Today, interactive glass cockpit displays in aircraft look and behave very similarly to other computers, with windows and data that can be manipulated with point-and-click devices. As we see a growing adoption of natural, or post-WIMP (windows, icons, menus, pointer), HMIs in the general market—such as in smart phones, tablets, music, or video players—cockpit display system (CDS) suppliers are preparing now for the cockpits of the future, which will place the pilot at the center of the system. This objective will be achievable only if the proper engineering and design processes are deployed in conjunction with the proper development tools.
WIMP is often incorrectly used as an approximate synonym of graphical user interface (GUI). Any interface that utilizes graphics can be termed a GUI, and WIMP systems are a derivative of such systems. However, while all WIMP systems utilize graphics as a key element (namely the icon and pointer element) and therefore all WIMPs are GUIs, the reverse is not true—some GUIs are not WIMPs.
The primary benefit of WIMP systems is to improve the HMI by enabling better ease of use for nontechnical people, both novice and power users. Know-how can be ported from one application to the next, given the high consistency between interfaces.
Due to the nature of the WIMP system, simple commands can be chained together to undertake a group of commands that would have taken several lines of command line instructions. For the average computer user the introduction of the WIMP system has allowed for an expansion of users beyond the potential possible under the previous command line interface (CLI) systems.
User interfaces based on the WIMP style are very good at abstracting work spaces, documents, and their actions. Their analogous paradigm to documents as paper sheets or folders makes WIMP interfaces easy to introduce to novice users.
Furthermore, their basic representations as rectangular regions on a 2-D flat screen make them a good fit for system programmers. This explains why the paradigm has been prevalent for more than 20 years, both giving rise to and benefiting from commercial widget toolkits that support this style.
However, several researchers consider that there are applications for which WIMP is not well suited. This includes any application requiring devices that provide continuous input signals, showing 3-D models, or simply portraying an interaction for which there is no defined standard widget. These interfaces are called post-WIMP GUIs.
Post-WIMP comprises work on user interfaces, mostly GUIs, which attempt to go beyond the paradigm of WIMP interfaces, which are not optimal for working with complex tasks such as computer-aided design, working on large amounts of data simultaneously, or complex interactive systems. Post-WIMP interfaces have today made their way to the general public, including portable music players, smart phones, tactile tablets, and ATM screens.
Today most operational and flying cockpit HMIs, as the majority of desktop computers, are still based on WIMP interfaces—some of them standardizing upon the ARINC 661 international standard for interactivity management—and have started undergoing major operational improvements to surpass the hurdles inherent to the classic WIMP interface. These include the exploration of virtual 3-D space, natural interaction techniques for window/icon sorting, focus, and embellishment.
A natural user interface (NUI) is the common parlance used by designers and developers of HMIs to refer to a user interface that is (1) effectively invisible, or becomes invisible with successive learned interactions, to its users, and (2) is based on nature or natural elements (i.e. physics).
The word natural is used because in reverse, most computer or industrial interfaces use artificial control devices whose operation has to be learned. An NUI relies on a user being able to quickly transition from novice to expert. While the interface requires learning, that learning is eased through design which gives the user the feeling that they are instantly and continuously successful. Thus, natural refers to a goal in the user experience—that the interaction comes naturally, while interacting with the technology, and that the interface itself is natural.
An example of a strategy for designing a NUI is the strict limiting of functionality and customization, so that users have very little to learn in the operation of a device. Provided that the default capabilities match the user's goals, the interface is effortless to use.
In the early days of CLI, users had to learn an artificial means of input, the keyboard, and a series of codified inputs that had a limited range of responses, where the syntax of those commands was strict.
Then, when the mouse enabled the GUI, users could more easily learn the mouse movements and actions and were able to explore the interface much more. The GUI relied on metaphors for interacting with on-screen content or objects. The "desktop" and "drag" are examples, being metaphors for a visual interface that ultimately was translated back into the strict codified language of the computer. NUIs intend to provide direct and intuitive interaction between the user(s) and the system(s).
As far as aerospace is concerned, in today's most modern commercial airplanes, including all recent Airbus and Boeing planes (such as the A380, A350, and 787), the traditional “widget-based” (or WIMP) approach is mostly used for interactive cockpit displays. The main reasons—amongst many others—are the system certification needs for the highest levels of safety for these CDSs, which often require the use of already mature and trusted technology, but also some kind of “resistance to change” from crews and pilots—thus airline companies—who are used to flying with traditional user interfaces in the cockpit.
This article is based on SAE technical paper 2012-01-2119 by Vincent Rossignol, Esterel Technologies, and Christophe Bey, Ecole Nationale Supérieure de Cognitique.