Wyniki wyszukiwania - BazTech

1

Novel solutions on model-based and model-free robotic-assisted ankle rehabilitation

Arceo Juan Carlos, Alvarez Jorge, Armenta Carlos, Lauber Jimmy, Cremoux Sylvian, Simoneau-Buessinger Emilie, Bernal Miguel

Archives of Control Sciences

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2021

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Vol. 31, No. 1

5--27

EN

In this report, ankle rehabilitation routines currently approved by physicians are implemented via novel control algorithms on a recently appeared robotic device known as the motoBOTTE. The physician specifications for gait cycles are translated into robotic trajectories whose tracking is performed twofold depending on the availability of a model: (1) if obtained via the Euler-Lagrange approach along with identification of unknown plant parameters, a new computed-torque control law is proposed; it takes into account the parallel-robot characteristics; (2) if not available, a variation of the active disturbance rejection control technique whose parameters need to be tuned, is employed. A detailed discussion on the advantages and disadvantages of the model-based and model-free results, from the continuous-time simulation to the discrete-time implementation, is included.

2

Zastosowanie równań różniczkowo-algebraicznych do predykcji zmian parametrów powietrza wewnętrznego

Kwiatkowska M., Szczurek A., Drąg P.

Przegląd Elektrotechniczny

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2016

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R. 92, nr 5

181--184

PL

W pracy podjęto próbę zastosowania układów równań różniczkowo-algebraicznych DAEs niestosowanych dotychczas do predykcji zmian parametrów określających jakość powietrza wewnętrznego. Za wskaźniki charakteryzujące jakość powietrza w pomieszczeniach zamkniętych uważa się temperaturę, stężenie ditlenku węgla oraz wilgotność względną. W celu zamodelowania przyszłych zmian wskazanych parametrów zaproponowano układ równań różniczkowo-algebraicznych. W stosowanym podejściu zastosowano metodę ruchomego okna czasowego o zróżnicowanej długości. Długość okna wynosiła odpowiednio: 4, 8 oraz 10 punktów czasowych. Horyzont predykcji zawierał się w granicach: 1-15 minut. Do oceny jakości predykcji zastosowano trzy wielkości: średni błąd absolutny, maksymalny błąd absolutny oraz pierwiastek ze średniego błędu kwadratowego.

XX

In this paper we attempt to apply differential-algebraic systems to predict changes of indoor air quality (IAQ). So far, differential-algebraic equations (DAEs) have not been used in this way. The indicators of the indoor air quality, which were examined are temperature, relative humidity and carbon dioxide concentration. In order to model changes of these parameters the system of differential-algebraic equations was proposed. The approach applied in this work utilized the method of moving time window with variable length (4, 8, 10 time points). In these time windows models were parameterized. The prediction horizon was in the range from 1 to 15 minutes. To assess prediction quality three measures were used: mean absolute error, maximum absolute error and root mean squared error.

3

The inexact Newton backtracking method as a tool for solving differential-algebraic systems

Drąg P., Styczeń K.

Czasopismo Techniczne. Automatyka

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2013

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R. 110, z. 4-AC

53--64

EN

The classical inexact Newton method was presented as a tool for solving nonlinear differential-algebraic equations (DAEs) in a fully implicit form F(y, y, t) = 0. This is especially in chemical engineering where describing the DAE system in a different form can be difficult or even impossible to realize. The appropriate rewriting of the DAEs using the backward Euler method makes it possible to present the differentialalgebraic system as a large-scale system of nonlinear equations. To solve the obtained system of nonlinear equations, the inexact Newton backtracking method was proposed. Because the convergence of the inexact Newton algorithm is strongly affected by the choice of the forcing terms, new variants of the inexact Newton method were presented and tested on the catalyst mixing problem.

