濾波演算法總結
阿新 • • 發佈：2019-02-08
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#include <Wire.h> // I2C library, gyroscope
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// Accelerometer ADXL345
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#define ACC (0x53) //ADXL345 ACC address
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#define A_TO_READ (6) //num of bytes we are going to read each time (two bytes for each axis)
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// Gyroscope ITG3200
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#define GYRO 0x68 // gyro address, binary = 11101000 when AD0 is connected to Vcc (see schematics of your breakout board)
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#define G_SMPLRT_DIV 0x15
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#define G_DLPF_FS 0x16
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#define G_INT_CFG 0x17
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#define G_PWR_MGM 0x3E
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#define G_TO_READ 8 // 2 bytes for each axis x, y, z
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// offsets are chip specific.
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int a_offx = 0;
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int a_offy = 0;
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int a_offz = 0;
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int g_offx = 0;
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int g_offy = 0;
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int g_offz = 0;
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////////////////////////
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////////////////////////
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char str[512];
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void initAcc() {
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//Turning on the ADXL345
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writeTo(ACC, 0x2D, 0);
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writeTo(ACC, 0x2D, 16);
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writeTo(ACC, 0x2D, 8);
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//by default the device is in +-2g range reading
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}
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void getAccelerometerData(int* result) {
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int regAddress = 0x32; //first axis-acceleration-data register on the ADXL345
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byte buff[A_TO_READ];
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readFrom(ACC, regAddress, A_TO_READ, buff); //read the acceleration data from the ADXL345
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//each axis reading comes in 10 bit resolution, ie 2 bytes. Least Significat Byte first!!
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//thus we are converting both bytes in to one int
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result[0] = (((int)buff[1]) << 8) | buff[0] + a_offx;
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result[1] = (((int)buff[3]) << 8) | buff[2] + a_offy;
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result[2] = (((int)buff[5]) << 8) | buff[4] + a_offz;
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}
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//initializes the gyroscope
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void initGyro()
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{
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/*****************************************
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* ITG 3200
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* power management set to:
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* clock select = internal oscillator
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* no reset, no sleep mode
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* no standby mode
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* sample rate to = 125Hz
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* parameter to +/- 2000 degrees/sec
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* low pass filter = 5Hz
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* no interrupt
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******************************************/
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writeTo(GYRO, G_PWR_MGM, 0x00);
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writeTo(GYRO, G_SMPLRT_DIV, 0x07); // EB, 50, 80, 7F, DE, 23, 20, FF
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writeTo(GYRO, G_DLPF_FS, 0x1E); // +/- 2000 dgrs/sec, 1KHz, 1E, 19
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writeTo(GYRO, G_INT_CFG, 0x00);
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}
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void getGyroscopeData(int * result)
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{
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/**************************************
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Gyro ITG-3200 I2C
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registers:
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temp MSB = 1B, temp LSB = 1C
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x axis MSB = 1D, x axis LSB = 1E
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y axis MSB = 1F, y axis LSB = 20
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z axis MSB = 21, z axis LSB = 22
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*************************************/
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int regAddress = 0x1B;
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int temp, x, y, z;
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byte buff[G_TO_READ];
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readFrom(GYRO, regAddress, G_TO_READ, buff); //read the gyro data from the ITG3200
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result[0] = ((buff[2] << 8) | buff[3]) + g_offx;
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result[1] = ((buff[4] << 8) | buff[5]) + g_offy;
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result[2] = ((buff[6] << 8) | buff[7]) + g_offz;
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result[3] = (buff[0] << 8) | buff[1]; // temperature
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}
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float xz=0,yx=0,yz=0;
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float p_xz=1,p_yx=1,p_yz=1;
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float q_xz=0.0025,q_yx=0.0025,q_yz=0.0025;
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float k_xz=0,k_yx=0,k_yz=0;
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float r_xz=0.25,r_yx=0.25,r_yz=0.25;
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//int acc_temp[3];
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//float acc[3];
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int acc[3];
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int gyro[4];
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float Axz;
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float Ayx;
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float Ayz;
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float t=0.025;
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void setup()
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{
