Embedded_codes/AHRS/MPU9150_AHRS_Kalman/MPU9150_AHRS_Kalman.ino
2018-02-18 14:02:33 +05:30

288 lines
9.5 KiB
C++

#include <Wire.h>
#include "Kalman.h" // Source: https://github.com/TKJElectronics/KalmanFilter
#include <I2Cdev.h>
#define RESTRICT_PITCH // Comment out to restrict roll to ±90deg instead - please read: http://www.freescale.com/files/sensors/doc/app_note/AN3461.pdf
#define LTMDIR 7
#define RTMDIR 4
#define LTMPWM 6
#define RTMPWM 5
#define LTMINT 2
#define RTMINT 3
Kalman kalmanX, kalmanY, kalmanZ; // Create the Kalman instances
const uint8_t MPU6050 = 0x68; // If AD0 is logic low on the PCB the address is 0x68, otherwise set this to 0x69
const uint8_t AK8975 = 0x0C; // Address of magnetometer
/* IMU Data */
double accX, accY, accZ;
double gyroX, gyroY, gyroZ;
double magX, magY, magZ;
int16_t tempRaw;
double roll, pitch, yaw; // Roll and pitch are calculated using the accelerometer while yaw is calculated using the magnetometer
double gyroXangle, gyroYangle, gyroZangle; // Angle calculate using the gyro only
double compAngleX, compAngleY, compAngleZ; // Calculated angle using a complementary filter
double kalAngleX, kalAngleY, kalAngleZ; // Calculated angle using a Kalman filter
uint32_t timer;
uint8_t i2cData[14]; // Buffer for I2C data
#define MAG0MAX 603
#define MAG0MIN -578
#define MAG1MAX 542
#define MAG1MIN -701
#define MAG2MAX 547
#define MAG2MIN -556
bool lDir,rDir;
float magOffset[3] = { (MAG0MAX + MAG0MIN) / 2, (MAG1MAX + MAG1MIN) / 2, (MAG2MAX + MAG2MIN) / 2 };
double magGain[3];
void motorControl(int a, int b)
{
if(lDir)
PORTD |= _BV(RTMDIR);
else
PORTD &= ~_BV(RTMDIR);
if(rDir)
PORTD |= _BV(LTMDIR);
else
PORTD &= ~_BV(LTMDIR);
analogWrite(RTMPWM,( ( abs( a ) <= 100 ) ? a + 25: 0 ));
analogWrite(LTMPWM,( ( abs( a ) <= 100 ) ? a + 25: 0 ));
}
void setup() {
delay(100); // Wait for sensors to get ready
pinMode(LTMINT, INPUT);
pinMode(RTMINT, INPUT);
pinMode(LTMDIR, OUTPUT);
pinMode(RTMDIR, OUTPUT);
pinMode(LTMPWM, OUTPUT);
pinMode(RTMPWM, OUTPUT);
Serial.begin(57600); delay(100);
Wire.begin();Serial.println('h');
TWBR = ((F_CPU / 400000L) - 16) / 2; // Set I2C frequency to 400kHz
I2Cdev::writeBits(MPU6050, 0x68, 2, 3, 0x01);
I2Cdev::writeBit(MPU6050, 0x6B, 6, 0);
I2Cdev::writeBit(MPU6050, 0x6A, 5, 0);
I2Cdev::writeBit(MPU6050, 0x37, 1, 1);
i2cData[0] = 7; // Set the sample rate to 1000Hz - 8kHz/(7+1) = 1000Hz
i2cData[1] = 0x00; // Disable FSYNC and set 260 Hz Acc filtering, 256 Hz Gyro filtering, 8 KHz sampling
i2cData[2] = 0x00; // Set Gyro Full Scale Range to ±250deg/s
i2cData[3] = 0x00; // Set Accelerometer Full Scale Range to ±2g
I2Cdev::writeBytes(MPU6050, 0x19, 4, i2cData); // Write to all four registers at once
I2Cdev::writeByte(MPU6050, 0x6B, 0x01);// PLL with X axis gyroscope reference and disable sleep mode
I2Cdev::readByte(MPU6050, 0x75, i2cData,1000);
if (i2cData[0] != 0x68) { // Read "WHO_AM_I" register
Serial.print(F("Error reading sensor"));
while (1);
}
// calibrateMag();
delay(100); // Wait for sensors to stabilize
/* Set Kalman and gyro starting angle */
