Robot + Lego = Pretty Cool

X-Brat

This is a pretty cool robot. I have thought about building a bot that shoots, but haven’t really figured out a good way of locating the target. Shooting at a light source or something might work.

The best part is the builder get shot at by his own creation.

Escapements

Some years ago, I worked several times (mostly unsuccessfully) to build a pendulum clock. I had no problems with the hand movements, the gearing, the weights, the pendulum, the structure; I had it all figured out. But I had lots of problems working out the escapement. An escapement is a device which converts continuous rotational motion into an oscillating or back and forth motion. This creates the familiar tick tock sound.

Very generally speaking, the pendulum, the weight and the escapement work together to create the power of the clock. The weight pulls on a drum which turns the escapement wheel. The escapement wheel transfers very small impulses of force to the pendulum to keep it swinging. The pendulum will always swing at a constant pace or period, thus a pendulum is a great way to keep accurate time.

The tricky part is creating an escapement that will work regularly, have enough power to keep the pendulum swinging, and not too much so the pendulum is over powered and swings wildly. YouTube user BenVanDeWaal seems to have this problem licked. It seems he has devoted his entire Lego building existence to building escapements, and I might say he has done a very nice job.  He has several videos of several escapement types, but here are a few of my favs:


 

 

 
There are many more, and if you like these, go visit BenVanDeWaal's site.

Short Dry Spell On Posts

Sorry about the short dry spell on posts.  We are dealing with the flu bug all around us, plus I am preparing for an interview for a really great job.

But here is a neat video of some non-robotic kinetic sculptures.

Be back soon!

Friday's Idea-Omnibot

Omnibot was every boys dream in the mid 1980’s. If you had one, then you also had a complement of jealous friends, me included. Just another example of how 25 years takes away the feeling of “I have to have one” and replaces it with the feeling “I don’t want that junk, I have something much better.”




Building this out of Lego would be pretty cool, and the best part is that we could make it with many, many more functions.

Mechanisms and Linkages

As I have mentioned over and over, I am a fascinated by motion and movement. I have posted a few kinetic art videos of which I am a huge fan, and there will be more. A few of my favorite classes in college were Kinematics, which is “the branch of classical mechanics that describes the motion of objects without consideration of the causes leading to the motion,” Dynamics, which is “the mathematical analysis of the motion of bodies as a result of impressed forces,” and the course that applies the two in real world applications, Kinematics and Dynamics of Machinery.

Much of the applied course was devoted to linkages and mechanisms. There are several classes of linkages and probably hundreds of named linkage arrangements. I own several books which verbally and mathematically describe many of the linkages. I get a kick out of looking at a machine and finding a linkage or mechanism that I recognize.

But I have a feeling that many of the linkages and mechanisms will be replaced by more mechanically simple servo motors and linear actuators. If you look at old machinery, you will find all kinds of cool movements generated by cams, levers, mechanisms and linkages, but with robotics and complex mathematics, some of those devices are obsolete. But they will never go away, and even more complicated linkages are being developed which I really like.

You can find tons of videos of many of linkages on YouTube.com and similar sites. One of my favorites is of course Theo Jansen’s Strandbeest.

The Strandbeest has been duplicated in several mediums including Lego. I’m not going to link to any of those videos out of respect for the artist, but some of those are quite impressive as well.  If you are not familiar with Jansen and the Strandbeest, I highly recommend visiting the link.

I have found several really interesting pages devoted to sharing linkage and mechanism designs and graphics. Here are a few;

RoyMech. This is a detailed page including all kinds of engineering resources, but my favorite is Mechanisms.

KMODDL. “KMODDL is a collection of mechanical models and related resources for teaching the principles of kinematics--the geometry of pure motion. The core of KMODDL is the Reuleaux Collection of Mechanisms and Machines, an important collection of 19th-century machine elements held by Cornell's Sibley School of Mechanical and Aerospace Engineering.”

Brock Institute for Advanced Studies. This page shows animated graphics for several linkages.

Kanagawa Prefecture’s Linkage mechanism simulator is a downloadable linkage simulator.

Roomba Pac-man

The Roomba is a robotic household vacuum cleaner. It’s a favorite hacking target of some people and you can find several blogs and videos around the net. Most of them are pretty lame compared to even a basic obstacle avoidance NXT robot. But this one is pretty cool and very complicated.



It would be way over my head to program, but nonetheless, fun to think about building with a full set of NXTs.