- #1
james1234
- 19
- 0
Hi there!
I am just trying to work though a simple deriviation presented in a txt book (feedback control of dynamic systems p 616). I am REALLY new to linear algebra and they have skipped too many steps!
they have used the chain rule for differentiation of V(x) (a lyapunov function) where V = xTPx ; where P is a symetric positive matrix (i have not been able to find reference to a 'positive matrix'.. is a positive-definite matrix the same thing?)
Thus we have;
d[tex]/dt[/tex]xTPx = x[tex]\dot{}[/tex]TPx + xTPx[tex]\dot{}[/tex]
from there we somehow get to
xT(FTP + PF)x (where i believe F is the 'state' matrix usually represened as A ie X dot = Fx + bu )
if someone could point me in the right direction it would really be appreciated!
I am just trying to work though a simple deriviation presented in a txt book (feedback control of dynamic systems p 616). I am REALLY new to linear algebra and they have skipped too many steps!
they have used the chain rule for differentiation of V(x) (a lyapunov function) where V = xTPx ; where P is a symetric positive matrix (i have not been able to find reference to a 'positive matrix'.. is a positive-definite matrix the same thing?)
Thus we have;
d[tex]/dt[/tex]xTPx = x[tex]\dot{}[/tex]TPx + xTPx[tex]\dot{}[/tex]
from there we somehow get to
xT(FTP + PF)x (where i believe F is the 'state' matrix usually represened as A ie X dot = Fx + bu )
if someone could point me in the right direction it would really be appreciated!
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