Arduino Two-Wheel Self-Balancing Robot

 Design and Implementation of an Arduino-Based Two-Wheel Self-Balancing Robot

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🔷 Abstract

A two-wheel self-balancing robot is a robot that maintains its upright position using feedback from motion sensors. This project uses an Arduino UNO, an MPU6050 accelerometer & gyroscope, and DC motors to continuously measure the tilt angle and correct it using a PID control algorithm. The robot behaves like an inverted pendulum and balances itself in real time.

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🔷 Objectives

• To design a self-balancing robot using Arduino

• To understand gyroscope & accelerometer sensors

• To implement PID control

• To control motors using motor driver

• To study real-time feedback systems

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🔷 Block Diagram

MPU6050 Sensor → Arduino UNO → PID Controller → Motor Driver → DC Motors

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🔷 Components Required

🔹 Hardware

Component	Quantity
Arduino UNO	1
MPU6050 (Gyro + Accelerometer)	1
L298N / L293D Motor Driver	1
DC Gear Motors	2
Robot Chassis + Wheels	1 set
18650 Battery / 12V Battery	1
Buck Converter (optional)	1
Jumper Wires	As required
Power Switch	1

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🔷 Working Principle

• The MPU6050 measures tilt angle (pitch).

• Arduino calculates error between current angle and setpoint (0°).

• PID algorithm calculates motor speed correction.

• Motors rotate forward or backward to balance robot.

• This loop runs hundreds of times per second.

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🔷 Circuit Connections

🔹 MPU6050 → Arduino

MPU6050	Arduino
VCC	5V
GND	GND
SDA	A4
SCL	A5

🔹 Motor Driver (L298N) → Arduino

L298N	Arduino
IN1	D5
IN2	D6
IN3	D9
IN4	D10
ENA	D3 (PWM)
ENB	D11 (PWM)

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🔷 Arduino Code (Basic Working)

#include <Wire.h>
#include <MPU6050.h>

MPU6050 mpu;

float angle, error, lastError;
float Kp = 18, Ki = 0.8, Kd = 0.9;
float integral, derivative;
float setPoint = 0;

void setup() {
  Wire.begin();
  mpu.initialize();
  pinMode(3, OUTPUT);
  pinMode(5, OUTPUT);
  pinMode(6, OUTPUT);
}

void loop() {
  angle = mpu.getAccelerationY() / 16384.0 * 90;
  error = setPoint - angle;

  integral += error;
  derivative = error - lastError;

  float output = Kp * error + Ki * integral + Kd * derivative;
  lastError = error;

  motorControl(output);
}

void motorControl(float speed) {
  speed = constrain(speed, -255, 255);
  if (speed > 0) {
    digitalWrite(5, HIGH);
    digitalWrite(6, LOW);
  } else {
    digitalWrite(5, LOW);
    digitalWrite(6, HIGH);
  }
  analogWrite(3, abs(speed));
}

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🔷 Output

• Robot stands upright automatically

• Maintains balance when pushed slightly

• Corrects tilt in real time

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🔷 Advantages

✔ Real-time control system
✔ Educational (PID, sensors, robotics)
✔ Low cost
✔ Expandable (Bluetooth, obstacle avoidance)