There has been much research dealing with the precise and automated steering of off-road vehicles and agricultural machinery, but because of drawbacks such as cost and technical limitations, they have not been widely adopted in practise. In this study, an interchangeable system with modest cost and limited technical requirements was developed, constructed and tested. It can be installed on most agricultural tractors, and other off-road, self-propelled machines. The system comprised a cable-spreading unit with a slim steel cable, a fifth or ground wheel with some cable-positioning sensors, a control unit and processor along with an electro-mechanical steering wheel driver. A prototype of this system was fabricated and installed on a Massey–Ferguson MF285 tractor with design accuracy of 25 mm. The overall offset deviation (error) on a longitudinal path from the desired path was 26 mmm1 and 27.4mmm1, on soil and asphalt surfaces, respectively. Thus in large fields with long paths, it appears that automatic accurate steering could be achieved with this system.

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