Modeling of the behavior of an integrated industrial system during a catastrophe

Abstract

Lines and groups of equipment including robots are recognized as the basic level of the Integrated Industrial System, IIS. The management system is considered as a high level of the IIS which is controlled with a Hierarchical Numerical Control, system HNC. Metallurgical objects, in particular sand foundries are taken into consideration. The evaluation criterion of a catastrophe course is the speed of the decrease in the IIS reliability (R) in the crash time period ( τ cr): V R = dR/dτ cr . If failures appear, then V R≈0 and the system structures tolerates the failures. If the failures increase, the threshold tolerance is crossed, and V R will increase as well. V R assumes low values for the soft degradation of the IIS system, while V R → ∞for the crash degradation. The course of catastrophe can be simulated by testing the IIS system model. Simulating testing of the IIS takes into consideration the transformation of reliability structure under the influence of load changes. This process determines the behavior of the system during a catastrophe. The basis for determining the transformation is the construction of a formula for a generalized reliability connection. The generalized reliability connection is characteristic for reactions of the soft degradation type. During a catastrophe caused by system load growth and decreasing reserves, there occurs an IIS structure transformation in the following sequence: • -parallel multibranch reserving with multiple reserve, • -parallel singlebranch reserving with full reserve, • -parallel with partial reserve, • -series. If one element is damaged after the final stage transformation (for the series structure), the IIS system will be crashed. Evaluation of the course of a catastrophe of the IIS system allows: (1) the correct decisions for the prevention of the catastrophe, (2) the design of the fault tolerance system architecture when V R ≈0.