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Serial.begin(9600);
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Wire.begin();
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initAcc();
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initGyro();
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}
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//unsigned long timer = 0;
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//float o;
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void loop()
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{
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getAccelerometerData(acc);
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getGyroscopeData(gyro);
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//timer = millis();
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sprintf(str, "%d,%d,%d,%d,%d,%d", acc[0],acc[1],acc[2],gyro[0],gyro[1],gyro[2]);
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//acc[0]=acc[0];
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//acc[2]=acc[2];
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//acc[1]=acc[1];
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//r=sqrt(acc[0]*acc[0]+acc[1]*acc[1]+acc[2]*acc[2]);
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gyro[0]=gyro[0]/ 14.375;
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gyro[1]=gyro[1]/ (-14.375);
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gyro[2]=gyro[2]/ 14.375;
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Axz=(atan2(acc[0],acc[2]))*180/PI;
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Ayx=(atan2(acc[0],acc[1]))*180/PI;
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/*if((acc[0]!=0)&&(acc[1]!=0))
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{
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Ayx=(atan2(acc[0],acc[1]))*180/PI;
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}
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else
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{
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Ayx=t*gyro[2];
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}*/
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Ayz=(atan2(acc[1],acc[2]))*180/PI;
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//kalman filter
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calculate_xz();
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calculate_yx();
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calculate_yz();
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//sprintf(str, "%d,%d,%d", xz_1, xy_1, x_1);
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//Serial.print(xz);Serial.print(",");
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//Serial.print(yx);Serial.print(",");
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//Serial.print(yz);Serial.print(",");
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//sprintf(str, "%d,%d,%d,%d,%d,%d", acc[0],acc[1],acc[2],gyro[0],gyro[1],gyro[2]);
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//sprintf(str, "%d,%d,%d",gyro[0],gyro[1],gyro[2]);
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Serial.print(Axz);Serial.print(",");
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//Serial.print(Ayx);Serial.print(",");
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//Serial.print(Ayz);Serial.print(",");
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//Serial.print(str);
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//o=gyro[2];//w=acc[2];
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//Serial.print(o);Serial.print(",");
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//Serial.print(w);Serial.print(",");
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Serial.print("\n");
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//delay(50);
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}
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void calculate_xz()
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{
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xz=xz+t*gyro[1];
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p_xz=p_xz+q_xz;
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k_xz=p_xz/(p_xz+r_xz);
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xz=xz+k_xz*(Axz-xz);
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p_xz=(1-k_xz)*p_xz;
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}
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void calculate_yx()
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{
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yx=yx+t*gyro[2];
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p_yx=p_yx+q_yx;
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k_yx=p_yx/(p_yx+r_yx);
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yx=yx+k_yx*(Ayx-yx);
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p_yx=(1-k_yx)*p_yx;
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}
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void calculate_yz()
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{
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yz=yz+t*gyro[0];
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p_yz=p_yz+q_yz;
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k_yz=p_yz/(p_yz+r_yz);
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yz=yz+k_yz*(Ayz-yz);
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p_yz=(1-k_yz)*p_yz;
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}
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//---------------- Functions
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//Writes val to address register on ACC
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void writeTo(int DEVICE, byte address, byte val) {
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Wire.beginTransmission(DEVICE); //start transmission to ACC
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Wire.write(address); // send register address
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Wire.write(val); // send value to write
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Wire.endTransmission(); //end transmission
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}
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//reads num bytes starting from address register on ACC in to buff array
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void readFrom(int DEVICE, byte address, int num, byte buff[]) {
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Wire.beginTransmission(DEVICE); //start transmission to ACC
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Wire.write(address); //sends address to read from
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Wire.endTransmission(); //end transmission
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Wire.beginTransmission(DEVICE); //start transmission to ACC
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Wire.requestFrom(DEVICE, num); // request 6 bytes from ACC
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int i = 0;
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while(Wire.available()) //ACC may send less than requested (abnormal)
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{
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buff[i] = Wire.read(); // receive a byte
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i++;
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}
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Wire.endTransmission(); //end transmission
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