Singularity Loci and Kinematic Induced Constraints for an XY-Theta Platform Designed for High Precision Positioning

Anas Hijazi, Jean-François Brethe, Dimitri Lefebvre

2018

Abstract

In this paper, the singularity analysis of an XY-Theta platform held by a serial redundant manipulator will be illustrated in details. This XY-Theta platform has a patented kinematics designed to keep the final position error below to 2 µm in its 300mm × 300mm workspace (Hijazi et al., 2015). These high performances are obtained due to the combination of three factors: proximity to a singular configuration allowed by a specific choice of the arm lengths to reduce the lever arm lengths, redundant kinematic chain to enlarge the dexterous workspace and a two-step control using mechanical breaks set up on the furthest joints and exteroceptive sensors in the final step. However, if the proximity of singularities is useful for the precision performance, it may also cause some control problems. Consequently, it is crucial to identify the singularity loci and the kinematic constraints they induce. This analysis is done in two cases: when the first joint is considered locked and the robot is not redundant anymore and when the robot can be controlled using the four joints. In the non-redundant case, the usual singularity surface degenerates into an helix. In the redundant case, singularity surfaces may appear in specific configurations. In both cases, the induced kinematic constraints are analyzed and strategies are proposed to overcome the problems.

Paper Citation

in Harvard Style

Brethe J. (2018). Singularity Loci and Kinematic Induced Constraints for an XY-Theta Platform Designed for High Precision Positioning.In Proceedings of the 15th International Conference on Informatics in Control, Automation and Robotics - Volume 2: ICINCO, ISBN 978-989-758-321-6, pages 39-48. DOI: 10.5220/0006827700390048

in Bibtex Style

@conference{icinco18,
author={Jean-François Brethe},
title={Singularity Loci and Kinematic Induced Constraints for an XY-Theta Platform Designed for High Precision Positioning},
booktitle={Proceedings of the 15th International Conference on Informatics in Control, Automation and Robotics - Volume 2: ICINCO,},
year={2018},
pages={39-48},
publisher={SciTePress},
organization={INSTICC},
doi={10.5220/0006827700390048},
isbn={978-989-758-321-6},
}

in EndNote Style

TY - CONF

JO - Proceedings of the 15th International Conference on Informatics in Control, Automation and Robotics - Volume 2: ICINCO,
TI - Singularity Loci and Kinematic Induced Constraints for an XY-Theta Platform Designed for High Precision Positioning
SN - 978-989-758-321-6
AU - Brethe J.
PY - 2018
SP - 39
EP - 48
DO - 10.5220/0006827700390048