GB1296213A - - Google Patents

Abstract

1296213 Automatic steering control DECCA Ltd 19 Feb 1970 [18 June 1969] 30884/69 Heading G3R An electrical signal for steering a ship is formed by combining a control signal with a feedback signal from a capacitor the charge on which is increased or decreased incrementally according to the direction and extent of movement of a steering motor and also tends to decrease with the passage of time. As shown, any difference between a compass signal 11 corresponding to the course of a ship and a signal 10 corresponding to a desired course is applied through a suitable non-linear circuit 13 and an amplifier 15 to control an electric servomotor 16 operating rudder 18 to correct the course of the ship. Movement of a slotted disc 19 driven by servomotor 16 corresponds to the integral of the control signal applied to servomotor 16 and, by interrupting light from a lamp 21 falling on photocells 20 associated with a discriminator 22, produces pulses which add or subtract increments of charge to a condenser 25 according to the sense of movement to produce a voltage corresponding to the integral. This voltage is applied as negative feedback to the input of amplifier 15 but, to permit offset of the rudder if necessary to counteract persistent unbalance effects, a leakage resistor 27 is connected across the condenser to reduce the feedback as a function of time.