Inverse parameter-dependent Preisach operator in thermo-piezoelectricity modeling

Abstract Gain-parameter-dependent transfer functions and phase-noise performances in a mode-locked Yb-doped fiber laser are measured in this study. It is discovered that the corner frequency in the amplitude and phase domains is determined by the absorption coefficient of the gain fiber, when the total absorption and other cavity parameters are fixed. This shows that an oscillator using gain fiber with higher dopant concentration accumulates more phase noise. Furthermore, we present net cavity dispersion-dependent transfer functions to verify the effect of dispersion management on the frequency response. We derive a guideline for optimizing mode-locked fiber laser design to achieve low phase noise and timing jitter.

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Parameter-dependent actuator fault estimation for vehicle active suspension systems based on RBFNN

Proceedings of the Institution of Mechanical Engineers Part D Journal of Automobile Engineering ◽

10.1177/0954407021993014 ◽

2021 ◽

pp. 095440702199301

Author(s):

Wenping Xue ◽

Pan Jin ◽

Kangji Li

Keyword(s):

Fault Tolerant ◽

External Disturbance ◽

Active Suspension ◽

Fault Estimation ◽

Linear Matrix ◽

Actuator Fault ◽

Mass Variation ◽

Fe Method ◽

Comparison Results ◽

Parameter Dependent

The actuator fault estimation (FE) problem is addressed in this study for the quarter-car active suspension system (ASS) with consideration of the sprung mass variation. Firstly, the ASS is modeled as a parameter-dependent system with actuator fault and external disturbance input. Then, a parameter-dependent FE observer is designed by using the radial basis function neural network (RBFNN) to approximate the actuator fault. In addition, the design conditions are turned into a linear matrix inequality (LMI) problem which can be easily solved with the aid of LMI toolbox. Finally, simulation and comparison results are given to show the accuracy and rapidity of the proposed FE method, as well as good adaptability against the sprung mass variation. Moreover, a simple FE-based active fault-tolerant control (AFTC) strategy is provided to further demonstrate the effectiveness and applicability of the proposed FE method.

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Quantifying the parameter dependent basin of the unsafe regime of asymmetric Lévy-noise-induced critical transitions

Applied Mathematics and Mechanics ◽

10.1007/s10483-021-2672-8 ◽

2020 ◽

Vol 42 (1) ◽

pp. 65-84

Author(s):

Jinzhong Ma ◽

Yong Xu ◽

Yongge Li ◽

Ruilan Tian ◽

Shaojuan Ma ◽

...

Keyword(s):

Lévy Noise ◽

Stable Model ◽

Efficient Tool ◽

Escape Probability ◽

Critical Transitions ◽

Current State ◽

Undesirable State ◽

Parameter Dependent ◽

Levy Noise ◽

The Given

AbstractIn real systems, the unpredictable jump changes of the random environment can induce the critical transitions (CTs) between two non-adjacent states, which are more catastrophic. Taking an asymmetric Lévy-noise-induced tri-stable model with desirable, sub-desirable, and undesirable states as a prototype class of real systems, a prediction of the noise-induced CTs from the desirable state directly to the undesirable one is carried out. We first calculate the region that the current state of the given model is absorbed into the undesirable state based on the escape probability, which is named as the absorbed region. Then, a new concept of the parameter dependent basin of the unsafe regime (PDBUR) under the asymmetric Lévy noise is introduced. It is an efficient tool for approximately quantifying the ranges of the parameters, where the noise-induced CTs from the desirable state directly to the undesirable one may occur. More importantly, it may provide theoretical guidance for us to adopt some measures to avert a noise-induced catastrophic CT.

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