Subject:
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Re: Steering Drive
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Newsgroups:
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lugnet.robotics
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Date:
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Wed, 25 Aug 2004 05:34:22 GMT
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Viewed:
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952 times
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"Jon Gilchrist" <robots@DEELEETEf3p.com> wrote in message
news:cmsni0t76f5vr92g29g4d7ecg6gbu5r60i@4ax.com...
> So I'm building this robot because my FLL kids told me it couldn't be
> done. It has to do a few things, line following, bumpers, nothing too
> special. I made it with a steering drive because it has to have
> wheels that turn to make it look right (I'll explain after it's done,
> I have to keep the design a secret for another 2 weeks). Not a big
> problem, I'm using the basic linkage that came with the racers
> (8473-1) I got at the Brickfest outlet store sale. I've got a
> differential in there with a motor to drive it, and a rotation sensor
> hooked up for distance measuring. I have a light sensor for finding
> the line I'm going to follow. Here's the tricky part. I have a touch
> sensor hooked up much like this one
> (http://www.marioferrari.org/brlm/f1614.jpg) so that I can tell when
> the wheels are pointed straight ahead.
>
> So my problem is, how do I tell which way I need to turn the motor to
> get the wheels back to straight?
>
> If the sensor is touched, I know that it is going straight, but if the
> sensor is not touched I can't figure out any good way to tell which
> side of the switch the cam is on. At least, not without using another
> sensor port, which I don't have available. I can't double up on the
> light sensor, because I can't have the sensor value go to 100 just
> because I'm going straight.
I don't understand why you need to know which way to turn the wheels to go
straight?
When you initialize the robot you can test with low power first some seconds
in one direction and then the other way until you reach center and the tuch
sensor is pressed. You probably need to use the clutch gear to protect the
steering mechanism. Now its just all about having two flags in the
programming that tells you what direction you last turned the wheels. Eg.
set flag 1 if you turn right, and set flag 2 if left was the last direction
and both flag reset when center. Then you can just check which flag was set
and the tuch sensor to know if the wheels is to the right, left or center...
Or do I miss some function in your robot? Do you want to know HOW much the
wheels are turned and in what direction?
Regards
Øyvind Steinnes
http://www.brickshelf.com/cgi-bin/gallery.cgi?m=Phoenix
>
> Help. Any advice appreciated.
>
> -Jon
>
>
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Message has 1 Reply:
 | | Re: Steering Drive
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| Hi, I have used this flag technique successfully. It was easier than a hardware solution. I use leJOS which also provides a way to check which direction the motor is turning. When the touch sensor is hit, you can do something like if ( (...) (20 years ago, 26-Aug-04, to lugnet.robotics)
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Message is in Reply To:
| | Steering Drive
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| So I'm building this robot because my FLL kids told me it couldn't be done. It has to do a few things, line following, bumpers, nothing too special. I made it with a steering drive because it has to have wheels that turn to make it look right (I'll (...) (20 years ago, 25-Aug-04, to lugnet.robotics)
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