GB745913A - Maximum control signal limiter for a craft control system - Google Patents

Abstract

745,913. Automatic steering control systems. BENDIX AVIATION CORPORATION. Jan. 15, 1953 [Jan. 23, 1952], No. 1261/53. Class 38 (4). The invention is applied to an aircraft automatic steering system of the type described in Specification 662,831, in which alternating current signals produced by an earth inductor compass 22 upon course deviation control, through a valve amplifier 31, a follow-up servomotor 33 operating an induction device 34 producing an A.C. signal corresponding to course error. This signal is combined with the signal from the pick-off of a rate of turn gyro 23 and applied to an amplifier, comprising valves 41, 49, 55, the output of which controls an A.C. servomotor 57 operating the rudder 19 to restore the aircraft to its course. A limiter 60 of the type described in Specification 693,085, [Group XL (c)], limits the maximum value of the A.C. signal applied to valve 49. One or other of two negatively biased diodes 80, 81, depending on the phasesense of the signal, becomes conductive at the limit to shunt the output circuit of valve 41 and prevents any further increase of the signal applied to valve 49. Bias for the diodes is provided by a full-wave rectifier, including valves 69, 71. - To provide a limiting value of error signal which increases with increasing altitude the A.C. supply to the bias rectifier is varied by a potentiometer 130 adjusted by a follow-up servomotor 117 controlled by the pick-off 111 of a bellows unit 101 which is responsive to altitude and of the type described in Specification 662,918. A bellows unit responsive to aircraft speed may replace that responsive to altitude to decrease the limiting value of error signal with increase of speed.