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Motion analysis becomes user-friendly

Motion analysis becomes user-friendly

San Mateo, CA-Traditional motion-analysis tools can prove difficult to use, run only on UNIX workstations, and cost more than $20,000. With these drawbacks pitted against it, it's little wonder that motion-analysis has been closeted in large companies with the resources to create specialized analysis teams. Don't despair, however. A small company in northern California hopes to change that perception with the introduction of its Working Model software. Here's why.

Working Model v2.0 runs on a PC, features a graphical user interface, and costs less than $1,500. The program enables engineers to construct and test prototypes, explore new designs, conduct extensive "what-if" analyses, and refine simulations. It also lets users quickly and easily make physically accurate animations and export them to other applications.

Only four years ago, Knowledge Revolution was an educational software company producing high-end, physics-based programs. However, users of its Interactive Physics software tried to use the product to solve mechanical engineering problems. Realizing the need for motion analysis at the design engineer's level, the company built on its existing technology to develop what has become its second-best-selling product-after only one year on the market.

Engineers who developed Working Model v1.0 had several goals in mind: Ease of use, speed, and tight integration between dynamics and animation. The most noticeable feature is the interaction between the user and the software. For example, hitting "run" gives the user immediate feedback with no pre- or post-processing required. "The good thing about Working Model," says Dave Buszucki, president of Knowledge Revolution, "is that customers told us what they wanted."

Still, users weren't satisfied with the first version. Pete Geottner, director of marketing, explains: "We didn't realize how much people wanted to use their existing CAD drawings with our software." As a result, v1.0's interface and DXF-import capabilities were weak.

The company improved the interface and rebuilt the entire DXF import facility in v2.0. But improvements didn't stop there. The engineers turned to their technical-support database to gain a better understanding of what customers wanted. Seven of the nine major features in v2.0 were customer-driven, including:

A Dynamic Data Exchange (DDE) interface that lets users tie into other programs on-the-fly.

  • Constraints, such as internal and planetary gears and slider joints.

  • Tools for CAM design and analysis, such as curved slot joints.

Making work easier. Version 2.0's interface offers automatic defaults for each property in the software. Users can design an entire system graphically-without specifying any values or equations. And to let users customize the program, the interface features a flowing windows scheme for entering properties. When a user selects an object, Working Model automatically recognizes it, provides pertinent information for the object, and lets the user modify only that information.

Working Model also features robust automatic collision detection, something many other simulation packages don't provide. And the improved collision algorithms in v2.0 allow users to solve the most difficult problems faster. Says Umberto Milletti, director of product development, "There was a dramatic improvement and we received very positive customer feedback."

Why motion analysis? Design challenges aside, one of the biggest obstacles to the success of Working Model, says Goettner, is that many design engineers don't yet understand why motion analysis is important to them. That may be partially due to the inaccessibility of motion-analysis tools.

With the release of Working Model, engineers are gradually recognizing the value of motion analysis. They are already using the product for: design verification; testing designs in virtual environments, such as underwater; inverse dynamics; product visualization; calculation of forces for FEA models; measuring design parameters difficult to measure in the real world, such as with very small parts; destructive testing; and even product demonstrations.

Sergei Fedorjaczenko, design engineer at Carlingswitch in Plainville, CT, is using Working Model to explore ideas. Before building prototypes of the company's switches and circuit breakers, Fedorjaczenko tests new mechanism concepts by running software simulations. Traditionally, engineers at Carlingswitch would spend four to six weeks building parts and testing a prototype. Now, Fedorjaczenko can evaluate a concept in under one week.

But adopting Working Model wasn't automatic. Initially, Fedorjaczenko used the software to simulate existing mechanisms. He then correlated the simulations with results from real life tests. "The comparisons gave me confidence in Working Model because the results were very close," says Fedorjaczenko.

After a few months, the company began implementing Working Model in the design process for future products. The long term goal, says Fedorjaczenko: "To use mechanism analysis on all of our designs, right from the start."

To buy or not to buy. This past year, Emerson Electric wanted to purchase a company that makes a specific type of patented pliers. But it needed to research similar patents to avoid any future conflict.

Emerson discovered a patent for a similar tool and wanted to make a comparison. The company had drawings and a brief description of the product, but several questions remained.

Instead of using a simple pair of pivoting jaws, the pliers use a pall mechanism that slides up and down a toothed slot. Joe Gierer, senior analytical engineer at Emerson's Specialty Products Div. in St. Louis, MO, used Working Model to analyze the mechanism.

"We were able to show how the pall mechanism engages as you try to grab a workpiece, what happens when you release pressure on the handles, and what the tool would do when just sitting on a table," explains Gierer. "It was a pretty successful analysis," he adds. Emerson then made prototypes of the pliers and verified that it functioned as Working Model had predicted.

"I had my analysis going in just three days and was getting results that I trusted," Gierer says. "The short learning curve was a really big plus. Many products take weeks or even months to learn."

Not just another design tool. With about 75 to 80% of its users working in mechanical design, Working Model seems to have found its niche. But it does much more than straight product design.

Dr. Gary Slone, an Olympia, WA-based ergonomist who frequently serves as an expert witness, uses the software faithfully for accident reconstruction. Case in point: A child entered a fast-food restaurant and approached the condiment station. Unable to see above the table, the boy grasped its edge and attempted to lift himself up. The table fell on top of him, causing serious injury. Investigating whether the table was properly designed, Slone reconstructed the entire accident in Working Model, simulating both the table and the child.

The 5-ft-long table has a pedestal base at each end with four legs on each base. When Slone simulated the incident using the actual table design, the table fell. However, rotating the legs 45 degrees indicated that they could have provided the support needed to keep the table upright. The simulations successfully proved that the legs did not properly align with the table, and that the accident was the result of a poor design.

Analysis in motion. Examples of Working Model's versatility can be seen in the entertainment world as well. The software has been used in animations for everything from music videos to movies, and even commercials.

And, completing a circle that began with the company's Interactive Physics software, Working Model has invaded the educational arena. Schools like Stanford, the University of Michigan, Cornell, and Georgia Tech have installed Working Model in large computer labs and are integrating motion analysis into the curriculum. In fact, a student edition of the software was recently released in college bookstores across the country.

Knowledge Revolution claims that about 15 to 20% of Working Model inquiries come from word-of-mouth. "We were pleasantly surprised by the response and the diversity of uses for the product," says Buszucki. "It's definitely what we hoped for."

So what can we expect from Knowledge Revolution in the future? Exactly what its customers have been asking for, says Goettner. This summer look for two major announcements from the company: A new release of Working Model with a scripting language and even more improvements in ease-of-use, and a 3-D version of the product.


Best New Product of the Year Contest

Last summer we asked OEM suppliers to enter their most outstanding products in the Design News Best New Product of the Year Contest. Companies filled out a detailed entry form to nominate their significant products introduced since September 1993.

Design News technical editors, the best entries were submitted to a panel of outside judges. The judges, in turn, selected a top product in each of seven categories: electrical/electronic; power transmission and motion control; fluid power; computer productivity tools; testing and instrumentation; fastening, joining, and assembly; and materials.

Our December 5, 1994 issue featured descriptions of these top products, and Design News readers voted by FAX for the single best product of the year. In addition, a drawing was held of all ballots received, with one of our readers winning a 32-inch Zenith color TV. Congratulations to the winner, Enrico Napoletano of Syntrex Technologies Inc., New York, NY.

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