Multilevel Coordination Control of Partially Observed Modular DES

Coordination control for multi-level discrete-event systems is generalized to supervisory control with partial observations. The multi-level system architecture is in this paper restricted to three levels, which include two levels of coordination on the two highest levels. At Level 1 a coordinator coordinates several coordinators of Level 2 and at Level 2 each coordinator coordinates a set of subsystems of Level 3. The problem is to synthesize a set of supervisors based on partial observations and on top-down synthesis, which together achieve the control objectives. A necessary and sufficient condition for the existence of such supervisors is three-level conditional controllability and three-level conditional observability. A procedure is formulated and proven (Theorem 16) to construct the supremal three-level conditionally controllable and conditionally normal sublanguage of the specification language.