Bethany Smith, Len Bass, Jane Siegel
Carnegie Mellon University
Pittsburgh, PA, U.S.A. 15213
E-mail: bethany@cs.cmu.edu
Phone: (412) 268-3558
This work supported by the U.S. Department of Defense
Our vision of the future of vehicle maintenance includes a computer system that is body worn, lightweight,
and enables hands free access to pertinent trouble shooting, procedural, and parts replacement information.
It also includes performing maintenance operations in a collaborative help desk mode where there are both
audio and video connections to colleagues who can assist both in suggesting alternative paths for
investigation during the trouble shooting and in suggesting procedures to simplify parts replacement.
A group at Carnegie Mellon University has been constructing a sequence of wearable computers. The latest
one whose construction has been completed (Oct ‘94) is intended for solo use, weighs 1.75 pounds
including batteries, has a 80386 processor, uses a head mounted Private Eye display device and a
customized input dial.
The dial, manipulated by hand, controls navigation through a hypertext representation of a check list used
during routine maintenance of amphibious combat vehicles now. The computer is also used to annotate the
checklist with results. This information is uploaded to a larger computer in a separate off-line operation to
expedite scheduling of repairs.
In the next iteration of this system (currently being designed) a speech input capability will be added. In
future iterations, a lipstick video, wireless networking and an incorporated full-duplex audio capability will
be added.
In addition, we expect continuing improvements in display devices. The Private Eye has a 720 pixel by 280
pixel resolution. In the system being designed, a Virtual Vision display with VGA resolution (640x480
pixels) will be used. Furthermore, in future iterations, improvements to display technology will allow more
and more information to be displayed on site.
The latest completed iteration of the wearable computer can be experienced in the "On Site Wearable
Computer" portion of the Interactive Experience track of this conference.
The maintenance information is represented in a hypertext representation. The links within the visible page
of the hypertext are maintained as a circular list (roughly). The dial is used to cycle through the links and
then follow a selected link. Speech provides a directly accessible method of following a link.
The business of vehicle maintenance is high pressure with short deadlines. Any tool used in this
environment must directly support the tasks of the worker. Thus, the style of the user interface is task-
oriented -- we are currently exploring ramifications of using the look and feel of the paper interface as work
proceeds prior to the final interface design for this product.
A number of questions arise with such a model. The most important is the effectiveness of the various
communication media in supporting particular maintenance tasks. A controlled experiment was performed
using students at the Pittsburgh Institute of Aeronautics and the results of this experiment are reported in the
short paper "An Empirical Study of Wearable Computer Systems" in this conference.
Abstract
This poster displays a vision of the future of vehicle maintenance. This future includes a wearable computer
system that can be operated with the mechanics' hands free. The computer system will provide necessary
information to solve maintenance tasks and to communicate with collaborators. The ability to support both
solo and collaborative maintenance activity, especially trouble shooting and the ability to effectively deliver
light weight, hands free information access will be achieved through improvements in both technology and
HCI. The poster displays the current state, a vision of the future and identifies the HCI and technological
improvements necessary to achieve this future state of vehicle maintenance.
Keywords
Wearable computers, body worn computers, task oriented computer systems, hands free maintenance, help
desks, vehicle maintenance, help desk collaboration
Introduction
Currently, vehicle maintenance workers must contend with a number of problems when they are trouble
shooting a defect or replacing a defective part. These problems include accessing the correct information in
a massive maintenance manual or parts catalog to diagnose the problem. Vehicle maintenance manuals are
changed very frequently (many on a ninety-day cycle), each vehicle is unique in terms of the collection of
components that comprise particular systems, only limited portions of the manual set can be taken to the
vehicle, and a bulky, hand-held walkie talkie is the only means of communicating with colleagues for
assistance. Furthermore, trouble shooting and repairing must be done under severe time constraints since it
costs hundreds of dollars for each minute of delay of an airplane awaiting departure at a gate.
REACHING THE FUTURE
The vision of the future that we have sketched depends on improvements in both technology and HCI
understanding. In particular, we have the following activities underway that will help in achieving this
vision:
Technology
The focus of the technological improvements necessary to enable the delivery of pertinent information to
the maintenance worker is a hands free, wearable computer system. Such a system will include a capability
for delivering the correct information for trouble shooting, procedural guidance and for parts replacement.
Furthermore, the computer system will present only the portions of the information that are relevant to the
specific vehicle being repaired. Finally, the computer system will support visual and audio collaboration
between the maintenance worker and either experts in particular subsystems of the vehicle or colleagues
who might be available to offer assistance.
Human Computer Interaction
Three different HCI problems must be solved in order to achieve our vision of the future: an appropriate
user interface must be designed that allows convenient access to information and collaboration using a
variety of different modalities, either jointly or in isolation; techniques supporting a help desk model of
collaboration must be developed and tested; and the computer system must be ergonomically sound. The
following activities are underway to assist in the solution of these problems:
User Interface Design
The user interface for the next iteration of wearable will support input in several different modalities
including speech and a specialized dial. These input modalities must be coordinated with the appropriate
representation of the maintenance information. For environmental reasons, it will not always be possible to
use speech for control and so the dial input mechanism must always be available. Thus, the user interface
design is centered around using the dial as an input mechanism and speech is viewed as a surrogate for the
dial with some accelerator capabilities.
Collaboration Models
The collaborative assumptions within the maintenance task are that the maintenance worker will be
supported by a local, but physically separated colleague or supervisor or a remote expert at a help desk
located at the vehicle manufacturer. The collaboration will be supported by both an audio and a video
connection.
User Testing
In order to assess both the ergonomics of the physical components of the device and the choices made in the
user interface design, we are testing each iteration. The latest completed iteration of the wearable has been
tested with U.S. Marines and the results of these tests will both inform future iterations of the wearable
computer and will be reported in a future document. Additional user testing is planned for the Summer of
1995 at the Pittsburgh Institute of Aeronautics. Also, ongoing field trials will accompany each cycle of
prototypes.
SUMMARY
In order to expedite the process of vehicle maintenance, we have sketched a future that involves a wearable
computer to deliver relevant information and to enable collaborative solving of maintenance problems.
Achievement of this future vision depends on technological improvements and achievement of greater HCI
understanding of collaboration.
ACKNOWLEDGEMENTS
The Pittsburgh Institute of Aeronautics and Davis Air have been very helpful in enabling the work
described and the development of the poster. Dan Siewiorek, Dick Martin, Asim Smailagic, John Stivoric,
Robert Kraut, Bonnie John, Kathleen Carley, David Miller, Malcolm Bauer and many others are all
involved in the on site wearable computer project at CMU.