From handheld devices to the cockpits of fighter jets, display technology design matters.
In the last article, we talked about a few key technologies that have been key to the development of touchscreen displays, namely capacitive and resistive touchscreens, as well as haptics. Here, we’ll discuss a specific example of display design for aerospace applications—the F/A-18 Super Hornet.
The Birth of the PalmPilot
The PalmPilot, a simplified Personal Digital Assistant (PDA) or palmtop computer, had four functions: memos, calendar, address book, and to-do lists. The device first came on the scene in 1992. It was produced by Palm, Inc. In 1995, U.S. Robotics purchased Palm and increased production. Later, U.S. Robotics was acquired by 3Com in 1997. Today, HP owns 3Com.
The Burr-Brown ADS7843 was one of the first touch screen controllers in the late 90s. This IC had an architecture based on capacitive redistribution with a sample-and-hold and a Successive Approximation Register (SAR) A to D converter.
Touch screens have advanced quite a bit since then. We will take a look at some problems and solutions with touchscreens in mission-critical applications.
F/A-18 Super Hornet Display
Let’s take a look at the F-18 Super Hornet which Astronaut Matthew Dominick flew while in a Navy Strike Fighter Squadron. The following image shows the large area display that the pilot sees. The pilot can arrange various display formats on the touchscreen and even re-size them to meet their needs. This helps decrease the workload for the pilot. When the pilot touches a keyboard display, each button responds with a brightened key image as feedback.
Figure 1. The Advanced Cockpit of the Block III Super Hornet. The display in the center replaced a series of four displays in the Block II Super Hornet. (Image from Boeing)
Astronaut Matthew Dominick discussed touchscreens with podcast interviewer Dave Finch on Moore’s Lobby. Dominick said, “Have you ever used a touchscreen device, and you touched it, and didn’t get the response you wanted?”
Dominick commented, “….when you push something and don’t get a response 4 or 5 percent of the time, that’s a huge failure rate.” Another number that a professor gave to him was 50 ms. So if you make an input to a device via a tactile button or on a touchscreen, if you don’t get a response within 50ms, it enters the annoying phase and you are very likely to press it twice.
In the F-18 Super Hornet, Dominick says that when he pushed a button he needed to see a response. In the older Hornet displays, there was the display in the middle and there about 20 tactile pushbuttons around the outside of the screen. You would push them and you would get a response every time. The response time was nearly instantaneous. There was a tactile feedback. He could put his finger on the button and be looking outside to see what was going on or looking at another display and push a button and he would get that sensation in his finger that it was indeed pressed and he did not have to be looking at it.
In the Super Hornet, shown above, there was a screen that had the feeling of a touchscreen but was not one really—-there was no tactile feedback, the pilot had to stare at the display. “Latency, as in RF, is incredibly annoying”, commented Dominick.
Recently, the US Navy received their new F/A 18 Super Hornets with improved upgrades.