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.
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// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
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// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
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// + Redistributions of source code (with or without modifications) must retain the above copyright notice,
// + this list of conditions and the following disclaimer.
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// +     from this software without specific prior written permission.
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// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
#include <inttypes.h>
#include <stdlib.h>
#include "ubx.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
}