Vulnerabilities of Cyber-Physical Linear Control Systems to Sophisticated Attacks

2017 ◽  
Author(s):  
Verica Radisavljevic-Gajic ◽  
Seri Park ◽  
Danai Chasaki
Keyword(s):  
Control System ◽  
Nonlinear Systems ◽  
Control Systems ◽  
Feedback Loops ◽  
Linear Control ◽  
Linear Control Systems ◽  
Malicious Attacks ◽  
Physical Systems ◽  
Controllability And Observability ◽  
Time Invariant

The purpose of this paper is to examine fundamentals of linear control systems and consider vulnerability of the main cyber physical control system features and concepts under malicious attacks, first of all, stability, controllability, and observability, design of feedback loops, design and placement of sensors and controllers. The detailed study is limited to the most important vulnerability issues in time-invariant, unconstrained, deterministic, linear physical systems. Several interesting and motivations examples are provided. We outline also some basic vulnerability studies for time-invariant nonlinear systems.

Contribution to Stability Control of Nonlinear Systems

2012 ◽  
Vol 463-464 ◽  
pp. 1579-1582
Author(s):  
Ivan Svarc ◽  
Radomil Matousek
Keyword(s):  
Nonlinear Systems ◽  
Control Systems ◽  
Small Region ◽  
Stability Control ◽  
Linear Control ◽  
Linear Control Systems ◽  
Engineering Practice ◽  
Constant Coefficients ◽  
Linear Differential ◽  
Actual Control

The most powerful methods of systems analysis have been developed for linear control systems. For a linear control system, all the relationships between the variables are linear differential equations, usually with constant coefficients. Actual control systems usually contain some nonlinear elements. In the following we show how the equations for nonlinear systems may be linearized. But the result is only applicable in a sufficiently small region in the neighbourhood of equilibrium point. The table in this paper includes the nonlinear equations and their the linear approximation. Then it is easy to find out if the nonlinear system is or is not stable; the task that usually ranks among the difficult tasks in engineering practice.

Symmetry Breaking of Periodic Orbits in Control Systems: A Harmonic Balance Approach

1998 ◽  
Vol 08 (12) ◽  
pp. 2439-2448 ◽  
Author(s):  
Baltazar Aguirre ◽  
Jose Alvarez-Ramírez ◽  
Rodolfo Suárez
Keyword(s):  
Control System ◽  
Symmetry Breaking ◽  
Control Systems ◽  
Periodic Orbits ◽  
Harmonic Balance ◽  
Three Dimensional ◽  
High Gain ◽  
Linear Control ◽  
Linear Control Systems ◽  
Dimensional Control

This work is concerned with linear control systems subjected to saturated feedback. A first harmonic approach is used to describe the existence of nonsymmetric periodic orbits in a three-dimensional control system. By taking a high-gain parametrization of the feedback control, the presence of nonsymmetric (first harmonic) periodic orbits is demonstrated for certain values of the parameter. Since it is also shown that nonsymmetric periodic orbits do not exist for small and large values of the parameter, evidences are found of the existence of symmetry breaking bifurcations.

scholarly journals Computing μ-Values for Real and Mixed μ Problems

Mathematics ◽  
2019 ◽  
Vol 7 (9) ◽  
pp. 821
Author(s):  
Mutti-Ur Rehman ◽  
Muhammad Tayyab ◽  
Muhammad Fazeel Anwar
Keyword(s):  
Control Systems ◽  
Numerical Computation ◽  
Feedback System ◽  
Feedback Loops ◽  
Linear Control ◽  
Linear Control Systems ◽  
Linear Feedback ◽  
Feedback Systems ◽  
Perturbed System ◽  
Stability And Instability

In various modern linear control systems, a common practice is to make use of control in the feedback loops which act as an important tool for linear feedback systems. Stability and instability analysis of a linear feedback system give the measure of perturbed system to be singular and non-singular. The main objective of this article is to discuss numerical computation of the μ -values bounds by using low ranked ordinary differential equations based technique. Numerical computations illustrate the behavior of the method and the spectrum of operators are then numerically analyzed.

Stability Criterion of Linear Control Systems with Time Delay

1970 ◽  
Vol 3 (3) ◽  
pp. 86-87 ◽  
Author(s):  
F. L. N-Nagy ◽  
M. N. Al-Tikriti
Keyword(s):  
Control System ◽  
Time Delay ◽  
Control Systems ◽  
Stability Criterion ◽  
Feedback Loop ◽  
Linear Control ◽  
Linear Control Systems ◽  
Loop Gain ◽  
Nyquist Stability ◽  
The Stability

The paper outlines the Nyquist stability criterion linear control systems with time delay, using frequency response results. The variation of the loop-gain and time delay are investigated when the time delay occurs in the forward-loop or the feedback-loop or both. The stability condition of a simple control system is used to illustrate the method.

Fractional Vector-Order h-Realisation of the Impulse Response Function

2020 ◽  
Vol 14 (2) ◽  
pp. 108-113
Author(s):  
Ewa Pawłuszewicz
Keyword(s):  
Control Systems ◽  
Impulse Response ◽  
Response Function ◽  
Impulse Response Function ◽  
Linear Control ◽  
Linear Control Systems

AbstractThe problem of realisation of linear control systems with the h–difference of Caputo-, Riemann–Liouville- and Grünwald–Letnikov-type fractional vector-order operators is studied. The problem of existing minimal realisation is discussed.

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