Safely adapting a hierarchical reactive system
Damian M. Lyons, Antonius J. Hendriks · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1993
This paper builds upon work in developing a theory of planning as adaptation of a reactive system. In previous work, we introduced the planner-reactor architecture and investigated the structure of the reactor and the planner. In this paper we present our results in representing hierarchical reactive systems and in making safe structural adaptations to an ongoing reactive system. This work is done in the context of automated robotic kitting for assembly and the examples in this paper are taken from this area. Although hierarchical representation is essential for complex tasks, it poses the problem that it may destroy the reactiveness of the system. We demonstrate that it is possible to choose a `flat' representation that both preserves reactivity and allows hierarchical structuring. Previous work on modifying ongoing reactive systems has not addressed the crucial issue of making the modifications in a safe and consistent manner. We present a set of desirable properties for an adaptation mechanism: safeness (reactions aren't interrupted), consistency (use only the old reactions or only the new ones), and boundedness (the changes will eventually occur). We then introduce an adaptation mechanism that has these properties.