The document summarizes a study on model-based controller design for a first-order plus time delay (FOPTD) system. The study identifies the process model of a level control system using process reaction curve methods. Various tuning rules for internal model control-proportional integral derivative (IMC-PID) controllers from literature are applied to the system, including rules from Rivera, Chien, Lee, Skogestad, and Panda. The performance of each controller is evaluated based on rise time, settling time, percentage overshoot, integral absolute error, and integral of time multiplied absolute error. The study finds that the Panda tuning rule has the smallest percentage overshoot and integral absolute error, while the Chien rule has
Closed-loop step response for tuning PID fractional-order filter controllersISA Interchange
Analytical methods are usually applied for tuning fractional controllers. The present paper proposes an empirical method for tuning a new type of fractional controller known as PID-Fractional-Order-Filter (FOF-PID). Indeed, the setpoint overshoot method, initially introduced by Shamsuzzoha and Skogestad, has been adapted for tuning FOF-PID controller. Based on simulations for a range of first order with time delay processes, correlations have been derived to obtain PID-FOF controller parameters similar to those obtained by the Internal Model Control (IMC) tuning rule. The setpoint overshoot method requires only one closed-loop step response experiment using a proportional controller (P-controller). To highlight the potential of this method, simulation results have been compared with those obtained with the IMC method as well as other pertinent techniques. Various case studies have also been considered. The comparison has revealed that the proposed tuning method performs as good as the IMC. Moreover, it might offer a number of advantages over the IMC tuning rule. For instance, the parameters of the frac- tional controller are directly obtained from the setpoint closed-loop response data without the need of any model of the plant to be controlled.
FRACTIONAL ORDER PID CONTROLLER TUNING BASED ON IMC IJITCA Journal
In this work, a class of fractional order controller (FOPID) is tuned based on internal model control
(IMC). This tuning rule has been obtained without any approximation of time delay. Moreover to show
usefulness of fractional order controller in comparison with classical integer order controllers, an
industrial PID controller tuned in a similar way, is compared with FOPID and then robust stability of both
controllers is investigated. Robust stability analysis has been done to find maximum delayed time
uncertainty interval which results in a stable closed loop control system. For a typical system, robust
stability has been done to find maximum time constant uncertainty interval of system. Two clarify the
proposed control system design procedure, three examples have been given.
Tuning of IMC-based PID controllers for integrating systems with time delayISA Interchange
Design of Proportional Integral and Derivative (PID) controllers based on IMC principles for various types of integrating systems with time delay is proposed. PID parameters are given in terms of process model parameters and a tuning parameter. The tuning parameter is IMC filter time constant. In the present work, the IMC filter (Q) is chosen in such a manner that the order of the denominator of IMC controller is one less than the order of the numerator. The IMC filter time constant (λ) is tuned in such a way that a good compromise is made between performance and robustness for both servo and regulatory problems. To improve servo response of the controller a set point filter is designed such that the closed loop response is similar to that of first order plus time delay system. The proposed controller design method is applied to various transfer function models and to the non-linear model equations of jacketed CSTR to demonstrate its applicability and effectiveness. The performance of the proposed controller is compared with the recently reported methods in terms of IAE and ITAE. The smooth functioning of the controller is determined in terms of total variation and compared with recently reported methods. Simulation studies are carried out on various integrating systems with time delay to show the effectiveness and superiority of the proposed controllers.
Design of a new PID controller using predictive functional control optimizati...ISA Interchange
An improved proportional integral derivative (PID) controller based on predictive functional control (PFC) is proposed and tested on the chamber pressure in an industrial coke furnace. The proposed design is motivated by the fact that PID controllers for industrial processes with time delay may not achieve the desired control performance because of the unavoidable model/plant mismatches, while model predictive control (MPC) is suitable for such situations. In this paper, PID control and PFC algorithm are combined to form a new PID controller that has the basic characteristic of PFC algorithm and at the same time, the simple structure of traditional PID controller. The proposed controller was tested in terms of set-point tracking and disturbance rejection, where the obtained results showed that the proposed controller had the better ensemble performance compared with traditional PID controllers.
Comparison Analysis of Model Predictive Controller with Classical PID Control...ijeei-iaes
pH control plays a important role in any chemical plant and process industries. For the past four decades the classical PID controller has been occupied by the industries. Due to the faster computing technology in the industry demands a tighter advanced control strategy. To fulfill the needs and requirements Model Predictive Control (MPC) is the best among all the advanced control algorithms available in the present scenario. The study and analysis has been done for First Order plus Delay Time (FOPDT) model controlled by Proportional Integral Derivative (PID) and MPC using the Matlab software. This paper explores the capability of the MPC strategy, analyze and compare the control effects with conventional control strategy in pH control. A comparison results between the PID and MPC is plotted using the software. The results clearly show that MPC provide better performance than the classical controller.
Controller Tuning for Integrator Plus Delay Processes.theijes
A design method for PID controllers based on internal model control (IMC) principles, direct synthesis method (DS), stability analysis (SA) method for pure integrating process with time delay is proposed. Analytical expressions for PID controllers are derived for several common types of process models, including first order and second-order plus time delay models and an integrator plus time delay model. Here in this paper, a simple controller design rule and tuning procedure for unstable processes with delay time is discussed. Simulation examples are included to show the effectiveness of the proposed method
Closed-loop step response for tuning PID fractional-order filter controllersISA Interchange
Analytical methods are usually applied for tuning fractional controllers. The present paper proposes an empirical method for tuning a new type of fractional controller known as PID-Fractional-Order-Filter (FOF-PID). Indeed, the setpoint overshoot method, initially introduced by Shamsuzzoha and Skogestad, has been adapted for tuning FOF-PID controller. Based on simulations for a range of first order with time delay processes, correlations have been derived to obtain PID-FOF controller parameters similar to those obtained by the Internal Model Control (IMC) tuning rule. The setpoint overshoot method requires only one closed-loop step response experiment using a proportional controller (P-controller). To highlight the potential of this method, simulation results have been compared with those obtained with the IMC method as well as other pertinent techniques. Various case studies have also been considered. The comparison has revealed that the proposed tuning method performs as good as the IMC. Moreover, it might offer a number of advantages over the IMC tuning rule. For instance, the parameters of the frac- tional controller are directly obtained from the setpoint closed-loop response data without the need of any model of the plant to be controlled.
