scholarly journals Stability analysis by dynamic dissipation inequalities: On merging frequency-domain techniques with time-domain conditions

2018 ◽  
Vol 121 ◽  
pp. 7-15 ◽  
Author(s):  
Carsten W. Scherer ◽  
Joost Veenman
Keyword(s):  
Stability Analysis ◽  
Frequency Domain ◽  
Time Domain ◽  
Dissipation Inequalities ◽  
Frequency Domain Techniques

scholarly journals Stability Analysis of Nonlinear Systems with Slope Restricted Nonlinearities

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Xian Liu ◽  
Jiajia Du ◽  
Qing Gao
Keyword(s):  
Stability Analysis ◽  
Nonlinear Systems ◽  
Frequency Domain ◽  
Time Domain ◽  
Absolute Stability ◽  
Lyapunov Method ◽  
Lur’E Systems ◽  
Kyp Lemma

The problem of absolute stability of Lur’e systems with sector and slope restricted nonlinearities is revisited. Novel time-domain and frequency-domain criteria are established by using the Lyapunov method and the well-known Kalman-Yakubovich-Popov (KYP) lemma. The criteria strengthen some existing results. Simulations are given to illustrate the efficiency of the results.

A Numerical Method for Representing Retardation Functions With Complex Exponentials

2017 ◽  
Author(s):  
Fushun Liu ◽  
Lei Jin ◽  
Jiefeng Chen ◽  
Wei Li
Keyword(s):  
Frequency Domain ◽  
Time Domain ◽  
Degrees Of Freedom ◽  
Added Mass ◽  
Memory Effects ◽  
Floating Structure ◽  
Frequency Dependent ◽  
Laplace Domain ◽  
The Time Domain ◽  
Frequency Domain Techniques

Numerical time- or frequency-domain techniques can be used to analyze motion responses of a floating structure in waves. Time-domain simulations of a linear transient or nonlinear system usually involve a convolution terms and are computationally demanding, and frequency-domain models are usually limited to steady-state responses. Recent research efforts have focused on improving model efficiency by approximating and replacing the convolution term in the time domain simulation. Contrary to existed techniques, this paper will utilize and extend a more novel method to the frequency response estimation of floating structures. This approach represents the convolution terms, which are associated with fluid memory effects, with a series of poles and corresponding residues in Laplace domain, based on the estimated frequency-dependent added mass and damping of the structure. The advantage of this approach is that the frequency-dependent motion equations in the time domain can then be transformed into Laplace domain without requiring Laplace-domain expressions of the added mass and damping. Two examples are employed to investigate the approach: The first is an analytical added mass and damping, which satisfies all the properties of convolution terms in time and frequency domains simultaneously. This demonstrates the accuracy of the new form of the retardation functions; secondly, a numerical six degrees of freedom model is employed to study its application to estimate the response of a floating structure. The key conclusions are: (1) the proposed pole-residue form can be used to consider the fluid memory effects; and (2) responses are in good agreement with traditional frequency-domain techniques.

New design methods of actuator saturation compensators for proportional, integral and derivative controllers

1997 ◽  
Vol 211 (4) ◽  
pp. 269-280
Author(s):  
K Hui ◽  
C W Chan
Keyword(s):  
Stability Analysis ◽  
Frequency Domain ◽  
Actuator Saturation ◽  
Variable Structure ◽  
Main Theme ◽  
Relative Stabilities ◽  
Design Procedures ◽  
Proportional Integral ◽  
New Class ◽  
Frequency Domain Techniques

This paper proposes five new schemes of saturation compensator designs for PID (proportional, integral and derivative) controllers. Unlike previous works, these are derived using frequency domain techniques. Based on stability analysis of the compensated systems, comparisons of stabilities of the compensation schemes relative to each other are established, with the result that their relative orders depend only on the PI/PID parameters. A new class of variable-structure compensators is also proposed. These variable-structure compensators combine the advantages of their individual constituents to achieve better results. Design procedures, for both fixed- and variable-structure compensators, are then presented as the main theme of this paper. Results for the relative stabilities and design procedures are illustrated with examples, showing the validity and superiority of the proposed methods.

Reproducibility of Time-domain and Three Different Frequency-domain Techniques for the Analysis of the Signal-Averaged Electrocardiogram

2000 ◽  
Vol 33 (2) ◽  
pp. 99-105 ◽  
Author(s):  
Rafael Vázquez ◽  
Edward B. Caref ◽  
Francisco Torres ◽  
Margarita Reina ◽  
Jose A. Guerrero ◽  
...  
Keyword(s):  
Frequency Domain ◽  
Time Domain ◽  
Frequency Domain Techniques
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