GB1037137A - Improvements in or relating to stabilising apparatus - Google Patents

Abstract

1,037,137. Automatic position stabilization. FINDLAY, IRVINE Ltd. May 14,1965 [Feb.14, 1964; Oct. 27,1964], No.'s 6395/64 and 43810/64, Heading G3R. In a system in which a servo-mechanism maintains a body in a desired attitude, deviations of the body are detected by variations of liquid level in a U-tube forming a capacity in an A.C. circuit controlling the servo-mechanism. As applied to ship roll stabilization, mercury in a glass U-tube, having a restriction to provide damping, forms one electrode of a differential capacitor with the other electrodes outside the tube. This differential capacity is included in an A.C. bridge circuit the output of which, being dependent on the angle of roll, controls, through a transistor amplifier, a solenoid-operated hydraulic actuator for stabilizing fins on the ship. Signals dependent on rate of roll and roll acceleration are obtained by differentiation and added to the angle of roll signal. In one modification a pair of U-tubes are used with opposite capacitors connected in parallel and one U-tube being maintained in a datum position by a gyro to eliminate signals due to transverse acceleration. In another modification both electrodes are outside the U-tube and the liquid within forms the dielectric. Use of U-tubes with only one capacitor limb, manually adjustable capacitors to provide temperature compensation or correct list, and control of water flow between tanks on each side of the ship instead of controlling fins, is referred to.