MPC closed-loop identification without excitation

• Published in: Journal of process control 2021-10, Vol.106, p.122-129
• Main Authors: Zhu, Yun, Yan, Wengang, Zhu, Yucai
• Format: Article
• Language: English
• Subjects: Closed-loop test; Data informativity; Model predictive control; System identification
• ISSN: 0959-1524; 1873-2771
• DOI: 10.1016/j.jprocont.2021.08.018

This paper presents a method of closed-loop identification for multivariable systems without external excitation. The method is specially designed for model predictive control (MPC) systems. Without using external excitation (test signals), the method ensures the informativity of the closed-loop data and, at the same time, improve the control performance during the test period. The purpose of the study is to reduce the cost of identification test. The basic idea is to switch the input weighting matrix in the MPC controller which leads to the informativity of the data-set. A preliminary test is carried out in order to find a new input weighting matrix which improve the control performance; then a switching scheme is developed based on the two weighting matrices. Traditional simulation based model validation no longer works in closed-loop identification without excitation, and model error bounds on the frequency responses can be used instead. The effectiveness of the proposed method is demonstrated by a simulation study. •A method of an MPC closed-loop identification without excitation is developed.•The method ensures the informativity and improves the control performance during the test.•The method uses input weighting switching to ensures the informativity of the data-set.•The simulation based model validation no longer works and model error bounds can be used instead.