A new pipeline inclination measurement method using spherical inner detector

Abstract

Spherical inner detector has a large error in measuring pipeline inclination for its difficulty to calibrate pipeline magnetic shield model. Against to this drawback, a new method of measuring pipeline inclination was proposed without using pipeline magnetic shield model. It was based on cycloidal motion characteristics of the sensor in spherical inner detector while rolling inside pipelines, uneven radial distributions of magnetic fields inside after unilaterally magnetized, and the coordinate transformation method. The method uses the acceleration signal to solve the rotation matrix, and then uses the location of the maximum point of the magnetic signal to solve the pipeline inclination. The mathematical model of the method was established while its algorithm was also designed and implemented. This method was verified by simulation and experiments. The experimental results show that they are highly consistent with the simulate results. Good measurement accuracy can be obtained and maximum relative error is 3.55%.

Keywords

• pipeline inclination; spherical inner detector; magnetization; measurement