Abstract：To overcome the computation singularity that the traditional computing order tracking (COT) is not able to estimate the re-sampling time when the rotor system rotates with an invariable frequency or slow-variable frequency, an improved COT method is proposed on the basis of the cubic spline interpolation. Since the cumulate rotation angular increases monotonically as the time pass-by, the time variable is presented to be the function of the cumulate rotation angular based on the principle that the inverse function of a monotone function inevitably exists. The cubic spline interpolation method is used to solve the equations and obtains the re-sampling time of the arbitrary rotation condition. Simulation and experiment are used to validate the efficacy of the improved COT method at various rotation conditions. By solving the computation singularity of the traditional COT method in the application of the invariable or slow-variable rotation frequency condition, the improved COT method extends the applicable range of the COT method and is valuable in engineering applications.
2015, Vol. 34 
