A 3-DOF Parallel Mechanism Sensitivity Analysis and Parameter Sensitivity Analysis

In this paper, the error analysis of 3-PUU three-dimensional translational parallel mechanism (the mechanism consists of three limbs, each of which consists of a prismatic pair and two universal hinges, this is called 3-PUU, P represents prismatic pair, U stands for universal hinges) is studied. First, the geometric error sources are isolated by using the vector chain method, and the relationship between the end position error and the geometric error sources is constructed. Second, the error of the branched chain can be accumulated to each branched chain on the x-, y- and z-axes, then the parallel mechanism has tight coupling and nonlinear characteristics. In order to acquire the influence aimed at the end position of the mechanism, each chain error values ∆x, ∆y, ∆z is taken to the direct equation, respectively. Consequently, different chain error would lead to different end position error of the mechanism, which provided a theoretical basis for designing mechanism.