Mercedes' virtual reliance: the centerpiece of Mercedes' design strategy isn't real. It's virtual

Automotive Design & Production, Oct, 2003 by Kermit Whitfield

"Virtual reality is the backbone of engineering for us," says Dr. Bharat Balasubramanian, vice president of development for Mercedes-Benz passenger cars, while standing within the virtual reality (VR) center at the Mercedes-Benz Technology Center in Sindelfingen, Germany, where all Mercedes-Benz vehicles are designed. The importance of VR at Mercedes can be assessed from the fact that the VR center opened a mere three years ago in April 2000, but was doubled in size a year later. Now it's a critical part of Mercedes' ambitious plan to make twice as many new models in half the time it did just a few years ago. (Ten new vehicles in the four year period ending with 2005 is the goal.)

Balasubramanian says the initial hurdle that VR had to overcome was convincing executives that were used to seeing and touching clay models that they could make design decisions based solely on 3-D projections. The development of the SLK, he explains, helped accomplish this in that the executives saw that their VR-based decisions were precisely reflected in physical models. Now every development program has a digital phase that simulates packaging, functionality, assembly and durability, and leads directly to the creation of a physical model. For major model changes, Balasubramanian says the development process involves three full cycles where VR simulations lead to the creation of prototypes, and information taken from the prototypes are used to refine the VR model. For minor changes or model variants only one or two cycles are required.

Although a great deal of public attention is on the simulation of entire vehicles, 70% of all VR simulation time at Sindelfingen is centered on component-level work: checking the relationship of parts of one another. Ergonomic studies also consume lots of time in the VR environments known as "CAVEs" (Cave Automatic Virtual Environments), where full-size, 3D images are projected on three walls. For example, to test driver ergonomics, special interior bucks are rolled into the CAVEs that employ force feedback to combine with the VR images and create realistic driving experiences. Also, 800 Sindelfingen workers, who have been classified by height and weight and indentified as test subjects, "drive" the bucks to help Mercedes ensure that future vehicles can be operated by a wide range of people. (Interestingly, Balasubramanian says that a vehicle interface similar to BMW's complicated iDrive was tested at the VR center, but the feedback indicated that a simpler system was needed.)

While reducing the time and costs associated with building physical prototypes are usually cited as the chief reasons Sot the expanded use of VR in automotive development, Balasubramanian says that Mercedes is not participating in the race to shave as many months as possible ors of development schedules. He expects that even with the extensive use of VR the development of all-new vehicles will still take between 30 and 40 months. And though this time is significantly shorter than in the pre-VR era and is the key to Mercedes aggressive new model plan, speed is not the main goal. "We are trying to achieve high product maturity," he says, "We're not trying to be the fastest."

BETTER MOLD STEEL

As automotive designers pursue mare ambitious uses of plastics, the pressure is on mold tool makers to continually improve their products. Recognizing the need For higher performing fool steels, Bohler Uddeholm [Rolling Meadows, IL) has developed a new premium grade stainless tool steel called Stavax Supreme, that if says solves many of the current problems of mold tool steels. Top on the list is greater corrosion resistance. Bohler Uddeholm's technical manager, James Kaszynski, points out that molders can experience a lot or down time because of corrosion-related maintenance like surface re-polishing and coaling channel re-drilling. Corrosion also causes higher reject rates, especially for molders of high-quality transparent parts like automotive lenses. He says Stavax Supreme is far more corrosion resistant than current mold steels which confers many benefits: lower mold maintenance costs, elimination of humidity protection, and better heat transfer characteristics and cooling efficiency for more consistent cycle times. Kaszynski says that the steel is also crack resistant, has good ductility and toughness and excellent through-hardening properties. Bohler Uddeholm is targeting second tier lighting suppliers and currently has 12 trials underway in North America and 10 in Europe.--KEW

COST VS. TECHONOLGY

The near-constant talk in the industry about lowering costs and, by association, using China as a supply base has a number of suppliers in high dudgeon, and suggesting it could put a chill on technical innovation. However, Delphi's vice chairman and chief technology officer, Don Runkle, doesn't quite see it that way.

"Each OEM has a different perspective in terms of cost and innovation," he said, adding, "You can't say that all OEMs are the same," according to Runkle, "because they each have a distinct business model that follow. Still," he says in a manner that puts an emphatic close to the cost question, "automakers often get the suppliers they deserve."