NBAA Convention News

At Dassault, designers step into virtual creations

 - September 30, 2008, 7:16 AM

Dassault Falcon (Booth No. 235) has created a “virtual reality room” that lets aircraft designers step into the digital creations they have crafted on their Catia design screens to make sure every detail is right before ever building the real thing.

For all its new airplane designs, Dassault is using the “immersive” virtual reality chamber and special features such as force-feedback arms and virtual images that shift according to the user’s position and movement. Since April, engineers have relied on it to verify, in full scale, practical aspects of aircraft designs. The super-midsize Falcon business jet (code-named SMS) will be the first to benefit, right from the start, from the new facility that NBAA Convention News visited last month.

“We are bringing more physical feel into virtual reality,” said Alexis Deneux, who is in charge of analysis for the “methods and tools” team at the manufacturer’s headquarters in Saint-Cloud, France. The immersive room actually does better than a physical prototype would, as aircraft always appear at a scale of 1:1. One UAV designer (the room is also used for Dassault’s defense business) recently “told us he had never realized the actual size of the bay he was working on, before coming here,” Joyet said.

An earlier virtual reality room, even though a major advancement, did not offer this benefit. “In the virtual reality room, you can zoom in on a bolt and have it magnified 20 times,” Joyet pointed out. Another effect is the user always approaches an object from its general aspects first; details come second.

In the immersive room, the user wears stereoscopic glasses that enable three-
dimensional viewing on the main display. His head, upper arms and hands are fitted sets of small spheres that help infrared cameras track his body’s position and where he is looking. The images on the main display move accordingly.

While the main user looks through the glasses, other users can observe the action on the two secondary displays. The upper one shows the main user’s viewpoint. On the lower one, viewers can choose a different viewpoint and thus suggest alternate actions to the main user.

For some maintainability tests, the back of the user can be tracked, too, to detect possible obstructions by any part of the aircraft. For more precision, fingers will be tracked soon as well, Deneux said. Eventually, complete virtual character may appear on the display. In the near future, maintenance procedures may be described in a movie recorded from the main display in the immersive room.

NBAA Convention News tried the virtual replacement of a servo-control. Every time the object collides with its housing, the human operator feels it through the force-feedback arm. He thus can determine whether there is a reasonable way to extract the component. “The human brain can find the right path thanks to force feedback,” Joyet explained. Once the path is found from a geometric viewpoint, some practical aspects still need to be solved. When the force-feedback arm simulates the weight of the servo-control (40 pounds), for example, the operator realizes he needs tooling to handle it.

In the past, such simulations were performed on real mockups and involved much more time. Also, they could not be done as early in the design process as they can now. The earlier a problem is discovered, the less expensive it is to fix, engineers point out.

The immersive room can also be used for cabin completion design. Catia data can be uploaded into Dassault Systèmes’ Virtools development platform. Virtools employs realistic high-rendering graphics used in video games, for which it was originally designed. It can be used to check whether a folding table is properly located relative to other furniture. Or, when sitting in the virtual lavatory, the user might realize one handle on the sidewall is positioned behind him rather than in front of him, where it belongs.

Little training and no preparation is needed to use the room. What engineers see in the immersive room is what they see on their Catia workstations. They are even used to moving in three dimensions in their virtual mockup, thanks to so-called spacemouses (cursor control devices that can move in 3-D). But they see–or feel–the virtual mockup in a more realistic way. “We want this to be a usual tool,” Joyet said.

He added that he considers an immersion session successful when engineers start joking, “I’m pushing the throttles, let’s take off.” Also, according to Joyet, there have been more and more bookings since April, when the room became operational. One reason is the design of the SMS, now in the preliminary phase, is gaining momentum.

The immersive room was developed in conjunction with car manufacturers PSA Peugeot Citröen and Renault. Automotive and aerospace industries, in this field, can have similar needs. However, according to Deneux, car makers still use prototypes (complete or partial), while Dassault has dropped them.

In the future, flexible materials will be simulated, too. Another addition will be a virtual-reality helmet. “It provides total immersion, which is interesting but is more complicated to use because the user’s entire body needs to be fitted with trackers,” Deneux noted.