Adaptive control for discontinuous variable-order fractional systems with disturbances

2021 ◽  
Author(s):  
Xiao Peng ◽  
Yijing Wang ◽  
Zhiqiang Zuo
Keyword(s):  
Adaptive Control ◽  
Variable Order ◽  
Fractional Systems

Variable order fractional systems

2019 ◽  
Vol 71 ◽  
pp. 231-243 ◽  
Author(s):  
Manuel D. Ortigueira ◽  
Duarte Valério ◽  
J. Tenreiro Machado
Keyword(s):  
Variable Order ◽  
Fractional Systems

The Effect of Computational Delay on Performance of Adaptive Control Systems

2006 ◽  
Author(s):  
Pawel Konrad Orzechowski ◽  
Tsu-Chin Tsao ◽  
James Steve Gibson
Keyword(s):  
Adaptive Control ◽  
Least Squares ◽  
Adaptive Filters ◽  
Adaptive Controller ◽  
Recursive Least Squares ◽  
Variable Order ◽  
Stochastic Disturbance ◽  
Disturbance Dynamics ◽  
Fractional Delay ◽  
Computationally Intensive

In many adaptive control applications, especially where the recursive-least-squares (RLS) algorithms are used, the real-time implementation of high order adaptive filters for estimating the disturbance dynamics is computationally intensive. The delay associated with the computational burden is usually either underestimated as no delay or overestimated as one sample delay in the control system design and analysis. For a stochastic disturbance dynamics, the H2 optimal control performance for the case of one-step delay is worse than that of no delay due to the nonminimum phase plant zero introduced by the delay. The optimal performance for a fractional delay is bounded between these two extremes. The paper investigates the effect of the fractional computational delay on a variable order adaptive controller based on a recursive least-squares adaptive lattice filter. The trade-off between the adaptive filter order and the computational delay is analyzed and evaluated by an example.

Laser beam tracking by repetitive and variable-order adaptive control

2008 ◽  
Author(s):  
Chi-Ying Lin ◽  
Yen-Cheng Chen ◽  
Tsu-Chin Tsao ◽  
Steve Gibson
Keyword(s):  
Adaptive Control ◽  
Laser Beam ◽  
Variable Order ◽  
Beam Tracking

scholarly journals GENAVOS: A New Tool for Modelling and Analyzing Cancer Gene Regulatory Networks Using Delayed Nonlinear Variable Order Fractional System

2020 ◽  
Author(s):  
Hanif Yaghoobi ◽  
Keivan Maghooli ◽  
Masoud Asadi-Khiavi ◽  
Nader Jafarnia Dabanloo
Keyword(s):  
Gene Expression ◽  
Cancer Cell ◽  
Gene Regulatory Networks ◽  
Regulatory Networks ◽  
Time Series Data ◽  
Cell System ◽  
Series Data ◽  
Variable Order ◽  
Fractional Systems ◽  
Gene Regulatory

Complex diseases such as cancer are caused by changes in the Gene Regulatory Networks. Systems that model the complex dynamics of these networks along with adapting to real gene expression data are closer to reality and can help understand the creation and treatment of cancer. In this paper, for the first time, modelling of gene regulatory networks is performed using delayed nonlinear variable order fractional systems in the state space by a new tool called GENAVOS. This tool uses gene expression time series data to identify and optimize system parameters. This software has several tools for analyzing system dynamics. The results show that the nonlinear variable order fractional systems have very good flexibility in adapting to real data. We found that regulatory networks in cancer cells actually have a larger delay parameter than in normal cells. It is also possible to create chaos, periodic and quasi-periodic oscillations by changing the delay, degradation and synthesis rates. Our findings indicate a profound effect of time-varying order on these networks, which may be related to a type of cellular memory due to epigenetic and environmental factors. We showed that by changing the delay parameter and the variable order function for a normal cell system, its behavior changes and becomes quite similar to the behavior of a cancer cell. This work also confirms the effective role of the miR-17-92 cluster in the cancer cell cycle. GENAVOS is available at https://github.com/hanif-y/GENAVOS with its user guide and MATLAB codes.

scholarly journals Duality of variable fractional order difference operators and its application in identification

2014 ◽  
Vol 62 (4) ◽  
pp. 809-815 ◽  
Author(s):  
D. Sierociuk ◽  
M. Twardy
Keyword(s):  
System Identification ◽  
Least Squares ◽  
Fractional Order ◽  
Least Squares Estimation ◽  
Difference Operators ◽  
Variable Order ◽  
Fractional Systems ◽  
Order Difference

Abstract The paper presents a number of definitions of variable order difference and discusses duality among some of them. The duality is used to improve the performance of the least squares estimation when applied to variable order difference fractional systems. It turns out, that by appropriate exploitation of duality one can reduce the estimator variance when system identification is carried out.

Sign in / Sign up

Export Citation Format

Share Document