Radio Control Used In Operation Of Tractor

Press, Volume XCVIII, Issue 28938, 4 July 1959, Page 8

Radio Control Used In Operation Of Tractor

It may perhaps not be too much to hope that some day a farmer may be able to operate his tractor in the field by watching a radar screen and turning a few knobs to control the movement of the machine while he is still lying in bed. Mechanically minded farmers will have been interested in a report of the appearance of a radio-controlled tractor in Palmerston a few days ago. By

moving a switch on a small transmitter supported by a strap in front of him, the operator was able to control the movement of the machine though it was several hundred yards away from him. In England the driverless tractor has been controlled by a man driving another tractor in the same field. The radio-controlled tractor now being operated in this country carries a receiver powered from the main battery which operates a crystal controlled carrier frequency of 27.00 megacycles a second, and is provided with eight separate, but not simultaneous, channels operated by eight spaced audio . frequency modulations of the carrier. These operate their appropriate tuned reed relays which in turn operate second relays which control the final hydraulic or electric servo-actua-tors.

The channels give the following facilities: (1) steering left; (2) steering right; (3) clutch out; (4) clutch in; (5) implements raise; (6) implements lower; 7 and 8 are spare channels. In addition the carrier operates an engine stop device by a further control so arranged that failure of carrier or local power also causes the engine to stop. A standard . “power assisted steering” pump and tank are used to feed the steering and clutch operating cylinders by solenoid operated valves. The clutch cylinder has a slow one-way bleed valve to ensure smooth take up of the clutch.

The implement “raise ’lower” lever is operated by an electric motor driven linear actuator provided with end and centre switches to give the correct arc of movement to the lever.

The transmitter is powered by a small six-volt self-contained accumulator carried on the outside of the case. A shoulder carrying strap enables the transmitter to be conveniently supported while operating the control switches situated on the top panel. An extendable aerial is mounted on the case. The carrier is crystal controlled to ensure frequency stability.