Balkan Journal of Electrical and Computer Engineering, 2020
A positive zero in the transfer function of a process causes an initial response in opposite to t... more A positive zero in the transfer function of a process causes an initial response in opposite to the final steady-state. This characteristic is known as inverse response and makes the control more challenging. In the literature, usually, well known tree term controllers, that is, Proportional-Integral-Derivative (PID) controllers, are used to control such processes. In this paper, simple analytical expressions have been derived to find optimum tuning parameters of I-PD controllers to control open loop stable processes with time delay and a positive zero. Time weighted versions of Integral of Squared Error (ISE) criterion, namely ISTE, IST2E and IST3E criteria, which have been proved to be resulting in quite satisfactory closed loop responses, have been used to derive optimum tuning rules. Effectiveness of obtained tuning rules has been shown by simulation examples.
UKACC International Conference on Control (CONTROL '98)
ABSTRACT The paper introduces the A-locus method which is an exact method for limit cycle investi... more ABSTRACT The paper introduces the A-locus method which is an exact method for limit cycle investigation in relay controlled loops for parameter estimation for stable FOPDT and SOPDT transfer functions. The method has also been extended to unstable FOPDT and SOPDT transfer functions since it is possible to have unstable plant models for some chemical processes. The method gives two advantages. First, the steady-state gain can be calculated from the relay feedback test. Secondly, all parameters of a SOPDT transfer function can be obtained, using only one relay test. The obtained parameters are exact if there are no measurement errors or disturbances
ABSTRACT Good control of processes with a long dead time is often achieved using a Smith predicto... more ABSTRACT Good control of processes with a long dead time is often achieved using a Smith predictor structure. Typically a PI or PID controller is used in this configuration. In this paper, controller design is considered for a recently proposed modified form of the Smith predictor. The design is done using the Coefficient Diagram Method (CDM) to achieve a good step response to a set point change. The proposed method is compared with some other existing methods to illustrate its value.
2019 International Conference on Applied Automation and Industrial Diagnostics (ICAAID), 2019
TRMS is a nonlinear system which resembles a dynamic of a helicopter with a strong coupling effec... more TRMS is a nonlinear system which resembles a dynamic of a helicopter with a strong coupling effect between main and tail rotors. Generally speaking, the simplicity of the linear PID has tempted the control engineers to use it for controlling the nonlinear systems. However, the linear PID controller could not sufficiently handle these systems particularly in terms of producing a fast response with a small overshoot. Therefore, a new nonlinear PID based on the dynamic of biological cell membrane potentials has been proposed to alleviate the overshoot effect with insuring a small tracking error. The parameters of suggested controller have been tuned by using DE algorithm. The simulation and experimental results have illustrated the superior performance of proposed nonlinear controller compared to a linear PID.
2019 International Conference on Applied Automation and Industrial Diagnostics (ICAAID), 2019
Several methods, which have been suggested for tuning PI controller parameters by obtaining the c... more Several methods, which have been suggested for tuning PI controller parameters by obtaining the centroid of the stability boundary locus, can be found in the literature. However, all those methods rely on graphical plottings which are time consuming. Here, a new analytical approach is introduced to find centroid of the stability region for PI controllers to control time delay integrating processes. For this purpose, it is assumed that time delay integrating process can be modelled by integrating plus first order plus dead-time (IFOPDT) model. The suggested method cancels the necessity of plotting the stability region. Simulation examples were performed to ensure the efficiency of the suggested method.
2019 International Conference on Applied Automation and Industrial Diagnostics (ICAAID), 2019
Processes exhibiting an initial response in opposite to the final steady-state are known as inver... more Processes exhibiting an initial response in opposite to the final steady-state are known as inverse response processes which make the control more difficult. In the literature, usually, well known tree term controllers, that is Proportional-Integral-Derivative (PID) controllers, are used to control such processes. This paper introduces optimal tuning rules for I-PD controllers, which has been shown to perform better than PID controllers, for controlling integrating processes with inverse response. Integral performance criteria were applied to obtain those mentioned tuning rules to be used for calculating the I-PD controller tuning parameters. Effectiveness of obtained tuning rules has been shown by simulation examples.
