PIPELINE MANDREL POSITIONING CONTROL SYSTEM

摘要

A method and apparatus is provided for automated control and positioning of a mandrel (20) within a pipe (22) during bending operations. Position detectio n is accomplished by means of a low frequency electromagnetic signal transmission from a coil (36) placed in close proximity parallel to the pipe outer surface. This signal is detected by a pair of orthogonal receiving coi ls (42, 44) mounted on the mandrel in close proximity to the pipe inner surface . The phases of the received signals with respect to the transmitted signal an d the ratio of the amplitudes of the two received signals is used to estimate the relative position of the transmitter and the receivers. Control of the mandrel along with transmission of reference phase information is accomplish ed via a high frequency direct sequence spread spectrum radio link between a computer console (40) outside the pipe mounted on the bender (32) and a computer unit (48) mounted inside the pipe on the mandrel.