Qualitative Robustness and Its Role in the Robust Control of Uncertain Engineering Systems

2011 ◽  
Author(s):  
Nagini Devarakonda ◽  
Rama K. Yedavalli
Keyword(s):  
Control Systems ◽  
Uncertain Systems ◽  
Closed Loop ◽  
Quantitative Information ◽  
Engineering Systems ◽  
Closed Loop System ◽  
Qualitative Information ◽  
Loop Control ◽  
Qualitative Robustness ◽  
Ecological Principles

This paper addresses the issue of robustness of linear uncertain systems. In addition to the conventional notion of robustness based on quantitative information, in this paper, a new and novel perspective of qualitative robustness is introduced. The qualitative robustness measure is inspired by ecological principles and is based on the nature of interactions and interconnections of the system. Thus, using the proposed framework, the robustness of engineering systems can be assessed both from quantitative as well as qualitative information. This type of analysis from both viewpoints sheds considerable insight on the desirable nominal system in engineering applications. Using these concepts it is shown that a specific quantitative set of matrices labeled ‘Target Sign Stable Matrices’ are the best nominal matrices. These concepts are then extended to closed loop control systems and problem of control design and for ease in design a new set of matrices ‘Target Pseudosymmetric Matrices’ are introduced which enhance the class of desirable closed loop system matrices. Examples are included to illustrate these concepts.

Determination of Most Desirable Nominal Closed-Loop State Space System Via Qualitative Ecological Principles

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
Nagini Devarakonda ◽  
Rama K. Yedavalli
Keyword(s):  
State Space ◽  
Closed Loop ◽  
Point Of View ◽  
Loop System ◽  
Matrix Structure ◽  
System Matrix ◽  
Closed Loop System ◽  
Qualitative Robustness ◽  
Ecological Principles ◽  
Linear State

This paper addresses the issue of determining the most desirable “nominal closed-loop matrix” structure in linear state space systems, from stability robustness point of view, by combining the concepts of “quantitative robustness” and “qualitative robustness.” The qualitative robustness measure is based on the nature of interactions and interconnections of the system. The quantitative robustness is based on the nature of eigenvalue/eigenvector structure of the system. This type of analysis from both viewpoints sheds considerable insight on the desirable nominal system in engineering applications. Using these concepts, it is shown that three classes of quantitative matrices labeled “target sign stable (TSS) matrices,” “target pseudosymmetric (TPS) matrices,” and finally “quantitative ecological stable (QES) matrices” have features which qualify them as the most desirable nominal closed-loop system matrices. In this paper, we elaborate on the special features of these sets of matrices and justify why these classes of matrices are well suited to be the most desirable nominal closed-loop matrices in the linear state space framework. Establishment of this most desirable nominal closed-loop system matrix structure paves the way for designing controllers which qualify as robust controllers for linear systems with real parameter uncertainty. The proposed concepts are illustrated with many useful examples.

EEG-FES-Force-MMG closed-loop control systems of a volunteer with paraplegia considering motor imagery with fatigue recognition and automatic shut-off

2021 ◽  
Vol 68 ◽  
pp. 102662
Author(s):  
Paulo Broniera Junior ◽  
Daniel Prado Campos ◽  
André Eugenio Lazzaretti ◽  
Percy Nohama ◽  
Aparecido Augusto Carvalho ◽  
...  
Keyword(s):  
Control Systems ◽  
Motor Imagery ◽  
Closed Loop ◽  
Closed Loop Control ◽  
Loop Control

Linear Control Root-Clustering of Uncertain Systems

2014 ◽  
Author(s):  
S. Gutman
Keyword(s):  
Control Systems ◽  
Uncertain Systems ◽  
Closed Loop ◽  
Linear Control ◽  
Linear Control Systems ◽  
Linear Feedback ◽  
Important Class ◽  
Linear Feedback Control ◽  
Control Root ◽  
Clustering Criterion

In the design of linear control systems, it is desired to assign the closed loop spectrum in sub-regions (as opposed to locations) of the complex plane. The present paper establishes a matrix root-clustering criterion for an important class of regions, and develops a linear feedback control that assigns the closed loop spectrum in the desired region. This is done for both nominal and uncertain systems.

