File content as of revision 0:fe2fd7f5dac3:

#include <L3GD20.h>
#include <LSM303DLHC.h>

L3GD20 gyro(p28, p27);
Serial debug(USBTX,USBRX);
LSM303DLHC compass(p28, p27);

// Uncomment the below line to use this axis definition: 
   // X axis pointing forward
   // Y axis pointing to the right 
   // and Z axis pointing down.
// Positive pitch : nose up
// Positive roll : right wing down
// Positive yaw : clockwise
int SENSOR_SIGN[9] = {1,1,1,-1,-1,-1,1,1,1}; //Correct directions x,y,z - gyro, accelerometer, magnetometer
// Uncomment the below line to use this axis definition: 
   // X axis pointing forward
   // Y axis pointing to the left 
   // and Z axis pointing up.
// Positive pitch : nose down
// Positive roll : right wing down
// Positive yaw : counterclockwise
//int SENSOR_SIGN[9] = {1,-1,-1,-1,1,1,1,-1,-1}; //Correct directions x,y,z - gyro, accelerometer, magnetometer

// tested with Arduino Uno with ATmega328 and Arduino Duemilanove with ATMega168

// LSM303 accelerometer: 8 g sensitivity
// 3.8 mg/digit; 1 g = 256
#define GRAVITY 256  //this equivalent to 1G in the raw data coming from the accelerometer 

#define ToRad(x) ((x)*0.01745329252)  // *pi/180
#define ToDeg(x) ((x)*57.2957795131)  // *180/pi

// L3G4200D gyro: 2000 dps full scale
// 70 mdps/digit; 1 dps = 0.07
#define Gyro_Gain_X 0.07 //X axis Gyro gain
#define Gyro_Gain_Y 0.07 //Y axis Gyro gain
#define Gyro_Gain_Z 0.07 //Z axis Gyro gain
#define Gyro_Scaled_X(x) ((x)*ToRad(Gyro_Gain_X)) //Return the scaled ADC raw data of the gyro in radians for second
#define Gyro_Scaled_Y(x) ((x)*ToRad(Gyro_Gain_Y)) //Return the scaled ADC raw data of the gyro in radians for second
#define Gyro_Scaled_Z(x) ((x)*ToRad(Gyro_Gain_Z)) //Return the scaled ADC raw data of the gyro in radians for second

// LSM303 magnetometer calibration constants; use the Calibrate example from
// the Pololu LSM303 library to find the right values for your board
#define M_X_MIN -580
#define M_Y_MIN -650
#define M_Z_MIN -770
#define M_X_MAX 495
#define M_Y_MAX 480
#define M_Z_MAX 370
//MIN x: -576.000000  y: -645.000000  z: -767.000000
//MAX x: 489.000000  y: 475.000000  z: 363.000000

#define Kp_ROLLPITCH 0.02
#define Ki_ROLLPITCH 0.00002
#define Kp_YAW 1.2
#define Ki_YAW 0.00002

/*For debugging purposes*/
//OUTPUTMODE=1 will print the corrected data, 
//OUTPUTMODE=0 will print uncorrected data of the gyros (with drift)
#define OUTPUTMODE 1

//#define PRINT_DCM 0     //Will print the whole direction cosine matrix
#define PRINT_ANALOGS 0 //Will print the analog raw data
#define PRINT_EULER 1   //Will print the Euler angles Roll, Pitch and Yaw

#define STATUS_LED 13 

float G_Dt=0.02;    // Integration time (DCM algorithm)  We will run the integration loop at 50Hz if possible

Timer tim;   //general purpuse timer
long timer=0;
long timer_old;
long timer24=0; //Second timer used to print values 
int AN[6]; //array that stores the gyro and accelerometer data
int AN_OFFSET[6]={0,0,0,0,0,0}; //Array that stores the Offset of the sensors

int gyro_x;
int gyro_y;
int gyro_z;
int accel_x;
int accel_y;
int accel_z;
int magnetom_x;
int magnetom_y;
int magnetom_z;
float c_magnetom_x;
float c_magnetom_y;
float c_magnetom_z;
float MAG_Heading;

float Accel_Vector[3]= {0,0,0}; //Store the acceleration in a vector
float Gyro_Vector[3]= {0,0,0};//Store the gyros turn rate in a vector
float Omega_Vector[3]= {0,0,0}; //Corrected Gyro_Vector data
float Omega_P[3]= {0,0,0};//Omega Proportional correction
float Omega_I[3]= {0,0,0};//Omega Integrator
float Omega[3]= {0,0,0};

