Patent GB-616518-A (GB)
Title: Improvements in and relating to control systems for power-driven movable objects
IPC: G05D3/12
Filed: 1942-12-07
Abstract: 616,518. Automatic control systems. TUSTIN, A., and METROPOLITAN-VICKERS ELECTRICAL CO., Ltd. Dec. 7, 1942, No. 17404. [Class 38 (iv)] [Also in Group XXXVII] Speed.-In a system for controlling the speed of a power-driven movable object, speed is dependent on the displacement of a controller which controls the speed of an auxiliary electric motor, means responsive to the displacement of this motor produce one component of a control quantity for the movable object, movement of which introduces a differential follow-up component, and a third component is introduced dependent on the controller displacement. In Fig. 1, displacement of a hand wheel 2 in either direction. from the position shown results in the selective energization of opposed sections 37, 38 of the variator winding of a metadyne generator 35 supplying a separately excited motor 34 driving a shaft 1 so that shaft 1 rotates in a direction and at a speed corresponding to the direction and amount of the hand wheel displacement respectively. This control is obtained by coupling the hand wheel through gearing 31 to a reversing potentiometer 28 controlling the direction of rotation and speed of an auxiliary electric motor 25, supplied from a constant voltage D.C. source 32, which drives, through gearing 24, the rotor of a selsyn transmitter 6 connected to the stator of a selsyn receiver 5, the rotor of which supplies, through conductors 14, an A.C. voltage dependent in sense and amplitude on the direction and amount of the hand wheel displacement to operate metadyne control apparatus 15 which may be of the thermionic valve type, described in Specification 592,208, [Group XXXVIII], responsive to the sense and amplitude of the A.C. voltage input and its rate of change. Mechanical coupling between shaft 1 and the rotor of the selsyn receiver 5 provides a differential follow-up component of control to stabilize the speed of shaft 1. The A.C. supply from source 9 to the selsyn transmitter is through a third selsyn 4, the rotor of which is connected to source 9 and mechanically coupled to the hand wheel, the stator being connected to the stator of transmitter selsyn 6. This introduces a component of control causing a displacement of shaft 1 corresponding to the displacement of the hand wheel and results in phase advance of sinusoidal components of hand wheel movement to facilitate manual setting of a movable object driven by shaft 1 relative to an arbitrarily moving point. In a modification, selsyn 6 is dispensed with, the stator of selsyn 4 being directly connected to the stator of selsyn 5. In this case the " stator " of either selsyn is arranged for rotation and driven by auxiliary motor 25. In another modification, Fig. 2 (not shown), the arrangement is similar to that just described except that each of the two selsyns is replaced by a resistance control device comprising a toroidally wound resistance wire with three uniformly distributed tappings as the stator co-operating with a pair of diametrically opposite brushes comprising the rotor, one of the " stators " being arranged for rotation by motor 25 as in the selsyn arrangement. In this arrangement the output of the second resistance control device is a direct voltage, the sense and magnitude of which corresponds to the direction and magnitude of the hand wheel displacement. The metadyne control apparatus 15 may then be a pair of vibratory regulators of the type disclosed in Specification 612,516, [Group XX], with the addition of the anti-hunt phase-advancing arrangement of Specification 609,304. In a third modification, Fig. 3, the hand wheel 2 again controls the direction of rotation and speed of auxiliary motor 25 through a reversing potentiometer 28, but the phase-advancing component of control is introduced into the supply to this motor by a separately-excited D.C. generator 60 coupled to the hand wheel, the output of which is in series with the motor supply. Motor 25 drives the rotor of a selsyn transmitter 4 which operates a selsyn receiver 5 to control shaft 1 in the manner of Fig. 1. In a modification, Fig. 4 (not shown), a torqueresponsive controller similar to that described in Specification 577,312, [Group XXXVII], functions as reversing potentiometer in a bridge circuit controlling the armature supply to auxiliary motor 25 and the desired components of control are introduced mechanically by spring, eddy-current or fluid pressure loading. The use of graded reversing potentiometers so that a given angular movement of the hand wheel produces a greater increment of the speed of shaft 1 at large hand wheel displacements than at smaller hand wheel displacements is referred to. Specifications 583,836, 583,838, 583,839, 604,186, 609,204, [all in Group XXXVIII], 609,294, and 609,804, [Group XXXVIII], also are referred to.