GB1322897A - Automatic steering arrangements - Google Patents

Abstract

1322897 Automatic steering control E M I Ltd 7 Sept 1970 [12 Sept 1969] 45014/69 Heading G3R In an automatic steering system, signals are applied to an angle resolver, the output of which controls the steering and the rotor of which is coupled to the steering to ensure proportionality between the steering angle and the ends. As applied to the automatic steering of an eightwheel container carrier, pairs of coils 18, 19 and 20, 21 are respectively fixed at positions 13 and 12 relative to one of the front wheels 1 so that they are equally spaced on each side of a buried conductor (not shown) carrying AC and defining a route to be followed by the carrier. Coils 18 and 20 are connected together so that the voltages induced in them subtract and coils 19 and 21 are connected together so that the voltages induced in them add. The two resultants are amplified and applied to rotor windings 24, 25 of an electromagnetic resolver so that deviation from the route produces an output of corresponding magnitude and sense from a phase sensitive detector 30 supplied by amplified signals from resolver stator windings 26 and 27 and which controls an hydraulic actuator 5 to correct the course of the carrier by turning wheel 1 about a vertical axis. When wheel 1 turns, it moves resolver rotor 15 through a flexible link 16/17 to provide follow-up and ensure correspondence between the angle of turn and the magnitude of the error. The other wheels of the carrier are coupled to wheel 1 so that they move through suitable angles to facilitate a turn. Sensitivity may be maintained constant despite changes of coil height by automatically controlling the amplification of signals from stator winding 27 in dependence on the output from stator winding 26. In an alternative arrangement, the coil voltages may be applied to the resolver stator windings and the output taken from the resolver rotor windings.