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Tong Kun Lim - One of the best experts on this subject based on the ideXlab platform.

Zongli Lin - One of the best experts on this subject based on the ideXlab platform.

  • Output regulation of linear systems with bounded Continuous Feedback
    IEEE Transactions on Automatic Control, 2004
    Co-Authors: Zongli Lin
    Abstract:

    This paper studies the classical problem of output regulation for linear systems subject to control constraint. The asymptotically regulatable region, the set of all initial conditions of the plant and the exosystem for which output regulation is possible, is characterized in terms of the null controllable region of the antistable subsystem of the plant. Continuous output regulation laws, of both state Feedback type and error Feedback type, are constructed from a given stabilizing state Feedback law. It is shown that a stabilizing Feedback law that achieves a larger domain of attraction leads to a Feedback law that achieves output regulation on a larger subset of the asymptotically regulatable region. A Feedback law that achieves global stabilization on the asymptotically null controllable region leads to a Feedback law that achieves output regulation on the entire asymptotically regulatable region.

  • On improving the performance with bounded Continuous Feedback laws
    IEEE Transactions on Automatic Control, 2002
    Co-Authors: Zongli Lin
    Abstract:

    We present controller design methods to smooth the discontinuity resulting from a piecewise linear control law which was proposed to improve the convergence performance for systems with input constraints. The Continuous control laws designed in this paper are explicit functions of the state and are easily implementable. We also show that the convergence performance can be further improved by using a saturated high-gain Feedback law. The efficiency of the proposed methods is illustrated with the PUMA 560 robot model.

  • On improving the performance with bounded Continuous Feedback laws
    Proceedings of the 41st IEEE Conference on Decision and Control 2002., 1
    Co-Authors: Zongli Lin
    Abstract:

    We present controller design methods to smoothen the discontinuity resulting from a piecewise linear control (PLC) law which was proposed to improve the convergence performance for systems with input constraints. The Continuous control laws designed in this paper are explicit functions of the state and are easily implementable. We also show that the convergence performance can be further improved by using a saturated high gain Feedback law. The efficiency of the proposed methods is illustrated with the PUMA 560 robot model.

  • Output regulation with Continuous Feedback for linear systems with saturating actuators
    Proceedings of the 40th IEEE Conference on Decision and Control (Cat. No.01CH37228), 1
    Co-Authors: Zongli Lin
    Abstract:

    We present a controller design method for output regulation for linear systems subject to actuator saturation. The Feedback law is constructed from the stabilizing Feedback law in such a way that a stabilizing Feedback law that achieves a larger domain of attraction leads to a Feedback law that achieves output regulation on a larger subset of the asymptotically regulatable region, and a stabilizing Feedback law on the entire asymptotically null controllable region leads to a Feedback law that achieves asymptotic output regulation on the entire asymptotically regulatable region. In this paper, the control signal is Continuous in time. This complements the result of Hu et al. (2000) where the control signal is disContinuous at the switching surfaces.

Annette Horstmann - One of the best experts on this subject based on the ideXlab platform.

  • intermittent compared to Continuous real time fmri neuroFeedback boosts control over amygdala activation
    NeuroImage, 2018
    Co-Authors: Lydia Hellrung, Anja Dietrich, Maurice Hollmann, Burkhard Pleger, Christian Kalberlah, Elisabeth Roggenhofer, Arno Villringer, Annette Horstmann
    Abstract:

    Real-time fMRI neuroFeedback is a feasible tool to learn the volitional regulation of brain activity. So far, most studies provide Continuous Feedback information that is presented upon every volume acquisition. Although this maximizes the temporal resolution of Feedback information, it may be accompanied by some disadvantages. Participants can be distracted from the regulation task due to (1) the intrinsic delay of the hemodynamic response and associated Feedback and (2) limited cognitive resources available to simultaneously evaluate Feedback information and stay engaged with the task. Here, we systematically investigate differences between groups presented with different variants of Feedback (Continuous vs. intermittent) and a control group receiving no Feedback on their ability to regulate amygdala activity using positive memories and feelings. In contrast to the Feedback groups, no learning effect was observed in the group without any Feedback presentation. The group receiving intermittent Feedback exhibited better amygdala regulation performance when compared with the group receiving Continuous Feedback. Behavioural measurements show that these effects were reflected in differences in task engagement. Overall, we not only demonstrate that the presentation of Feedback is a prerequisite to learn volitional control of amygdala activity but also that intermittent Feedback is superior to Continuous Feedback presentation.

Tilman Esslinger - One of the best experts on this subject based on the ideXlab platform.

  • Continuous Feedback on a quantum gas coupled to an optical cavity
    New Journal of Physics, 2020
    Co-Authors: Katrin Kroeger, Nishant Dogra, Rodrigo Rosa-medina, Marcin Paluch, Francesco Ferri, Tobias Donner, Tilman Esslinger
    Abstract:

    We present an active Feedback scheme acting Continuously on the state of a quantum gas dispersively coupled to a high-finesse optical cavity. The quantum gas is subject to a transverse pump laser field inducing a self-organization phase transition, where the gas acquires a density modulation and photons are scattered into the resonator. Photons leaking from the cavity allow for a real-time and non-destructive readout of the system. We stabilize the mean intra-cavity photon number through a micro-processor controlled Feedback architecture acting on the intensity of the transverse pump field. The Feedback scheme can keep the mean intra-cavity photon number $n_\text{ph}$ constant, in a range between $n_\text{ph}=0.17\pm 0.04$ and $n_\text{ph}=27.6\pm 0.5$, and for up to 4 s. Thus we can engage the stabilization in a regime where the system is very close to criticality as well as deep in the self-organized phase. The presented scheme allows us to approach the self-organization phase transition in a highly controlled manner and is a first step on the path towards the realization of many-body phases driven by tailored Feedback mechanisms.

Keumcheol Kwak - One of the best experts on this subject based on the ideXlab platform.