Robot linea

Robotics Workshop Currents 15th march 2008 EEE Department NIT Trichy

Developed By: Mayur Agarwal Prashant Agrawal Krishna Nand Gupta Hitesh Meghani

To Our Readers
We are glad to have had an opportunity to share our knowledge with interested robotics enthusiasts. In this book we have attempted to provide a brief compilation of our experiences in robotics (participating and winning inTechnical Festivals all over the country), extending over last three years. The prospect of practically implementing engineering concepts is the hallmark of robotics. By reading the basics in this book you will gain a significant insight into various tools employed in shaping a robot. However to participate in technical festivals with ever changing problem statements you will be required to apply thesebasics concepts and come up with innovative algorithms and superior designs. Do not expect this book to be a panacea for all robotic problems, rather you will have to sit and work for hours to get a functioning robot. Transform each failure into a stepping stone instead of stumbling over it. We appreciate the beauty of diamond but little do we wonder how it became so bright? Its perseveranceextending thousands of years transformed it into its present sparkling state. We encourage you to plunge further into the field of robotics with dedicated perseverance, make your own mistakes and gain valuable experience from them. ALL THE BEST

Your valuable suggestions and inquisitive doubts are welcome. You can contact us at

Mayur Agarwal (mayurmagic.nitt@gmail.com ) Krishna Nand Gupta(kng_sweet94@yahoo.com) Prashant Agarwal (pras_nitt@yahoo.co.in Hitesh Meghani (h.nittian@gmail.com ) )

 

Introduction
The line follower is a self operating robot that detects and follows a line that is drawn on the floor. The path consists of a black line on a white surface (or it may be reverse of that). The control system used must sense a line and maneuver the robot to stay on course, whileconstantly correcting the wrong moves using feedback mechanism, thus forming a simple yet effective closed loop System. The robot is designed to follow very tight curves.
   

Sample Paths
The path is a black line on a white background with width of 3 cm (except at bends where a little variation may be present). It may contain paths laterally displaced by a around 3 cm and also gap of at most 5cm. (All these specifications may vary one competition to other).
   
 

 

 
 

Figure 1: Basic Sample Arena 

 

   Figure 2: Sample Arena of Kurukshetra’08 (Anna University)   

 

 
 

Figure3: Sample Arena of Pragyan’07 (NIT Trichy) 

Figure4: Sample Arena of Robo‐Relay of Kishitij’08 (IIT KGP) 

    From above images we can conclude that in most of line follower competitions, we have to perform  some additional task apart from following the line.   

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Basic design and requirements
The robot is built with ATmega8L, L293D,IR sensors,LM324 , platform consisting of a toy car chassis (or hand made Al sheet chassis). The robot is designed using two motors controlling wheels. It has infrared sensors on the bottom for detect black tracking tape .It capturesthe line position with the help of these optical sensors called opto-couplers mounted at front end of the robot. (Each opto-coupler consists of an IR LED and an IR Sensor) when the sensors detect black surface, output of comparator, LM324 is low logic and for white surface the output is high. It reports to the microcontroller for accurate control and steering of motors. Microcontroller ATmega8Land Motor driver L293D were used to drive the motors.

Basic operation
The basic operations of the line follower are as follows: 1. Capture line position with optical sensors mounted at front end of the robot. For this a combination of IR LED’s and Photo Transistor called an optocoupler is used. The line sensing process requires high resolution and high robustness. 2. Steer robot...