Motor Condition Monitoring Based On All-fiber Self-mixing Interferometry

Non-destructive testing has the characteristics of non-contact,non-destructive,high precision and high efficiency.It can be well applied to the health monitoring system of motor.In practice,there are many factors leading to motor failure.Only by choosing appropriate non-destructive testing technology according to the characteristics of the fault,can the health status of the specific position of the motor be effectively monitored.This paper focuses on mechanical faults of motors,studies the non-destructive detection technology based on all-fiber self-mixing interference,designs sensors to collect motor vibration signals,proposes a time-domain demodulation technology based on signal orthogonal decomposition,and uses it to collect signals for analysis and processing,real-time reconstruction of motor vibration state.Firstly,the research status and development trend of motor condition monitoring are introduced.Starting from the task of motor condition monitoring,the methods and means of motor condition monitoring are introduced in detail.Various detection methods are compared and analyzed.Laser self-mixing interference vibration measurement technology is mainly studied.Secondly,two main types of motor faults are studied.For the electromagnetic faults of motor,the application principle of stator current detection technology for various kinds of electromagnetic faults is studied.For mechanical faults of motors,the disadvantages of contact sensor in vibration detection technology and the advantages of non-contact self-mixing interference sensor are studied.The theory of self-mixing interference is studied,and its theoretical model is constructed under the condition of all-fiber,and the all-fiber self-mixing interference sensor is designed.A Time Domain Demodulation Technique Based on orthogonal signal decomposition is proposed to process self-mixing signals.This technique can achieve high-precision reconstruction of target object in non-polarization-preserving environment.Finally,in order to verify the feasibility of the theory,a simple motor health monitoring system is designed to verify the applicability of the designed all-fiber self-mixing interferometer sensor,and combine it with the proposed signal processing technology to reconstruct the vibration of the motor under different mechanical faults in real time.The experimental results show that the technology is feasible in motor health monitoring and can provide good technical support for subsequent motor fault diagnosis.