Global robust output regulation of a class of MIMO nonlinear systems by nonlinear internal model control

• Published in: International journal of robust and nonlinear control 2021-06, Vol.31 (9), p.4037-4051
• Main Authors: Ping, Zhaowu, Li, Yaoyi, Huang, Yunzhi, Lu, Jun‐Guo, Wang, Hai
• Format: Article
• Language: English
• Subjects: Control systems design; Control theory; Feedback control; MIMO (control systems); MIMO nonlinear systems; Nonlinear control; nonlinear internal model; Nonlinear systems; output regulation; Robust control; Robust stabilization; State feedback
• ISSN: 1049-8923; 1099-1239
• DOI: 10.1002/rnc.5456

Recently, the global robust output regulation problem for a class of uncertain multi‐input multi‐output (MIMO) nonlinear systems which may not have well‐defined relative degree and are subject to a nonlinear exosystem has been studied based on a constructive nonlinear internal model. However, the proposed nonlinear internal model‐based control law is applicable to the case where the exogenous signals are reference input and/or measurable disturbance rather than unmeasurable disturbance. For this reason, this paper further studies the same control problem based on a general nonlinear internal model independent of the exogenous signal. It is shown that this control problem can be converted into a global robust stabilization problem of a more complicated MIMO nonlinear system with various uncertainties and well solved by a recursive state feedback controller design. Thus our approach applies to a broader class of output regulation problem of MIMO nonlinear systems.