Controller

1. A controller that controls a servomotor and a spindle motor of a machine tool, a robot, and an industrial machine, comprising:

a control unit, wherein

the control unit includes:

a first correction amount computation unit that computes a first correction amount for correction from a command value to a second command value;

a second correction amount computation unit that computes a second correction amount for correction from the command value to the second command value;

a correction amount selecting unit that selects either one of the first correction amount and the second correction amount,

a correction amount comparing unit that compares the first correction amount computed by the first correction amount computation unit and the second correction amount computed by the second correction amount computation unit;

an abnormality detection unit that detects an abnormality of the first correction amount on the basis of a comparison result obtained by the correction amount comparing unit; and

a stopping unit that determines whether or not a machining process is to be stopped on the basis of a frequency in which an abnormality in the first correction amount is detected by the abnormality detection unit, wherein

the first correction amount computation unit is based on a first mathematical model and parameters of the first mathematical model are determined by machine learning,

the second correction amount computation unit is based on a second mathematical model and parameters of the second mathematical model are determined by a method different from that of the first correction amount computation unit,

an order of the second mathematical model is equal to or lower than an order of the first mathematical model, and

when the abnormality detection unit detects the abnormality, the correction amount selecting unit selects the second correction amount computed by the second correction amount computation unit as a correction amount created from the command value.

2. The controller according to claim 1 , wherein

the abnormality detection unit detects an abnormality when an absolute value of a difference between the first correction amount computed by the first correction amount computation unit and the second correction amount computed by the second correction amount computation unit is equal to or larger than a predetermined value.

3. The controller according to claim 1 , wherein the abnormality detection unit detects an abnormality when an absolute value of a ratio of the first correction amount computed by the first correction amount computation unit to the second correction amount computed by the second correction amount computation unit is equal to or larger than a predetermined value.

4. The controller according to claim 1 , wherein the control unit further includes:

a warning output unit that outputs a warning to the outside of the controller when the abnormality detection unit detects the abnormality.

5. The controller according to claim 1 , wherein the command value is a position command value and the second command value is a speed command value or a current command value.

6. The controller according to claim 1 , wherein the command value is a speed command value and the second command value is a current command value.