Abstract: A method is set forth for controlling the orientation of an articulated boom of the type having a first portion and a second feed arm portion such that the first portion remains parallel to a predetermined position during movement of the articulated boom. The method utilizes a computer which senses the angular position of the various parts of the boom in a total of five directions and computes the required angular position of the feed arm to maintain it parallel to a set position as the boom is moved in any direction. Various hydraulic servovalves are utilized to control the flow of hydraulic fluid in a manner to maintain parallelism within 1/2.degree. with the referenced position.