Analysis of Load Capacity on Spatial Rotation 4-SPS-S Parallel Manipulator

Load capacity of a spatial rotation 4-SPS-S parallel manipulator has been studied in this paper. The 4-SPS-S parallel manipulator has spatial three pure rotation degrees of freedom, including four SPS active legs and one passive constraining leg, which can be used as heavy-loading vehicle kinematic simulation devices, precise positioning mechanism of tunnel erecter assembly robots in tunnel shield machine and others. Based on the introduction and computation of the mechanism´s Jacobian matrix, the load capacity performance index is defined using Lagrange equation, also an analysis equation for assessing the load capacity of the parallel manipulator mechanism is built. Finally a numerical example is provided for analyzing the load distribution rules over the entire workspace. The paper provides important references for future mechanism design of this class of parallel manipulators.