updateMPU6050();
updateAK8975();
updatePitchRoll();
updateYaw();
kalmanX.setAngle(roll); // First set roll starting angle
gyroXangle = roll;
compAngleX = roll;
kalmanY.setAngle(pitch); // Then pitch
gyroYangle = pitch;
compAngleY = pitch;
kalmanZ.setAngle(yaw); // And finally yaw
gyroZangle = yaw;
compAngleZ = yaw;
timer = micros(); // Initialize the timer
}
float KP = 0,KI = 0, KD = 0;float cerr = 0;float perr = 0;
float setPitch = 0;
void control(){
float err = setPitch - kalAngleY;
cerr+=err;
cerr=(cerr>10?10:cerr);
float out = KP * (err) + KI*cerr + KD * (perr - err);
if(out<0)rDir=lDir=1;
else rDir=lDir=0;
motorControl(out,out);
}
void loop() {
/* Update all the IMU values */
updateMPU6050();
updateAK8975();
if(Serial.available()>2){
switch (Serial.read())
{
case 'p':KP = Serial.parseFloat();break;
case 'i':KI = Serial.parseFloat();break;
case 'd':KD = Serial.parseFloat();break;
case 's':setPitch = Serial.parseFloat();break;
//case 'b':kcgi = Serial.parseFloat();break;
//case 'c':kcgd = Serial.parseFloat();break;*/
//case 's':initAOffset = Serial.parseFloat();break;
//case 'e':mov = Serial.parseInt();break;
//case 't':angs = Serial.parseFloat();break;
//case 'a':an=Serial.parseFloat();break;
//case 'm':m = Serial.parseFloat();break;
}
Serial.read();
}
double dt = (double)(micros() - timer) / 1000000; // Calculate delta time
timer = micros();
/* Roll and pitch estimation */
updatePitchRoll();
double gyroXrate = gyroX / 131.0; // Convert to deg/s
double gyroYrate = gyroY / 131.0; // Convert to deg/s
#ifdef RESTRICT_PITCH
// This fixes the transition problem when the accelerometer angle jumps between -180 and 180 degrees
if ((roll < -90 && kalAngleX > 90) || (roll > 90 && kalAngleX < -90)) {
kalmanX.setAngle(roll);
compAngleX = roll;
kalAngleX = roll;
gyroXangle = roll;
} else
kalAngleX = kalmanX.getAngle(roll, gyroXrate, dt); // Calculate the angle using a Kalman filter
if (abs(kalAngleX) > 90)
gyroYrate = -gyroYrate; // Invert rate, so it fits the restricted accelerometer reading
kalAngleY = kalmanY.getAngle(pitch, gyroYrate, dt);
#else
// This fixes the transition problem when the accelerometer angle jumps between -180 and 180 degrees
if ((pitch < -90 && kalAngleY > 90) || (pitch > 90 && kalAngleY < -90)) {
kalmanY.setAngle(pitch);
compAngleY = pitch;
kalAngleY = pitch;
gyroYangle = pitch;
} else
kalAngleY = kalmanY.getAngle(pitch, gyroYrate, dt); // Calculate the angle using a Kalman filter
if (abs(kalAngleY) > 90)
gyroXrate = -gyroXrate; // Invert rate, so it fits the restricted accelerometer reading
kalAngleX = kalmanX.getAngle(roll, gyroXrate, dt); // Calculate the angle using a Kalman filter
#endif
/* Yaw estimation */
updateYaw();
double gyroZrate = gyroZ / 131.0; // Convert to deg/s
// This fixes the transition problem when the yaw angle jumps between -180 and 180 degrees
if ((yaw < -90 && kalAngleZ > 90) || (yaw > 90 && kalAngleZ < -90)) {
kalmanZ.setAngle(yaw);
compAngleZ = yaw;
kalAngleZ = yaw;
gyroZangle = yaw;
} else
kalAngleZ = kalmanZ.getAngle(yaw, gyroZrate, dt); // Calculate the angle using a Kalman filter
