GB791055A - Improvements in or relating to remote control servo systems - Google Patents

Abstract

791,055. Automatic steering control systems. BRITISH MESSIER, Ltd. Jan. 4, 1956 [Jan. 5, 1955], No. 358/55. Class 38 (4). [Also in Groups XXIX and XXXVIII] A remote control servo-system comprises a manually operable lever 1 and an automatic control unit 40 which lever and unit can be selectively connected to a controller 6 in a closed loop including a first servomotor 11 and the controlled element which element is also connected to a second controller 20 in a closed loop including a subsidiary servomotor 25 and a second controlled element 27 having a lost motion or spring connection with the manually operable lever 1. As described applied to an aircraft control, the pilot's stick 1 and the autopilot 40 can be selectively connected by a selector switch 5 to the controller 6 which may be an electronic or electromagnetic amplifier. In the first case a signal corresponding to any movement of the stick 1 is transmitted by a potentiometer 3 to the controller 6 which through a line 7 is connected to an electrohydraulic relay valve 10 which controls an hydraulic servomotor 11 operatively connected via a pair of rods 12, a yoke 13, a shaft 14 and a linkage 15 to the controlled element (not shown), e.g. elevators, ailerons, rudders or fluid jets. The shaft 14 carries a potentiometer 16 by which a signal indicative of the actual position of the controlled element is fed back to the controller 6 via the line 17. The controller 6 compares its two input signals and the arrangement is such that the yoke 13 is moved at a rate proportional to the difference between the signals and in a direction to reduce such difference to zero. A signal indicative of the actual position of the controlled element is also transmitted by a potentiometer 18 to the second controller 20 which also receives, via a potentiometer 29, a signal indicative of the position of the yoke member 27 which is connected by springs 31, 32 to the stick 1. The output of the controller 20 depends on the difference between its two input signals and is transmitted by a line 21 to an electro-hydraulic relay valve 24 which controls the subsidiary servomotor 25 which adjusts the position of the yoke member 27 to follow the stick 1. When the auto-pilot 40 is in use the selector switch 5 is positioned so that the first input signal to the controller comes from the autopilot. The servomotor 11 is operated as before to position the controlled element and the subsidiary servomotor 25 operates to move the yoke 27 which through the springs 31, 32 postions the stick 1 accordingly. There may, as shown, be provided means 42, e.g. gust detecting means, for detecting one or more additional external influences and superimposing signals corresponding thereto on the first input signal to the controller 6. Specification 712,329, [Group XXIX], is referred to.