Nonlinear disturbance observer-based control for multi-input multi-output nonlinear systems subject to mismatching condition

• Published in: International journal of control Vol. 85; no. 8; pp. 1071 - 1082
• Main Authors: Yang, Jun, Li, Shihua, Chen, Wen-Hua
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis Group 01.08.2012; Taylor & Francis; Taylor & Francis Ltd
• Subjects: Applied sciences; arbitrary disturbance relative degree; Attenuation; Channels; Computer science; control theory; systems; Control systems; Control theory. Systems; disturbance attenuation; Disturbances; Dynamical systems; Exact sciences and technology; Mathematical models; mismatching condition; Modelling and identification; multi-input multi-output nonlinear system; nonlinear disturbance observer; Nonlinear dynamics; Nonlinear systems; Nonlinearity; Studies; MIMO system; arbitrary disturbance relative degree; multi-input multi-output nonlinear system; Disturbance rejection; Non linear control; nonlinear disturbance observer; Feasibility; disturbance attenuation; System identification; Non linear system; Non linear observer; mismatching condition
• ISSN: 0020-7179; 1366-5820; 1366-5820
• DOI: 10.1080/00207179.2012.675520

For a multi-input multi-output (MIMO) nonlinear system, the existing disturbance observer-based control (DOBC) only provides solutions to those whose disturbance relative degree (DRD) is higher than or equal to its input relative degree. By designing a novel disturbance compensation gain matrix, a generalised nonlinear DOBC method is proposed in this article to solve the disturbance attenuation problem of the MIMO nonlinear system with arbitrary DRD. It is shown that the disturbances are able to be removed from the output channels by the proposed method with appropriately chosen control parameters. The property of nominal performance recovery, which is the major merit of the DOBCs, is retained with the proposed method. The feasibility and effectiveness of the proposed method are demonstrated by simulation studies of both the numerical and application examples.