// Euler angles
float roll;
float pitch;
float yaw;

float errorRollPitch[3]= {0,0,0}; 
float errorYaw[3]= {0,0,0};

unsigned int counter=0;
int gyro_sat=0;

float DCM_Matrix[3][3]= {
  {
    1,0,0  }
  ,{
    0,1,0  }
  ,{
    0,0,1  }
}; 
float Update_Matrix[3][3]={{0,1,2},{3,4,5},{6,7,8}}; //Gyros here


float Temporary_Matrix[3][3]={
  {
    0,0,0  }
  ,{
    0,0,0  }
  ,{
    0,0,0  }
};

float min(float x, float y)
{
    if(x < y)
    {return x;}
    else 
    {return y;}
}
float max(float x, float y)
{
    if(x > y)
    {return x;}
    else 
    {return y;}
}

void Compass_Heading()
{
  float MAG_X;
  float MAG_Y;
  float cos_roll;
  float sin_roll;
  float cos_pitch;
  float sin_pitch;
  
  cos_roll = cos(roll);
  sin_roll = sin(roll);
  cos_pitch = cos(pitch);
  sin_pitch = sin(pitch);
  
  // adjust for LSM303 compass axis offsets/sensitivity differences by scaling to +/-0.5 range
  c_magnetom_x = (float)(magnetom_x - SENSOR_SIGN[6]*M_X_MIN) / (M_X_MAX - M_X_MIN) - SENSOR_SIGN[6]*0.5;
  c_magnetom_y = (float)(magnetom_y - SENSOR_SIGN[7]*M_Y_MIN) / (M_Y_MAX - M_Y_MIN) - SENSOR_SIGN[7]*0.5;
  c_magnetom_z = (float)(magnetom_z - SENSOR_SIGN[8]*M_Z_MIN) / (M_Z_MAX - M_Z_MIN) - SENSOR_SIGN[8]*0.5;
  
  // Tilt compensated Magnetic filed X:
  MAG_X = c_magnetom_x*cos_pitch+c_magnetom_y*sin_roll*sin_pitch+c_magnetom_z*cos_roll*sin_pitch;
  // Tilt compensated Magnetic filed Y:
  MAG_Y = c_magnetom_y*cos_roll-c_magnetom_z*sin_roll;
  // Magnetic Heading
  MAG_Heading = atan2(-MAG_Y,MAG_X);
}
float Vector_Dot_Product(float vector1[3],float vector2[3])
{
  float op=0;
  
  for(int c=0; c<3; c++)
  {
  op = op + (vector1[c]*vector2[c]);
  }
  
  return op; 
}
//Computes the cross product of two vectors
void Vector_Cross_Product(float vectorOut[3], float v1[3],float v2[3])
{
  vectorOut[0]= (v1[1]*v2[2]) - (v1[2]*v2[1]);
  vectorOut[1]= (v1[2]*v2[0]) - (v1[0]*v2[2]);
  vectorOut[2]= (v1[0]*v2[1]) - (v1[1]*v2[0]);
}

//Multiply the vector by a scalar. 
void Vector_Scale(float vectorOut[3],float vectorIn[3], float scale2)
{
  for(int c=0; c<3; c++)
  {
   vectorOut[c]=vectorIn[c]*scale2; 
  }
}

void Vector_Add(float vectorOut[3],float vectorIn1[3], float vectorIn2[3])
{
  for(int c=0; c<3; c++)
  {
     vectorOut[c]=vectorIn1[c]+vectorIn2[c];
  }
}
/**************************************************/
void Normalize(void)
{
  float error=0;
  float temporary[3][3];
  float renorm=0;
  
  error= -Vector_Dot_Product(&DCM_Matrix[0][0],&DCM_Matrix[1][0])*.5; //eq.19

  Vector_Scale(&temporary[0][0], &DCM_Matrix[1][0], error); //eq.19
  Vector_Scale(&temporary[1][0], &DCM_Matrix[0][0], error); //eq.19
  
  Vector_Add(&temporary[0][0], &temporary[0][0], &DCM_Matrix[0][0]);//eq.19
  Vector_Add(&temporary[1][0], &temporary[1][0], &DCM_Matrix[1][0]);//eq.19
  
