Gear assembly errors can lead to the increase of vibration and noise of the system,which affect the stability of system.The influence can be compensated by tooth modification.Firstly,an improved three-dimensional load...Gear assembly errors can lead to the increase of vibration and noise of the system,which affect the stability of system.The influence can be compensated by tooth modification.Firstly,an improved three-dimensional loaded tooth contact analysis(3D-LTCA)method which can consider tooth modification and coupling assembly errors is proposed,and mesh stiffness calculated by proposed method is verified by MASTA software.Secondly,based on neural network,the surrogate model(SM)that maps the relationship between modification parameters and mesh mechanical parameters is established,and its accuracy is verified.Finally,SM is introduced to establish an optimization model with the target of minimizing mesh stiffness variations and obtaining more even load distribution on mesh surface.The results show that even considering training time,the efficiency of gear pair optimization by surrogate model is still much higher than that by LTCA method.After optimization,the mesh stiffness fluctuation of gear pair with coupling assembly error is reduced by 34.10%,and difference in average contact stresses between left and right regions of the mesh surface is reduced by 62.84%.展开更多
针对无线Mesh网络组播中包丢失严重的问题,提出了保持包的IP层不变,而改变包的目的MAC域,进而MAC层以单播形式向组成员发送包的M2U(Multicast to Unicast)优化解决方案.为了满足组成员增加时不影响用户的性能,提出在M2U中引入了机会路由...针对无线Mesh网络组播中包丢失严重的问题,提出了保持包的IP层不变,而改变包的目的MAC域,进而MAC层以单播形式向组成员发送包的M2U(Multicast to Unicast)优化解决方案.为了满足组成员增加时不影响用户的性能,提出在M2U中引入了机会路由的M2UO(Multicast to Unicast Opportunistic Routing)算法,对候选节点采用单播形式发送包,对其它节点采用组播形式发送包.在实际网络环境中的大量实验表明,优化组播减小了数据包的丢失率,提高了网络的吞吐量,具有较好的组播视频流效果.展开更多
基金Project(11972112)supported by the National Natural Science Foundation of ChinaProject(N2103024)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(J2019-IV-0018-0086)supported by the National Science and Technology Major Project,China。
文摘Gear assembly errors can lead to the increase of vibration and noise of the system,which affect the stability of system.The influence can be compensated by tooth modification.Firstly,an improved three-dimensional loaded tooth contact analysis(3D-LTCA)method which can consider tooth modification and coupling assembly errors is proposed,and mesh stiffness calculated by proposed method is verified by MASTA software.Secondly,based on neural network,the surrogate model(SM)that maps the relationship between modification parameters and mesh mechanical parameters is established,and its accuracy is verified.Finally,SM is introduced to establish an optimization model with the target of minimizing mesh stiffness variations and obtaining more even load distribution on mesh surface.The results show that even considering training time,the efficiency of gear pair optimization by surrogate model is still much higher than that by LTCA method.After optimization,the mesh stiffness fluctuation of gear pair with coupling assembly error is reduced by 34.10%,and difference in average contact stresses between left and right regions of the mesh surface is reduced by 62.84%.
文摘针对无线Mesh网络组播中包丢失严重的问题,提出了保持包的IP层不变,而改变包的目的MAC域,进而MAC层以单播形式向组成员发送包的M2U(Multicast to Unicast)优化解决方案.为了满足组成员增加时不影响用户的性能,提出在M2U中引入了机会路由的M2UO(Multicast to Unicast Opportunistic Routing)算法,对候选节点采用单播形式发送包,对其它节点采用组播形式发送包.在实际网络环境中的大量实验表明,优化组播减小了数据包的丢失率,提高了网络的吞吐量,具有较好的组播视频流效果.
