Why is my line-following robot spinning around?

Projects General Guidance
1

I have a map and my robot is moving on this map using the PID algorithm. Since I need manual intervention in some turns, I run the system by creating various scenario functions (30 of them). When I start the system from the beginning, my robot starts to turn around after about 20 scenarios. When I start from the middle, it finishes successfully. Apart from this, I tried all the parts with various scenarios. I tried all the scenarios by moving away from the start line and this problem started to occur one scenario ahead each time. What could be the cause of this?

#include <QTRSensors.h>

#define Rpwm1 6
#define RDir1 7
#define RDir2 8
#define Lpwm1 11
#define LDir1 10
#define LDir2 9

#define Buzzer 3



QTRSensors qtr;

const uint8_t SensorCount = 8;
uint16_t sensorValues[SensorCount];

float LeftBaseSpeed  = 60 ;
float RightBaseSpeed = 60 ;
float TurnTime=100; //milisaniye
float TurnSpeed=80;
float StraightSpeed=70;
float StraightTime=70;
float CheckTime=300;

float Kp = 0.0275;//0.0275;//0.07
float Kd =0.15 ;//0.3 ;//0.275;// 0.1   ; // 2
float Ki =0.0001; //0.0001;// 0.0001 ; //0.0001

int FinalError = 0;
int Error = 0;
int ExtraSpeed = 0;
int RightSpeed = 0;
int LeftSpeed = 0;
int Integral = 0;
int Val = 0;
int donus=22;
int senaryo=22;
int baslangicZamani=0;
unsigned int Position = 3500;

byte WhiteLine = 0;



void setup()
{
  // configure the sensors
  qtr.setTypeAnalog();
  qtr.setSensorPins((const uint8_t[]){A0, A1, A2, A3, A4, A5,A6,A7}, SensorCount);
  qtr.setEmitterPin(2);

  pinMode(Rpwm1, OUTPUT);
  pinMode(Lpwm1, OUTPUT);
  pinMode(RDir1, OUTPUT);
  pinMode(RDir2, OUTPUT);
  pinMode(LDir1, OUTPUT);
  pinMode(LDir2, OUTPUT);
  pinMode(Buzzer, OUTPUT);
//  pinMode(LED1, OUTPUT);
//  pinMode(LED2, OUTPUT);
//  pinMode(MZ80, INPUT_PULLUP);
//  pinMode(startbuton, INPUT_PULLUP);
  
  delay(500);
  pinMode(LED_BUILTIN, OUTPUT);
  digitalWrite(LED_BUILTIN, HIGH); // turn on Arduino's LED to indicate we are in calibration mode
 //  Serial.begin(9600);
  for (uint16_t i = 0; i < 200; i++)
  {
    qtr.calibrate();
  }
  digitalWrite(LED_BUILTIN, LOW);
  Blink();// turn off Arduino's LED to indicate we are through with calibration
  
  delay(1000);
}

void loop()
{
  
      switch(senaryo)
      {
           case 0:Senaryo0();break;
           case 1:Senaryo1();break;
           case 2:Senaryo2();break;
           case 3:Senaryo3();break;
           case 4:Senaryo4();break;
           case 5:Senaryo5();break;
           case 6:Senaryo6();break;
           case 7:Senaryo7();break;
           case 8:Senaryo8();break;
           case 9:Senaryo9();break;
            case 10:Senaryo10();break;
             case 11:Senaryo11();break;
             case 12:Senaryo12();break;
              case 13:Senaryo13();break;
              case 14:Senaryo14();break;
              case 15:Senaryo15();break;
              case 16:Senaryo16();break;
              case 17:Senaryo17();break;
              case 18:Senaryo18();break;
              case 19:Senaryo19();break;
              case 20:Senaryo20();break;
              case 21:Senaryo21();break;
              case 22:Senaryo22();break;
              case 23:Senaryo23();break;
              case 24:Senaryo24();break;
              case 25:Senaryo25();break;
              case 26:Senaryo26();break;
              case 27:Senaryo27();break;
              case 28:Senaryo28();break;
              case 29:Senaryo29();break;
              case 30:Senaryo30();break;
              case 31:Senaryo31();break;
              case 32:Senaryo32();break;
             
             
           
          default:MotorsSpeed(0,0);break;
        
      }
  

   // WriteSensorValues();

