Global Path Planning in Complex Environments Using Metric and Topological Schemes

Global path planning is a challenging problem arisen in many fields of research. It is of particular interest to construction planning community facing the requirements of trustworthiness and feasibility of project schedules. Correct schedules must avoid any conflicting situations at project sites and assure the existence of collision-free paths for installed construction elements and deployed equipment. To validate schedules against potential spatio-temporal conflicts, emerging 4D modeling technologies, collision detection and motion planning methods can be applied. Ultimately it would enable detecting and anticipating problems at earlier planning phases and reducing risks and waste at the final construction phases. Unfortunately, path planning algorithms have relatively high complexity that extremely grows with the input data volume. Most reports have concluded that the algorithms work well in simple 2D environments, but require much larger computation resources in large-scale dynamic 3D environments that makes the stated validation problem highly intractable for construction applications. Being oriented on exact or approximate metric representations, traditional local path planning methods have significant limitations in the case of large-scale environments. Their inability to use overall a priory information on the whole environment creates another shortcoming in global planning. Topological schemas try to overcome these drawbacks by representing the original environment by means of route graphs. Topological schemas scale better than metric ones, but being resistant to geometric representation errors may yield incorrect or suboptimal solutions. In the paper we propose an effective method leveraging global and local path planning strategies and combining metric and topological schemas. Due to original criteria for extracting a topology from metric information, the method is applicable to complex indoor/outdoor environments and can be used for spatio-temporal validation of construction project schedules. Conducted experiments proved the feasibility and effectiveness of the method presented.