GB851712A - Improvements in automatic control apparatus - Google Patents

Abstract

851,712. Automatic control systems for aircraft. MINNEAPOLIS-HONEYWELL REGULATOR CO. Oct. 17, 1956 [Oct. 17, 1955], No. 31672/56. Class 38 (4). In a closed loop control system a displacement error signal is combined with a rate signal derived through high and low-pass circuits so that the magnitude of the rate signal varies with frequency. In an aircraft autopilot, Fig. 2, A.C. signals dependent on deviations of pitch from an attitude set by a trim potentiometer 143 are produced by a gyro vertical 30 operating a potentiometer 147. The magnitude of these signals is varied by a potentiometer 150 which is automatically adjusted in dependence on altitude. Added to these signals, through a transformer 48 are signals developed by gyros 65 and 168 operating potentiometers 101 and 161 respectively. The relative magnitudes of the signals from the pitch rate gyros is adjustable by potentiometers 106, 74 and the magnitude of their combined effect is adjustable by a potentiometer 82. The resultant of the pitch attitude and rate signals is applied through a discriminator-amplifier 120 to control a twophase induction motor 155. Follow-up signals are developed by a potentiometer 112 and a generator 180 driven by motor 155. The time constant of the servo-system including motor 155 is set, e.g. automatically in dependence on dynamic air pressure, by adjustment of a potentiometer 191 controlling the magnitude of feedback from generator 180. Motor 155 thus acts as a low-pass integrator of the signals controlling it and signals from potentiometer 112 adjusted by it are added to the signals from the pitch rate gyro 65 and applied through a discriminator amplifier 15 to control a reversible servomotor 16 correcting pitch by adjusting the elevators (not shown). The inclusion of the signals from gyro 65 in the output and input circuits of integrator 155 produces a high-pass effect on the rate signals from gyro 65. Followup signals are developed by a potentiometer 87 driven by servomotor 16 and the magnitude of these signals may be set by potentiometers 94 and 96 the latter of which is automatically adjusted in dependence on the ratio of dynamic to static air pressure. Up-elevator signals during a turn are developed by a potentiometer 131 adjusted by gyro vertical 30 and applied to the input of discriminator-amplifier 120. The magnitude of these signals is varied by a potentiometer 136 automatically adjusted in dependence on altitude.