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Hands-on MPC tuning for industrial applications

Ionescu C., Copot D.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2019

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Vol. 67, nr 5

925--945

EN

This paper proposes a practical tuning of closed loops with model based predictive control. The data assumed to be known from the process is the result of the bump test commonly applied in industry and known in engineering as step response data. A simplified context is assumed such that no prior know-how is required from the plant operator. The relevance of this assumption is very realistic in the context of first time users, both for industrial operators and as educational competence of first hand student training. A first order plus dead time is approximated and the controller parameters immediately follow by heuristic rules. Analysis has been performed in simulation on representative dynamics with guidelines for the various types of processes. Three single-input-single-output experimental setups have been used with no expert users available in different locations – both educational and industrial – these setups are representative for practical cases: a variable time delay dominant system, a non-minimum phase system and an open loop unstable system. Furthermore, in a multivariable control context, a train of separation columns has been tested for control in simulation, followed by experimental tests on a laboratory system with similar dynamics, i.e. a sextuple coupled water tank system. The results indicate the proposed methodology is suitable for hands-on tuning of predictive control loops with some limitations on performance and multivariable process control.

2

Fractional order based velocity control system for a nanorobot in non-Newtonian fluids

Muresan C. I., Birs I. R., Folea S., Ionescu C.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2018

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Vol. 66, nr 6

991--997

EN

Customized patient drug delivery overcomes classic medicine setbacks such as side effects, improper drug absorption or slow action. Nanorobots can be successfully used for targeted patient-specific drug administration, but they must be reliable in the entire circulatory system environment. This paper analyzes the possibility of fractional order control applied to the nanomedicine field. The parameters of a fractional order proportional integral controller are determined with the purpose of controlling the velocity of the nanorobot in non-Newtonian fluids envisioning the blood flow in the circulatory system.

3

Mineralogy of the ceramic slags from the Bronze Age funerary site at Lăpuş (NW Romania)

Hoeck V., Ionescu C., Metzner-Nebelsick C., Nebelsick L. D.

Geological Quarterly

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2012

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Vol. 56, No. 4

649–-664

EN

A Bronze Age (13–12 th century B.C.) necropolis and cult area in Lăpuş (NW Romania) has been studied. The mound investigated during the present campaign covered a multi-phased wooden cult building containing bronze objects, ceramic potshards and slag pieces. The latter have a mammillary smooth surface, irregular shape and a high porosity. Optical microscopy reveals a colourless to brown vitreous mass, full with various-sized pores making up to 40 vol.% of the total slag. The glass includes relic phases, e.g., quartz, partly melted plagioclase and rutile, rare zircon, ilmenite and magnetite-rich spinel. Cristobalite and various silicates were formed within the glass and at the wall of the vesicles during cooling. The latter include fayalite, ferrosilite, magnetite-dominated spinel, hematite, clinopyroxene, mullite and cordierite. About 1/3 of the total volume of the slag consists of glass with a wide variety of SiO2 ranging from 49 to 76 wt.%. It is inhomogeneous, with local enrichment in Fe, Ca, Mg, Ti and K. The pore structure, the partial melting of plagioclase and rutile, the newly formed SiO2 polymorphs (cristobalite) and the Fe(Al) silicates indicate, all indicate maximum temperatures of 1100–1200°C for the fire generating the slags. The slags are not related to any metallurgical but to an anthropogenic pyrometamorphic process and formed as a result of overfiring some ceramic vessels which may have contained ritual offerings. Intentionally initiated firing of the wooden structures is the most likely the agent of this high temperature. The slags resemble buchites and can be termed “ceramic slags”

4

Early Eocene age of a sandstone from the Buntmergel Formation (Gresten Klippen Zone, Lower Austria)

Gasiński M. A., Hoeck V., Ślączka A., Ionescu C.

Geological Quarterly

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2012

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Vol. 56, No. 4

845--852

EN

The Gresten Klippen Zone is an individual geological unit, mainly outcropping at the northern rim of the Northern Calcareous Alps. It is best exposed between the Enns Valley in the west and the Vienna Forest in the east. It contains a rock sequence ranging from Early Jurassic to Early Cretaceous, including sandstones, various limestones, breccias and radiolarites. The late Early Cretaceous–Paleogene is represented by the Buntmergel Formation. A sandstone block from the latter yields well-preserved planktonic foraminiferids which allow an assignment to the Early Eocene (E-7 Zone). The low density currents which deposited the parallel laminated sandstones originated in the lower shelf-middle slope.

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Some challenging feedback-control applications in biomedical systems

Ionescu C., Keyser R. de

Journal of Medical Informatics & Technologies

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2005

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Vol. 9

35--46

EN

Natural biological control involves the normal functioning of the living organism (i.e. human body) to regulate its parameters such that the vital functions are kept within the normal operating range. When this natural control fails, the biological feedback (thus a closed loop system) is unstable and/or operates under non-optimal conditions of the vital capacity of the subject. In this context, ensuring surviving capacity of the subject implies to artificially control the vital functions presenting the functional failure. Nowadays technology enables development of artificial closed loop devices to correct and provide the normal functions of the organism, replacing thus the damaged/non-optimal parts or helping in recovering their natural properties (rehabilitation techniques). Two of the most en-vogue applications of artificial control will exemplify the importance and the posed challenges: - a neuroprothesis device to control paralyzed skeletal muscles; this enables rehabilitation of drop-foot or hand-grasp movements with paretic or paralyzed skeletal muscles by use of a self-adaptive (auto-tuning) control strategy; - and an artificial pancreas for diabetes type I patients; the blood glucose control in diabetic patients type I is made by use of an in-house developed model-based predictive control algorithm in which input (insulin rate) and output (glucose level) are constrained.