scholarly journals Iterative Method for Tuning Multiloop PID Controllers Based on Single Loop Robustness Specifications in the Frequency Domain

Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 140
Author(s):  
Juan Garrido ◽  
Mario L. Ruz ◽  
Fernando Morilla ◽  
Francisco Vázquez
Keyword(s):  
Frequency Domain ◽  
Open Loop ◽  
The Other ◽  
Pid Controllers ◽  
Single Input Single Output ◽  
Tuning Method ◽  
Pid Tuning ◽  
Single Output ◽  
Gain Margin ◽  
Single Input

Multiloop proportional-integral-derivative (PID) controllers are widely used for controlling multivariable processes due to their understandability, simplicity and other practical advantages. The main difficulty of the methodologies using this approach is the fact that the controllers of different loops interact each other. Thus, the knowledge of the controllers in the other loops is necessary for the evaluation of one loop. This work proposes an iterative design methodology of multiloop PID controllers for stable multivariable systems. The controllers in each step are tuned using single-input single-output (SISO) methods for the corresponding effective open loop process (EOP), which considers the interaction of the other loops closed with the controllers of the previous step. The methodology uses a frequency response matrix representation of the system to avoid process approximations in the case of elements with time delays or complicated EOPs. Consequently, different robustness margins on the frequency domain are proposed as specifications: phase margin, gain margin, phase and gain margin combination, sensitivity margin and linear margin. For each case, a PID tuning method is described and detailed for the iterative methodology. The proposals are exemplified with two simulations systems where the obtained performance is similar or better than that achieved by other authors.

scholarly journals Establishing the torsional rigidity of a rotation module responsible for the flexion-extension motions of the elbow

2018 ◽  
Vol 178 ◽  
pp. 07006
Author(s):  
Tudor Deaconescu ◽  
Andrea Deaconescu
Keyword(s):  
Rotation Angle ◽  
Torsional Rigidity ◽  
The Other ◽  
Single Input Single Output ◽  
Single Output ◽  
Equilibrium Angle ◽  
Pneumatic Muscles ◽  
Flexion Extension ◽  
Single Input

The paper presents and discusses a system devised for the mobilisation of the elbow including a pair of agonist-antagonist pneumatic muscles aimed mainly at ensuring the accuracy of the rotation angle. This system is of SISO type (single input - single output) with the variable Δp (the pressure by that one of the muscles is charged symmetrically in the detriment of the other) as its input value. Further discussed are the dependency of the equilibrium angle on Δp and the possibility of controlling the torsional rigidity by adjusting the sum of the feed pressures.

scholarly journals Passivity based Approach for the Level Control of Spherical Tank Process

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Priya C ◽  
Lakshmi Ponnnusamy
Keyword(s):  
Real Time ◽  
Open Loop ◽  
Level Control ◽  
Time Model ◽  
Single Input Single Output ◽  
The Real ◽  
Single Output ◽  
Spherical Tank ◽  
Tank System ◽  
Single Input

The aim of this paper is to obtain the mathematical model and the real time model of the Single Input Single Output (SISO) conical tank system. The experimental model is obtained from the open loop response in real time and the transfer function is obtained using the two point method. For the real time model, two different controllers namely Zeigler Nichols tuned PI controller and passivity based controller are designed and tested in simulation and the performance of both the controllers are tested for servo operation and regulatory operation. The designed controllers are tested in Simulation and the response is recorded. The simulation results shows that the Passivity based Controller works better for the spherical tank process.

Measurement Errors in Closed-Loop Frequency Response Estimates

1980 ◽  
Vol 102 (1) ◽  
pp. 13-20
Author(s):  
P. W. Davall ◽  
P. N. Nikiforuk
Keyword(s):  
Frequency Response ◽  
Measurement Errors ◽  
Closed Loop ◽  
Power Spectra ◽  
Open Loop ◽  
Feedback Signal ◽  
Single Input Single Output ◽  
Closed Loop Systems ◽  
Single Output ◽  
Single Input

The sampling distributions associated with frequency response estimates of single input, single output closed-loop systems are derived for the case where both the output and feedback signal measurements are subject to added noise. This work is an extension of that done by Goodman [1-3] and Akaike [4, 5] on open-loop systems. Conditions for response estimate bias are investigated and approximate distributions for the power spectra estimates of the added noise terms are derived.

scholarly journals Parametric Robust Control of the Multivariable 2 × 2 Looper System in Steel Hot Rolling: A Comparison between Multivariable QFT and H∞

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 839 ◽  
Author(s):  
Luis F. Cantú ◽  
Pedro Mendiola ◽  
Álvaro A. Domínguez ◽  
Alberto Cavazos
Keyword(s):  
Frequency Domain ◽  
Hot Rolling ◽  
Performance Indicators ◽  
Single Input Single Output ◽  
Single Output ◽  
Stability Robustness ◽  
Higher Power ◽  
Single Input ◽  
Hot Rolling Mill ◽  
Looper System

Two robust mutlivariable controllers, H∞ and a decentralized quantitative feedback theory (QFT), are designed in the frequency domain for the 2 × 2 looper system in a steel hot rolling mill to keep stability in the presence of parametric uncertainties. The H∞ controller is designed by using the mixed sensitivity approach, while the multivariable decentralized QFT is designed by the extension of the sequential loop closing method presented elsewhere. Stability robustness conditions are verified in the frequency domain, while simulations in time domain are carried out to evaluate the controllers and compare their performance along with that of proportional + integral (PI) and single input single output (SISO) QFT controllers designed earlier. The QFT controller shows the best balance among the performance indicators analyzed here; however, at the expenses of using higher power in one of the control inputs.

scholarly journals Performance Evaluation of the Good Gain Method Against Other Methods Using a Water Level Control System

2020 ◽  
Vol 14 ◽  
Keyword(s):  
Water Level ◽  
Pid Controller ◽  
The Other ◽  
Pid Controllers ◽  
Proportional Integral Derivative ◽  
Level Control ◽  
Tuning Method ◽  
Pid Tuning ◽  
Pid Controller Tuning ◽  
Tuning Methods

Various tuning methods have been proposed for proportional-integral-derivative (PID) controller. A respectively new and simple experimental method for tuning PID controllers named a Good Gain method that was recently proposed by F. Haugen in 2010, this method is not yet recognized among the other known methods for tuning. However, the founder of this methods claims that it can be an alternative to the famous Ziegler-Nichols. In this paper, PID tuning method has been performed experimentally using a real water level system in order to test and validates the Good Gain method. Also other PID tuning methods applied to the same system to compare the results. The results show that the Good Gain method gives an acceptable stability and response comparing to the other industrial PID controller tuning procedures

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