The Kinematic Analysis And Simulation Research Of A Kind Of New Type 4-RPTR Parallel Mechanism

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, isotropy have bigger applicable potentiality. But the research development of imperfect-DOF 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 just begin, which limit the development and application of this kind of parallel mechanism to some extent. The subject of this paper is 4-RPTR four-DOF parallel mechanism, analyzing the kinematics of the mechanism, which have four DOF of three dimensional translation and revolution around Z spindle, 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 quality of the mechanism, setting up the restrict equation, solving the position of the mechanism with continuation approach, and numerical verification is carried out. Second, point to weak point which the numbers provided by mechanical direct kinematics is not directviewing, the problem of visualization of mechanical direct kinematics was solved in virtue of application software VB, AutoCAD, Matlab, the sketch of mechanical position was presented before designer in a very short time. Utilizing the analysis, the reachable workspace of mechanism was analyzed in virtue of the mathematic model of mechanism. and draw the shape of the reachable workspace under specific dimension, the corresponding volume and the cross-sectional area of the reachable workspace is obtained. according to the Jacobian matrix of mechanism, the singularity of the mechanism was analyzed. The jacobian matrix of 4-RPTR 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. Finally, the kinematics of the parallel mechanism is simulated by using ADAMS.