Advances in Parallel & Distributed Processing, and Applications
It is shown that the Smith predictor is a subclass of the Youla-parameterization based generic tw... more It is shown that the Smith predictor is a subclass of the Youla-parameterization based generic two-degree-of-freedom controllers. Comparing the algorithms, the application of the new approach is suggested.
Three different approaches in control design are considered, which correspond to different contro... more Three different approaches in control design are considered, which correspond to different control structures: (1) feedback controller with filtering of the reference signal, (2) twodegree-of-freedom internal model control and (3) generic control scheme. It is shown that all these structures are equivalent if the control aim e.g., the tracking and the disturbance rejection behaviors, respectively, are the same in the three cases. Also inverse unstable and dead time processes are dealt with.
2020 IEEE 16th International Conference on Control & Automation (ICCA)
The PFC (Predictive Functional Control) algorithm is a very effective predictive controller with ... more The PFC (Predictive Functional Control) algorithm is a very effective predictive controller with controller parameters having a physical meaning. The equivalence of PFC to PI and PID controllers with Smith predictor is shown for delayed first-, second- and higher-order process models. PI(D) controllers are tuned based on the equivalent PFC algorithms. Temperature control of a hot air blower pilot plant illustrates the proposed tuning method.
In a practical control system the process always has a time delay. The uncertainty in the knowled... more In a practical control system the process always has a time delay. The uncertainty in the knowledge of the time delay i.e. the delay mismatch strongly influences the quality of the closed-loop control. It can cause unwanted instability and influences the robustness of the control. Stability region applicable for this uncertainty is investigated in this paper in connection with the required performance and robustness.
Systems and control are all around us. System view, understanding systems and how they are contro... more Systems and control are all around us. System view, understanding systems and how they are controlled is important for everyone. The behavior of systems is determined by some fundamental principles which can be understood by everyone. The main principles governing systems and control are presented on different levels. The first level is dedicated for everyone. Comics-like interpretation is provided with explanations. The second level discusses the main topics dedicated for the interested students. Several case studies demonstrate how system view is considered in different areas of life. With this approach systems in different areas of life could be better understood contributing to better decisions influencing their performance. The third level provides deeper insight into some aspects of modern mathematical system theory, to geometric view of control systems. The material is available on a website on the internet.
Three different approaches in control design are considered, which correspond to different contro... more Three different approaches in control design are considered, which correspond to different control structures: (1) feedback controller with filtering of the reference signal, (2) two-degree-of-freedom internal model control and (3) generic control scheme. It is shown that all these structures are equivalent if the control aim e.g., the tracking and the disturbance rejection behaviors, respectively, are the same in the three cases. Also inverse unstable and dead time processes are dealt with.
Advanced Textbooks in Control and Signal Processing, 2018
Nowadays more and more digital computers working in real time are used to perform main tasks of a... more Nowadays more and more digital computers working in real time are used to perform main tasks of a control system. The output of the process is sampled and the digitalized values are forwarded to the computer via A/D (Analog/Digital) converters. The computer calculates the control signal in each sampling instant and forwards it to the process input via D/A (Digital/Analog) converter. Several digital control algorithms can be applied to ensure the required performance of the control system. Description and analysis of sampled systems is discussed in the time, the z-operator and the frequency domains.
Polynomial design is an important method of regulator design. The main idea is that the transfer ... more Polynomial design is an important method of regulator design. The main idea is that the transfer function of the closed loop control system is prescribed as the aim of the control, then the regulator is calculated using the knowledge about the process. The controller design is executed by solving a Diophantine equation. The method can be applied in case of sampled data control as well. Control of unstable processes and processes with dead time can also be realized.
Discrete unstable systems and systems containing dead time can be stabilized and controlled using... more Discrete unstable systems and systems containing dead time can be stabilized and controlled using the general polynomial method which is based on the solution of a Diophantine equation. Some features of the method are presented.
Youla parameterization is an effective method to control stable processes. The controller is desi... more Youla parameterization is an effective method to control stable processes. The controller is designed in open loop to provide good reference signal tracking. Extending the structure with IMC–Internal Model Control disturbance rejection is ensured. Application of this method is shown.
In computer control a sampled data system can be controlled by a digital control algorithm realiz... more In computer control a sampled data system can be controlled by a digital control algorithm realized by a computer program executed in real time. Several discrete control algorithms as Youla parameterized controller, Smith predictor controller, dead-beat controller, the idea of predictive controller are discussed and their properties are analyzed.
