Why is the simulating result different from the MPC controller's scripts when I want to use mpc Strategy to control the stewart platform in simulink ?

To Whom It May Concern,

I am a beginner about simulink but some issues staring me in the face.So I'm writing to seek clarification regarding MPC Controller in simulink. Your assistance would be most valuable.

At the beginning, I wanted to use MPC strategy to control the stewart platform in simulink. With preliminary resarch, I chose to use MPC Controller in MPC Toolbox. When I finished the configuring process, something went wrong.

In MPC controller's scenario, the output results are stable as time going. However, when we run the stewart model with simulink, the model's state is deeply defferent from the results displayed in MPC Controller.

Could you tell me what mistakes I made in this process?

Yours faithfully,

Answer 1

[Ayush]

Hi Bingkun,

I understand your concern. The main reason for the difference is that the MPC Controller block typically uses a simplified (often linearized) model, while your Stewart platform in Simulink is likely nonlinear and more complex. This mismatch causes the controller to perform well in its own scenario but not on the actual plant.

To address this:

• Consider using Adaptive or Nonlinear MPC, which are designed for nonlinear or time-varying systems.
• Make sure your MPC prediction model closely matches your Simulink plant model.
• Double-check your signal connections and sampling times.

You can refer the following documentation to understand controlling non linear and time - varying model:

https://www.mathworks.com/help/releases/R2025a/mpc/gs/what-is-mpc.html#mw_7552558e-b393-4c2d-9e5c-8539313cdadd

If the issue still persists, you should contact MathWorks Technical support at:

https://www.mathworks.com/support/contact_us.html

Hope this helps!