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

Mathematical Problems in Engineering ◽

10.1155/2014/521460 ◽

2014 ◽

Vol 2014 ◽

pp. 1-7 ◽

Cited By ~ 2

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.

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

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.d9416.118419 ◽

2019 ◽

Vol 8 (4) ◽

pp. 11237-11239 ◽

Cited By ~ 1

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.

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PID Controller Design for TITO Processes Based on IMC and Smith Predictor Configuration

International Journal of Innovative Technology and Exploring Engineering - Special Issue ◽

10.35940/ijitee.f1308.0486s419 ◽

2019 ◽

Vol 8 (6S4) ◽

pp. 1522-1526

Keyword(s):

Time Delay ◽

Disturbance Rejection ◽

Pid Controller ◽

Controller Design ◽

Control Design ◽

Smith Predictor ◽

Point Tracking ◽

Pid Controller Design ◽

Reduced Time

This paper describes the design of ProportionalIntegral-Derivative (PID) controller for two variable processes where the two variables need to control. Design of controllers for such a process is too difficult than single variable processes because of interrelations between the two variables present in the system. Hence, the design approach should include the interrelations of the variables to achieve better performance of the processes. In addition to this, the time delay of the processes is also considered and Smith Predictor (SP) configuration is used to reduce the delay in the processes. For the resultant reduced time delay processes, an IMC approach is used to design PID controller. The proposed control system improves both the servo (set point tracking) and regulatory (disturbance rejection) performance of the system. The proposed configuration is also validated using a case study. The simulation results are presented and compared with the other similar approaches to show the efficacy of the proposed method

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Set point weighted modified Smith predictor for integrating and double integrating processes with time delay

ISA Transactions ◽

10.1016/j.isatra.2006.05.002 ◽

2007 ◽

Vol 46 (1) ◽

pp. 59-71 ◽

Cited By ~ 28

Author(s):

A. Seshagiri Rao ◽

V.S.R. Rao ◽

M. Chidambaram

Keyword(s):

Time Delay ◽

Smith Predictor ◽

Set Point ◽

Modified Smith Predictor

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Modified two-degree-of-freedom Smith predictive control for processes with time-delay

Measurement and Control ◽

10.1177/0020294019898743 ◽

2020 ◽

Vol 53 (3-4) ◽

pp. 691-697 ◽

Cited By ~ 1

Author(s):

Ziwei Li ◽

Jianjun Bai ◽

Hongbo Zou

Keyword(s):

Time Delay ◽

Predictive Control ◽

Control Strategy ◽

Disturbance Rejection ◽

Control Method ◽

Internal Model Control ◽

Degree Of Freedom ◽

Set Point ◽

Point Tracking ◽

Two Degree Of Freedom

This article proposes an improved two-degree-of-freedom Smith predictive control method for typical industrial control systems. Smith predictive control is a classic control strategy designed for systems with pure lag. As an extension of Smith predictive control, internal model control can solve the time-delay problem effectively and make the controller design simple. Based on the two control algorithms, an enhanced control method with modified control structure is developed in this paper. In the design scheme, the set-point tracking and the disturbance rejection characteristics are decoupled, such that the set-point tracking and disturbance rejection controllers can be designed independently to achieve better control performance. The obtained control strategy possesses simple and convenient parameter tuning procedures. The validity of the proposed scheme is verified through theoretical analysis and simulation comparison with other control methods, and the results indicate that the proposed strategy shows better performance on set-point tracking and disturbance rejection.

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Analytical Design for Parallel Cascade Control of Multiple Degrees of Freedom

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.44-47.1417 ◽

2010 ◽

Vol 44-47 ◽

pp. 1417-1421

Author(s):

Cheng Qiang Yin ◽

Jie Gao ◽

Hong Tao Wang

Keyword(s):

Disturbance Rejection ◽

Degrees Of Freedom ◽

Control Program ◽

Smith Predictor ◽

Cascade Control ◽

Primary Loop ◽

Set Point ◽

Multiple Degrees Of Freedom ◽

Point Tracking ◽

Cascade Processes

A new parallel cascade control program of multiple degrees of freedom is proposed for chemical and industrial cascade processes. Firstly, the two degree of freedom IMC structure is adopted in the secondary control loop, and the set-point tracking and disturbance rejection are decoupled, therefore, the influence on performance of primary loop because of the coupling between the set-point tracking and disturbance rejection in the secondary loop is reduced. Then, based on a modified structure of the Smith predictor control, the primary loop realizes the decoupling control between set-point tracking and disturbance rejection, and simple and effective analytical method is adopted to devise the controllers. Finally, simulations example demonstrates the validity of the proposed control scheme.

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PID Controller Design for Tito Processes Based on IMC and Smith Predictor Configuration

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.b1198.0782s319 ◽

2019 ◽

Vol 8 (2S3) ◽

pp. 1060-1063

Keyword(s):

Time Delay ◽

Disturbance Rejection ◽

Pid Controller ◽

Controller Design ◽

Smith Predictor ◽

Proportional Integral Derivative ◽

Point Tracking ◽

Pid Controller Design ◽

Reduced Time

This paper describes the design of Proportional-Integral-Derivative (PID) controller for two variable processes where the two variables need to control. Design of controllers for such a process is too difficult than single variable processes because of interrelations between the two variables present in the system. Hence, the design approach should include the interrelations of the variables to achieve better performance of the processes. In addition to this, the time delay of the processes is also considered and Smith Predictor (SP) configuration is used to reduce the delay in the processes. For the resultant reduced time delay processes, an IMC approach is used to design PID controller. The proposed control system improves both the servo (set point tracking) and regulatory (disturbance rejection) performance of the system. The proposed configuration is also validated using a case study. The simulation results are presented and compared with the other similar approaches to show the efficacy of the proposed method.

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Simplified tuning of IMC based modified smith predictor for UFOPDT processes

Chemical Product and Process Modeling ◽

10.1515/cppm-2019-0132 ◽

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.

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A Modified 2-DOF Control Framework and GA Based Intelligent Tuning of PID Controllers

Processes ◽

10.3390/pr9030423 ◽

2021 ◽

Vol 9 (3) ◽

pp. 423

Author(s):

Gun-Baek So

Keyword(s):

Disturbance Rejection ◽

Pid Controller ◽

Weighting Function ◽

Pid Controllers ◽

Set Point ◽

Tuning Method ◽

Point Tracking ◽

Load Disturbance ◽

Control Framework ◽

Feedforward Controller

Although a controller is well-tuned for set-point tracking, it shows poor control results for load disturbance rejection and vice versa. In this paper, a modified two-degree-of-freedom (2-DOF) control framework to solve this problem is proposed, and an optimal tuning method for the pa-rameters of each proportional integral derivative (PID) controller is discussed. The unique feature of the proposed scheme is that a feedforward controller is embedded in the parallel control structure to improve set-point tracking performance. This feedforward controller and the standard PID con-troller are combined to create a new set-point weighted PID controller with a set-point weighting function. Therefore, in this study, two controllers are used: a set-point weighted PID controller for set-point tracking and a conventional PID controller for load disturbance rejection. The parameters included in the two controllers are tuned separately to improve set-point tracking and load dis-turbance rejection performances, respectively. Each controller is optimally tuned by genetic algo-rithm (GA) in terms of minimizing the IAE performance index, and what is special at this time is that it also tunes the set-point weighting parameter simultaneously. The simulation results performed on four virtual processes verify that the proposed method shows better performance in set-point tracking and load disturbance rejection than those of the other methods.

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