  Vector_Cross_Product(&temporary[2][0],&temporary[0][0],&temporary[1][0]); // c= a x b //eq.20
  
  renorm= .5 *(3 - Vector_Dot_Product(&temporary[0][0],&temporary[0][0])); //eq.21
  Vector_Scale(&DCM_Matrix[0][0], &temporary[0][0], renorm);
  
  renorm= .5 *(3 - Vector_Dot_Product(&temporary[1][0],&temporary[1][0])); //eq.21
  Vector_Scale(&DCM_Matrix[1][0], &temporary[1][0], renorm);
  
  renorm= .5 *(3 - Vector_Dot_Product(&temporary[2][0],&temporary[2][0])); //eq.21
  Vector_Scale(&DCM_Matrix[2][0], &temporary[2][0], renorm);
}

float constrain(float x,float a, float b)
{
    if(x <a)
    {
        return a;
    }
    if(x > b)
    {
        return b;
    }
    return x;
}
/**************************************************/
void Drift_correction(void)
{
  float mag_heading_x;
  float mag_heading_y;
  float errorCourse;
  //Compensation the Roll, Pitch and Yaw drift. 
  static float Scaled_Omega_P[3];
  static float Scaled_Omega_I[3];
  float Accel_magnitude;
  float Accel_weight;
  
  
  //*****Roll and Pitch***************

  // Calculate the magnitude of the accelerometer vector
  Accel_magnitude = sqrt(Accel_Vector[0]*Accel_Vector[0] + Accel_Vector[1]*Accel_Vector[1] + Accel_Vector[2]*Accel_Vector[2]);
  Accel_magnitude = Accel_magnitude / GRAVITY; // Scale to gravity.
  // Dynamic weighting of accelerometer info (reliability filter)
  // Weight for accelerometer info (<0.5G = 0.0, 1G = 1.0 , >1.5G = 0.0)
  Accel_weight = constrain(1 - 2*abs(1 - Accel_magnitude),0,1);  //  

  Vector_Cross_Product(&errorRollPitch[0],&Accel_Vector[0],&DCM_Matrix[2][0]); //adjust the ground of reference
  Vector_Scale(&Omega_P[0],&errorRollPitch[0],Kp_ROLLPITCH*Accel_weight);
  
  Vector_Scale(&Scaled_Omega_I[0],&errorRollPitch[0],Ki_ROLLPITCH*Accel_weight);
  Vector_Add(Omega_I,Omega_I,Scaled_Omega_I);     
  
  //*****YAW***************
  // We make the gyro YAW drift correction based on compass magnetic heading
 
  mag_heading_x = cos(MAG_Heading);
  mag_heading_y = sin(MAG_Heading);
  errorCourse=(DCM_Matrix[0][0]*mag_heading_y) - (DCM_Matrix[1][0]*mag_heading_x);  //Calculating YAW error
  Vector_Scale(errorYaw,&DCM_Matrix[2][0],errorCourse); //Applys the yaw correction to the XYZ rotation of the aircraft, depeding the position.
  
  Vector_Scale(&Scaled_Omega_P[0],&errorYaw[0],Kp_YAW);//.01proportional of YAW.
  Vector_Add(Omega_P,Omega_P,Scaled_Omega_P);//Adding  Proportional.
  
  Vector_Scale(&Scaled_Omega_I[0],&errorYaw[0],Ki_YAW);//.00001Integrator
  Vector_Add(Omega_I,Omega_I,Scaled_Omega_I);//adding integrator to the Omega_I
}
/**************************************************/
/*
void Accel_adjust(void)
{
 Accel_Vector[1] += Accel_Scale(speed_3d*Omega[2]);  // Centrifugal force on Acc_y = GPS_speed*GyroZ
 Accel_Vector[2] -= Accel_Scale(speed_3d*Omega[1]);  // Centrifugal force on Acc_z = GPS_speed*GyroY 
}
*/
/**************************************************/
/**************************************************/
//Multiply two 3x3 matrixs. This function developed by Jordi can be easily adapted to multiple n*n matrix's. (Pero me da flojera!). 
void Matrix_Multiply(float a[3][3], float b[3][3],float mat[3][3])
{
  float op[3]; 
  for(int x=0; x<3; x++)
  {
    for(int y=0; y<3; y++)
    {
      for(int w=0; w<3; w++)
      {
       op[w]=a[x][w]*b[w][y];
      } 
      mat[x][y]=0;
      mat[x][y]=op[0]+op[1]+op[2];
    }
  }
}
void Matrix_update(void)
{
  Gyro_Vector[0]=Gyro_Scaled_X(gyro_x); //gyro x roll
  Gyro_Vector[1]=Gyro_Scaled_Y(gyro_y); //gyro y pitch
  Gyro_Vector[2]=Gyro_Scaled_Z(gyro_z); //gyro Z yaw
  
