Perturbation Theory Based Robust Design Under Model Uncertainty

2009 ◽  
Vol 131 (11) ◽  
Author(s):  
XinJiang Lu ◽  
Han-Xiong Li
Keyword(s):  
Perturbation Theory ◽  
Robust Design ◽  
Model Uncertainty ◽  
Design Method ◽  
Matrix Perturbation ◽  
Nominal Model ◽  
Design Variables ◽  
The Matrix ◽  
System Robustness ◽  
And Control

In real-world applications, a nominal model is usually used to approximate the practical system for design and control. This approximation may make the traditional robust design less effective because the model uncertainty still affects the system performance. In this paper, a novel robust design approach is proposed to improve the system robustness to the variations in design variables as well as the model uncertainty. The proposed robust design consists of two separate optimizations. One is to minimize the variation effects of the design variables to the performance based on the nominal model just as what the traditional deterministic robust design methods do. The other is to minimize the effect of the model uncertainty using the matrix perturbation theory. Through solving a multi-objective optimization problem, the proposed design can improve the system robustness to the uncertainty. Simulation examples have demonstrated the effectiveness of the proposed design method.

Robust Design for Dynamic System Under Model Uncertainty

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
XinJiang Lu ◽  
Han-Xiong Li
Keyword(s):  
Robust Design ◽  
Model Uncertainty ◽  
Design Space ◽  
Design Method ◽  
Performance Constraints ◽  
Nominal Model ◽  
Traditional Design ◽  
Design Variables ◽  
Real World Applications ◽  
Robust Design Method

In real-world applications, a nominal model is often used to approximate the design of an industrial system. This approximation could make the traditional design method less effective due to the existence of model uncertainty. In this paper, a novel stability-based approach is proposed to design the system ensuring robust stability under model uncertainty. First, the design variables and their variation bounds are configured to make the system stable. Then, a robust design is developed to incorporate system eigenvalues that are less sensitive to model uncertainty. Finally, the tolerance of the design space will be maximized under given performance constraints. A simulation example is conducted to demonstrate the effectiveness of the proposed robust design method.

Data-Compensation Based Dynamic Robust Design for Partially Unknown System

2011 ◽  
Vol 311-313 ◽  
pp. 1168-1172
Author(s):  
Xin Jiang Lu ◽  
Ming Hui Huang ◽  
Min Chen ◽  
Yi Bo Li
Keyword(s):  
Robust Design ◽  
Model Uncertainty ◽  
Design Method ◽  
Industrial System ◽  
Practical Application ◽  
Nominal Model ◽  
Traditional Design ◽  
Unknown System ◽  
Robust Design Method ◽  
Uncertainty Compensation

In practical application, a nominal model is often used to approximate the design of industrial system. This approximation could make the traditional design method less effective due to the existence of model uncertainty. In this paper, a novel robust design approach is proposed to design the robustness of the dynamic system under model uncertainty. The key idea of this proposed method is that it integrates the advantages of both the model-based dynamic robust design and the data-based uncertainty compensation. A simulation example is conducted to demonstrate the effectiveness of the proposed robust design method.

A time-varying reliability-based robust design method considering overall efficiency of axial piston pump

2021 ◽  
pp. 1748006X2110661
Author(s):  
Zunling Du ◽  
Yimin Zhang
Keyword(s):  
Energy Conversion ◽  
Robust Design ◽  
Design Method ◽  
Design Stage ◽  
Structure Parameters ◽  
Time Varying ◽  
Design Variables ◽  
Reliability Method ◽  
Overall Efficiency ◽  
Axial Piston

Axial piston pumps (APPs) are the core energy conversion components in a hydraulic transmission system. Energy conversion efficiency is critically important for the performance and energy-saving of the pumps. In this paper, a time-varying reliability design method for the overall efficiency of APPs was established. The theoretical and practical instantaneous torque and flow rate of the whole APP were derived through comprehensive analysis of a single piston-slipper group. Moreover, as a case study, the developed model for the instantaneous overall efficiency was verified with a PPV103-10 pump from HYDAC. The time-variation of reliability for the pump was revealed by a fourth-order moment technique considering the randomness of working conditions and structure parameters, and the proposed reliability method was validated by Monte Carlo simulation. The effects of the mean values and variance sensitivity of random variables on the overall efficiency reliability were analyzed. Furthermore, the optimized time point and design variables were selected. The optimal structure parameters were obtained to meet the reliability requirement and the sensitivity of design variables was significantly reduced through the reliability-based robust design. The proposed method provides a theoretical basis for designers to improve the overall efficiency of APPs in the design stage.

Robust Design of Structures with Uncertain Parameters and Frequency Constraints Using Non-Probabilistic Methods

2014 ◽  
Vol 936 ◽  
pp. 1479-1484
Author(s):  
Ji Yun Chen ◽  
Yan Luo ◽  
Dong Huan Liu
Keyword(s):  
Robust Design ◽  
Measurement Errors ◽  
Design Method ◽  
Probabilistic Methods ◽  
Structural Performance ◽  
Stochastic Methods ◽  
Uncertain Parameters ◽  
Vibration Frequencies ◽  
Design Variables ◽  
Robust Design Method

The structural physical properties are often uncertain due to manufacture errors, measurement errors and other factors. Consequently, the vibration frequencies and corresponding eigenvectors are also uncertain. Robust design selects suitable design variables so that structural performance is insensitive to the various causes of variation without eliminating possible variations of variables. In practice robust design methods can be classified into probabilistic methods and non-probabilistic methods respectively. A new non-probabilistic robust design method based on the set theoretical convex method is presented in the present paper. The method not only inherits the advantages of existing non-stochastic methods, but also conquers the disadvantages of these methods.

