Deterministic planning assumes that the planning evolves along a fully predictable path, and therefore it loses the practical value in most real projections. A more realistic view is that planning ought to take into consideration partial observability beforehand and aim for a more flexible and robust solution. What is more significant, it is inevitable that the quality of plan varies dramatically in the partially observable environment. In this paper we propose a probabilistic contingent Hierarchical Task Network (HTN) planner, named High-Quality Contingent Planner (HQCP), to generate high-quality plans in the partially observable environment. The formalisms in HTN planning are extended into partial observability and are evaluated regarding the cost. Next, we explore a novel heuristic for high-quality plans and develop the integrated planning algorithm. Finally, an empirical study verifies the effectiveness and efficiency of the planner both in probabilistic contingent planning and for obtaining high-quality plans.

翻译：确定性规划假设规划过程沿完全可预测的路径演进，因此在实际应用中大多丧失实用价值。更现实的视角是，规划应当预先考虑部分可观测性，并寻求更灵活稳健的解决方案。更为关键的是，在部分可观测环境中，规划质量必然存在显著差异。本文提出一种名为高质量应急规划器（HQCP）的概率性应急分层任务网络（HTN）规划器，用于在部分可观测环境中生成高质量规划。我们将HTN规划的形式化方法扩展到部分可观测场景，并基于代价进行评估。继而，我们探索了一种面向高质量规划的新型启发式方法，并开发了集成规划算法。最后，实证研究验证了该规划器在概率性应急规划及获取高质量规划两方面的有效性和效率。