}


void Senaryo0()
{
  ReadLine();
  CheckStraight();
  if(donus==1)
  {
    senaryo=1;
  }
}

void Senaryo1()
{
  ReadLine();
  CheckRightTurn(CheckTime);
  if(donus==2)
  {
    senaryo=2;
  }
}

void Senaryo2()
{
   
  ReadLine();
  CheckLeftTurn(CheckTime);
  if(donus==3)
  {
    senaryo=3;
  }
}
void Senaryo3()
{
  ReadLine();
  CheckRightTurn(CheckTime);
  if(donus==4)
  {
    senaryo=4;
  }
}
void Senaryo4()
{
  ReadLine();
  CheckLeftTurn(CheckTime);
  if(donus==5)
  {
    senaryo=5;
  }
}
void Senaryo5()
{
  ReadLine();
  CheckRightTurn(CheckTime);
  if(donus==6)
  {
    senaryo=6;
  }
   
}
void Senaryo6()
{
  ReadLine();
  CheckLeftTurn(CheckTime);
  if(donus==7)
  {
    senaryo=7;
  }
   
}
void Senaryo7()
{
  ReadLine();
  CheckRight90Turn(CheckTime);
  if(donus==8)
  {
    senaryo=8;
  }
   
}
void Senaryo8()
{
  ReadLine();
  CheckRightTurn(CheckTime);
  if(donus==9)
  {
    RightTurn(TurnSpeed,TurnTime);
    senaryo=9;
  }
   
}
void Senaryo9()
{
  ReadLine();
 // CheckRightTurn();
   CheckLeftTurn(CheckTime);
  if(donus==10)
  {
    //RightTurn(TurnSpeed,TurnTime);
    //LeftTurn(TurnSpeed,TurnTime);
    senaryo=10;
  }
}
void Senaryo10()
{
  ReadLine();
 // CheckRightTurn();
  CheckRightTurn(CheckTime);
  if(donus==11)
  {
   // RightTurn(TurnSpeed,TurnTime);
   //LeftTurn(TurnSpeed+20,TurnTime);
    senaryo=11;
  }
}
void Senaryo11()
{
  ReadLine();
 // CheckRightTurn();
 CheckLeftTurn(CheckTime);
  if(donus==12)
  {
   // RightTurn(TurnSpeed);
    LeftTurn(TurnSpeed,TurnTime+75);
    senaryo=12;
  }
}
void Senaryo12()
{
  ReadLine();
  // CheckRightTurn();
  CheckLeftTurn(CheckTime);
  if(donus==13)
  {
    // RightTurn(TurnSpeed);
    LeftTurn(TurnSpeed,TurnTime+90);
    
    senaryo=13;
  }
}
void Senaryo13()
{
  ReadLine();
  GoStraight(StraightSpeed,StraightTime);
  CheckLeftTurn(CheckTime);
  if(donus==14)
  {
    
    senaryo=14;
  }
}
void Senaryo14()
{
  ReadLine();
  CheckRightTurn(CheckTime);
  if(donus==15)
  {
     RightTurn(TurnSpeed,TurnTime);
    senaryo=15;
    
    
  }
}
void Senaryo15()
{
  ReadLine();
  CheckRightTurn(CheckTime);
  if(donus==16)
  {
    RightTurn(TurnSpeed,TurnTime);
    senaryo=16;
  }
}
void Senaryo16()
{
  ReadLine();
  CheckLeftTurn(CheckTime);
  if(donus==17)
  {
    
    senaryo=17;
  }
  
}
void Senaryo17()
{
  ReadLine();
  CheckLeftTurn(CheckTime);
  if(donus==18)
  {
     
    senaryo=18;
  }
 
}
void Senaryo18()
{
  ReadLine();
  CheckRightTurn(CheckTime);
  if(donus==19)
  {
    
    senaryo=19;
  }
 
}
void Senaryo19()
{
  ReadLine();
  CheckLeftTurn(CheckTime);
  if(donus==20)
  {
    LeftTurn(TurnSpeed,TurnTime+75);
    GoStraight(70,400);
    senaryo=20;
    WhiteLine=1;
  }
 
}
void Senaryo20()
{
  ReadLine();
  CheckBlackLine();
  if(donus==21)
  {    
    senaryo=21;
  }
}
void Senaryo21()
{
  ReadLine();
  CheckLeft90Turn(CheckTime);
  if(donus==22)
  {  
    LeftTurn(TurnSpeed,TurnTime);
    senaryo=22;
    
  }
}
void Senaryo22()
{
  ReadLine();
  CheckLeft90Turn(CheckTime);
  if(donus==23)
  {  
    //LeftTurn(TurnSpeed,TurnTime+100);
    senaryo=23;
   
  }
}
void Senaryo23()
{
  ReadLine();
  CheckLeft90Turn(CheckTime);
  if(donus==24)
  {  
    
