Back in 2007 and 2008, funding agencies had a pretty hefty interest in robots with amoeba-like locomotion, also known as whole-skin locomotion (WSL), blob 'bots, or Chembots. NSF awarded $400k to Dr. Dennis Hong of Virginia Tech's RoMeLa Lab and DARPA awarded $3.3M to iRobot to develop such robots. Now, most people are familiar with iRobot's jamming skin robot announced at IROS 2009 (photos / videos below). However, I would like to share with you the equally-clever and interesting work of Dr. Hong, including a new whole-skin locomotion robot called ChIMERA: "Chemically Induced Motion Everting Robotic Amoeba" that was unveiled at a recent TEDxNASA event. Dr. Hong's robots resemble those slippery water-snake toys that are incredibly difficult to grasp, with silicone skin (flexible but rugged exterior) and water or gel inside (soft interior). Read on to learn more!
Here is a 30-second excerpt of Dr. Dennis Hong's TEDxNASA talk where he explains the RoMeLa Lab's whole-skin locomotion robots. The whole (18+ minute) talk is embedded at the bottom of this article. I recommend watching it if you have time -- it's worth every minute.
Update 2/10/2010: At the request of TEDxNASA, the reduced length video has been removed. The salient portion of the full-length video (below) begins at 7:27.
Unfortunately, the interesting chemistry involved in ChIMERA's chemical actuation is still in stealth mode (hopefully a paper forthcoming). However, early work on ChIMERA is clearly documented in a nice Masters thesis by Mark Ingram, along with his feasibility experiments shown in the video embedded below.
I'm particularly fascinated by the robot's fast movements (0.5 m/s) and ability to squeeze through small holes (half its own diameter). It certainly piques my imagination.
The fact that so much of this early work is based off of slippery water-snake toys, the same ones that I played with as a child and that can be purchased for less than $2 (pictured below-left), certainly speaks to Dr. Hong's ingenuity. They have certainly made some impressive progress between these new robots and their two-year-old band-driven prototypes (pictured below-right).
Naturally, one of the largest challenges is actuating the outer ectoplasm. So far, we have seen large rotating bands (super-early prototype above), pre-tensioned skin, cable squeezed, and chemical actuation. The chemical method is compelling because of biological parallels, though I can imagine myriad hurdles in transporting and applying the "fuel." My favorite method proposed is to use electroactive polymers (below left) as the skin to provide the compressive pressure at the uroid or expansive pressure at the hyaline cap. It seems they have also proposed using air-driven tubes (below center and right) to provide the necessary pressure.
Of course, it is also prudent to examine iRobot's "Blob 'Bot" that used jamming skin (presented while at IROS 2009) to achieve similar amoeba-like objectives.
During military operations it can be important to gain covert access to denied or hostile space. Unmanned platforms such as mechanical robots are of limited effectiveness if the only available points of entry are small openings.
The goal of the Chemical Robots (ChemBots) Program is to create a new class of soft, flexible, mesoscale mobile objects that can identify and maneuver through openings smaller than their dimensions and perform various tasks.
The program seeks to develop a ChemBot that can perform several operations in sequence:
- Travel a distance
- Traverse an arbitrary-shaped opening much smaller than the largest characteristic dimension of the robot itself
- Reconstitute its size, shape, and functionality after traversing the opening;
- Travel a distance
- Perform a function or task using an embedded payload.
This program creates a convergence between materials chemistry and robotics through the application of any one of a number of approaches, including gel-solid phase transitions, electro- and magneto-rheological materials, geometric transitions, and reversible chemical and/or particle association and dissociation.
With ChemBots, our warfighters can gain access to denied spaces and perform tasks safely, covertly, and efficiently.
As promised, here is the entirety of Dr. Dennis Hong's TEDxNASA talk: