DL-RRT* algorithm for least dose path Re-planning in dynamic radioactive environments

Abstract

One of the most challenging safety precautions for workers in dynamic, radioactive environments is avoiding radiation sources and sustaining low exposure. This paper presents a sampling-based algorithm, DL-RRT*, for minimum dose walk-path re-planning in radioactive environments, expedient for occupational workers in nuclear facilities to avoid unnecessary radiation exposure. The method combines the principle of random tree star (RRT*) and D* Lite, and uses the expansion strength of grid search strategy from D* Lite to quickly find a high-quality initial path to accelerate convergence rate in RRT*. The algorithm inherits probabilistic completeness and asymptotic optimality from RRT* to refine the existing paths continually by sampling the search-graph obtained from the grid search process. It can not only be applied to continuous cost spaces, but also make full use of the last planning information to avoid global re-planning, so as to improve the efficiency of path planning in frequently changing environments. The effectiveness and superiority of the proposed method was verified by simulating radiation field under varying obstacles and radioactive environments, and the results were compared with RRT* algorithm output. Keywords: Minimum dose path planning, Sampling-based method, Dynamic environments, Nuclear facilities