2018 6th International Conference on Control Engineering & Information Technology (CEIT), 2018
Applications of the fractional calculus have recently found a wide area in control theory by mean... more Applications of the fractional calculus have recently found a wide area in control theory by means of the advantages fractional derivative order and fractional integrator order provide. As a result, the importance of designing a better fractional-order controller to satisfy the conditions has increased. Because of the difficulties in designing fractional-order controller in the time domain, generally, the frequency domain is used to design controller. Frequency domain parameters as phase margin, gain margin, phase crossover frequency and gain crossover frequency are generally used for designing of the controllers. This paper represents a solution to obtain stability regions to stabilize a first order unstable system plus dead time with fractional-order proportional integrating (PI) controller and aims to show the effects of fractional integrator order, phase margin, and time delay on stability areas by obtaining different stability regions for different fractional integrator order, ...
2017 10th International Conference on Electrical and Electronics Engineering (ELECO), 2017
Many PI and/or PID design methods can be found in the literature for controlling open loop stable... more Many PI and/or PID design methods can be found in the literature for controlling open loop stable processes. However, less PID design methods for controlling unstable processes are considered. Hence, this paper introduces simple and optimal tuning rules for controlling unstable time delay systems. Design method requires a model of the actual process. Here, an unstable first order plus dead time (UFOPDT) model has been used. Based on the UFOPDT model, optimal analytical expressions have been obtained using the ISTE and IST2E criteria, well-known integral performance indexes. Simulation examples are provided to show the use of the obtained tuning rules.
2018 6th International Conference on Control Engineering & Information Technology (CEIT), 2018
Unstable processes are frequently encountered in industrial applications. Proportional-Integral-D... more Unstable processes are frequently encountered in industrial applications. Proportional-Integral-Derivative (PID) controllers are the most widespread used controllers for controlling unstable processes. However, it has been shown that PID controllers perform unsatisfactorily for controlling unstable processes. Therefore, this study reports on the use of I-PD controllers for improving closed loop performances of unstable processes. Optimal and analytical tuning rules have been derived to calculate tuning parameters of the I-PD controller. Simulation results, giving comparisons of some existing PID and I-PD design methods to control open loop unstable processes, have been supplied to illustrate superior closed loop performance of the proposed optimal and analytical I-PD design approach.
Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering, 2021
The simplicity of the proportional-integral controller makes it very popular in many practical en... more The simplicity of the proportional-integral controller makes it very popular in many practical engineering applications. In the literature, several approaches have been introduced for tuning proportional-integral controllers by calculating the centroid of the stability region. However, all those approaches depend on graphical plottings which are time-consuming. Also, the design procedure has to be redone as the transfer function changes. Here, two new analytical methods are proposed to obtain the centroid of the stability region for the proportional-integral controllers to control a time delay process which can be modeled by a stable or unstable first-order plus dead-time model. The methods introduced eliminate the compulsory procedure of plotting the stability region. The efficiency of the suggested methods has been studied by conducting a robustness analysis and studying several simulation examples.
Transactions of the Institute of Measurement and Control, 1999
Exact expressions for the periods and amplitudes of limit cycles in relay controlled loops, with ... more Exact expressions for the periods and amplitudes of limit cycles in relay controlled loops, with first order plus dead time (FOPDT) and second order plus dead time (SOPDT) transfer functions have been obtained using the A-locus method. The method has also been extended to unstable FOPDT and SOPDT transfer functions since it is possible to have unstable transfer function models for some chemical processes. For these processes, it is shown that analysis using the DF method can give large errors. Several examples have been given to illustrate application of the method and it has been shown that the method will work well for small measurement errors when compared with the DF method.
