EBACE Convention News

VR lends a helping hand

 - May 9, 2007, 11:17 AM

Dassault is increasingly using tactile virtual reality (VR) to design its Falcon business jets. Haptic (from the Greek for sense of touch) interfaces, such as force-feedback arms, allow engineers to better check maintainability early in the design phase. Along with several partners, the French manufacturer (Booth No. 7514) is integrating these tools into its Catia v5 product lifecycle management (PLM) suite of software programs.

“Haptic interfaces make virtual removal of a part easy,” Alexis Deneux, a Dassault design engineer specializing in methods and tools, told EBACE Convention News. For example, a human operator can use a force-feedback arm in a virtual environment. This type of arm has six degrees of freedom–three in rotation and three in translation (that is, uniform movement along a straight line). The operator sees the aircraft, or part of it, in three dimensions and seizes the part he has to remove. Every time the object collides with its housing, the operator feels it through the force-feedback arm. This allows him to determine whether he can find a reasonable way to extract the component.

In the past, such simulations were performed on real aircraft mock-ups, which involved much longer cycles. Also, they could not be done as early in the design process, and the earlier a problem is discovered, the cheaper it is to fix.

Operators can achieve three-dimensional vision in three ways: using stereoscopic goggles while watching a flat screen, using a virtual-reality helmet or entering a computer-generated “cave.” The cave is a 10-foot cube, where five of the six sides are screens that the human operator sees through special glasses. He is effectively surrounded by a computer-generated 3-D world. In the cave, infrared sensors tell the system where the operator is and what he is looking at and the virtual environment moves accordingly. Dassault does not have a cave and generally uses a flat screen with stereoscopic goggles.

Car maker PSA Peugeot Citroën uses haptic simulations in its “cave” at its design center near Paris. Engineers and production workers find them helpful to debug the final assembly of cars. This is important because if a major problem in the assembly process is discovered late in the program, it may translate into several months of delay.

Arm Lends a Hand with New Dassault Jet
Dassault used the force-feedback arm in the later stages of developing its Falcon 7X and now is using it at an early stage in its Neuron unmanned combat air vehicle program. It also is using it for the super-midsize business jet program that the airframer is poised to announce shortly.

So far, the company has used the haptic interface without a direct link to source data. “The PLM chain was interrupted because the haptic interface needed specific data preparation. Therefore, in the 7X program, a dedicated team used our haptic device to check maintainability,” Deneux explained.

Under a joint project called Rivage, Dassault and four French partners–haptic interface maker Haption, the CEA research center and car makers Renault and PSA–are improving haptic VR design technology.

Engineers have integrated the haptic interface into Dassault’s Catia v5 design software, which has yielded significant benefits. A small haptic interface called a spacemouse can be installed on a design engineer’s desktop computer allowing him or her to test a configuration any time. This greatly reduces the need for time in the virtual reality center, which can then be allocated to difficult or complex situations requiring a bigger haptic interface or better merging into virtual reality.

Rivage also is expected to provide replay capability.

Applications of the new system are just about to start, according to Haption’s managing director Jérôme Perret.

Haption, a CEA spin-off, has developed and manufactured all the haptic devices that Dassault and PSA use.

The group plans to develop enhancements in the level of reality–for example, the ability to determine collisions between an object and the operator’s arm, which is not possible now.

Deneux and his team also want to integrate flexible and deformable materials. And they would like to further refine the system to take into account the position of fingers, so, for instance, it could determine whether a maintenance technician can reach a particular screw behind a specific duct.