On Site Wearable Computer System*

Keywords

Figure 2. Input device/processor/battery

Figure 3. Options Considered for Dial

The software for these models consists of a hyper-text version of vehicle maintenance manuals. The manuals consist of both text and graphics in configurations that may have intermixed text and graphics. The coupling between the input device and the application software reflects the task orientation of this system. A dial is not an adequate general purpose input device but is specific to the maintenance task supported through hyper-text software where the user may be wearing gloves and where the system may be used in areas that have corrosive chemicals.

One of our major classes of applications for wearable computers is vehicle maintenance. As systems, e.g. aircraft and trucks, become more reliable and more complex, maintenance and repair become increasingly challenging problems. In maintenance, the individual field service engineer will not encounter enough failures of the same type from which to perceive a pattern and thereby develop a shortcut to diagnose the problem. Rather, each problem has to be time-consumingly diagnosed from first principles. A mobile information system can use highlighting and animation techniques to identify components and procedures necessary to replace them.

EVALUATION CRITERIA

As an example scenario, suppose the mechanic is in a limited space environment where the time to completion is extremely important and is attempting to trouble shoot a problem and/or replace a defective component. The mechanic must locate the information in the manual necessary to solve the particular problem. This possibly includes a trouble shooting check list or a graphic of the offending component. Once the necessary information has been located, the mechanic must view the appropriate portion of the information and use that information to either isolate the problem or replace the component.

Since our system involves hands free navigation through hyper-text documents, one issue that results is how to coordinate the hardware input devices with the software in the absence of a pointing device such as a mouse. We use a dial integrated with the processor housing as an input device and the software has specific hot-spots with associated links attached to meaningful locations in the text or graphics. The mechanic then turns the dial as a means of cycling through the hot-spots and depresses a switch to expand the desired link.

Another issue arises from the limited resolution (the Virtual Vision display being used for the model under current development is VGA) for light-weight display devices. Intermixed text and graphics require high resolution to understand. Techniques for solving this problem are currently being investigated.

A third issue involves the ergonomics of a wearable system. The system must be of light weight, must have batteries with a long life, and must be comfortable to wear. The current system is a pound and a half, belt or other body location worn and has a seven hour battery life. The display system must also be usable for reasonable periods of time without either eye or head strain. Field tests that are planned will isolate particular problems in any of these areas.

A final issue is the integrated size, shape and feel of the forms and functions of the housing and the user interface. The form is designed to reflect the type of usage and application of the system. Ideally, the housing and the style of the user interface are compatible and reflect the usage of the system. Currently, we use a standard user interface look and feel without consideration of the form of the housing but it is clear that in the future of task oriented computer systems, an integration of these elements is essential.