Cytron Technical Forum

Hello . I am very interested in building line follower which I want to use it as maze solver .
However I experience some problem which my robot always go out of the line if I set it to high speed .
But if I turn it down it will lost too much speed . Therefore I have read your PID line follower in tutorial section .
But i am using my own PCB design IR sensor . So what I want to know is how do I set my set point for this particular case ?
And how do I read my current position ?

Hi newroboticist,

To implement PID into your line following robot, 1st you need to know the error. Since you are building your own sensor, you need to set a linear value from your sensor. Let say the most left sensor is 0, and the most right sensor is 100. So the center point is 50. Of course you need to do some calculation to obtain that. Once you get the error, you can create the PID.

Anyway, there have more factors that cause your robot "go out of the line" in high speed. Try to fix/improve the hardware and mechanism first before proceed into PID in programming.

Thanks.

Ohh . Now i get the idea of that . And for the PID constant value , is there any good value to be used , I mean for initital test .
And may I know what software you used to plot the graph in the PID tutorial section ?

Normally in line following mobile robot, we're not using I, means PD only. So first set P, run the robot, see the response, and then set D to improve it. Honestly there don't have 'good constant PID value' for this. Different mechanism have different tune. Even the robot is same, the PID is not necessarily the same.

Sorry, I'm not sure which tutorial do you refer. Could you share the link?

Thanks.

Oh I see . So it means the rpm of motor and the robot dimension plays the role in determining the constant PID right ?
Okay thx for the hints . Gonna try it .
I saw that in this link
http://tutorial.cytron.com.my/2012/06/2 ... ed-design/

Hi, from that tutorial, they using excel software for plotting graph.

P/S: Any findings, please share with us. Thanks.

Oh excel . I thought they use the data direct from the arduino .
Haha . Will do so if I get the information .