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1

Inverse and forward surrogate models for expedited design optimization of unequal-power-split patch couplers

Koziel Slawomir, Bekasiewicz Adrian

Metrology and Measurement Systems

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2019

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Vol. 26, nr 3

463--473

EN

In the paper, a procedure for precise and expedited design optimization of unequal power split patch couplers is proposed. Our methodology aims at identifying the coupler dimensions that correspond to the circuit operating at the requested frequency and featuring a required power split. At the same time, the design process is supposed to be computationally efficient. The proposed methodology involves two types of auxiliary models (surrogates): an inverse one, constructed from a set of reference designs optimized for particular power split values, and a forward one which represents the circuit S-parameter gradients as a function of the power split ratio. The inverse model directly yields the values of geometry parameters of the coupler for any required power split, whereas the forward model is used for a post-scaling correction of the circuit characteristics. For the sake of illustration, a 10-GHz circular sector patch coupler is considered. The power split ratio of the structure is re-designed within a wide range of -6 dB to 0 dB. As demonstrated, precise scaling (with the power split error smaller than 0.02 dB and the operating frequency error not exceeding 0.05 GHz) can be achieved at the cost of less than three full-wave EM simulations of the coupler. Numerical results are validated experimentally.

2

Control scheme without force sensors for load sensing in telemanipulation systems with force-feedback

Saków M., Marchelek K., Parus A., Miądlicki K.

Journal of Machine Construction and Maintenance - Problemy Eksploatacji

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2017

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no. 3

21--30

EN

The paper presents a novel approach to the control design of bilateral teleoperation systems with force-feedback dedicated only for weight sensing. The problem statement, analysis of related papers up to date, and the scope of the study are presented. The new design of a control unit for a master-slave system with force-feedback was based on an inverse model. The model was applied to subtract a value of force in the force-feedback communication channel that the system might generate during free-motion. A substantial part of the paper is focused on the development of a mathematical model for the investigated control scheme. The paper presents the modelling procedure of the experimental setup and the model used in the study. Two experiments are described to demonstrate the control unit of the master-slave system with force-feedback. The paper contains conclusions regarding to the control and the experimental setup.

PL

W artykule przedstawiono nowe podejście do projektowania sterowania dwustronnych systemów obustronnego działania ze sprzężeniem siłowym zwrotnym, przeznaczonym wyłącznie do wykrywania obciążenia. W artykule został zaprezentowany opis problemu, analiza dotychczasowych osiągnięć badawczych oraz zakres badania. Nowy projekt jednostki sterującej dla systemu Master-Slave ze sprzężeniem siłowym zwrotnym oparty został na modelu odwrotnym. Model został użyty do odejmowania wartości siły w kanale komunikacyjnym sprzężenia zwrotnego, który jest generowany przez system podczas ruchu swobodnego. Znaczna część pracy koncentruje się na opracowaniu modelu matematycznego obejmującego zjawiska występujące w badanym schemacie kontroli. W pracy przedstawiono wnioski dotyczące systemu kontroli oraz omówiono procedurę modelowania konfiguracji eksperymentalnej oraz model zastosowany w układzie sterowania. Opisane są dwa eksperymenty, aby zademonstrować jednostkę sterującą systemu master-slave ze sprzężeniem siłowym zwrotnym. W pracy przedstawiono również wnioski dotyczące wyników eksperymentalnych.

3

Remarks on an inverse modelling of welding processes

Ranatowski E.

Advances in Materials Science

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2005

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Vol. 5, nr 1-3

21-31

EN

At the beginning of this work a short characteristic of the methodology of modelling rules of welding process is provided. The relation between both the intensive and extensive parameters are mainly discussed. Additionally, the theoretical bases of modelling of welding processes are presented. In further on the bases of modelling of inverse heat conduction problem is talked over. It bases on the strategy of solving inverse problems [2], it employs the hybrid an analytic - numerical method for analysis these questions. Finally, the appropriate algorithms in moving and stationary systems are established which can be directly applied to solving inverse problem.

4

A control algorithm applied to polarization states of light in the nonlinear optical resonator

Wierzbicki M.

Control and Cybernetics

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2002

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Vol. 31, no 1

129-139

EN

In this paper a control algorithm is presented for a nonlinear system defined by a nonlinear mapping F : R^n -> R^n of input states to output states of the system, for the problem of motion in the R^n space of output states along the given trajectory. The application of this algorithm in nonlinear optics is presented, for the control of light polarization transmitted through the Fabry-Perot resonator filled with a material with nonlinear optical properties. The calculated trajectory in the space of polarization states of output light leads to the phenomenon of optical bistability, i.e. sudden changes of output polarization induced by small variations of the input parameters, and the dependence of the current state of light polarization on the history of the system.

5

Example - Based Inverse Diagnostic Models

Cholewa W.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2001

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vol. 49, nr 2

359-377

EN

Diagnostic model of an object describes the relations between observed symptoms and their causes, i.e. the technical states of the object. Direct specification of such models is (quite) impossible due to the complex nature of these relations. This paper aims to inform the reader about the general idea of inverse diagnostic models. A special attention has been drawn to the application of known cause-effect dynamic models of investigated objects. Such models transform features of technical states into diagnostic symptoms. Their numerical inversion makes it possible to identify the global as well as local diagnostic models, with the latter ones being more appropriate. Local models have interesting features, but they require experienced users and sophisticated computing techniques. General methods for their identification are still being developed. An interesting idea is connected with the possibility of considering such local models as example based models, i.e. models spanned on particular sets of pattern data.