Lyapunov Stability for a Nonlinear, Time-varying system












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I am currently trying to learn how to determine the stability of a solution using Lyapunov's Method for non-autonomous systems.



Say we are given a nonlinear system:
$$dot{x_1}(t)=-x_1(t) + x_2(t)[x_1(t)+g(t)]$$
$$dot{x_2}(t)= x_1(t)[x_1(t)+g(t)]$$
And we want to investigate the stability of the solution $x(t)=0$.



If we use a simple Lyapunov function
$$V(x) = 0.5x_{1}^{2} + 0.5x_{2}^{2}$$



I can find $dot{V}(x,t)$, but I am unsure of where to go from here. How do I prove some kind of stability/instability. Do I need Barbalat's Lemma?










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$endgroup$












  • $begingroup$
    You could look at the case when $g(t)=0$ and if that is stable use vanishing perturbation.
    $endgroup$
    – Kwin van der Veen
    Dec 10 '18 at 9:43










  • $begingroup$
    I think you might have mistaken a $-$ sign with $+$
    $endgroup$
    – polfosol
    Feb 4 at 21:27
















3












$begingroup$


I am currently trying to learn how to determine the stability of a solution using Lyapunov's Method for non-autonomous systems.



Say we are given a nonlinear system:
$$dot{x_1}(t)=-x_1(t) + x_2(t)[x_1(t)+g(t)]$$
$$dot{x_2}(t)= x_1(t)[x_1(t)+g(t)]$$
And we want to investigate the stability of the solution $x(t)=0$.



If we use a simple Lyapunov function
$$V(x) = 0.5x_{1}^{2} + 0.5x_{2}^{2}$$



I can find $dot{V}(x,t)$, but I am unsure of where to go from here. How do I prove some kind of stability/instability. Do I need Barbalat's Lemma?










share|cite|improve this question











$endgroup$












  • $begingroup$
    You could look at the case when $g(t)=0$ and if that is stable use vanishing perturbation.
    $endgroup$
    – Kwin van der Veen
    Dec 10 '18 at 9:43










  • $begingroup$
    I think you might have mistaken a $-$ sign with $+$
    $endgroup$
    – polfosol
    Feb 4 at 21:27














3












3








3


1



$begingroup$


I am currently trying to learn how to determine the stability of a solution using Lyapunov's Method for non-autonomous systems.



Say we are given a nonlinear system:
$$dot{x_1}(t)=-x_1(t) + x_2(t)[x_1(t)+g(t)]$$
$$dot{x_2}(t)= x_1(t)[x_1(t)+g(t)]$$
And we want to investigate the stability of the solution $x(t)=0$.



If we use a simple Lyapunov function
$$V(x) = 0.5x_{1}^{2} + 0.5x_{2}^{2}$$



I can find $dot{V}(x,t)$, but I am unsure of where to go from here. How do I prove some kind of stability/instability. Do I need Barbalat's Lemma?










share|cite|improve this question











$endgroup$




I am currently trying to learn how to determine the stability of a solution using Lyapunov's Method for non-autonomous systems.



Say we are given a nonlinear system:
$$dot{x_1}(t)=-x_1(t) + x_2(t)[x_1(t)+g(t)]$$
$$dot{x_2}(t)= x_1(t)[x_1(t)+g(t)]$$
And we want to investigate the stability of the solution $x(t)=0$.



If we use a simple Lyapunov function
$$V(x) = 0.5x_{1}^{2} + 0.5x_{2}^{2}$$



I can find $dot{V}(x,t)$, but I am unsure of where to go from here. How do I prove some kind of stability/instability. Do I need Barbalat's Lemma?







control-theory nonlinear-system stability-theory non-linear-dynamics lyapunov-functions






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Dec 8 '18 at 7:19







Chemical Engineer

















asked Dec 8 '18 at 5:00









Chemical EngineerChemical Engineer

597




597












  • $begingroup$
    You could look at the case when $g(t)=0$ and if that is stable use vanishing perturbation.
    $endgroup$
    – Kwin van der Veen
    Dec 10 '18 at 9:43










  • $begingroup$
    I think you might have mistaken a $-$ sign with $+$
    $endgroup$
    – polfosol
    Feb 4 at 21:27


















  • $begingroup$
    You could look at the case when $g(t)=0$ and if that is stable use vanishing perturbation.
    $endgroup$
    – Kwin van der Veen
    Dec 10 '18 at 9:43










  • $begingroup$
    I think you might have mistaken a $-$ sign with $+$
    $endgroup$
    – polfosol
    Feb 4 at 21:27
















$begingroup$
You could look at the case when $g(t)=0$ and if that is stable use vanishing perturbation.
$endgroup$
– Kwin van der Veen
Dec 10 '18 at 9:43




$begingroup$
You could look at the case when $g(t)=0$ and if that is stable use vanishing perturbation.
$endgroup$
– Kwin van der Veen
Dec 10 '18 at 9:43












$begingroup$
I think you might have mistaken a $-$ sign with $+$
$endgroup$
– polfosol
Feb 4 at 21:27




$begingroup$
I think you might have mistaken a $-$ sign with $+$
$endgroup$
– polfosol
Feb 4 at 21:27










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