Motor controller having function of reducing vibration

A motor controller for compensating an elastic deformation between a servomotor and a driven unit driven by the servomotor, comprising:

• a position command unit for commanding the position of the driven unit;
• a compensation filter unit for compensating a position command outputted from the position command unit;
• and
• a servo control unit for controlling the operation of the servomotor based on a compensated position command outputted from the compensation filter unit, wherein
• the compensation filter unit includes:
• an inverse characteristic filter for approximating an inverse characteristic of a transfer characteristic from a motor position to a mechanical position;
• and
• a high frequency cutoff filter for reducing a high frequency component of the position command,
• the inverse characteristic filter is a filter for reducing a gain at a mechanical resonance frequency ω0, and
• the high frequency cutoff filter has a constant “a” times high frequency cutoff frequency aω0 using a constant “a” of 1 or more, with respect to the mechanical resonance frequency ω0 determined in the inverse characteristic filter.