Research On Fault Detection Method Of Linear Switched System Under Relaxed Persistent Dwell Time Constraint

Fault detection has become an in-depth research topic due to the growing demand for safety and reliability.On the other hand,many practical systems are multimodal and can be modeled with switched systems.In recent years,switching systems have been widely used in aerospace,biological fields,and mechanical systems.It is worth pointing out that good fault-sensitivity performance and disturbance rejection performance are the prerequisites for fault detection.However,the switching rules will have a great impact on the performance of systems,which makes the fault detection problem of switching systems more difficult to deal with.Based on the relaxed persistent dwell time switching,this paper studies the fault detection of linear switched systems.The main research contents of this paper are as follows:(1)The design of fault filters for discrete switched systems with relaxed persistent dwell time is studied.The switching rule is constructed based on persistent dwell time(PDT)with an average dwell time(ADT)constraint.The introduced ADT constraint can allow a much smaller PDT lower bound to be designed,which further improves the flexibility of the switching signal design.Furthermore,we design a suitable fault detector,and verify the feasibility of the proposed results through simulation experiments.(2)The problem of simultaneous control and fault detection for discrete switched systems with relaxed persistent dwell time is studied.Under relaxed persistent dwell time switching,in order to achieve the control and detection objectives at the same time,we design a time-varying dynamic output feedback controller/fault detector matching the switching process.Compared with the existing time invariant controller/fault detector,our proposed results have less conservatism and better effect.Finally,the effectiveness of the proposed results is illustrated by an example.(3)The problem of simultaneous control and fault detection(FD)for discrete-time switched systems with relaxed persistent dwell time regularity is studied.When the switched systems are with partial measurable states,we directly use these states to construct partial control and FD signals.Next,the reduced-order control/detection unit(CDU)is designed to generate the other control and FD signals.Compared with existing results based on full-order CDU,the proposed results lead to less conservatism and reduce design complexity.The switching law is constructed in the frame of persistent dwell time(PDT)switching.A novel switching number constraint condition is introduced,which further relaxes the restrictions on the dwell time of switching processes of PDT.The less restriction on dwell time upgrades the degree of freedom for switching law design.Based on the proposed results,a class of non-weighted performance indexes is introduced to characterize the fault sensitivity and robustness.The effectiveness of the proposed method is illustrated by an example.Finally,the research is summarized,and the development trend of this subject is prospected.