14 Nov 2004 wildmage   » (Journeyer)

Robosphere 2004, Nov. 9-10 Eyewitness Account (Part 2)

I should mention that as a condition for being allowed to attend the Robosphere workshop for free, I was supposed to volunteer my time to help with the proceedings. I spent the early part of lunch getting briefed on my responsibilities. My job title for the first day was Miscellaneous. I was essentially supposed to sit near the entrance hall and take care of anything that didn't fall under the category of registration, audio/visual, or video recording. I think the only thing I did was to ask someone if they needed anything. They said "no".

So after briefing, I went to get some lunch. I think the first person I met was Greg Hornby. He was a former student of Jordan Pollack at Brandeis University and now working at NASA Ames research center. I didn't know this at the time, but I did ask him a little about his work. He mentioned that his work was on evolutionary algorithms. I wasn't particularly interested at the time because I've heard that word thrown about so often that I just considered it a dead-end buzzword. I came to appreciate it later in the workshop.

His work is essentially in evolutionary algorithms for computer-automated design. The way this works is that you give the computer a bunch of parameters, a task, and a simulation environment. The computer then proceeds to make up a robot design and test it in the simulation environment. If it does well, it tries to improve on that design. If it does poorly, it discards those changes and tries another route. What's interesting is that this is done in an analogous way to natural selection in the process of evolution. Many populations of different robots with different designs are tested in a simulation environment. The poor performers are terminated and the good performers are allowed to continue existing. In addition, the good performers are allowed to "mate" and create hybrid designs that try to combine the best features of both performers.

I think I talked more about this here in my Oct. 22 entry last year. This is a very interesting approach to robot design that is starting to show that it has more and more useful applications.

Someone else I met at lunch was Greg Chirikjian and one of his students, Kiju Lee, from John Hopkins University. His work involves self-replicating robots. I saw him once at a robotics conference in New Orleans, but didn't have a chance to talk to him.

The idea of self-replicating robots is that you send a small colony of robots to some place like the Moon or Mars. Once there, they utilize the resources that they find in the soil or regolith, synthesize this into parts, and make copies of themselves. This essentially allows the robots to multiply completely on their own and saves you lots of time and money in shipping extra robots and parts to these extra-terrestrial environments.

This may sound cool or scary, but it's a really really difficult problem. This idea has been around for quite a while, but not taken very seriously because the technology just isn't there. Chirikjian has shown several demonstrations of an actual self-replicating robot making a copy of itself in an autonomous manner. Albeit, the robot is made out of legos and there are only four parts to be assembled to make an extra robot copy. Nevertheless, the feat is amazing to anyone has actually tried to do something like this. Go ahead and try to do it yourself. You'll be surprised how hard it is to make a robot that can build and assemble an exact copy of itself-- even a simplified assembly.

After lunch, it was time to head back into the conference hall and assume my post as Miscellaneous man.

The first speaker was Ashley Stroupe from NASA JPL in Pasadena, California. She's one of the staffers on the Mars Rover projects, so she immediately has a superstar presence. Not that people are asking her for her autograph, but people are interested in her work like in the normal humdrum way of academics.

But this talk was not about the Mars rovers. This talk was about autonomous construction robots. More specifically, "Sustainable Cooperative Robotic Technologies for Human and Robotic Outpost Infrastructure Construction and Maintenance". Their work essentially consisted of two rover-like robots, with manipulator arms, and operating in a sandbox. There task was to go to two sides of a beam, pick up the beam in a synchronized manner, turn around and carry it to the construction site, and set the beam down aligned on top of another beam. This was done in a completely autonomous manner with no human intervention. This was the culmination of about 9 months worth of work.

I was deeply impressed. I've had experience trying to get mobile robots to interact and manipulate objects in precise way and realized all the difficulties. It's particularly difficult for mobile robots since you don't have a fixed reference frame to work with. The robot has to be adaptive and able to perceive the object well enough to know where it is and understand how it affects the object. Their only sensors in this feat were a camera and some force-torque sensors on the arms to keep the robots synchronized while carrying the beam. Some fiducial markers were placed on the beams and the cameras were used to detect them so the robots could more easily position themselves and the beams.

So currently the project at NASA is in very preliminary stages and its not clear whether it will continue to be funded, but this project seems to align very well with NASA's new space objectives outline by President Bush a year ago which include robotic and manned missions to the Moon and Mars.

More later.

Jacob Everist

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