Balkan Journal of Electrical and Computer Engineering, 2020
A positive zero in the transfer function of a process causes an initial response in opposite to t... more A positive zero in the transfer function of a process causes an initial response in opposite to the final steady-state. This characteristic is known as inverse response and makes the control more challenging. In the literature, usually, well known tree term controllers, that is, Proportional-Integral-Derivative (PID) controllers, are used to control such processes. In this paper, simple analytical expressions have been derived to find optimum tuning parameters of I-PD controllers to control open loop stable processes with time delay and a positive zero. Time weighted versions of Integral of Squared Error (ISE) criterion, namely ISTE, IST2E and IST3E criteria, which have been proved to be resulting in quite satisfactory closed loop responses, have been used to derive optimum tuning rules. Effectiveness of obtained tuning rules has been shown by simulation examples.
UKACC International Conference on Control (CONTROL '98)
ABSTRACT The paper introduces the A-locus method which is an exact method for limit cycle investi... more ABSTRACT The paper introduces the A-locus method which is an exact method for limit cycle investigation in relay controlled loops for parameter estimation for stable FOPDT and SOPDT transfer functions. The method has also been extended to unstable FOPDT and SOPDT transfer functions since it is possible to have unstable plant models for some chemical processes. The method gives two advantages. First, the steady-state gain can be calculated from the relay feedback test. Secondly, all parameters of a SOPDT transfer function can be obtained, using only one relay test. The obtained parameters are exact if there are no measurement errors or disturbances
ABSTRACT Good control of processes with a long dead time is often achieved using a Smith predicto... more ABSTRACT Good control of processes with a long dead time is often achieved using a Smith predictor structure. Typically a PI or PID controller is used in this configuration. In this paper, controller design is considered for a recently proposed modified form of the Smith predictor. The design is done using the Coefficient Diagram Method (CDM) to achieve a good step response to a set point change. The proposed method is compared with some other existing methods to illustrate its value.
2019 International Conference on Applied Automation and Industrial Diagnostics (ICAAID), 2019
TRMS is a nonlinear system which resembles a dynamic of a helicopter with a strong coupling effec... more TRMS is a nonlinear system which resembles a dynamic of a helicopter with a strong coupling effect between main and tail rotors. Generally speaking, the simplicity of the linear PID has tempted the control engineers to use it for controlling the nonlinear systems. However, the linear PID controller could not sufficiently handle these systems particularly in terms of producing a fast response with a small overshoot. Therefore, a new nonlinear PID based on the dynamic of biological cell membrane potentials has been proposed to alleviate the overshoot effect with insuring a small tracking error. The parameters of suggested controller have been tuned by using DE algorithm. The simulation and experimental results have illustrated the superior performance of proposed nonlinear controller compared to a linear PID.
2019 International Conference on Applied Automation and Industrial Diagnostics (ICAAID), 2019
Several methods, which have been suggested for tuning PI controller parameters by obtaining the c... more Several methods, which have been suggested for tuning PI controller parameters by obtaining the centroid of the stability boundary locus, can be found in the literature. However, all those methods rely on graphical plottings which are time consuming. Here, a new analytical approach is introduced to find centroid of the stability region for PI controllers to control time delay integrating processes. For this purpose, it is assumed that time delay integrating process can be modelled by integrating plus first order plus dead-time (IFOPDT) model. The suggested method cancels the necessity of plotting the stability region. Simulation examples were performed to ensure the efficiency of the suggested method.
2019 International Conference on Applied Automation and Industrial Diagnostics (ICAAID), 2019
Processes exhibiting an initial response in opposite to the final steady-state are known as inver... more Processes exhibiting an initial response in opposite to the final steady-state are known as inverse response processes which make the control more difficult. In the literature, usually, well known tree term controllers, that is Proportional-Integral-Derivative (PID) controllers, are used to control such processes. This paper introduces optimal tuning rules for I-PD controllers, which has been shown to perform better than PID controllers, for controlling integrating processes with inverse response. Integral performance criteria were applied to obtain those mentioned tuning rules to be used for calculating the I-PD controller tuning parameters. Effectiveness of obtained tuning rules has been shown by simulation examples.