    LeftTurn(TurnSpeed,TurnTime);
    senaryo=24;
  }
}


void Senaryo24()
{
  CheckLeft90Turn(CheckTime);
  
  ReadLine(); 
  
  if(donus==25)
  { 
    
    LeftTurn(TurnSpeed,TurnTime);
    
    senaryo=25;
  }
}
void Senaryo25()
{
  CheckRight90Turn(CheckTime);
  ReadLine();
  
  if(donus==26)
  {  
    RightTurn(TurnSpeed,TurnTime+100);

    
    senaryo=26;
  }
}
void Senaryo26()
{
  ReadLine();
  CheckLeft90Turn(CheckTime);
  if(donus==27)
  {  
    LeftTurn(TurnSpeed,TurnTime);
    senaryo=27;
  }
}
// BEŞGENİN OLDUĞU YER
void Senaryo27()
{
  ReadLine();
  CheckLeftTurn(CheckTime);
  if(donus==28)
  {  
    LeftTurn(TurnSpeed,TurnTime);
    senaryo=28;
  }
}
void Senaryo28()
{
  ReadLine();
  CheckRightTurn(CheckTime);
  if(donus==29)
  {  
    //RightTurn(TurnSpeed,TurnTime+200);
    senaryo=29;
  }
}
void Senaryo29()
{
  ReadLine();
  CheckRightTurn(CheckTime);
  if(donus==30)
  {  
    //RightTurn(TurnSpeed,TurnTime+200);
    senaryo=30;
  }
}
void Senaryo30()
{
  ReadLine();
  CheckRightTurn(CheckTime);
  if(donus==31)
  {  
    //RightTurn(TurnSpeed,TurnTime+200);
    senaryo=31;
  }
}
void Senaryo31()
{
  ReadLine();
  CheckRightTurn(CheckTime);
  if(donus==32)
  {  
    //RightTurn(TurnSpeed,TurnTime+200);
    senaryo=32;
  }
}
void Senaryo32()
{
  ReadLine();
  CheckStraight();
  if(donus==33)
  {  
    //RightTurn(TurnSpeed,TurnTime+200);
    while(true)
    {
      MotorsSpeed(0,0);
    }
    senaryo=33;
  }
}




void GoStraight(int speed,int time)
{
  do
    {
      
      MotorsSpeed(speed,speed);
      
    }while(baslangicZamani+time>millis());
}
void WriteSensorValues()
{
  uint16_t position;
    if(WhiteLine==1)
    {
       position = qtr.readLineWhite(sensorValues);
    }
    else
    {
      position = qtr.readLineBlack(sensorValues);
    }
  
  for (uint8_t i = 0; i < SensorCount; i++)
  {
    Serial.print(sensorValues[i]);
    Serial.print('\t');
  }
  Serial.println(position);
  delay(250);
}
void ReadLine()
{
    if(WhiteLine==1)
    {
      Position = qtr.readLineWhite(sensorValues);
    }
    else
    {
      Position = qtr.readLineBlack(sensorValues);
    }
   
   Error = Position - 3500;
   Integral += Error;
 //  Integral = constrain(Integral, INTEGRAL_MIN, INTEGRAL_MAX);
   int Verify = Kp * Error + Kd * (Error - FinalError) + Ki * Integral;
   FinalError = Error;

   RightSpeed = RightBaseSpeed + Verify + ExtraSpeed ;
   LeftSpeed = LeftBaseSpeed - Verify +  ExtraSpeed ;

   RightSpeed = constrain(RightSpeed, -250, 250);
   LeftSpeed = constrain(LeftSpeed, -250, 250);
   MotorsSpeed(LeftSpeed, RightSpeed);
   
}
void MotorsSpeed(int RightSpeed, int LeftSpeed) {
  if (RightSpeed <= 0) {
    RightSpeed = abs(RightSpeed);
    analogWrite(Rpwm1, RightSpeed);
    digitalWrite(RDir1, HIGH);
    digitalWrite(RDir2, LOW);
  }
  else {
    analogWrite(Rpwm1, RightSpeed);
    digitalWrite(RDir1, LOW);
    digitalWrite(RDir2, HIGH);
  }
  if (LeftSpeed <= 0) {
    LeftSpeed = abs(LeftSpeed);
    analogWrite(Lpwm1, LeftSpeed);
    digitalWrite(LDir1, HIGH);
    digitalWrite(LDir2, LOW);
  }
  else {
    analogWrite(Lpwm1, LeftSpeed);
    digitalWrite(LDir1, LOW);
    digitalWrite(LDir2, HIGH);
  }
}


void CheckBlackLine()
{
   if(sensorValues[0]<200 &&sensorValues[1] <200 &&sensorValues[2]<200&&sensorValues[3]>700&& sensorValues[4]>700 &&sensorValues[5]<200 &&sensorValues[6]<200&&sensorValues[7]<200)
   {
      WhiteLine=0;
      donus++;

