Comparative Study of the Kinematic Performance Indices for the 3-U(RPRGR)RU and the 3-URU Parallel Robots

The research focuses on a novel three-degree-of-freedom parallel robot structure that is powered by using linear actuators, driving geared linkages. The main advantage of this design is the ability to avoid singular positions of first and second type as well as the large angular positions imposed on the links of the URU (U—Universal joint; R—Revolute joint) kinematic chains. The purpose of this article is to compare the kinematic performance of the 3-URU parallel robot with that of the robotic structure presented in this paper, the 3-U(RPRGR)RU parallel robot (P—Actuated prismatic joint; G—Geared transmission joint). To assess various configurations and compute the performance indices of the two given structures, and to compare them, MathWorks MATLAB was utilized. Analytical and numerical methods were used for determining the performance indices distributions. The obtained results show that the use of the actuating linkage improves the kinematic performance of the structure in the lower regions of the workspace.