FUZZINESS AND CONSTRAINTS PROGRAMMING FOR AGVs SYSTEM CONTROL

摘要

The subject matter of the study is a deadlock-free supervisory control for automated guided vehicles (AGV) that operate in a common workspace of a flexible manufacturing system (FMS). An AGV provides load/unload services to some workstations while moving along a cyclic transportation route. So, since transport and service operations are repetitive, hence the transport processes considered are modeled as a system of cyclic concurrent processes sharing common traveling intervals with mutual exclusion. The execution of processes has to guarantee a collision-free and deadlock-free AGVs flow. In this paper, the problem of determination of the rules coordinating access of the vehicles to the shared travel route intervals, ensuring the collision-free and deadlock-free execution of the repetitive processes was reduced to determination of the sufficient conditions assumed to be a pair (an initial state, a set of dispatching rules). In particular, the problem of searching for a pair is defined in the form of the constraint satisfaction problem (CSP) and is solved with the use of the logic programming techniques. The approach proposed provides the framework allowing one to take into account both distinct (pointed) and imprecise (fuzzy) data, in a unified way and treated in a unified form of discrete CSP. The approach considered regards the logic-algebraic method and CP-driven methodology aimed at interactive decision making based on distinct and imprecise data. Illustrative examples are provided.