Fuzzy Fault Estimation Observer Design for Head-Two-Arms-Trunk System

This paper presents a observer-based fault estimation strategy for patients with complete spinal cord injury (SCI) that modeled by nonlinear Head-Two-Arms-Trunk (H2AT) system. Due to the complexity of nonlinear H2AT system structure, a Takagi-Sugeno (TS) fuzzy m odel technique is adopted to facility the observer design. However, an undesired unmeasured premise variables are raised which leads to well-known difficulty in designing TS fuzzy observer. To this end, a special fuzzy modeling method named N-TS model is proposed in this paper where the unmeasured nonlinearities are isolated in the local nonlinear consequent. With this model, unmeasurable nonlinear terms are avoid. Moreover, the complexity of the observer structure is reduced which is suit for the practical application. The conditions of designing observer-based fault estimation strategy are given in term of linear matrix inequalities (LMIs) which can be efficiently solved by the existing numerical toolbox. Simulation results presents the effectiveness of the proposed fault estimation method.