Virtual reality...it's (not) only make believe: the design and build process for tractors has (virtually) undergone a complete restructuring.

With apologies to Conway Twitty, when you start to investigate virtual reality (read, almost real reality) technology, you quickly discover it is real; it's not only make believe. More than that, from limited beginnings, it has become positively commonplace.

But before you can appreciate where we are today, relative to the use of virtual reality, you need to see where we've been. So, let's take a trip back seven to eight years ago.

1995-1996

It's 1995, and the trade press is full of articles about the burgeoning new technology called virtual reality. Everyone has been blown away by the dinosaurs in Jurassic Park and the scenes from Forrest Gump, and after all, if you can make dinosaurs roam the earth again, couldn't you use the same tools to design a tractor?

In a mid-March article titled, "From movies to machines," Farm Implement News (FIN) reveals how Caterpillar engineers are using computer graphics programs similar to those that created those dinosaurs, "to model highly complex forms in three dimensions," and develop products (like the Challenger tractor) with curves of fiberglass instead of sharp welded angles of steel.

The article went on to discuss how John Deere used computer simulation sessions with farmers to fine-tune the ergonomics of the 8000 series tractor control panel.

In mid-July, a bulletin released by the North American Agricultural Equipment Conference provided a preview of a session in their upcoming annual conference to be presented by a Caterpillar engineer and a researcher from the University of Illinois-Urbana, entitled, "Virtual Prototyping." The presentation promised to show "how virtual reality (imaging) systems provide engineers with dramatic opportunities in computer-aided interactive design of machinery and hydraulic systems and the study of machine testing and performance."

Then in October, Resource magazine published an article, "A Real Look at Machine Design." Here, readers were told, "virtual reality facilitates ergonomic studies by placing you in the operator's station of the machine where you can look around to locate the controls and even relocate them to a more convenient location."

Clearly, industry was intrigued and excited by the possibilities promised by virtual design.

Words of Caution, Enthusiasm

In a November 9, 1995 article, Washington Technology offered these words. "Generating realistic virtual worlds requires capabilities still beyond the phone links and even the supercomputers available today.

"... The research firm Gartner Group expects VR use to be limited to research and niche applications at least through 2000. Gartner thinks desktop VR or 3-D visualization will be a widespread design technique by 1998. With desktop systems, users interact with their computer screens without being fully surrounded by the computer-generated world--a kind of ValuJet version of VR for those who can do without the frills."

In 1996, John Deere entered into a partnership with the Iowa Center for Emerging Manufacturing Technology (now the Virtual Reality Applications Center) at Iowa State University to investigate the use of virtual reality in product development.

According to the Virtual Reality Applications Center, the plan was an ambitious one, with the overall objective of developing "an operational system for creating a distributed, collaborative synthetic prototyping design environment."

Fast forward to this past summer and fall. Conversations with various industry figures make it clear that there are more facets to "virtual reality" than is widely understood. To clarify the subject, we went to the horse's mouth, and interviewed engineers from Case New Holland, John Deere and McCormick to get their perspective.

What we discovered is that there are various levels of technology involved.

Computer Assisted Design

Hovering over the entire field is the concept of "computer assisted (or aided) design."

Michael Ryken from John Deere explains, "Computer aided design is where the detailed design of individual parts is done. It is also where we determine how the parts attach to each other and function. We can then export to models we create in the CAD system into a polygonal format (triangles, rectangles, etc.) so we can use them in FEA (finite element analysis) or virtual reality (VR)."

Wayne Martenas from Case New Holland expanded on that point. "CAD capabilities allow digital analysis of complete machines--pre-test prototypes. You can combine experience gained from previous products in production to perhaps eliminate the first stage of an initial prototype. This allows you decreasing cost and time to market."

McCormick's Tom Ogle elaborates, "At McCormick, we use a CAD system which has integrated engineering analysis tools such as Kinematic Modelling, Finite Element Analysis, Computational Fluid Dynamics, etc. These tools utilize the core design data created by the CAD system, which provides a seamless exchange between the design environment and the analysis environment.

"The net effect is that these tools can be employed in the design process quicker and more effectively than before. This is vital in current marketing environments where short development lead times are required and engineering solutions have to be right the first time."

Some Definitions

Barrie Lindsay from McCormick offered these brief definitions of the primary CAD tools used by engineers.