FRACTIONAL ORDER PID CONTROLLER TUNING BASED ON IMC IJITCA Journal
In this work, a class of fractional order controller (FOPID) is tuned based on internal model control
(IMC). This tuning rule has been obtained without any approximation of time delay. Moreover to show
usefulness of fractional order controller in comparison with classical integer order controllers, an
industrial PID controller tuned in a similar way, is compared with FOPID and then robust stability of both
controllers is investigated. Robust stability analysis has been done to find maximum delayed time
uncertainty interval which results in a stable closed loop control system. For a typical system, robust
stability has been done to find maximum time constant uncertainty interval of system. Two clarify the
proposed control system design procedure, three examples have been given.
Tuning of IMC-based PID controllers for integrating systems with time delayISA Interchange
Design of Proportional Integral and Derivative (PID) controllers based on IMC principles for various types of integrating systems with time delay is proposed. PID parameters are given in terms of process model parameters and a tuning parameter. The tuning parameter is IMC filter time constant. In the present work, the IMC filter (Q) is chosen in such a manner that the order of the denominator of IMC controller is one less than the order of the numerator. The IMC filter time constant (λ) is tuned in such a way that a good compromise is made between performance and robustness for both servo and regulatory problems. To improve servo response of the controller a set point filter is designed such that the closed loop response is similar to that of first order plus time delay system. The proposed controller design method is applied to various transfer function models and to the non-linear model equations of jacketed CSTR to demonstrate its applicability and effectiveness. The performance of the proposed controller is compared with the recently reported methods in terms of IAE and ITAE. The smooth functioning of the controller is determined in terms of total variation and compared with recently reported methods. Simulation studies are carried out on various integrating systems with time delay to show the effectiveness and superiority of the proposed controllers.
Design of a new PID controller using predictive functional control optimizati...ISA Interchange
An improved proportional integral derivative (PID) controller based on predictive functional control (PFC) is proposed and tested on the chamber pressure in an industrial coke furnace. The proposed design is motivated by the fact that PID controllers for industrial processes with time delay may not achieve the desired control performance because of the unavoidable model/plant mismatches, while model predictive control (MPC) is suitable for such situations. In this paper, PID control and PFC algorithm are combined to form a new PID controller that has the basic characteristic of PFC algorithm and at the same time, the simple structure of traditional PID controller. The proposed controller was tested in terms of set-point tracking and disturbance rejection, where the obtained results showed that the proposed controller had the better ensemble performance compared with traditional PID controllers.
Comparison Analysis of Model Predictive Controller with Classical PID Control...ijeei-iaes
pH control plays a important role in any chemical plant and process industries. For the past four decades the classical PID controller has been occupied by the industries. Due to the faster computing technology in the industry demands a tighter advanced control strategy. To fulfill the needs and requirements Model Predictive Control (MPC) is the best among all the advanced control algorithms available in the present scenario. The study and analysis has been done for First Order plus Delay Time (FOPDT) model controlled by Proportional Integral Derivative (PID) and MPC using the Matlab software. This paper explores the capability of the MPC strategy, analyze and compare the control effects with conventional control strategy in pH control. A comparison results between the PID and MPC is plotted using the software. The results clearly show that MPC provide better performance than the classical controller.
Controller Tuning for Integrator Plus Delay Processes.theijes
A design method for PID controllers based on internal model control (IMC) principles, direct synthesis method (DS), stability analysis (SA) method for pure integrating process with time delay is proposed. Analytical expressions for PID controllers are derived for several common types of process models, including first order and second-order plus time delay models and an integrator plus time delay model. Here in this paper, a simple controller design rule and tuning procedure for unstable processes with delay time is discussed. Simulation examples are included to show the effectiveness of the proposed method
DESIGN OF PID CONTROLLERS INTEGRATOR SYSTEM WITH TIME DELAY AND DOUBLE INTEGR...ijics
In this paper first we investigate optimal PID control of a double integrating plus delay process and compare with the SIMC rules. What makes the double integrating process special is that derivative action is actually necessary for stabilization. In control, there is generally a trade-off between performance and
robustness, so there does not exist a single optimal controller. However, for a given robustness level (here defined in terms of the Ms-value) we can find the optimal controller which minimizes the performance J (here defined as the integrated absolute error (IAE)-value for disturbances). Interestingly, the SIMC PID controller is almost identical to the optimal pid controller. This can be seen by comparing the paretooptimal
curve for J as a function of Ms, with the curve found by varying the SIMC tuning parameter Tc.
Second, design of Proportional Integral and Derivative (PID) controllers based on internal model control (IMC) principles, direct synthesis method (DS), stability analysis (SA) method for pure integrating process with time delay is proposed. The performances of the proposed controllers are compared with the
controllers designed by recently reported methods. The robustness of the proposed controllers for the uncertainty in model parameters is evaluated considering one parameter at a time using Kharitonov’s theorem. The proposed controllers are applied to various transfer function models and to non linear model of isothermal continuous copolymerization of styrene-acrylonitrile in CSTR. An experimental set up of tank
with the outlet connected to a pump is considered for implementation of the PID controllers designed by
the three proposed methods to show the effectiveness of the methods.
Disturbance Rejection with a Highly Oscillating Second-Order Process, Part I...Scientific Review SR
This research paper aims at investigating disturbance rejection associated with a highly oscillating
second-order process. The PD-PI controller having three parameters are tuned to provide efficient rejection of a
step input disturbance input. Controller tuning based on using MATLAB control and optimization toolboxes.
Using the suggested tuning technique, it is possible to reduce the maximum time response of the closed loop
control system to as low as 0.0095 and obtain time response to the disturbance input having zero settling time.
