Qualitative methods in control of industrial production units

The research in this paper deals with the application of qualitative models and statistical methods in quality control of production procedures of various components of industrial press machines. The qualitative simulation of discrete-event machine systems is often based upon the use of qualitative simulation and discrete-event methods techniques too. In order to describe and analyze machine systems and processes in their most efficient way a combination of both advanced qualitative modelling techniques and numerical methods is used. An object-oriented qualitative modelling and simulation toolbox, called QMTOOL, was extended and applied to real industrial machines and processes. The final analysis of the simulation results is accomplished using statistical and mathematical methods and applications for the evaluation of the final machine components as well as the production procedures. The important role of the qualitative modeling methodologies and the reliability of the statistical functions used are documented with practical case studies carried out in a machines constructions company. The results obtained proved that this qualitative modelling approach provided less complex computational models for describing and simulating such machine components.