Browsing by Author "Verly, Anny"

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    A circuit for automatic measurement of bifurcation diagram in nonlinear electronic oscillators.
    (2016) Ricco, Rodrigo Augusto; Verly, Anny; Amaral, Gleison Fransoares Vasconcelos
    Experimental bifurcation diagram is very helpful to describe the global behaviour of nonlinear electronic oscillators. The diagram allows insight gain of the oscillators behaviour for a parameter variation. However, when the bifurcation parameter is a resistance, experimental bifurcation diagrams are hard to achieve. In this case, if the potentiometer resistance has been used to change the gain, it is possible to replace the potentiometer by an alternative circuit using operational transconductance amplifier. This kind of circuit is presented in this work and experimental results are provided to piecewise affine Rössler electronic oscillator. The results obtained show a very good matching with the theoretical diagram. Then, if the bifurcation parameter is a resistance, voltage or current, we have implemented a circuit to extract the experimental bifurcation diagram of all nonlinear electronic oscillators.
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    Subspace identification of linear systems with partial eigenvalue constraints.
    (2019) Ricco, Rodrigo Augusto; Verly, Anny; Paula, Marcus Vinicius de; Teixeira, Bruno Otávio Soares
    For subspace identification methods with eigenvalue constraints, the constraints are enforced by means of an optimization problem subject to LMI constraints. First principals or step response tests could be used as a source of auxiliary information in order to build LMI regions. In these cases, all the eigenvalues of the identified state-space model are subject to the same constraints. However, it often happens that the non-dominant eigenvalues have larger real part or larger natural frequencies. In this paper, we propose a two-step method in order to constrain the dominant dynamics of SISO models into LMI regions. In virtue of this result, in addition, the model eigenvalues could be constrained into disjoint LMI regions. Numerical examples illustrate the effectiveness of our proposed method.