The Design And Experimental Research Of PIG Odometer

The odometer has been widely used in smart PIG benefiting from its simplicity,reliability and the better adaptability.As a key device for PIG positioning technology,the accuracy of odometer has an important impact on the positioning of the defects and then the location of the excavation point—which affects the efficiency and safety of repairing progress.At the same time,the complex internal environment of the petroleum and natural gas pipeline makes strict demands on the structure and sensors of the wheel.Therefore,it is necessary to design a high-precise odometer and to study the motion of the odometer to reduce measuring error.Based on the background,the research of the odometer structure and motion has been carried out as the followings:(1)In this paper,the overall scheme of an odometer wheel is proposed after sufficient literature survey.In the odometer wheel,an incremental sensor based on rotating magnetic encoding technology is designed to improve the measurement accuracy of odometer wheel and the output characteristics is measured.The design of the key parts,such as the rotary arm,the wheel,the base and the spring,is also given in this paper.(2)The movement process of odometer which causes the errors(passing through the slip,the weld,the defects,the intersections or the elbow)is analyzed.Then,some corresponding measures have been put forward to reduce the measuring errors.(3)The process of odometer passing through pipeline weld and defect is simulated in the ADAMS software,and the influences of the velocity and the preload of spring on the trajectory and angular velocity of odometer are studied.At the same time,the mileage of simulation process is studied.(4)The trajectories of odometer passing through weld or defect are studied experimentally.The actual tracks of odometer passing through weld or defect are investigated and the influence of velocity is studied.The experimental results have demonstrated the validity and applicability of the simulation at low speed.The research of this paper has important engineering significance to improve the accuracy and reduce error of the odometer.