A Procedure for Robust Design: Minimizing Variations Caused by Noise Factors and Control Factors

1996 ◽  
Vol 118 (4) ◽  
pp. 478-485 ◽  
Author(s):  
Wei Chen ◽  
J. K. Allen ◽  
Kwok-Leung Tsui ◽  
F. Mistree
Keyword(s):  
Robust Design ◽  
Irrigation System ◽  
Small Variation ◽  
Type I ◽  
Closed Form Solutions ◽  
Control Factors ◽  
Design Variables ◽  
Solar Powered ◽  
And Control ◽  
Noise Factors

In this paper, we introduce a small variation to current approaches broadly called Taguchi Robust Design Methods. In these methods, there are two broad categories of problems associated with simultaneously minimizing performance variations and bringing the mean on target, namely, Type I—minimizing variations in performance caused by variations in noise factors (uncontrollable parameters). Type II—minimizing variations in performance caused by variations in control factors (design variables). In this paper, we introduce a variation to the existing approaches to solve both types of problems. This variation embodies the integration of the Response Surface Methodology (RSM) with the compromise Decision Support Problem (DSP). Our approach is especially useful for design problems where there are no closed-form solutions and system performance is computationally expensive to evaluate. The design of a solar powered irrigation system is used as an example.

The Robust Design of Four-Bar Linkage with Clearance Based on Sensitivity Analysis

2010 ◽  
Vol 34-35 ◽  
pp. 1656-1660 ◽  
Author(s):  
Ying Cai Yuan ◽  
Yi Lun Liu ◽  
Yan Li
Keyword(s):  
Sensitivity Analysis ◽  
Mechanical System ◽  
Robust Design ◽  
Optimization Design ◽  
Design Method ◽  
Dynamic Performance ◽  
Nonlinear Dynamic Model ◽  
The Stability ◽  
And Control ◽  
Four Bar Linkage

Clearance is inevitable，so, with the increasing of machine’s speed, nonlinear vibration phenomenon caused by clearance is more apparent, which influences the precision and stability of mechanical system. For increasing the stability of mechanical system, a robust design method based on sensitivity analysis is studied, by using four-bar linkage as the research object, deducing the nonlinear dynamic model with clearance and the sensitivity of dynamic response, based on the rational planning to the tracks and control the sensitivities. In the design example, it shows that although the track deviation of robust design is slightly bigger than that of optimization design, the comprehensive dynamic performance of the mechanical system is much better than the latter, which means the stability of mechanical system is improved greatly. Thus, the robust design based on sensitivity analysis is an effective way to improve the stability of the mechanical system.

scholarly journals Method for designing multi-input system identification signals using a compact time-frequency representation

2021 ◽  
Author(s):  
Mathias Stefan Roeser ◽  
Nicolas Fezans
Keyword(s):  
System Identification ◽  
Design Method ◽  
Flight Test ◽  
Compact Representation ◽  
Time Frequency ◽  
Stability And Control ◽  
Frequency Representation ◽  
Aerodynamic Parameters ◽  
Definition Of ◽  
And Control

AbstractA flight test campaign for system identification is a costly and time-consuming task. Models derived from wind tunnel experiments and CFD calculations must be validated and/or updated with flight data to match the real aircraft stability and control characteristics. Classical maneuvers for system identification are mostly one-surface-at-a-time inputs and need to be performed several times at each flight condition. Various methods for defining very rich multi-axis maneuvers, for instance based on multisine/sum of sines signals, already exist. A new design method based on the wavelet transform allowing the definition of multi-axis inputs in the time-frequency domain has been developed. The compact representation chosen allows the user to define fairly complex maneuvers with very few parameters. This method is demonstrated using simulated flight test data from a high-quality Airbus A320 dynamic model. System identification is then performed with this data, and the results show that aerodynamic parameters can still be accurately estimated from these fairly simple multi-axis maneuvers.

scholarly journals Chiral correlators in $$ \mathcal{N} $$ = 2 superconformal quivers

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Francesco Galvagno ◽  
Michelangelo Preti
Keyword(s):  
Field Theory ◽  
Perturbation Theory ◽  
Flat Space ◽  
Field Theories ◽  
Superconformal Field Theories ◽  
Four Dimensions ◽  
Yang Mills ◽  
The Matrix ◽  
Superspace Formalism ◽  
Model Approach

Abstract We consider a family of $$ \mathcal{N} $$ N = 2 superconformal field theories in four dimensions, defined as ℤq orbifolds of $$ \mathcal{N} $$ N = 4 Super Yang-Mills theory. We compute the chiral/anti-chiral correlation functions at a perturbative level, using both the matrix model approach arising from supersymmetric localisation on the four-sphere and explicit field theory calculations on the flat space using the $$ \mathcal{N} $$ N = 1 superspace formalism. We implement a highly efficient algorithm to produce a large number of results for finite values of N , exploiting the symmetries of the quiver to reduce the complexity of the mixing between the operators. Finally the interplay with the field theory calculations allows to isolate special observables which deviate from $$ \mathcal{N} $$ N = 4 only at high orders in perturbation theory.

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