GB690670A - Apparatus for damping oscillations of manually controlled dirigible craft - Google Patents

Abstract

690,670. Automatic stabilizing systems. SPERRY CORPORATION. June 13, 1951. [June 14, 1950], No. 14027/51. Class 38 (iv). [Also in Group XXXVIII] Manual control (e.g. steering) of a craft is assisted by a servo-stabilizing system responsive only to short-term disturbances and not to steady turning during manoeuvring in order to damp oscillations of the craft about that axis, by acting on the manually-controlled surface. Means are provided to allow the pilot to operate against the servomotor. Deriving short-term signal.-In a steering system, a directional gyro 13 has a Selsyn pickoff 16 linked to a conventional servo-driven Selsyn repeater 17 system comprising amplifier 28, servomotor 24 and velocity feed-back generator 31. During a quick turn or oscillation of the craft the repeater looses correspondence with the gyro due to the time lag in the motor drive, and the error signal is used to drive the stabilizing system. Alternatively the turn signal may be injected into a decay device (e.g. series capacitor and resistor with a D.C. signal) and the output fed to the servo stabilizing system. Stabilizing system.-The error signal is fed through a rate-taking network such as that described in Specification 612,426 to the rudder servo system comprising an amplifier 39 energizing the fields 47 of a Ward Leonard generator 46 driven by a constant-speed motor 48 and supplying the rudder servomotor 42. Displacement feed-back from a Selsyn 52 centralizes the rudder in the absence of a control signal. Manual control.-Displacement of the rudder 10 by foot-pedals 12 would be opposed by displacement feed-back on the servo system. To overcome this, an output from the servo generator 46 is taken to an integrating or delay network 56 and after modulation fed into the amplifier circuit in opposition to the displacement feed-back whereby a persistent torque produces a slowly developing signal to reduce the effect of the displacement feed-back and allow the pilot to overpower the servomotor. Alternatively a flexible manual controller with a flexure-responsive pick-off connected to the servo-amplifier as in Specification 612,804 may be used to provide a power-assisted manual control.