Research Papers

MAXFAS: Mechatronic Arm Exoskeleton for Firearm Aim Stabilization

[+] Author and Article Information
Daniel M. Baechle

U.S. Army Research Laboratory,
Materials & Manufacturing Science Division,
Building 4600,
Aberdeen Proving Ground,
Aberdeen, MD 21005-5069
e-mail: daniel.m.baechle.civ@mail.mil

Eric D. Wetzel

U.S. Army Research Laboratory,
Materials & Manufacturing Science Division,
Building 4600,
Aberdeen Proving Ground,
Aberdeen, MD 21005-5069
e-mail: eric.d.wetzel2.civ@mail.mil

Sunil K. Agrawal

Department of Mechanical Engineering,
Columbia University,
230 S.W. Mudd,
500 West 120th Street,
New York, NY 10027
e-mail: sunil.agrawal@columbia.edu

1Corresponding author.

Manuscript received January 5, 2016; final manuscript received June 6, 2016; published online September 8, 2016. Assoc. Editor: Jun Ueda. This material is declared a work of the U.S. Government and is not subject to copyright protection in the United States. Approved for public release; distribution is unlimited.

J. Mechanisms Robotics 8(6), 061013 (Sep 08, 2016) (8 pages) Paper No: JMR-16-1004; doi: 10.1115/1.4034015 History: Received January 05, 2016; Revised June 06, 2016

This article details the design, fabrication, and application of a mechatronic arm exoskeleton for firearm aim stabilization (MAXFAS), which senses and damps involuntary tremors in the arm. Human subject experiments were carried out using the device in a simulated shooting and aiming task. Results indicate that MAXFAS reduced arm tremors and improved shooting performance while wearing the device. Residual performance improvement after removing the device and possible training function of MAXFAS will also be discussed.

Copyright © 2016 by ASME
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Fig. 5

Anatomical degrees-of-freedom (left) and coordinate frames (right) of the arm

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Fig. 4

Raw and filtered gyroscope data. The isolated tremor signal oscillates about 0 rad/s.

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Fig. 3

Exoskeleton, frame, tension sensors, and motors

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Fig. 2

Upper arm (left) and forearm (middle) braces with IMU sensors. Braces with shoulder cuff, in rest position (right).

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Fig. 1

Illustration of arm exoskeleton

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Fig. 6

Illustration of the test setup (top) and image of subject in MAXFAS with airsoft pistol (bottom)

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Fig. 7

Experimental protocol

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Fig. 8

Average distance from shot to target center (accuracy) for the assisted (left) and unassisted (right) groups. Error bars represent standard error among subjects. Statistically significant comparisons are denoted by an asterisk.

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Fig. 9

Average precision (shot group dimensions) for the assisted (left) and unassisted (right) group subjects. Error bars represent standard error among subjects.

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Fig. 10

Average tremor amplitude without motor control, with control mode A, and with control mode B. Error bars represent standard error among subjects. Statistically significant comparisons are denoted by an asterisk.




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