#include <Arduino.h>
#include <Servo.h>
#include <MPU6050_tockn.h>

MPU6050 mpu6050(Wire);

Servo servo_y; 
Servo servo_z;

/**
 * @pin_y: 对应纵向旋转舵机
 * @pin_x: 对应横向旋转舵机
 */
uint8_t pin_y =  9;
uint8_t pin_z = 11;

float angleY,angleZ,gyroz;

double P[2][2] = {{ 1, 0 },{ 0, 1 }};
double Pdot[4] ={ 0,0,0,0};
static const double Q_angle=0.001, Q_gyro=0.003, R_angle=0.5,dtt=0.005,C_0 = 1;
double q_bias, angle_err, PCt_0, PCt_1, E, K_0, K_1, t_0, t_1;

/** 
 * Kalman_Filter  卡尔曼滤波 
 * @angle_m: 角度
 * @gyro_m: 角速度
**/
void Kalman_Filter(double angle_m,double gyro_m)
{
    angleZ+=(gyro_m-q_bias) * dtt;
    Pdot[0]=Q_angle - P[0][1] - P[1][0];
    Pdot[1]=- P[1][1];
    Pdot[2]=- P[1][1];
    Pdot[3]=Q_gyro;
    P[0][0] += Pdot[0] * dtt;
    P[0][1] += Pdot[1] * dtt;
    P[1][0] += Pdot[2] * dtt;
    P[1][1] += Pdot[3] * dtt;
    angle_err = angle_m - angleZ;
    PCt_0 = C_0 * P[0][0];
    PCt_1 = C_0 * P[1][0];
    E = R_angle + C_0 * PCt_0;
    K_0 = PCt_0 / E;
    K_1 = PCt_1 / E;
    t_0 = PCt_0;
    t_1 = C_0 * P[0][1];
    P[0][0] -= K_0 * t_0;
    P[0][1] -= K_0 * t_1;
    P[1][0] -= K_1 * t_0;
    P[1][1] -= K_1 * t_1;
    angleZ+= K_0 * angle_err;
    q_bias += K_1 * angle_err;
}

void setup() {
    servo_y.attach(pin_y, 0, 180);
    servo_z.attach(pin_z , 0, 180);
    Serial.begin(9600);
    Wire.begin();
    mpu6050.begin();
    //mpu6050 自校验
    mpu6050.calcGyroOffsets(true);
}

void loop() {
  mpu6050.update();
  angleY = mpu6050.getAngleY();
  angleZ = mpu6050.getAngleZ();
  gyroz = mpu6050.getGyroZ();
  Kalman_Filter(angleZ,gyroz);
  int pos_y = int(angleY) + 90;
  int pos_z = int(angleZ) ;
  Serial.print("angleY:"); Serial.print(angleY);
  Serial.print("\tangleZ:"); Serial.print(angleZ);
  Serial.print("\tpos_x:"); Serial.print(pos_y);
  Serial.print("\tpos_z:"); Serial.println(pos_z);
  servo_y.write(pos_y);
  servo_z.write(pos_z);
 // delay(10);
}