This paper reports on the design and implementation of a real-time executive for a mobile rover that uses a model-based, declarative approach. The control system is based on the intelligent distributed execution architecture (IDEA), an approach to planning and execution that provides a unified representational and computational framework for an autonomous agent. The basic hypothesis of IDEA is that a large control system can be structured as a collection of interacting agents, each with the same fundamental structure. We show that planning and real-time response are compatible if the executive minimizes the size of the planning problem. We detail the implementation of this approach on an 'exploration rover (Gromit, an RWI ATRV Junior at NASA Ames) presenting different IDEA controllers of the same domain and comparing them with more classical approaches. We demonstrate that the approach is scalable to complex coordination of functional modules needed for autonomous navigation and exploration.

Planning and model checking are similar in concept. They both deal with reaching a goal state from an initial state by applying specified rules that allow for the transition from one state to another. Exploring the relationship between them is an interesting new research area. We are interested in planning frameworks that combine both planning and scheduling. For that, we focus our attention on real time model checking. As a first step, we developed a mapping from planning domain models into timed automata. Since timed automata are the representation structure of real-time model checkers, we are able to exploit what model checking has to offer for planning domains. We present the mapping algorithm, which involves translating temporal specifications into timed automata, and list some of the planning domain questions someone can answer by using model checking.

The authors report preliminary work toward the creation of an integrated solution to a transportation planning and scheduling domain within the HSTS temporal planning framework. The reference problem is a simplified domain that displays some of the main characteristics of the complete transportation problem. The transportation problem is outlined. The fundamental characteristics of HSTS are described. The focus is on the representation of multiple capacity resources. The areas considered are how HSTS has been extended to represent aggregate resource capacity, how the simplified domain can be modeled. and a constraint-directed planner that solves transportation problems in the simplified domain.>

The authors describe HSTS, an integrated planning and scheduling architecture that has been applied to the problem of generating observation schedules for the Hubble Space Telescope. HSTS deals with the problem of the interaction of resource allocation and auxiliary task expansion during schedule development by viewing planning and scheduling as two complementary aspects in the construction of the behavior of a system. The authors first describe how HSTS specifies the dynamics of a system, how it represents schedules at multiple levels of abstraction, and the specific problem solving machinery it provides. An example of the use of the architecture in the Hubble Space Telescope domain is given. Performance results that indicate the practicality of the HSTS approach are presented.>