Research On Assembly Technology Of Space Vertical Truss Based On Manipulator

The space vertical truss will play an important role in the on-orbit construction of the space station carrying platform in the future due to its strong functionality,expandability and easy maintenance.Based on the space pre-research project and aiming at the on-orbit assembly of large space vertical trusses,this thesis proposes an assembly strategy of trusses based on manipulator and carries out ground assembly verification tests.The main research contents of this thesis are as follows:According to the special assembly scene and structural characteristics of space vertical trusses,modular assembly is introduced to decompose the assembly task of truss unit group into two parts,extravehicular assembly connecting strut and intracavitary assembly preassembly module.The assembly sequence planning of truss elements is realized by establishing a priority constraint relation classification model.A spherical node expression model is established by using a two-dimensional matrix,and the rationality of the truss unit assembly process is verified in the simulation environment DELMIA.In view of the installation of connecting struts outside the cabin,this thesis proposes to measure the target pose of the struts by detecting and identifying marks through the end camera on the basis of considering the structural size characteristics of the struts.According to the connection characteristics of the struts,a marking placement strategy is formulated and the pose conversion relation between the struts and the manipulator is determined.In order to ensure the success of assembly when manipulator grasping the strut,the motion planning of the manipulator was studied in the operating space and the feasibility of the planning method was verified by design experiments.In view of the installation of pre-assembled module struts in the cabin,this thesis proposes an assembly method of dual-arm compliant based on force sensor.Firstly,by analyzing the unique structural characteristics and matching process,the matching results are divided into four types of working conditions and the mechanical models of various states under each working condition are established.Secondly,through the feedback information of the force sensor,the matching state of the strut is judged,so that the corresponding robot end pose adjustment strategy is formulated.Finally,the effectiveness of the compliant assembly strategy is verified by building a dual-arm compliant assembly platform and analyzing the force and moment data under various working conditions obtained in the test.