Finite Element Analysis--Strength and fatigue life prediction of structural components such as Cab mounts, Transmission casings, Lift system components, Chassis frames.

Multi Body Dynamics--suspension systems (Cab and chassis)

To Martenas, finite element analysis is currently the most useful of the tools available. "FEA is a mature tool that is used for everything in the design process.

Kinematic Modelling--Motion of mechanisms such as hood supports, lift systems and linkage systems

"Historical design procedure can be defined as design, break, fix. You design the item, you see what it takes to break it, then you fix the design. Then you repeat the process until the product does what it needs to do. Finite element analysis allows the engineer to more accurately predict the strength of parts and products through simulation."

There is a significant difference between FEA and VR. Deere's Ryken explains, "FEA divides a structure into thousands of finite elements, then employs automated methods to calculate loads on each of them. In structural analysis, the automated methods involve writing force-displacement equations for each element, assembling these equations based on the continuity between the elements, and using the boundary conditions (how is one part attached to another part) and external forces and displacements to obtain a solution (typically stress, strain and displacement) for the deformed model. This type of analysis can be broken down into three general steps: 1) set up the model; 2) run the model; 3) review the results."

Ryken also provided this definition of virtual reality. "The definition of virtual reality contains two components; it is immersive and interactive. Immersive means that the virtual environment makes the user believe that he or she is in a place that they are really not. As an example, if we are evaluating a new tractor design, we can use a farm scene and the new tractor geometry with stereo viewing for depth perception, some physical operator controls (seat, steering wheel, etc.), sound and other sensory cues to make the user believe that they are driving a tractor around a farm. Interactive means that we provide ways for the user to interact with the virtual environment. Going back to the previous example, we can interact with the environment by providing the capability for the user to operate a virtual implement using the physical controls. In contrast to finite element analysis, analyzing designs using virtual reality can be broken down into two general steps: 1) set up the model; 2) review the model in r eal-time."

The Future is Now

Martenas offered the opinion that as engineers use computer models to a greater and greater extent, that the critical need today is for solid benchmarking information--such as can be obtained from a test track, etc.--where there is a repeatable process that can be documented, and the information applied to the computer models. This optimizes cost and materials through the use of digital prototyping.

At McCormick, Ogle said that the core CAD information is now used to provide input to 3-D visualization tools. They utilize a flat screen, which with the use of 3-D glasses, can display a 3D image of any component or complete tractor. "This is particularly useful in assessing new tractor styling and cab layout," he said. "Technology is also available to project the 3-D image Onto the walls of a four-sided 'Cave', which allows the engineer to be fully immersed in the virtual environment."

This is now relatively mainstream technology. Where just a few years ago, the entire field was solidly in the "gee whiz" category, today, Ryken says that, "Five years ago, John Deere was using virtual reality in a portion of the design process at two of its locations. Today, there are four locations that use virtual reality on a daily basis to assist in the design and development process."

This will lead to increased abilities to put new products on the market more quickly, and less expensively. And also opens the door to 'on-the-fly' design changes and customization.

Tom Johnson, from John Deere said, "The 'old' process was to design the product and hand off the design to the manufacturing organization to assemble. With virtual reality technology, design for manufacturing becomes more natural as the manufacturing discipline can communicate their needs (i.e. tool clearance, assimilability), during the product design cycle. The design changes for manufacturing can be communicated while the design is fluid and changes are more feasible, as opposed to waiting for the design hand-off."

Martenas continued, "If you have a design for a product that includes certain parts/sub assemblies and you want to change the design, as long as the replacements have been verified as well, you can substitute and change with a pretty high level of confidence that the change will work."

The Horizon Widens

With the advances in computer capabilities being made constantly, manufactures are constantly looking for the 'next level' of process improvement.

John Deere's relationship with the Virtual Reality Applications Center at Iowa State University has continued, and expanded. There are commercial software packages that include a VR application--EnSight for one--that allow engineering applications of VR without sophisticated software programming experience. And all major manufacturers are certain to be hip deep in VR applications sooner rather than later.

It is clear that VR technology will continue to play an integral role in the design and manufacturing of tractors and implements. Who knows: in the future it may be possible for users to take a virtual test drive on each and every one of the new models on your dealership floor... and each unit sold will be custom manufactured to meet customer specifications, virtually (sic) eliminating the need for on-site inventory.

Now that would be something exciting.