0
Research Papers

Enhancement of Adaptability of Parallel Kinematic Machines With an Adjustable Platform

[+] Author and Article Information
Z. M. Bi1

Department of Engineering, Indiana University–Purdue University Fort Wayne, 2101 E Coliseum Boulevard, Fort Wayne, IN 46805-1499biz@ipfw.edu

B. Kang

Department of Engineering, Indiana University–Purdue University Fort Wayne, 2101 E Coliseum Boulevard, Fort Wayne, IN 46805-1499kang@engr.ipfw.edu

1

Corresponding author.

J. Manuf. Sci. Eng 132(6), 061016 (Dec 21, 2010) (9 pages) doi:10.1115/1.4003120 History: Received December 09, 2009; Revised November 19, 2010; Published December 21, 2010; Online December 21, 2010

The design of an industrial robot involves a number of conflicting objectives in general. A parallel kinematic machine (PKM) is known to achieve high precision and heavy load capacity but with the sacrifice of large workspace and high dexterity. Therefore, existing PKMs are mostly dedicated to a specific task with relatively poor adaptability to task variations. In this paper, the concept of an adjustable platform is proposed to enhance the adaptability of a PKM for various tasks. It is demonstrated that the adjustment of the dimensions of a base platform or end-effector platform has a significant impact on the performance of a PKM including its workspace and overall stiffness distribution. Both offline and online adjustment modes are presented. The offline adjustment brings a new dimension for reconfigurability and thus increases the versatility of a parallel robot for different tasks. The online adjustment turns a parallel robot into a redundant PKM, and therefore its overall performance against task requirements can be improved. A planar PKM and a Stewart robot with an adjustable platform are used as case studies in order to demonstrate the advantages of the proposed concept.

Copyright © 2010 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

Description of adjustment methods 1, 2, and 3

Grahic Jump Location
Figure 2

Design implementation for an adjustable platform: (a) structure I, (b) structure II, (c) structure III, and (d) structure IV

Grahic Jump Location
Figure 3

Planar PKM with an offline adjustable platform

Grahic Jump Location
Figure 4

(a) Workspace area versus d0 and (b) mean condition number versus d0

Grahic Jump Location
Figure 5

Workspace when (a) d0=0.3 m, (b) d0=0.5 m, and (c) d0=0.7 m

Grahic Jump Location
Figure 6

Workspace of the planar PKM when d0=0.1–0.9 m

Grahic Jump Location
Figure 7

Block diagram representation of Eq. 11

Grahic Jump Location
Figure 8

Graphical simulation of the planar PKM with an adjustable platform

Grahic Jump Location
Figure 9

Gain changes along the specified trajectory

Grahic Jump Location
Figure 15

Stewart robot with an online adjustable platform

Grahic Jump Location
Figure 16

Block diagram representation of Eq. 21

Grahic Jump Location
Figure 17

Gain vector measures along the specified trajectory

Grahic Jump Location
Figure 14

Comparison of the stiffness index along the trajectory: (a) offline and (b) online

Grahic Jump Location
Figure 10

Stewart robot with an adjustable platform: (a) general structure and (b) case structure

Grahic Jump Location
Figure 11

Workspace volume versus db

Grahic Jump Location
Figure 12

The average stiffness index versus db

Grahic Jump Location
Figure 13

Cross-sectional shapes for (a) ze=0.0635 m, (b) ze=0.0762 m, and (c) ze=0.0889 m The numbers indicate db.

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In