizenz und ist hiervon nicht betroffen
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Redistributions of source code (with or without modifications) must retain the above copyright notice,
// + this list of conditions and the following disclaimer.
// +   * Neither the name of the copyright holders nor the names of contributors may be used to endorse or promote products derived
// +     from this software without specific prior written permission.
// +   * The use of this project (hardware, software, binary files, sources and documentation) is only permittet
// +     for non-commercial use (directly or indirectly)
// +     Commercial use (for excample: selling of MikroKopters, selling of PCBs, assembly, ...) is only permitted
// +     with our written permission
// +   * If sources or documentations are redistributet on other webpages, out webpage (http://www.MikroKopter.de) must be
// +     clearly linked as origin
// +   * porting to systems other than hardware from www.mikrokopter.de is not allowed
// +  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// +  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// +  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// +  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// +  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// +  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// +  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// +  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN// +  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// +  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// +  POSSIBILITY OF SUCH DAMAGE.
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

/************************************************************************/
/* 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 rate[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 angle[2], 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)

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

/*
 * Experiment: Compensating for dynamic-induced gyro biasing.
 */
int16_t dynamicOffset[2] = {0,0}, 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 getAngleEstimateFromAcc(uint8_t axis) {
  return GYRO_ACC_FACTOR * (int32_t)filteredAcc[axis];
}

void setStaticAttitudeAngles(void) {
#ifdef ATTITUDE_USE_ACC_SENSORS
  angle[PITCH] = getAngleEstimateFromAcc(PITCH);
  angle[ROLL] = getAngleEstimateFromAcc(ROLL);
#else
  angle[PITCH] = angle[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;

  dynamicOffset[PITCH] = dynamicOffset[ROLL] = 0;
  correctionSum[PITCH] = correctionSum[ROLL] = 0;
 
  // Calibrate hardware.
  analog_calibrate();

  // reset gyro readings
  rate[PITCH] = rate[ROLL] = 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).
 * The rate variable end up in a range of about [-1024, 1023].
 * When scaled down by CONTROL_SCALING, the interval is about [-256, 256].
 *************************************************************************/
void getAnalogData(void) {
  uint8_t axis;
 
  for (axis=PITCH; axis <=ROLL; axis++) {
    rate_PID[axis]     = (gyro_PID[axis] + dynamicOffset[axis]) / HIRES_GYRO_INTEGRATION_FACTOR;
    rate[axis]         = (gyro_ATT[axis] + dynamicOffset[axis]) / HIRES_GYRO_INTEGRATION_FACTOR;
    differential[axis] = gyroD[axis];
  }
 
  yawRate = yawGyro + dynamicOffsetYaw;

  // We are done reading variables from the analog module.
  // Interrupt-driven sensor reading may restart.
  analogDataReady = 0;
  analog_start();
}

/*
 * 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(angle[PITCH]);
  int16_t cosroll =  int_cos(angle[ROLL]);
  int16_t sinroll =  int_sin(angle[ROLL]);
  int16_t tanpitch = int_tan(angle[PITCH]);
#define ANTIOVF 1024
  ACRate[PITCH] =             ((int32_t) rate[PITCH] * cosroll - (int32_t)yawRate * sinroll) / (int32_t)MATH_UNIT_FACTOR;
  ACRate[ROLL] = rate[ROLL] + (((int32_t)rate[PITCH] * sinroll / ANTIOVF * tanpitch + (int32_t)yawRate * int_cos(angle[ROLL]) / ANTIOVF * tanpitch) / ((int32_t)MATH_UNIT_FACTOR / ANTIOVF * MATH_UNIT_FACTOR));
  ACYawRate =                 ((int32_t) rate[PITCH] * sinroll) / cospitch + ((int32_t)yawRate * cosroll) / cospitch;
}

void integrate(void) {
  // First, perform axis coupling. If disabled xxxRate is just copied to ACxxxRate.
  uint8_t axis;
 
  if(!looping && (staticParams.GlobalConfig & CFG_AXIS_COUPLING_ACTIVE)) {
    // The rotary rate limiter bit is abused for selecting axis coupling algorithm instead.
    trigAxisCoupling();    
  } else {
    ACRate[PITCH] = rate[PITCH];
    ACRate[ROLL]  = rate[ROLL];
    ACYawRate = yawRate;
  }

