Research On The Torsional Vibration Testing System Of Shafting Based On Fiber Optic Sensing Technology

Rotating machinery is playing an increasingly important role in modern industry.With the increasing demand for performance,rotating machinery is moving towards large scale,high speed and high load,which makes rotor systems more susceptible to torsional vibration.Torsional vibration can disrupt the smooth operation of mechanical equipment and cause serious consequences,so it is necessary to monitor torsional vibration,in which it is crucial to analyze and compensate for the measurement error of torsional vibration.This paper researches the torsional vibration measurement system based on fiber optic sensing,analyzes various error factors that may be encountered in the process of measuring torsional vibration in this torsional vibration measurement system,and gives the corresponding error compensation scheme,and verifies the effectiveness of each error compensation scheme through simulation model and experiment.The main research content of this paper includes:This thesis first briefly introduces the measurement principle of torsional vibration measurement system and the analysis method of torsional vibration signal.The development history of torsional vibration measurement methods is described and the advantages and disadvantages of various torsional vibration measurement methods are compared.The principles,advantages and disadvantages of various error compensation schemes are analyzed.The torsional vibration measurement method based on stripe width was studied from both simulation and experimental dimensions.The influence of system noise error,data acquisition error,bending vibration error,and stripe width error on torsional vibration measurement was analyzed through simulation model.Simulation results show that the influence of system noise error can be effectively eliminated by filtering pseudo-pulse periods;the sampling rate and streak indexing number should be chosen to match each other to ensure a low error level without wasting resources;the normalization of pulse signal can effectively eliminate the influence of parallel component of bending vibration,and the 180° symmetrical arrangement of double probes can eliminate the influence of vertical component of bending vibration;the method of simultaneous average compensation of pulse periods can effectively weaken the influence of streak width error,but it is not applicable when the frequency of torsional vibration coincides with the frequency of speed multiplier.Then we built a torsional vibration test system and experimentally validated various error compensation schemes to verify the feasibility of the measurement method.In view of the limitations of the stripe width-based torsional vibration measurement method,we propose two solutions: one is to use the reflected light intensity to calibrate the width of the white stripe,and then use the calibrated white stripe width for torsional vibration measurement,and the feasibility of this scheme is verified through the finite element simulation model,and the simulation results show that: the relationship between the reflected light intensity and the white stripe width can be established,and the white stripe width can be calibrated through the reflected light intensity;the second is to propose a structured light-based torsional vibration measurement method,which is validated by simulation and experiment.The results show that the structured light-based torsional vibration measurement method avoids the effect of streak width error and also avoids the problem that the rising edge duration of a single spot is difficult to extract accurately,which providing a new idea for torsional vibration measurement.