Subversion Repositories FlightCtrl

// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Copyright (c) 04.2007 Holger Buss
// + Nur für den privaten Gebrauch
// + www.MikroKopter.com
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
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// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
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// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
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// +     from this software without specific prior written permission.
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// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
#include <inttypes.h>
#include <stdlib.h>
//#include "mymath.h"
#include "timer0.h"
#include "uart0.h"
#include "rc.h"
#include "eeprom.h"

typedef enum
  {
    GPS_FLIGHT_MODE_UNDEF,
    GPS_FLIGHT_MODE_FREE,
    GPS_FLIGHT_MODE_AID,
    GPS_FLIGHT_MODE_HOME,
  } FlightMode_t;

#define GPS_POSINTEGRAL_LIMIT 32000
#define GPS_STICK_LIMIT         45              // limit of gps stick control to avoid critical flight attitudes
#define GPS_P_LIMIT                     25


typedef struct
{
  int32_t Longitude;
  int32_t Latitude;
  int32_t Altitude;
  Status_t Status;
} GPS_Pos_t;

// GPS coordinates for hold position
GPS_Pos_t HoldPosition  = {0,0,0,INVALID};
// GPS coordinates for home position
GPS_Pos_t HomePosition  = {0,0,0,INVALID};
// the current flight mode
FlightMode_t FlightMode = GPS_FLIGHT_MODE_UNDEF;


// ---------------------------------------------------------------------------------
void GPS_UpdateParameter(void) {
  static FlightMode_t FlightModeOld = GPS_FLIGHT_MODE_UNDEF;
 
  if((RC_Quality < 100) || (MKFlags & MKFLAG_EMERGENCY_LANDING)) {
    FlightMode = GPS_FLIGHT_MODE_FREE;
  } else {
    if     (dynamicParams.NaviGpsModeControl <  50) FlightMode = GPS_FLIGHT_MODE_AID;
    else if(dynamicParams.NaviGpsModeControl < 180) FlightMode = GPS_FLIGHT_MODE_FREE;
    else                                          FlightMode = GPS_FLIGHT_MODE_HOME;
  }

  if (FlightMode != FlightModeOld) {
    BeepTime = 100;
  }
  FlightModeOld = FlightMode;
}

// ---------------------------------------------------------------------------------
// This function defines a good GPS signal condition
uint8_t GPS_IsSignalOK(void) {
  static uint8_t GPSFix = 0;
  if( (GPSInfo.status != INVALID)  && (GPSInfo.satfix == SATFIX_3D) && (GPSInfo.flags & FLAG_GPSFIXOK) && ((GPSInfo.satnum >= staticParams.NaviGpsMinSat) || GPSFix)) {
    GPSFix = 1;
    return 1;
  }
  else return (0);
}

// ---------------------------------------------------------------------------------
// rescale xy-vector length to  limit
uint8_t GPS_LimitXY(int32_t *x, int32_t *y, int32_t limit) {
  uint8_t retval = 0;
  int32_t len;
  len = (int32_t)c_sqrt(*x * *x + *y * *y);
  if (len > limit) {
    // normalize control vector components to the limit
    *x  = (*x  * limit) / len;
    *y  = (*y  * limit) / len;
    retval = 1;
  }
  return(retval);
}

// checks nick and roll sticks for manual control
uint8_t GPS_IsManualControlled(void) {
  if ((abs(PPM_in[staticParams.ChannelAssignment[CH_NICK]]) < staticParams.NaviStickThreshold) && (abs(PPM_in[staticParams.ChannelAssignment[CH_ROLL]]) < staticParams.NaviStickThreshold)) return 0;
  else return 1;
}

// set given position to current gps position
uint8_t GPS_SetCurrPosition(GPS_Pos_t * pGPSPos) {
  uint8_t retval = 0;
  if(pGPSPos == NULL) return(retval);   // bad pointer

  if(GPS_IsSignalOK()) {        // is GPS signal condition is fine
    pGPSPos->Longitude  = GPSInfo.longitude;
    pGPSPos->Latitude   = GPSInfo.latitude;
    pGPSPos->Altitude   = GPSInfo.altitude;
    pGPSPos->Status     = NEWDATA;
    retval = 1;
  } else {      // bad GPS signal condition
    pGPSPos->Status = INVALID;
    retval = 0;
  }
  return(retval);
}

// clear position
uint8_t GPS_ClearPosition(GPS_Pos_t * pGPSPos) {
  uint8_t retval = 0;
  if(pGPSPos == NULL)
    return retval;      // bad pointer
  else {
    pGPSPos->Longitude  = 0;
    pGPSPos->Latitude   = 0;
    pGPSPos->Altitude   = 0;
    pGPSPos->Status     = INVALID;
    retval = 1;
  }
  return (retval);
}

// disable GPS control sticks
void GPS_Neutral(void) {
  GPSStickNick = 0;
  GPSStickRoll = 0;
}