The effect of the proportional gain of the PD-PI controller on the control system dynamics is investigated for a
gain ≤ 100. The performance of the control system during disturbance rejection using the PD -PI controller is
compared with that using a second-order compensator. The PD-PI controller is superior in dealing with the
disturbance rejection associated with the highly oscillating second-order process
Tuning of PID controllers for integrating systems using direct synthesis methodISA Interchange
A PID controller is designed for various forms of integrating systems with time delay using direct synthesis method. The method is based on comparing the characteristic equation of the integrating system and PID controller with a filter with the desired characteristic equation. The desired characteristic equation comprises of multiple poles which are placed at the same desired location. The tuning parameter is adjusted so as to achieve the desired robustness. Tuning rules in terms of process parameters are given for various forms of integrating systems. The tuning parameter can be selected for the desired robustness by specifying Ms value. The proposed controller design method is applied to various transfer function models and to the nonlinear model equations of jacketed CSTR to show its effectiveness and applicability.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
On the fragility of fractional-order PID controllers for FOPDT processesISA Interchange
This paper analyzes the fragility issue of fractional-order proportional-integral-derivative controllers applied to integer first-order plus-dead-time processes. In particular, the effects of the variations of the controller parameters on the achieved control system robustness and performance are investigated. Results show that this kind of controllers is more fragile with respect to the standard proportional-integral-derivative controllers and therefore a significant attention should be paid by the user in their tuning.
Distributed Control System Applied in Temperatur Control by Coordinating Mult...TELKOMNIKA JOURNAL
In Distributed Control System (DCS), multitasking management has been important issues
continuously researched and developed. In this paper, DCS was applied in global temperature control
system by coordinating three Local Control Units (LCUs). To design LCU’s controller parameters, both
analytical and experimental method were employed. In analytical method, the plants were firstly identified
to get their transfer functions which were then used to derive control parameters based on desired
response qualities. The experimental method (Ziegler-Nichols) was also applied due to practicable reason
in real industrial plant (less mathematical analysis). To manage set-points distributed to all LCUs, master
controller was subsequently designed based on zone of both error and set-point of global temperature
controller. Confirmation experiments showed that when using control parameters from analytical method,
the global temperature response could successfully follow the distributed set-points with 0% overshoot,
193.92 second rise time, and 266.88 second settling time. While using control parameters from
experimental method, it could also follow the distributed set-points with presence of overshoot (16.9%), but
has less rise time and settling time (111.36 and 138.72 second). In this research, the overshoot could be
successfully decreased from 16.9 to 9.39 % by changing master control rule. This proposed method can
be potentially applied in real industrial plant due to its simplicity in master control algorithm and presence
of PID controller which has been generally included in today industrial equipments.
Comparison of Tuning Methods of PID Controllers for Non-Linear Systempaperpublications3
Abstract: Modern days have seen vast developments in the field of controller’s .There are various controllers developed these days with various different specifications. But the only drawback is that, there is no fixed method for the tuning of these controllers, which is necessary for controlling of the system based on the variation of the input or for the changes in the system. In order to overcome this drawback, in this paper we have compared various tuning methods of PID controller for non-linear system. As a non-linear system we have taken the dc motor as a system. For the particular DC motor controller transfer function has been determined and control parameters such as Proportional Gain, Integral Time and Derivative time are identified. They are numerous methods of developing a Proportional Integral and Derivative (PID) Controller, amongst them some methods are adopted in this paper and Comparisons of Time Domain specifications of those controllers has been carried out.
MODEL BASED ANALYSIS OF TEMPERATURE PROCESS UNDER VARIOUS CONTROL STRATEGIES ...Journal For Research
This paper analyze the temperature process in an empirical model. From the empirical model the system behavior is determined by transfer function and the basic controller strategies Ziegler-Nichols & Cohen-Coon method are implemented in it. With these tuning methods the best control strategies are obtained at the final stage by interfacing the system with NI-myRIO kit.
Optimised control using Proportional-Integral-Derivative controller tuned usi...IJECEIAES
Time delays are generally unavoidable in the designing frameworks for mechanical and electrical systems and so on. In both continuous and discrete schemes, the existence of delay creates undesirable impacts on the underthought which forces exacting constraints on attainable execution. The presence of delay confounds the design structure procedure also. It makes continuous systems boundless dimensional and also extends the readings in discrete systems fundamentally. As the Proportional-IntegralDerivative (PID) controller based on internal model control is essential and strong to address the vulnerabilities and aggravations of the model. But for an real industry process, they are less susceptible to noise than the PID controller.It results in just one tuning parameter which is the time constant of the closed-loop system λ, the internal model control filter factor. It additionally gives a decent answer for the procedure with huge time delays. The design of the PID controller based on the internal model control, with approximation of time delay using Pade’ and Taylor’s series is depicted in this paper. The first order filter used in the design provides good set-point tracking along with disturbance rejection.
Enhanced self-regulation nonlinear PID for industrial pneumatic actuatorIJECEIAES
The present article describes the improvement of Self-regulation Nonlinear PID (SN-PID) controller. A new function is introduced to improve the system performance in terms of transient without affecting the steady state performance. It is used to optimize the nonlinear function available on this controller. The signal error is reprocessed through this function, and the result is used to tune the nonlinear function of the controller. Furthermore, the presence of the dead zone on the proportional valve is solved using Dead Zone Compensator (DZC). Simulations and experiments were carried out on the pneumatic positioning system. Comparisons between the existing methods were examined and successfully demonstrated.
The problem of controlling an unstable delayed double integrating process with fractional delay using a
feed forward first-order lag-lead compensator is studied. The effect of time delay of the process in a range between
0.1 and 0.9 seconds is considered. The compensator is tuned using MATLAB optimization toolbox with five forms
of the objective function in terms of the error between the step time response of the closed-loop control system and
the response steady-state value. Using the proposed compensator with the fractional delayed double integrating
process indicates the robustness of the compensator in the time delay range used with superior time-based
specifications compared with other technique based on PID controller.
Keywords — Delayed double integrating process with fractional delay, Feed forward lag-lead first-order
compensator, compensator tuning, MATLAB optimization toolbox, Control system performance.
DESIGN OF PID CONTROLLERS INTEGRATOR SYSTEM WITH TIME DELAY AND DOUBLE INTEGR...ijics
In this paper first we investigate optimal PID control of a double integrating plus delay process and compare with the SIMC rules. What makes the double integrating process special is that derivative action is actually necessary for stabilization. In control, there is generally a trade-off between performance and
robustness, so there does not exist a single optimal controller. However, for a given robustness level (here defined in terms of the Ms-value) we can find the optimal controller which minimizes the performance J (here defined as the integrated absolute error (IAE)-value for disturbances). Interestingly, the SIMC PID controller is almost identical to the optimal pid controller. This can be seen by comparing the paretooptimal
curve for J as a function of Ms, with the curve found by varying the SIMC tuning parameter Tc.