A Control Strategy for Intelligent Stamp Forming Tooling

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
William J. Emblom ◽  
Klaus J. Weinmann
Keyword(s):  
Fuzzy Logic ◽  
Control Systems ◽  
Control Strategy ◽  
Pid Controller ◽  
Closed Loop ◽  
Closed Loop Control ◽  
Linear Quadratic ◽  
Blank Holder ◽  
Loop Control ◽  
Stamp Forming

This paper describes the development and implementation of closed-loop control for oval stamp forming tooling using MATLAB®’s SIMULINK® and the dSPACE®CONTROLDESK®. A traditional PID controller was used for the blank holder pressure and an advanced controller utilizing fuzzy logic combining a linear quadratic gauss controller and a bang–bang controller was used to control draw bead position. The draw beads were used to control local forces near the draw beads. The blank holder pressures were used to control both wrinkling and local forces during forming. It was shown that a complex, advanced controller could be modeled using MATLAB’s SIMULINK and implemented in DSPACE CONTROLDESK. The resulting control systems for blank holder pressures and draw beads were used to control simultaneously local punch forces and wrinkling during the forming operation thereby resulting in a complex control strategy that could be used to improve the robustness of the stamp forming processes.

scholarly journals Design of delay observer-based controllers for uncertain time-lag systems

1999 ◽  
Vol 5 (2) ◽  
pp. 121-137 ◽  
Author(s):  
Magdi S. Mahmoud ◽  
Mohamed Zribi
Keyword(s):  
Uncertain Systems ◽  
Closed Loop ◽  
Time Lag ◽  
Linear Matrix ◽  
Time Lags ◽  
Matrix Inequalities ◽  
Closed Loop System ◽  
Delayed Measurements ◽  
Uncertain Time ◽  
Theoretical Developments

In this paper, the problem of designing observers and observer-based controllers for a class of uncertain systems with input and state time lags is considered. We construct delay-type observers in which both the instantaneous as well as the delayed measurements are utilized. Using feedback control based on the reconstructed state, the behavior of the closed-loop system is investigated. It is established that the uncertain time-lag system with delay observer-based control is asymptotically stable. Expressions for the gain matrices are given based on two linear-matrix inequalities. A numerical example is given to illustrate the theoretical developments.

Tangible Programming for Basic Control System New Frameworks to Engineering Education for Children

2014 ◽  
Vol 931-932 ◽  
pp. 1298-1302
Author(s):  
Thiang Meadthaisong ◽  
Siwaporn Meadthaisong ◽  
Sarawut Chaowaskoo
Keyword(s):  
Control System ◽  
Engineering Education ◽  
Control Systems ◽  
Primary Schools ◽  
Closed Loop ◽  
Open Loop ◽  
Closed Loop Control ◽  
College Level ◽  
Loop Control ◽  
Tangible Programming

Programming control in industrial design is by its nature expert upon an example being Programmable Logic Controller (PLC). Such programmes are unsuitable for children or novices as they cannot understand how to use the programme. This research seeks to present tangible programming for a basic control system in new frameworks in engineering education for children. Such programmes could be for use in kindergartens, primary schools or general teaching where knowledge about basic control is required. Normally open-loop and closed-loop control system programming is taught at university and college level. This may be late as far as acquiring knowledge of basic control systems is concerned. Using tangible programming without a computer but instructions and interface, relay and motor could result in children in kindergartens and primary schools being able to programme open-looped control systems which mix chemicals or closed-loop control systems which control conveyor belts. However, the children would not be able to undertake programming using programmable control in a similar scenario.

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