Analysis: Caterpillars and Snakes

The Cologne deployment highlights the need for true robot snakes that can work in wet environments and interior of mixed rubble. The ASC is actually a caterpillar. The important point is just like real caterpillars and snakes, the mechanical versions have different ecological niches- I want both. We’re missing a snake from our arsenal of ground robots. Never forget that the US&R ecological niche requires a self-cleaning camera (the equivalent eyelids and tears) to permit rescuers to see as dust, dirt, and water collect on the lens.

The dear ASC (which we’ve nicknamed “Catey”) provides the smallest size on a fieldable robot I’ve ever seen, on par with those big fat hairy caterpillars that either delighted or grossed you out as a child. Like a real caterpillar, it is slow and has to “go with the flow” as it can bend but can’t necessarily climb. Unlike a caterpillar, it is pretty stiff, as only the “head” can bend- the forward motion comes not from undulation but from vibration, which is extraordinarily brilliant but provides less propulsion. Think of the current ASC as a partially paralyzed caterpillar that can’t blink, as if it evolved in the desert- which is great for a fairly dry pancake collapse- like when we used it so successfully at the Berkman Plaza II collapse. I’d like to see the ASC adapt to become a rainforest caterpillar, able to blink and work in mud (the latter may be impossible due to clogging of the cilia). But don’t get me wrong, I’ll take the ASC caterpillar just the way she is!

Snakes, on the other are usually bigger than caterpillars, but more powerful and have eyes that blink. A lot of rattlers have simple thermal sensors for better targeting that poisonous bite (which could be transferred to finding survivors). A robot snake that slithered (technically traverse motion) could climb and more aggressively attempt to penetrate irregular rubble. Notice that snakes are smooth. Many mechanical snakes (see are tracked- lumpy and exposed. And big, just under the size of the Inuktun Extremes. Exposed segmented mechanical snakes (where the snake is a series of miniature tracks or wheels on articulated joints) collect mud and debris interfering with movement. And if there is a way for a device to jam or get tangled, it will. That’s why I am very excited about Howie Choset’s smooth, highly articulated snake (see ). He has been part of the CRASAR team since 2003 and it has been interesting watching his ideas about snakes for US&R evolve with each field exercise he and has students participate in. Anyway, what I want is the mechanical equivalent of a Texas brown snake, a snake that likes to burrow in moist compost (or a mixed rubble collapse).

CRASAR heading home

We’re in the airport now (painfully early in the morning at the Cologne airport, making our way home. The firemen found one of the victims early Sunday morning, the old fashioned way by slow, tedious extrication. As of this morning (Monday), it doesn’t look like the second victim has been found. We were not called out on Sunday but continue to learn more about robots that would be suitable for these conditions. It was a bit embarrassing, the Mayor, Deputy Mayor, and the Chief all shook our hands and were very enthusiastic, despite us doing nothing tangible. Indeed, we are very grateful because we learned so much.

The one photo that “got away” was that of a dozen women with cardboard boxes working in the light rain, picking up documents from the rubble a few meters from the rescuers carefully excavating for victims in the dangerous, unstablized rubble. The women looked like they about to weep from the lost and damage to the Archives, while the fire rescue workers were grim. A sad moment

Looking forward to sleeping on the plane!

Day 1.5 at Cologne

Quick notes before getting some sleep… we have been on standby since going to the site on Friday around noon. City of Cologne and fire department (still fuzzy on naming translations) have been terrific and the Fraunhofer Institute IAIS incredibly supportive.

The Archives buildings was a new, modern multistory commercial building surrounding by multistory residential buildings. When it collapsed into the hole, some of the surrounding buildings were damaged. The one where the two victims are missing is an older (like more than a 100 years old looking) brick building. When brick buildings collapse, the brick crumbles into sand and small pebbles, filling every possible void. Even the ASC couldn’t get in.

The robots were requested this afternoon for the mixed rubble from the houses and the Archives, but it wasn’t a good fit. There were small voids but we couldn’t stand at the face of the rubble due to safety reasons- and the ASC requires us to be right there. The voids big enough for the larger Extreme, which we could operate from the safe location ~10m away, were shallow and thus didn’t require a robot. More notes on how to build better robots.

We’re back on site tomorrow- a huge crane is being brought in to do more excavations and more voids may open. It looks like the old fashioned tedious manual rubble removal is the best technology for this job for now.

Lots of pictures but haven’t gotten permission to release them yet, here’s link to pics from the media and gratuitous coverage 😉

Local news in English: