Motor control device and motor control method

1. A motor control device configured to feedback-control state quantity of a motor or a mechanical load, the device comprising:

a first notch filter disposed inside a feedback control system and configured to change a frequency component to be removed;

a first notch controller configured to change a first notch frequency as a center frequency of the first notch filter; and

a change forecaster configured to calculate to output, in accordance with the first notch frequency at each of a plurality of past times, at least one of a forecast value of the notch frequency at a specific future time, a forecast value of elapsed time from current time until the notch frequency is to become out of a specific frequency range, and a forecast value of time when the notch frequency is to become out of the specific frequency range.

2. The motor control device according to claim 1 , wherein the change forecaster calculates the forecast value by extrapolation calculation according to a linear function, from the first notch frequency at each of the plurality of past times.

3. The motor control device according to claim 1 , wherein the first notch controller changes the first notch frequency only within a preset notch frequency range.

4. The motor control device according to claim 3 , wherein the first notch frequency of the first notch filter is set not to overlap with a control band of the feedback control system.

5. The motor control device according to claim 1 , further comprising a notch frequency output unit configured to sample the first notch frequency changed by the first notch controller,

wherein the change forecaster calculates the forecast value from the sampled notch frequency.

6. The motor control device according to claim 1 , further comprising:

a second notch filter disposed inside the feedback control system and configured to change a frequency component to be removed; and

a second notch controller configured to change a second notch frequency as a center frequency of the second notch filter,

wherein

the first notch filter and the second notch filter are connected in series, and

the change forecaster calculates the forecast value for each of the first notch controller and the second notch controller.

7. The motor control device according to claim 6 , wherein

when calculating a plurality of forecast values of elapsed time, the change forecaster outputs the forecast value of shortest elapsed time, and

when calculating a plurality of forecast values of times, the change forecaster outputs the forecast value of an earliest time.

8. A motor control method of feedback-controlling state quantity of a motor or a mechanical load, the method comprising:

a notch control step of changing a notch frequency as a center frequency of a notch filter disposed inside a feedback control system and configured to change a frequency component to be removed; and

a change forecasting step of calculating to output, in accordance with a notch frequency at each of a plurality of past times, at least one of a forecast value of the notch frequency at a specific future time, a forecast value of elapsed time from current time until the notch frequency is to become out of a specific frequency range, and a forecast value of time when the notch frequency is to become out of the specific frequency range.