Orientation Singularity Analysis of Parallel Manipulators

Instantaneous kinematics and singularity analysis of three-legged parallel manipulators

Instantaneous kinematics and singularity analysis of a class of three-legged, 6-DOF parallel manipulators are addressed in this paper. A generic method of derivation of reciprocal screw and consequently, the instantaneous kinematics model is presented. The advantage of this formulation is that the instantaneous kinematics model possesses well-defined geometric meaning and algebraic structure. S...

Graphical Singularity Analysis of 3-dof Planar Parallel Manipulators

This paper introduces a new approach to identify singularities of planar parallel manipulators (PPMs). This method is based on Maxwell’s reciprocal figure theory which establishes a duality between self-stress frameworks and reciprocal figures. We use line geometry tools to introduce a new graphical construction called the Mechanism’s Line of action Graph (MLG). The MLG is introduced in order t...

Singularity Analysis, Constraint Wrenches and Optimal Design of Parallel Manipulators

Singularity Loci of Planar Parallel Manipulators with Revolute Joints

This paper addresses the problem of determining the singularity loci of 3-DOF planar parallel manipulators with revolute joints for a constant orientation of the mobile platform. The case when the base joints are actuated is of primary concern and is proved here to lead to singularity loci represented by curves of degree 42—an improved measure with respect to the one already given in the litera...

Uncertainty Singularity Analysis of Parallel Manipulators Based on the Instability Analysis of Structures

When all the inputs of a parallel manipulator (PM) are locked, the manipulator is usually turned into a structure. When an uncertainty singularity occurs for a PM, the latter structure is unstable or, in other words, it may undergo infinitesimal or finite motion. Hence, the investigation of the uncertainty singularities of a PM can be reduced to the instability analysis of its corresponding str...