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T. Nagahata et al.
23.3 Concept of Maintenance Action Proposal by Part
Agent
The flow to propose the maintenance action by the part agent is shown in Fig. 23.2.
Using the system developed by Takata (2006), a method for generating the deterioration process is proposed (the detailed description is presented in Sect. 23.4).
First, the deterioration mechanisms caused by the deterioration factors are registered
in the database. The deterioration database is searched on the basis of the environmental and operating conditions assumed for the part. A deterioration mechanism
caused by the deterioration factors is specified. A deterioration process is created
by linking multiple identified deterioration mechanisms. For the created process,
the conditional probability is calculated based on the environment and conditions
under which the product is used. A causality model is created from the deterioration
process. A Bayesian estimation is performed based on the causality model, and the
probability of product deterioration is obtained. The transition probability between
stages of the life cycle model is estimated based on this deterioration probability,
and the expectation value of the next stage is calculated (the detailed LCS methods
are described in Sect. 23.7).
By using this method, a part agent proposes the maintenance action by using
a Bayesian estimation, which estimates the probability of occurrence of the cause
event from the observed facts.
23.4 Creating Deterioration Processes
This section describes the deterioration analysis system. The factors that cause the
deterioration of parts are influenced by the operating conditions, environmental
conditions, and product models. The existence of factors of deterioration is judged
by examining these conditions. The deterioration can be classified into the following
two categories:
• Deterioration factors
• Factors that cause deterioration, such as high temperatures, large loads, and
prolonged use
• Deterioration mechanism
• Effects on parts caused by the deterioration factors, such as fatigue, fracture, and
corrosion.
The deterioration process is created by linking the degradation factor with the
degradation mechanism. Figure 23.3 shows an example of the deterioration process
in the general corrosion of parts. In this figure, the deterioration factor is represented
by a square and the deterioration mechanism is represented by an ellipse. “Water” and
“Chloride ion” become deterioration factors, and cause “Wet corrosion,” which is a
deterioration mechanism. The “Wet corrosion” generated by this process becomes a
T. Nagahata et al.
23.3 Concept of Maintenance Action Proposal by Part
Agent
The flow to propose the maintenance action by the part agent is shown in Fig. 23.2.
Using the system developed by Takata (2006), a method for generating the deterioration process is proposed (the detailed description is presented in Sect. 23.4).
First, the deterioration mechanisms caused by the deterioration factors are registered
in the database. The deterioration database is searched on the basis of the environmental and operating conditions assumed for the part. A deterioration mechanism
caused by the deterioration factors is specified. A deterioration process is created
by linking multiple identified deterioration mechanisms. For the created process,
the conditional probability is calculated based on the environment and conditions
under which the product is used. A causality model is created from the deterioration
process. A Bayesian estimation is performed based on the causality model, and the
probability of product deterioration is obtained. The transition probability between
stages of the life cycle model is estimated based on this deterioration probability,
and the expectation value of the next stage is calculated (the detailed LCS methods
are described in Sect. 23.7).
By using this method, a part agent proposes the maintenance action by using
a Bayesian estimation, which estimates the probability of occurrence of the cause
event from the observed facts.
23.4 Creating Deterioration Processes
This section describes the deterioration analysis system. The factors that cause the
deterioration of parts are influenced by the operating conditions, environmental
conditions, and product models. The existence of factors of deterioration is judged
by examining these conditions. The deterioration can be classified into the following
two categories:
• Deterioration factors
• Factors that cause deterioration, such as high temperatures, large loads, and
prolonged use
• Deterioration mechanism
• Effects on parts caused by the deterioration factors, such as fatigue, fracture, and
corrosion.
The deterioration process is created by linking the degradation factor with the
degradation mechanism. Figure 23.3 shows an example of the deterioration process
in the general corrosion of parts. In this figure, the deterioration factor is represented
by a square and the deterioration mechanism is represented by an ellipse. “Water” and
“Chloride ion” become deterioration factors, and cause “Wet corrosion,” which is a
deterioration mechanism. The “Wet corrosion” generated by this process becomes a