Research On Track Irregularity And Vehicle Dynamic Performance Of Straddle Monorail

With the rapid development of urbanization,people’s demand for convenient and efficient urban transportation system is increasing.In recent years,the straddle type monorail system has attracted the attention and research of many countries because of its strong line adaptability,low comprehensive cost,convenient subsequent route change and other advantages.In the running process of straddle type monorail vehicle,the track beam surface irregularity is one of the important incentives to cause vehicle vibration,which is closely related to vehicle running stability and safety.In this paper,the research status of track beam irregularity detection technology is summarized,and the research content and status of straddle type monorail vehicle dynamics are described in detail.The advantages and disadvantages of chord measurement method,inertial reference method,fixed reference method and other irregularity detection principles are analyzed,and the fixed reference method is selected to develop the irregularity detection system for the track beam surface.Firstly,the main structure of the instrument is designed according to the detection principle,including the reference rod part,the sensor bracket part and the stabilizer rod part;Secondly,based on Arduino MCU platform,the program of irregularity measurement and control system is designed and developed,which is mainly divided into two modules: data acquisition part and motor control part;Finally,the upper computer operation interface program is written based on Python language to realize the functions of reading,storage and visualization of irregularity data.The track beam irregularity of Xishui straddle monorail line is tested,and the actual irregularity spectrum is obtained after data preprocessing.The results show that the measured irregularity is mainly short wave,the wavelength is mainly concentrated in the range of 0-3m,and the power spectrum is between class a pavement and class B pavement.At the same time,the vehicle dynamics test was carried out,and the vibration acceleration data of corresponding measuring points were collected for comparative study.In this paper,the overall structure of Xishui straddle type monorail vehicle and the stress situation of the vehicle in all directions are sorted out,the topological structure diagram of the model is drawn,and the vehicle dynamic model is established.The measured irregularity data is used as the excitation input model for simulation calculation,and the simulation results are compared with the measured data.The results show that the dominant frequency of bogie lateral vibration is about 45 Hz,the dominant frequency of vertical vibration is 5-10 Hz,and the dominant frequency of car body lateral and vertical vibration is within 5Hz;The maximum deviation of the dynamic performance index between the simulation and the measured data is17.5%,and the minimum deviation is 1.2%,which proves that the measurement accuracy of the irregularity detection system is good,and it can restore the real situation of the surface irregularity of the straddle track beam.Based on the dynamic simulation model of monorail vehicle,the effects of irregularity excitation,radial stiffness of running tire and vertical stiffness of secondary hourglass spring on vehicle dynamic performance are studied.The simulation results show that the measured irregularity of the track beam is between the national grade a pavement and grade B pavement;At the same time,according to the simulation results,the change trend caused by each influencing factor is obtained,and the reasonable range of each influencing factor is given.The research results of this paper provide a certain reference value for the irregularity detection of straddle track beam,and have a positive significance for the study of dynamic performance of monorail vehicles.