Research On Mechanism And Performance Of Four-Dof Parallel Robot

Comparison of 6-DOF parallel robot, the space less degrees of freedom parallel robot has much characteristic that is the structure simple, less components, design and manufacture simple, less cost, becoming a hot topic in robot research in recent years, with more of high research value and broad application prospects. The researches of two and three degrees of freedom parallel mechanism have been mature. There are some researches for symmetrical four and five degrees of freedom parallel mechanism with symmetrical structure, identical branch and isotropic. But for non-symmetric four and five degrees of freedom parallel mechanism, whose researches are relatively complex, the research is still in the initial stage, influencing the development and application of parallel robot. In this paper, a new type of non-symmetric 4-dof parallel robot 2PRS/2PRRS has been researched about its mechanism nature, which was verified through developing prototype and debugging on-lineFirst, based on the screw theory, a new type of non-symmetric 4-dof parallel mechanism (2PRRS / 2PRS) is synthesized, and I create the three-dimensional modeling and simulate the motion of the mechanism using the software Solidworks and ADAMS. From the motion simulation results, the mechanism has 4-dof, translation along X and Z axis, and rotation about X and Y axis.Secondly, the paper derives inverse kinematic resolution, positive solutions and jacobian matrix of the mechanism. And the velocity and acceleration are analyzed. Through the singularity analysis of the mechanism, it is concluded that the mechanism is singularity in the origin place when the moving platform is square. In order to avoid the singular location, there are two solutions for the moving platform. One is quadrilateral, not trapezoid, whose diagonal lines are perpendicular. Another is trapezoid whose diagonal lines are perpendicular. Contrast of the two schemes of singularity, workspace and flexibility. The performance of quadrilateral moving platform is good.Finally, the prototype is developed based on the above theoretical analysis. Then the moving platform's trajectory planning is finished. The mainly work of the prototype is cutting out'SIAT'in a spherical. After debugging on-line, the mechanism finishes the cutting work following the trajectory.In this paper, the analysis of the new mechanism is completed from synthesis of mechanism to prototype development and debugging on-line. The research of the new mechanism has important scientific research significance.