Planning and chemical plant operating procedure synthesis: A case study

Mixing expressiveness and efficiency in a manufacturing planner

“…This subject has also been studied in the literature, with diOE erent degrees of success, but there has always been a need for an increase in expressiveness concerning state-ofthe-art known planners (Aylett et al 1997, Klein et al 1998. However, the plans obtained are still far from being applied since they may lack some actions which could be essential for the execution of a true sequential control program (see Castillo 1998, for more details) as for example, the need to disconnect a device once it has been used.…”

“…However, in Ma c h i n e the end point of the interval depends on the inclusion of a later action which is never prede® ned. In addition to this, in Aylett et al (1997 ) there is no awareness of intervals of execution ; and in Klein et al (1998 ) there are no partially-known intervals and intervals, which are completely known, end with the full achievement of their eOE ects. This last viewpoint does not take into account actions whose eOE ects persist.…”

“…This research area has been dealt with extensively in the literature covering planning techniques which range from classical planning to case-based planning or hierarchical planning, but they are only concerned with a subset of the operations that actually take place in the entire manufacturing systems. Only recently, new eOE orts have been devoted to applying AI planning techniques to synthesize control sequences for the manufacturing system (Aylett et al 1997, Klein et al 1998 in such a way that ® nal plans could be directly used as the sequential control programs which drive the operation of manufacturing systems. This is the subject of this paper.…”

Mixing expressiveness and efficiency in a manufacturing planner

“…This encodes procedural knowledge which forces the planner to include additional actions to leave every agent in a safe state before the end of the plan (in this case, the safe state is (STATE DRILL-UP)). Although this is usual during the writing process of sequential control programs, it is not during a classic planning process and as a result, the plans might lack some essential actions (Aylett et al 1997, Klein et al 1998.…”

“…As an example, the goal of the problem which has been seen so far, speci® ed as a recipe, can be seen in ® gure 9. This is another novel contribution, which is not present in either Aylett et al (1997) or in Klein et al (1998). It is related to the goal representation in GeorgeOE(1991), where a behavior may be represented as conditions which are true at the end of sequences of states, i.e.…”