Patent GB-660575-A (GB)
Title: Improvements in or relating to automatic control systems for aircraft
IPC: G05D1/06
Filed: 1942-02-05
Abstract: 660,575. Automatic steering control systems. SPERRY GYROSCOPE CO., Inc. Feb. 5, 1942 [Feb. 10, 1941], No. 32143/47. Divided out of 660,551. Class 38 (iv). An automatic control system for aircraft, of the kind wherein the departure of an aircraft from a desired direction and attitude produces a controlling effect to restore it to course, comprises means for providing control voltages which are fed over control circuits to motors whereby the direction and attitude are adjusted and the elevation and bank-controlling motors are braked before they attain the positions determined by the control signals. The system is described as applied to the radio-controlled system described in Specification 660,551. A motor 8 operates to change the heading of the aircraft and, to avoid skidding during a turn, the aircraft is banked in proportion to the rate of turn by a bank control motor 32 which is geared to the bank control 23 of the gyro pilot and receives operating signals from a bank control amplifier 35 which derives control signals from a rate-of-turn measuring device 34 responsive to the speed of the turn-control motor 8. A follow-up signal proportional to the angle of bank is applied to the amplifier 35 by a potentiometer network 36 driven from the motor 32, this followup signal being arranged to buck the rate-of-turn signal received from the measuring device 34. In addition, a rateof-bank measuring device 37 is provided for measuring the speed of the bank control motor 32, and feeds back into the amplifier 35 a rate-of-bank signal which exercises a positive braking action on the motor 32 as the combined signal received by amplifier 35 from the rate-of-turn device 34 and potentiometer 36 approaches zero. The elevator control is subject to signals received at an aerial 38a and fed to a motor 40 through an elevator control amplifier 39, the motor being connected to drive the elevator control 25 and a follow-up potentiometer 42 which supplies a follow-up voltage proportional to the vertical directional correction and bucking the signal fed into the amplifier 39 from the glide-path receiver. The upper portion of Fig. 2 shows the direction control unit described in Specification 660,551, and the lower portion the banking control and braking system of the present invention. The amplified direction control signals are fed to the field coil 92 of the twophase motor 8, which coil is associated in an inductance bridge circuit, the other three arms of which comprise inductance 99 and resistance 91 in series, resistance 101, and resistance 102, so that the voltage taken over leads 103, 104 connected across the diagonal of the bridge is proportional to the speed of motor 8. This voltage, which is applied to the primary winding 129 of a transformer 119 as a control voltage for the banking-motor 32 is bucked by the A.C. follow-up signal from a potentiometer 36 with its contact arm geared to the banking-motor 32, and also by a voltage proportional to the speed of that motor. The latter voltage, which provides the braking effect, is derived from a bridge circuit including the field winding 110 of motor 32, inductance 111 and resistance 113, resistance 114, and resistance 112, and is proportional to the speed of the banking control motor 32. The banking-control signal fed to the primary winding of transformer 119 is amplified by resistance-coupled valves 115, 116 feeding push-pull valves 117, 118 connected to an output transformer 123. The braking circuit of the elevator control motor, Fig. 4 (not shown), is substantially similar to that of the banking control system, the bucking voltage derived from a speed-measuring bridge circuit being fed back in opposition to the voltage from the glide path receiver. Specification 660,576, [Group XXXVII], also is referred to.