Examinando por Autor "Miguel Escrig, Oscar"

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    Asymmetric delayed relay feedback identification based on the n-shifting approach
    (Taylor and Francis Group, 2021-08-20) Sánchez Moreno, José; Dormido Bencomo, Sebastián; Miguel Escrig, Oscar; Romero Pérez, Julio Ariel; https://orcid.org/0000-0002-2405-8771; https://orcid.org/0000-0002-2472-2038; https://orcid.org/0000-0003-3397-2239
    The paper presents an improvement of the n-shifting technique to identify the frequency response of an industrial process using a fully asymmetric and delaying relay. The n-shifting approach allows the calculation of n + 1 points of G(s) by an asymmetric relay experiment. This set of n points is composed of G(0), G(jωosc), . . . , G(jnωosc), being ωoscthe oscillation frequency, and where G(jωosc) is in most cases located in the third quadrant of the Nyquist map. By delaying the relay output and repeating a similar experiment it can be generated n additional points of G(s) where the first point is G(jω’ osc) with 0 < ω’osc < ωosc. In this way, it is possible to depict the full output spectrum of G(s) from zero to very high frequencies by a short relay experiment. An example of identification and tuning of a PID controller with data from the n-shifting are presented to show the validity of the approach.
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    Characterization of limit cycle oscillations induced by Fixed Threshold Samplers
    (Institute of Electrical and Electronics Engineers, 2022-06-17) Miguel Escrig, Oscar; Romero Pérez, Julio Ariel; Sánchez Moreno, José; Dormido Bencomo, Sebastián; https://orcid.org/0000-0002-2472-2038; https://orcid.org/0000-0002-2405-8771
    In this work, a generalized study of the conditions for the appearance of limit cycle oscillations induced by any kind of sampler with multilevel fixed thresholds is presented. These kinds of samplers, which will be referred to as Fixed Threshold Samplers (FTS), are characterized by a series of parameters, which, when selected properly, allow obtaining some of the most used forms of quantization in Event-Based Control (EBC). Because of some sampler characteristics, the obtained limit cycle oscillations can present a bias, therefore, to characterize them the Dual Input Describing Function (DIDF) method is used. The obtained DIDF is analyzed revealing some interesting properties allowing to simplify the robustness analysis. The analysis takes into account the effect of the disturbance and reference signal influence on the system, generally overlooked in DF analysis. Guidelines about how to perform the robustness analysis are given, showing their application through some study cases.
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    Error dependent sampling to reduce transient events in event-based control
    (Institute of Electrical and Electronics Engineers, 2025-03-25) Miguel Escrig, Oscar; Romero Pérez, Julio Ariel; Sánchez Moreno, José; Dormido Bencomo, Sebastián
    One of the objectives of event-based control is the reduction of generated events to perform an appropriate process control. Among the event generation techniques used to this end, those quantifying the error signal can be found more frequently for its simplicity of implementation. However, they entail a drawback in the form of trade-off between event generation and performance. Aiming to reduce the number of events, specifically in the transient response, without degrading the performance, an error dependent sampling scheme is studied in this work.
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    A hybrid temporal-magnitude based sampling for Event-Based Control
    (Institute of Electrical and Electronics Engineers, 2025-03-25) Miguel Escrig, Oscar; Sánchez Moreno, José; Romero Pérez, Julio Ariel; Dormido Bencomo, Sebastián
    In the current industrial environment, which is shifting towards an event-based control prone paradigm, sampling strategies in use must be revisited. Both temporal and magnitude dependent sampling strategies have been demonstrated to be suitable for control systems, reporting benefits in different categories. However, these sampling strategies also present some drawbacks, discussed in this contribution. Aiming to address some of these drawbacks, a new sampling strategy is proposed gathering characteristics of both predecessors.
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    Multiple frequency response points identification through single asymmetric relay feedback experiment
    (Elsevier, 2023-01) Miguel Escrig, Oscar; Romero Pérez, Julio Ariel; Dormido Canto, Sebastián; Sánchez Moreno, José; https://orcid.org/0000-0003-3397-2239
    In this paper a methodology to identify several points of the frequency response of a system using a single experiment is proposed. The identification is performed using the information obtained from an asymmetric relay feedback experiment. The frequency response points that are estimated correspond to the fundamental oscillation frequency induced by the asymmetric relay and its harmonics. The method is easy to implement since it only requires linear algebra operations, but relies on a proper data selection, which is largely studied, to obtain the most accurate results. The proposed method allows a Least Squares formulation, which has also been studied, and presents some benefits in terms of accuracy for certain cases. The presented results are validated experimentally using a practical identification case.
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    On-line retuning of PID controllers with fixed threshold samplers
    (Elsevier, 2023-04-11) Miguel Escrig, Oscar; Romero Pérez, Julio Ariel; Dormido Canto, Sebastián; Sánchez Moreno, José
    The appearance of limit cycle oscillations in control systems with fixed threshold based samplers degrades the performance of the control loop, accelerates the wear out of actuators, and introduces an unnecessary communication overhead in distributed control systems. In this paper, the role of the input signals to the control loop is taken into account when analyzing the existence of limit cycles induced by fixed threshold samplers. With this analysis, a methodology to re-tune PID controllers while running to avoid limit cycle oscillations generated by ramp-like excitation signals is presented. Implementation guidelines and several examples to illustrate the usefulness of the method are provided.