Research ArticleDisturbance observer based fault estimation and dynamic output feedback fault tolerant control for fuzzy systems with local nonlinear models

- In this paper, disturbance observers and the fault estimate observers are designed, and the observers can estimate the system states, disturbances, sensor and actuator faults, simultaneously.
- Compared with the existed results, the proposed observers have a wider application range and more freedom for design. Besides, the time derivative of the output error don't need.
- For fuzzy systems whose measurement output is affected by fault and disturbance, the proposed controller can stabilize the systems with mismatched input disturbance and unmeasurable local nonlinear models.

This paper addresses the problems of fault estimation (FE) and fault tolerant control (FTC) for fuzzy systems with local nonlinear models, external disturbances, sensor and actuator faults, simultaneously. Disturbance observer (DO) and FE observer are designed, simultaneously. Compared with the existing results, the proposed observer is with a wider application range. Using the estimation information, a novel fuzzy dynamic output feedback fault tolerant controller (DOFFTC) is designed. The controller can be used for the fuzzy systems with unmeasurable local nonlinear models, mismatched input disturbances, and measurement output affecting by sensor faults and disturbances. At last, the simulation shows the effectiveness of the proposed methods.