PID line follower (actually "PD")

Projects General Guidance
1

I'm really sorry to ask this here, probably this is really simple stuff for must of you, but I've been researching on how to program a line follower using a PID algorithm, for the past two months, and still haven't come up with anything useful.

I would like to be able to use a color sensor to follow the line and nothing else. That's just for efficiency and simplicity. I could use IR sensors (and/or whatever) if needed.

Could you guys give me any hints or good tips on how to get started?

The car only needs to follow a line (black on white bg or vice-versa) and take sharp 90 degree turns. I could achieve this with a simple back-and-forth program, but I'm really trying to create something more ellegant and learn the tools to possibly use on something more complicated in the future.

REALLY thanks, in advance.

2

For sensible steering, you need to know whether the vehicle is veering to the right or left of the line, and most people use 3 to 7 IR or B&W sensors. What "color sensor" did you have in mind?

I've seen line followers that use a single point sensor, and the wobbling movement required to find the line is anything but elegant.

3

I had TCS3200 in mind. But OK, I could scratch that idea. Let's go with IRs.

Is there a particular library I should use?

4

I have long thought that the thing should be called IPD rather than PID because the I-Term seems to be the most important. It keeps track of the accumulated error. In a line following system the I-Term would be zero when the device is on track, but that does not mean it is irrelevant.

...R

5

Don't worry about the library until you have the robot finished. The coding is the easiest part of the project.

Pololu is a good source of parts and ideas.

6

Thank you!

I put together a prototype, three IR, h-bridge, two DC motors, dummy wheel and UNO. Will move to 5 IR if this works.

Where should I start reading about the code?

7

Google "line following robot" for countless tutorials. Add the search term arduino for specific code examples.