Identification and analysis of robot manipulator singularities

Vassilios D. Tourassis, Marcelo H. Ang

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

The existence of singular positions inside the robot workspace is an inherent problem for task planning and robot control. At manipulator configurations near singular positions, very large joint motions are required to produce relatively small end-effector displacements. In the limit, when a singularity is encountered, the required joint motions become unbounded and the manipulator loses at least one degree of freedom. Identifying the singularities in the robot workspace is not always an analytically tractable problem, except for manipulators with opportune placement of the joint axes. Typically, it is easier and more informative to evaluate the robot 'arm' and 'wrist' singularities, which reflect the limitations of the lower-order robot subsystems responsible for positioning and orienting, respectively, the end effector in space. The objective of this article is to define analytically the interplay between the individual 'arm' and 'wrist' singularities and the global manipulator singularities. Specifically, a general formula that defines manipulator singularities in terms of the subsystem singularities is developed. The analysis leads to a novel, efficient method for identifying the singularities of six-axis manipulators. This is then illustrated through an example.

Original languageEnglish
Pages (from-to)248-259
Number of pages12
JournalInternational Journal of Robotics Research
Volume11
Issue number3
Publication statusPublished - Jun 1992
Externally publishedYes

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Robot Manipulator
Manipulators
Manipulator
Singularity
Robots
Robot
End effectors
Workspace
Subsystem
Robot Control
Motion
Placement
Positioning
Planning
Degree of freedom
Configuration
Evaluate

ASJC Scopus subject areas

  • Control and Systems Engineering

Cite this

Identification and analysis of robot manipulator singularities. / Tourassis, Vassilios D.; Ang, Marcelo H.

In: International Journal of Robotics Research, Vol. 11, No. 3, 06.1992, p. 248-259.

Research output: Contribution to journalArticle

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