Simplified tuning of IMC based modified smith predictor for UFOPDT processes

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Somak Karan ◽  
Chanchal Dey
Keyword(s):  
Closed Loop ◽  
Performance Enhancement ◽  
Chemical Reactor ◽  
Internal Model Control ◽  
Smith Predictor ◽  
Tuning Parameter ◽  
Set Point ◽  
Point Tracking ◽  
Model Control ◽  
Modified Smith Predictor

AbstractA simplified tuning guideline for internal model control (IMC) based modified Smith predictor technique is reported here for unstable lag dominated first-order processes with dead time (UFOPDT). Pole location in right half section of s-plane signifies the unstable behaviour of UFOPDT processes. Mostly, chemical processes like isothermal chemical reactor, bioreactor, dimerization reactor, fluid catalytic cracker etc. are found to be lag dominated and unstable along with considerable time delay. Smith predictor technique based control methodology is considered to be a well-accepted approach for such cases. However, conventional Smith predictor technique is not capable enough for controlling UFOPDT processes. Whereas modified Smith predictor is found to be quite competent in such cases as its design involves more than one controller. Modified Smith predictor structure is capable to provide desirable closed loop response during set point tracking along with the load recovery phases. To mitigate the tuning complexity of multiple controllers involved in modified Smith predictor designing, suggested IMC structure employs single tuning parameter λ i.e. closed loop time constant for all three controllers concerned. Noticeable performance enhancement is reported by the proposed scheme as no overshoot is observed during set point tracking. Moreover, smooth and efficient load rejection behaviour is also obtained. Supremacy of the proposed tuning is established through closed loop performance comparison with others’ reported modified Smith predictor based tuning relations for chemical reactor and bioreactor in terms of performance indices as well as stability margins.

Extended state observer based fractional order controller design for integer high order systems

2021 ◽  
pp. 095440622110621
Author(s):  
Rachid Mansouri ◽  
Maamar Bettayeb ◽  
Ubaid M Al-Saggaf ◽  
Abdulrahman U Alsaggaf ◽  
Muhammad Moinuddin
Keyword(s):  
Fractional Order ◽  
Disturbance Rejection ◽  
State Observer ◽  
Internal Model Control ◽  
Extended State Observer ◽  
Extended State ◽  
Set Point ◽  
Point Tracking ◽  
Model Control ◽  
Fractional Order Controller

In this paper, based on the extended state observer (ESO) and on a fractional order controller (FOC), composed of an integer order PID cascaded with a fractional order filter (FOF), a new control scheme for an n th order integer plant is proposed. The ESO is used to estimate and cancel the unknown internal dynamics and the external disturbance. Afterwards, an FOC is designed to resolve the set-point tracking problem. An analytical and systematic method is proposed to design the FOC. This method is based on the Internal Model Control (IMC) and the Bode’s Ideal Transfer Function (BITF). Therefore, the proposed control structure improves the robustness and performance of the traditional linear active disturbance rejection control (LADRC), especially for the open-loop gain variation. In addition, since the system be controlled is an n th order, a general form of the BITF is also proposed. Numerical simulations on a nonlinear model and experimental results on a cart-pendulum system design illustrate the effectiveness of the suggested ESO-PID-FOF scheme for the disturbance rejection, the set-point tracking and robustness. A comparison with the results obtained using the standard LADRC is also presented.

scholarly journals Robust Output Feedback of Minimum Phase Nonlinear Systems

2007 ◽  
Vol 30 (2) ◽  
pp. 83-91
Author(s):  
Emrod Elisante
Keyword(s):  
Nonlinear Systems ◽  
Output Feedback ◽  
Closed Loop ◽  
Control Structure ◽  
Chemical Reactor ◽  
Internal Model Control ◽  
Minimum Phase ◽  
Robust Tracking ◽  
Model Control ◽  
Multivariable Nonlinear Systems

A robust output feedback controller is synthesized for minimum phase multivariable nonlinear systems based on thedifferential geometry approach. Using the internal model control structure within the input-output (I/O) linearizationframework, the controller is combined with a closed-loop observer to estimate transformed states in the outer-loop. It isshown that the controller-observer combination achieves robust tracking and estimation using simple tuningparameters. The effectiveness of the proposed system is illustrated by a simulation example for control of concentrationin a chemical reactor.

scholarly journals PERANCANGAN METODE INTERNAL MODEL CONTROL 2 DEGREE OF FREEDOM (IMC 2 DOF) UNTUK PENGENDALIAN MODEL SHELL HEAVY OIL FRACTIONATOR (SHOF)

TRANSIENT ◽  
2018 ◽  
Vol 7 (1) ◽  
pp. 40
Author(s):  
Fatamorgana Surgani ◽  
Budi Setiyono ◽  
Sumardi Sumardi
Keyword(s):  
Heavy Oil ◽  
Internal Model ◽  
Dead Time ◽  
Internal Model Control ◽  
Tuning Parameter ◽  
Relative Gain ◽  
Set Point ◽  
First Order ◽  
Model Control ◽  
Relative Gain Array

