Acting as an ET, Robot Madeleine journeyed into the neural control space of four-flippered aquatic tetrapods to show us what swimming behavior looks like if you swim with two or four flippers. We compared benefits—speed and acceleration—and costs—power consumption. The differences in Madeleine’s swimming behavior and energy use indicate that a trade-off could exist between high cruising speed and rapid acceleration. If you want both, you are going to pay for it in terms of the food you need to eat to make the energy that your behavior requires. Although our curiosity is not completely satisfied, we haven’t gone mad—or have we?
It certainly took a kind of collective madness to build a self-propelled biorobot like Madeleine—madness, induced by a shared vision and then a bunch of people with the know-how, the time, and the money to get the job done.[165]
Robot Madeleine was custom built for Vassar’s Interdisciplinary Robotics Research Laboratory (IRRL) in about a year, from 2003 to 2004, by engineers at Nekton Research, LLC, in Durham, North Carolina. Working as Nekton’s vice president of Science and Technology was Chuck Pell, cofounder with Steve Wainwright of the BioDesign Studio at Duke University in 1990. Under Chuck and Steve, BioDesign Studio had produced the early prototypes of bioinspired devices that would lead to innovations like Nektors and Transphibians, a class of unmanned underwater vehicles of which Madeleine was the first.
Having created a toy chest full of commercializable ideas, in 1994 Steve and Chuck teamed with businessmen Gordon Caudle and Jeff Bourne to form Nekton Technologies Inc., an independent start-up company that became Nekton Research, LLC, in 2000. Nekton, which acquired multiple government contracts under the guidance of president and CEO Rick Vosburgh, was acquired by iRobot Incorporated in 2008. As a result, Madeleine’s four-flippered commercial descendants are now called iRobot Transphibians. Transphibians can be used for mine clearing, surveillance, and reconnaissance in physically challenging shallow and wave-swept marine environments.[166] You can see why Brett Hobson, Nekton’s first ocean engineer and one of the patent holders, calls the Transphibian “Madeleine on steroids.”[167]
Our shared vision for Madeleine began with Chuck sharing his vision. Before Nekton, during his time running the BioDesign Studio, Chuck drew a Kronosaurus on a napkin and started talking to me about building a life-size, swimming pliosaur. No big deal—a life-size and self-propelled pliosaur. As crazy as this sounds in the retelling, I didn’t think that Chuck was nuts, at least not because of that idea. You have to understand that by 1992 Chuck had already demonstrated that he could use a Nektor to propel a surfboard. I first saw him do this at the Duke Marine Laboratory. He sat on the board, legs out straight on the board, and then cranked a large metal lever back and forth between his legs. Because you couldn’t see the underwater Nektor attached to the shaft he was wiggling, his rapid exertions looked for all the world like he was trying furiously to tighten a bolt with a large socket wrench.
Always the enthusiastic, hands-on teacher, Chuck made all of us who were jeering him from shore give his swimming machine a try. Soon we were all hooked on flapping flexible foil propulsion, and we took turns wiggling the lever and zooming around the docks. The demonstration of Chuck’s crazy contraption was exactly the kind of thing that got the business-minded among us fired up. Gordon started thinking about building a company that would make quiet, low-speed trolling motors for bass fishing. Steve saw a science toy that could be used in the sink or bathtub to demonstrate how fish make waves of body bends in order to swim. In fact, this science toy, which Chuck dubbed “The Twiddlefish,” launched the toy company TwidCo, Inc., and Gordon and Jeff soon had little clown fish and sharks on the shelves of museum stores across the country.
But it wasn’t until Nekton was created in 1994 that Nektors were put to work propelling craft. Brett, renowned in the ocean engineering community for his work on high-performance submersibles like Deep Flight, was Nekton’s first employee. Arraying four Nektors around the circular belly of an ellipsoidal submersible, Brett and Eric Tytell built PilotFish, which quickly achieved the world record for underwater maneuverability, showing that Nektors had response rates twenty times faster than conventional thrusters, could provide thrust in any direction, and allowed PilotFish to use all available degrees of freedom.