2018 6th International Conference on Control Engineering & Information Technology (CEIT), 2018
Applications of the fractional calculus have recently found a wide area in control theory by mean... more Applications of the fractional calculus have recently found a wide area in control theory by means of the advantages fractional derivative order and fractional integrator order provide. As a result, the importance of designing a better fractional-order controller to satisfy the conditions has increased. Because of the difficulties in designing fractional-order controller in the time domain, generally, the frequency domain is used to design controller. Frequency domain parameters as phase margin, gain margin, phase crossover frequency and gain crossover frequency are generally used for designing of the controllers. This paper represents a solution to obtain stability regions to stabilize a first order unstable system plus dead time with fractional-order proportional integrating (PI) controller and aims to show the effects of fractional integrator order, phase margin, and time delay on stability areas by obtaining different stability regions for different fractional integrator order, ...
2017 10th International Conference on Electrical and Electronics Engineering (ELECO), 2017
Many PI and/or PID design methods can be found in the literature for controlling open loop stable... more Many PI and/or PID design methods can be found in the literature for controlling open loop stable processes. However, less PID design methods for controlling unstable processes are considered. Hence, this paper introduces simple and optimal tuning rules for controlling unstable time delay systems. Design method requires a model of the actual process. Here, an unstable first order plus dead time (UFOPDT) model has been used. Based on the UFOPDT model, optimal analytical expressions have been obtained using the ISTE and IST2E criteria, well-known integral performance indexes. Simulation examples are provided to show the use of the obtained tuning rules.
2018 6th International Conference on Control Engineering & Information Technology (CEIT), 2018
Unstable processes are frequently encountered in industrial applications. Proportional-Integral-D... more Unstable processes are frequently encountered in industrial applications. Proportional-Integral-Derivative (PID) controllers are the most widespread used controllers for controlling unstable processes. However, it has been shown that PID controllers perform unsatisfactorily for controlling unstable processes. Therefore, this study reports on the use of I-PD controllers for improving closed loop performances of unstable processes. Optimal and analytical tuning rules have been derived to calculate tuning parameters of the I-PD controller. Simulation results, giving comparisons of some existing PID and I-PD design methods to control open loop unstable processes, have been supplied to illustrate superior closed loop performance of the proposed optimal and analytical I-PD design approach.
Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering, 2021
The simplicity of the proportional-integral controller makes it very popular in many practical en... more The simplicity of the proportional-integral controller makes it very popular in many practical engineering applications. In the literature, several approaches have been introduced for tuning proportional-integral controllers by calculating the centroid of the stability region. However, all those approaches depend on graphical plottings which are time-consuming. Also, the design procedure has to be redone as the transfer function changes. Here, two new analytical methods are proposed to obtain the centroid of the stability region for the proportional-integral controllers to control a time delay process which can be modeled by a stable or unstable first-order plus dead-time model. The methods introduced eliminate the compulsory procedure of plotting the stability region. The efficiency of the suggested methods has been studied by conducting a robustness analysis and studying several simulation examples.
Transactions of the Institute of Measurement and Control, 1999
Exact expressions for the periods and amplitudes of limit cycles in relay controlled loops, with ... more Exact expressions for the periods and amplitudes of limit cycles in relay controlled loops, with first order plus dead time (FOPDT) and second order plus dead time (SOPDT) transfer functions have been obtained using the A-locus method. The method has also been extended to unstable FOPDT and SOPDT transfer functions since it is possible to have unstable transfer function models for some chemical processes. For these processes, it is shown that analysis using the DF method can give large errors. Several examples have been given to illustrate application of the method and it has been shown that the method will work well for small measurement errors when compared with the DF method.
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Papers by Ibrahim Kaya