Design procedure for cuspidal parallel manipulators

In the design of parallel manipulators, a major problem is their reduced operational workspace. This is mainly due to the existence of a complex singularity locus within the workspace. The singularity-free workspace therefore corresponds to only a fraction of the potential workspace, and dimensioning the manipulator is intended to optimize such singularity-free workspace. The singularity locus often divides the workspace into isolated volumes according to assembly modes and working modes. As a result, it is common to restrict the operational space to a simple geometric shape inside a singularity-free workspace. However, it is well known that appropriate motion planning can make the most of a more complex workspace by means of transitions between working mode and/or assembly mode. In this paper, the authors obtain the locus of cusp points in the joint space entity, which will permit non-singular assembly mode changing in cuspidal manipulators. Making use of such entity, the optimum dimensional parameters are obtained which increase the possibility of non-singular transitions while obtaining a maximal, regular-shaped workspace.

[1]  Oscar Altuzarra,et al.  Defining Conditions for Nonsingular Transitions Between Assembly Modes , 2009, IEEE Transactions on Robotics.

[2]  Charles Pinto,et al.  Workspaces associated to assembly modes of the 5R planar parallel manipulator , 2008, Robotica.

[3]  Jadran Lenarčič,et al.  Advances in Robot Kinematics and Computational Geometry , 1994 .

[4]  Damien Chablat,et al.  Working modes and aspects in fully parallel manipulators , 1998, Proceedings. 1998 IEEE International Conference on Robotics and Automation (Cat. No.98CH36146).

[5]  Sébastien Briot,et al.  Self-Motions of General 3- RPR Planar Parallel Robots , 2008, Int. J. Robotics Res..

[6]  Damien Chablat,et al.  Non-Singular Assembly-mode Changing Motions for 3-RPR Parallel Manipulators , 2008, ArXiv.

[7]  Alon Wolf,et al.  Assembly Mode Changing in Parallel Mechanisms , 2008, IEEE Transactions on Robotics.

[8]  C. Innocenti,et al.  Singularity-Free Evolution From One Configuration to Another in Serial and Fully-Parallel Manipulators , 1998 .

[9]  Damien Chablat,et al.  Workspace and Assembly modes in Fully-Parallel Manipulators : A Descriptive Study , 2007, ArXiv.

[10]  R. W. Daniel,et al.  An Explanation of Never-Special Assembly Changing Motions for 3–3 Parallel Manipulators , 1999, Int. J. Robotics Res..

[11]  Jean-Pierre Merlet,et al.  Parallel Robots , 2000 .

[12]  K. H. Hunt,et al.  Assembly configurations of some in-parallel-actuated manipulators , 1993 .

[13]  Jadran Lenarčič,et al.  Advances in robot kinematics : analysis and design , 2008 .

[14]  Damien Chablat,et al.  Séparation des Solutions aux Modèles Géométriques Direct et Inverse pour les Manipulateurs Pleinement Parallèles , 2001, ArXiv.

[15]  Charles Pinto,et al.  Transitions between Multiple Solutions of the Direct Kinematic Problem , 2008 .

[16]  Damien Chablat,et al.  An Algorithm for Computing Cusp Points in the Joint Space of 3-RPR Parallel Manipulators , 2006, ArXiv.