     
   }
}
 


void CheckRightTurn(float checkTime)
{
    
    if(sensorValues[1]>900 &&( (millis()- baslangicZamani) >=checkTime  ) )
    { 
      
      baslangicZamani=millis();
      donus++;
      
    }
    
}
void CheckRight90Turn(float checkTime)
{
    
    if(sensorValues[1]>900&& sensorValues[0]>900 &&( (millis()- baslangicZamani) >=checkTime  ) )
    { 
     
      baslangicZamani=millis();
      donus++;
      
    }
    
}
void CheckLeft90Turn(float checkTime)
{
    
    if(sensorValues[7]>900&& sensorValues[6]>900 &&( (millis()- baslangicZamani) >=checkTime  ) )
    { 
      
      baslangicZamani=millis();
      donus++;
      
    }
    
}
void CheckLeftTurn(float checkTime)
{
    if(sensorValues[6]>900 &&( (millis()- baslangicZamani) >=checkTime  ))
    {
      
      baslangicZamani=millis();
      donus++;
      
    }
}


void RightTurn(int turnSpeed,int turnTime)
{
     int startTime=millis();
        do
        {
          
          MotorsSpeed(turnSpeed,-turnSpeed);
          
        }while(startTime+turnTime>millis());
}
void LeftTurn(int turnSpeed,int turnTime)
{
     int startTime=millis();
        do
        {
          
          MotorsSpeed(-turnSpeed,turnSpeed);
          
        }while(startTime+turnTime>millis());
}



void CheckStraight()
{
    int baslangicZamani=millis();
     
     if(sensorValues[0]>700 &&sensorValues[1] >700 &&sensorValues[2]>700&&sensorValues[3]>700&& sensorValues[4]>700 &&sensorValues[5] >700 &&sensorValues[6]>700&&sensorValues[7]>700)
     {
        
        do
        {
          
          MotorsSpeed(150,150);
          
        }while(baslangicZamani+100>millis());
        
         donus++;  
     }
}

void Stop()
{
  while(true)
  {
    MotorsSpeed(0,0);
  }
}


void Blink() {
  for (int i = 0; i < 10; i++) {
   // digitalWrite(Led, LOW);
    digitalWrite(Buzzer, LOW);
    delay(180);
   // digitalWrite(Led, HIGH);
    digitalWrite(Buzzer, HIGH);
    delay(180);
  }
  digitalWrite(Buzzer, LOW);
}
2

Failure to properly tune the PID algorithm, and manually interfering with PID operation. With your approach, the robot behavior will be nearly impossible to predict or correct.

A web search with the phrase "pid tuning" will turn up tutorials on how to do the tuning correctly, and give a decent chance of success.

3

I think my PID algorithm is working properly. If it wasn't, the error could be anywhere at any time. As I said, the program gives this reaction after running for a certain period of time. As a result of the research I did on the internet, it is said that this error may be due to the accumulation of integral error. But the effect of the integral error on the line-following robot is negligible. I try again by resetting the Ki coefficient and it behaves the same. During the week, I will do a reset over the general error and see what happens.

4

No, sorry. It is obvious that you have not properly tuned the algorithm.

Good luck with your project!

5

Always unsigned long integers to store millis() results...
Why do you need so many scenarios???

6

Always use subtraction to see if time is over. This will have rollover problems.
while (startTime > millis() - turnTime) {
Consider PD control. At least you won't have integration windup.
(Set i=0).

7

CheckTime and many others should probably also be unsigned integer type.

8

I solved the problem by using unsigned long variable. thank you. But I don't understand why this happens, is there a logical explanation?

9

while(baslangicZamani+time>millis())
If baslangicZamani is defined as int, it cannot hold a value larger than 32768. (So already after 32 seconds).
After that it will rollover to a negative value...
And that value + whatever is stored in time will not easily be larger than millis....
Especially if time also goes to negative...
Using unsigned numbers and subtracting
prevents rollover problems...
Long unsigned prevents missing a rollover if you do not check at least 2 times per minute...

10

Actually, I thought this might be the case, but I assumed that the int value would be like in c#.c++ values are very different.It is useful to review the basics. Thanks again.

11

In c++ the size of int is system dependent...
On uno it is 16 bit
On mac it is 32 bit