Subversion Repositories FlightCtrl

// Navigation with a GPS directly attached to the FC's UART1.

#include <inttypes.h>
#include <stdlib.h>
#include <stddef.h>
//#include "mymath.h"
//#include "timer0.h"
//#include "uart1.h"
//#include "rc.h"
//#include "eeprom.h"
#include "ubx.h"
#include "configuration.h"
#include "controlMixer.h"
#include "output.h"
#include "isqrt.h"
#include "attitude.h"
#include "dongfangMath.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_updateFlightMode(void) {
  static FlightMode_t flightModeOld = GPS_FLIGHT_MODE_UNDEF;

  if (controlMixer_getSignalQuality() <= SIGNAL_BAD
      || MKFlags & MKFLAG_EMERGENCY_FLIGHT) {
    flightMode = GPS_FLIGHT_MODE_FREE;
  } else {
    if (dynamicParams.directGPSMode < 50)
      flightMode = GPS_FLIGHT_MODE_AID;
    else if (dynamicParams.directGPSMode < 180)
      flightMode = GPS_FLIGHT_MODE_FREE;
    else
      flightMode = GPS_FLIGHT_MODE_HOME;
  }

  if (flightMode != flightModeOld) {
    beep(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.GPSMininumSatellites) || 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) {
  int32_t len;
  len = isqrt32(*x * *x + *y * *y);
  if (len > limit) {
    // normalize control vector components to the limit
    *x = (*x * limit) / len;
    *y = (*y * limit) / len;
    return 1;
  }
  return 0;
}

// checks nick and roll sticks for manual control
uint8_t GPS_isManuallyControlled(int16_t* naviSticks) {
  if (naviSticks[CONTROL_PITCH] < staticParams.naviStickThreshold
      && naviSticks[CONTROL_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);
}

// 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, int16_t* sticks) {
  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() && (magneticHeading >= 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 = int_cos((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 >>= MATH_UNIT_FACTOR_LOG;
      } 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) staticParams.naviD * GPSInfo.velnorth) / 512;
    D_East = ((int32_t) staticParams.naviD * GPSInfo.veleast) / 512;

    // P-Part
    P_North = ((int32_t) staticParams.naviP * GPSPosDev_North) / 2048;
    P_East = ((int32_t) staticParams.naviP * GPSPosDev_East) / 2048;

    // I-Part
    I_North = ((int32_t) staticParams.naviI * GPSPosDevIntegral_North)
        / 8192;
    I_East = ((int32_t) staticParams.naviI * 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.
    // dongfang: Lets not do that. P I and D can be scaled instead.
    // PID_North = (PID_North * (int32_t) staticParams.NaviGpsGain) / 100;
    // PID_East = (PID_East * (int32_t) staticParams.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 = int_cos(yawGyroHeading / GYRO_DEG_FACTOR_YAW);
    sincompass = int_sin(yawGyroHeading / GYRO_DEG_FACTOR_YAW);
    PID_Nick = (coscompass * PID_North + sincompass * PID_East) >> MATH_UNIT_FACTOR_LOG;
    PID_Roll = (sincompass * PID_North - coscompass * PID_East) >> MATH_UNIT_FACTOR_LOG;

    // limit resulting GPS control vector
    GPS_limitXY(&PID_Nick, &PID_Roll, GPS_STICK_LIMIT);

    sticks[CONTROL_PITCH] += (int16_t) PID_Nick;
    sticks[CONTROL_ROLL] += (int16_t) PID_Roll;
  } else { // invalid GPS data or bad compass reading
    // reset error integral
    GPSPosDevIntegral_North = 0;
    GPSPosDevIntegral_East = 0;
  }
}

void navigation_periodicTask(int16_t* sticks) {
  static uint8_t GPS_P_Delay = 0;
  static uint16_t beep_rythm = 0;

  GPS_updateFlightMode();

  // store home position if start of flight flag is set
  if (MKFlags & MKFLAG_CALIBRATE) {
    if (GPS_setCurrPosition(&homePosition))
      beep(700);
  }

  switch (GPSInfo.status) {
  case INVALID: // invalid gps data
    if (flightMode != GPS_FLIGHT_MODE_FREE) {
      beep(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 {
      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
        break;

      case GPS_FLIGHT_MODE_AID:
        if (holdPosition.status != INVALID) {
          if (GPS_isManuallyControlled(sticks)) { // MK controlled by user
            // update hold point to current gps position
            GPS_setCurrPosition(&holdPosition);
            // disable gps control
            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, sticks); // activates only the D-Part
            } else
              GPS_PIDController(&holdPosition, sticks); // activates the P&D-Part
          }
        } else // invalid Hold Position
        { // try to catch a valid hold position from gps data input
          GPS_setCurrPosition(&holdPosition);
        }
        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_isManuallyControlled(sticks)) // MK controlled by user
          {
          } else {// GPS control active
            GPS_PIDController(&homePosition, sticks);
          }
        } else {
          // bad home position
          beep(50); // signal invalid home position
          // try to hold at least the position as a fallback option

          if (holdPosition.status != INVALID) {
            if (GPS_isManuallyControlled(sticks)) {
              // MK controlled by user
            } else {
              // GPS control active
              GPS_PIDController(&holdPosition, sticks);
            }
          } else { // try to catch a valid hold position
            GPS_setCurrPosition(&holdPosition);
          }
        }
        break; // eof TSK_HOME
      default: // unhandled task
        break; // eof default
      } // eof switch GPS_Task
    } // eof gps data quality is good
    else // gps data quality is bad
    { // disable gps control
      if (flightMode != GPS_FLIGHT_MODE_FREE) {
        // beep if signal is not sufficient
        if (!(GPSInfo.flags & FLAG_GPSFIXOK) && !(beep_rythm % 5))
          beep(100);
        else if (GPSInfo.satnum < staticParams.GPSMininumSatellites
            && !(beep_rythm % 5))
          beep(10);
      }
    }
    // set current data as processed to avoid further calculations on the same gps data
    GPSInfo.status = PROCESSED;
    break;
  } // eof GPSInfo.status
}