GB621473A - Improvements in automatic control systems - Google Patents

Abstract

621,473. Automatic control systems for aircraft. SMITH & SONS (ENGLAND), Ltd., S., and MEREDITH, F. W. June 15, 1945, Nos. 15334/45 and 17663/46. [Class 38 (iv)] In an automatic control system a condition is controlled in correspondence with both a measured quantity and its rate of change to a value proportional to the difference between the transient integral of the condition and the measured quantity. As shown, Fig. 1, control of an aircraft elevators is effected to cause the aircraft to be brought smoothly into a radio beam. The difference between the rate-ofpitch-signal generated by the pitch gyroscope 8 and the rate-of-elevated-displacement signal produced by generator 22 is applied to the high gain amplifier 21, which operates the motor 19. The latter drives the elevators 9 through gearing 18, and also drives the generator 22. In addition, the output signal of pitch gyro 8, which has the frequency of the aircraft supply, is fed to circuit 1 where it is demodulated and a transient integral of the signal is produced. Circuit 2 produces a D.C. voltage proportional to the vertical distance of the aircraft from the beam and the difference between the outputs from circuits 1, 2 is supplied to circuit 3 where it is re-modulated and introduced into the input of the amplifier 21 in series with the signals from gyroscope 8 and generator 22, to stabilize the aircraft and cause it to subside on to the beam in pitch. The pitch pendulum 10 is short-circuited to prevent departure from level flight. Similarly, the aircraft may be controlled in yaw and roll. To effect damping of the short period motion of the aircraft, the pitch gyroscope signal is applied to a thermionic circuit, Fig. 5 (not shown), the subject of Specification 654,048. Specification 611,037, [Group XXXV], is referred to.