Frequency spectrum analyzing method and device of control object

Abstract

The invention provides a frequency spectrum analyzing method of a control object, comprising the following steps: presetting the resistance of an inductance-capacitance-resistance (LCR) oscillating circuit, wherein the value of the resistance is more than -2 and less than 0; obtaining the input signal of the system control object, and obtaining the output signal of the system control object; inputting the input signal to the LCR oscillating circuit, obtaining the first response signal after performing the convergence treatment; inputting the output signal to the LCR oscillating circuit, obtaining the second response signal after performing the convergence treatment; comparing the first response signal with the second response signal to obtain the spectrum analysis result of the system control object. The invention further puts forward a spectrum analysis device of the control object. The anti-interference ability of the system is improved, and the reliability of the frequency spectrum analysis is improved.

Description

technical field [0001] The invention relates to the field of industrial automatic control, in particular to a spectrum analysis method and device for a control object. Background technique [0002] The frequency characteristic of the system control object is the fundamental basis for the control system design and parameter adjustment. The basic principle of frequency characteristic identification is: under the action of the excitation signal, the system control object obtains the frequency spectrum characteristics of the system or object input signal and output signal in the frequency domain through the frequency spectrum identification method, mainly including: amplitude spectrum characteristics, phase spectrum characteristics, etc. . [0003] But the process signal of the industrial process system is generally interfered by various internal and external random noises, and the noise interference has a non-negligible impact on the identification of the frequency characteris...

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Problems solved by technology

[0003] However, the process signal of the industrial process system is generally interfered by various internal and external random noises, and the noise interference has a non-negligible impact on the frequency characteristic identification of the process control system.

[0004] From the perspective of system frequency characteristic identification, most process objects have characteristics similar to low-pass filters. After the excitation signal passes through the object, relatively high-frequency signals outside the low-pass cutoff frequency of the object will have a large attenuation. Especially when there is high-intensity noise interference at the output of the system control object, the noise-to-signal ratio characteristics of these relatively high-frequency signals will be significantly deteriorated, and the frequency characteristic identification quality of the system control object at these relatively high frequencies is usually difficult to guarantee. of

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