Second, design of Proportional Integral and Derivative (PID) controllers based on internal model control (IMC) principles, direct synthesis method (DS), stability analysis (SA) method for pure integrating process with time delay is proposed. The performances of the proposed controllers are compared with the
controllers designed by recently reported methods. The robustness of the proposed controllers for the uncertainty in model parameters is evaluated considering one parameter at a time using Kharitonov’s theorem. The proposed controllers are applied to various transfer function models and to non linear model of isothermal continuous copolymerization of styrene-acrylonitrile in CSTR. An experimental set up of tank
with the outlet connected to a pump is considered for implementation of the PID controllers designed by
the three proposed methods to show the effectiveness of the methods.
Disturbance Rejection with a Highly Oscillating Second-Order Process, Part I...Scientific Review SR
This research paper aims at investigating disturbance rejection associated with a highly oscillating
second-order process. The PD-PI controller having three parameters are tuned to provide efficient rejection of a
step input disturbance input. Controller tuning based on using MATLAB control and optimization toolboxes.
Using the suggested tuning technique, it is possible to reduce the maximum time response of the closed loop
control system to as low as 0.0095 and obtain time response to the disturbance input having zero settling time.
The effect of the proportional gain of the PD-PI controller on the control system dynamics is investigated for a
gain ≤ 100. The performance of the control system during disturbance rejection using the PD -PI controller is
compared with that using a second-order compensator. The PD-PI controller is superior in dealing with the
disturbance rejection associated with the highly oscillating second-order process
Tuning of PID controllers for integrating systems using direct synthesis methodISA Interchange
A PID controller is designed for various forms of integrating systems with time delay using direct synthesis method. The method is based on comparing the characteristic equation of the integrating system and PID controller with a filter with the desired characteristic equation. The desired characteristic equation comprises of multiple poles which are placed at the same desired location. The tuning parameter is adjusted so as to achieve the desired robustness. Tuning rules in terms of process parameters are given for various forms of integrating systems. The tuning parameter can be selected for the desired robustness by specifying Ms value. The proposed controller design method is applied to various transfer function models and to the nonlinear model equations of jacketed CSTR to show its effectiveness and applicability.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
On the fragility of fractional-order PID controllers for FOPDT processesISA Interchange
This paper analyzes the fragility issue of fractional-order proportional-integral-derivative controllers applied to integer first-order plus-dead-time processes. In particular, the effects of the variations of the controller parameters on the achieved control system robustness and performance are investigated. Results show that this kind of controllers is more fragile with respect to the standard proportional-integral-derivative controllers and therefore a significant attention should be paid by the user in their tuning.
Distributed Control System Applied in Temperatur Control by Coordinating Mult...TELKOMNIKA JOURNAL
In Distributed Control System (DCS), multitasking management has been important issues
continuously researched and developed. In this paper, DCS was applied in global temperature control
system by coordinating three Local Control Units (LCUs). To design LCU’s controller parameters, both
analytical and experimental method were employed. In analytical method, the plants were firstly identified
to get their transfer functions which were then used to derive control parameters based on desired
response qualities. The experimental method (Ziegler-Nichols) was also applied due to practicable reason
in real industrial plant (less mathematical analysis). To manage set-points distributed to all LCUs, master
controller was subsequently designed based on zone of both error and set-point of global temperature
controller. Confirmation experiments showed that when using control parameters from analytical method,
the global temperature response could successfully follow the distributed set-points with 0% overshoot,
193.92 second rise time, and 266.88 second settling time. While using control parameters from
experimental method, it could also follow the distributed set-points with presence of overshoot (16.9%), but
has less rise time and settling time (111.36 and 138.72 second). In this research, the overshoot could be
successfully decreased from 16.9 to 9.39 % by changing master control rule. This proposed method can
be potentially applied in real industrial plant due to its simplicity in master control algorithm and presence
of PID controller which has been generally included in today industrial equipments.
Comparison of Tuning Methods of PID Controllers for Non-Linear Systempaperpublications3
Abstract: Modern days have seen vast developments in the field of controller’s .There are various controllers developed these days with various different specifications. But the only drawback is that, there is no fixed method for the tuning of these controllers, which is necessary for controlling of the system based on the variation of the input or for the changes in the system. In order to overcome this drawback, in this paper we have compared various tuning methods of PID controller for non-linear system. As a non-linear system we have taken the dc motor as a system. For the particular DC motor controller transfer function has been determined and control parameters such as Proportional Gain, Integral Time and Derivative time are identified. They are numerous methods of developing a Proportional Integral and Derivative (PID) Controller, amongst them some methods are adopted in this paper and Comparisons of Time Domain specifications of those controllers has been carried out.
MODEL BASED ANALYSIS OF TEMPERATURE PROCESS UNDER VARIOUS CONTROL STRATEGIES ...Journal For Research
This paper analyze the temperature process in an empirical model. From the empirical model the system behavior is determined by transfer function and the basic controller strategies Ziegler-Nichols & Cohen-Coon method are implemented in it. With these tuning methods the best control strategies are obtained at the final stage by interfacing the system with NI-myRIO kit.
Optimised control using Proportional-Integral-Derivative controller tuned usi...IJECEIAES
Time delays are generally unavoidable in the designing frameworks for mechanical and electrical systems and so on. In both continuous and discrete schemes, the existence of delay creates undesirable impacts on the underthought which forces exacting constraints on attainable execution. The presence of delay confounds the design structure procedure also. It makes continuous systems boundless dimensional and also extends the readings in discrete systems fundamentally. As the Proportional-IntegralDerivative (PID) controller based on internal model control is essential and strong to address the vulnerabilities and aggravations of the model. But for an real industry process, they are less susceptible to noise than the PID controller.It results in just one tuning parameter which is the time constant of the closed-loop system λ, the internal model control filter factor. It additionally gives a decent answer for the procedure with huge time delays. The design of the PID controller based on the internal model control, with approximation of time delay using Pade’ and Taylor’s series is depicted in this paper. The first order filter used in the design provides good set-point tracking along with disturbance rejection.
