Lubos Cirka

A Flexible and Configurable Architecture for Automatic Control Remote Laboratories

In this paper, we propose a novel approach in hardware and software architecture design for implementation of remote laboratories for automatic control. In our contribution, we show the solution with flexible connectivity at back-end, providing features of multipurpose usage with different types of experimental devices, and fully configurable client side application at front-end. The physical setup and communication principles of hardware architecture are based on two types of devices: the programmable logic controllers and industrial network routers. The user interface of client application is designed as a Web page, powered by optimized JavaScript, using the sophisticated on-the-fly content generation. To prove the suitability of the architecture, we compare it with other existing approaches of remote laboratory design. We evaluate their benefits and weaknesses, especially in terms of expense, implementation difficulty, and versatility of usage. In this paper, we also show a detailed example of remote laboratory implementation based on new architecture for thermo-optical educational system and provide three other examples of developed remote laboratories. Evaluation of remote laboratory usage and its benefits is provided to demonstrate the learning value of proposed architecture in education process.

Low-complexity polynomial approximation of explicit MPC via linear programming

This paper addresses the issue of the practical implementation of Model Predictive Controllers (MPC) to processes with short sampling times. Given an explicit solution to an MPC problem, the main idea is to approximate the optimal control law defined over state space regions by a single polynomial of pre-specified degree which, when applied as a state-feedback, guarantees closed-loop stability, constraint satisfaction, and a bounded performance decay. It is shown how to search for such a polynomial by solving a single linear program.

Simplifying the implementation of remote laboratories in educational environments using industrial hardware

In this paper we propose an unconventional approach of remote laboratory development based on industrial hardware. We show that it can significantly reduce implementation effort required for deployment of online labs in control education environment. The hardware architecture of laboratory is based on two devices: a programmable logic controller and an industrial router device, which provide the communication and management capabilities between users and experiments. Using these, we were able to develop operationally effective on-line laboratory for remote control of educational experimental plant in the different way that can be seen in traditional approaches based on standard server computers. On this architecture, we have developed the instance of remote laboratory with highly versatile user interface, based on common Web technologies and powered by optimized JavaScript logic. To prove the architecture suitability, we show the practical case of remote laboratory implementation for control education purposes. In section II, we describe the hardware architecture. In section III, the principles of communication between clients and experiment are given. Overview of laboratory is shown in Section IV and security issues are discussed in section V. An example of experimental usage from students point of view is given in the last section of paper.

H 2 optimal controller with integral action for a chemical reactor

This paper deals with H2 control of a continuous stirred tank reactor (CSTR). The coolant temperature and the temperature in the reactor are respectively considered as control and controlled variables. A connection between H2 polynomial approach and the mixed sensitivity optimization for feedback control of CSTR is presented. The control algorithm has been implementedwith the help of the Polynomial Toolbox for MATLAB. The resulting controller has integral action. Simulation results demonstrate the robustness properties of H2 control of CSTR.

Virtual and remote laboratories in education process at FCFT STU

This paper describes the progress in the development of virtual and remote laboratories at Department of Information Engineering and Process Control, FCFT STU in Bratislava. Article is the overview of technical solutions used for online education purposes. These comprise software technologies, most commonly used in virtual and remote laboratory design at our department, as MATLAB Web Server, Java, C/C++, and Adobe Flash. We have created virtual laboratories as online Web applications, which provide features of mathematical computing and simulations of technological plants. We also describe a technology of remote control laboratory with a real experimental device.

Robust adaptive minimum-time control of Piecewise Affine systems

This paper illustrates how an adaptive model predictive controller for the class of hybrid systems affected by parametric uncertainties can be synthesized. Specifically, we investigate the case where the hybrid system is modeled as a piecewise affine (PWA) system where certain elements of the PWA state-update matrices are expressed as symbolic parameters with unknown, but bounded values. For such parametric uncertain PWA systems we show that the control law can be constructed in a way such that all system states are pushed towards a pre-defined target set in the minimal possible number of time steps for all possible realizations of the uncertainty. The robust minimum-time control problem is solved using parametric programming techniques which leads the control law in a form of a look-up table. We illustrate that if the values of the parameters (unknown at the time of the synthesis of the control law) are measured on-line, the resulting feedback policy guarantees time-optimal convergence of the systems states towards a chosen terminal set.

WebPIDDESIGN for robust PID controller design

The paper presents the novel online tool for robust PID controller design RobCont that enables to design robust PID controllers and to analyze the stability of the closed-loop control performance in an advanced way. This tool is an extension of modular system WebPIDDESIGN, a complex framework that provides features of system identification, PID controller design, and evaluation of control quality. RobCont extends the possibilities of framework by control design tasks focused on systems with interval uncertainties. The tool allows user to perform the step-by-step procedure from system definition, through open loop analysis, to selection of robust controller, closed loop simulation, and evaluation of control quality. The controller selection is based on Neimarks D-partition method and Kharitonovs 16 plant theorem. The RobCont extends also other features of the WebPIDDESIGN, i.e. enables to perform the polynomial approximation of the time-delay systems. The paper also contains a case study on a real laboratory process, where common RobCont usage procedure is illustrated. The presented tool is mainly intended for the education purposes in the field of automatic control.

WebPIDDESIGN - software for PID controller design management

The goal of this paper is to present the software tool WebPIDDESIGN for complex management of PID controller design. This tool is suitable for those who need to design the PID controller for the simple closed-loop feedback in an effective and user-friendly way. As the WebPIDDESIGN interface has been currently placed on the Internet, the users may benefit from the simple utilization without the need of complex software and hardware requirements. The features of this tool determine its usability especially for educational purpose. Users of WebPIDDESIGN can reap the benefits of its online form, especially interactivity, information value, ease of use, and accessibility 24/7. This software includes system analysis and identification features, various PID controller design methods, closed loop simulations and evaluation of control quality. As a tool for education, it also provides appropriate theoretical background to specific control design and identification tasks, in such an extent that user is able to understand all performed tasks without an exhaustive effort.

Classification of wine distillates using multivariate statistical methods based on their direct GC-MS analysis

This work describes a novel methodology for the recognition of brandies based on direct injection of a raw sample followed by GC-MS analysis. Direct injection was chosen for its simplicity and the fact that the composition of the samples analysed remains unchanged compared to original brandy. The repeatability of the analytical procedure was evaluated by a comparison of the peak areas for randomly selected compounds obtained from 10 parallel measurements. A novel chemometric procedure was investigated in order to separate the samples studied on the basis of their geographical origin, processing technology or maturation time. In this procedure, a principal component analysis was applied to full chromatograms to select the time interval that shows the significant differences between the samples studied. It was shown that the chromatogram recorded at 36–39 min bore the maximal differences, hence it could be used to classify the brandy samples. The chromatographic peaks found within this time interval were identified and their peak areas determined. These compounds could be used as specific markers for determining geographical origin or processing technology.

Experimental Identification - an Interactive Online Course

Abstract The aim of the article is to present an interactive online course on experimental identification. Besides teaching materials in the traditional workbook form, new computer based training and electronic media – Internet is used to enable interactive and computer supported way of learning.