Tomasz Klopot

Flexible function block implementation of the balance-based adaptive controller as the potential alternative for PID-based industrial applications

This paper deals with the practical aspects of the implementation of the balance-based adaptive control (B-BAC) technique. It gives the simple mathematical background of this methodology, shows the case-independent implementation concept as the ready-to-use flexible function block that results from the B-BAC generality, discusses how to embed the additional functionalities required in professional industrial control applications and finally presents three implementation examples for three different programming and hardware platforms. The control performance of each B-BAC function block is validated experimentally and compared with the performance of the corresponding platform-related standard PID function blocks. The comparative results and the potential accessibility of both the flexible function block and the simple tuning method put forward B-BAC methodology as a strong alternative for PID-based industrial control applications.

Flexible function block for PLC-based implementation of the Balance-Based Adaptive Controller

This paper presents the flexible and ready-to-use function block for the implementation of the Balance-Based Adaptive Controller (B-BAC) embedded in the Siemens S7 PLCs. It is written according to the IEC-61131-3 programming standard using the SIMATIC software package STEP 7. The basic design principles are discussed in terms of ensuring the functionality similar to a PID function block and this functionality allows for direct B-BAC implementation to control a wide variety of different industrial SISO processes. Laboratory experimental tests were carried out in the laboratory water pumping system and the implementation aspects and control results are discussed in the paper.

Comparison of DMC and PFC control for heating process

The paper presents comparison between two popular predictive control algorithms DMC and PFC. General description of both algorithms are presented in details for FOPDT (First Order Plus Dead Time) dynamics. Heating process with heat source and heat exchanger was used as an example control plant for testing both algorithms. Design of controllers and tuning procedures are presented. Results of control and performance tests are included as well as conclusion remarks on practical aspects of implementation of the algorithms.

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.

Metamorphic Controller for Collaborative Design of an Optimal Structure of the Control System

When designing a control system, the customer specifies some control requirements and the expert provides the parameterized optimal controller. A change of the control algorithm to a more advanced one may lead to a better performance of the closed loop system. On the other hand, implementation and parameterization of the advanced controllers require more extensive knowledge. A possible solution is a group of cooperating experts that are able to determine the most suitable control algorithm, depending on the customer’s requirements. However, in practice, hiring more experts is an expensive approach. Hence, the performance of majority of industrial systems is not optimal. The paper presents the metamorphic controller with extended functionality for selection of an optimal control algorithm (including advanced controllers). As a result, only one expert, cooperating with the customer, is sufficient to ensure the optimal system performance. The proposed solution has been implemented and tested on the industrial controller.

Function block practical implementation of Balance-Based Adaptive Control for pH process

This paper deals with the Balance-Based Adaptive Control (B-BAC) of the pH process. The implementation is in the form of the general, flexible and ready-to-use function block written for Allen Bradley® PLC family according to IEC-61131-3 standard. Additionally, the very important aspects of practical implementation are addressed: signal conditioning, bumpless switching, anti-windup action, etc. Experimental results show the functionality of this function block and the superiority of the B-BAC methodology over the conventional PI control in the application to the laboratory pH process.

Adaptive dynamic matrix control with interpolated parameters

The classical (non-adaptive) Dynamic Matrix Control (DMC) algorithm is designed and tuned for a chosen operating point of the nonlinear plant. Hence, the performance of the control system may be deteriorated in a wide range of operating levels. The paper discusses a possibility of using an adaptive Dynamic Matrix Control (DMC) for a hydraulic nonlinear plant. Depending on the current value of the process variable, the idea is to use linear spline interpolation to calculate the controller parameters that appear in the final form of equation for the control increment. As a result, it is possible to reduce the number of necessary calculations. Numerical simulations of the closed-loop system show that the adaptive DMC algorithm ensures satisfactory performance over a wide range of operating levels in comparison to the classical DMC tuned for a single operating point.

Performance evaluation of redundant OPC UA architecture for process control

Classical control applications with a centralized logic and distributed input/output system are being replaced by dynamic environments of cooperating components. Thus, the OPC (Object Linking and Embedding for Process Control) UA (Unified Architecture) is becoming more popular, because the OPC Data Access substandard is not well suited for distributed systems. Moreover, in many production systems, redundant data servers are preferred, for financial and legal reasons. Providing performance evaluation gives an estimate of the time required (and data samples lost) to switch to a backup data source for redundant OPC UA architecture, depending on the failure detection method, number of variables and redundancy mode.

Practical verification of adaptive dynamic matrix control with interpolated parameters

The paper presents the experimental studies of the adaptive dynamic matrix control (DMC) algorithm with interpolated parameters. The idea of adaptation mechanism is to determine the controller parameters that appear in the control law equation for several operating points of the system. In turn, the parameter values between the two consecutive operating points are calculated by using linear spline interpolation. The effectiveness of the adaptive DMC algorithm is studied for the electric flow heater for various number of operating points (interpolation nodes) in the presence of step changes in the set point and mean power of the electric heater. The obtained results show that it is possible to significantly reduce the number of interpolation nodes, while keeping the control system performance at a satisfactory level.

Adaptive and Non-Adaptive Dynamic Matrix Control for Conical Tank

Abstract Conical tanks are widely used in food process industries, hydrometallurgical industries and also in the water treatment industry. Moreover, liquid level control of a conical tank is still challenging for typical process control because of occurred nonlinearities. This paper presents comparison between Adaptive and Non-Adaptive version of popular predictive Dynamic Matrix Control.