GB1030873A - Improvements relating to vehicle guidance systems - Google Patents

Abstract

1,030,873. Inductive control of vehicles. ASSOCIATED ELECTRICAL INDUSTRIES Ltd. March 22, 1963 [March 23, 1962], No. 11256/62. Heading H4U. [Also in Division G1] A vehicle guidance system, e.g. for a pair of tractors drawing ploughs or the like, comprises controlling and controlled vehicles, the controlling vehicle carrying means for producing an alternating magnetic field and the controlled vehicle carrying magnetic sensing means arranged to be controlled by the magnetic field to produce an electrical output for the operation of the steering mechanism of the controlled vehicle to maintain it in a predetermined position relative to the controlling vehicle. The controlling tractor T1, Fig. 1 (not shown), carries a device D1 mounted adjustably on an arm AR and comprising a coil C1 on a ferrite core which is energized at a frequency of about 10 kc/s. to produce the magnetic field. The controlled tractor T2 carries a magnetic sensing head D2 adjustably mounted on boom BO and comprising mutually perpendicular coils C2, C3 on ferrite cores and arranged so that when the controlled tractor is moving in the required direction no voltage is induced in coil C3 but a reference voltage is induced in coil C2 dependent upon the spacing d between the two tractors. If the tractor T2 should deviate from its correct course a voltage will be produced in the coil C3 having an amplitude dependent on the amount of deviation and a phase relative to the reference voltage corresponding to the direction of deviation. The voltage produced in coil C3 is compared with that produced in coil C2 and an output derived which controls the steering mechanism to restore the tractor to its proper course. The reference voltage from C2 may be compared with a further fixed reference voltage representing the desired distance between the two tractors to provide an output signal controlling the speed of the tractor T2. The controlled vehicle may itself control a further vehicle in a similar manner. Additional signals such as for raising or lowering a plough or operating a clutch may be provided by further transmitting and receiving heads operating at different frequencies. Alternatively, the signal supplied to head D1 may be modulated, a demodulator on the tractor T2 providing the required auxiliary control signals. The tractor T2 may be arranged to be stopped on receiving a very large signal on coil C2 and a very small signal may be used to start the tractor.