The Active Minor Fault Detection Based On Auxiliary Input Signal Design And Controller Reconfiguration

The minor faults are generally the precursors of significant faults.The more accurate the micro fault detection is,the more conducive to the safe operation of the system.Due to the inherent fault tolerance of the traditional controller,it is difficult to detect the initial minor faults,but such failures should be eliminated as soon as possible because the minor faults become more pronounced over time.As the existing detection method is generally based on the passive methods,this paper has carried on active fault detection mechanism and do some research and exploration on the minor faults detection and tolerant control.This paper proposes two solutions for minimal parameter fault detection problem of linear steady system.Firstly,the paper proposes an active fault detection method which is based on controller reconfiguration.Active fault detector(AFD)and partial active fault tolerant controller(PAFTC)are constructed respectively by analyzing the relationship between minor faults and double Youla-Jabr-Bongiorno-Kucera(YJBK)parameters.And we propose an unified framework for AFD and PFTC,so that the AFD module has been running when system is stable,and there is no influences on the output.When the fault occurs,the system will automatically switch to the FTC subsystem to protect the system further.The decision signal of the AFD method based on the controller reconfiguration is that the system output or residual exceeds the threshold,which makes the system appear transient instability,so the design of the tolerant controller is significant and urgency.In order to simplify the system structure,a new fault detection method based on auxiliary input signal design is proposed under the same YJKB parameterization framework.The reason is explained why the selected design signal is sinusoidal signal by analyzing the relationship between fault feature matrix and frequency.Then,according to the design requirements,the fault evaluation index is given which can guarantee the rapid active detection and system stability of the small fault at the same time,and we use the multi-objective optimization method to find the appropriate frequency and amplitude of the auxiliary signal.Finally,the simulation results of the above two kinds of different fault detection methods are tested to verify the micro fault detection capability.