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Subject: 
Re: How much weight can a LEGO chassis carry around?
Newsgroups: 
lugnet.robotics
Date: 
Sat, 10 Dec 2005 18:25:14 GMT
Viewed: 
1300 times
  
If they can build bridges that can take a few something like 28-30
kilos of weight, then handling a laptop is not impossible. It would
really be a matter of doubling up load-bearing beams and supporting
them with the right structure, being aware of weak points, and where a
beam may bend or break. It is about making sure that there are
multiple supports so that one pin is not left bearing it and gets
sheared off. I really dont doubt that Lego can do this, but it is
really a matter of the engineering. You might have to build it larger
than you wanted, but it is doable.

You might really have to do your home work on load bearing structures,
bridges, lattices and techniques to take the force away from
troublesome hotspots. I look forward to seeing it. I have been
considering building a Lego bot chassis around an SBC for a while, but
not entirely sure what to do with the power supply yet.
--
Danny Staple MBCS
OrionRobots
http://orionrobots.co.uk
(Full contact details available through website)


On 10/12/05, Mr S <lego-robotics@crynwr.com> wrote:
Dan,
I remember seeing this robot. I didn't remember that
you built it, but its impressive.

OT Comment: Can't use $ony products anymore though

I think you underestimate the ability of Lego for
strength. Construction techniques make it possible to
build quite sturdy Lego robots. You do need to be
mindful of the mechanics of structural stresses, but I
think every Lego builder is to some extent or another.

I wish I was not going to be so busy for the next 2
months, but the once per year visit with in-laws and a
day or 5 on the piste is just mandatory to put at the
top of the to-do list this time of year.

One of my projects for next year though is going to be
a Lego robot that can carry a dead weight laptop. Just
to say it can or cannot be done with a regular sized
average type laptop. I'll try to set the record for
load bearing capacity in a Lego robot :) Of course,
anyone is invited to beat me to it as well.

Cheers


--- dan miller <danbmil99@yahoo.com> wrote:

Apologies if this double-posts, Yahoo is in a mood.

I solved your problem by purchasing the lightest
laptop I could find, a Sony
ultralight (PGC 161L, $800 on ebay).  It's a hair
over 2 lbs, and I've used
it on a couple projects:

http://www.danbmil.com/lego/

It has a built-in camera, which is very cool.  The
last 'bot in these pix
could locate a bottle (with a pattern of stripes
taped on it), go to it,
pick up the bottle and bring it back to me (sort
of..)  It was definitely
pushing the limit on Lego load-bearing capacity.
Note the omniwheel casters
from Charmed Labs.  (the laptop sat right behind the
RCX's, with the top
flipped up and the camera, which is on this little
swivel, pointing
forward).

As for doing it with a regular-sized laptop (6-8
lbs), I think your best bet
would be the trailer, but it just might be too big.
Two sets of double
wheels each, right near the center of gravity, with
a caster cantilevered
out (so it doesn't bear much weight) could do the
trick.  Or pick up the
Omniwheels, they're pretty cool.

-dbm


ps I recently started a platform that uses three
Lacrosse balls in little
cages as the wheels.  Will post when I get around to
it.


--- steve <sjbaker1@airmail.net> wrote:

Joe Strout wrote:
In lugnet.robotics, Nathan Colyer • <ncoly1@eq.edu.au> wrote:

It might work to make a robot that tows the • laptop on a trailer setup?

I don't see how that solves any problems.

Ah, sort of the 18-wheeler approach to carrying • heavy loads.  That's not
a bad
idea; certainly it solves the axle-support and • skid-steering problems.

How?  The trailer still has to have a bunch of • axles in order to spread
the weight - and when you do that, the trailer is • (in effect)
skid-steering.

But it
makes the steering code a much harder problem, • doesn't it?  I can
imagine my
poor bot getting stuck in a dead-end hallway, • having a hard time turning
itself
around.

That's the cool thing about using a synchro • platform - the robot can
drive in any direction it wants without turning • around (in fact, it
*can't* turn around).  But it is the ultimate in • manouverability.



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Message has 2 Replies:
  Re: How much weight can a LEGO chassis carry around?
 
I built a laptop roving wireless web controlled robot 4 or 5 years ago. Check it out at: (URL) (19 years ago, 11-Dec-05, to lugnet.robotics)
  Re: Heavy load on LEGO chassis over uneven ground
 
(...) Another thing to consider when carrying so much weight is the gear ratio and motor power required. An under-powered robot with excess shaft friction will not drive in a straight line! I built a strong robot chassis a few years ago using 12V (...) (19 years ago, 11-Dec-05, to lugnet.robotics)

Message is in Reply To:
  Re: How much weight can a LEGO chassis carry around?
 
Dan, I remember seeing this robot. I didn't remember that you built it, but its impressive. OT Comment: Can't use $ony products anymore though I think you underestimate the ability of Lego for strength. Construction techniques make it possible to (...) (19 years ago, 10-Dec-05, to lugnet.robotics)

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