Gyroscope
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A gyroscopic instrument, also called a gyrostabilizer or gyroscope (Greek γύρος gyros, German 'rotation' and σκοπεῖν skopein 'to see'), is a rapidly rotating, symmetrical gyroscope that spins in a movable bearing. The bearing may be a gimbal or a frame in the form of a cage (see figure). Due to the conservation of angular momentum, the gyroscope has a high inertia to changes in position in space. If the rotational speed between the gyroscope and the cage is measured, it is called a gyrometer. Gyroscopes are used as navigation instruments and for active attitude control, especially in aerospace. For the attitude control of spacecraft such as satellites, it is exploited that the overall system of spacecraft and gyroscope retains its angular momentum and thus the attitude can be controlled by angular momentum transfer between the two.
Currently, the term gyro or gyro is used figuratively to refer to a variety of rate-of-rotation sensors that do not include gyroscopes but serve the same purpose as an actual gyro instrument.
Simple gyroscope
History
The gyroscope - today the terms gyroscope and gyrocompass are used synonymously - was invented in 1810 by Professor of Physics, Mathematics and Astronomy Johann Gottlieb Friedrich von Bohnenberger at the University of Tübingen; a specimen was first rediscovered in 2004 by Alfons Renz, a private lecturer at the Faculty of Biology at Eberhard Karls University Tübingen, at the Kepler Gymnasium in Tübingen. In 1852, Léon Foucault further developed the gyroscope to the design and manufacture of the gyrocompass. The first gyroscope of 1810 is indistinguishable as an idea and was the essential basis for the invention of the gyrocompass in 1852.
Physical principles
A gyroscopic system can be regarded as a closed system whose angular momentum remains constant. If an external force tries to tilt the axis of rotation of the gyroscope, a torque perpendicular to the force results, which the angular momentum tries to match according to the rule of parallelism in the same direction. The angular momentum tilts perpendicular to the applied force. The axis of rotation is coupled to the angular momentum via the inertia tensor, which is why the axis of the gyro follows the angular momentum and thereby orbits it on a narrow cone, see spin stabilization. The effect is known, among other things, from the toy spinning top, whose axis precesses along a cone shell due to the gravity that wants to tilt it. The opening angle of the cone in a symmetrical gyroscope is inversely proportional to the square of the rotational speed and the ratio of the axial to the equatorial main moment of inertia of the gyroscope.
