Supervisory control of flowlines by modelling the legal language as inequalities

A method for modelling the class of discrete-event systems that characterise flowlines is developed. The legal languages are modelled as a set of inequalities, which effectively reduces the amount of memory needed for implementing the resulting supervisors, called inequality supervisors. An example demonstrates that the use of inequality supervisors can lead to an implementation where the memory usage is significantly reduced compared to both centralised and modular supervisors. In this way, the state-space explosion is mitigated by the approach presented here. Furthermore, the approach indicates that the solution can be implemented in a distributed control architecture utilising DES concepts such as nonconflicting and nonblocking