// calculates the GPS control stick values from the deviation to target position
// if the pointer to the target positin is NULL or is the target position invalid
// then the P part of the controller is deactivated.
void GPS_PIDController(GPS_Pos_t *pTargetPos) {
  static int32_t PID_Nick, PID_Roll;
  int32_t coscompass, sincompass;
  int32_t GPSPosDev_North, GPSPosDev_East; // Position deviation in cm
  int32_t P_North = 0, D_North = 0, P_East = 0, D_East = 0, I_North = 0, I_East = 0;
  int32_t PID_North = 0, PID_East = 0;
  static int32_t cos_target_latitude = 1;
  static int32_t GPSPosDevIntegral_North = 0, GPSPosDevIntegral_East = 0;
  static GPS_Pos_t *pLastTargetPos = 0;

  // if GPS data and Compass are ok
  if( GPS_IsSignalOK() && (CompassHeading >= 0)) {
    if(pTargetPos != NULL) // if there is a target position
      {
        if(pTargetPos->Status != INVALID) // and the position data are valid
          {
            // if the target data are updated or the target pointer has changed
            if ((pTargetPos->Status != PROCESSED) || (pTargetPos != pLastTargetPos) )
              {
                // reset error integral
                GPSPosDevIntegral_North = 0;
                GPSPosDevIntegral_East = 0;
                // recalculate latitude projection
                cos_target_latitude = (int32_t)c_cos_8192((int16_t)(pTargetPos->Latitude/10000000L));
                // remember last target pointer
                pLastTargetPos = pTargetPos;
                // mark data as processed
                pTargetPos->Status = PROCESSED;
              }
            // calculate position deviation from latitude and longitude differences
            GPSPosDev_North = (GPSInfo.latitude - pTargetPos->Latitude); // to calculate real cm we would need *111/100 additionally
            GPSPosDev_East  = (GPSInfo.longitude - pTargetPos->Longitude); // to calculate real cm we would need *111/100 additionally
            // calculate latitude projection
            GPSPosDev_East  *= cos_target_latitude;
            GPSPosDev_East /= 8192;
          }
        else // no valid target position available
          {
            // reset error
            GPSPosDev_North = 0;
            GPSPosDev_East = 0;
            // reset error integral
            GPSPosDevIntegral_North = 0;
            GPSPosDevIntegral_East = 0;
          }
      }
    else // no target position available
      {
        // reset error
        GPSPosDev_North = 0;
        GPSPosDev_East = 0;
        // reset error integral
        GPSPosDevIntegral_North = 0;
        GPSPosDevIntegral_East = 0;
      }
   
    //Calculate PID-components of the controller
   
    // D-Part
    D_North = ((int32_t)dynamicParams.NaviGpsD * GPSInfo.velnorth)/512;
    D_East =  ((int32_t)dynamicParams.NaviGpsD * GPSInfo.veleast)/512;
   
    // P-Part
    P_North = ((int32_t)dynamicParams.NaviGpsP * GPSPosDev_North)/2048;
    P_East =  ((int32_t)dynamicParams.NaviGpsP * GPSPosDev_East)/2048;
   
    // I-Part
    I_North = ((int32_t)dynamicParams.NaviGpsI * GPSPosDevIntegral_North)/8192;
    I_East =  ((int32_t)dynamicParams.NaviGpsI * GPSPosDevIntegral_East)/8192;
   
    // combine P & I
    PID_North = P_North + I_North;
    PID_East  = P_East  + I_East;
    if(!GPS_LimitXY(&PID_North, &PID_East, GPS_P_LIMIT))
      {
        GPSPosDevIntegral_North += GPSPosDev_North/16;
        GPSPosDevIntegral_East  += GPSPosDev_East/16;
        GPS_LimitXY(&GPSPosDevIntegral_North, &GPSPosDevIntegral_East, GPS_POSINTEGRAL_LIMIT);
      }
   
    // combine PI- and D-Part
    PID_North += D_North;
    PID_East  += D_East;
   
    // scale combination with gain.
    PID_North = (PID_North * (int32_t)dynamicParams.NaviGpsGain) / 100;
    PID_East  = (PID_East  * (int32_t)dynamicParams.NaviGpsGain) / 100;

    // GPS to nick and roll settings
    // A positive nick angle moves head downwards (flying forward).
    // A positive roll angle tilts left side downwards (flying left).
    // If compass heading is 0 the head of the copter is in north direction.
    // A positive nick angle will fly to north and a positive roll angle will fly to west.
    // In case of a positive north deviation/velocity the
    // copter should fly to south (negative nick).
    // In case of a positive east position deviation and a positive east velocity the
    // copter should fly to west (positive roll).
    // The influence of the GPSStickNick and GPSStickRoll variable is contrarily to the stick values
    // in the flight.c. Therefore a positive north deviation/velocity should result in a positive
    // GPSStickNick and a positive east deviation/velocity should result in a negative GPSStickRoll.
   
