Since the angular momentum H of the gyroscope is very large, the precession period
Upon deviation of the axis Oz of the gyroscope from the vertical Oζ, the axis Oz starts to precess about Oζ under the influence of the force of gravity P, circumscribing a cone whose vertex is at point O. This type of vertical gyroscope is used in the automatic stabilization systems of various moving objects, in roll stabilizers for ships, and for the stabilization of aircraft, as well as for determining the curvature of boreholes and mine shafts.Īnother type of vertical gyroscope, which does not require a correction system, is the gyropendulum-a gyroscope with three degrees of freedom, whose center of gravity G is located on the rotor axis at some distance l from the support point O (Figure 2). Vertical pendulous gyroscopes are used for determining the roll and pitch angles of ships and the bank and pitch angles of aircraft. Schematic diagram of a vertical pendulous gyroscope: (1) rotor, (2) and (3) inner and outer gimbal rings, (4) and (5) correcting pendulums, (6) and (7) moment transducers, (8) and (9) potentiometers In precision vertical gyroscopes, corrections for the earth’s rotation and for the object’s own motion are introduced to increase accuracy.įigure 1. The error of vertical gyroscopes of this type, which is determined by the deviation of the axis from the vertical of the locus, may vary from a fraction of a degree to minutes of arc. The potentiometers are used to determine the angles of inclination of the object with respect to the plane of the horizon.
Various correction systems are used for maintaining the axis of an astatic gyroscope in a vertical position for long periods of time.Ī vertical pendulous gyroscope (Figure 1) is a free astatic gyroscope in which the correction system consists of the pendulum correctors, which record the angles of deviation of the gyroscope’s axis from the vertical of the locus, and the moment transducers, which apply to the gyroscope the corresponding correcting moments, causing the precession of the gyroscope’s axis toward the vertical of the locus. Instruments of this type, called artificial horizons and roll stabilizers, are used in ballistic missiles for determining their deviation with respect to the vertical and horizontal planes (angles of pitch, yaw, and bank). Therefore, without corrective devices, such an instrument may serve only as a short-term indicator of direction (particularly of the vertical). With respect to the rotating earth, however, this axis will change its orientation in time.
The simplest vertical gyroscope is a free astatic gyroscope, whose axis tends to preserve its orientation in space. The vertical gyroscope is to a large extent free of these disadvantages and therefore is widely used in aircraft, ships, and other moving objects. In addition, rolling may generate induced oscillations of the pendulum with large amplitudes.
However, it is not usable for a moving object, since it will not position itself along the true vertical upon rotational or accelerated translational motion of the object (it will also deviate somewhat from the vertical during a uniform translational motion because of the earth’s rotation). The simplest nongyroscopic device of this type is a physical pendulum (plumb). (also called an artificial horizon), a gyroscopic device for determining the direction of the true vertical or of the plane of the horizon, as well as of the angles of inclination of the object with respect to this plane.