Multi-Dimensional Performance Evolution and Evaluation From Traditional Stewart to 3–3 Orthogonal Parallel Mechanisms

Abstract A special type of Stewart mechanism, the orthogonal mechanism, is declared to have a special advantage in performance. However, the current study of orthogonal mechanisms lacks a systematic analysis that accounts for the advantage. Toward this goal, this paper studies multi-dimensional performance evolution and evaluation from traditional Stewart to 3–3 orthogonal parallel mechanisms. Six evaluation indicators named Good Displacement and Orientation Velocity Workspace (GDVW, GOVW), Good Force and Torque Payload Workspace (GFPW, GTPW), and Good Translation and Rotation Stiffness Workspace (GTSW, GRSW) are established to comprehensively evaluate the performance. This method can intuitively reveal the evolution trends of different performances, including motion/force transmission capacity, displacement and orientation velocity isotropy, force and torque payload isotropy, and translation and rotation deformation stiffness isotropy, within the different parameter spaces, which can provide guidance on the design of high-performance mechanisms. Results indicate that the performance of the orthogonal mechanism is better than traditional Stewart mechanisms in motion/force transmission capacity, velocity, and torque payload. Finally, the orthogonal mechanism is designed and adopted for application to validate the effectiveness.