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Subject: 
Re: What are you making?
Newsgroups: 
lugnet.robotics
Date: 
Mon, 9 Nov 1998 07:21:10 GMT
Original-From: 
Doug Carlson <dcarlson@%StopSpam%net-info.com>
Viewed: 
2756 times
  
Doug Carlson wrote:

Hello folks,  time to de-lurk for a few minutes ...

I've been tweaking the mechanical details of a syncronous-drive robot base
that I began tinkering with about a year ago. The unit presently has four
wheels
that are driven by one Technic motor and steered syncronously by a second
Technic
motor. This enables the chassis to remain oriented in the same direction and
yet travel
in any direction with zero tuning radius. I used four of the large turntable
elements to
mount the drive wheels. The turntables are inverted from their normal
orientation
to use the large gears for steering. The wheels are driven by a vertical axel
though
the center of each turntable with 12T bevel gears driving the wheel-axle. Each
wheel
is also offset from the center of its turntable so that rotating the turntable
only causes
the wheel to travel in an arc around the same spot. I've driven just the
steering motor
and the base only wiggles a small amount as all four wheels run in circles
below. :-)
It also has angle sensors
on each drive system to keep track of distance and direction. This only leaves
one sensor
port open on the RCX without multiplexing of some type so I'm still not sure
where that's headed.
One possibility is a turret that is driven off the steering system with a light
sensor on it to
"see" things in it's path. I've tried using the light sensor and touch sensor
together on the same
input port with good results so I could add touch sensors to the main chassis
also.
This is all still in the hardware stage but the results so far are quite
encouraging.  :-)
I'll put some images on my web page soon for those more curious about the
mechanical
configuration.

-- Doug

Doug Carlson
dcarlson@net-info.com
http://www.net-info.com/~dcarlson



Pictures are now up on my web page near the bottom - just look for the RCX.   :-)
The base works quite well. I used NQCC to program the RCX and it now runs in almost
perfect squares. Really cool.
I'll have to do more with it later but this was a first stab at using NQCC  (many
thanks to Dave Baum for this gem).

-- Doug



Message is in Reply To:
  re: What are you making?
 
(...) about (...) Cool :) It also going to give you a different sort of coordinate space and mapping when it comes to the software. Something like rotate 37 move 300 rotate 60 move 400 etc... Have you a way of measuring absolute rotation? or is it (...) (26 years ago, 7-Nov-98, to lugnet.robotics)

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