Enhanced self-regulation nonlinear PID for industrial pneumatic actuatorIJECEIAES
The present article describes the improvement of Self-regulation Nonlinear PID (SN-PID) controller. A new function is introduced to improve the system performance in terms of transient without affecting the steady state performance. It is used to optimize the nonlinear function available on this controller. The signal error is reprocessed through this function, and the result is used to tune the nonlinear function of the controller. Furthermore, the presence of the dead zone on the proportional valve is solved using Dead Zone Compensator (DZC). Simulations and experiments were carried out on the pneumatic positioning system. Comparisons between the existing methods were examined and successfully demonstrated.
The problem of controlling an unstable delayed double integrating process with fractional delay using a
feed forward first-order lag-lead compensator is studied. The effect of time delay of the process in a range between
0.1 and 0.9 seconds is considered. The compensator is tuned using MATLAB optimization toolbox with five forms
of the objective function in terms of the error between the step time response of the closed-loop control system and
the response steady-state value. Using the proposed compensator with the fractional delayed double integrating
process indicates the robustness of the compensator in the time delay range used with superior time-based
specifications compared with other technique based on PID controller.
Keywords — Delayed double integrating process with fractional delay, Feed forward lag-lead first-order
compensator, compensator tuning, MATLAB optimization toolbox, Control system performance.
IOSR Journal of Pharmacy and Biological Sciences(IOSR-JPBS) is an open access international journal that provides rapid publication (within a month) of articles in all areas of Pharmacy and Biological Science. The journal welcomes publications of high quality papers on theoretical developments and practical applications in Pharmacy and Biological Science. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
In this paper, the terms chained ternary semigroup, cancellable clement , cancellative ternary
semigroup, A-regular element, π- regular element, π- invertible element, noetherian ternary semigroup are
introduced. It is proved that in a commutative chained ternary semigroup T, i) if P is a prime ideal of T and
x ∉ P then n
n 1
x PT
= P for all odd natural numbers n . ii) T is a semiprimary ternary semigroup. iii) If a ε T is
a semisimple element of T, then < a > w ≠ . iv) If < a >w = 𝜙 for all a ε T, then T has no semisimple
elements. v) T has no regular elements, then for any a ε T, < a >w = 𝜙 or < a >w is a prime ideal. vi) If T is a
commutative chained cancellative ternary semigroup then for every non π-invertible element a, < a >w is either
empty or a prime ideal of T. Further it is proved that if T is a chained ternary semigroup with T\T3= { x } for
some x ε T, then i) T\ { x } is an ideal of T. ii) T = xT1T1 = T1xT1 = T1T1x and T 3 = xTT = TxT = TTx is the
unique maximal ideal of T. iii) If a T and a < x >w then a = xn for some odd natural number n > 1.
iv) T\ < x >w = { x, x 3, x5, . . . . .} or T\< x >w ={x, x 3, . . . , xr} for some odd natural number r. v) If a T
and a < x >w then a = xr for some odd natural number r or a = xn sn tn and sn < x >w or tn < x >w
for every odd natural number n. vi) If T contains cancellable elements then x is cancellable element and < x >w
is either empty or a prime ideal of T. It is also prove that, in a commutative chained ternary semigroup T,
T is archemedian ternary semigroup without idempotent elements if and only if < a >w = for every a T.
Further it is proved that if T is a commutative chained ternary semigroup containing cancellable elements and
< a >w = for every a T , then T is a cancellative ternary semigroup. It is proved that if T is a noetherian
ternary semigroup containing proper ideals then T has a maximal ideal. Finally it is proved that if T is a
commutative ternary semigroup such that T = < x > for some x T, then the following are equivalent.
1) T = {x, x2, x3, ............} is infinite. 2) T is a noetherian cancellative ternary semigroup with x xTT.
3) T is a noetherian cancellative ternary semigroup without idempotents. 4) < a >w = for all a T.
5) < x >w = . and if T is a commutative chained ternary semigroup with T ≠ T 3 , then the following are
equivalent. (1) T={x, x 3, x5, . . . . . . .}, where x T\ T 3 (2) T is Noetherian cancellative ternary semigroup
without idempotents. (3) < a >w = for all a T. Finally, it is proved that If T is a commutative chained
noetherian cancellative ternary semigroup without regular elements, then < a >w = for all a T.
Studies On The Effectiveness of Mixed Diet of Garden Egg, Groundnut And Garli...IOSR Journals
The use of medicinal plants as food supplements and in the treatment of specific diseases dates back to antiquity. Age old anecdotal reports from many cultures strongly suggests a role for diet of plant origin in preventive and therapeutic medicine. Anaemia remains a major public-health problem especially in developing countries. This study aimed at investigating the antianaemic potentials of combined diet of garlic (Allium sativum), garden egg (Solanum melongena) and groundnut (Arachis hypogaea).Twenty five wistar rats of both sexes weighing 160-200g were divided equally into five groups. Group 1 served as the non-anaemic control and fed with normal rat chow. Groups 2, 3, 4 and 5 were induced with anaemia by oral administration of phenylhydrazine (PHZ) given at 50mg/kgBW. Group 2 served as anaemic control, fed with normal rat chow; Group 3 were fed with 20g (75%ww) of garlic, garden egg and groundnut in the ratio of 1:1:1 with normal rat chow; Group 4 fed with 10g of garden egg (50%ww) in the ratio 1:1 with normal rat chow and Group 5 fed with 10g of ground, nut (50%ww) in the ratio 1:1 with normal rat chow. Animals were sacrificed at the end of fourteen days of dietary feeding using chloroform vapour with blood collected at the left ventricle to test for haematological parameters such as red blood cell (RBC) count, white blood cell (WBC) count, hemoglobin concentration (Hb) and packed cell volume (PCV). Results showed that RBC, WBC, Hb and PCV values increased in all the experimental as compared to anaemic control with a significant (P<0.05) in WBC values of groups 3 and 4 as compared to the anaemic control. This suggests a consumption of garlic, garden egg and groundnut will moderately improve anaemic condition.
