Biped robot competition?

You've heard of the Trinity College Firefighting Robot Competition
(http://www.trincoll.edu/events/robot )? There is a biped division for
the contest. That would be fun I bet!

Randy Hootman - President
Modoro - Linux/Java Robots
http://www.modoro.com

marek@tynska.cuni.cz wrote:

Dear Randy,

thank you for this suggestion, it looks very well, their photogallery
impressed me. But I think I am out of their size specification -- my
robot is too high when standing (about 50cm). What a pity... (but, they
write "to fit in the box" -- ok, he can fit, if knee joints
appropriately turned).

Best regards,
Marek P.

    --The thing that comes to mind re: walkers were the
competitions the Brits put on called the Techno Games. Carried briefly
on US TV; not sure if it's still going on or not, but there were a
couple of very kewl walkers developed there. One biped wound up getting
made into a kit that Parallax sells. 'Course nowadays the "state of the
art" for kits are the Japanese and Korean kits that sell for around
$1,600 apiece (yeowch!!). OTOH if you can getcher hands on a couple of
R/C servos and find some of the softwar these beasties are running you
can do the same thing very quickly and very cheaply. I saw one made of
..get this: popsicle sticks! Not only could it walk, the thing could do
a sort of forward roll, then get up off the ground and keep walking.
Will see if I can find some links for this.

--
        "Steamboat Ed" Haas         :  Whatever happened    
        Hacking the Trailing Edge!  :  to Tom Nelson?
                   http://www.nmpproducts.com/intro.htm
                   ---Decks a-wash in a sea of words---

The problem with walkers, as I see it, is that you need a *lot* of
torque to move the payload. And the power requirements go up for
larger payloads. The Japanse Robo-One bots are cool, but they seem
to be fancy remote controlled toys. They don't have the payload
or endurance to use a powerful CPU for autonomous action.

I'm starting to design and build a medium-sized robot (it should
stand three to four feet tall when it's done). This robot will
have three legs, mainly because I have always wanted a build
a tripod.

The problem is that the more powerful RC servos use a *lot*
more power. I'm still going to try it with 1/4 sized servos
and the Hitech robotics servos. It should be an adventure.
--
D. Jay Newman
http://enerd.ws/robots/

I believe that that is a wrong assumption. If walking would take so much
energy, why can humans hike for hours, but fail to hold out their arm
for five minutes. Obviously, walking takes less energy than holding out
one's arm!

It does take a lot of energy and toque to get up from the ground,
especially in the knees, but once you are standing up and you have a
good walk cycle, bipeds hardly use any energy. It is essential though to
have a correct joint order and position. Robo-one's are definitely too
simple for efficient walk cycles.

My biped is 40cm and uses 4 Amps when getting up from the ground, but
less than an amp to walk. With 2400Ah NiCads, it can walk for over two
hours. And that's not even NiMh yet... .

Matthias

bad example...  Holding out your arm uses muscles that aren't normally
used, and tire easily due to them being weak actuators...

you can move 5 pounds with a small solenoid, but hold it there for a
long time
and the solenoid overheats and burns the coil.  Same thing with your
arm,
but your brain is hopefully smart enough to put your arm down before
you
start damaging muscle/tendon, etc....

Better example:

human can walk for hours, but not jump rope..

walking requires little energy, because you are using weight
distribution/
balance to move forward.  Lift your leg (only lifting the weight of
your leg),
move it forward, lean forward.  Your body falls towards your forward
leg,
and you move forward.

Jump rope:  each time you jump, you are lifting weight of entire body.
No balance involved, no falling with the assistance of gravity to help
you.

    --Well for bipedal and powerful take a look at what's been happening
with the Tetsujin competition. Admittedly these aren't autonomous systems,
but they're only one step away, so to speak. IIRC the current weight lifting
record is over 400 lbs, heh. Deets at the Servo magazine website; I think
they started the competition.

--
        "Steamboat Ed" Haas         :  Whatever happened    
        Hacking the Trailing Edge!  :  to Tom Nelson?
                   http://www.nmpproducts.com/intro.htm
                   ---Decks a-wash in a sea of words---