Subject:
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Re: My Latest Creation
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Newsgroups:
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lugnet.org.us.laflrc
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Date:
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Mon, 19 Sep 2005 21:18:28 GMT
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Viewed:
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1038 times
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In lugnet.org.us.laflrc, Steve Hassenplug wrote:
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So, it has a motor to steer in addition to the drive motors? Is there a
reason for not using the build-in steering? Oh, I guess for future
development. (RCX Controlled)
Would it be possible to have the polarity switch so it will “un-steer” the
front wheels until they are centered? Like have a rubber band pull the
polarity switch towards the side (same side as the gear rack), which causes it
to drive the steering to the center. When it’s back to center, the rubber
band stops pulling. When you are actually turning, that will overpower the
rubber band and turn the direction you want. You should also (if you haven’t
already) be able to put a stop, that returns the polarity switch to neutral,
when the steering reaches the end of travel.
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Yes, there is a standard Lego 9V motor for the steering. It is connected
directly to the rack with a 12 tooth gear.
The buggy controller is really well suited for hooking a polarity switch up to
it directly. The axel output for steering is positioned as an “x” in the
off/centered position. This corresponds to the off position of the polarity
switch. The controller moves 45 degrees each direction in the on/turning
position and this corresponds to the on positions of the polarity switch.
Using the polarity switch to recenter the steering seems elaborately complicated
as it involves getting that silly switch to turn on and off at an exact
position. However, I was considering some way to mecahnically return the rack
to center when it wasn’t under power one way or the other from the motor drive.
I didn’t look at this real hard because having the steering stay in a fixed turn
has advantages when it is being controlled by an RCX.
As for stopping at a center point for going straight, I managed to do this on a
previous rack & pinion design using one of Hi-Technics sensors (EO I think...the
gray & red one). I simply used the sensor to monitor the distance away a marker
block (white) mounted to the rack was at. At the time, I was using it to detect
when the steering was hard left or hard right so I would stop driving it, but it
worked for centering too...I just didn’t have a need to center after the robot
started.
As for why I didn’t hook the steering drive up directly, there were 2 reasons.
You stated one (ability to change over to an RCX). The other is that with only
1/4 of a turn for full side-to-side steering, I would have to gear the output up
some and then drive with a 40 tooth gear...and I used all my gears to do the
drive train :) (there are 20 gears + 2 differentials in the drive train...I
never said this thing was simple) :)
Hope that all makes some sense.
B
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Message has 1 Reply:
 | | Re: My Latest Creation
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| (...) Bryan... I'd be interested in knowing how you have your drive train setup. I'm sure it is too complicated to easily explain... Maybe a couple of pictures? I've tried a few RC buggy motor drive vehicles and have found that trying to send all (...) (19 years ago, 20-Sep-05, to lugnet.org.us.laflrc, FTX)
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Message is in Reply To:
| | Re: My Latest Creation
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| (...) Sounds nice. So, it has a motor to steer in addition to the drive motors? Is there a reason for not using the build-in steering? Oh, I guess for future development. (RCX Controlled) Would it be possible to have the polarity switch so it will (...) (19 years ago, 19-Sep-05, to lugnet.org.us.laflrc)
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