    coscompass = (int32_t)c_cos_8192(YawGyroHeading / GYRO_DEG_FACTOR);
    sincompass = (int32_t)c_sin_8192(YawGyroHeading / GYRO_DEG_FACTOR);
    PID_Nick =   (coscompass * PID_North + sincompass * PID_East) / 8192;
    PID_Roll  =  (sincompass * PID_North - coscompass * PID_East) / 8192;
   
    // limit resulting GPS control vector
    GPS_LimitXY(&PID_Nick, &PID_Roll, GPS_STICK_LIMIT);
   
    GPSStickNick = (int16_t)PID_Nick;
    GPSStickRoll = (int16_t)PID_Roll;
  }
  else // invalid GPS data or bad compass reading
    {
      GPS_Neutral(); // do nothing
      // reset error integral
      GPSPosDevIntegral_North = 0;
      GPSPosDevIntegral_East = 0;
    }
}

void GPS_Main(void) {
  static uint8_t GPS_P_Delay = 0;
  static uint16_t beep_rythm = 0;

  GPS_UpdateParameter();

  // store home position if start of flight flag is set
  if(MKFlags & MKFLAG_CALIBRATE) {
    if(GPS_SetCurrPosition(&HomePosition)) BeepTime = 700;
  }
 
  switch(GPSInfo.status) {
  case INVALID:  // invalid gps data
    GPS_Neutral();
    if(FlightMode != GPS_FLIGHT_MODE_FREE) {
      BeepTime = 100; // beep if signal is neccesary
    }
    break;
  case PROCESSED: // if gps data are already processed do nothing
    // downcount timeout
    if(GPSTimeout) GPSTimeout--;
    // if no new data arrived within timeout set current data invalid
    // and therefore disable GPS
    else
      {
        GPS_Neutral();
          GPSInfo.status = INVALID;
      }
    break;
  case NEWDATA: // new valid data from gps device
    // if the gps data quality is good
    beep_rythm++;
   
    if (GPS_IsSignalOK())
      {
        switch(FlightMode) // check what's to do
          {
          case GPS_FLIGHT_MODE_FREE:
            // update hold position to current gps position
            GPS_SetCurrPosition(&HoldPosition); // can get invalid if gps signal is bad
            // disable gps control
            GPS_Neutral();
            break;
           
          case GPS_FLIGHT_MODE_AID:
            if(HoldPosition.Status != INVALID)
              {
                if( GPS_IsManualControlled() ) // MK controlled by user
                  {
                    // update hold point to current gps position
                    GPS_SetCurrPosition(&HoldPosition);
                    // disable gps control
                    GPS_Neutral();
                    GPS_P_Delay = 0;
                  }
                else // GPS control active
                  {
                    if(GPS_P_Delay < 7)
                      { // delayed activation of P-Part for 8 cycles (8*0.25s = 2s)
                        GPS_P_Delay++;
                        GPS_SetCurrPosition(&HoldPosition); // update hold point to current gps position
                        GPS_PIDController(NULL); // activates only the D-Part
                      }
                    else GPS_PIDController(&HoldPosition);// activates the P&D-Part
                  }
              }
            else // invalid Hold Position
              {  // try to catch a valid hold position from gps data input
                GPS_SetCurrPosition(&HoldPosition);
                GPS_Neutral();
              }
            break;
           
          case GPS_FLIGHT_MODE_HOME:
            if(HomePosition.Status != INVALID)
              {
                // update hold point to current gps position
                // to avoid a flight back if home comming is deactivated
                GPS_SetCurrPosition(&HoldPosition);
                if( GPS_IsManualControlled() ) // MK controlled by user
                  {
                    GPS_Neutral();
                  }
                else // GPS control active
                  {
                    GPS_PIDController(&HomePosition);
                  }
              }
            else // bad home position
              {
                BeepTime = 50; // signal invalid home position
                // try to hold at least the position as a fallback option
               
                if (HoldPosition.Status != INVALID)
                  {
                    if( GPS_IsManualControlled() ) // MK controlled by user
                      {
                        GPS_Neutral();
                      }
                    else // GPS control active
                      {
                        GPS_PIDController(&HoldPosition);
                      }
                  }
                else
                  { // try to catch a valid hold position
                    GPS_SetCurrPosition(&HoldPosition);
                    GPS_Neutral();
                  }
              }
            break; // eof TSK_HOME
          default: // unhandled task
            GPS_Neutral();
            break; // eof default
          } // eof switch GPS_Task
      } // eof gps data quality is good
    else // gps data quality is bad
      { // disable gps control
        GPS_Neutral();
        if(FlightMode != GPS_FLIGHT_MODE_FREE)
          {
            // beep if signal is not sufficient
            if(!(GPSInfo.flags & FLAG_GPSFIXOK) && !(beep_rythm % 5)) BeepTime = 100;
            else if (GPSInfo.satnum < staticParams.NaviGpsMinSat && !(beep_rythm % 5)) BeepTime = 10;
          }
      }
      // set current data as processed to avoid further calculations on the same gps data
    GPSInfo.status = PROCESSED;
    break;
  } // eof GPSInfo.status
}