By the time I approached Chuck about building a four-flippered robot in 2002, Nekton had left Nektors behind, according to Brett, leaving PilotFish on the shelf. Even though they were interested in exploring other body and flipper geometries, they didn’t have the funding. So we got it from the National Science Foundation in an equipment grant that I wrote with my colleagues at Vassar, Ken Livingston, Tom Ellman, Luke Hunsberger, and Bradley Richards.
Money in hand, we began the design of Madeleine in earnest. Chuck already had Maddie’s conceptual design drawn up when I came to work with the team at Nekton. Brett and Chuck were joined by engineers Robert Hughes, Ryan Moody, and physicist Mathieu Kemp. The Robot Madeleine project was important for the group because, said Brett, “[Madeleine] was the first piece of equipment that Nekton produced and delivered and somebody used.”
What made Maddie useful as an ET was not just her glorious Nektors but also the way in which the Nektors were programmed to operate. This programming was Mathieu’s masterstroke. Not only did he program the motor controllers, he also figured out how to have Maddie’s on-board computer interface with all the sensors I wanted. This gave Maddie all of the capacities that Nick Livingston, Joe Schumacher, and I needed to conduct our flipper experiments at Vassar. In addition, Mathieu programmed Maddie to be autonomous and employ a two-layer subsumption hierarchy in 2004. This was the first time, to our knowledge, that an autonomous underwater robot had used Rodney Brooks’s architecture (see Chapter 5). Although we never published Mathieu’s autonomous design, proof of Maddie operating autonomously can be seen on the Australian Broadcasting Company’s science and technology program, Beyond Tomorrow.[168]
In the same way that Chuck’s swimming contraption was a great catalyst for what might come from Nektor-based propulsion, Maddie turned out be a great spokesperson for Nekton and what they could accomplish. “Video of Madeleine performing,” reminisced Chuck, “electrified government sponsors who previously turned us away and who now said ‘yes’ to money for an even more powerful vehicle.” For demos to the Navy brass, Brett and Mathieu would borrow Maddie, give her special fins, reprogram her, and turn her into an amphibious surf-zone explorer (Figure 7.10). As a Transphibian, “[Maddie] was targeted for high-energy environments,” Chuck explained, “where bottom crawlers can deal with terrain and pelagic vehicles can’t deal with surge. So this tactically important zone had no vehicle that could thrive in it.” That’s no longer the case, thanks to the crawling and swimming Transphibian.
Robot Madeleine is not the world’s first and only Evolutionary Trekker. Josh de Leeuw, a former student who has spent time, as an employee, working with and rebuilding Maddie, pointed out that in 1997 Tony Prescott, professor of cognitive neuroscience at Sheffield University, built a wheeled, autonomous robot to test ideas about the locomotor behavior of Cambrian invertebrates. With the simple intelligence to detect a track that it had made, Prescott’s robot showed one possible neural mechanism that the ancient invertebrates may have used to create the foraging trails preserved as complex spiral patterns known as trace fossils.
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Robot Madeleine, like Tadro, has had multiple versions. Maddie 1.0 was self-propelled and controlled remotely by a human operator. Maddie 2.0 had all the on-board sensors, like the power monitor and the accelerometer, allowing her to collect data on herself. Maddie 2.0 was the version that I’ve talked about here and about which we’ve published our papers. Maddie 3.0 was programmed by Mathieu Kemp to be fully autonomous, employing a two-layer subsumption hierarchy (see Chapter 5) in which she selected a random depth and compass heading and then moved along that course until she either detected an object with her sonar or ran out of time (thirty seconds). Maddie 3.0 was destroyed, unfortunately, when we were filming her for the documentary
166
You can see Transphibians at the iRobot website: www.irobot.com/gi/maritime/Transphibian/.
167
B. W. Hobson, M. Kemp, R. Moody, C. A. Pell, and F. Vosburgh, “Amphibious Robot Devices and Related Methods,” US Patent 6,974,356, 2005.