Based on Newton’s second law and the thermal network method,a mechanical thermal coupling model of the bearing rotor system of high-speed trains is established to study the interaction between the bearing vibration a...Based on Newton’s second law and the thermal network method,a mechanical thermal coupling model of the bearing rotor system of high-speed trains is established to study the interaction between the bearing vibration and temperature.The influence of lubrication on the vibration and temperature characteristics of the system is considered in the model,and the real-time relationship between them is built up by using the transient temperature field model.After considering the lubrication,the bearing outer ring vibration acceleration and node temperature considering grease are lower,which shows the necessity of adding the lubrication model.The corresponding experiments for characteristics of vibration and temperature of the model are respectively conducted.In the envelope spectrum obtained from the simulation signal and the experimental signal,the frequency values corresponding to the peaks are close to the theoretical calculation results,and the error is very small.In the three stages of the temperature characteristic experiment,the node temperature change of the simulation model is consistent with the experiment.The good agreement between simulation and experiments proves the effectiveness of the model.By studying the influence of the bearing angular and fault size on the system node temperature,as well as the change law of bearing lubrication characteristics and temperature,it is found that the worse the working condition is,the higher the temperature is.When the ambient temperature is low,the viscosity of grease increases,and the oil film becomes thicker,which increases the sliding probability of the rolling element,thus affecting the normal operation of the bearing,which explains the phenomenon of frequent bearing faults of high-speed trains in the low-temperature area of Northeast China.Further analysis shows that faults often occur in the early stage of train operation in the low-temperature environment.展开更多
针对运营中垃圾填埋场高密度聚乙烯(high density polyethylene,HDPE)膜漏洞修补问题,提出一种将并联机构和热熔焊接加工结合起来的智能焊接机器人系统,围绕机、电、热多能域耦合系统动力学展开研究。利用键合图及旋量键合图理论分别构...针对运营中垃圾填埋场高密度聚乙烯(high density polyethylene,HDPE)膜漏洞修补问题,提出一种将并联机构和热熔焊接加工结合起来的智能焊接机器人系统,围绕机、电、热多能域耦合系统动力学展开研究。利用键合图及旋量键合图理论分别构建了电机驱动子系统、末端热熔焊执行子系统及并联机构机械本体动力学模型,得到机电热多能域系统全解动力学模型。对于给定焊缝实际执行轨迹,通过MATLAB软件状态方程求解、ADAMS软件模型动力学仿真及20-sim键合图仿真综合进行分析验证,验证了该机器人多能域系统动力学全解模型合理性,为其后续动力学参数辨识以及动力学控制研究奠定基础。展开更多
基金supported by the National Key R&D Program of China(No.2020YFB2007700)the National Natural Science Foundation of China(Nos.11790282,12032017,12002221,and 11872256)+1 种基金the S&T Program of Hebei Province of China(No.20310803D)the Natural Science Foundation of Hebei Province of China(No.A2020210028)。
文摘Based on Newton’s second law and the thermal network method,a mechanical thermal coupling model of the bearing rotor system of high-speed trains is established to study the interaction between the bearing vibration and temperature.The influence of lubrication on the vibration and temperature characteristics of the system is considered in the model,and the real-time relationship between them is built up by using the transient temperature field model.After considering the lubrication,the bearing outer ring vibration acceleration and node temperature considering grease are lower,which shows the necessity of adding the lubrication model.The corresponding experiments for characteristics of vibration and temperature of the model are respectively conducted.In the envelope spectrum obtained from the simulation signal and the experimental signal,the frequency values corresponding to the peaks are close to the theoretical calculation results,and the error is very small.In the three stages of the temperature characteristic experiment,the node temperature change of the simulation model is consistent with the experiment.The good agreement between simulation and experiments proves the effectiveness of the model.By studying the influence of the bearing angular and fault size on the system node temperature,as well as the change law of bearing lubrication characteristics and temperature,it is found that the worse the working condition is,the higher the temperature is.When the ambient temperature is low,the viscosity of grease increases,and the oil film becomes thicker,which increases the sliding probability of the rolling element,thus affecting the normal operation of the bearing,which explains the phenomenon of frequent bearing faults of high-speed trains in the low-temperature area of Northeast China.Further analysis shows that faults often occur in the early stage of train operation in the low-temperature environment.
文摘针对运营中垃圾填埋场高密度聚乙烯(high density polyethylene,HDPE)膜漏洞修补问题,提出一种将并联机构和热熔焊接加工结合起来的智能焊接机器人系统,围绕机、电、热多能域耦合系统动力学展开研究。利用键合图及旋量键合图理论分别构建了电机驱动子系统、末端热熔焊执行子系统及并联机构机械本体动力学模型,得到机电热多能域系统全解动力学模型。对于给定焊缝实际执行轨迹,通过MATLAB软件状态方程求解、ADAMS软件模型动力学仿真及20-sim键合图仿真综合进行分析验证,验证了该机器人多能域系统动力学全解模型合理性,为其后续动力学参数辨识以及动力学控制研究奠定基础。
