Krzyszof Oprzędkiewicz

Prof. Krzyszof Oprzędkiewicz

AGH, University of Science and Technology, A. Mickiewicza 30, 30059 Kraków, Poland
orcid

Research Focus & Metrics

Academic Career Length

18Years (2009-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 December 2016 in International Journal of Applied Mathematics and Computer Science
Verified
Journal Article
Open access
Krzyszof OprzędkiewiczKrzyszof Oprzędkiewicz
Krzyszof Oprzędkiewicz
EGEdyta Gawin
Edyta Gawin
WMWojciech Mitkowski
Wojciech Mitkowski
A new, state space, non-integer order model for the heat transfer process is presented. The proposed model is based on a Feller semigroup one, the derivative with respect to time is expressed by the non-integer order Caputo operator, and the derivative with respect to length is described by the non-integer order Riesz operator. Elementary properties of the state operator are proven and a formula for the step response of the system is also given. The proposed model is applied to the modeling of temperature distribution in a one dimensional plant. Results of experiments show that the proposed model is more accurate than the analogical integer order model in the sense of the MSE cost function

24 February 2021 in Electronics
Verified
Journal Article
Open access
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Krzyszof OprzędkiewiczKrzyszof Oprzędkiewicz
Krzyszof Oprzędkiewicz
MRMaciej Rosół
Maciej Rosół
Jakub Żegleń-WłodarczykJakub Żegleń-Włodarczyk
Jakub Żegleń-Włodarczyk
The paper presents time, frequency, and real-time properties of a fractional-order PID controller (FOPID) implemented at a STM 32 platform. The implementation uses CFE approximation and discrete version of a Grünwald–Letnikov operator (FOBD). For these implementations, experimental step responses and Bode frequency responses were measured. Real-time properties of the approximations are also examined and analyzed. Results of tests show that the use of CFE approximation allows to better keep the soft real-time requirements with an accuracy level a bit worse than when using the FOBD. The presented results can be employed in construction-embedded fractional control systems implemented at platforms with limited resources.

1 December 2018 in International Journal of Applied Mathematics and Computer Science
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Journal Article
Open access
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Krzyszof OprzędkiewiczKrzyszof Oprzędkiewicz
Krzyszof Oprzędkiewicz
WMWojciech Mitkowski
Wojciech Mitkowski
A new, state space, discrete-time, and memory-efficient model of a one-dimensional heat transfer process is proposed. The model is derived directly from a time-continuous, state-space semigroup one. Its discrete version is obtained via a continuous fraction expansion method applied to the solution of the state equation. Fundamental properties of the proposed model, such as decomposition, stability, accuracy and convergence, are also discussed. Results of experiments show that the model yields good accuracy in the sense of the mean square error, and its size is significantly smaller than that of the model employing the well-known power series expansion approximation.

26 September 2016
Verified
Conference Paper
Closed access
Krzyszof OprzędkiewiczKrzyszof Oprzędkiewicz
Krzyszof Oprzędkiewicz
WMWojciech Mitkowski
Wojciech Mitkowski
EGEdyta Gawin
Edyta Gawin
In the paper the parameter idetification problem for new, non integer order, state space models of heat transfer process is presented. The solution of all proposed state equations bases directly onto definitions of suitable non integer order differences. The parameters estimation is done with the use of MSE (Mean Square Error) cost function. The order of all proposed state-space models is also estimated. Results of experiments show, that all proposed non integer order models are more accurate in the sense of MSE cost function than known integer order model.

1 June 2016 in Archives of Control Sciences
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Journal Article
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Krzyszof OprzędkiewiczKrzyszof Oprzędkiewicz
Krzyszof Oprzędkiewicz
EGEdyta Gawin
Edyta Gawin
In the paper a new, state space, non integer order model for one dimensional heat transfer process is presented. The model is based on known semigroup model. The derivative with respect to time is described by the non integer order Caputo operator, the spatial derivative is described by integer order operator. The elementary properties of the state operator are proven. The solution of state equation is calculated with the use of Laplace transform. Results of experiments show, that the proposed model is more accurate than analogical integer order model in the sense of square cost function.

5 October 2021 in Energies
Verified
Journal Article
Open access
PDF file
Krzyszof OprzędkiewiczKrzyszof Oprzędkiewicz
Krzyszof Oprzędkiewicz
WMWojciech Mitkowski
Wojciech Mitkowski
MRMaciej Rosół
Maciej Rosół
In this paper, a new, state space, fractional order model of a heat transfer in two dimensional plate is addressed. The proposed model derives directly from a two dimensional heat transfer equation. It employes the Caputo operator to express the fractional order differences along time. The spectrum decomposition and stability of the model are analysed. The formulae of impluse and step responses of the model are proved. Theoretical results are verified using experimental data from thermal camera. Comparison model vs experiment shows that the proposed fractional model is more accurate in the sense of MSE cost function than integer order model.