Research Papers

Kinematics of a Generalized Class of Pneumatic Artificial Muscles

[+] Author and Article Information
Girish Krishnan

Industrial and Enterprise Systems Engineering,
University of Illinois Urbana-Champaign,
Urbana, IL 61801
e-mail: gkrishna@illinois.edu

Joshua Bishop-Moser

Mechanical Engineering,
University of Michigan,
Ann Arbor, MI 48109
e-mail: joshbm@umich.edu

Charles Kim

Mechanical Engineering,
Bucknell University,
Lewisburg, PA 17837
e-mail: charles.kim@bucknell.edu

Sridhar Kota

Mechanical Engineering,
University of Michigan,
Ann Arbor, MI 48109
e-mail: kota@umich.edu

Image from www.wikipedia.com

1Corresponding author.

Contributed by the Mechanisms and Robotics Committee of ASME for publication in the JOURNAL OF MECHANISMS AND ROBOTICS. Manuscript received May 20, 2014; final manuscript received January 22, 2015; published online April 6, 2015. Assoc. Editor: Robert J. Wood.

J. Mechanisms Robotics 7(4), 041014 (Nov 01, 2015) (9 pages) Paper No: JMR-14-1115; doi: 10.1115/1.4029705 History: Received May 20, 2014; Revised January 22, 2015; Online April 06, 2015

Fluid filled fiber reinforced elastomeric enclosures (FREEs) have been a popular choice for actuators in prosthetics and soft robots owing to their high power density and cost effective manufacturing. While a narrow class of FREEs known as McKibben's actuators have been extensively studied, there is a wide unexplored class that could be potentially used as actuators and soft structural members. This paper analyzes the mobility of generalized FREEs based on simple geometric relationships that result from the inextensibility of fibers and fluidic actuation. The analysis conducted can be classified into instantaneous kinematics and global or large deformation kinematics. Instantaneous kinematics reveals that the most general deformation pattern of the FREE is a screw motion about the axis of its cylinder, whose pitch is a function of fiber orientations. Furthermore, a set of fiber angles, which do not deform under volumetric actuation were identified as the locked manifold (LM). Global kinematic analysis revealed that every FREE continued to deform until its fiber configuration approached the LM. These insights were corroborated with finite element analysis (FEA) and testing for a small sample of FREE actuators.

Copyright © 2015 by ASME
Your Session has timed out. Please sign back in to continue.


