Models for fault tolerance in manufacturing systems

Abstract

The field of fault tolerance in computer science and engineering has been thoroughly investigated over a long period of time. A great number of different approaches have been presented on means for improving fault tolerance under certain error conditions in computerized systems. One important area that has introduced computers in order to enhance productivity, flexibility and economy, is manufacturing systems in order to acquire computer-integrated manufacturing (CIM). Using computers in a manufacturing system introduces new sources of difficulties, as well as providing new possibilities for overcoming erroneous situations that might disturb production. The aim of this paper is to describe how the use of different configurations for a manufacturing system can improve fault tolerance. One specific erroneous situation which may occur in CIM is the partitioning of a network. This situation can be handled satisfactorily by using the suggested manufacturing system configurations. Additional improvements to fault tolerance can be achieved through the introduction of data buffers and material buffers. This approach is described in this paper.

Fault tolerance in partitioned manufacturing networks

“…In,cache In,all FT denote a specific task to be performed by a production unit (n is the same as a mission in [2,5]), denote the information about n that is intended to be retrieved via the data network, denote the information about n that is intended to be retrieved via the material network, denote the information about n that is intended to be present in the cache, denote all the necessary information as described in Section 2.2, denote that the system is fault tolerant because of the redundant transmission of information or because the necessary information is already present in the cache. Ip,cache(t) Pp,n(t) denote the information that can be retrieved by a production unit p via the data network at time t within time-limit At (At = predefined time-out), denote the information that can be retrieved by a production unit p via the material network at time t within time-limit At (at = predefined time-out), denote the information that is present in the cache in production unit p at time t, denote that the production of n can continue in production unit p before t + At expires.…”

Dependability in distributed computerized manufacturing systems

“…This section describes how configuration can be performed by using three different methods of dynamic configuration [4]. Three different types of configuration are defined for the GRS structure.…”