The Reality of Virtual Manufacturing
By David Blanchard
Editor
Caterpillar engineers test-drive new vehicle designs in a virtual world. (Photo courtesy Caterpillar, NCSA and Sense8.)
Virtual reality (VR) is a special kind of simulation that depends upon a human/computer interface technology that allows a three-dimensional, multi-sensory interaction between the user and the computer. With VR, instead of looking at a flat computer screen, the user interacts with a 3-D computer-generated environment, based on the way things work in the real world.
Thanks to excessive hype from the popular media, the predominant image of VR is of a drooling teenager wearing a bulky head-mounted device, zapping away at incoming spaceships that appear to be mere inches away. However, the reality (no pun intended) is that VR is very much a real-world grounded, business-oriented technology of particular interest to manufacturers.
For instance, virtual reality allows companies to bring employees from all phases of the manufacturing side into the design process much earlier, from those involved in the initial conceptualizing to post-production maintenance. VR is also being used for training purposes, allowing a company's best technology and personnel to be widely used in a number of locations, at any time.
Northrop (Hawthorne, Calif.), a defense contractor, is using workstation-based VR during the pre-production digital assembly of aircraft. By developing a very accurate high-fidelity digital prototype, Northrop hopes to reduce costs and significantly improve time-to-market.
Another defense contractor, Rockwell International (Thousand Oaks, Calif.), has developed software that can transform existing CAD data into a virtual environment. Engineers are able to visually determine how pieces of equipment will fit together by viewing them on a workstation, thereby eliminating the need to produce physical models of the parts.
Transcad (San Jose, Calif.), a semiconductor manufacturer, has designed an equipment data visualizer as a visual workstation front-end for viewing parts and assemblies linked to database tables. When a user clicks on component names and parts buttons, VR models appear in the main screen of the workstation. The user can navigate around them. The application makes it much easier to visualize thousands of part numbers and their descriptions.
Food manufacturer Nabisco (East Hanover, N.J.) has contracted for a complete VR solution to assembly line production. The company plans to train people on maintenance and service of the assembly line. A proof-of-concept system, developed by VR software provider Superscape (Palo Alto, Calif.), replicates the sounds of the assembly line starting up as well as shutting down, which lets operators know that the correct procedure has been followed on the virtual assembly line.
Motorola (Schaumburg, Ill.), a manufacturer of computer chips and other electronic components, has been using VR since 1994 and reportedly the technology is saving the company millions of dollars in training costs. Rather than flying trainees to dedicated training facilities, Motorola has begun using VR to deploy virtual worlds for on-site training at plants worldwide. It costs between $30,000-100,000 to build each customized virtual world, but the company expects a ten-fold savings since the virtual models can be modified on-site as equipment is upgraded or new employees are hired.
Automobile manufacturer Ford Motor Co. (Dearborn, Mich.) has made a major commitment to virtual environment technology for automobile design and engineering. The Advanced Vehicle Technologies group within Ford's CAVSE (Core & Advanced Vehicle Systems Engineering) division is using VR for simulations and virtual prototyping. Specific applications enhance aerodynamics, ergonomics and surface modeling.
Boeing Computer Services (Seattle, Wash.), a division of the aerospace company, is using a VR interface to a 3-D CAD system to evaluate the accessibility of aircraft cabins for maintenance workers. The system provides real-time, detailed images rendered at 100% accuracy.
I Feel the Earth Move... Virtually
Recently, Caterpillar (Peoria, Ill.), a manufacturer of construction, earth-moving equipment and engines, working with the National Center for Supercomputing Applications (NCSA) at the University of Illinois, developed a virtual environment for testing new machine designs. These tests assess the vehicle's design and determine visibility from the cab.
Caterpillar's use of virtual reality grew out of other computerized testing programs done in conjunction with the NCSA. In the past, an NCSA visualization specialist would spend weeks creating a computer animation that showed a new vehicle design.
A user's-eye-view from behind the wheel of a virtual tractor. (Photo courtesy Caterpillar, NCSA and Sense8.)
When Caterpillar engineers and others tried to evaluate the model by viewing the animation, the response was "if we could just change this part," or "if we could just see from this angle." Unfortunately, changing the model or viewpoint meant starting all over again, and it was decided that a more interactive way of viewing designs and integrating changes was needed.
Operators sit on a platform equipped with controls like those found in a real cab. The platform is placed in a CAVE (Cave Automatic Virtual Environment), a project-based VR system that surrounds the viewer with screens arranged in a cube.
Stereo images, with correct perspective and stereo projections, are displayed on the front screen, side screen and floor. The images change in response to the operator's head motion and use of the controls, creating a truly interactive environment. Using a 3-D wand, the operator can also "walk" around the vehicle and move freely in the virtual environment. This activity allows Caterpillar to assess the operator's view from the cab, test the ease of manipulating the vehicle, and evaluate other critical operation-related qualities of the design.
Traditional methods of testing require building a physical prototype for each design. The design of the model is then verified by an operator. Creating these models is both time-consuming and expensive:
Developing a physical prototype for testing can take several months. Such delays minimize the interactivity of the design process, limit the number of design alternatives that can be evaluated, and may discourage designers from trying new and innovative ideas.
Results from test driving a new, unproven design can be disappointing, or even dangerous.
WorldToolKit, a VR software development tool from Sense8 (Mill Valley, Calif.), integrates with Caterpillar's existing CAD system and simulation software. Caterpillar's machine designs are created using the Pro/Engineer CAD package from Parametric Technology (Waltham, Mass.), and then imported into the virtual environment. Caterpillar's own simulation software links the VR environment to the operator controls. This system allows Caterpillar to test new designs in a virtual world before building physical prototypes:
The time from design to test is reduced. "The entire process is much more interactive," said Kem Ahlers, manager of university relations for Caterpillar. "We can test more designs in less time, and easily make and test multiple modifications to a single design."
More testing early in the design process helps to ensure a quality design when the company does commit to a physical model. According to Dee Chapman, industrial consultant for the University of Illinois, "One key component to success is getting an operator involved in the design process as early as possible. We are now able to do that safely, before investing in a physical prototype."
Caterpillar's system runs in one of only three operating CAVEs in existence. Three Silicon Graphics Onyx Reality Engines project stereo images on the front wall, side wall and floor. IM
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