Howell, L. L., 2001, Axis and Circumference: The Cylindrical Shape of Plants and Animals, Harvard Press, Cambridge, MA.
Vogel, S., 2003, Comparative Biomechanics, Princeton University Press, Princeton, NJ.
Kelly, D., 1997, “Axial Orthogonal Fiber Reinforcement in the Penis of the Nine-Banded Armadillo (Dasypus Novemcinctus),” J. Morphol., 233(3), pp. 249–255. [CrossRef] [PubMed]
Kier, W. M., 1985, “The Musculature of Squid Arms and Tentacles: Ultrastructural Evidence for Functional Differences,” J. Morphol., 185(2), pp. 223–239. [CrossRef]
Silk, W. K., 1989, “On the Curving and Twining of Stems,” Environ. Exp. Bot., 29(1), pp. 95–109. [CrossRef]
Wainwright, S. A., 1982, Mechanical Design in Organisms, Princeton University Press, Princeton, NJ.
Gaylord, R. H., 1958, “Fluid Actuated Motor System and Stroking Device,” U.S. Patent No. 2,844,126.
Klute, G., Czerniecki, J., and Hannaford, B., 1999, “McKibben Artificial Muscles: Pneumatic Actuators With Biomechanical Intelligence,” 1999 IEEE/ASME International Conference on Advanced Intelligent Mechatronics (AIM), Atlanta, GA, Sept. 19–23, pp. 221–226. [CrossRef]
Peel, L. D., Muratalla, L., Baur, J., and Foster, D., 2011, “The Effect of Scale on Fluid-Filled Flexible Composite Actuators,” ASME Paper No. SMASIS2011-4934. [CrossRef]
Peel, L. D., and Ball, C., 2010, “Fabrication and Testing of a Simple ‘Bionic Arm' Demonstrator,” ASME Paper No. SMASIS2010-3658. [CrossRef]
Aschenbeck, K., Kern, N., Bachmann, R., and Quinn, R., 2006, “Design of a Quadruped Robot Driven by Air Muscles,” First IEEE/RAS-EMBS International Conference on Biomedical Robotics and Biomechatronics (BioRob 2006), Pisa, Italy, Feb. 20–22, pp. 875–880. [CrossRef]
McMahan, W., Chitrakaran, V., Csencsits, M., Dawson, D., Walker, I., Jones, B., Pritts, M., Dienno, D., Grissom, M., and Rahn, C., 2006, “Field Trials and Testing of the OctArm Continuum Manipulator,” IEEE International Conference on Robotics and Automation (ICRA 2006), Orlando, FL, May 15–19, pp. 2336–2341. [CrossRef]
Chou, C.-P., and Hannaford, B., 1996, “Measurement and Modeling of McKibben Pneumatic Artificial Muscles,” IEEE Trans. Rob. Autom., 12(1), pp. 90–102. [CrossRef]
Liu, W., and Rahn, C. R., 2003, “Fiber-Reinforced Membrane Models of McKibben Actuators,” ASME J. Appl. Mech., 70(6), pp. 853–859. [CrossRef]
Trivedi, D., Lotfi, A., and Rahn, C., 2008, “Geometrically Exact Models for Soft Robotic Manipulators,” IEEE Trans. Rob., 24(4), pp. 773–780. [CrossRef]
Kothera, C. S., Jangid, M., Sirohi, J., and Wereley, N. M., 2009, “Experimental Characterization and Static Modeling of McKibben Actuators,” ASME J. Mech. Des., 131(9), p. 091010. [CrossRef]
Philen, M., Shan, Y., Prakash, P., Wang, K., Rahn, C., Zydney, A., and Bakis, C., 2007, “Fibrillar Network Adaptive Structure With Ion-Transport Actuation,” J. Intell. Mater. Syst. Struct., 18(4), pp. 323–334. [CrossRef]
Bishop-Moser, J., Krishnan, G., Kim, C., and Kota, S., 2012, “Kinematic Synthesis of Fiber Reinforced Soft Actuators in Parallel Combinations,” ASME Paper No. DETC2012-71261. [CrossRef]
Bishop-Moser, J., Krishnan, G., Kim, C., and Kota, S., 2012, “Design of Soft Robotic Actuators Using Fluid-Filled Fiber-Reinforced Elastomeric Enclosures in Parallel Combinations,” IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), Vilamoura-Algarve, Portugal, Oct. 7–12, pp. 4264–4269. [CrossRef]
Peel, L., 1998, “Fabrication and Mechanics of Fiber-Reinforced Elastomers,” Ph.D. thesis, Brigham Young University, Provo, UT.
Krishnan, G., Bishop-Moser, J., Kim, C., and Kota, S., 2012, “Evaluating Mobility Behavior of Fluid Filled Fiber-Reinforced Elastomeric Enclosures,” ASME Paper No. DETC2012-71278. [CrossRef]
Bishop-Moser, J., Krishnan, G., and Kota, S., 2013, “Force and Hydraulic Displacement Amplification of Fiber Reinforced Soft Actuators,” ASME Paper No. DETC2013-12657. [CrossRef]
Bishop-Moser, J., Krishnan, G., Kim, C., and Kota, S., 2013, “Force and Moment Generation of Fiber-Reinforced Pneumatic Soft Actuators,” IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), Tokyo, Nov. 3–7, pp. 4460–4465. [CrossRef]


Grahic Jump Location
Fig. 1

FREEs consist of an elastomeric hollow cylinder pressurized with fluids, reinforced by two families of helical fibers. FREEs are inspired by (a) hydrostatic skeletons observed in squids and worms (reproduced with permission from Vogel [2], copyright 2003 by Princeton University Press), which in most cases have (b) equal and opposite fiber angles such that α = −β. (c) Spiral growth patterns of grapevine tendrils [5] and (d) mammalian penises (reproduced with permission from Kelly [3], copyright 1997 by Wiley) where it is shown that armadillo penis consists of fiber configurations with α = 0 deg and β = 90 deg) are shown to contain (e) asymmetric arrangement of fibers α ≠ −β.

Grahic Jump Location
Fig. 3

(a) Commercial examples of FREEs with equal and opposite fiber angle configurations, commonly known as McKibben pneumatic muscles2 and (b) potential applications of asymmetric fiber configurations demonstrated in manipulation

Grahic Jump Location
Fig. 5

Deformation parameters of a cylindrical FREE wrapped with a single family of helical fibers

Grahic Jump Location
Fig. 6

Design space spanned by the two helix angles with example geometries in various quadrants

Grahic Jump Location
Fig. 8

The instantaneous normalized pitch for quadrants I and II configurations

Grahic Jump Location
Fig. 9

Trajectory taken by the various initial fiber configurations toward the LM

Grahic Jump Location
Fig. 12

Verifying the large deformation behavior of FREEs using FEA and prototype testing (a) undeformed and (b) deformed configurations

Grahic Jump Location
Fig. 13

Fiber angle deformed trajectory comparison between kinematic analysis, FEA, and prototype testing




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