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considered that it behaves like an antenna for electromagnetic radiation. In this paper the total amount of
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controllers designed by recently reported methods. The robustness of the proposed controllers for the uncertainty in model parameters is evaluated considering one parameter at a time using Kharitonov’s theorem. The proposed controllers are applied to various transfer function models and to non linear model of isothermal continuous copolymerization of styrene-acrylonitrile in CSTR. An experimental set up of tank with the outlet connected to a pump is considered for implementation of the PID controllers designed by the three proposed methods to show the effectiveness of the methods.
Analysis and Modeling of PID and MRAC Controllers for a Quadruple Tank System...dbpublications
Multivariable systems exhibit complex dynamics because of the interactions between input variables and output variables. In this paper an approach to design auto tuned decentralized PI controller using ideal decoupler and adaptive techniques for controlling a class of multivariable process with a transmission zero. By using decoupler, the MIMO system is transformed into two SISO systems. The controller parameters were adjusted using the Model Reference Adaptive reference Control. In recent process industries, PID and MRAC are the two widely accepted control strategies, where PID is used at regulatory level control and MRAC at supervisory level control. In this project, LabVIEW is used to simulate the PID with Decoupler and MRAC separately and analyze their performance based on steady state error tracking and overshoot.
Dynamic Matrix Control (DMC) on jacket tank heater - Rishikesh BagweRishikesh Bagwe
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COMPARATIVE ANALYSIS OF CONVENTIONAL PID CONTROLLER AND FUZZY CONTROLLER WIT...IJITCA Journal
All the real systems exhibits non-linear nature,conventional controllers are not always able to provide good and accurate results. Fuzzy Logic Control is used to obtain better response. A model for simulation is designed and all the assumptions are made before the development of the model. An attempt has been made to analyze the efficiency of a fuzzy controller over a conventional PID controller for a three tank level control system using fuzzification & defuzzification methods and their responses are compared. Analysis is done through computer simulation using Matlab/Simulink toolbox. This study shows that the application of Fuzzy Logic Controller (FLC) gives the best response with triangular membership function and centroid defuzzification method.
Design of a model reference adaptive PID control algorithm for a tank system IJECEIAES
This paper describes the design of an adaptive controller based on model reference adaptive PID control (MRAPIDC) to stabilize a two-tank process when large variations of parameters and external disturbances affect the closed-loop system. To achieve that, an innovative structure of the adaptive PID controller is defined, an additional PI is designed to make sure that the reference model produces stable output signals and three adaptive gains are included to guarantee stability and robustness of the closed-loop system. Then, the performance of the model reference adaptive PID controller on the behaviour of the closed-loop system is compared to a PI controller designed on MATLAB when both closed-loop systems are under various conditions. The results demonstrate that the MRAPIDC performs significantly better than the conventional PI controller.
A novel auto-tuning method for fractional order PID controllersISA Interchange
Fractional order PID controllers benefit from an increasing amount of interest from the research community due to their proven advantages. The classical tuning approach for these controllers is based on specifying a certain gain crossover frequency, a phase margin and a robustness to gain variations. To tune the fractional order controllers, the modulus, phase and phase slope of the process at the imposed gain crossover frequency are required. Usually these values are obtained from a mathematical model of the process, e.g. a transfer function. In the absence of such model, an auto-tuning method that is able to estimate these values is a valuable alternative. Auto-tuning methods are among the least discussed design methods for fractional order PID controllers. This paper proposes a novel approach for the auto-tuning of fractional order controllers. The method is based on a simple experiment that is able to determine the modulus, phase and phase slope of the process required in the computation of the controller parameters. The proposed design technique is simple and efficient in ensuring the robustness of the closed loop system. Several simulation examples are presented, including the control of processes exhibiting integer and fractional order dynamics.
IMC Based Fractional Order Controller for Three Interacting Tank ProcessTELKOMNIKA JOURNAL
In model based control, performance of the controlled plant considerably depends on the
accuracy of real plant being modelled. In present work, an attempt has been made to design Internal
Model Control (IMC), for three interacting tank process for liquid level control. To avoid complexities in
controller design, the third order three interacting tank process is modelled to First Order Plus Dead Time
(FOPDT) model. Exploiting the admirable features of Fractional Calculus, the higher order model is also
modelled to Fractional Order First Order Plus Dead Time (FO-FOPDT) model, which further reduces the
modelling error. Moving to control section, different IMC schemes have been proposed based on the order
of filter. Various simulations have been performed to show the greatness of Fractional order modelled
system & fractional order filters over conventional integer order modelled system & integer order filters
respectively. Both for parameters estimation of reduced order model and filter tuning, Genetic Algorithm
(GA) is being applied.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
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Model-based Approach of Controller Design for a FOPTD System and its Real Time Implementation
1. IOSR Journal of Electrical and Electronics Engineering (IOSR-JEEE)
e-ISSN: 2278-1676,p-ISSN: 2320-3331, Volume 8, Issue 6 (Nov. - Dec. 2013), PP 21-26
www.iosrjournals.org
www.iosrjournals.org 21 | Page
Model-based Approach of Controller Design for a FOPTD
System and its Real Time Implementation
Anil Kumar Sharma
Dept. of Applied Electronics and Instrumentation Engineering, A.I.E.M, Mogra, India
Abstract: For SISO (single-input-single-output) models typically used in the process plants, the Internal Model
Control (IMC) is shown to supersede the conventional PID controllers and also it becomes much easier to tune
than are controllers in a standard feedback control structure. The conventional PID controllers are used in the
process plants to a large extent due to their simple structure and its implementation is also easy. A tuning
method based on IMC-PID is proposed for stable FOPTD systems. The IMC-PID controller provides a better
trade-off between closed loop performance and robustness to model uncertainties with a single tuning
parameter. Performance of the controller is evaluated through simulation study as well as from experimental
verification on a level process.
Keywords: Feedback control, FOPTD, internal model control (IMC), process model, process reaction curve.
