Adaptive fuzzy control for multi-input multi-output nonlinear systems with unknown dead-zone inputs

•The adaptive fuzzy control is proposed for MIMO nonlinear systems with unknown dead-zone inputs.•The symmetric matrix decomposition technique is used to design the controller.•The controller is developed to avoid the possible controller singularity problem.•The controller is developed to avoid the parameter initialization condition constraints problem.•The well-defined dynamic robust controller is employed to compensate for the lumped errors.

This paper presents an adaptive fuzzy control scheme for a class of uncertain multi-input multi-output (MIMO) nonlinear systems with the nonsymmetric control gain matrix and the unknown dead-zone inputs. In this scheme, fuzzy systems are used to approximate the unknown nonlinear functions and the estimated symmetric gain matrix is decomposed into a product of one diagonal matrix and two orthogonal matrices. Based on the decomposition results, a controller is developed, therefore, the possible controller singularity problem and the parameter initialization condition constraints problem are avoided. In addition, a dynamic robust controller is employed to compensate for the lumped errors. It is proved that all the signals in the proposed closed-loop system are bounded and that the tracking errors converge asymptotically to zero. A simulation example is used to demonstrate the effectiveness of the proposed scheme.

Graphical abstractOverall scheme of the adaptive fuzzy control. Figure optionsDownload full-size imageDownload as PowerPoint slide