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Subject: 
Shrimp Rover
Newsgroups: 
lugnet.technic, lugnet.robotics, lugnet.build
Date: 
Sat, 23 Mar 2002 20:33:19 GMT
Highlighted: 
(details)
Viewed: 
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Hello all,
  I've nearly completed my shrimp rover implementation. Development is on
pause being I’ve completely run out of short Lego wires. I’m not sure if I
will ever go any further with this, I’ve got a lot of ideas that I want to
build, so I may end up taking it apart.

I’ve posted some pictures on brickshelf:
http://www.brickshelf.com/cgi-bin/gallery.cgi?f=14018

Shrimp Features
---------------

- Dual RCX. The RCX mounted higher up, and more visible, controls rotation
and wheel power to the front and back wheels. It is responsible for keeping
the front and rear wheels in sync when turning. This RCX will have a
micro-motor and technic switches that will multiplex the power between the
drive and turn motor banks. (This isn’t shown because I don’t have enough
wires). RCX 2, which is mounted underneath the first RCX and between the 2
sets of boggied wheels, controls the power for the 4 central wheels.

- 10 Motors (an 11th micro-motor will be added for motor multiplexing). Each
drive motor is geared with a worm gear, giving it the strength it needs and
preventing slippage when climbing. The micro-motors are also geared down
with a worm gear.

- Studless design, at the moment there are only a few visible studs, final
design will be 100% stud-free. Most of the structure is comprised of
liftarms, with relatively few bricks, less then 50 actually.

- The rover has the ability to turn. Front and rear wheels are mounted with
turntables and dual micro-motors. Rotation sensors are located between the
micro-motors for precise wheel placement when turning.  Turning requires all
6 drive motors to be shut off. The 4 micro-motors located front and back are
turned to rotate their respective wheels.  The 4 micro motors are switched
off and the 6 drive wheels turned back on. The rover will then begin driving
forward while turning.  It is very easy for the wheels to tear apart the
structure of the rover if the wheels where not aligned correctly.

The rover can theoretically climb obstacles of around 2x to 2.5x the wheel
diameter. Currently the rover has difficulty climbing anything greater then
the wheel diameter. The problem occurs when, for example, the front wheel is
climbing an object, and the remaining 5 wheels are pushing forward, causing
a lot of stress in the climbing wheel. Mounting sensors on some or all the
wheels can solve this problem. When the sensor is depressed, then the other
wheels shut off allowing the wheel to climb.

-Brian



Message has 2 Replies:
  Re: Shrimp Rover
 
I had the pleasure of seeing this in person. Brian has a keen eye for Mechanical Engineering. The syle in which you build compliments the creations you come up with. The techniques used are top notch. Excellent write up on the features and functions (...) (22 years ago, 23-Mar-02, to lugnet.technic, lugnet.robotics, lugnet.build)
  Re: Shrimp Rover
 
If your going to build such cool projects, you should order some more wires from Lego Dacta. Great job! -- Bob Fay THE SHOP (URL) Sadowski" <twodijits@hotmail.com> wrote in message news:GtG13J.K42@lugnet.com... (...) keeping (...) Each (...) and (...) (22 years ago, 24-Mar-02, to lugnet.technic, lugnet.robotics, lugnet.build)

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