Next Article in Journal
Vine-Inspired Continuum Tendril Robots and Circumnutations
Previous Article in Journal
Human-Robot Interfaces for Interactive Receptionist Systems and Wayfinding Applications
Article Menu
Issue 3 (September) cover image

Export Article

Open AccessArticle
Robotics 2018, 7(3), 57; https://doi.org/10.3390/robotics7030057

Maximal Singularity-Free Orientation Subregions Associated with Initial Parallel Manipulator Configuration

Computational Mechanics Laboratory, Universidade do Estado de Santa Catarina, Joinville-SC 89219-710, Brazil
*
Author to whom correspondence should be addressed.
These authors contributed equally to this work.
Received: 16 July 2018 / Revised: 10 September 2018 / Accepted: 11 September 2018 / Published: 18 September 2018
  |  
PDF [9764 KB, uploaded 18 September 2018]
  |  

Abstract

Reduced workspace is the main parallel robot disadvantage. It is generally due to the robot configuration, mainly the platform orientation constraint, the present work intends to find the maximum sphere within the orientation workspace, i.e., the singularity-free orientation regions. These regions are related to the platform orientation through Roll-Pitch-Yaw angles. Therefore, an optimization genetic algorithm is used to determine the initial platform orientation corresponding to the largest sphere volume. In this algorithm, the geometrical parameters and the direct and inverse singularities are the optimization constraints. The geometrical constraints may be studied using vectorial analysis. The reciprocity property from screw theory is implemented to analyze the direct and inverse kinematic. In this work it is used a methodology to verify the singularity closeness measure associated with direct kinematic. This measure is related to the rate of work done by each leg upon the platform twist. To determine how close is the parallel robot to a direct singularity a index value is proposed. It is considered that the passive joints reachable regions may be limited by a cone, whereby the cone symmetric axis is the same than the passive joint axis. In the optimization problem, the sphere volume, i.e., the maximal angular displacement of the moving platform around any axis is the objective function. Thus, the genetic algorithm individuals explore all feasible regions looking for an optimal solution. View Full-Text
Keywords: parallel robot; workspace; singularities; optimization parallel robot; workspace; singularities; optimization
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).
SciFeed

Share & Cite This Article

MDPI and ACS Style

Garcia, L.; Campos, A. Maximal Singularity-Free Orientation Subregions Associated with Initial Parallel Manipulator Configuration. Robotics 2018, 7, 57.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Robotics EISSN 2218-6581 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top