A Short-wave Irregularity Measurement Device Based on Optimal Configuration and Area Parameter Inversion Model

Introduction: Rail short-wave irregularity critically impacts train safety and ride quality by inducing excessive vibration and noise. Aiming at system instability and error accumulation caused by the Multipoint Chord Reference (MCR) system during the inversion process, an area parameter inversion method is proposed to correct errors. Furthermore, a dynamic measurement device is designed to ensure the reliability of the measurement result. Methods: The inversion model is established using the area parameter calculation method, and an improved Levenberg-Marquardt algorithm is employed to enhance the computational efficiency of waveform reconstruction. The model is validated through multiple stochastic simulations, and the optimal configuration is assessed via comparative analysis. Based on the optimal configuration and relevant patents, a measuring device has been developed that integrates four laser displacement sensors with a 3D profile scanner. The proposed method has been applied in field tests. Results: Simulation results show that the area parameter inversion model meets the requirements for high-precision restoration, the error is controlled at 5 μm. The optimal configuration is determined to be L = 300 mm and N = 5. The measured wavelengths in the field test are all less than 200 mm. The peak value of the amplitude-frequency response curve is 0.81 mm, with the corresponding main wavelength of 116 mm. The amplitude information is obtained through filtering, which is in line with the actual working conditions. Discussion: The response change of the area parameter inversion model to the rail irregularity in different wavelength segments is evaluated in terms of transfer function and power spectral density. In the unmeasurable wavelength range, the characteristics of the inversion waveform show fluctuations. According to the test results, under the optimal configuration, the area parameter inversion method can achieve high-precision short-wave irregularity restoration while maximizing the measurable wavelength range. Conclusion: The result confirms that the area parameter inversion model integrated into the measurement device can accurately invert the waveform while significantly capturing wavelength information. Future work will improve the performance in terms of device configuration and multiwaveform measurement.