Study on Autonomous Pipeline Maintenance Robot. 9th Report, Mechanism and Control Method of Mark V Robot with Lazy Tongs Mechanism.

Abstract

This paper deals with a mechanism and control method of a module-type mobile pipeline maintenance robot to clarify the adaptive feasibility of a lazy tongs mechanismto various diameters of pipeline. The robot basically consists of three modules with two joints, respectively between adjacent modules and is capable of straight and spiral maneuvering along the outside of a pipeline. Furthermore, the robot is capable of changing the length of its arm in order to move on the pipeline of various diameters, from 25 A to 100 A and of passing over obstacles such as reducers, flanges and other equipment. As the control method of the robot is very complicated, the modified dual control mode is introduced by employing the coordinate transformation matrices. The control method of passing over a reducer is shown with some calculated results. The compensating torque for the gravitational force is applied to each module independently to keep the holding force constant and to yield better diagnostic results.