A Constraint-based Encoding for Domain-Independent Temporal Planning
This work addresses the problem of improving efficiency in temporal planning for AI researchers and practitioners, but it is incremental as it builds on existing constraint-based scheduling ideas.
The authors tackled the problem of domain-independent temporal planning by introducing a constraint-based encoding that operates at the level of action templates rather than primitive actions, resulting in a simple and compact representation. They showed that this encoding is slightly more efficient than state-of-the-art methods on temporally constrained planning benchmarks and clearly outperforms other fully constraint-based approaches.
We present a general constraint-based encoding for domain-independent task planning. Task planning is characterized by causal relationships expressed as conditions and effects of optional actions. Possible actions are typically represented by templates, where each template can be instantiated into a number of primitive actions. While most previous work for domain-independent task planning has focused on primitive actions in a state-oriented view, our encoding uses a fully lifted representation at the level of action templates. It follows a time-oriented view in the spirit of previous work in constraint-based scheduling. As a result, the proposed encoding is simple and compact as it grows with the number of actions in a solution plan rather than the number of possible primitive actions. When solved with an SMT solver, we show that the proposed encoding is slightly more efficient than state-of-the-art methods on temporally constrained planning benchmarks while clearly outperforming other fully constraint-based approaches.