0
Technical Briefs

Disturbance-Observer-Based Force Estimation for Haptic Feedback

[+] Author and Article Information
Abhishek Gupta

Department of Mechanical Engineering, Indian Institute of Technology, Kharagpur, WB 721302 Indiaabhi@mech.iitkgp.ernet.in

Marcia K. O’Malley1

Department of Mechanical Engineering and Materials Science, Rice University, Houston, TX 77005omalleym@rice.edu

1

Corresponding author.

J. Dyn. Sys., Meas., Control 133(1), 014505 (Dec 02, 2010) (4 pages) doi:10.1115/1.4001274 History: Received November 17, 2008; Revised November 03, 2009; Published December 02, 2010; Online December 02, 2010

In this paper, we propose the use of a nonlinear disturbance-observer for estimation of contact forces during haptic interactions. Most commonly used impedance-type haptic interfaces employ open-loop force control under the assumption of pseudostatic interactions. Advanced force control in such interfaces can increase simulation fidelity through improvement of the transparency of the device. However, closed-loop force feedback is limited both due to the bandwidth limitations of force sensing and the associated cost of force sensors required for its implementation. Using a disturbance-observer, we estimate contact forces at the tool tip, then use these estimates for closed-loop control of the haptic interface. Simulation and experimental results, utilizing a custom single degree-of-freedom haptic interface, are presented to demonstrate the efficacy of the proposed disturbance-observer (DO)-based control approach. This approach circumvents the traditional drawbacks of force sensing while exhibiting the advantages of closed-loop force control in haptic devices. Results show that the proposed disturbance-observer can reliably estimate contact forces at the human-robot interface. The DO-based control approach is experimentally shown to improve haptic interface fidelity over a purely open-loop display while maintaining stable and vibration-free interactions between the human user and virtual environment.

FIGURES IN THIS ARTICLE
<>
Copyright © 2011 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

Single degree-of-freedom haptic interface

Grahic Jump Location
Figure 2

Measured (dashed) and estimated (solid) contact forces during free space interaction

Grahic Jump Location
Figure 3

Measured (dashed) and estimated (solid) contact forces during virtual wall interaction (K=800 N/m)

Grahic Jump Location
Figure 4

Transparency bandwidth for (a) open-loop, (b) closed-loop, and (c) disturbance-observer based controllers (wall stiffness=800 N/m)

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