Subject:
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Re: Rack-and-pinion steering line tracker
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Newsgroups:
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lugnet.robotics
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Date:
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Sat, 8 Jan 2000 02:11:41 GMT
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Viewed:
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710 times
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In lugnet.robotics, "Simon Bogaert" <Simon.Bogaert@advalvas.be> writes:
> Is it possible to build a rack-and-pinion steering controlled by the
> RCX without using a sensor input?
One of my first bots was a R&P steered car that drove around randomly and used
a front bumper to escape trouble (what I really wanted was a rotation sensor to
detect stalls, but they haven't arrived yet!). The obstacle avoidance
algorithm was stop drive/stop random steering task/center wheels/reverse a
bit/restart the random steering task/go! Centering was accomplished by driving
the motor the rest of the way in one direction, then reversing and doing
Wait(35), which was just long enough to center the wheels. The gearing was 1
24t clutch gear on the motor, driving an 8t on a long axle running to the 8t on
the rack. I happened to use one of the tubular tilt-steering racks, but it
would work the same with any of the many LEGO designs...
One design I've been considering would use the same clutch arrangement, but
include a stop which would prevent continuous rotation past the center point.
So you turn on the steering motor heading towards center, it stalls at the
center, then you turn off the motor and turn it back on to resume the motion.
My fuzzy idea right now involves a stopper cam that has a rubber band
retracting it, attached to a clutch gear. When the steering motor starts, it
forces the cam into position and then the clutch starts spinning. The steering
axle has an arm which hits the cam and then the OTHER clutch gear stalls. When
the RCX drops power, the rubber band drops the cam out of the way. When it
starts going again, the arm moves past the cam before it can drop.
If you just want to save a sensor input, you could use the old trick of
piggybacking a touch sensor on a light sensor.
--Ben
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Message has 1 Reply:
 | | Re: Rack-and-pinion steering line tracker
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| (...) If you have the Space Shuttle kit, it includes a gear-box that changes gears and some switches that change between forward, reverse and off polarity. Either could be used with a bumper to control the steering motor of a rack and pinion system. (...) (25 years ago, 8-Jan-00, to lugnet.robotics)
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Message is in Reply To:
| | Rack-and-pinion steering line tracker
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| I'm trying to get the 8479 Truck following (the edge of) a line. It drives around the whole room, except it doesn't follow the line (RIS 1.5 Test Pad). Is it possible to build a rack-and-pinion steering controlled by the RCX without using a sensor (...) (25 years ago, 7-Jan-00, to lugnet.robotics)
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