Simulink Model Predictive Control

Why does simulinks model predictive controller (MPC) respond 1 frame late to my reference signal?

This is a discrete time system with a very simple model (mass-spring-damper).

Does the MPC only try to match the future output with the current reference input? I would have thought that the MPC could follow the reference signal exactly using Bang-Bang control if I didn't constrain the controls.

Trying to keep the questions simple. Please let me know if more details are needed. Thank you in advance!

Answer 1

[Dhruv Thakkar]

Hey, have you tried reducing the timestep and tuning the prediciton horizon and control horizon. And if its a MIMO system try tuning the weights also.

Let me know if anything works out.

[eddie ball]

Hello Dhruv Thakkar,

Thanks for the reply. I have played with thos parameters but no matter what I seem to do, I can't get the output to match the reference exactly. I assumed for such a simple system (where the reference model is exactly the plant model (i.e. linear)) this would be trivial.

Respectfully,

Eddie