  /*
   * 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.
   */
  for (axis=PITCH; axis<=ROLL; axis++) {
    angle[axis] += ACRate[axis];
    if(angle[axis] > PITCHROLLOVER180) {
      angle[axis] -= PITCHROLLOVER360;
    } else if (angle[axis] <= -PITCHROLLOVER180) {
      angle[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 correction;
  if(!looping && acc[Z] >= -dynamicParams.UserParams[7] && acc[Z] <= 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 accDerived;
   
    if((maxControl[PITCH] > 64) || (maxControl[ROLL] > 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.
     */
    for (axis=PITCH; axis<=ROLL; axis++) {
      accDerived = getAngleEstimateFromAcc(axis);
      DebugOut.Analog[9 + axis] = (10 * accDerived) / GYRO_DEG_FACTOR_PITCHROLL;
     
      // 1000 * the correction amount that will be added to the gyro angle in next line.
      correction = angle[axis]; //(permilleAcc * (accDerived - angle[axis])) / 1000;
      angle[axis] = ((int32_t)(1000 - permilleAcc) * angle[axis] + (int32_t)permilleAcc * accDerived) / 1000L;

      correctionSum[axis] += angle[axis] - correction;
   
      // There should not be a risk of overflow here, since the integrals do not exceed a few 100000.
      // change = ((1000 - permilleAcc) * angle[axis] + permilleAcc * accDerived) / 1000 - angle[axis]
      // = (1000 * angle[axis] - permilleAcc * angle[axis] + permilleAcc * accDerived) / 1000 - angle[axis]
      // = (- permilleAcc * angle[axis] + permilleAcc * accDerived) / 1000
      // = permilleAcc * (accDerived - angle[axis]) / 1000
     
      // Experiment: Do not acutally apply the correction. See if drift compensation does that.
      // angle[axis] += correction / 1000;
    }
       
    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
 * 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;
  uint8_t axis;
  if (! --timer) {
    timer = DRIFTCORRECTION_TIME;
    for (axis=PITCH; axis<=ROLL; axis++) {
      // Take the sum of corrections applied, add it to delta
      deltaCorrection = ((correctionSum[axis] + DRIFTCORRECTION_TIME / 2) * HIRES_GYRO_INTEGRATION_FACTOR) / DRIFTCORRECTION_TIME;
      // Add the delta to the compensation. So positive delta means, gyro should have higher value.
      dynamicOffset[axis] += deltaCorrection / staticParams.GyroAccTrim;
      CHECK_MIN_MAX(dynamicOffset[axis], -staticParams.DriftComp, staticParams.DriftComp);
      DebugOut.Analog[11 + axis] = correctionSum[axis];
      DebugOut.Analog[28 + axis] = dynamicOffset[axis];
      correctionSum[axis] = 0;
    }
  }
}

/************************************************************************
 * Main procedure.
 ************************************************************************/
void calculateFlightAttitude(void) {  
  getAnalogData();
  integrate();
 
  DebugOut.Analog[6] = ACRate[PITCH];
  DebugOut.Analog[7] = ACRate[ROLL];
  DebugOut.Analog[8] = ACYawRate;
 
  DebugOut.Analog[3] = rate_PID[PITCH];
  DebugOut.Analog[4] = rate_PID[ROLL];
  DebugOut.Analog[5] = yawRate;
 
#ifdef ATTITUDE_USE_ACC_SENSORS
  correctIntegralsByAcc0thOrder();
  driftCorrection();
#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;
  }
*/