Matching the principal deformation mode method with the probability transformation method for the analysis of uncertain systems

2019 ◽  
Vol 118 (7) ◽  
pp. 395-410 ◽  
Author(s):  
G. Falsone ◽  
R. Laudani
Keyword(s):  
Uncertain Systems ◽  
Deformation Mode ◽  
Transformation Method ◽  
Probability Transformation ◽  
Mode Method

A probability transformation method (PTM) for the dynamic stochastic response of structures with non-Gaussian excitations

2018 ◽  
Vol 35 (5) ◽  
pp. 1978-1997 ◽  
Author(s):  
Giovanni Falsone ◽  
Rossella Laudani
Keyword(s):  
Design Methodology ◽  
Fundamental Property ◽  
Transformation Method ◽  
Computational Effort ◽  
Content Type ◽  
Probabilistic Characterization ◽  
Probability Transformation ◽  
Dynamic Stochastic ◽  
Non Gaussian

Purpose This paper aims to present an approach for the probabilistic characterization of the response of linear structural systems subjected to random time-dependent non-Gaussian actions. Design/methodology/approach Its fundamental property is working directly on the probability density functions of the actions and responses. This avoids passing through the evaluation of the response statistical moments or cumulants, reducing the computational effort in a consistent measure. Findings It is an efficient method, for both its computational effort and its accuracy, above all when the input and output processes are strongly non-Gaussian. Originality/value This approach can be considered as a dynamic generalization of the probability transformation method recently used for static applications.

Simplifying Robust Control Designs of Parametric Uncertain Systems Using Dimensional Transformations

2005 ◽  
Author(s):  
Haftay Hailu ◽  
Sean Brennan
Keyword(s):  
Robust Control ◽  
Uncertain Systems ◽  
Transformation Method ◽  
Control Synthesis ◽  
Synthesis Methods ◽  
Equivalent Representation ◽  
Control Techniques ◽  
Single Controller ◽  
Robust Control Design ◽  
Control Designs

Robust control techniques have become more popular in the last decade because of their ability to construct a single controller suitable for a family of plants that are represented as a nominal plant with an uncertainty bounds. A typical challenge with robust control design is that, as the size of the uncertainty block gets bigger, the complexity of the control synthesis and resulting controller exponentially increases. Using a dimensional transformation method, this work shows that some robust control problems can be recast into an equivalent representation with a much smaller size of uncertainty block. This reduction potentially reduces the conservativeness and computational complexity of both H∞/μ – synthesis methods. This method is demonstrated using the 1990 ACC benchmark problem.

Research on Ultimate Bearing Capacity of Coupler Steel Tube Falsework with Initial Defect

2010 ◽  
Vol 163-167 ◽  
pp. 32-35 ◽  
Author(s):  
Chang Ming Hu ◽  
Zhao Shen Ge ◽  
Wang Jing
Keyword(s):  
Kinematic Hardening ◽  
Defect Mode ◽  
Deformation Mode ◽  
Steel Tube ◽  
Displacement Curve ◽  
Test Model ◽  
Material Characteristic ◽  
Finite Element Software ◽  
Mode Method ◽  
Sensitive Structure

Used of finite element software, based on the material characteristic and node semi-rigid experimentations, the model with material multi-linear kinematic hardening and node semi-rigid was established to simulate the test model of coupler steel tube falsework. According to the measured data of the defect, to analyze the nonlinear stability of the model by methods of the consistent defect mode and stochastic defect, the results indicate that the model’s correctness and consistent mode imperfection method’s in analyzing coupler steel tube falsework is feasible, and the structure is a defect-sensitive structure. The brittleness failure characteristic of coupler steel tube falsework was validated and several effective conclusions were educed after comparative study on the deformation mode and load-displacement curve of the test, consistent defect mode method and stochastic defect method.

