Abstract:Aiming at the demand of autonomous positioning of rail construction vehicles， this paper proposes a method of absolute position extraction of rail vehicles based on the video of 100-metre markers captured by the on-board forward-looking camera. The method first improves the YOLOX-s network and constructs the target detection model of the 100-metre marker to complete the target detection of the 100-metre marker. Then， when the 100-metre marker is detected， it combines image preprocessing with convolutional recurrent neural network （CRNN） network to construct the 100-metre marker digital text recognition model to extract the digital text information of the 100-metre marker， so as to achieve the absolute position location of rail construction vehicles. The method is verified to be able to quickly and accurately extract the absolute position information of rail construction vehicles.

Abstract:A theoretical model of steady-state curve negotiation of coupled bogie for straddling monorail vehicle was established, the mechanism of radial adjustment of the coupled bogies was analyzed, and the formula for calculating the coupling parameters required for achieving the radial state was derived. The dynamics model of straddling monorail vehicle equipped with coupled bogies was established, and the curving performance of the coupling bogie was simulated, and the radial adjustment capacity of coupled bogie was verified. Meanwhile, the influence of coupling parameters on the radial adjustment capacity and curving performance of the coupled bogie was also analyzed. The results show that the optimal rotary stiffness is only related to the vehicle structural parameters and the secondary longitudinal stiffness. The reasonable selection of the coupling rotary stiffness can make the coupling bogie automatically reach the radial position on the circular curve under the joint action of the secondary suspension system and the coupling mechanism. At this time, the maximum radial force of guiding wheels is obviously reduced, and the curve passing safety of the vehicle is significantly improved. The coupling lateral stiffness has little effect on the steady value of the yaw angle of the coupled bogie, but it will worsen the dynamic performance of the bogie on the transition curve.

Abstract:Aimed at the characteristics of complex vibration environment when estimating the fatigue life of rail vehicle equipment, an inductive method of random vibration environment suitable for rail vehicle equipment is proposed, and a fatigue life estimation process of rail vehicle equipment is solved based on the inductive method. Combining the vibration environment data in the parameter hypothesis test, the upper tolerance limit of the sample is estimated, and the measured spectrum and the normalized spectrum are obtained. Taking the fatigue fracture of the axle box lug of a certain type of subway vehicle as an example, the measured stress is statistically analyzed, and the measured spectrum and the normalized spectrum are used as excitation to simulate the fatigue life of the lug. The results show that compared with the fatigue result at the measured stress, the relative errors of the simulation results of the measured spectrum and the normalized spectrum are 1.8% and 4.1%, respectively, which proves that the proposed vibration environment inductive method and the fatigue life estimation method are highly reliable and can provide references for practical engineering applications.

Abstract:The measured acceleration data of vibration in rail vehicles show strong non-normality, and Johnson’s law is used to improve the criterion of inducing vibration data. A universal induction method of vibration spectrum is proposed in this paper. By using the measured data, the difference between the ordinary method and the modified method is compared, and the universality of the method is tested. The results show that the modified method can adapt to the non-normal environment and the induced spectrum can reflect the actual vibration.