Read aloud American researchers have developed a system for determining the position of submarines, which works on the basis of electrical voltages. In this way, the scientists mimic the navigation instrument of some freshwater and marine fish, which can orient themselves by their own weak electric field in their environment and recognize objects. The system called ElectroSenster consists of two electrodes that generate an electric field and two electrodes that can measure electrical voltages. The two pairs of electrodes attached the researchers around Malcom MacIver of Northwestern University in Chicago on the opposite sides of a rhombus, which is attached to a robotic arm. If the electric field is not disturbed, the readings of the sensors are the same. But once an object is near the electrodes, the field is disturbed and the measurements of the sensors give different results. Because the position of the object affects how the electric field is manipulated, a computer can use several consecutive measurements to determine the exact position of the object.
To test the facility, the scientists dipped the four sensors in a shallow water tank and moved them around a ball on the bottom of the vessel. The experiment was repeated in fresh and salt water and with spheres of different sizes and materials. In all experiments, after ten movements, the system was able to determine the position of the ball to within three millimeters.
The sensors scan the environment in all directions and can also detect extremely close obstacles. The method is therefore particularly suitable for small submarines that are used on the seabed or in very narrow passages and must be extremely manoeuvrable, the researchers said. The system is technically still far from being as mature as the natural sense of orientation of the fish.
New Scientist, online service ddp / science.de? Claudia Hilbert ad