138 research outputs found
Conditions for the equivalence between IQC and graph separation stability results
This paper provides a link between time-domain and frequency-domain stability
results in the literature. Specifically, we focus on the comparison between
stability results for a feedback interconnection of two nonlinear systems
stated in terms of frequency-domain conditions. While the Integral Quadratic
Constrain (IQC) theorem can cope with them via a homotopy argument for the
Lurye problem, graph separation results require the transformation of the
frequency-domain conditions into truncated time-domain conditions. To date,
much of the literature focuses on "hard" factorizations of the multiplier,
considering only one of the two frequency-domain conditions. Here it is shown
that a symmetric, "doubly-hard" factorization is required to convert both
frequency-domain conditions into truncated time-domain conditions. By using the
appropriate factorization, a novel comparison between the results obtained by
IQC and separation theories is then provided. As a result, we identify under
what conditions the IQC theorem may provide some advantage
Phase limitations of Zames-Falb multipliers
Phase limitations of both continuous-time and discrete-time Zames-Falb
multipliers and their relation with the Kalman conjecture are analysed. A phase
limitation for continuous-time multipliers given by Megretski is generalised
and its applicability is clarified; its relation to the Kalman conjecture is
illustrated with a classical example from the literature. It is demonstrated
that there exist fourth-order plants where the existence of a suitable
Zames-Falb multiplier can be discarded and for which simulations show unstable
behavior. A novel phase-limitation for discrete-time Zames-Falb multipliers is
developed. Its application is demonstrated with a second-order counterexample
to the Kalman conjecture. Finally, the discrete-time limitation is used to show
that there can be no direct counterpart of the off-axis circle criterion in the
discrete-time domain
Intramolecular [3+2] Cycloaddition of Fused Azolo-Azepanes from Azido Monosaccharides Derivatives
Síntesis de bicíclicos compuestos empleando epoxiamidas como material de partida. Obtención de tetrazolo azepanos con posible actividad biológica.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Sim-to-Real Deep Reinforcement Learning with Manipulators for Pick-and-place
When transferring a Deep Reinforcement Learning model from simulation to the
real world, the performance could be unsatisfactory since the simulation cannot
imitate the real world well in many circumstances. This results in a long
period of fine-tuning in the real world. This paper proposes a self-supervised
vision-based DRL method that allows robots to pick and place objects
effectively and efficiently when directly transferring a training model from
simulation to the real world. A height-sensitive action policy is specially
designed for the proposed method to deal with crowded and stacked objects in
challenging environments. The training model with the proposed approach can be
applied directly to a real suction task without any fine-tuning from the real
world while maintaining a high suction success rate. It is also validated that
our model can be deployed to suction novel objects in a real experiment with a
suction success rate of 90\% without any real-world fine-tuning. The
experimental video is available at: https://youtu.be/jSTC-EGsoFA
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