I. Introduction
Model-based approach is one type of approach in which once the model of the process is known to us
we can approximate the controller. A great deal of work that has provided tuning rules on model-based approach
based on frequency and time domain approaches have been reported at different time. In the year 1942, Ziegler
and Nichols [1] developed tuning parameters which was published in the paper, “Optimum Settings for
Automatic Controllers”. These tuning rules were based on process reaction curve method. Tuning rules that
have been reported by Cohen and Coon [2], Astrom Hagglund [3] and Tyreus and Luyben [4] were also based
on process reaction curve method. Thereafter, Garcia, C.E.; and Morari, M [5] worked on Internal model
Control and published a paper, “Internal Model Control I. A Unifying Review and Some Results”. Because of
the popularity of model-based PID tuning methods, Morari, M; along with Rivera, D.E.; and Skogestad, S.; [6]
continued to work upon model-based controller design and published a paper, “Internal Model Control.4. PID
Controller Design”, in the year 1986. Afterwards, model-based approaches became popular among the
researches who were engaged in designing of controllers.
A more comprehensive model-based design method, Internal Model Control (IMC), was developed
by Morari and coworkers (Garcia and Morari, 1982; Rivera et al., 1986). Internal Model Control (IMC)
method is based on an assumed process model (embedded in the controller) and leads to analytical
expressions for the controller settings. The IMC approach has the advantage that it allows model uncertainty
and tradeoffs between performance and robustness to be considered in a more systematic fashion [7]. Internal
Model control technique is a simple and powerful control structure based on assumed process model and relates
the controller settings to the model parameters in a straight forward manner. It explicitly takes into account
model uncertainty. It allows the designer to trade-off control system performance against control system
robustness to process changes and modeling errors. It provides time-delay compensation. The controller can be
used to shape both input tracking and disturbance rejection responses. Perfect tracking is achieved despite
model-mismatch, as long as the controller is the perfect inverse of the model [8]. IMCs are much easier to
tune than the controllers in a standard feedback control system. Although the IMC design procedure is
identical to the open-loop control design procedure, the implementation of IMC results in a feedback
system.
In the year 2008, Panda, R.C. [9] reported synthesis of PID tuning rules based on the desired closed-
loop response. In this paper, Panda simplified an expression for the true controller, which contains a time-delay
term, using a power series to approximate its value. This true controller is finally rearranged in a suitable
manner such that an ideal PID controller is obtained. Because of very good disturbance rejection and set-point
tracking capability, Internal Model Control method become very popular to the control engineers and
researchers and work on Internal Model Control is still going on.
II. Mathematical Approach Of IMC Design
The IMC design procedure is similar to the design procedure that we developed for open-loop
controller design earlier. The assumptions we are making is that the model is perfect i.e.,
The IMC design procedure consists of the following four steps:
2. Model-based Approach of Controller Design for a FOPTD System and its Real Time Implementation
www.iosrjournals.org 22 | Page
1. Factor the process model into invertible (“good stuff”) and noninvertible (“bad stuff”- time delays and
RHP zeros) elements.
)(~)(~)(~ sgsgsg ppp . ……………… (2.1)
This factorization is performed so that the resulting controller will be stable.
2. Form the idealized IMC controller. The ideal internal model controller is the inverse of the invertible
portion of the process model.
)(~)(~ 1
sgsq p
……………………… (2.2)
3. Add a filter to make the controller proper. A transfer function is proper if the order of the denominator
polynomial is at least as high as the numerator polynomial.
)()(~)()(~)( 1
sfsgsfsqsq p
………. (2.3)
If it is most desirable to track step set-point changes, the filter transfer function usually has the form
n
s
sf
1
1
)(
………………… (2.4)
and n is chosen to make the controller proper (or semi proper). If it is most desirable to track ramp set-point
changes (often used for batch reactors or transition control problems), then
n
s
sn
sf
1
1
)(
4. Adjust the filter tuning parameter to vary the speed of response of the closed-loop system. If the λ is
“small”, the closed-loop system is “fast”, if λ is “large”, the closed-loop system is more robust (insensitive to
model error).
If the process model is perfect, then we can write ( ) ( ) ( ) ( ) ………………..(2.5)
Now we can easily calculate what the output response to a set-point change will be. Substituting Eq.(2.2) into
Eq. (2.5) we get
)()()(~)()()()(~)()()()()( 1
srsfsgsgsrsfsqsgsrsqsgsy pppp
………. (2.6)
If the model is perfect, then
)(~)(~)(~)( sgsgsgsg pppp ……………………… (2.7)
and we can substitute Eq. (2.7) into Eq. (2.6) to find
)()()(~)(~)(~)( 1
srsfsgsgsgsy ppp
……………………… (2.8)
which yields
)()()(~)( srsfsgsy p …………………………. (2.9)
Equation (2.9) indicates that the bad stuff must appear in the output response. That is, if the open-loop
process has a RHP zero (inverse response), then the closed-loop system must exhibit inverse response. Also, if
the process has dead time, then dead time must appear in the closed-loop response.
The most common process model is a first-order plus time-delay (FOPTD) transfer function. The
design procedure for such system is shown in the next section. In the following section we show how to
estimate parameters for common simple models. By far the most commonly used model, for control system
design purposes, is the first-order + time delay (FOPTD) model.
III. IMC-Based PID Design For A First Order Plus A Time Delay Process
In the closed loop system a test bench named Feedback Basic Process Rig [38-300] has been used as a
process model. This is a single loop system, using water as the process fluid, which allows study of the
principles of process control using liquid level and flow rates as the process variables to be controlled. The
system consists of a completely self-contained, low pressure flowing water circuit supported on a bench-
mounted panel.
The level control system can be considered as a FOPTD system. The experimental set-up is shown in
Fig. 3.1. The level/flow process control system is a single loop system, using water as the process fluid, which
allows study of the principles of process control using liquid level and flow rates as the process variables to be
controlled.
3.1 Model Identification
For model identification, there are two approaches: Process Reaction Curve method and auto tuning
technique. We will perform this by using the Process Reaction curve method.
3. Model-based Approach of Controller Design for a FOPTD System and its Real Time Implementation
www.iosrjournals.org 23 | Page
3.1.1 Application of process reaction curve method on practical process and identification of actual model:
To get the original process model, we have used the step change method and got a process reaction
curve. For getting the process model from this graph we used two-point method. Applying these methods, we
have estimated the parameters for first-order + time-delay model and get the original process model. Initially,
the process was at a stable condition with a level of height 15 cm in the upper tank. At this point a step change is
applied. Hence, the process reaction curve is obtained and is shown in Fig.3.2.
