Patent ID: 7956568

Claim:
A servo motor controller having automatic gain adjustment function for adjusting a velocity control gain, comprising: a velocity control section that calculates a torque instruction value by multiplying a velocity deviation which is a difference between a velocity instruction value and a velocity detection value by said velocity control gain which is a product of an operation constant and an adjustment magnification factor which has been set in advance for adjusting said operation constant; a disturbance addition section that adds a torque disturbance at a specified frequency to said torque instruction value; an input/output characteristic estimation section that estimates an input/output gain and a phase lag with said torque disturbance as an input value to a control system and with said torque instruction value as an output value from said control system; a frequency identification section that performs analysis based on a frequency response method and identifies a frequency of said torque disturbance exhibiting a specified phase lag; an input/output gain identification section that identifies an input/output gain at said frequency identified by said frequency identification section; and a magnification factor resetting section that resets said adjustment magnification factor by multiplying said adjustment magnification factor by a value obtained by multiplying a specified correction coefficient that is less than 1 to a ratio between said identified input/output gain and said specified target value of said input/output gain.