A Hysteresis Detection Method Based on Waveform Fitting

Abstract

The invention relates to a waveform fitting based retard detection method, which comprises the following steps: carrying out normalized segmentation and integration on OP (operational) waveforms outputted by a controller so as to calculate a mean value; judging whether a regulating valve has a retard according to the fitting degrees of the calculated mean value and a triangular waveform as well as a sine waveform; if the fitting degree of the calculated mean value and the triangular waveform is high, obtaining a result that the regulating valve has a retard; and if the fitting degree of the calculated mean value and the sine waveform is high, obtaining a result that the loop oscillation is caused by external disturbance. The method disclosed by the invention is convenient to sample, and accords with the operation of actual industrial instruments; a defect of large integral fitting error can be overcome through adopting segmentation fitting, and the retard can be quantized under a certain unit scale standard; and the actual industrial application of the method embodies great operability and promotion / application possibility.

Description

technical field [0001] The invention relates to the technical field of process control, in particular to a hysteresis detection method based on waveform fitting, which is used to detect whether there is hysteresis in a regulating valve and perform quantitative processing on it. Background technique [0002] Oscillation is a common phenomenon in the control loop, and hysteresis is an important cause of control system oscillation, and it is also one of the most common and most difficult problems in control valves. Timely and accurate determination of hysteresis loops is of great significance to ensure high quality and low consumption of products, so the research on valve hysteresis that affects the performance of control loops is of great benefit both in technical applications and in economic benefits. Several mainstream hysteresis detection methods have advantages and disadvantages in the actual industry, and it is difficult to accurately identify and use them. The main probl...

AI Technical Summary

Problems solved by technology

Several mainstream hysteresis detection methods have advantages and disadvantages in the actual industry, and it is difficult to accurately identify and use them. The main problems are as follows:

[0008] The hysteresis detection method of regulating valve based on high-order statistics proposed by Choudhury et al. can use daily operation data to quantify the hysteresis, but this method is more complicated to calculate and requires more mathematical applications. In addition, due to the OP-PV diagram generated by its signal Sensitive to some parameters, it is easy to affect the accuracy of the results

[0009] It is precisely because of the limitations of hysteresis detection methods that it is difficult to achieve satisfactory detection quality with existing detection methods.

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