Linearizing ordinary differential equations

1 reply · 4K views · last reply
thavamaran
Messages
39
Reaction score
0
Hi guys, I am trying to linearize a coupled non-linear ode. I used partial derivative, and then jacobian matrix, i have seen paper using state-space model of jacobian matrix. I can't get a proper reference on this state-space model.

Attached is the non-linear ode, the partial derivative of the non-linear ode and the state-space model of jacobian matrix.

Can someone enhance or explain how they got the state-space model as the transformation, is it a fix formulation. Sorry for asking this way cause I can't find any books or reference referring or explaining this. Please help me! thanks!
 
Last edited:
This is the attachment.
 
Attachments
  • Three numbered differential equations (1) to (3): dN(t)/dt = I(t)/(q·V_a) − g₀[N(t) − N₀]·S(t)/(1 + ε·S(t)) − N(t)/τ_n; dS(t)/dt = Γ·g₀[N(t) − N₀]·S(t)/(1 + ε·S(t)) − S(t)/τ_p + Γ·β·N(t)/τ_n; dφ(t)/dt = ½α[Γ·g₀[N(t) − N₀] − 1/τ_p].
    jacobian 1.JPG
    10.4 KB · Views: 581
  • Equations (7) to (11): partial derivatives of dN/dt and dS/dt with respect to N and S, forming a Jacobian matrix in a state-space model with input I(t) and output y = [0 1][N S]^T.
    jacobian 2.JPG
    22.4 KB · Views: 516