The expressions for nucleation rate in metallic melt on the ground and under elevated gravity have been derived theoretically and the effects of gravity and elevated gravity on nucleation rate have been discussed. A c...The expressions for nucleation rate in metallic melt on the ground and under elevated gravity have been derived theoretically and the effects of gravity and elevated gravity on nucleation rate have been discussed. A comparison of nucleation rate under microgravity with those on the ground and under elevated gravity has also been made展开更多
To eliminate the load weight limit of carrier rockets and reduce the burden on support structures,in-orbit assembly is a key technology to make design of scattering a large diameter telescope into submirror modules,wh...To eliminate the load weight limit of carrier rockets and reduce the burden on support structures,in-orbit assembly is a key technology to make design of scattering a large diameter telescope into submirror modules,which requires smooth operation of assembly robots,and flexible force control technology is necessary. A ground demonstration system is presented for in-orbit assembly focusing on flexible force control. A six-dimensional force/torque sensor and its data acquisition system are used to compensate for gravity. For translation and rotation,an algorithm for flexible control is proposed. A ground transportation demonstration verifies accuracy and smoothness of flexible force control,and the transportation and assembly task is completed automatically. The proposed system is suitable for the development of in-orbit assembly robots.展开更多
文摘The expressions for nucleation rate in metallic melt on the ground and under elevated gravity have been derived theoretically and the effects of gravity and elevated gravity on nucleation rate have been discussed. A comparison of nucleation rate under microgravity with those on the ground and under elevated gravity has also been made
基金Supported by the National Natural Science Foundation of China(No.11672290)
文摘To eliminate the load weight limit of carrier rockets and reduce the burden on support structures,in-orbit assembly is a key technology to make design of scattering a large diameter telescope into submirror modules,which requires smooth operation of assembly robots,and flexible force control technology is necessary. A ground demonstration system is presented for in-orbit assembly focusing on flexible force control. A six-dimensional force/torque sensor and its data acquisition system are used to compensate for gravity. For translation and rotation,an algorithm for flexible control is proposed. A ground transportation demonstration verifies accuracy and smoothness of flexible force control,and the transportation and assembly task is completed automatically. The proposed system is suitable for the development of in-orbit assembly robots.
