Upward-Backtracking Mechanism Infused HTN Planning Approach for Space Operation

To reduce ground operational costs and increase overall capability, space powers are competing to develop autonomous planning system of space operation missions. Hierarchical task network (HTN) is the most widely used method to construct automatic planners. for typical HTN algorithm, if the current state does not support any decomposition prescription, the HTN planner will not try to change the state, but just return failure. This characteristic requires personnel to compile a large prescription database, which is time consuming. to overcome this shortcoming, the paper infuses upward-backtracking mechanism to improve HTN algorithm. When the problem above occurs, the improved planner will search higher level tasks and its subtasks to change the system state to support the decomposition of the mission. the promotion could extend the searching range of planner and reduce the compiling of prescription database largely. a typical space operation task is taken as an example to demonstrate the algorithm´s property.