GB801941A - Improvements in or relating to control systems for steering a craft - Google Patents

Abstract

801,941. Automatic steering control systems. BENDIX AVIATION CORPORATION. Feb. 28, 1956 [March 4, 1955], No. 6222/56. Class 38 (4). [Also in Groups XXIX and XXXIII] In a steering control system for a craft, manual operation of a control stick produces elastic deformation of the stick transversely to its length between two longitudinally spaced sections and thereby relatively displaces two elements of a pick-off to generate an electric signal controlling servo-operated steering gear. In an aircraft autopilot pitch attitude is automatically stabilized by an artificial horizon 21, Fig. 1, A.C. signals from the pitch pick-off 50 of which control the elevators through an amplifier 14 and servomotor 17. Follow-up is provided by an inductive device 54 operated with the elevators. Similarly, bank attitude is automatically stabilized by the artificial horizon, signals from the bank pick-off 36 of which control the ailerons through an amplifier 13 and a servomotor 16. Follow-up is provided in this case by an inductive device 30 operated with the ailerons. To stabilize the heading automatically, signals from an earth inductor compass 19 control the bank attitude through a follow-up type servo-system 20 operating, through a clutch 22 an inductive device 24 in the input of amplifier 13. Properly co-ordinated turns are ensured by a rate-of-turn gyro 18, signals from an inductive pick-off 40 of which control the rudder through an amplifier 12 and servomotor 15. Follow-up is provided by an inductive device 43 operated with the rudder. Each of the servomotors 15, 16, 17 is of the electric induction type, the reference phase winding of which is energized through adjustable transformer 60, 61 or 62 so that motor torque is limited to permit direct mechanical movement of the control surfaces if more than a predetermined force is applied to a manual control column 8 and/or pedals 9. Control column 8 is moved in a fore-and-aft direction to produce pitch and in a transverse direction to produce bank. When a force less than that necessary to overcome the servomotors is applied to control column 8, inductive devices 64, 65, sensitive to strain of the control column when moved in the fore-and-aft and transverse directions respectively, produce signals which are respectively applied to the aileron and elevator control channels so that powerassisted banking and pitching of the aircraft is obtainable. Low-pass filters 70, 71 eliminate unsteady movements of the control column. As shown in Fig. 2, strain of the control column produces relative movement between members 119, 171 respectively attached by clamps 107, 109 at spaced points along control column 8. Inductive devices 64, 65 are mounted on member 119 and their rotors are respectively operated against springs by member 171 when the control column is moved in the fore-and-aft or transverse direction. Specifications 662,831, 662,858 and 781,346, [Group XXIX], are referred to.