Line following without skid steering

[littletim979]

I want to program my robot to follow a line like this:http://youtu.be/Uef5HNlWLP4
I've been trying a lot of things and really am confused at how he did it. My robot can be seen here:http://mindstormspodcast.wordpress.com/ ... t-car-2-0/ (the last picture shows the attachments that i made, including the light sensor at the end of the beam)
Any help is appreciated, thanks.

[jwiger]

From the youtube video it looks like he has the color sensor and ultrasonic sensor steered by the same servo. When he first starts it you can see it turn the color sensor all the way to the right. My guess is he does that to establish the angle. He turns it, resets the angle to zero, then knows how many degrees is straight forward. After that it starts sweeping left and right, and the car drives with left, centered, or right steering.

[littletim979]

Does anyone have any ideas about line following with a car that isn't skid steering? It doesn't have to be scanning like he one shown in the video but it would be great if i could be because it seems like the fastest line followers are like that. Also, jwiger, it seems like it is more complex than that since it isn't just 3 defined spots but I've been having trouble with the scanning in general anyways, one of my problems is that it will go past the line with out seeing it and then loose it because it keeps wanting to go the other direction, but thanks for the help anyways.

[hassenplug]

Here's another approach to consider:

https://www.youtube.com/watch?v=w5dTUlj3HJQ or https://www.youtube.com/watch?v=LCQEP6vAN_I

Not exactly the type of steering you're looking at, but the basic idea is to mount the light sensor(s) on the steering motor, that way when the line moves, the sensors move, and the steering turns.

Does that make sense?

Steve

[littletim979]

Both of those robots shown use more than 1 sensor but I get the idea. My main problem as been that the sensor sometimes doesn't see the line and then keeps turning the wrong way, but I've moved onto a different robot know - thanks anyways