Structural Snthesis And Mtion Analysis For 4-DOF 4-RCRP Smmetrical Prallel Mnipulators

Spatial imperfect-DOF parallel robots have received much attention for the advantages of their simple mechanism, low cost in designing, manufacturing, and controlling, comparing with traditional six-DOF parallel mechanism. Especially symmetric imperfect-DOF parallel mechanism with identical branch, symmetric construction, isotropic strukturele have bigger applicable potentiality. But the research development of imperfect-DDF parallel mechanism is very unbalanced, the research of two, three-DOF parallel mechanism have basically been finished, however the research of four, five-parallel mechanism dust begin, which limit the development and application of this kind of parallel mechanism to some extent.The subject of this paper is 4-RCRP four-DOF parallel mechanism, analyzing the kinematics of the mechanism, which have four DOF of three dimensional translational motion and revolution around Z axis, which is very promising imperfect-DOF parallel mechanism.First of all, this paper analyze the DOF and the input rationalities of the mechanism, according to geometrical features of the mechanism based on screw theory, setting up the restrict equation. solving the position of the mechanism using the continuation method. And use of Matlab software calculated the positive and negative solutions of the institution to verify the correctness of the solution.Second, the jacobian matxix of 4-RCRP parallel mechanism is established by using the method called imaginary mechanism, then establish the velocity equation, And draw the input velocity change curve under the condition of uniform motion of the motion platform.