Shell Heavy Oil Fractionator (SHOF) adalah jenis kolom distilasi yang digunakan untuk memisahkan heavy oil mentah menjadi produk-produk yang diinginkan berdasarkan perbedaan titik didih dari masing-masing produk tersebut. Perancangan kendali pada SHOF memiliki beberapa kendala yang disebabkan oleh non-linearitas pada proses, interaksi multivariabel, adanya waktu tunda (dead time) yang panjang, dan adanya gangguan. Berdasarkan hal tersebut, dibutuhkan metode kendali yang mampu membuat respon sistem mengikuti perubahan set point dan meredam gangguan, sehingga keluaran komposisi produk sesuai dengan yang diharapkan. Pada penelitian ini dibahas perancangan metode IMC 2 DoF untuk pengendalian SHOF MIMO 3x3 terdesentralisasi dalam bentuk fungsi alih first order plus dead time (FOPDT), hal ini dikarenakan metode IMC 2 DoF merupakan salah satu jenis metode kendali modern yang mampu mengendalikan plant multivariabel dan meredam gangguan yang ada. Tuning parameter filter pada pengendali ini menggunakan empat metode tuning parameter filter IMC. Interaksi antar subsistem dikurangi dengan menerapkan metode Relative Gain Array dan melakukan decoupling. Berdasarkan seluruh pengujian yang telah dilakukan, pengendali IMC 2 DoF menggunakan decoupling metode tuning parameter filter Rivera memiliki jumlah nilai IAE terbaik dibandingkan dengan ketiga metode tuning lainnya dengan nilai IAE 93,9585 pada respon , 40,0476 pada respon , dan  0,0102 pada respon .

scholarly journals Disturbance rejection using IMC tuned PID controller with improved filter

2020 ◽  
Vol 20 (3) ◽  
pp. 1261
Author(s):  
B. Mabu Sarif ◽  
D. V. Ashok Kumar ◽  
M. Venu Gopala Rao
Keyword(s):  
Disturbance Rejection ◽  
Pid Controller ◽  
Industrial Applications ◽  
Internal Model Control ◽  
Exceptional Set ◽  
Suggested Approach ◽  
Set Point ◽  
Point Tracking ◽  
Model Control ◽  
Maximal Sensitivity

<p>IMC-PID controllers supply exceptional set point tracking but slow<br />disturbance refutation, because of introduction of slow process pole<br />introduced by the conventional filter. Disturbance rejection is important in<br />many industrial applications over set point tracking. An enhanced IMC filter<br />cascaded with PID controller with Internal Model Control Tuning System<br />(IMC-PID) is presented right now for efficient disruption rejection and<br />reliable first order process operation with time delay (FOPTD). The optional<br />filter does away with the sluggish dominant pole. The present learning shows<br />that the recommended IMC filter provide excellent trouble rejection<br />irrespective of where the trouble enters the procedure and provide high-<br />quality robustness to duplicate deviation in surroundings of accepting in<br />difference with other method cited in the text. Reenactment study was led to<br />show the feasibility of the suggested approach on processes with different 0/r ratios by measuring the controller parameters while retaining the same<br />robustness as regards maximal sensitivity. His efficiency of the closed loops<br />was assessed utilizing integral error parameters. Viz. ISE, ITAE, IAE. The<br />recommended filter provides excellent response pro lag dominant processes.</p>

scholarly journals Set Point Weighted Modified Smith Predictor for Higher Order Integrating Processes with Time Delay

2019 ◽  
Vol 8 (4) ◽  
pp. 11237-11239 ◽  
Keyword(s):  
Time Delay ◽  
Direct Synthesis ◽  
Synthesis Method ◽  
Higher Order ◽  
Smith Predictor ◽  
Control Synthesis ◽  
Pid Controllers ◽  
Set Point ◽  
Point Tracking ◽  
Modified Smith Predictor

This Paper Presents About The Synthesis Of Two-Degree-Of-Freedom Control Structure Based On Modified Smith Predictor Control For Higher Order Integrating Processes With Time Delay. This Control Synthesis Is Done Based On Chengqiang Yin Method. It Has Two Pid Controllers- One Is Set Point Tracking Controller Based On Direct Synthesis Method And The Other Is Disturbance Rejection Controller Based On Imc Principle. In This Work, A Set Point Weight Is Added With Pid Controller To Reduce Peak Overshoots And Settling Time In The Modified Smith Predictor. Two Simulation Examples Are Given To Demonstrate The Validity Of This Method.

scholarly journals 2DOF IMC and Smith-Predictor-Based Control for Stabilised Unstable First Order Time Delayed Plants

Mathematics ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1064
Author(s):  
Mikulas Huba ◽  
Pavol Bistak ◽  
Damir Vrancic
Keyword(s):  
Internal Model ◽  
Closed Loop ◽  
Structural Instability ◽  
Internal Model Control ◽  
Smith Predictor ◽  
Unstable Systems ◽  
First Order ◽  
Long Run ◽  
Model Control ◽  
Two Degree Of Freedom

