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INTRODUCTION
A robot obstacle detection system comprising: A Robot housing which navigates with respect to a surface; a sensor subsystem having a defined relationship with respect to the housing and aimed at the surface for detecting the surface. The sensor subsystem including: An optical emitter which emits a directed beam having a defined field of emission, and a photon detector having a defined field of view which intersects the field of emission of the emitter at a finite region; and a circuit in communication with the detector for redirecting the robot when the surface does not occupy the region to avoid obstacles.
Obstacle sensors are nothing but the IR pair. As the transmitter part travel IR rays from to receiver here also transmitter send the data receiver but these IR pair are places beside each other. So whenever the obstacle sensor got an obstacle in between its way the IR rays reflects in a certain angle.
PROJECT BRIEF
AIM
The aim of this project is to design an “DIFFERENTIAL DRIVE ROBOTIC ROVER”
In this project mainly when ever robot senses any obstacle automatically diverts its position. Robot consists of two motors, which control the side pair wheels of each and help to move left or right or backward and forward and follow its path. Robot senses the object with help of obstacle sensor. IR pair is used for detecting the obstacle. The two basic parts for working with IR are the emitter and the detector. The emitter is typically an LED that em ts near-infrared light.
In this project we develop a robot such that it will be moving according to path assigned to it if at all there is any obstacle in between then the robot stops and change its direction. This sort of project is very much useful in the industries where the automated supervision is required.
OBJECTIVES
 To have basic idea about IC L293D DC motor control.
 To understand the working and construction of the Obstacle
Avoidance Car.
 To have an idea about Microcontroller.
 Knowledge in selection of components according to the function
and requirements.
 To have a basic idea in Mechatronics System Design.
 Exposure in trying out new methods and rectification of the system.
 Troubleshooting where ever necessary.
PROJECT TARGET
” To construct an Obstacle avoidance car using Motor controller IC.”
PROJECT LIMITATION
 Separate power sources are required to control the Motor and
Motor controller IC.
 To have a basic idea in Mechatronics system design.
 New methods and rectification of the system.
PROJECT DETAILS
PROJECT RELEVANCE
In robotics, obstacle avoidance is the task of satisfying some control objective subject to non-intersection or non-collision position constraints. Normally obstacle avoidance is considered to be distinct from path planning in that one is usually implemented as a reactive control law while the other involves the pre-computation of an obstacle-free path which a controller will then guide a robot along. A practical real-time system for passive obstacle detection and avoidance is presented.
In this project mainly when ever robot senses any obstacle automatically diverts its position to left or right and follows the path. Robot consists of two motors, which control the side pair wheels of each and help in moving forward and backward direction. Robot senses the object with help of obstacle sensor. IR pair is used for detecting the obstacle. The two basic parts for working with IR are the emitter and the detector. The emitter is typically an LED that emits near-infrared light.
DESIGN STEPS
BLOCK DIAGRAM
The above shown is the block diagram for the Differential Drive Robotic Rover. It consists of five modules.
1. Power Supply Unit
2. Battery Charger Unit
3. IR Sensor Circuit
4. Microcontroller Unit
5. Motor Driver and DC Motor Assembly unit
These are the hardware of the project.
BLOCK DIAGRAM DESCRIPTION
1. POWER SUPPLY UNIT:
Power supply is a supply of electrical power. There are many types of power supply. Most are designed to convert high voltage AC mains electricity to a suitable low voltage supply for electronic circuits and other devices. A power supply can break down into a series of blocks, each of which performs a particular function.
For the working of the Differential Drive Robotic rover we require two voltage ranges.
1. 5V Supply for Sensor and Microcontroller circuit.
2. 12V Supply for the motor driver circuit.
Since the Rover is moving we can’t use the supply directly from the mains. We require a Battery and a charger to charge the battery. We requires 12V battery charger to charge the battery. We also require a power source of 5V to give to the IR Sensor Circuit and to Microcontroller. For this we require a 5V source. Since we are having a 12V supply we can take a parallel connection using a 5V voltage regulator.
POWER SUPPLY WORKING:
The transformer is 230V AC supply. Transformers work only with AC and this is one of the reasons why mains electricity is AC. We are using steps down transformer because to step down high voltage AC mains to low voltage AC (i.e.; 230V to18V). This transformer fed into rectifier. In bridge rectifier there are several ways of connecting diodes to make a rectifier to convert AC to DC and it is most important and it produces full-wave with varying DC so that we go for smoothing capacitor it smooth the DC from varying greatly to a small ripple. But here also small ripple is there. By using regulator we can eliminate the ripple. In regulator to set DC output to a fixed voltage.