Robots- a new vision

A study has used rodent-like robots to look at the evolutionary development of different mating strategies over an extended period of time. In contrast to direct studies of nature, the observation of robots allows researchers to avoid inherent time-based difficulties of studying evolution, with the results suggesting something a little more complex than the classic one-beats-all natural selection hypothesis.

According to conventional evolutionary theory, a single, optimal phenotype, or mating behavior, should predominate all others, with natural selection taking care of the less efficient strategies. However, in nature we witness a great many populations where this is not the case, and instead see a variety of successful behaviors co-existing. Due to our short life spans, developing an informed theory on why this is the case is decidedly problematic when looking directly at long-term evolutionary cycles in nature.

The study, conducted by Dr. Stefan Elfwing of the Okinawa Institute of Science and Technology, was designed to tackle this long-standing problem of evolutionary theory through the use of robots. Known as Cyber Rodents, the wheeled robots were equipped with cameras for visual detection of energy sources (colored blue) and the rail lamps of other robots (colored green), and infrared communicators for the exchange of genotypes. In biological terms, the Cyber Rodents were hermaphrodites, with all robots in the test able to produce virtual offspring.

During their 288-second life spans, the robots were able to execute two basic tasks – searching for a partner with which to mate, or searching for batteries. The probability of successfully producing offspring was determined by the robot’s internal energy level, thus creating a trade-off between foraging for energy and moving directly to mate.

Dr. Elfwing was able to avoid the inherent time frame difficulties associated with observing evolution in nature, using computer simulation to study over 1,000 generations in each experiment. The results detail the emergence of two distinct behaviors, or phenotypes, within the experiment – the Forager and the Tracker.

The Forager phenotype would actively search for batteries, only mating when it saw the face of another Cyber Rodent, and never waiting for them to turn around. Conversely, the Tracker would wait for other robots to turn around for mating, with the length of time waited being determined by its current internal energy level.

The experiment was conducted some 70 times with varying results, but it was the experiments where more than one phenotype emerged that successful reproduction rates tended to be highest.

By conducting the experiment with different ratios of phenotypes, Stefan was able to show that the two behavior types could efficiently co-exist within a single population, with the stable ratio being 25 percent Foragers to 75 percent Trackers.

"In this experiment, our robots were hermaphrodites, all robots mate and can produce offspring," said Dr. Elfwing. "In the next stage, we want to see if the robots will take on male and female roles, by taking different risks and costs in reproduction.”

Although modern jet airliners may be at the cutting edge of technology, assembling them is, in many ways, still as much of a craft as 18th century shipbuilding, requiring loads of skill and manual labor to get the job done. The Fraunhofer Institute for Machine Tools and Forming Technology (IWU) in Chemnitz, Germany wants to bring airplane construction into the 21st century with a snake-like robot that can assemble airplane wings by reaching into narrow, hard to reach cavities.

Airplane manufacturer Airbus expects to see air traffic triple by 2030, with major airports handling close to half a million passengers a day and Fraunhofer says that current aircraft construction methods will have difficulty keeping up with the demand for new planes. One answer is to automate assembly, but wings pose some tricky problems that most industrial robots can’t handle because they’re too inflexible and their reach is too short to extend the up to five meters (16 ft) required inside the wings.

Modern wings aren't just metal planks sticking out of a fuselage. They’re a complex collection of fuel tanks, hydraulics, power cables, engine supports, ailerons, flaps, ribs, struts, spars, and stringers. This results in all manner of small, hollow chambers that workers need to get into to drill holes, attach bolts, and seal joints.

Needless to say, it’s extremely slow, hard work that has to be done in the presence of solvent fumes. Look in a modern airplane assembly or maintenance manual and you’ll find detailed instructions for workers on how to wiggle into a crawl space and reach a widget. As a result, major airliner manufacturers are leading employers of little people, who are hired to work in confined spaces, such as wings.

The Fraunhofer approach was to come up with a 60 kg (132 lb) robot with an arm that resembles an automated snake. It’s built in eight articulated sections with a total length of 2.5 m (8.2 ft), weight of 15 kg (33 lb), and ending in a hand or inspection camera. According to Fraunhofer, the key to the snake-like robot is a patented gear system with motors generating 500 Nm of torque integrated into each of the arm’s eight sections. These, combined with a cord-and-spindle drive system, allow each section to turn independently up to 90 degrees.

"The robot is equipped with articulated arms consisting of eight series-connected elements which allow them to be rotated or inclined within a very narrow radius in order to reach the furthest extremities of the wingbox cavities," says IWU project manager Marco Breitfeld. "That’s why we often refer to the system as a snake robot.”

Currently, the robot is undergoing mechanical design and testing and will be displayed at the Automatica trade show in Munich from June 3 to 6. The next stage in the project involves installing the robot on a mobile platform or rails, allowing it to travel along the length of the wing while working. Fraunhofer says that a full-scale version of the robot should be ready by the end of the year.