Motor controller

A controller of a motor that drives a driven body, the controller comprising:

• a command generating unit that generates a movement command for the motor;
• an inertia estimating unit that (i) receives a feedback signal from the motor, the feedback signal including feedback information related to the motor, and iii) estimates an inertia, using the feedback information, on the basis of a predetermined estimation equation, wherein the inertia estimating unit calculates a first estimation result and a second estimation result, the first estimation result being calculated before machining of the driven body is performed, and the second estimation result being calculated after the machining of the driven body is performed;
• a difference computing unit that computes a change in the inertia due to the machining of the driven body, the change in the inertia being computed based on the movement command of the command generating unit;
• and
• a comparing unit that compares (i) a difference between the first estimation result and the second estimation result calculated by the inertia estimating unit, and (ii) the change in the inertia computed by the difference computing unit, wherein
• the estimation equation used by the inertia estimating unit is corrected on the basis of a comparison result of the comparing unit so that the difference between the first estimation result and the second estimation result matches the change in the inertia computed by the difference computing unit.