Monday, November 11, 2013

LINE FOLLOWING ROBOT - II

 
THE MOTOR DRIVE SYSTEM


Hello again. Earlier we discussed about the sensor panel of the line following bot and from this article I'm going to explain about the motor drive system of this bot.

Here the motor drive system is based on the L298 IC.  L298 IC is a high voltage, high current dual  full-bridge driver. Two separate motors can be connected to these two H-Bridges.                                                           



                            

                               Figure 1 - L298 IC                                              Figure 2– H- Bridge

                                                     


Figure 3- Motor Drive Circuit connected to L298 IC



Here there are two separate input couples for the two motors. And along with the inputs, there are two enable pins to operate the two motors.  Two  enable inputs are provided to enable or disable the device independently of the input signals. i.e. even though  In1 and In2 receive logic ‘1’, the motor still does not operate until EnA enable pin receives a logic ‘1’.



                         Table1 – Motor Behavior according to the given inputs




Motor Behavior
EnA = 1
In1 = 1    In2 = 0
In1 = 0    In2 = 1
In1 = In2

Turn to Right
Turn to Left
Sudden Stop
EnA = 0
In1 = 1 or 0
In2 = 1 or 0
The motor rotates freely or stay at rest



   





   



 Here In1,In2 and EnA  inputs are to control motor 1. The motor 2 is controlled by In3,In4 and EnB. Two outputs from Pin2 and Pin3 of the IC are taken to connect motor1 and motor 2 is connected to the outputs taken from Pin 13 and Pin 14. When connecting these outputs taken from the IC to the motor, D1, D2, D3 and D4 free willing diodes also should be connected to the motor. For this purpose fast recovery diodes should be selected. Here we have used 1N4148 diodes.




Figure 4 –The Final Motor Driver Circuit



From the female ports included in the circuit as shown, the two motors and inputs can be connected.

So I guess you got some idea about the motor drive system and thank you for reading.


2 comments:

  1. Hmm
    I think it should be 1N4148, not 1N4048 (which is 275A rectifier)

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    Replies
    1. I think u are correct and thank u very much for telling me about the mistake..
      I will correct it..

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