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Author Topic: I encounter a problem in my robot and need your help  (Read 860 times)

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Offline ahmed_nussairTopic starter

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I encounter a problem in my robot and need your help
« on: August 25, 2012, 10:36:03 PM »
Hi Everybody,

I am building my very first robot (line follower robot) and I am about to finish it. I built my sensor successfully and I am ready to make the wheels move according to the readings of the sensor.

But I encounter a problem. When I tested the movement of my robot, I saw the robot didn't move with applying 5V to 9V to the motors. I mean I get the wheels hardly move and when I lift the robot from the ground, I get the the motors work and spin quickly.

When I apply a 12V to the motors, the robot sometimes moves and sometimes does not.

I wish I can find the reason that makes my line follower robot not moving:

- Do I need a motor with high torque? Do I need to change the motors? (The motors I used in my very first robot look like this)
http://comlark.ru/img/32446.JPG

- Do I need a wheel with some other material rather than the rubber? (I use the rubber wheel for my robot and the wheels look like that type)
http://shop.rotor.com.sg/images/Product/23316/size.gif

Also, the wheels diameter is up to 1.75 inch.

- Does the friction between the wheels and the ground cause the robot not moving?

- Or what is the reason?

Offline waltr

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Re: I encounter a problem in my robot and need your help
« Reply #1 on: August 25, 2012, 11:52:25 PM »
Are the wheels directly connected to the motor's shaft?
If so then that is the problem.
For robots (or any vehicle) directly driven from a motor does not work. What is required is a gear box or other method to decrease the rpm (speed) of the motor to the wheels. This also increases the Torque applied to the wheels.

When you lift the robot off the ground with power applied to the motors, how fast do the wheels turn? I'll bet they turn very fast.

If you don't have a gear reduction box to fit onto the motors then there is another way to get a speed reduction and increase the torque.
1st- mount the wheels on a shaft so then turn freely and support the robot.
2nd- mount the motors so that the motor shaft is pressed against the outer tire of the wheel. (the wheel and motor shafts are parallel).
This will give a reduction ratio that is proportional to the ratio of the wheel diameter to the motor shaft diameter.

Offline ahmed_nussairTopic starter

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Re: I encounter a problem in my robot and need your help
« Reply #2 on: August 26, 2012, 12:02:13 PM »
Thanks for your help ..


 


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