Non-Linear Free Vibrations of a Rotating Beam Carrying a Tip Mass With Rotary Inertia

2002 ◽  
Author(s):  
Ahmad A. Al-Qaisia
Keyword(s):  
Transformation Method ◽  
Free Vibrations ◽  
Rotary Inertia ◽  
Inertia Effects ◽  
Assumed Mode Method ◽  
Non Linear ◽  
Mode Method ◽  
Geometric Stiffening ◽  
Tip Mass ◽  
Root Attachment

The non-linear, for each of the first three modes, of planar, large amplitude flexural free vibrations of a beam clamped with an angle to a rigid rotating hub and carrying a tip mass with rotary inertia are investigated. The shear deformation and rotary inertia effects are assumed to be negligible, but account is taken of axial inertia, non-linear curvature and the inextensibility condition. The Lagrangian dynamics in conjunction with the assumed mode method, assuming constant hub rotation speed, is utilized in deriving the non-linear unimodal temporal problem. The time transformation method is employed to obtain an approximate solution to the frequency-amplitude relation of the beam-mass free vibration, since the order of the nonlinear terms is not small which includes static and inertial geometric stiffening as well as inertial softening terms. Results in non-dimensional form are presented graphically, for the effect beam root-attachment angle, hub radius and the attached inertia element ratio on the variation of the natural frequency with vibration amplitude.

scholarly journals Adaptive Sliding Mode Fault-Tolerant Control for Uncertain Systems with Time Delay

2020 ◽  
Vol 14 (2) ◽  
pp. 337-345
Author(s):  
Pu Yang ◽  
Zhangxi Liu ◽  
Yuxia Wang ◽  
Dejie Li ◽  
◽  
...  
Keyword(s):  
Time Delay ◽  
Uncertain Systems ◽  
Position Control ◽  
Fault Tolerant ◽  
Sliding Mode ◽  
Fault Detection And Isolation ◽  
Sliding Surface ◽  
Adaptive Sliding Mode ◽  
Mode Method ◽  
Sliding Dynamics

In this work, an adaptive sliding mode fault-tolerant controller is proposed for a class of uncertain systems with time delay. The integral term is added to the traditional sliding surface to improve the robustness of the control system, and then a type of special sliding surface is designed to cancel the reaching mode based on global sliding mode method. Without the need for fault detection and isolation, an adaptive law is proposed to estimate the value of actuator faults, and an adaptive sliding mode fault-tolerant controller is designed to guarantee the asymptotic stability of sliding dynamics. Finally, the presented control scheme is applied to the position control of a Qball-X4 quad-rotor UAV model to verify the effectiveness.

scholarly journals Decision making with consonant belief functions: Discrepancy resulting with the probability transformation method used

2014 ◽  
Vol 24 (3) ◽  
pp. 359-370 ◽  
Author(s):  
Esma Cinicioglu
Keyword(s):  
Decision Making ◽  
Probability Distributions ◽  
Belief Function ◽  
Transformation Method ◽  
Research Society ◽  
Belief Functions ◽  
Belief Function Theory ◽  
Probability Transformation ◽  
Theory Of Belief Functions ◽  
Transformation Methods

Dempster?Shafer belief function theory can address a wider class of uncertainty than the standard probability theory does, and this fact appeals the researchers in operations research society for potential application areas. However, the lack of a decision theory of belief functions gives rise to the need to use the probability transformation methods for decision making. For representation of statistical evidence, the class of consonant belief functions is used which is not closed under Dempster?s rule of combination but is closed under Walley?s rule of combination. In this research, it is shown that the outcomes obtained using both Dempster?s and Walley?s rules do result in different probability distributions when pignistic transformation is used. However, when plausibility transformation is used, they do result in the same probability distribution. This result shows that the choice of the combination rule and probability transformation method may have a significant effect on decision making since it may change the choice of the decision alternative selected. This result is illustrated via an example of missile type identification.

Sign in / Sign up

Export Citation Format

Share Document