Abnormality detection device

An abnormality detection device that detects an abnormality of an operation result which is acquired by causing a processor to execute software, the abnormality detection device comprising:

• a divider that acquires a plurality of operation results from a storage device that stores the plurality of operation results and divides the acquired operation results into one or more groups;
• a range setter that sets a normal range of the operation result for each group using a range of data values included in the operation results included in each group;
• and
• an abnormality determiner that acquires a new operation result from the storage device and determines whether the new operation result is normal on the basis of the normal range after the range setter has set the normal range;
• wherein the divider acquires time-series data which is acquired by causing the processor to execute the software in a time series as the plurality of operation results;
• wherein the abnormality detection device further comprises a transition pattern calculator that calculates a transition pattern in which the operation result at each time in the time-series data transitions between the groups;
• and
• wherein the abnormality determiner determines that the new operation result is abnormal when the new operation result is included in the normal range but departs from the transition pattern;
• wherein the abnormality detection device acquires the new operation result as new time-series data which is acquired by causing the processor to execute the software in a time series,
• wherein the transition pattern calculator calculates an occurrence frequency of a new transition pattern in which the new operation result at each time in the new time-series data transitions between the groups for each transition path between the groups, and
• wherein the abnormality determiner determines that the new operation result is abnormal when the occurrence frequency of the new transition pattern is less than a predetermined threshold value at least one of the times and the new operation result is included in the normal range,
• wherein the software has a process of calculating at least one of an intake air amount of an internal combustion engine, a fuel injection amount of the internal combustion engine, and an ignition time of the internal combustion engine as a control command value for controlling the internal combustion engine mounted therein, and
• wherein the divider acquires at least one of the intake air amount, the fuel injection amount, and the ignition time which are calculated by causing the processor to execute the software as the plurality of operation results.