Magnetic Levitation

calm_ajay

Hiii,
I m facing problem in my magnetic levitation plant(which is nonlinear plant-unstable).I linearized it (by using taylor series expansion) after that linear plant also unstable,so i used controller (based on control law : u = -kx) it stable the linear plant but when i applied this controller to nonlinear plant(with equilibrium points), it again showed that it is unstable .
I dont know wats going wrong .even i used controller with integrator(i same manner as above)but the result same.
for these thing s i used matlab+simulink.
can any body help me out this problem.

drasnor

If your nonlinear plant is unstable your linear plant had better be also. Did you linearize the plant about the point at which you intend to operate the plant? It sounds like you're designing a classical controller; are you checking your Bode magnitude/phase plots?

-drasnor

shwaip

moonspeak.