  Accel_Vector[0]=accel_x;
  Accel_Vector[1]=accel_y;
  Accel_Vector[2]=accel_z;
    
  Vector_Add(&Omega[0], &Gyro_Vector[0], &Omega_P[0]);  //adding proportional term
  Vector_Add(&Omega_Vector[0], &Omega[0], &Omega_I[0]); //adding Integrator term

  //Accel_adjust();    //Remove centrifugal acceleration.   We are not using this function in this version - we have no speed measurement
         
  Update_Matrix[0][0]=0;
  Update_Matrix[0][1]=-G_Dt*Omega_Vector[2];//-z
  Update_Matrix[0][2]=G_Dt*Omega_Vector[1];//y
  Update_Matrix[1][0]=G_Dt*Omega_Vector[2];//z
  Update_Matrix[1][1]=0;
  Update_Matrix[1][2]=-G_Dt*Omega_Vector[0];//-x
  Update_Matrix[2][0]=-G_Dt*Omega_Vector[1];//-y
  Update_Matrix[2][1]=G_Dt*Omega_Vector[0];//x
  Update_Matrix[2][2]=0;

  Matrix_Multiply(DCM_Matrix,Update_Matrix,Temporary_Matrix); //a*b=c

  for(int x=0; x<3; x++) //Matrix Addition (update)
  {
    for(int y=0; y<3; y++)
    {
      DCM_Matrix[x][y] = DCM_Matrix[x][y]+ Temporary_Matrix[x][y];
    } 
  }
}

void Euler_angles(void)
{
  pitch = -asin(DCM_Matrix[2][0]);
  roll = atan2(DCM_Matrix[2][1],DCM_Matrix[2][2]);
  yaw = atan2(DCM_Matrix[1][0],DCM_Matrix[0][0]);
}


void Gyro_Init()
{
  //gyro.init(); OK
  char data = 0x0F;
  gyro.write_reg(GYR_ADDRESS, L3GD20_CTRL_REG1, data); // normal power mode, all axes enabled, 100 Hz 
  data = 0x20;
  gyro.write_reg(GYR_ADDRESS, L3GD20_CTRL_REG4, data); // 2000 dps full scale
}

void Read_Gyro(float* gx, float* gy, float* gz)
{
  gyro.read(gx, gy, gz);
  AN[0] = *gx;
  AN[1] = *gy;
  AN[2] = *gz;
  gyro_x = SENSOR_SIGN[0] * (AN[0] - AN_OFFSET[0]);
  gyro_y = SENSOR_SIGN[1] * (AN[1] - AN_OFFSET[1]);
  gyro_z = SENSOR_SIGN[2] * (AN[2] - AN_OFFSET[2]);
}

void Accel_Init()
{
//  compass.init(); OK
    char data = 0x47;
    compass.write_reg(0x32, CTRL_REG1_A, data); // normal power mode, all axes enabled, 50 Hz ACC
    data = 0x28;
    compass.write_reg(0x32, CTRL_REG4_A, data); // 8 g full scale: FS = 10 on DLHC; high resolution output mode ACC
}

// Reads x,y and z accelerometer registers
void Read_Accel(float* ax, float* ay, float* az)
{
  compass.readacc(ax, ay, az);
  
  AN[3] = *ax;
  AN[4] = *ay;
  AN[5] = *az;
  accel_x = SENSOR_SIGN[3] * (AN[3] - AN_OFFSET[3]);
  accel_y = SENSOR_SIGN[4] * (AN[4] - AN_OFFSET[4]);
  accel_z = SENSOR_SIGN[5] * (AN[5] - AN_OFFSET[5]);
}

void Compass_Init()
{
  char data = 0x00;
    compass.write_reg(0x3c, CTRL_REG1_A, data); // continuous conversion mode
  // 15 Hz default
}

void Read_Compass(float* mx, float* my, float* mz)
{
  compass.readcomp(mx, my, mz);
  
  magnetom_x = SENSOR_SIGN[6] * (*mx);
  magnetom_y = SENSOR_SIGN[7] * (*my);
  magnetom_z = SENSOR_SIGN[8] * (*mz);
}

void printdata(Serial debug)
{    
      debug.printf("!");
      debug.printf("ANG:");
      debug.printf("%lf",ToDeg(roll));
      debug.printf(",");
      debug.printf("%lf",ToDeg(pitch));
      debug.printf(",");
      debug.printf("%lf",ToDeg(yaw));      
      debug.printf("\n\r");    
      
}

long convert_to_dec(float x)
{
  return x*10000000;
}
//Computes the dot product of two vectors