/* Estimate angles using gyro only */
gyroXangle += gyroXrate * dt; // Calculate gyro angle without any filter
gyroYangle += gyroYrate * dt;
gyroZangle += gyroZrate * dt;
//gyroXangle += kalmanX.getRate() * dt; // Calculate gyro angle using the unbiased rate from the Kalman filter
//gyroYangle += kalmanY.getRate() * dt;
//gyroZangle += kalmanZ.getRate() * dt;
/* Estimate angles using complimentary filter */
compAngleX = 0.93 * (compAngleX + gyroXrate * dt) + 0.07 * roll; // Calculate the angle using a Complimentary filter
compAngleY = 0.93 * (compAngleY + gyroYrate * dt) + 0.07 * pitch;
compAngleZ = 0.93 * (compAngleZ + gyroZrate * dt) + 0.07 * yaw;
// Reset the gyro angles when they has drifted too much
if (gyroXangle < -180 || gyroXangle > 180)
gyroXangle = kalAngleX;
if (gyroYangle < -180 || gyroYangle > 180)
gyroYangle = kalAngleY;
if (gyroZangle < -180 || gyroZangle > 180)
gyroZangle = kalAngleZ;
control();
/* Print Data */
#if 1
Serial.print(roll); Serial.print("\t");
Serial.print(gyroXangle); Serial.print("\t");
Serial.print(compAngleX); Serial.print("\t");
Serial.print(kalAngleX); Serial.print("\t");
Serial.print("\t");
Serial.print(pitch); Serial.print("\t");
Serial.print(gyroYangle); Serial.print("\t");
Serial.print(compAngleY); Serial.print("\t");
Serial.print(kalAngleY); Serial.print("\t");
Serial.print("\t");
Serial.print(yaw); Serial.print("\t");
Serial.print(gyroZangle); Serial.print("\t");
Serial.print(compAngleZ); Serial.print("\t");
Serial.print(kalAngleZ); Serial.print("\t");
#endif
Serial.println();
delay(10);
}
void updateMPU6050() {
I2Cdev::readBytes(MPU6050, 0x3B, 14, i2cData); // Get accelerometer and gyroscope values
accX = ((i2cData[0] << 8) | i2cData[1]);
accY = ((i2cData[2] << 8) | i2cData[3]);
accZ = ((i2cData[4] << 8) | i2cData[5]);
tempRaw = (i2cData[6] << 8) | i2cData[7];
gyroX = (i2cData[8] << 8) | i2cData[9];
gyroY = (i2cData[10] << 8) | i2cData[11];
gyroZ = (i2cData[12] << 8) | i2cData[13];
}
void updateAK8975() {
I2Cdev::writeByte(AK8975, 0x0A, 0x1);
delay(10);
I2Cdev::readBytes(AK8975, 0x03, 6, i2cData);
magY = ((i2cData[1] << 8) | i2cData[0]);
magX = ((i2cData[3] << 8) | i2cData[2]);
magZ = ((i2cData[5] << 8) | i2cData[4]);
}
void updatePitchRoll() {
#ifdef RESTRICT_PITCH // Eq. 25 and 26
roll = atan2(accY, accZ) * RAD_TO_DEG;
pitch = atan(-accX / sqrt(accY * accY + accZ * accZ)) * RAD_TO_DEG;
#else // Eq. 28 and 29
roll = atan(accY / sqrt(accX * accX + accZ * accZ)) * RAD_TO_DEG;
pitch = atan2(accX, accZ) * RAD_TO_DEG;
#endif
}
void updateYaw() { // See: http://www.freescale.com/files/sensors/doc/app_note/AN4248.pdf
/* magX *= -1; // Invert axis - this it done here, as it should be done after the calibration
magZ *= -1;
*/
double rollAngle = kalAngleX * DEG_TO_RAD;
double pitchAngle = kalAngleY * DEG_TO_RAD;
double Bfy = magZ * sin(rollAngle) - magY * cos(rollAngle);
double Bfx = magX * cos(pitchAngle) + magY * sin(pitchAngle) * sin(rollAngle) + magZ * sin(pitchAngle) * cos(rollAngle);
yaw = atan2(-Bfy, Bfx) * RAD_TO_DEG;
//yaw *= -1;
}