Research On Active Fault-tolerant Control Of Stiffened Plate Vibration

With the improvement of the performance requirements of materials in the industrial field,the application of stiffened plate structure with high strength and strong durability is becoming more and more extensive.However,when the stiffened plate structure is disturbed by external forces,it will produce vibration and bring a series of adverse effects,so it is necessary to control its vibration.At present,the conventional vibration control system of stiffened plate takes a long time to enter the steady state and has obvious chattering phenomenon.In addition,the piezoelectric sensor used to measure vibration in the control system is prone to failure,which will directly affect the control effect and even lead to control failure.Aiming at the above problems,this paper takes the stiffened plate as the research object,and uses the sliding mode variable structure control based on the improved approach law to control its vibration.Then,the multi-feature fusion and improved SVM method are used for fault diagnosis of piezoelectric sensor.Finally,the corresponding fault-tolerant control strategy is developed,and the vibration fault-tolerant control system based on the observer is designed to realize the vibration control of the stiffened plate under the failure of the sensor.The main contents of the paper are as follows:Firstly,based on the characteristics of piezoelectric materials,the dynamic model of the vibration system of the piezoelectric stiffened plate is established,and the modal analysis of the 3D model of the stiffened plate and the built stiffened plate is carried out by means of finite element analysis and frequency sweep experiment,and the modal parameters and modal response positions of each order are obtained.Secondly,the traditional approach law of sliding mode variable structure control is improved and its convergence is proved.The simulation system of vibration control of stiffened plate is designed.The experimental results show that the vibration control effect can reach 51.4%,which is better than the traditional unimproved approach rate algorithm.Then,aiming at the common break and degumming faults of piezoelectric sensor in vibration control system,the SVD value and Hilbert marginal spectrum features of multiple vibration response signals are extracted by experiments,and the improved SVM method is used to identify the faults of SVD value,Hilbert marginal spectrum features and fusion features respectively.The results show that the accuracy of fault identification under the fusion features can reach 95%.At the same time,the experimental results show that the fault recognition effect of the fusion feature is better than that of the single feature.Finally,the vibration fault-tolerant control strategy under the fault of piezoelectric sensor is formulated,and the observer based vibration fault-tolerant control system of stiffened plate is designed.The fault equation is observed in combination with the system input,then the normal signal is estimated,and then the vibration of stiffened plate is controlled by the improved sliding mode control algorithm.The simulation system is designed to verify its feasibility,and a fault-tolerant vibration control experimental platform is built for the experiment.The experimental results show that 51.3%of the vibration control effect is achieved under the fault of piezoelectric sensor,and the fault-tolerant control of stiffened plate vibration under the fault of sensor is realized.Figure[72]table[8]reference[85]...