Plan generation apparatus, method and computer readable medium for multi-process production of intermediate product

1. A plan generation apparatus that generates a process plan of a product to be produced via a plurality of processes, the plan generation apparatus comprising

processing circuitry to:

define a first apparatus as one apparatus among a plurality of apparatuses, each apparatus of the plurality of apparatuses that belongs to one of the plurality of processes,

define a first quality value as a quality value indicating a quality of an intermediate product processed by the first apparatus,

define a second apparatus as an apparatus among the plurality of apparatuses that belongs to a process prior to the process to which the first apparatus belongs,

define a second quality value as a quality value of an intermediate product processed by the second apparatus, and

determine whether correlation exists between the first quality value and the second quality value;

determine, using a quality reference value indicating a reference value for quality of the intermediate product, whether the first apparatus and the second apparatus are a set of apparatuses for which a first error between the first quality value and the quality reference value and a second error between the second quality value and the quality reference value cancel each other out when it is determined that correlation exists between the first quality value and the second quality value; and

generate the process plan using the set of apparatuses when it is determined that the first apparatus and the second apparatus are the set of apparatuses.

2. The plan generation apparatus according to claim 1 , wherein the processing circuitry

determines that the first apparatus and the second apparatus are the set of apparatuses when a negative correlation exists between the first quality value and the second quality value and, also, positives/negatives of the first error and the second error are identical, and

determines that the first apparatus and the second apparatus are the set of apparatuses when a positive correlation exists between the first quality value and the second quality value and, also, positives/negatives of the first error and the second error are different.

3. The plan generation apparatus according to claim 1 , wherein the processing circuitry

calculates a correlation coefficient between the first quality value and the second quality value as a first correlation coefficient, and

determines whether correlation exists between the first quality value and the second quality value on the basis of the first correlation coefficient.

4. The plan generation apparatus according to claim 1 , wherein the processing circuitry

detects, as a third apparatus, an apparatus having correlation with the second apparatus and also having correlation with the first apparatus among apparatuses belonging to processes prior to the process to which the second apparatus belongs,

defines a third quality value as a quality value of the third apparatus,

calculates a partial correlation coefficient on the basis of a second correlation coefficient and a third correlation coefficient, the second correlation coefficient being a correlation coefficient between the third quality value and the second quality value and the third correlation coefficient being a correlation coefficient between the third quality value and the first quality value, and

determines whether correlation exists between the first quality value and the second quality value on the basis of the partial correlation coefficient that was calculated.

5. The plan generation apparatus according to claim 1 , wherein the processing circuitry

calculates an average value of the quality value of each apparatus of the plurality of apparatuses on the basis of quality information including the quality value of the intermediate product processed by each apparatus of the plurality of apparatuses, and determines whether a difference between a current quality value of each apparatus of the plurality of apparatuses and the average value is greater than a threshold value, and

defines, as a determination apparatus, an apparatus for which the difference was determined to be greater than the threshold,

selects, from a process to which the determination apparatus belongs, an apparatus having a quality value for which the difference between the quality value and the average value is less than or equal to the threshold value as a switching apparatus, and

switches a path from the determination apparatus to the switching apparatus.

6. A plan generation method of a plan generation apparatus that generates a process plan of a product to be produced via a plurality of processes, the plan generation method comprising:

defining a first apparatus as one apparatus among a plurality of apparatuses, each apparatus of the plurality of apparatuses that belongs to one of the plurality of processes,

defining a first quality value as a quality value indicating a quality of an intermediate product processed by the first apparatus,

defining a second apparatus as an apparatus among the plurality of apparatuses that belongs to a process prior to the process to which the first apparatus belongs,

defining a second quality value as a quality value of an intermediate product processed by the second apparatus, and

determining whether correlation exists between the first quality value and the second quality value;

determining, using a quality reference value indicating a reference value of quality of the intermediate product, whether the first apparatus and the second apparatus are a set of apparatuses for which a first error between the first quality value and the quality reference value and a second error between the second quality value and the quality reference value cancel each other out when it is determined that correlation exists between the first quality value and the second quality value; and

generating the process plan using the set of apparatuses when it is determined that the first apparatus and the second apparatus are the set of apparatuses.

7. A non-transitory computer readable medium storing a plan generation program of a plan generation apparatus that generates a process plan of a product to be produced via a plurality of processes, the plan generation program being configured to cause a computer to execute:

correlation determination processing to

define a first apparatus as one apparatus among a plurality of apparatuses, each apparatus of the plurality of apparatuses that belongs to one of the plurality of processes,

define a first quality value as a quality value indicating a quality of an intermediate product processed by the first apparatus,

define a second apparatus as an apparatus among the plurality of apparatuses that belongs to a process prior to the process to which the first apparatus belongs,

define a second quality value as a quality value of an intermediate product processed by the second apparatus, and

determine whether correlation exists between the first quality value and the second quality value;

set determination processing to determine, using a quality reference value indicating a reference value of quality of the intermediate product, whether the first apparatus and the second apparatus are a set of apparatuses for which a first error between the first quality value and the quality reference value and a second error between the second quality value and the quality reference value cancel each other out when it is determined that correlation exists between the first quality value and the second quality value; and

process plan generation processing to generate the process plan using the set of apparatuses when it is determined that the first apparatus and the second apparatus are the set of apparatuses.

8. The plan generation apparatus according to claim 2 , wherein the processing circuitry

calculates a correlation coefficient between the first quality value and the second quality value as a first correlation coefficient, and

determines whether correlation exists between the first quality value and the second quality value on the basis of the first correlation coefficient.

9. The plan generation apparatus according to claim 2 , wherein the processing circuitry

calculates an average value of the quality value of each apparatus of the plurality of apparatuses on the basis of quality information including the quality value of the intermediate product processed by each apparatus of the plurality of apparatuses, and determines whether a difference between a current quality value of each apparatus of the plurality of apparatuses and the average value is greater than a threshold value, and

defines, as a determination apparatus, an apparatus for which the difference was determined to be greater than the threshold,

selects, from a process to which the determination apparatus belongs, an apparatus having a quality value for which the difference between the quality value and the average value is less than or equal to the threshold value as a switching apparatus, and

switches a path from the determination apparatus to the switching apparatus.

10. The plan generation apparatus according to claim 3 , wherein the processing circuitry

calculates an average value of the quality value of each apparatus of the plurality of apparatuses on the basis of quality information including the quality value of the intermediate product processed by each apparatus of the plurality of apparatuses, and determines whether a difference between a current quality value of each apparatus of the plurality of apparatuses and the average value is greater than a threshold value, and

defines, as a determination apparatus, an apparatus for which the difference was determined to be greater than the threshold,

selects, from a process to which the determination apparatus belongs, an apparatus having a quality value for which the difference between the quality value and the average value is less than or equal to the threshold value as a switching apparatus, and

switches a path from the determination apparatus to the switching apparatus.

11. The plan generation apparatus according to claim 4 , wherein the processing circuitry

calculates an average value of the quality value of each apparatus of the plurality of apparatuses on the basis of quality information including the quality value of the intermediate product processed by each apparatus of the plurality of apparatuses, and determines whether a difference between a current quality value of each apparatus of the plurality of apparatuses and the average value is greater than a threshold value, and

defines, as a determination apparatus, an apparatus for which the difference was determined to be greater than the threshold,

selects, from a process to which the determination apparatus belongs, an apparatus having a quality value for which the difference between the quality value and the average value is less than or equal to the threshold value as a switching apparatus, and

switches a path from the determination apparatus to the switching apparatus.