GB669577A - Improvements in or relating to electrical control systems for controlling the position or orientation of an apparatus unit - Google Patents

Abstract

669,577. Control of D.C. motors. SPERRY CORPORATION. Feb. 26, 1948. [Aug. 19, 1943] No. 9592/49. Divided out of 669,550. Class 38 (iii). The speed of a Ward-Leonard motor 84 in a gun-sight control system is varied by a control member (e.g. a handwheel 19), so that successive equal displacements of this member from its zero position produce progressively increasing increments of motor speed. A potentiometer 278 is connected with its ends at positive and negative potentials and the midpoint of a potentiometer 285 is earthed, the sliders 377, 287 being connected together through their shaft 276, which is driven by the handwheel 19, through a magnetic clutch. When this clutch is de-energized a spring. Fig. 3 (not shown), moves the sliders to their mid-positions (i.e. zero position). When the handwheel 19 is rotated, one signal is produced in the lead 304 proportional to the speed of displacement of the wheel 19 by a generator 282, and another signal is produced by the displacement of the potentiometer sliders 277, 287. The motor 84 (driving the gun-sight in azimuth) is controlled by the signal at 304 through an amplifying system described in Specification 669,550, [Group XXXVIII], whichincludesa a regenerative signal related to armature torque and degenerative signals related to rate of change of armature torque and to motor speed. The control system provides the operator with an aided-tracking system in which the ratio of rate-tracking (i.e. angular velocity of target) to displacement-tracking (i.e. velocity of target) increases as a target approaches. The magnetic clutch avoids damage which might be caused if the apparatus were brought into use with a large signal applied at 304. Specification 616,518 also is referred to.