Implementing soft real-time agent control

This paper describes a real-time environment requiring distributed control, and how the existing multi-agent technologies are modified to meet this need.

Abstract

Real-time control has become increasingly important as technologies are moved from the lab into real world situations or physical simulations. The complexity associated with these systems increases as control and autonomy are distributed, due to such issues as precedence constraints, shared resources, and the lack of a complete and consistent world view. In this paper we describe a realtime environment requiring distributed control, and how we modified our existing multi-agent technologies to meet this need. Two types of enhancements are covered: those which enable planning to meet real-time constraints, such as our task representation, metalevel costing, alternative plan selection, and partial-order scheduling, and those which facilitate on-line real-time control, including scheduling flexibility, caching, and windowed commitments. 1. OVERVIEW An important aspect of most real-world systems is their ability to handle real-time constraints. This is not to say that they must be fast or agile (although it helps), but that they should be aware of deadlines which exist in their environment, and how to operate such that those deadlines are reasoned about and respected as much as possible. This task can become harder yet when the system is distributed, as the ability of a component to meet its deadlines can depend on the performance of another component not under its control. Conversely, a particular component in such a system should be able to reason about both its local deadlines, and those imposed on it through interactions with other parts of the system. In this paper