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.