GB821231A - Automatic pilots for aircraft - Google Patents

Abstract

821,231. Automatic steering control systems. SPERRY RAND CORPORATION. Jan. 10, 1956 [Jan. 12, 1955], No. 822/56. Class 38 (4). In an aircraft automatic pilot turns are effected by injecting a signal into a servosystem controlling the ailerons in dependence on the angle of bank and a signal dependent on rate of side-slip is injected into a further servosystem controlling the rudder. In Fig. 1, signals corresponding to deviations from a desired heading are developed by an inductive pick-off 11 of a directional gyro 12 and applied through an inductive device 18 to an amplifier 24, the output of which energizes the field of a Ward-Leonard generator 38 supplying a servomotor 37 normally maintaining an aircraft on a straight course by adjustment of rudder 34. A section 28 of amplifier 24 develops and adds a signal corresponding to rate of change of heading. Follow-up is provided by combining with the heading error and rate of change of heading signals a signal developed by an inductive device 33 adjusted with the rudder. Signals corresponding to deviations from a desired angle of bank are developed by an inductive pick-off 49 of a vertical gyro 42 and applied to an amplifier 24<SP>1</SP>, the output of which energizes the field of a Ward-Leonard generator 38<SP>1</SP> supplying a servomotor 37<SP>1</SP> normally maintaining the aircraft level by adjustment of ailerons 50. Amplifier 24<SP>1</SP> includes a section 28<SP>1</SP> for developing and adding a rate component, and follow-up is provided by an inductive device 33<SP>1</SP> adjusted with the ailerons. Turns are effected by operation of an inductive device 51 by a knob 52 to develop a signal which (a) is applied through a smoothing circuit 54 to the input to amplifier 24<SP>1</SP> to set a fixed angle of bank, (b) is applied through a transformer 57 and amplifier 66 to.energize the field of a motor 20 adjusting inductive device 18 so that by virtue of feedback from a tachometer generator 67 it runs at such a speed as to cause turn at the desired rate. Sideslip during turn produced, for example, by rate of turn not suited to the airspeed, results in a voltage across the armature of motor 37 which is applied through a smoothing circuit 70 to a modulator 69, the output of which, through a transformer 73, is applied (a) to the input of amplifier 66 in a sense to correct the rate of turn, and (b) to the input of rate section 28 to modify the rate component in aid of stability. The magnitude of this sideslip signal is made dependent on the angle of bank by rectifying the signal from inductive device 51 by a rectifier 87 and applying it to control modulator 69. When knob 52 is in a central position for straight flight a switch 101 short-circuits the output of modulator 69. In a modification, sideslip is detected by a pendulum operating a potentiometer.