On the Development and Implementation of a Matrix-Based Discrete Event Controller

A supervisory controller for Discrete Event (DE) Systems is presented that uses a novel Matrix Formulation. This matrix formulation makes it direct to write down the DE controller from standard manufacturing tools such as the Bill of Materials or the assembly tree. The matrices also make it straightforward to actually implement the DE controller on a manufacturing workcell for sequencing the jobs and assigning the resources. It is shown that the DE controller equations plus the Petri Net marking transition equation together provide a complete dynamical description of a DE system. So that a computer simulation can be performed to check the DE performance of the controller before it is implemented. In this paper, we implement the DE controller on an actual three-robot Intelligent Material Handling (IMH) cell at the Automation and Robotics Research Institute (ARRI) of UTArlington. The versatility of the system developed with this DE controller permits implementing different methodologies for conflict resolution, as well as optimization of the resource assignment and part throughput. Technical information and comparison results between the development of the controller in LabVIEW and its simulation using MATLAB are provided.