Digital-analog and analog-digital transition card identification method based on equivalent model transform

Abstract

The present invention discloses a method for identifying digital-to-analog (D / A) and analog-to-digital (A / D) conversion cards on the basis of equivalent model conversion, belonging to the technical field of industrial control. The method comprises the steps of: establishing a test platform of the D / A conversion card and the A / D conversion card by adopting Simulink and xPCTarget for performing a series connection test of the D / A conversion card and the A / D conversion card which are connected in series in a semi-physical simulation control system and obtaining accurate input and output test databy using pure digital signal input and storage process; establishing an equivalent model of the D / A conversion card and the A / D conversion card connected in series on the basis of the principle of equivalent model transformation, and identifying the equivalent model by using the input and output test data acquired under the test platform, including obtaining a constant drift and a quantization error of the D / A conversion card and the A / D conversion card by means of curve fitting and normal distribution verification, and obtaining a conversion time delay model on the basis of prediction errorminimization.The method of the present invention improves the performance of the control system by using the equivalent model to replace the D / A conversion card and the A / D conversion card and using an off-line design control algorithm.

Description

technical field [0001] The invention relates to a method for identifying a digital-to-analog and analog-to-digital conversion card in the technical field of industrial control, in particular to a method for identifying a digital-to-analog and analog-to-digital conversion card based on equivalent model transformation. Background technique [0002] In the process of industrial control system design, a semi-physical simulation control system usually includes analog-to-digital conversion card, digital-to-analog conversion card, signal processing board, controller, drive circuit, controlled object and other monitoring units. In order to obtain reliable control performance, mathematical modeling and simulation of semi-physical control systems are required. In system modeling, the analog-to-digital conversion and digital-to-analog conversion parts are often ignored or just considered a gain segment. However, according to the basic principles of digital-to-analog conversion and ana...

AI Technical Summary

Problems solved by technology

Since the time constants in the model are approximate, they often cannot reflect the conversion delay of the actual analog-to-digital conversion and digital-to-analog conversion card, so the accuracy of the model is not very high

Moreover, for multi-channel digital-to-analog conversion cards and analog-to-digital conversion cards, the conversion delay of each channel will be different, and this difference is usually not given in the corresponding manual

In addition, although the literature discusses the causes of quantization errors and gives methods to reduce quantization errors, it does not mention the impact of constant drift

In fact, for digital-to-analog conversion cards and analog-to-digital conversion cards, constant value drift has a greater impact on the stability of the control system than quantization errors. It can not only reduce the performance of the control system, but can even cause the control system to diverge.

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