Crawling McGregor

By jip @ Thu, 2008-06-26 17:57

Crawl around, line crawling

Actuators / output devices: An
Control method: autonomous
CPU: NXT brick
Operating system: leJOS firmware
Programming language: leJOS (java for lego mindstorms)
Sensors / input devices: NXT Ultrasound sensor, NXT motor encoders, NXT light sensors
Target environment: outdoor, indoor

This is just a strange thing that crawls around using its "arm". My ultimate goal is to add CMUCam3 and get the thing to follow some objects by crawling towards them. Locomotion is veeeery slow and suffers from bad traction of the arm. Initially I did use the claws that come with NXT kit as the end of the arm but they had zero traction so I decided to use the rubber wheel instead.

And yes, I do realize that in the title picture it looks like the robot has a serious hard-on :-D

By fritsl @ Thu, 2008-06-26 18:03

Way cool moves!!

By GobliZ @ Thu, 2008-06-26 18:53

Wouldn't it be better to

Wouldn't it be better to mount the crawling wheel sideways. That way it'll always crawl forward instead of getting stuck. I think. maybe you tried that already and it didn't work...

Cool robot. :)

Check out my robots - http://letsmakerobots.com/user/319/robots

By jip @ Thu, 2008-06-26 19:47

I'm not sure exactly what

I'm not sure exactly what you mean but I think that if I tell you, that the crawling wheel is in fact locked in place and can't rotate and thus have the most traction when it is mounted the way it is now due to the rubber, then I kind of answered your question... or maybe not? :-)

By jklug80 @ Thu, 2008-06-26 18:56

I was just wondering if Lego

I was just wondering if Lego could make those cables any longer ;) Seriously this is a fun looking robot. I love how every robot looks different. Even similar robots like YDM and YDM2 look different in a father son sort of way.

By BaseOverApex @ Thu, 2008-06-26 20:50

RCX Cables

I don't have NXT, but I always found my RCX cables to be too short. I ended up making my own. The Lego connectors came in two halves and inside it was possible to put an alternative cable. The cable spliced in when teh connector was closed.

By maneuver @ Thu, 2008-06-26 21:48

It sounds to me like the

It sounds to me like the front motor actually hits the ground before in the fully outstretched position. That can't be good for the plastic casing, I'd presume.

/ vzz-clck-"Maneuver"

By jip @ Fri, 2008-06-27 10:48

It's just the crawling wheel

It's just the crawling wheel hitting the table/ground, and anyway I think the motors can endure quite a lot of torture since they were designed to be used by (evil) kids :-)

By jip @ Fri, 2008-06-27 11:10

Oops

I just realized that it is in fact slamming the motor into the ground. Oh well... if it breaks it breaks :-).

By jgillick @ Thu, 2008-06-26 22:59

That is really cool

That is really cool looking! If you had 2 arms you could make it look like a person crawling. Could be a great prop for Halloween.

By jip @ Fri, 2008-06-27 10:50

Yes I will definitely look

Yes I will definitely look into making another arm. Since the NXT brick only supports 3 motors, I will need to make an I2C motor controller first I think - but that would probably be fun - in a way :-).

By Edtronic @ Thu, 2008-06-26 23:56

The cat is like HUH!

By GroG @ Fri, 2008-06-27 07:50

Great moves! Maybe a rachet

Great moves! Maybe a rachet on the rear wheels - that could keep it from slipping back when the arm is airborn. Or maybe a second arm! Excellent robot -

This migh be some inspiration - its one the size of a coke-can - you can throw it and it unfolds and starts crawling away

Damn, you cat is mellow ..

By jip @ Fri, 2008-06-27 10:38

Awesome link! Actually my

Awesome link! Actually my robot was inspired by a co-worker talking about doing a terminator-arm-robot :-).

Maybe I should look into that second arm idea... it would be kind of cool!

Maybe the robot should also say something like: "Sarah Connor, you will be terminated!"

By maneuver @ Fri, 2008-06-27 15:21

Sarah Connor, you will be terminated!

Good idea with the voice sample, except that it'd use alle your memory.

/ vzz-clck-"Maneuver"

By jip @ Fri, 2008-06-27 15:40

I think that with 256 KB

I think that with 256 KB flash memory and 64 KB ram there should be room enough to squeeze just a couple of 8-bit Arnold samples in there :-).