active vibration control

Hey all,
I am working on a an active vibration control progect with a cantilever beam, piezo electric actuator, and with a location measurments components.
but first i need to simulate the whole closed loop system.

So i have manged to export my simple cantilever beam system into matlab (comsol 3.5a), and i defind one input on the edge called u1, and in the middle of the beam i defind u2 and -u2 on two points to have a bending moment effect (simulating a piezo actuator), also a material has been defiend.

in matlab i worked with a LQR tutorial to find the right matrices.

first of all i want to ask if you think that this is the right way to simulate a LQR vibration control in matlab ?
what would you recommend to change in the comsol system (inputs perhaps?).

also i have a bit of a problem with the idea to define 2 inputs u1 u2 while the other is only a response to the first.
but this is what my head progect suggested.

at the end i just want to input a sinus force to activate the system, and to damp it with the bending moment.
my goal is to find the best place that i can put the actuator.

thank you for your help.

Eyal