GB1428908A - North seeking gyro pendulum - Google Patents

Abstract

1428908 Automatic control of attitude BODENSEEWERK GERATETECHNIK GmbH 29 Oct 1974 [8 Dec 1973] 46859/74 Heading G3R [ Also in Division G1] A north-seeking gyro pendulum comprises a .gyro unit within a main casing 12 suspended by a tape 10 and having a north seeking gyro directing torque acting thereon, pick-off means for producing a signal indicative of the azimuth deflection of the gyro unit from a tape centre position, and a torque motor 30 to which the signal is applied via an amplifier 24. The gyro unit 12 comprises a pair of gyros having mutually inclined spin axes 34, 36, the gyros having, in use, equal angular momenta and being pivoted about vertical axes 42, 44, the gyros being coupled together to carry out equal and opposite rotational movements and being resiliently restrained to a rest position, the period of the azimuth oscillations of the gyro unit being equal to the period thereof about the angle bisector of the axes 34, 36. The gyros are interconnected, in the embodiment shown, by a linkage 48 comprising lever arms 50, 52 fixed, respectively to the pivot points of gyro casings 38, 40, a link 54 being pivotally connected to the free ends thereof. One end of arm 52 is coupled to an intermediate point between the ends of tensioned spring means 58 fixed to the main casing 12. A mathematical treatment shows that with suitable choice of the values of various parameters the two periods of oscillation may be equalized and "rectifier effect" problems eliminated i.e. problems resulting from the different moments of inertia of a gyro unit about the gyro spin axis and an axis at right angles to the spin axis and the tape axis.