0
Research Papers

Wrench Capability of a Stewart Platform With Series Elastic Actuators

[+] Author and Article Information
Chawin Ophaswongse

Robotics and Rehabilitation
Laboratory (ROAR Lab),
Department of Mechanical Engineering,
Columbia University,
220 S. W. Mudd Building,
500 West 120th Street,
New York, NY 10027
e-mail: co2393@columbia.edu

Rosemarie C. Murray

Robotics and Rehabilitation
Laboratory (ROAR Lab),
Department of Mechanical Engineering,
Columbia University,
220 S. W. Mudd Building,
500 West 120th Street,
New York, NY 10027
e-mail: rcm2146@columbia.edu

Sunil K. Agrawal

Professor
Fellow ASME
Robotics and Rehabilitation
Laboratory (ROAR Lab),
Department of Mechanical Engineering,
Columbia University,
220 S. W. Mudd Building,
500 West 120th Street,
New York, NY 10027
e-mail: sunil.agrawal@columbia.edu

1Corresponding author.

Manuscript received September 21, 2017; final manuscript received December 12, 2017; published online January 29, 2018. Editor: Venkat Krovi.

J. Mechanisms Robotics 10(2), 021002 (Jan 29, 2018) (8 pages) Paper No: JMR-17-1309; doi: 10.1115/1.4038976 History: Received September 21, 2017; Revised December 12, 2017

This paper proposes a novel method for analyzing linear series elastic actuators (SEAs) in a parallel-actuated Stewart platform, which has full six degrees-of-freedom (DOF) in position and orientation. SEAs can potentially provide a better human–machine interface for the user. However, in the study of parallel-actuated systems with full 6DOF, the effect of compliance in series with actuators has not been adequately studied from the perspective of wrench capabilities. We found that some parameters of the springs and the stroke lengths of the linear actuators play a major role in the actuation limits of the system. This is an important consideration when adding SEAs into a Stewart platform or other parallel-actuated robots to improve their human usage.

FIGURES IN THIS ARTICLE
<>
Copyright © 2018 by ASME
Your Session has timed out. Please sign back in to continue.

References

Merlet, J.-P. , 2006, Parallel Robots (Solid Mechanics and Its Applications, Vol. 2), Springer-Verlag, Dordrecht, The Netherlands.
Pratt, G. A. , and Williamson, M. M. , 1995, “Series Elastic Actuators,” IEEE/RSJ International Conference on Intelligent Robots and Systems, Human Robot Interaction and Cooperative Robots, Pittsburgh, PA, Aug. 5–9, pp. 399–406.
Pratt, J. , Krupp, B. , and Morse, C. , 2002, “Series Elastic Actuators for High Fidelity Force Control,” Ind. Robot, 29(3), pp. 234–241. [CrossRef]
Robinson, D. W. , 2000, “Design and Analysis of Series Elasticity in Closed-Loop Actuator Force Control,” Ph.D. thesis, Massachusetts Institute of Technology, Cambridge, MA, p. 123. https://dspace.mit.edu/handle/1721.1/54838
Park, J.-H. , Stegall, P. , and Agrawal, S. K. , 2015, “Dynamic Brace for Correction of Abnormal Postures of the Human Spine,” IEEE International Conference on Robotics and Automation (ICRA), Seattle, WA, May 26–30, pp. 5922–5927.
Sugar, T. G. , 2002, “A Novel Selective Compliant Actuator,” Mechatronics, 12(910), pp. 1157–1171. [CrossRef]
Sugar, T. G. , and Kumar, V. , 2002, “Design and Control of a Compliant Parallel Manipulator,” ASME J. Mech. Des., 124(4), pp. 676–683.
Sergi, F. , Lee, M. M. , and O'Malley, M. K. , 2013, “Design of a Series Elastic Actuator for a Compliant Parallel Wrist Rehabilitation Robot,” IEEE International Conference on Rehabilitation Robotics (ICORR), Seattle, WA, June 24–26, pp. 1–6.
Erdogan, A. , Celebi, B. , Satici, A. C. , and Patoglu, V. , 2017, “Assist On-Ankle: A Reconfigurable Ankle Exoskeleton With Series-Elastic Actuation,” Auton. Robots, 41(3), pp. 743–758. [CrossRef]
Dwarakanath, T. A. , Crane , C. D., III , Duffy, J. , and Tyler, C. , 2000, “In-Parallel Passive Compliant Coupler for Robot Force Control,” 26th Biennial Mechanisms and Robotics Conference, Baltimore, MD, Sept. 10–13, pp. 587–594. http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.33.267&rep=rep1&type=pdf
Zhang, B. , 2005, “Design and Implementation of a 6 DOF Parallel Manipulator With Passive Force Control,” Ph.D. thesis, University of Florida, Gainesville, FL. https://pdfs.semanticscholar.org/7fa1/70a2d11bbafa959ce62465c2144137f894d7.pdf
Taghirad, H. , 2013, Parallel Robots: Mechanics and Control, CRC Press, Boca Raton, FL.
Tsai, L.-W. , 1999, Robot Analysis and Design: The Mechanics of Serial and Parallel Manipulators, 1st ed., Wiley, New York.
Nguyen, C. C. , Antrazi, S. C. , Zhou, Z. L. , and Campbell, C. E. , 1991, “Analysis and Implementation of a 6 DOF Stewart Platform-Based Robotic Wrist,” Comput. Electr. Eng., 17(3), pp. 191–203. [CrossRef]
Su, H.-J. , and McCarthy, J. M. , 2006, “A Polynomial Homotopy Formulation of the Inverse Static Analysis of Planar Compliant Mechanisms,” ASME J. Mech. Des., 128(4), pp. 776–786. [CrossRef]
Zibil, A. , Firmani, F. , Nokleby, S. B. , and Podhorodeski, R. P. , 2006, “An Explicit Method for Determining the Force-Moment Capabilities of Redundantly Actuated Planar Parallel Manipulators,” ASME J. Mech. Des., 129(10), pp. 1046–1055. [CrossRef]
Firmani, F. , Zibil, A. , Nokleby, S. B. , and Podhorodeski, R. P. , 2008, “Wrench Capabilities of Planar Parallel Manipulators—Part I: Wrench Polytopes and Performance Indices,” Robotica, 26(6), pp. 791–802. [CrossRef]

Figures

Grahic Jump Location
Fig. 1

Kinematic diagram of a parallel-actuated platform with SEAs

Grahic Jump Location
Fig. 3

Minimum potential energy field on a workspace at z = 0.165 m and in the neutral orientation

Grahic Jump Location
Fig. 4

Scenarios leading to actuation limits

Grahic Jump Location
Fig. 6

Explicit analysis results of force in the positive x direction (a)–(c), and moment in the positive z direction (d)–(f), with zero prescribed moment/force at z = 0.165 m and in the neutral orientation. (a) and (d) show the upper limit of force/moment. (b) and (e) show the lower limit. (c) and (f) represent the rigid actuator case (ks=5.0 N/mm, ℓs,0=±10.0 mm).

Grahic Jump Location
Fig. 2

Translational workspace in the neutral orientation

Grahic Jump Location
Fig. 5

Example of a feasible actuation set on a translational workspace at z = 0.165 m and in the neutral orientation (ks=5.0 N/mm, ℓs,0=±10.0 mm)

Grahic Jump Location
Fig. 7

Comparison of isotropic force and moment between two sets of spring parameters in a translational active workspace (a), (c), (e), and (g) in the neutral orientation, and a pitch-roll-yaw active workspace (b), (d), (f), and (h) at pB=[0,0,0.165]T m. The prescribed moment/force is set to zero.

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