A Flexible Roadmap of the Safe Hoisting Motion Planning of Blanket Module for Cfert by the Dual Mover Robot System

Abstract

The China Fusion Engineering Experimental Reactor (CFETR) project, a national scientific device, as well as the largest international cooperation in the world, is the most effective technique for solving the human energy crisis, whose maintenance system design is also a prerequisite for future commercial magnetic confinement fusion reactors. This project focuses on the maintenance of the blanket by the Mover robot. Firstly, the huge blanket module maintenance is planned in a narrow workspace of CFETR, which has a big risk of damaging other delicate devices. Hence, the topic of blanket's hoisting motion planning is necessary so that a novel method is proposed, in which the feasible region of the workspace is converted into multiple graph convex sets, and a shortest path problem (SPP) model is established which would use the mixed integer convex programming (MICP) method to solve this model for a smooth collision-free trajectory. Secondly, to ensure trajectory tracking accuracy and stability of the Mover robot system, in the above optimized irregular space complex trajectory, a motion controller with a nonlinear model predictive controller (NMPC) as the inner speed loop and PI as the outer position loop is designed. Finally, due to the heavy payload, the maintenance robot, Mover, is designed with hydraulic drive mode, and a corresponding data monitoring and safety warning model was established by kernel principal component analysis (KPCA) to monitor the hydraulic elements to prevent leakage, pollution, and other extreme cases. Besides, the reason for applying the KPCA model is that the number of hydraulic elements is huge and the KPCA behaves well in nonlinear analysis with a high-dimensional system. All in all, the proposal aims to solve complex motion planning for hosting blanket by the Mover system and safety monitoring problems and explore new ideas for intelligent maintenance technology of fusion devices.

Keywords: motion planning, CFETR remote handling, hydraulic robot, optimization of graphs of convex sets