Property Analysis of the Position-Singularity Loci of the Stewart Manipulator Using the Cross-Section of Z-Plane

【摘要】：正This paper addresses the property analysis of the position-singularity loci of 6/6-SPS Stewart manipulators. After constructing the Jacobian matrix of the 6/6-SPS Stewart manipulator,a cubic polynomial expression in the mobile platform position parameters,which represents the constant-orientation position-singularity locus of the manipulator,is derived.Graphical representations of the position-singularity locus of the manipulator for different orientations are illustrated with examples to demonstrate the theoretical results.Based on this analytical expression,a quadratic expression that represents the position-singularity locus of the manipulator in Z-plane is derived,and further the property of position-singularity loci of the manipulator in parallel Z-planes is identified.It shows that position -singularity loci of 6/6-SPS Stewart manipulators in parallel Z-planes are all quadratic expressions which include infinite hyperbolas,four pairs of intersecting lines and a parabola.