Autotune Identification under Load Disturbance

Shen, Shing Chuan; Wu, Jiun-Sheng; Yu, Cheng‐Ching

doi:10.1021/ie950480g

Cited by 59 publications

(22 citation statements)

References 13 publications

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“…Recently, a two‐channel relay has been proposed to obtain a Nyquist point information corresponding to a given phase angle 10, 11. Methods to reject unknown load disturbances and restore symmetric relay oscillations have been available 12–14. A biased relay has been used to obtain the process steady state gain as well as the ultimate information from only one relay test 15.…”

Section: Introductionmentioning

confidence: 99%

Integrals of relay feedback responses for extracting process information

Lee¹,

Sung²,

Edgar³

2007

AIChE Journal

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in Wiley InterScience (www.interscience.wiley.com).Relay feedback methods have been widely used in tuning proportional-integral-derivative controllers automatically. Previous approaches usually use specific point data such as the oscillation amplitude and period of the relay response. In this article, we propose new identification methods, which use integrals of the relay response instead of the point data. The proposed methods guarantee better accuracy and advantages in obtaining the ultimate information of process as well as parametric models compared with previous approaches, because effects of the high order harmonic terms are suppressed significantly using the integrals of the relay responses.

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Section: Introductionmentioning

confidence: 99%

Integrals of relay feedback responses for extracting process information

Lee¹,

Sung²,

Edgar³

2007

AIChE Journal

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“…When slow drift is added to the process output, the relay oscillation is asymmetric (Figure 1). The ultimate data estimated from the asymmetric oscillation can have relative errors over 20% 12. Iterative methods to restore symmetric responses for constant bias by compensating it with the input or output bias iteratively are available 13.…”

Section: Relay Feedback Methods Under Drifts and Noisy Environmentsmentioning

confidence: 99%

“…Now many variations and applications have been reported for autotuning of PID controllers 2–4. They include methods to obtain more accurate ultimate information by suppressing the higher harmonic terms,4–8 methods to obtain Nyquist points other than the critical point,2, 5, 9–11 methods to reject unknown load disturbances and restore symmetric relay oscillations,10–14 and methods to obtain the process steady state gain as well as the ultimate information 15, 16. Recently, Lee et al17 proposed identification methods to extract more accurate frequency response information and parametric models from a single conventional relay feedback test.…”

Section: Introductionmentioning

confidence: 99%

Relay feedback identification for processes under drift and noisy environments

et al. 2010

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in Wiley Online Library (wileyonlinelibrary.com).Relay feedback identification methods are widely used to find the process ultimate information and tune proportional-integral-derivative controllers. The conventional relay feedback method has several disadvantages, which include poor estimates of the process ultimate information for low-order processes, chattering of relay for noisy environments, and asymmetric relay responses for constant biases or slow drifts in the process outputs. Methods to mitigate each of the above disadvantages are available. However, a systematic method to treat all of them has not been studied yet. Here, simple relay feedback methods that resolve these problems by introducing band-pass filters in the feedback loop are proposed. The high-pass filter part in band-pass filter removes a constant bias or low frequency drift, and the low-pass filter part removes high frequency noise and high-order harmonic terms in the relay feedback oscillation, resulting better estimates of the process ultimate information. Because filters used for the proposed methods are able to reject constant biases, the process steady state gains can be estimated without disturbing the relay feedback oscillations and first order plus time delay (FOPTD) models can be obtained by combining the process steady state gains with the relay oscillation information. V V C

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“…There is not necessary to bias the relay reference value to compensate the static disturbance, which does not have to be known in advance (see e.g. [21], [22], [23]). The FOPDT system output compared to its IPDT approximation is shown in Figs.…”

Section: Fopdt Controlmentioning

confidence: 99%

Intelligent P controller and disturbance observer based PI controller comparison

Ťapák

Huba

2015

2015 20th International Conference on Process Control (PC)

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The paper shows analogies between two separately evolved areas of PID control, the disturbance observer based controllers and the "intelligent" PID controllers. The simplest "intelligent" PID controller is represented by the "intelligent P" controller denoted as iP. It is designed for the simplified "ultra-local" integral plant models neglecting all internal plant feedbacks. These are included and compensated by an equivalent input disturbance. The performance of the iP controller is compared with the controllers employing disturbance observers based on inverted plant model. It is shown that both these solutions may represent an alternatives to the same control strategy.

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Autotune Identification under Load Disturbance

Cited by 59 publications

References 13 publications

Integrals of relay feedback responses for extracting process information

Integrals of relay feedback responses for extracting process information

Relay feedback identification for processes under drift and noisy environments

Intelligent P controller and disturbance observer based PI controller comparison

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