Detection method for mismatching of model of closed-loop control system and object

Abstract

The invention discloses a detection method for mismatching of a model of a closed-loop control system and an object. Closed-loop data of the current system is obtained during normal operation of an industrial process. A model quality index is obtained by utilizing the data. The matching degree of the model and the object is detected according to the values of the model quality index. The more the model quality index is approximate to 1, the higher the matching degree of the model and the object is. The model quality index is insusceptible of change of adjusting parameters of the controller and the change of an interference model. By adopting the method, the mismatching of the model and the object can be removed from other elements affecting control performance effectively and influence on the control system performance by the mismatching of the model and the object can be analyzed more clearly. Besides, by adopting the method for detecting the mismatching of the model and the object, no external excitation signals are needed to add during the industrial process in normal operation. The mismatching of the model and the object can be detected in normal operation condition of the industrial process, so that the system maintenance cost is reduced and the system safety is improved.

Description

Technical field [0001] The invention belongs to the technical field of industrial control, and more specifically, relates to a method for detecting mismatch between a model of a closed-loop control system and an object. Background technique [0002] The performance of the closed-loop control system plays a key role in the product quality and system safety of the industrial process. In the past two decades, a large number of scholars have proposed different methods to evaluate the performance of the control system, such as: evaluation with the minimum variance index The performance of the closed-loop control system; the performance of the Linear Quadratic Gaussian (LQG) benchmark rating system; the performance of the generalized Hurst index is used to evaluate the system. [0003] In model-based control technology, the mismatch between the process model and the object is one of the most important factors that reduce the performance of the control system. In the prior art, the follo...

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Problems solved by technology

In the prior art, the following methods are used to detect the mismatch between the model and the object: (1) using partial correlation analysis to detect the mismatch between the model and the object; (2) the method of detecting the mismatch between the model and the object based on the method of subspace ; (3) Using the idea of ​​comments, first express the ratio of the model to the object as a transfer function in the frequency domain, and then use the Bode diagram to detect the mismatch between the model and the object; (4) combine the hypothesis test and the ratio of the model to the object Combined with the transfer function of the model, a set of theory is proposed to detect the mismatch between the model and the object; however, the above methods need to add a certain amount of external excitation to the normal operation of the industrial process, which will inevitably affect the normal operation of the control system

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