仿真（simulation）是一种模拟工具，可以方便地解析复杂的技术现象，是现代科研咨询工作中的重要工具。近几年来，欧美开发的MBD（Mult Body Dynamics）仿真系统，能很容易地解析复杂的机械运动。日本铁道综合技术研究所将其应用到刚...仿真（simulation）是一种模拟工具，可以方便地解析复杂的技术现象，是现代科研咨询工作中的重要工具。近几年来，欧美开发的MBD（Mult Body Dynamics）仿真系统，能很容易地解析复杂的机械运动。日本铁道综合技术研究所将其应用到刚体和弹性运动的仿真与机构解析，成为多用途列车运动解析技术或称仿真技术。展开更多
In order to simulate the gait of human walking on different terrains a new robot with six degrees of freedom was proposed. Based on sand bearing characteristic compliance control was introduced to control system in ho...In order to simulate the gait of human walking on different terrains a new robot with six degrees of freedom was proposed. Based on sand bearing characteristic compliance control was introduced to control system in horizontal and vertical movement directions at the end of the robot,and position control in attitude. With Matlab/Simulink toolbox,the system control models were established,and the bearing characteristics of rigid ground,hard sand,soft sand and softer sand were simulated. The results show that 0,0.62,0.89 and 1.12 mm are the maximal subsidences of the four kinds of ground along the positive direction of x-axis,respectively,and 0,-0.96,-1.99 and -3.00 mm are the maximal subsidences along the negative direction of x-axis,respectively. Every subsidence along y-axis is negative,and 0,-4.12,-8.23 and -12.01 mm are the maximal subsidences of the four kinds of ground,respectively. Simulation results show that the subsidence of footboard points to inferior anterior in early stage of stand phase,while points to posterior aspect in late stage. The subsidence tends to point to posterior aspect in the whole. These results are basically consistent with the gait characteristics of human walking on sand. Gait simulation of the robot for human walking on sand is achieved.展开更多
The hydrodynamic problem of a two-dimensional model of seafloor mining tool entering still water vertically at constant speed was analyzed based on the velocity potential theory. For the assumption that the water entr...The hydrodynamic problem of a two-dimensional model of seafloor mining tool entering still water vertically at constant speed was analyzed based on the velocity potential theory. For the assumption that the water entry occurs with very short time interval, the viscosity and gravity of fluid were neglected. Considering the characteristic shape of it, the seafloor mining tool was simplified as a flat-bottom body. The governing equations were the Reynolds time-averaged equations and the k-e model. Finite element analysis was undertaken using the CFD software, Fluent. The impact pressures on the bottom of the mining tool were computed based on the improved volume of fuid method （VOF）. The pressure distribution, the maximum impact pressure, and the impact duration time during the water entry of mining tool are presented at various deploying velocities, the two peak pressures in the impact process are observed, and the relationship between the maximum impact pressure and the deploying velocity is obtained. The results are compared with those based on other prediction theories and methods.展开更多
文摘仿真（simulation）是一种模拟工具，可以方便地解析复杂的技术现象，是现代科研咨询工作中的重要工具。近几年来，欧美开发的MBD（Mult Body Dynamics）仿真系统，能很容易地解析复杂的机械运动。日本铁道综合技术研究所将其应用到刚体和弹性运动的仿真与机构解析，成为多用途列车运动解析技术或称仿真技术。
基金Project(60575053) supported by the National Natural Science Foundation of China
文摘In order to simulate the gait of human walking on different terrains a new robot with six degrees of freedom was proposed. Based on sand bearing characteristic compliance control was introduced to control system in horizontal and vertical movement directions at the end of the robot,and position control in attitude. With Matlab/Simulink toolbox,the system control models were established,and the bearing characteristics of rigid ground,hard sand,soft sand and softer sand were simulated. The results show that 0,0.62,0.89 and 1.12 mm are the maximal subsidences of the four kinds of ground along the positive direction of x-axis,respectively,and 0,-0.96,-1.99 and -3.00 mm are the maximal subsidences along the negative direction of x-axis,respectively. Every subsidence along y-axis is negative,and 0,-4.12,-8.23 and -12.01 mm are the maximal subsidences of the four kinds of ground,respectively. Simulation results show that the subsidence of footboard points to inferior anterior in early stage of stand phase,while points to posterior aspect in late stage. The subsidence tends to point to posterior aspect in the whole. These results are basically consistent with the gait characteristics of human walking on sand. Gait simulation of the robot for human walking on sand is achieved.
基金Project(2006AA09Z240) supported by the National High Technology Research and Development Program of China Project(DYXM 115-04-02-01) supported by the National Deep-Sea Technology Program of Development and Research of the Eleventh Five-year Plan of China
文摘The hydrodynamic problem of a two-dimensional model of seafloor mining tool entering still water vertically at constant speed was analyzed based on the velocity potential theory. For the assumption that the water entry occurs with very short time interval, the viscosity and gravity of fluid were neglected. Considering the characteristic shape of it, the seafloor mining tool was simplified as a flat-bottom body. The governing equations were the Reynolds time-averaged equations and the k-e model. Finite element analysis was undertaken using the CFD software, Fluent. The impact pressures on the bottom of the mining tool were computed based on the improved volume of fuid method （VOF）. The pressure distribution, the maximum impact pressure, and the impact duration time during the water entry of mining tool are presented at various deploying velocities, the two peak pressures in the impact process are observed, and the relationship between the maximum impact pressure and the deploying velocity is obtained. The results are compared with those based on other prediction theories and methods.