PL

Klasyczna niedokładna metoda Newtona została przedstawiona jako narzędzie do rozwiązywania równań różniczkowo-algebraicznych zapisanych w formie niejawnej F(y, y, t) = 0 . Zapisanie układu równań różniczkowo-algebraicznych w innej postaci w różnych zastosowaniach może być trudne lub niewskazane. Odpowiednie przekształcenie układów różniczkowo-algebraicznych z wykorzystaniem wstecznej metody Eulera umożliwia przedstawienie układu równań różniczkowo-algebraicznych jako układu równań nieliniowych dużej skali. W celu rozwiązania otrzymanego układu równań zaproponowano niedokładną metodę Newtona z nawrotami. Na zbieżność niedokładnej metody Newtona znacząco wpływa wybór czynnika wymuszającego. Nowe warianty niedokładnej metody Newtona zostały zastosowane do rozwiązania układu opisującego proces mieszania w obecności katalizatora.

4

Reducing the dynamics of a space robot modeled with quaternions

Isenberg D. R., Kakad Y. P.

Systems Science

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2009

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Vol. 35, no 2

49-57

EN

This paper begins by describing the dynamical modeling of a two-link space manipulator using a constrained Lagrangian approach to mechanics. The dynamics of the space robot are obtained as a system of index-3 differential algebraic equations due to the use of quaternions as rotation operators. These equations are converted into a system of ordinary differential equations. A computed torque technique is utilized, based on the ordinary differential equation model, to reduce the size of the dynamical equations. The limitations of the technique are discussed. Specifically, it is shown that the input forces cannot be completely decoupled. As an example of how the composite system might be used, a proportional-derivative controller is implemented. The current limitations in analysis for this type of system are also described.

5

A novel interval arithmetic approach for solving differential-algebraic equations with VALENCIA-IVP

Rauh A., Brill M., Günther C.

International Journal of Applied Mathematics and Computer Science

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2009

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Vol. 19, no 3

381-397

EN

The theoretical background and the implementation of a new interval arithmetic approach for solving sets of differential-algebraic equations (DAEs) are presented. The proposed approach computes guaranteed enclosures of all reachable states of dynamical systems described by sets of DAEs with uncertainties in both initial conditions and system parameters. The algorithm is based on VALENCIA-IVP, which has been developed recently for the computation of verified enclosures of the solution sets of initial value problems for ordinary differential equations. For the application to DAEs, VALENCIA-IVP has been extended by an interval Newton technique to solve nonlinear algebraic equations in a guaranteed way. In addition to verified simulation of initial value problems for DAE systems, the developed approach is applicable to the verified solution of the so-called inverse control problems. In this case, guaranteed enclosures for valid input signals of dynamical systems are determined such that their corresponding outputs are consistent with prescribed time-dependent functions. Simulation results demonstrating the potential of VALENCIA-IVP for solving DAEs in technical applications conclude this paper. The selected application scenarios point out relations to other existing verified simulation techniques for dynamical systems as well as directions for future research.

6

Discrete model of a rope with scleronomic and rheonomic constraints

Fritzkowski P., Kamiński H.

Vibrations in Physical Systems

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2008

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Vol. 23

121--126

EN

A preliminary discrete model of a rope with scleronomic and rheonomic constraints is considered. Numerical experiments are performed and advantages of the applied algorithm are discussed in terms of total energy of the system. In case of the nonconservative model the work-energy relation is used to assess the computation efficiency. The next directions of the model development are outlined.

7

Discrete model of a rope with members of a changeable length

Fritzkowski P., Kamiński H.

Vibrations in Physical Systems

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2008

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Vol. 23

127--132

EN

A discrete model of a rope with elements of a changeable length is considered. Scleronomic and rheonomic constraints are given to the system. Dynamic equations of motion are formulated and their complexity is presented from the computational point of view. Numerical experiments are performed and the obtained results are discussed in terms of the total energy of the system.

8

A Boundary-Value Problem for Linear Pdaes

Marszałek W., Trzaska Z.

International Journal of Applied Mathematics and Computer Science

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2002

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Vol. 12, no 4

487-491

EN

We analyze a boundary-value problem for linear partial differential algebraic equations, or PDAEs, by using the method of the separation of variables. The analysis is based on the Kronecker-Weierstrass form of the matrix pencil [A,-ln B]. A new theorem is proved and two illustrative examples are given.