WebSVN - FlightCtrl - /branches/V0.68d Code Redesign killagreg/GPS.c

#include <inttypes.h>
#include <stdlib.h>
#include "fc.h"
#include "ubx.h"
#include "mymath.h"
#include "timer0.h"
#include "uart.h"

#define TSK_IDLE 0
#define TSK_HOLD 1
#define TSK_HOME 2

#define GPS_STICK_SENSE 20 // must be at least in a range where 90% of the trimming does not switch of the GPS function
#define GPS_STICK_LIMIT 45 // limit of gps stick control to avoid critical flight attitudes
#define GPS_D_LIMIT_DIST 500 // for position deviations grater than 500 cm (20m) the D-Part of the PD-Controller is limited
#define GPS_D_LIMIT 50 // PD-Controntroller D-Limit.

int16_t GPS_Pitch = 0;
int16_t GPS_Roll = 0;

int32_t GPS_P_Factor = 0, GPS_D_Factor = 0;
int32_t GPSPosDev_North = 0, GPSPosDev_East = 0;

typedef struct
{
int32_t Northing;
int32_t Easting;
uint8_t Status;

} GPS_Pos_t;

// GPS coordinates for hold position
GPS_Pos_t HoldPosition = {0,0, INVALID};
// GPS coordinates for home position
GPS_Pos_t HomePosition = {0,0, INVALID};

// ---------------------------------------------------------------------------------

// set home position to current hold positon
void GPS_SetHomePosition(void)
{
HomePosition.Northing = HoldPosition.Northing;
HomePosition.Easting = HoldPosition.Easting;
HomePosition.Status = HoldPosition.Status;
if(HomePosition.Status == VALID) BeepTime = 1000; // signal if new home position was set
}

// clear home position
void GPS_ClearHomePosition(void)
{
HomePosition.Status = INVALID;
}

// disable GPS control sticks
void GPS_Neutral(void)
{
GPS_Pitch = 0;
GPS_Roll = 0;
}

// calculates the GPS control sticks values from the deviation to target position
void GPS_PDController(GPS_Pos_t *TargetPos)
{
int32_t coscompass, sincompass;
int32_t P_North = 0, D_North = 0, P_East = 0, D_East = 0;
int32_t PD_North = 0, PD_East = 0;

if( (TargetPos->Status == VALID) && (GPSInfo.status == VALID) && (GPSInfo.satfix == SATFIX_3D))
{
GPSPosDev_North = GPSInfo.utmnorth - TargetPos->Northing;
GPSPosDev_East = GPSInfo.utmeast - TargetPos->Easting;

DebugOut.Analog[12] = GPSPosDev_North;
DebugOut.Analog[13] = GPSPosDev_East;

//DebugOut.Analog[12] = GPSInfo.velnorth;
//DebugOut.Analog[13] = GPSInfo.veleast;

//Calculate PD-components of the controller (negative sign for compensation)
P_North = -(GPS_P_Factor * GPSPosDev_North)/2048;
D_North = -(GPS_D_Factor * GPSInfo.velnorth)/512;
P_East = -(GPS_P_Factor * GPSPosDev_East)/2048;
D_East = -(GPS_D_Factor * GPSInfo.veleast)/512;

if( (abs(GPSPosDev_North) > GPS_D_LIMIT_DIST) || (abs(GPSPosDev_East) > GPS_D_LIMIT_DIST) )
{
if (D_North > GPS_D_LIMIT) D_North = GPS_D_LIMIT;
else if (D_North < -GPS_D_LIMIT) D_North = -GPS_D_LIMIT;
if (D_East > GPS_D_LIMIT) D_East = GPS_D_LIMIT;
else if (D_East < -GPS_D_LIMIT) D_East = -GPS_D_LIMIT;
}

// PD-controller
PD_North = P_North + D_North;
PD_East = P_East + D_East;

// GPS to pitch and roll settings

//A positive pitch 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 pitch 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 pitch).
// 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 GPS_Pitch and GPS_Roll variable is contrarily to the stick values
// in the fc.c. Therefore a positive north deviation/velocity should result in a positive
// GPS_Pitch and a positive east deviation/velocity should result in a negative GPS_Roll.

