Research On 2-DOF Parallel Adjustment Platform Based On The Four-bar Tensegrity Structure

Parallel mechanism has been widely studied and applied in the field of intelligent manufacturing and robot industry.Its advantages such as small cumulative motion error,high precision,high load bearing and small motion inertia can be applied to different working environments.In recent years,the research on the parallel mechanism is gradually mature.In order to meet the development needs of the parallel mechanism,the characteristics of the tensegrity structure bring new inspiration and ideas to the parallel mechanism,and the tensegrity structure is applied to the parallel mechanism,and a new mechanism is obtained: the tensegrity parallel mechanism.The new mechanism not only retains the advantages of parallel mechanism,but also has the characteristics of light weight,easy deformation,impact resistance,self-balance and self-stability of tensegrity structure.The tension integral structure is composed of a number of tension rods and compression cables.The tension rods provide tension in the structure and the compression cables provide tension in the structure.It is a stable spatial structure with self-balance of internal stress.Based on the parallel mechanism and the tensegrity structure,this paper designs the mechanism configuration of the four-bar tensegrity structure with two degrees of freedom parallel adjustment platform.It has the advantages of both structures at the same time,and can automatically and stably restore to the initial position after the drive.Firstly,design of parallel platform mechanism based on tensegrity structure.The node matrix of tensegrity structure was established by the coordinate system,and its trajectory law was expressed.Then,the angular Angle α of the four-bar tensegrity structure was obtained,and the mechanism configuration was determined.The two degrees of freedom can be reversed by limiting the freedom of the moving pair,and the self-balance and self-stability of the tensioning structure can be played.Secondly,the kinematic solution and singularity analysis of the four-bar tensioned integral parallel mechanism are presented.The kinematics solution of parallel mechanism is mainly to study the relationship between input parameters and output parameters by means of coordinate change and rotation matrix.In addition,when the mechanism moves to the singularity point,the mechanism will lose or gain the degree of freedom,and then the mechanism will become unstable,which can be avoided by analyzing it.Then,the workspace and simulation of the four-bar tensioned integral parallel mechanism are solved.By solving the space of the parallel mechanism,a larger working space can be achieved and the kinematic performance of the mechanism can be improved.At the same time,the parallel mechanism is simulated by simulation software,and the simulation data of the mechanism in the process of motion is obtained,which is compared with the theoretical data mentioned above to prove the rationality of the mechanism.Finally,the physical prototype is made and tested.Through the selection of standard room,processing and assembly of non-standard parts,prototype production.The driving force measurement experiment of the prototype proves that the prototype has the flexibility and can give full play to the advantages of self-balance and self-stability of the tensioning integral structure.The centering experiment of the physical prototype proves that the actual turnover is basically consistent with the theoretical calculation,which proves the practical feasibility and structural rationality of the prototype.