| 摘要 |
1,207,336. Gyroscopic apparatus. GENERAL ELECTRIC CO. Oct.19, 1967 [Dec.12, 1966; Dec.13, 1966], No.47736/67. Heading G1C. A gyroscopic device comprises a gyroscope having an inner gimbal 32, a rotor mounted on the inner gimbal for rotation about a spin axis A1-A2 and an outer gimbal 33 mounted on a support 36 for rotation about a major axis C1-C2, the condition of gimbal lock, i.e. alignment of the spin and major axes caused by manoeuvre of the support, being prevented by a stop device in conjunction with a rate sensor which determines the rate at which the gimbal lock position is approached. The stop device causes a 180 degree rotation of the outer gimbal and the spin axis is restored to its position prior to the manoeuvre of the support. It can be shown that for a given gimbal closure rate or rate of approach of the spin and major axis there is a fixed spin axis error on rotating the outer gimbal by 180 degrees. Two methods are available for correcting this error, namely: a) a fixed stop device is used and the gimbal closure rate is fed to apparatus which calculates the spin axis error for that gimbal closure rate. The apparatus energizes a torque so that the spin axis is precessed to nullify the error. b) the gimbal closure rate is fed to an adjustable stop means which determines and fixes the stop angle or minimum angle between the spin and major axes to ensure zero error in the spin axis orientation at the measured gimbal closure rate. Figure 6 illustrates method (a) in which the gimbal closure rate is measured by an electrical generator 51, the rotor of which is coupled by a shaft 52 to an inner gimbal tension 34. The apparatus 55 provides an output voltage which is amplified by an amplifier 45 and energizes torquing means 42. A fixed stop pin 54 strikes the outer gimbal to produce its 180 degree rotation. Several other methods of measuring the gimbal closure rate are also described and include a separate rate gyro, a slider and slidewire in conjunction with a differentiating circuit, an accelerometer in conjunction with an integrating circuit or the time for the 180 degree rotation of the outer gimbal may be determined since this time is inversely proportional to the square root of the gimbal closure rate. For method (b), several examples of adjustable stop means are described such as arrangements of pistons which automatically set the correct stop angle by adjusting the position of a stop cam in dependence on the gimbal closure rate. A solenoid, the coil of which is energized by the signal from a closure rate sensor so that the solenoid plunger is moved to the correct stop position, may also be used or an electric motor may control the position of a stop pin. Fig. 1 (not shown) illsutrates the stop device on a directional gyro to the outer gimbal of which a compass card is attached, a stationary index being mounted on one of the gyro supports to enable the compass to be read. |