// rotation transformation to compass heading to match any copter orientation
if (CompassHeading < 0) // no valid compass data
{ // disable GPS
GPS_Neutral();
}
else
{
coscompass = (int32_t)c_cos_8192(CompassHeading);
sincompass = (int32_t)c_sin_8192(CompassHeading);
GPS_Roll = (int16_t)((coscompass * PD_East - sincompass * PD_North) / 8192);
GPS_Pitch = -1*(int16_t)((sincompass * PD_East + coscompass * PD_North) / 8192);
}
// limit GPS controls
if (GPS_Pitch > GPS_STICK_LIMIT) GPS_Pitch = GPS_STICK_LIMIT;
else if (GPS_Pitch < -GPS_STICK_LIMIT) GPS_Pitch = -GPS_STICK_LIMIT;
if (GPS_Roll > GPS_STICK_LIMIT) GPS_Roll = GPS_STICK_LIMIT;
else if (GPS_Roll < -GPS_STICK_LIMIT) GPS_Roll = -GPS_STICK_LIMIT;
}
else // invalid input data
{
BeepTime = 50;
GPS_Neutral();
}
}

void GPS_Main(uint8_t ctrl)
{
static uint8_t GPS_Task = TSK_IDLE;
int16_t satbeep;

// ctrl enables the gps feature
if(ctrl < 70) GPS_Task = TSK_IDLE;
else if (ctrl < 160) GPS_Task = TSK_HOLD;
else GPS_Task = TSK_HOME; // ctrl >= 160

switch(GPSInfo.status)
{
case INVALID: // invalid gps data
GPS_Neutral();
if(GPS_Task != TSK_IDLE)
{
BeepTime = 100; // beep if signal is neccesary
}
break;
case PROCESSED: // if gps data are already processed
// 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 VALID: // new valid data from gps device
// if the gps data quality is sufficient
if (GPSInfo.satfix == SATFIX_3D)
{
switch(GPS_Task) // check what's to do
{
case TSK_IDLE:
// update hold point to current gps position
HoldPosition.Northing = GPSInfo.utmnorth;
HoldPosition.Easting = GPSInfo.utmeast;
HoldPosition.Status = VALID;
// disable gps control
GPS_Neutral();
break; // eof TSK_IDLE
case TSK_HOLD:
if(HoldPosition.Status == VALID)
{
// if sticks are centered (no manual control)
if ((MaxStickPitch < GPS_STICK_SENSE) && (MaxStickRoll < GPS_STICK_SENSE))
{
GPS_PDController(&HoldPosition);
}
else // MK controlled by user
{
// update hold point to current gps position
HoldPosition.Northing = GPSInfo.utmnorth;
HoldPosition.Easting = GPSInfo.utmeast;
HoldPosition.Status = GPSInfo.status;
// disable gps control
GPS_Neutral();
}
}
break; // eof TSK_HOLD
case TSK_HOME:
if(HomePosition.Status == VALID)
{
// update hold point to current gps position
// to avoid a flight back if home comming is deactivated
HoldPosition.Northing = GPSInfo.utmnorth;
HoldPosition.Easting = GPSInfo.utmeast;
HoldPosition.Status = GPSInfo.status;
// if sticks are centered (no manual control)
if((MaxStickPitch < GPS_STICK_SENSE) && (MaxStickRoll < GPS_STICK_SENSE))
{
GPS_PDController(&HomePosition);
}
else // manual control
{
GPS_Neutral();
}
}
else // bad home position
{
BeepTime = 50; // signal invalid home position
// try to hold at least the position as a fallback option
// if sticks are centered (no manual control)
if((MaxStickPitch < GPS_STICK_SENSE) && (MaxStickRoll < GPS_STICK_SENSE) && (HoldPosition.Status == VALID))
{
GPS_PDController(&HoldPosition);
}
else // manual control or no rteference position
{
GPS_Neutral();
}
}
break; // eof TSK_HOME
default: // unhandled task
GPS_Neutral();
break; // eof default
} // eof switch GPS_Task
} // eof 3D-FIX

else // no 3D-SATFIX
{ // disable gps control
GPS_Neutral();
if(GPS_Task != TSK_IDLE)
{
satbeep = 1800 - (int16_t)GPSInfo.satnum * 225; // is zero at 8 sats
if (satbeep < 0) satbeep = 0;
BeepTime = 50 + (uint16_t)satbeep; // max 1850 * 0.1 ms =
}
}
// set current data as processed to avoid further calculations on the same gps data
GPSInfo.status = PROCESSED;
break;
} // eof GPSInfo.status
DebugOut.Analog[14] = GPS_Pitch;
DebugOut.Analog[15] = GPS_Roll;
}

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