Analog Wall Following Robot

This is a wall-following robot made using only analog electronics. 

This is developed for the semester 3 project under EN 2091: Laboratory Practice and Projects.

Introduction

• Wall following robot is a robot that follows a wall and travels keeping a constant distance from the wall. 

• Wall following is a common task in many robotics competitions.

• But the interesting thing is our project was to build a robot that travels on the centerline between two walls, using only analog electronics. That means we couldn’t use microcontrollers.

Working Concept

• The distance from the robot to the side walls is measured using two sharp IR sensors.

• The difference between the sharp IR is taken as the error signal and fed into a PID control circuit.

• The PID output signal is fed to the adder and subtractor circuits.

• Two PWM signals with varying duty cycles are generated using the PID output and a comparator circuit.

• Then using the motor driver, PWM signals are fed to the left and right wheels.

• The robot tracks the walls and travels on the centerline between the walls.

• Additionally, we added another sharp IR sensor to the front of the robot to control the speed of the robot.

• The measured distance is compared with a predefined distance and the difference is taken as the error signal.

• The error signal is fed to a PID control circuit.

• A PWM signal is generated using the PID output and a comparator circuit.

• This PWM signal acts as the Base speed of the robot.

• Consequently, the additional sharp IR sensor will vary the speed of the car accordingly.

Sub Circuits and Tasks

✅Instrumentation Amplifier- Reduce noise in Sharp IR sensor outputs and amplify signals

✅PID circuit- Control the error signal smoothly using feedback

✅Adder & Subtractor- Generate two PWM signals with varying duty cycles according to PID output

      💠Motor 1= base speed + PID output

        💠Motor 2= base speed - PID output

✅PWM circuit- Generate two different comparator voltages for the two motors

  💠Motor 1 duty cycle ∝ base speed + PID output

    💠Motor 2 duty cycle ∝ base speed - PID output

✅Voltage Regulator- To get 3.3V and 5V for required parts accordingly

✅Speed Selector- Manually control the base speed

Gallery

Team

GitHub Link- https://github.com/LasithaAmarasinghe/Analog-Wall-Follow-Robot