Patent ID: 6903528
Filing Date: 2005-06-07
Classification: G05B,H02P

Abstract:
1. A machine model estimating device of an electric motor control apparatus comprising an electric motor for driving a load machine, a rotation detector for detecting a rotating angle of the electric motor, and a servo control device for controlling the electric motor, comprising a calculating device for outputting an operation command signal for operating the electric motor to the servo control device, and frequency characteristic equations for a rigid body model and an N-inertia model, N being an integer which is equal to or greater than 2 which are previously input to the calculating device, wherein the calculating device includes a frequency characteristic measuring section for measuring a frequency characteristic from the operation command signal and a signal of the rotation detector input from the servo control device to the calculating device, a frequency characteristic peak detecting section for automatically calculating protruded shapes to be a resonance frequency and an anti-resonance frequency from a shape of the frequency characteristic measured by the frequency characteristic measuring section, an attenuation estimation value analyzing section for estimating an attenuation from the resonance frequency and the anti-resonance frequency which are detected by the frequency characteristic peak detecting section, a frequency characteristic error calculating section for calculating errors of the frequency characteristics calculated in the frequency characteristic equation for the N-inertia model and the frequency characteristic equation for the rigid body model from the frequency characteristic obtained by the measurement respectively, and a machine model deciding section for comparing a minimum error of a calculated value of the frequency characteristic of the N-inertia model which is obtained in the frequency characteristic error calculating section and a measured value with a minimum error of a calculated value of the frequency characteristic of the rigid body model and a measured value and deciding, as an actual model, either of the models which has a smaller error.