Pawel Nowak

Virtual commissioning for the control of the continuous industrial processes — Case study

This paper concentrates on the possibilities of the application of the virtual commissioning procedure for the design and verification of the control systems for the continuous industrial processes. After short review and defining the motivation and recognizing the bottlenecks, the case study is presented. It is based on the laboratory pneumatic setup representing the nonlinear continuous process of the higher relative degree. The stages of its modeling are presented and the potential possibilities of the application of the virtual commissioning for its control are discussed, based on the practical results.

Simplified modeling of plate heat exchangers

In this paper, the simplified modeling of the counter-flow plate heat exchanger is presented. The aim of the work is to propose a relatively simple model useful for the controller design. Dynamical behavior of the plate heat exchanger is modeled by simple double pipe model. Two different methods are used to approximate the partial differential equations. The first one is the finite difference method. The second one is the orthogonal collocation method. Both methods are compared in terms of the modeling accuracy and model complexity.

Simulation validation of the model-based control of the plate heat exchanger with on-line compensation for modelling inaccuracies

This paper describes the stage of initial validation of the model-based control of the plate heat exchanger (PHE) by simulation. For the distributed parameter model of PHE validated on the basis of the measurement data collected from the real process, the approximation by the orthogonal collocation method is applied and then the linearizing controller with the on-line compensation for the potential modelling inaccuracies is suggested. This approach ensures relatively low computational complexity due to the low dimension of the approximating dynamical model, which allows for its practical implementation in the programmable logic controllers. The suggested controller is tested by simulation under the realistic experiments scenario and it shows its superiority and robustness over the conventional PI controller, for both tracking and disturbances rejection. The results show that the suggested concept can be considered as an interesting model-based alternative for the PID-based control systems that are still widely applied in the industrial practice.

Observer-based cascade control of the heat distribution system

In this paper, the cascade control of the supply system for the heat exchanger is presented. The aim of the work is the construction of cascade control system, when the output for the inner loop is not measurable. This signal is reconstructed by using the state observer derived from the distributed parameter model of the heat transportation and its implementation is based on the orthogonal collocation method. The idea is verified by simulation and the results are compared with single loop control system with PI controller.

On potential possibilities of gain and phase margin specifications-oriented robust tuning of Balance-Based Adaptive Controller

In this paper, the potential possibilities of robust tuning of the Balance-Based Adaptive Controller (B-BAC) are discussed in terms of user-defined gain and phase margins. Considering the First Order + Dead Time (FOPDT) process to be controlled and starting from previously suggested simple B-BAC tuning method, the additional tuning parameter is introduced and its influence on the stability boundaries and on the robust tuning region is investigated, in comparison with the conventional PI controller. It is shown that the stability and robust tuning regions are larger for the B-BAController and how the additional tuning parameter can be used for robust retuning of the B-BAController.

Linearizing controller for higher-degree nonlinear processes with compensation for modeling inaccuracies practical validation and future developments

This work shows the results of the practical implementation of the linearizing controller for the example laboratory pneumatic process of the third relative degree. Controller design is based on the Lie algebra framework but in contrast to the previous attempts, the on-line model update method is suggested to ensure offset-free control. The paper details the proposed concept and reports the experiences from the practical implementation of the suggested controller. The superiority of the proposed approach over the conventional PI controller is demonstrated by experimental results. Based on the experiences and the validation results, the possibilities of the potential application of the data-driven soft sensors for further improvement of the control performance are discussed.

Practical verification of active disturbance rejection controller for the pneumatic setup

In this paper, the practical verification of Active Disturbance Rejection Controller (ADRC) implementation for pneumatic setup is investigated. Apart from experimental results, the inverse half-rule is suggested to support ADRC tuning for the second order processes by adjusting the value of the scaling factor. This rule is based only on the approximation of the process step response by First Order plus Dead Time (FOPDT) model. The results show the practical applicability of the suggested tuning method and the superiority of ADRC control performance over the conventional PI controller.

Dynamical aspects of multi-input single-output control for heat distribution processes: Case study

In this paper, the possibility of Multi-Input Single-Output control of the heat distribution processes is investigated. Based on the validated model of the example experimental setup, the static and dynamical properties of the process are investigated and discussed in terms of control performance and efficiency. Two potential manipulating variables are considered and different control strategies are discussed, including control by only single manipulating variable and by the proper and simultaneous adjustment of both of them. The energy efficiency is also considered.

Robust tuning for first-order reduced active disturbance rejection controller

In this paper, the robust tuning method for FirstOrder Active Disturbance Rejection Control based on Reduced-Order Extended State Observer is proposed. Its robustness is ensured by defining gain margin and phase margin constraints and then, for these constraints, the optimal load disturbance rejection is ensured by suggested tuning method in terms of optimal Integral Absolute Error. The D-partition method and virtual gain-phase margin tester is used to determine gain and margin boundaries, while optimization of ADRC tuning parameters is based on Nelder-Mead numerical algorithm. Suggested tuning method is tested by simulation.