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.