Research Of Dynamics And Uncertainty Of Output Influenced By Input Of 6-RSS Parallel Robot

Because of the merits of high structural stiffness, small motion inertia, high kinematic precision and so on, the parallel robot has obtained the more and more widespread application; but because of the more complexity in its structure, there are many difficulties in the study of the parallel robot. This paper studies dynamics of the parallel robot and how the input errors influence accuracy of the manipulator on the basis of 6-RSS parallel robot.At first, this article establishes the reference coordinate system and the moving axes, gives the system description method of the parallel robot under these two coordinate systems, and defines the structure parameter of the parallel robot. On this foundation, the math models of the forward solution and inverse solution about position is established. An iterative arithmetic that how to select initial value of forward solution of parallel robot is proposed, this method brings more astringency in forward solution.Next, the formulation of the dynamic model is studied. The mapping relation matrix from input speed to the velocity of the manipulator is inferred, and the mapping relation matrix from input speed to the velocity of links is inferred too, then at the base of equivalent circumrotate vector the mass force of the manipulator and links are formulated. The equivalent force that effects on drive shaft of the outside force including the mass force is established with Jacobian matrix, and then the whole math dynamic model of the parallel robot is formulated on this foundation. The model founded in ADAMS is analyzed in dynamics, and then the correctness of the math dynamic model is testified.Finally, how the input errors influence accuracy of the manipulator is studied. The assessment index that denotes accuracy of the manipulator is advanced, the mapping relation matrix from input errors to output errors is inferred. A concept of uncertainty of output is proposed on the basis of statistics theory, the output uncertainties influenced by input errors distribution is studied on this foundation.