Loop‐Shaping Design Of Pid Controllers With Constant Ti/Td RATIO

Wallén, Anders; Åström, Karl Johan; Hägglund, Tore

doi:10.1111/j.1934-6093.2002.tb00080.x

Cited by 32 publications

(19 citation statements)

References 6 publications

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“…In the MIGO design the edges are avoided by restricting the derivative gain. Other attempts to constrain the controller have also been proposed, the derivative gain has been restricted to the largest gain of a PD controller that maximizes proportional gain [1] and the constraint T i = 4T d is proposed in [19]. When using convex-concave optimization the problem can be avoided by introducing a curvature constraint on the loop transfer function.…”

Section: Example 4 Nyquist Plots With Kinksmentioning

confidence: 99%

PID design by convex-concave optimization

Hast

Åström

Bernhardsson

et al. 2013

2013 European Control Conference (ECC)

103

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Section: Example 4 Nyquist Plots With Kinksmentioning

confidence: 99%

PID design by convex-concave optimization

Hast

Åström

Bernhardsson

et al. 2013

2013 European Control Conference (ECC)

103

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“…A third relation between T i and T d is proposed by Wallen et al, [8] as T i =αT d . The stability and performance of the system are heavily depends on α. Astrom and Hagglund [1] proposed a method namely MZN, in which the value of α is selected as 4, by taking into considerations of practical implementation and systems performance, that is,…”

Section: A Modified Ziegler-nichols Methodsmentioning

confidence: 97%

“…(8) are essentially depends upon class of systems.In [5] the relations for different classes of plants was discussed.…”

Section: A Modified Ziegler-nichols Methodsmentioning

confidence: 99%

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Co-ordinate tuning of PID parameters for dynamical systems

Malladi¹,

Yadaiah

2013

2013 IEEE International Conference on Control Applications (CCA)

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This paper proposes a co-ordinate tuning strategy for PID control parameters in achieving both the robustness and better transient characteristics. Modified Ziegler-Nichols, BodeIntegrals and Iso-damping are well known methods for tuning of PID parameters in meeting the desirable. In order to achieve the robustness to gain variations and better transient properties, a new control strategy known as co-ordinate control structure is derived by incorporating the important features of Iso-damping and Bode integral methods. In this process a weightage factor μ is obtained optimally by minimizing Integral Time Absolute Error through Genetic Algorithm (GA). The effectiveness of the proposed scheme has been illustrated with typical systems. I. INTRODUCTIONPID Controllers are extensively being used in Industrial applications because of their simplicity and effectiveness. Due to rapid developments in control technology, there have been different tuning methods reported in the literature [1][2][3]. Among these the Modified Ziegler-Nichols (MZN) [1] method has an advantage of simplicity and works well in many situations of process control applications. In this method, for the given specifications of desired Phase Margin and Gain Crossover frequency, the controller parameters can be selected such that the Nyquist plot passes through the desired location on the unit circle. For designing a PID Controller, however, an additional equation should be introduced which specifies the ratio between integral time and derivative time is α. In order to obtain a unique solution in MZN method, α is selected as 4. Recently, the role of α has drawn much attention and new relationships between T i and T d are presented in [4][5][6] instead of T i = 4T d . In [4][5] it has been shown that the slope of the Nyquist curve at crossover frequency can be adjusted. The design of controller is based on Bode's integrals and only requires the knowledge of the frequency of the system at the crossover frequency as well as its static gain without any model. In [6],a robust PID tuning method was proposed to achieve the flat phase property, that is the phase derivative with respect to the frequency is zero at a given frequency called the tangent frequency, so that the closed-loop system is robust to gain variations and the step responses exhibits Iso-damping property. Flat Phase controller is robust to plant gain variations compared to that of other methods mentioned. Some important suggestions have been made for the improvement of Flat phase controller scheme in [7]. Both the Flat phase controller and controller based on Bode's integrals are preferable compared to MZN

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“…For criterion function in the optimization procedure for PID controller under constraints in frequency domain [18], the proportional gain of controller (max k) which gives the best compromise in performance/robustness is used [40]. In literature, the integral gain for criterion function (max ki) is usually used [31][32][33][34][35][36][37][38][39]. In general case, optimization procedures in the time domain are more demanding because of process with controller transfer function complexity in ACS and corresponding mapping to the time domain.…”

Section: Modern Controller Design Methodsmentioning

confidence: 99%

Modern methods of design, analysis, optimization and implementation of conventional control algorithms for processes with finite and infinite degrees of freedom

Šekara

2017

IJEEC

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-This paper presents characterization methods for a large class of industrial processes using a critical experiment as well as modern methods of design, analysis, optimization and implementation of conventional control algorithms. Special attention is set to the process characterization methods using relay techniques and phase-locked loops in order to form a general process model which serves as a base for adequate controller design. This general process model adequately approximates processes which behaviour can be described with linear mathematical models with finite and infinite degrees of freedom including conventional finite dimension systems, time-delay systems, systems whose behaviour is dominated by a wave and transport problems such as mass and energy transfer, systems described with fractional differential equations etc. Based on characterization, an important accent is also put on the design of PI/PID controller due to their large application in industry which exceeds 93% compared to all the other controllers according to Honeywell's surveys. In order to illustrate validity of characterization model and effectiveness of presented design method, the paper provides an example of optimal PID controller designed under constraints on robustness and sensitivity to the measurement noise. Digital implementation is considered for both the controllers with rational and those with non-rational transfer functions. At the end, controller analytical design methods are elaborated and analytical formulae for PI/PID controllers tuning are presented.

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Loop‐Shaping Design Of Pid Controllers With Constant T_i/T_d RATIO

Cited by 32 publications

References 6 publications

PID design by convex-concave optimization

PID design by convex-concave optimization

Co-ordinate tuning of PID parameters for dynamical systems

Modern methods of design, analysis, optimization and implementation of conventional control algorithms for processes with finite and infinite degrees of freedom

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