In artificial intelligence, action description language (ADL) is an automated planning and scheduling system in particular for robots.
Pednault observed that the expressive power of STRIPS was susceptible to being improved by allowing the effects of an operator to be conditional.
This is the main idea of ADL-A, which is roughly the propositional fragment of the ADL proposed by Pednault,[2] with ADL-B an extension of -A.
A third variation of ADL is ADL-C which is similar to -B, in the sense that its propositions can be classified into static and dynamic laws, but with some more particularities.
[3] The sense of a planning language is to represent certain conditions in the environment and, based on these, automatically generate a chain of actions which lead to a desired goal.
Contrary to STRIPS, the principle of the open world applies with ADL: everything not occurring in the conditions is unknown (Instead of being assumed false).
An Update group consists of a set of clauses of the forms shown in the left column of the figure 2: The formal semantic of ADL is defined by four constraints.
In fact most of the planners (FF, LPG, Fast-Downward, SGPLAN5 and LAMA) first translate the ADL instance into one that is essentially a STRIPS one (without conditional or quantified effects or goals).
The necessary actions would be loading, unloading and flying; over the descriptors one could express In(c, p) and At(x, A) whether a freight c is in an airplane p and whether an object x is at an airport A.