Dietmar Berwanger,
Coordinating Controllers

A comprehensible and rewarding approach to control problems for discrete-event systems consists in viewing them as strategic problems for infinite games on graphs. In this perspective, the task of synthesising controllers for decentralised systems translates into the task of designing coordinated winning strategies for a coalition of players in a game with imperfect information. Unfortunately, this leads to an undecidable problem in the general case.

We track down the undecidability of the general strategy-synthesis problem to the failure of coordination between the players within a coalition. As a way out, we propose an approach to decentralised control in which the task of coordination is addressed explicitely. In extension to the traditional setting where decentralisation regards only the execution, we focus on the requirement of decentralised design. Our framework features a non-cooperative criterion of designer liability which is weaker than the traditional postulate of cooperation, and thus delivers fewer solutions. On the other hand, the approach yields a procedure for decentralised controller synthesis which is decidable in the general case.