3.1.2 Results after applying process reaction curve method:
4.0
25100
1545
u
y
kp
Note: Sampling time = 125 msec. So the actual process model transfer function is approximated as
16.4
4.0
)(
75.1
s
e
sg
s
p .
IV. Experimental Study
4.1 Different Tuning Rules: Tuning relations given by Rivera et al., Chien, Lee et al., S. Skogestad and R. C.
Panda are shown in the following table:
0
5
10
15
20
25
30
35
40
45
50
1 14 27 40 53 66 79 92 105 118 131 144 157 170 183 196 209
Paper Selection of λ
Rivera et
al,
1986
( )
Float Level
Transmitter
Display
Unit
Process
Interface
Process
Controller
Dual compartment
tank with Float
type Level Sensor
Sump Tank with
submersible
circulating pump
Servo
Valve
Pulse Flow
Sensor
Sump Tank with
submersible
circulating pump
Visual
Flow
Meter
Pneumatic
Signal Flow
Path
Water
Flow
Path
Electrical
Signal Flow
Path
Functional layout of level/flow process
Fig.3.1. Picture of Level/Flow process rig
Fig. 3.2 Obtained Process Reaction Curve
4. Model-based Approach of Controller Design for a FOPTD System and its Real Time Implementation
www.iosrjournals.org 24 | Page
β is a parameter and selection of β is based on the following rule:
( ) ( ), where α is a constant( ).
RESPONSE OF IMC-PID CONTROLLER (RIVERA ET AL., 1986)
RESPONSE OF IMC-PID CONTROLLER (CHIEN, 1990)
RESPONSE OF IMC-PID CONTROLLER (LEE ET AL., 1998)
RESPONSE OF IMC-PID CONTROLLER (SKOGESTAD, 2003)
Chien,
1990 ( )
- -
Lee et al,
1998
)(
p
i
K )(2
2
p
3)(2
2
i
i
8.0
1.0
p
S.
Skogestad,
2003 )(
pK
)](4,min[ p
- -
R. C.
Panda,
2008 )(
p
i
K )(2
)(
2
p
i
p
i
i
3
)(
)(2
2
)7.1
,2.0max(
p
5. Model-based Approach of Controller Design for a FOPTD System and its Real Time Implementation
www.iosrjournals.org 25 | Page
RESPONSE OF IMC-PID CONTROLLER (R. C. PANDA, 2008)
4.2 Comparison Of Different Tuning Rules
Name Rise time
(sec)
Settling time
(sec)
% OS IAE ITAE
Rivera 6.81 15.38 2.45 3.00 10.35
Chien et al. 3.69 12.26 5.79 11.42 157.2
Lee et al. 5.84 10.33 1.23 3.81 13.06
Skogestad 5.77 12.20 4.5 3.80 12.70
R. C. Panda 14.41 17.73 0.29 4.71 19.61
4.3 Qualitative Performance Of Different Tuning Rules:
V. Conclusion
This work is based on Level Control System. In our work we have done two parts, i.e., process
modeling or model identification and tuning of controllers with Internal Model Control method. For model
identification we have used process reaction curve method by which we have got the process model. Finally, for
tuning approach, we have used Internal Model Control method and have tried to find out the most acceptable
and suitable tuning rules among few standard rules for this Level/Flow Process as well as SIMULINK. We have
identified the process model using the process reaction curve method though we can use other methods like
relay auto-tuning method and ultimate cycle method. A comparative study is made with recently reported model
based tuning schemes. For simplicity first-order + time-delay model has been considered and also such model is
a better approximation for many process plants.
Name Rise time
(sec)
Settling time
(sec)
% OS IAE ITAE
Rivera Medium Large Small Small Medium
Chien et al. Small Medium Medium Medium Large
Lee et al. Medium Medium Small Small Medium
Skogestad Medium Medium Medium Small Medium
R. C. Panda Medium Large Very Small Small Medium
6. Model-based Approach of Controller Design for a FOPTD System and its Real Time Implementation
www.iosrjournals.org 26 | Page
Acknowledgements
The idea for such a paper arose from discussion with Dr. Chanchal Dey, Asst. Professor, Dept. of
Applied Physics, University of Calcutta. He stimulated my interest in controller design. A great thanks to Amit
Kumar Sharma, Jr. Engineer, Eastern Railway for his support.
References
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[3] Astrom, K. J.; Hagglund, T. PID Controllers: Theory, Design and Tuning, 2nd Edition; International Society for Measurement and
Controls: Research Triangle Park, NC, 1995.
[4] Tyreus, B. D.; Luyben, W. L. Tuning PI Controllers for Integrator/Dead Time Processes. Ind. Eng. Chem. Res. 1992, 32, 2625.
[5] Garcia, C. E.; Morari, M. Internal Model Control I. A Unifying Review and Some New Results, Ind. Eng. Chem. Process Des. Dev.,
1982, 21,308.
[6] Rivera, D. E.; Morari, M.; Skogestad, S. Internal Model Control, 4. PID controller design. Ind. Eng. Proc. Des. Dev. 1986, 25, 252.
[7] Seborg, D. E.; Edgar, T. F.; Mellichamp, D. A. Process Dynamics and Control, Second Edition; John Wiley and Sons: New York,
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[8] Bequette. B. W., Process Control Modeling, Design and Simulation, Pearson Education, Inc., New Jersey, 2003.
[9] Panda, R. C. Synthesis of PID Tuning Rule Using the Desired Closed-Loop Response. Ind. Eng. Chem. Res. 2008, 47, 8684-8692.
Anil Kumar Sharma is working as an Assistant Professor in the department of Applied
Electronics and Instrumentation Engineering, Abacus Institute of Engineering and Management,
Mogra, Hooghly. He obtained his M.Tech in Instrumentation and Control Engineering from the
department of Applied Physics, University of Calcutta. His area of research includes Intelligent
Process Control, Biomedical Instrumentation, Control System and Signal Processing.
E-mail: anil_0181@yahoo.com