Tag Archives: DARPA
The Luke Arm
In 2005, the U.S. Defense Advanced Research Projects Agency (DARPA) sought out the greatest inventor in the country. Too many soldiers were coming home from Iraq with missing limbs, and DARPA was determined to give them the best treatment and technology available. They approached prolific inventor, Dean Kamen, and gave him the challenge of building a lightweight prosthetic arm within 2 years that would have enough dexterity to allow the wearer to pick up and a grape without damaging it. Kamen was initially deterred by the ambitious timetable, but eventually decided it had to be done. At his DEKA Research labs, Kamen and his team developed what they called the “Luke Arm” within 18 months. The device is named after Luke Skywalker who, after losing a duel with Darth Vader in “The Empire Strikes Back”, was given a prosthetic arm that appeared so tightly integrated with his real body that he could trivially operate his new hand just as he did before.
Tight integration means there must be many ways for the user to easily send commands to the prosthesis so that it becomes a natural extension of their body. The Luke Arm can be controlled by nerves, muscles, and foot pedals. A new user can comfortably control the artificial limb after just 10 hours of practice. The arm, loaded with processors, also has haptic feedback. Pressure sensors on the fingers send signals back in the form of vibrations, so the wearer can tell how hard they are grasping an object (a requirement for passing DARPA’s “grape test”). So far, DARPA has invested over $70m in the venture. The arm will be commercialized once the FDA conducts clinical trials and grants approval.
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Robo-lobster
Joseph Ayers has a thing for lobsters. He likes to cook them, eat them, and build them. In his book, “Dr. Ayers Cooks With Cognac” he describes several creative lobster recipes from Cajun to Mediterranean and everything in between. His favorite way to eat a lobster is simply dipping the meat in butter accompanied with a glass of chardonnay. And, when it comes to building robot lobsters, he prefers the kind that can wander the sea floor searching for mines.
A biologist and neuroscientist, Dr. Ayers developed his robo-lobster at Northeastern University between 1999 and 2002 with funding from the Office of Naval Research (ONR) and the Defense Advanced Research Projects Agency (DARPA). Working from Northeastern’s Marine Science Center at East Point in Nahant, Massachusetts, Ayers looked to real-life lobsters for inspiration. He notes that lobsters are at the top of the food chain in their environment and so have a good built-in seek-and-destroy mechanism.
His robots are controlled with artificial neural networks, which are used to make subtle decisions such as whether to walk over or around a rock. When it comes to tweaking the design, Ayers always went back to the original, studying the behavior of living lobsters, trying to replicate their behavior. The plastic antennas sense obstacles, the eight legs can propel it in any direction, and the claws and tail keep it stable in turbulent water.
The robo-lobster’s actuators are controlled by Nitinol, otherwise known as “muscle wire”. Nitinol can change shape when a current is passed through it, making it more life-like and less “robotic”. Also, Ayers’ neural networks use Central Pattern Generators (CPGs), specialized neural circuits found in all animal brains that automatically generate a rhythmic patterns. The CPG acts as the source for the robots pattern of locomotion.
The robo-lobster is an excellent example of biomimicry, where ideas from nature are incorporated into robotic designs, however, a practical mission for the robo-lobster has yet to be demonstrated. In addition to finding mines, Ayers notes that it might also be used to measure pollution levels on the ocean floor. The robo-lobster was put on display at the Cooper-Hewitt museum in New York in 2007 as part of its “Design Life Now” exhibit. It was also named one of the Coolest Inventions of 2003 by Time Magazine.
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Robots That Balance
Have you ever tried to balance a broom on one finger? Humans can do this fairly easily, and so can machines because the control system equations for this “inverted pendulum” system are relatively simple. It turns out that the process of walking and running in animals and robots is very similar to balancing a broom. If you assume the body of the robot is always about to fall over, then the inverted pendulum equations can be used to compute where the legs should be at each moment in order to maintain balance.
Marc Raibert, who founded the MIT Leg Laboratory in the 1980s, used this idea to build a robot with a single leg that could maintain its balance. Although it looked like a hyperactive pogo stick, the “hopper” robot was a success. Expanding on this work, he later moved to two legs, and finally four:
In 2005, Raibert founded Boston Dynamics, makers of the Big Dog military pack robot which uses the same basic concepts for remaining dynamically balanced. In fact, it can stay balanced on slippery surfaces and even remain stable after receiving a sharp kick. Boston Dynamics is funded by DARPA. The pack bots are designed to assist soldiers by following them in the field and can carry up to 120 pounds of supplies across a variety of terrains.
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Evolved Virtual Creatures
The Connection Machine was a supercomputer designed by Daniel Hillis who came out of the MIT Artificial Intelligence lab in the early 80′s and started Thinking Machines Corp in Cambridge, Massachusetts. The Connection Machine used a unique parallel computer design with over 64,000 small processors all linked together, following a more brain-like architecture (plus it had lots of cool blinking red lights on the front). The ingenuity of the computer design attracted the attention of DARPA from which Thinking Machines received significant funding.
Karl Sims was an artistic consultant whose job was to come up with ways to show off the Connection Machine. One of his projects was a simulation of Darwinian evolution that produced designs of “virtual creatures” in a 3D environment. The simulation required a massive amount of computational power, and the lifelike forms that emerged made for a compelling demonstration of Thinking Machine’s latest model, the CM-5.
Despite the inherent awesomeness of the CM-5, no market could be found for the computers and with increasing competition from more established manufacturers, Thinking Machines filed for Chapter 11 bankruptcy in August 1994. Later, Sun Microsystems and Oracle bought up the remains. And, while the Connection Machine has since been relegated to the dark recesses of the National Cryptologic Museum, Karl Sims’ experiment still represents one of the best examples of the creative power of artificial evolution to date.
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