| 摘要 |
1512788 Automatic control of gyroscopes SPERRY RAND CORP 6 Aug 1975 [19 Aug 1974] 32827/75 Heading G3R In a gyromagnetic compass system, the azimuthal position of the gyroscope is controlled by a torque motor in response to an error signal derived by a synchro coupled between the gyroscope and a flux valve which detects magnetic meridian data. A threshold device is responsive to gyroscope rotor speed above a pre-set value to limit the torque motor drive signal, and the threshold device is inhibited by a null detector until the drive signal is below another pre-set value, indicating approximate synchronism of the gyroscope and flux valve. As shown, a gyroscope 11 on an aircraft has a rotor 24 driven by an induction motor 12 and connected through a synchro 13 with a conventional flux valve 14. A winding 25 produces a slaving error signal which is amplified 82 and demodulated by a double frequency circuit 87-109 responsive to an AC source 40 which also supplies the motor 12 and the flux valve 14. The demodulated error signal is then coupled to a display device 131 and a high gain feedback amplifier 113 which drives transistors 125,126 to produce a drive signal for a torque motor 15 which sets the gyroscope azimuth. When power is first switched on, a capacitor 111 produces a large pulse voltage which causes the motor 15 to move the gyroscope away from its initial position to prevent stabilization at a false position 180 degrees from the correct attitude. A threshold detector circuit 58 receives a signal on lead 46 representing the rotor speed. When a given speed is reached, a transistor 61 is turned on, and a winding 63 is energized, causing contacts 123 to close and thus limit the gain of the amplifier 113, so that the drive of torque motor 15 is at a low level when full rotor speed is achieved under normal conditions. At start-up, the drive signal produced by transistors 125, 126 is large, and causes a diac 67 to trigger a triac 66, thereby disabling the threshold circuit 58 and ensuring that the drive signal to the torque motor 15 remains at a high level until substantial synchronism is achieved, irrespective of the rotor speed. When synchronism is close, the output of transistors 125, 126 falls to a low level, so that the diac 67 blocks and the triac 66 turns off, allowing the threshold circuit 58 to operate normally. If desired, the aircraft pilot can operate a manual switch 72 which disables the circuit 58 and allows manual synchronization at a high level of torque motor drive. |
