Method and device for identifying rotational inertia of servo system

The invention discloses an identification method and device for rotational inertia of a servo system, and relates to the field of inertia identification. The method comprises the following steps: determining a disturbance observer, inputting a quadrature-axis current of a servo system, a first rotational inertia set for the disturbance observer and a rotating speed of a servo motor in the servo system into the disturbance observer, and obtaining a quadrature-axis current instruction correction value output by the disturbance observer; wherein the quadrature-axis current is a current value under the condition that the inertia ratio of the servo system is smaller than a preset threshold value. And determining the magnitude relationship between the quadrature-axis current and the quadrature-axis current instruction correction value, and determining the rotational inertia of the servo system according to the magnitude relationship and the first rotational inertia. According to the scheme, a specific input instruc