O-Plan is an AI planner based on previous experience with the Nonlin planner and its derivatives. Nonlin and other similar planning systems had limited control architectures and were only partially successful at limiting their search spaces. O-Plan is a design and implementation of a more flexible system aimed at supporting planning research and development, opening up new planning methods and supporting strong search control heuristics. O-Plan takes an engineering approach to the construction of an efficient domain independent planning system which includes a mixture of AI and numerical techniques from Operations Research. The main contributions of the work are centred around the control of search within the OPlan planning framework, and this paper outlines the search control heuristics employed within the planner. These involve the use of condition typing, time and resource constraints and domain constraints to allow knowledge about an application domain to be used to prune the searc...

O-Plan2 is an AI planning architecture which supports research into a number of aspects of planning, scheduling and control. It is based on earlier work on the O-Plan System which was directed towards plan generation. The paper explores the different types of choice ordering decisions which need to be made in an architecture for command and control. The mechanisms for choice ordering and selection in the original O-Plan system were found to be too general for efficient use for all purposes. The paper describes a number of choice ordering mechanisms provided in the O-Plan2 Architecture which provide specialised mechanisms more suited to the range of different ordering problems that arise in planning, scheduling and control applications.