ACTIVE-CONTROL-ORIENTED DYNAMIC MODELLING FOR ON-ORBIT ASSEMBLY SPACE STRUCTURE

Subject to carrying capacity of a launch vehicle, on-orbit assembly technology has become one of the most promising solutions for building ultra-large space structures in the future. The size of the space structure is gradually increasing, and the dynamic characteristics are changing during the assembly process, which brings new challenge to the dynamic modelling and structural active control. Aiming at this issue, an active-control-oriented dynamic modelling method for the on-orbit assembly space structure is proposed in this paper. As the on-orbit assembly mission possess high regularity and repeatability, the basic model database is firstly established for different modules to improve the modelling efficiency, including the module type, the assembly interface, etc. In order to describe the varying on-orbit assembly space structure, the adjacent matrices of modules are defined. The form of intelligent component (IC) oriented to distributed control are then designed, taking the characteristics of the assembly task into consideration. Based upon the finite element modelling method, the 'node freedom degree loading' method is proposed to develop the dynamic models of the IC and the whole space structure, which are adaptively updated along with assembly. Finally, the numerical simulation are carried out on the truss structure under the assembly impact, including the dynamics analysis and the distributed vibration control. The simulation results show that the dynamic characteristics of truss structure experience obvious changes during the process, and the active vibration control is necessary; the modelling method proposed in this paper, with the established basic model database and the 'node freedom degree loading', applies to various on-orbit assembly space structure; According to the adjacency relation matrix, the active-control-oriented dynamic models of the IC can be updated in a limited range during the assembly process, which reduces the complexity of control system and is suitable for distributed active control of on-orbit assembly structure.