Manufacturing machinery may have flaws that can cause a
significant reduction in efficiency and lifespan, negatively
affecting production, equipment operations and maintenance
costs. Incorporating continuous monitoring inspections into
condition-based maintenance strategy will ensure that
equipment is operating as designed. Condition monitoring is a
component of predictive maintenance activities. Condition
monitoring allows in preventing breakdowns, helps to avoid
unplanned shutdowns and enables to optimize maintenance
resources by scheduling maintenance as needed based on
analysis of asset condition data. All of these activities help to
predict potential equipment failures before they occur.
Condition based maintenance is a decision-making strategy
based on real-time diagnosis of impending failures and
prognosis of future equipment health [15]. To provide optimal
decision making on when to take equipment down for
maintenance should be integrated with overall manufacturing
operations. This is why additional information about sensing
and data acquisition is needed. The accurate data for available
signals from the equipment are to be collected. The signals are
captured by using specific sensors. The condition monitoring
and establishing of health assessment is a baseline for
equipment performance as critical step in enabling predictive
maintenance solutions. Standard condition monitoring
techniques like statistical process control or advanced process
control could be employed primarily in process monitoring.
Going forward, health assessment and prognostics is
considered as one of the key challenges in enabling
predictive/preventive maintenance solutions. The mathematical
algorithms complexity to infer impending failure requires
artificial intelligence to get the solutions. That is why
manufacturing sites create challenges for integrated optimal
predictive maintenance solutions. Integration of data from
multiple sources is needed to be included in the final decision.
The choice of maintenance alternative is a complex and
difficult decision making problem. A maintenance program
needs to define different maintenance alternative for different
equipments. Therefore, the maintenance problem could be
recognizing as a combinatorial optimization problem. When
considering a decision making problem it should be noted that
in all cases there exists a decision-maker. Another prerequisite
is that the optimal solution implies the existence of a function,
which should be optimized.
Let x be a vector containing p decision variables. An
optimization problem can be stated as: