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1

Digital approach to thermionic emission current to voltage conversion for high-voltage sources of electrons

Kania Bartosz

Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska

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2022

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T. 12, nr 4

78--81

EN

The thermionic emission current is used in many vacuum devices such as evaporators, rare gas excimers, or electron beam objects for highenergy physics. The stability of the thermionic emission current is a very important requirement for the accuracy of those devices. Hence, there is a number of control systems that use a feedback signal directly proportional to the emission current in order to stabilize the thermionic emission current. Most of them use feedback from a high-voltage anode circuit to a low-voltage cathode circuit. However, there is a novel solution that uses linear cathode current distribution and processing of two cathode circuit voltage signals for converting the emission current to voltage. However, it is based on old-fashioned analog technology. This paper shows the thermionic emission current to voltage conversion method with the use of a digital control system. A digital realization of a multiplicative-additive algorithm is presented and proper work in closed-loop mode is confirmed.

PL

Prąd termoemisji elektronowej jest wykorzystywany w wielu przyrządach próżniowych takich jak ewaporatory, ekscymery gazów rzadkich czy w fizyce wysokich energii. Stabilność natężenia prądu termoemisji elektronowej jest ważnym wymaganiem w kontekście dokładności tych przyrządów. Istnieje wiele układów regulacji natężenia prądu termoemisji elektronowej, które używają sygnału sprzężenia zwrotnego wprost proporcjonalnego do natężenia prądu termoemisji elektronowej w celu jego stabilizacji. Większość z nich wykorzystuje sprzężenie od wysokonapięciowego obwodu anody do niskonapięciowego obwodu katody. Istnieje nowe rozwiązanie, które wykorzystuje liniowy rozkład prądu katody oraz przetwarzanie dwóch sygnałów z obwodu katody w celu konwersji natężenia prądu termoemisji na napięcie. Niestety metoda ta bazuje na przestarzałej technologii analogowej. W niniejszej pracy pokazana została konwersja natężenia prądu termoemisji elektronowej na napięcie z użyciem cyfrowego układu automatycznej regulacji. Cyfrowa realizacja algorytmu multiplikatywno-addytywnego została zaprezentowana, a poprawna praca w zamkniętej pętli sprzężenia zwrotnego potwierdzona.

2

Badania porównawcze liniowych regulatorów dla lewitacji magnetycznej

Jasik D., Wajnert D.

Pomiary Automatyka Robotyka

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2018

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R. 22, nr 3

51--59

PL

W artykule przedstawiono sposób implementacji algorytmów regulacji do sterowania lewitacją magnetyczną wykorzystując system szybkiego prototypowania bazujący na karcie dSPACE DS1104 wraz z oprogramowaniem MATLAB/Simulink. Praca przedstawia możliwości uzyskania zjawiska lewitacji magnetycznej oraz opisuje obiekt, na którym były prowadzone badania. Rozpatrywany obiekt przedstawiono za pomocą modelu matematycznego, na podstawie którego zbudowano model symulacyjny w programie MATLAB. Kolejno określono rozpatrywane wskaźniki jakości regulacji oraz zdefiniowano trzy układy podlegające badaniu: PI-PID, LQR, LQI. Na zakończenie porównano wskaźniki jakości regulacji dla każdego układu.

EN

This work presents the implementation of the control algorithms for the magnetic levitation with using a rapid prototype system based on dSPACE DS1104 card and MATLAB/Simulink software. The work presents the possibility of obtaining the phenomenon of magnetic levitation and description of the object on which the research was conducted. The mathematical model of the object was formulated, its parameters were determined, and the simulation model was developed in MATLAB/Simulink. After introducing control system performance indices, three different regulators were defined: PI-PID, LQR and LQI. Finally, the results of implemented control algorithms for different settings has been shown. Control system performance indices of all three regulators were compared.

3

Unscented and extended Kalman filters study for sensorless control of PM synchronous motors with load torque estimation

Zawirski K., Janiszewski D., Muszynski R.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2013

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Vol. 61, nr 4

793--801

EN

This paper describes a study and the experimental verification of sensorless control of permanent magnet synchronous motors using Kalman filters. There are proposed two structures, extended and unscented Kalman filters, which use only the measurement of the motor current for on-line estimation of speed, rotor position and load torque reconstruction. The Kalman filter is an optimal state estimator and is usually applied to a dynamic system that involves a random noise environment. These structures are described in detail, starting with the selection of the variables state vector, the filters structure, and ending with in-depth laboratory tests. It has become possible, without using position and torque sensors, to apply these control structures as a cost-effective solution. Experimental results confirm the validity of the proposed estimation techniques.

4

Synthesis of time-optimal control for a class of linear systems

Penev B. G., Christov N. D.

Systems Science

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2006

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Vol. 32, no 1

15-26

EN

The paper deals with the optimal control synthesis for a class of linear time-optimal control problems of decreasing order. The state-space properties and relationships between two neighbouring problems within this class are studied. Based on these properties, a new approach is proposed for synthesis of time-optimal control, requiring no description of the switching hyper-surface. The approach consists of two main stages: first, the problems of state spaces are analysed, and then the optimal control is obtained by using a multi-stage procedure within the class of problems under consideration.

5

LQR and predictive control tuned via BDU

Ramos C., Sanchis J., Martinez M., Herrero J. M.

Systems Science

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2005

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Vol. 31, no 1

15-25

EN

This work presents the BDU technique (Bounded Data Uncertainties) and the tuning of the linear quadratic regulator (LQR) via this technique, which considers models with bounded uncertainties. The BDU method is based on constrained game-type formulations, and allows the designer to explicitly incorporate a priori information about bounds on the sizes of the uncertainties into the problem statement. Thus, on the one hand, the uncertainty effect is not over-emphasized, avoiding an overly conservative design and, on the other hand, the uncertainty effect is not under-emphasized, avoiding an overly sensitive to errors design. A feature of this technique consists of its geometric interpretation. The structure of the paper is the following, in the first section, some problems about the least-squares method in the presence of uncertainty are introduced. The BDU technique is shown in the second section and the LQR controller in the third. After that a new guided way of tuning the LQR is offered, taking into account the uncertainties bounds via the BDU. The consequence of this method is that both recursive and algebraic Riccati equations are modified. Finally, some examples are shown and the main conclusions and future work are commented.

6

A comparison of control systems for ship roll stabilisation

Law Y., Koshkouei A. J., Burnham K. J.

Systems Science

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2005

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Vol. 31, no 2

77-87

EN

This paper presents the results of a fin-rudder controller synthesis for roll reduction where different types of controllers are tested and compared. Three different main types of controllers including PID, advance phase, dual loop transfer recovery (LTR) and sliding mode (SMC) controllers are considered to stabilise the ship motion. The system comprises three different controllers, fin and rudder controllers, and autopilot. Therefore, for each situation of the ship journey, the triple controllers should be designed. It is not necessary to have the same controller structure for all three submodels. This paper compares these various controllers individually for each submodel, and demonstrates the results of the implementation of controllers with different structures when applied to the entire system.

7

Modular control of large distributed discrete event systems

Komenda J.

Systems Science

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2004

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Vol. 30, no 1

51-63

EN

Coalgebra and coinduction provide new results and insights for modular supervisory control of discrete-event systems (DES), where the overall system is composed of subsystems that are combined in synchronous (parallel) product. Modular supervisory control is studied within the coalgebraic framework. Coinduction has been used to define an operation on languages called supervised product, and synchronous product is defined by coinduction. We have shown recently that the supremal controllable sublanguage of a given language can be defined by coinduction as well. We study the commutativity between the synchronous product and supremal controllable and normal sublanguage. The results guarantee that under the conditions derived in the paper control synthesis can be done locally without affecting the optimality of the solution.

8

GPC in state space with robust observer: constraint satisfaction based on invariant sets

Salcedo J. V., Martinez M., Sanchis J., Blasco F. X.

Systems Science

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2004

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Vol. 30, no 1

77-90

EN

The Generalized Predictive Controller (GPC) [1], [2] belongs to the general class of predictive controllers. The authors have proposed an alternative (although equivalent) formulation for the GPC in state space [7]. This formulation is based on a robust observer [5], and the poles selection is closely related to the controller robustness. An important feature of predictive controllers consists of their ability to take explicitly into account hard constraints in their formulation. However, their design must be accompanied by a guarantee of feasibility. There are some papers which deal with (his problem [4], [9], [8], [3], although all of them suppose that the state of the process can be measured on-line. However, in some cases, the design of the GPC proposed by the authors cannot measure online the process states since they are artificial states, that is to say, not related to physical magnitudes. The authors in paper [6] extend the results of [3] to the GPC in the case where all the states are online measurable. So the state estimation will be presented employing the same ideas of this previous work [6]. When the states have to be observed with the robust observer proposed, the authors show that there appears in the analysis a linear but time varying system perturbed with the error in the initial estimation of states. This initial error belongs to a known and bounded set. The main result states that if it is possible to find a collection of non-empty sets K_j that converge to the maximal robust control invariant set when j increases, the feasibility of GPC control law is guaranteed for all the sampling instants. Finally, this result is verified in a numerical example with a 2 states process.

9

Brief review of tasks and results of programm of creation of unified geometrical theory of control (UGTC)

Butkovskiy A. G., Babichev A. V.

Systems Science

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2004

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Vol. 30, no 1

37-42

EN

The purpose of this paper is in very much compressed thesis form to depict the results and problems that were obtained during development of "Unified geometrical theory of control (UGTC)", or "Theory of control structures (TCS)". It is emphasized that UGTC deals with control of structures and symmetries, and a number of structures are considered. Because the UGTC treats the basic concepts of control theory, some main philosophical and methodological principles related to the control science and mathematics are discussed. Concrete theoretical results are given in geometrical form, which permits to show the invariance and generality of these statements. Particularly, the geometrical construction of foliation extends to the synthesis in the control theory as well as to the choice axiom in the set theory, demonstrating an important connection between appropriate problems. Also the problems of axiomatic control theory and control in metric and topological spaces are mentioned. For systems with differential structure the various representations in terms of differential forms, partial differential equations and phase portraits of differential inclusions are considered. The relation between optimality principle and physical variable of energy tensor is determined.

10

Robust variable structure model following controller for load frequency control

Patre B.M., Bandyopadhyay B., Unbehauen H.

Systems Science

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2002

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Vol. 28, nr 4

43-59

EN

A systematic procedure for design of variable structure model following load frequency controller for a single-area power system has been presented. The variable structure model following control (VSMFC) technique presented in this paper not only guarantees invariance to a class of parameter variations and disturbances but also possesses other attractive features of variable structure systems (VSS) such as robustness to unknown disturbances, simplicity in design, and reduced order dynamics when in sliding mode. The simulation results of the variable structure model following control strategy to load frequency control are presented by changing all parameters by 30% to 50% from their nominal values. These results show that systems performance is robust to parameter variations and disturbances.

11

Multi-loop linear control systems design

Goncharov V., Barkovsky A., Blinova N., Datsko O.

Systems Science

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2002

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Vol. 28, nr 4

5-16

EN

A numerical synthesis method of continuous control systems having few internal loops is proposed. Every loop may contain the correcting devices both in the direct channel and in the feedback circuit. The basis of the method is a real integral transform allowing writing the synthesis equation in the image domain in such a way that it contains the functions of real argument only. The interpolation approach provides the development of synthesis equations for the unknown coefficients of correcting device transfer functions. The system solution by Newton's method is found.

12

Discrete time sliding mode control - an advanced reaching law approach

Bartoszewicz A.

Systems Science

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2002

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Vol. 28, nr 4

35-42

EN

In this paper, an advanced discrete-time reaching law is proposed and applied to the design of a sliding mode controller. The controller reduces the influence of a sinusoidal disturbance and parameter uncertainty on the system dynamics to an arbitrarily small level. Furthermore, the controller guarantees existence of the ideal sliding mode in the discrete-time system provided that the total influence of disturbance and parameter uncertainty on the system dynamics is represented by a polynomial function of time. The sliding mode is reached in a finite time. The strategy proposed in this paper can be applied to linear time-varying systems subject to disturbance and modelling uncertainty