Rigid-elastic Coupling Dynamic Model and Dynamic Characteristics of a Spring-type of Traction Robot

The traditional anchoring mechanism of the traction robot is rigid and is easily stuck in the wellbore. To solve this problem, a novel anchoring mechanism is proposed based on the spring-type of anchoring mechanism of the inclined block. The key to the movement of the traction robot is whether the traction robot can be anchored in the wellbore under the action of the traction force. Therefore, a rigid-elastic coupling dynamic model of the spring-type of anchoring mechanism under the action of the traction force was established. On this basis, the effects of span, width, thickness, and chamfer parameters on the anchoring performance of the spring-type of traction robot were analysed to design the optimal structure of the anchoring arm. Through the experimental comparison, it was determined that the error between the theoretical supporting force and the experimental supporting force was only 6.1%, and the error of the simulated maximum traction force and experimental maximum traction force was 4.9%. The traction robot can provide a maximum traction force of 14262 N in 178 mm (7-inch) of wellbore pipe. Thus, experiments verified the correctness of the rigid-elastic coupling dynamic model. The research results of this paper lay a foundation for the structural design and engineering application of a spring-type of traction robot. It can effectively ensure the downhole safety of oil and gas wells Keywords: spring-type of traction robot, spring-type of rigid-elastic coupling dynamic model, spring-type of anchoring mechanism, motion anchoring Highlights * A novel spring-type of anchoring mechanism of traction robot based on inclined blocks is proposed, which provides a large traction force for the robot and can avoid being stuck * The rigid-elastic coupling dynamic model of the spring-type of anchoring mechanism is established. * The calculation method of boundary conditions of self-anchoring of the traction robot (safe or not) is created. * The maximum traction forces under different structural parameters have been obtained, and the correctness of the theoretical maximum traction force has been verified by experiments