Tham khảo tài liệu 'autonomous underwater vehicles part 12', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Embedded Knowledge and Autonomous Planning The Path Towards Permanent Presence of Underwater Networks 209 GENERATE Step 0 REPLAN REPAIR q -1 q q -1 q H0 generate ground Fig. 7. Schematic representation of the autonomous mission generation replan and repair processes using partial plan representation of the mission plans. Mission plan adaptation agent This section describes the mission environment model used by the mission plan repair techniques presented in this chapter. We continue using the mission environment model previously described. We generalise this model to any step q in the mission execution timeline. An instance of an UUV mission environment at a given step q can be simply defined as Hq Lq OqJ. The mission domain model Lq contains the set of propositions defining the available resources in the system Pv and the set of actions or capabilities Av. The mission problem model Qq contains the current platform state Xq and the mission requirements Qo . Based on this model we analyse how to calculate mission plans on the plan space Sacerdoti 1975 . A plan space is an implicit directed graph whose vertices are partially specified plans and whose edges correspond to refinement operations. In a real environment where optimality can be sacrificed by operability partial plans are seen as a suitable representation because they are a flexible constrained-based structure capable of being adapted. A partial plan ty is a tuple containing a set of partially instantiated actions and a set of constraints over these partially grounded actions. Constraints can be of the form of ordering constraints interval preservation constraints point truth constraints and binding constraints. Ordering constraints indicate the ordering in which the actions should be executed. Interval preservation constraints link preconditions and effects over actions already ordered. Point truth constraints assure the existence of precondition facts at certain points of the plan. Binding constraints
