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By Gary Chamberlain, Senior Editor -- Design News, April 5, 1999
Robots that think on their feet closer to reality
A robot on the factory floor usually is stuck with its scripted mode of operation amidst what could become an ever-changing landscape. As a result, it more than likely would keep spot welding, for instance, on a non-existent automobile frame caused by a delay on the assembly line. Now, an engineer at Washington University in St. Louis and two of his former graduate students have come up with a theory and devised an algorithm that could make such robots more deft and nimble. The theory, demonstrated with robots at the University's lab, integrates low-level data sensing with high-level planning and decision-making processes. The demonstrators include: T.J. Tarn, professor of systems science and mathematics in the University's School of Engineering and Applied Science; Mumin Song, technical specialist with Ford Motor Co. in Detroit; and Ning Xi, assistant professor of electrical engineering at Michigan State University. "What the model does is enable the robot to stop and think," explains Song. "Stopping is the key. It gives the machine time to 'think,' then feed data back to the upper level." The algorithm, called Max-Plus Algebra Model, combines task-scheduling, action-planning, and control without human intervention. Air-traffic control is another possible application, says Tarn. E-mail tony_fitzpatrick@aismail.wustl.edu.
Ceramic parts that 'grow before your eyes'
An engineer at Sandia National Laboratories has found a way to fabricate ceramics that requires no molds or machining. Called robocasting, the technology relies on robotics for computer-controlled deposition of ceramic slurries--mixtures of ceramic powder, water, and trace amounts of chemical modifiers--through a syringe. The material, which flows like a milkshake even though the water content measures only about 15%, is deposited in thin sequential layers onto a heated base. "Layer by layer the part grows before your eyes," says Joe Cesarano, the engineer who originated the concept. "The robot squeezes the slurry out of the syringe, almost like a cake decorator, following a pattern prescribed by computer software." Because Cesarano's method allows a dense ceramic part to be free-formed, dried, and baked in less than 24 hours, it makes a perfect prototyping material, Cesarano feels. More traditional ceramic fabrication may take weeks to go from a design to an actual part. For instance, the standard dry pressing method requires ceramic powder to be compacted into a billet. To make a complicated part, the billet must be sculpted into the final shape with costly machines. Cesarano is working with one company to prototype a ceramic part for use in fabricating fiber optics for advanced x-ray diffraction applications. E-mail jcesara@sandia.gov.
Planet-friendly plastics would decompose harmlessly
In the spring, ski slopes often are littered with plastic lift tickets that won't decay. That could change, providing the tickets consist of biodegradable plastic developed by Mrinal Bhattacharya, professor of biosystems and agricultural engineering, and his colleagues at the University of Minnesota. The researchers use protein found in cereal grains, along with plant starch, to make the plastic. In Bhattacharya's lab you will find golf tees, forks, spoons, and doggie chew bones made from the material. Colleague Kim Stelson, a professor in the Dept. of Mechanical Engineering, describes the starch-based plastic as a reacted blend of starch and synthetic polymers. "Starch-based plastics are recyclable and biodegradable, reducing the environmental impact, and they can be made cheaper than other plastics," Stelson adds. The starch used to create the biodegradable plastic--typically wheat gluten--costs about 15 cents a pound. Today's lowest-price commodity plastics cost about $1 a pound, and their environment-friendly counterparts cost about $2.50 a pound. The Minnesota team says its plastic now costs about $1.50 a pound. E-mail bhatt002@tc.umn.edu.
Steel industry forms consortium to develop advanced vehicles
Representatives of the world steel industry recently gathered in Detroit to convene the inaugural meeting of a consortium formed to oversee an ambitious two-year automotive design and engineering program. The goal: "significantly broaden the ULSAB (UltraLight Steel Auto Body) series of initiatives." The program, ULSAB-AVC (Advanced Vehicle Concepts), will take a holistic approach to the development of a new, advanced steel automotive vehicle architecture. The scope of the program will "go beyond the body-in-white to include closures, suspensions, engine cradle, and all structural and safety relevant components." A comprehensive benchmarking of existing vehicle concepts and an investigation of trends in vehicle development will kick off the program. Targets will be set with reference to the U.S. PNGV (Partnership for a New Generation of Vehicles) and EUCAR (European CO2 reduction program) projects. The consortium consists of 26 steel-producing companies from around the world. E-mail martind@autosteel.org.
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