Self balancing robot from Magicbit

#include <PID_v1.h>
#include "I2Cdev.h"
#include "MPU6050_6Axis_MotionApps20.h"

#if I2CDEV_IMPLEMENTATION == I2CDEV_ARDUINO_WIRE
    #include "Wire.h"
#endif



MPU6050 mpu;


bool dmpReady = false;  // set true if DMP init was successful
uint8_t mpuIntStatus;   // holds actual interrupt status byte from MPU
uint8_t devStatus;      // return status after each device operation (0 = success, !0 = error)
uint16_t packetSize;    // expected DMP packet size (default is 42 bytes)
uint16_t fifoCount;     // count of all bytes currently in FIFO
uint8_t fifoBuffer[64]; // FIFO storage buffer

Quaternion q;           // [w, x, y, z]         quaternion container
VectorFloat gravity;    // [x, y, z]            gravity vector
float ypr[3];           // [yaw, pitch, roll]   yaw/pitch/roll container and gravity vector


double originalSetpoint = 172.5;
double setpoint = originalSetpoint;
double movingAngleOffset = 0.1;
double input, output;
int moveState=0;
double Kp = 23;//set P first
double Kd = 0.8;//this value generally small
double Ki = 300;//this value should be high for better stability
PID pid(&input, &output, &setpoint, Kp, Ki, Kd, DIRECT);//pid initialize

int motL1=26;//4 pins for motor drive
int motL2=2;
int motR1=27;
int motR2=4;




volatile bool mpuInterrupt = false;     // indicates whether MPU interrupt pin has gone high
void dmpDataReady()
{
    mpuInterrupt = true;
}


void setup()
{
  ledcSetup(0, 20000, 8);//pwm setup
  ledcSetup(1, 20000, 8);
  ledcSetup(2, 20000, 8);
  ledcSetup(3, 20000, 8);
  ledcAttachPin(motL1, 0);//pinmode of motors
  ledcAttachPin(motL2, 1);
  ledcAttachPin(motR1, 2);
  ledcAttachPin(motR2, 3);
    // join I2C bus (I2Cdev library doesn't do this automatically)
  #if I2CDEV_IMPLEMENTATION == I2CDEV_ARDUINO_WIRE
  Wire.begin();
  Wire.setClock(400000); // 400kHz I2C clock. Comment this line if having compilation difficulties
#elif I2CDEV_IMPLEMENTATION == I2CDEV_BUILTIN_FASTWIRE
  Fastwire::setup(400, true);
#endif
  Serial.println(F("Initializing I2C devices..."));

  pinMode(14, INPUT);
    // initialize serial communication
    // (115200 chosen because it is required for Teapot Demo output, but it's
    // really up to you depending on your project)
    Serial.begin(9600);
    while (!Serial); // wait for Leonardo enumeration, others continue immediately

    // initialize device
    Serial.println(F("Initializing I2C devices..."));
    mpu.initialize();

    // verify connection
    Serial.println(F("Testing device connections..."));
    Serial.println(mpu.testConnection() ? F("MPU6050 connection successful") : F("MPU6050 connection failed"));

    // load and configure the DMP
    Serial.println(F("Initializing DMP..."));
    devStatus = mpu.dmpInitialize();

    // supply your own gyro offsets here, scaled for min sensitivity
    mpu.setXGyroOffset(220);
    mpu.setYGyroOffset(76);
    mpu.setZGyroOffset(-85);
    mpu.setZAccelOffset(1788); // 1688 factory default for my test chip

    // make sure it worked (returns 0 if so)
    if (devStatus == 0)
    {
        // turn on the DMP, now that it's ready
        Serial.println(F("Enabling DMP..."));
        mpu.setDMPEnabled(true);

        // enable Arduino interrupt detection
        Serial.println(F("Enabling interrupt detection (Arduino external interrupt 0)..."));
        attachInterrupt(14, dmpDataReady, RISING);
        mpuIntStatus = mpu.getIntStatus();

        // set our DMP Ready flag so the main loop() function knows it's okay to use it
        Serial.println(F("DMP ready! Waiting for first interrupt..."));
        dmpReady = true;

        // get expected DMP packet size for later comparison
        packetSize = mpu.dmpGetFIFOPacketSize();
        
        //setup PID
        
        pid.SetMode(AUTOMATIC);
        pid.SetSampleTime(10);
        pid.SetOutputLimits(-255, 255);  
    }
    else
    {
        // ERROR!
        // 1 = initial memory load failed
        // 2 = DMP configuration updates failed
        // (if it's going to break, usually the code will be 1)
        Serial.print(F("DMP Initialization failed (code "));
        Serial.print(devStatus);
        Serial.println(F(")"));
    }
}


void loop()
{
    // if programming failed, don't try to do anything
    if (!dmpReady) return;

    // wait for MPU interrupt or extra packet(s) available
    while (!mpuInterrupt && fifoCount < packetSize)
   {
        
        pid.Compute();//this time period is used to load data,so you can use this for other calculations
        motorSpeed(output);
        
    }

    // reset interrupt flag and get INT_STATUS byte
    mpuInterrupt = false;
    mpuIntStatus = mpu.getIntStatus();

    // get current FIFO count
    fifoCount = mpu.getFIFOCount();

    // check for overflow (this should never happen unless our code is too inefficient)
    if ((mpuIntStatus & 0x10) || fifoCount == 1024)
    {
        // reset so we can continue cleanly
        mpu.resetFIFO();
        Serial.println(F("FIFO overflow!"));

    // otherwise, check for DMP data ready interrupt (this should happen frequently)
    }
    else if (mpuIntStatus & 0x02)
    {
        // wait for correct available data length, should be a VERY short wait
        while (fifoCount < packetSize) fifoCount = mpu.getFIFOCount();

        // read a packet from FIFO
        mpu.getFIFOBytes(fifoBuffer, packetSize);
        
        // track FIFO count here in case there is > 1 packet available
        // (this lets us immediately read more without waiting for an interrupt)
        fifoCount -= packetSize;

        mpu.dmpGetQuaternion(&q, fifoBuffer);
        mpu.dmpGetGravity(&gravity, &q);
        mpu.dmpGetYawPitchRoll(ypr, &q, &gravity);
        #if LOG_INPUT
            Serial.print("ypr\t");
            Serial.print(ypr[0] * 180/M_PI);//euler angles
            Serial.print("\t");
            Serial.print(ypr[1] * 180/M_PI);
            Serial.print("\t");
            Serial.println(ypr[2] * 180/M_PI);
        #endif
        input = ypr[1] * 180/M_PI + 180;
   }
}
void motorSpeed(int PWM){
  
float L1,L2,R1,R2;

if(PWM>=0){//forward direction
 
  L2=0;
  L1=abs(PWM);
  R2=0;
  R1=abs(PWM);
  if(L1>=255){
    L1=R1=255;
  }
}
else {//backward direction
  L1=0;
   L2=abs(PWM);
   R1=0;
  R2=abs(PWM);
  if(L2>=255){
    L2=R2=255;
  }
}

//motor drive
ledcWrite(0,  L1);
ledcWrite(1,  L2);
ledcWrite(2,  R1*0.97);//0.97 is speed factor,because right motor have high speed than left motor,so we reduce it until motor speeds are equal
ledcWrite(3,  R2*0.97);
}