The article brings a brief revision of the two-degree-of-freedom (2-DoF) internal model control (IMC) and the 2-DoF Smith-Predictor-based (SP) control of unstable systems. It shows that the first important reason for distinguishing between these approaches is the limitations of the control action. However, it also reminds that, in addition to the seemingly lucrative dynamics of transients, the proposed approaches can conceal a tricky behavior with a structural instability, which may manifest itself only after a longer period of time. Instead, as one of possible reliable alternatives, two-step IMC and filtered Smith predictor (FSP) design are applied to unstable first-order time-delayed (UFOTD) systems. Firstly, the 2-DoF P controller yielding a double real dominant closed loop pole is applied. Only then the 2-DoF IMC or FSP controllers are designed, providing slightly slower, but more robust transients. These remain stable even in the long run, while also showing increased robustness.

scholarly journals Enhanced PID Controllers Design Based on Modified Smith Predictor Control for Unstable Process with Time Delay

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Chengqiang Yin ◽  
Jie Gao ◽  
Qun Sun
Keyword(s):  
Time Delay ◽  
Disturbance Rejection ◽  
Direct Synthesis ◽  
Synthesis Method ◽  
Engineering Application ◽  
Smith Predictor ◽  
Superior Performance ◽  
Set Point ◽  
Point Tracking ◽  
Modified Smith Predictor

A two-degree-of-freedom control structure is proposed for a class of unstable processes with time delay based on modified Smith predictor control; the superior performance of disturbance rejection and good robust stability are gained for the system. The set-point tracking controller is designed using the direct synthesis method; the IMC-PID controller for disturbance rejection is designed based on the internal mode control design principle. The controller for set-point response and the controller for disturbance rejection can be adjusted and optimized independently. Meanwhile, the two controllers are designed in the form of PID, which is convenient for engineering application. Finally, simulation examples demonstrate the validity of the proposed control scheme.

scholarly journals An improved 2-degree-of-freedom internal model proportional–integral–derivative controller design for stable time-delay processes

2020 ◽  
Vol 53 (5-6) ◽  
pp. 841-849 ◽  
Author(s):  
Sheng Wu ◽  
Ziwei Li ◽  
Ridong Zhang
Keyword(s):  
Time Delay ◽  
Internal Model ◽  
Degrees Of Freedom ◽  
Control Method ◽  
Controller Design ◽  
Internal Model Control ◽  
Degree Of Freedom ◽  
Set Point ◽  
Point Tracking ◽  
Model Control

In this article, an enhanced 2-degree-of-freedom internal model control strategy for typical industrial processes with time-delay is developed. For the proposed controller, it is composed of an inner loop feedback controller which is designed based on the internal model control theory and a weighted set-point tracking controller. Note that the adjustment of set-point tracking performance and disturbance rejection characteristics can be decoupled by employing the developed strategy, which indicates that more degrees of freedom are obtained for the proposed controller design; thus, better ensemble performance and stronger robustness are anticipated by regulating these two controllers separately, which may not be achieved in the conventional internal model control method. Case studies on two kinds of stable processes with time-delay verify the effectiveness of the proposed scheme finally.

scholarly journals Stabilization of the Magnetic Levitation System

2021 ◽  
Vol 11 (21) ◽  
pp. 10369
Author(s):  
Štefan Chamraz ◽  
Mikuláš Huba ◽  
Katarína Žáková
Keyword(s):  
Closed Loop ◽  
Magnetic Levitation ◽  
Internal Model Control ◽  
Pass Filter ◽  
Low Pass Filter ◽  
First Order ◽  
Model Based ◽  
Model Control ◽  
Levitation System ◽  
Magnetic Levitation System

This paper contributes toward research on the control of the magnetic levitation plant, representing a typical nonlinear unstable system that can be controlled by various methods. This paper shows two various approaches to the solution of the controller design based on different closed loop requirements. Starting from a known unstable linear plant model—the first method is based on the two-step procedure. In the first step, the transfer function of the controlled system is modified to get a stable non-oscillatory system. In the next step, the required first-order dynamic is defined and a model-based PI controller is proposed. The closed loop time constant of this first-order model-based approach can then be used as a tuning parameter. The second set of methods is based on a simplified ultra-local linear approximation of the plant dynamics by the double-integrator plus dead-time (DIPDT) model. Similar to the first method, one possible solution is to stabilize the system by a PD controller combined with a low-pass filter. To eliminate the offset, the stabilized system is supplemented by a simple static feedforward, or by a controller proposed by means of an internal model control (IMC). Another possible approach is to apply for the DIPDT model directly a stabilizing PID controller. The considered solutions are compared to the magnetic levitation system, controlled via the MATLAB/Simulink environment. It is shown that, all three controllers, with integral action, yield much slower dynamics than the stabilizing PD control, which gives one motivation to look for alternative ways of steady-state error compensation, guaranteeing faster setpoint step responses.

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