problem with MPC controller

Question

Xu 2023-1-12

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1892945-problem-with-mpc-controller

回答： Emmanouil Tzorakoleftherakis 2023-1-25

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Hi I am Xu and now I wanna use adaptive MPC controller to control a LPV system. It is a thermal control and the Ty is the controlled temperature and Ic the the input current to LPV. The 'Model' parameter will be generated from LPV system with output state space, states and outputs and U, DX will from the matrix and states calculated. The refference temperature is set to 363.15 K and in attachment are the Ty and Ic in 3100s to 3500s. It shows that, if the Ty is higher than 363.15 the Ic will fall rapidly to 0; if the Ty is lower than 363.15 the Ic will increase rapidly to a value. As in such period Ty go through 363.15 for many times and the Ic rapidly ad and down. It is dangerous for the control. Could anyone give me tips to solve such a problem? Thank you very much!

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Sam Chak 2023-1-13

Hi @Xu

I would probably analyze the thermal system to see if the temperature can regulated with a standard feedback control.

If it works, then I will gather some data to design the advanced controller within certain constraints and then replace it with the advanced controller.

Can you show the mathematical model of the LPV thermal system?

Xu 2023-1-13

Thanks for your answer! Indeed I also designed a PID controller and it seems better than the MPC model. Such a rapidly ab and down may be caused by, that even the temperature changes 0.01 K the output must change 1e4 W(I am not sure about this unit), so when the Ty is near 363.15 K the output of MPC controller changes with very high amplitude and frequency. What do you mean the mathematical model, the state space?

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Answer 1

Emmanouil Tzorakoleftherakis 2023-1-25

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1892945-problem-with-mpc-controller#answer_1156155

It seems to me that the solution is to add a constraint on the rate of change of the manipulated variable Ic. That way you can avoid rapid changes in the input current. Please take a look at this doc page to see how to set up rate constraints