The Fault Diagnosis Of Linear Switched Systems Based On Sliding Mode Observer

With more and more complex systems which have been used in practicalengineering, the fault diagnosis technology has become a hot research direction.As an important type of hybrid system, switched systems have its practicalsignificance for the engineering. So an increasing number of hybrid systems havebeen applied in the reality, such as automobile engine control, robot control, etc.However, precise mathematical model is, sometimes, difficult to be built anduncertainty and nonlinear disturbance is widespread in the actual systems. So ithas become a hot topic that how to effective control systems with uncertainty anddisturbance. The sliding mode control has good robustness to generic system andhas perfect robustness to uncertainty that satisfied the matching condition,because its sliding mode is insensitivity to the external disturbance and parameterperturbation. Therefore, the idea has received the widespread attention thatsliding mode controller is applied to control the switching system.In this work, the actuator and sensor fault diagnosis is studied respectively,combined sliding-mode control theory with the fault diagnosis method based onobserver so that it is proposed that actuator and sensor fault diagnosis algorithmsbased on the sliding mode observer for a class of linear switched systems withnonlinear perturbations.As the fault diagnosis algorithms generalized, the faultdiagnosis algorithm with concurrent fault of actuator and sensor for a class ofuncertain time-delay switched systems with nonlinear disturbance.At last, itsfeasibility is to verify by simulation.Firstly, the related theory of switched systems and fault diagnosis areintroduced. It includes theoretical knowledge of switch system, asymptoticstability theorem and the three methods of fault diagnosis are expounded.Secondly, a sliding mode observer design algorithm is proposed for a classof linear switched systems with nonlinear disturbance. The basic knowledge of the sliding mode control, and design method of sliding mode controller isintroduced in detail; On that basis, sliding mode observer is designed for a classof linear switched systems with nonlinear perturbations： Combined multiplelyapunov function method with LMI, a sufficient condition is obtained to makethe linear switched system asymptotic stability and proved to meet the conditionsof sliding mode control, the sliding mode surface is accessible. At last, itsfeasibility is to verify by simulation.Next, based on sliding mode observer method, diagnosis algorithms ofactuator and sensor fault is, respectively, proposed for a class of linear switchedsystems with nonlinear perturbation. The mathematical model is given for thissystem with actuator and sensor fault.Based on the sliding mode observer design algorithm, actuator and sensorfault diagnosis to be researched for this switched system, so that the actuator andsensor fault diagnosis algorithms based on sliding mode observer is obtained. Atlast, its feasibility is to verify by simulation.As the fault diagnosis algorithms generalized, the fault diagnosis algorithmwith concurrent fault of actuator and sensor for a class of uncertain time-delayswitched systems with nonlinear disturbance. At last, its feasibility is to verify bysimulation.