Optimal Planning as Constraint Optimization

Enrico Giunchiglia, Armando Taccchella

Keywords: Optimal Planning, Constraint Optimization

TL;DR: A general approach to encoding optimal planning problems into decidable quantifier-free first order theories

Abstract:

We consider the problem of optimal planning in deterministic domains
and reduce it to the problem of finding an optimal solution of a corresponding constraint optimization problem incorporating a bound $n$ on the maximum length of the plan. By solving the latter, we can conclude whether $(i)$ the plan found is optimal even for bounds greater than $n$; or $(ii)$ we need to increase $n$; or $(iii)$ it is useless to increase $n$ since the planning problem has no solution.
Our approach $(i)$ substantially generalizes previous approaches for optimal symbolic deterministic planning; $(ii)$ allows to compute non trivial lower bounds on the cost and length of optimal plans; and $(iii)$ produces an encoding linear in the size of the planning problem and the bound $n$.