Numerical control device having function of calculating frequency characteristic of control loop

A numerical control device which controls at least one control object, the numerical control device comprising:

• a sine wave generation part which generates a sinusoidal signal;
• a control loop excitation part which inputs the sinusoidal signal which is output from said sine wave generation part to a control loop of said control object;
• a data acquisition part which samples an input signal which is input to said control loop and an output signal which said control object outputs at a certain period;
• a frequency characteristic calculation part which uses the sampling data of the input signal and output signal to calculate the frequency characteristic of said control loop;
• and
• a phase shift part which shifts the phase of said sinusoidal signal,
• wherein the numerical control device is configured to
• perform an analysis of the frequency characteristic of the control loop calculated by the frequency characteristic calculation part, and
• adjust parameters of the control loop based on a result of the analysis to control the control object, and
• wherein the numerical control device is configured to obtain the sampling data of different phases on the sinusoidal signal by inputting
• a base sinusoidal signal having, at a frequency, an initial phase and
• at least one phase-shifted sinusoidal signal having, at said frequency, a phase shifted from the initial phase by a certain amount respectively, into said control loop a plurality of times to enable said frequency characteristic calculation part to calculate the frequency characteristic of said control loop.