Variable-curvature elephant trunk robot in nuclear industry

Abstract

In this paper, a variable curvature Elephant trunk robot (ETR) is designed based on the bionic principle to complete the visual inspection and assisted flaw detection tasks in the bottom of the divertor and the vertical port complex pipe area of the China Fusion Engineering Test Reactor (CFETR). It offers a miniaturized and lightweight structure with similar load capacity and position accuracy to a rigid robot. It can be installed as a sub-system of the CFETR remote handling maintenance system on various mobile maintenance platforms such as the CFETR multipurpose overload robot and can penetrate various confined spaces and multi-obstacle environments to complete operational tasks. The kinematic model of the ETR is established based on the Denavit Hartenberg (DH) method. A prototype is built according to the design method and trajectory tests are carried out to verify the rationality of the structural design. For ETR trajectory control requirements, three different trajectory tracking control methods are proposed in this paper. The effectiveness of the trajectory tracking methods is verified by simulation. The Elephant Trunk Robot design and control strategy provides a reference for narrow space maintenance task in the CFETR.