GB1210373A - Improvements in or relating to ships' roll stabilizer control systems - Google Patents

Abstract

1,210,373. Automatic stabilization of ships. MUIRHEAD Ltd. Oct. 9, 1968 [Oct. 24, 1967], No.48206/67. Heading G3R. In a ship roll stabilization system, carrier signals at the frequency of the ship's normal electrical supply and a higher frequency are modulated in dependence on roll and, after conversion of the higher frequency modulated signal to one at the ship's supply frequency, the two signals at this frequency are combined to control a torque opposing roll. In a system as shown for stabilizing a ship against roll, synchro transmitters 2 and 3 produce electrical signals dependent on roll rate from a rate gyro 1 on the ship. The signal from transmitter 2 is at normal ship supply frequency while that from transmitter 3 is at a higher frequency supplied by an oscillator 4. This latter signal is converted to D. C. at 5 and applied to a differentiator 6 and an integrator 7 so that signals dependent on roll acceleration and roll are combined in suitable proportions by a modulator 10 the output of which, at ship supply frequency, is added to a suitably proportioned roll rate signal from transmitter 2. The three-term signal controls through an amplifier 16, demodulator 17, and electronic buffer stage 18, a fluid-pressure follow-up servosystem 19, 20 operating stabilizing fins 21. A further signal from a transmitter 12 associated with a damped pendulum 11 is added to the control system to ensure that the ship is stabilized about a vertical position.