Research Papers

Characterization of an Electric-Pneumatic Hybrid Prismatic Actuator

[+] Author and Article Information
Paul J. Csonka1

Mechanical Engineering Design Division, Robotic Locomotion Laboratory, Stanford University, Stanford, CA 94305pcsonka@stanford.edu

Kenneth J. Waldron

Center for Automated Systems, University of Technology, Sydney NSW 2007, Australiakwaldron@stanford.edu


Corresponding author.

J. Mechanisms Robotics 2(2), 021008 (Apr 20, 2010) (8 pages) doi:10.1115/1.4001087 History: Received June 05, 2009; Revised December 08, 2009; Published April 20, 2010; Online April 20, 2010

Many high performance actuators have been developed in recent years. However, these actuators are generally designed for precise, relatively slow movements, or imprecise dynamic motion, but incapable of generating quasistatic trajectories. This dichotomy arises in part due to thrusting actuation technology that often trades off impulse for precision. A characterization of a bidirectional hybrid actuator developed for use in legged robots is described here. This actuator is capable of precise noncompliant positioning, and storage and rapid release of energy, which makes it equally suitable for static and dynamic positioning applications. Characterizations shown here allow tuning the actuator in future versions to reduce losses and increase efficiency.

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



Grahic Jump Location
Figure 2

Comparison of pre- and postcompression pressures in hybrid thrusting mode

Grahic Jump Location
Figure 1

Primary mechanical components include the motor A, isolation bearings, spline coupler B, pneumatic cylinder C, spline D, spline nut E attached to an extended hollow shaft F, piston brake G, roller-screw actuator H, roller-screw I, decoupling stage J that includes the power output point, and linear rail K. The arrows show component motions.

Grahic Jump Location
Figure 3

Net output force during electric charging of a compression thrust. The roller-screw begins to slip near the peak rated force of the pneumatic-assisted screw, eventually leading to significant deviation from the ideal model.

Grahic Jump Location
Figure 4

Magnitude plot of the ETFE, ARX, and single sine analysis results to validate the pneumatic model. The phase is not shown; the results are similarly close.

Grahic Jump Location
Figure 5

Comparing experimental and theoretical impulse response to validate the pneumatic damping ratio b†p

Grahic Jump Location
Figure 6

Comparison of pneumatic (solid line), and electric-pneumatic (dashed line) PID trajectories for a 40 mm position step input. Switching mode allows precise steady-state positioning

Grahic Jump Location
Figure 7

Mode of operation versus peak velocity, peak force, stiffness, and positioning resolution



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.

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