Advances in Parallel & Distributed Processing, and Applications
It is shown that the Smith predictor is a subclass of the Youla-parameterization based generic tw... more It is shown that the Smith predictor is a subclass of the Youla-parameterization based generic two-degree-of-freedom controllers. Comparing the algorithms, the application of the new approach is suggested.
Three different approaches in control design are considered, which correspond to different contro... more Three different approaches in control design are considered, which correspond to different control structures: (1) feedback controller with filtering of the reference signal, (2) twodegree-of-freedom internal model control and (3) generic control scheme. It is shown that all these structures are equivalent if the control aim e.g., the tracking and the disturbance rejection behaviors, respectively, are the same in the three cases. Also inverse unstable and dead time processes are dealt with.
2020 IEEE 16th International Conference on Control & Automation (ICCA)
The PFC (Predictive Functional Control) algorithm is a very effective predictive controller with ... more The PFC (Predictive Functional Control) algorithm is a very effective predictive controller with controller parameters having a physical meaning. The equivalence of PFC to PI and PID controllers with Smith predictor is shown for delayed first-, second- and higher-order process models. PI(D) controllers are tuned based on the equivalent PFC algorithms. Temperature control of a hot air blower pilot plant illustrates the proposed tuning method.
In a practical control system the process always has a time delay. The uncertainty in the knowled... more In a practical control system the process always has a time delay. The uncertainty in the knowledge of the time delay i.e. the delay mismatch strongly influences the quality of the closed-loop control. It can cause unwanted instability and influences the robustness of the control. Stability region applicable for this uncertainty is investigated in this paper in connection with the required performance and robustness.
Systems and control are all around us. System view, understanding systems and how they are contro... more Systems and control are all around us. System view, understanding systems and how they are controlled is important for everyone. The behavior of systems is determined by some fundamental principles which can be understood by everyone. The main principles governing systems and control are presented on different levels. The first level is dedicated for everyone. Comics-like interpretation is provided with explanations. The second level discusses the main topics dedicated for the interested students. Several case studies demonstrate how system view is considered in different areas of life. With this approach systems in different areas of life could be better understood contributing to better decisions influencing their performance. The third level provides deeper insight into some aspects of modern mathematical system theory, to geometric view of control systems. The material is available on a website on the internet.
Three different approaches in control design are considered, which correspond to different contro... more Three different approaches in control design are considered, which correspond to different control structures: (1) feedback controller with filtering of the reference signal, (2) two-degree-of-freedom internal model control and (3) generic control scheme. It is shown that all these structures are equivalent if the control aim e.g., the tracking and the disturbance rejection behaviors, respectively, are the same in the three cases. Also inverse unstable and dead time processes are dealt with.
Advanced Textbooks in Control and Signal Processing, 2018
Nowadays more and more digital computers working in real time are used to perform main tasks of a... more Nowadays more and more digital computers working in real time are used to perform main tasks of a control system. The output of the process is sampled and the digitalized values are forwarded to the computer via A/D (Analog/Digital) converters. The computer calculates the control signal in each sampling instant and forwards it to the process input via D/A (Digital/Analog) converter. Several digital control algorithms can be applied to ensure the required performance of the control system. Description and analysis of sampled systems is discussed in the time, the z-operator and the frequency domains.
Polynomial design is an important method of regulator design. The main idea is that the transfer ... more Polynomial design is an important method of regulator design. The main idea is that the transfer function of the closed loop control system is prescribed as the aim of the control, then the regulator is calculated using the knowledge about the process. The controller design is executed by solving a Diophantine equation. The method can be applied in case of sampled data control as well. Control of unstable processes and processes with dead time can also be realized.
Discrete unstable systems and systems containing dead time can be stabilized and controlled using... more Discrete unstable systems and systems containing dead time can be stabilized and controlled using the general polynomial method which is based on the solution of a Diophantine equation. Some features of the method are presented.
Youla parameterization is an effective method to control stable processes. The controller is desi... more Youla parameterization is an effective method to control stable processes. The controller is designed in open loop to provide good reference signal tracking. Extending the structure with IMC–Internal Model Control disturbance rejection is ensured. Application of this method is shown.
In computer control a sampled data system can be controlled by a digital control algorithm realiz... more In computer control a sampled data system can be controlled by a digital control algorithm realized by a computer program executed in real time. Several discrete control algorithms as Youla parameterized controller, Smith predictor controller, dead-beat controller, the idea of predictive controller are discussed and their properties are analyzed.
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Papers by Ruth Bars