Petri nets are applied to the bottom-up design of a handshaking protocol for transferring parts through a sequence of workstations. The authors illustrate the application of Petri-net theory to verify properties of th...
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Petri nets are applied to the bottom-up design of a handshaking protocol for transferring parts through a sequence of workstations. The authors illustrate the application of Petri-net theory to verify properties of the complete system behavior based on the structure of the Petri-net model. It is shown that communication between local controllers is modeled by places corresponding to upstream and downstream messages. Consistency in the interconnection of the subsystem models is guaranteed by the identification of these communication places. To analyze the properties of the complete system, results on liveness and place invariants for Petri nets are applied to the Petri-net model.< >
The equations of motion for a robotic manipulator are a very lengthy and complicated set of nonlinear, highly coupled differential equations. A simplified model that reveals the dominant dynamics would be valuable for...
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The equations of motion for a robotic manipulator are a very lengthy and complicated set of nonlinear, highly coupled differential equations. A simplified model that reveals the dominant dynamics would be valuable for purposes of utilizing modern control theory. In this work, a method is presented for obtaining a reduced model for a nonlinear system. The structure of the simplified model is assembled from a library of the nonlinear basis terms that were present in the original model. This p-term structure is selected from the library in p-stages using a recently developed optimization scheme based on projection matrices and conjugate direction ideas. The algorithm is used to identify the dominant dynamics of several robot manipulator models and the results are verified on the GCA P300V robot in RPI's Robotics and Automation Laboratory.
作者：
RAINS, DASTILES, HRHO, SPKDr. Dean A. Rains
Director of Advanced Programs and IRBD. Ingalls Shipbuilding Division Litton Industries Pascagoula Miss. has been an active member of ASNE since 1970. a frequent contributor to the Naval Engineers Journal and a participant at ASNE Day meetings as both an Author and a Discusser. He is an Associate Fellow of the American Institute of Aeronautics has twenty-three years experience in the field of Naval Engineering and is a graduate of the California Institute of Technology from which he received his B.S. degree (1950) and his M.S. degree (1952). both in Mechanical Engineering. and his Ph.D. degree (1954) in Mechanical Engineering and Mathematics. Mr. H. Richard Stiles graduated from the U.S. Naval Academy in 1965. Prior to leaving the naval service in 1970
he was designated as a Naval Aviator and authored two Patents one for an aircraft optical glide slope reference system and the second for an intercommunications system for air traffic control. As an author he has had technical papers published by SNAME — “Planning Hull Structure” — and by the Offshore Technology Conference — “A Fourth Generation Crewboat.” At the present time he serves as an Engineering Specialist for the Hull Technical Department at Ingalls Shipbuilding Division. Mr. Stephen P.K. Ho is also with Ingalls Shipbuilding Division where
since 1970 he has worked on various phases of naval engineering and advanced studies. He received both his B.S. and M.S. degrees in Naval Architecture and Marine Engineering from the University of Michigan in 1958 and 1959 respectively. and prior to joining Ingalls Shipbuilding Division also worked with other Marine Firms in ship design particularly in computer applications to Preliminary Design the Construction Process and the Management Information System. Besides ASNE which he joined in January 1980. he is a member of SNAME.
Lower Fleet operating costs and independence from foreign fossil fuel resources are the goals of energy conservation efforts for Navy surface ship. This paper describes an evaluation of a wide variety of energy conser...
Lower Fleet operating costs and independence from foreign fossil fuel resources are the goals of energy conservation efforts for Navy surface ship. This paper describes an evaluation of a wide variety of energy conservation approaches. A standard 20-knot, 300-hour Destroyer mission is established so that all of the approaches can be compared on a total fuel required basis. The approaches studied include use of aluminum hull construction; light weight machinery; trail-shaft or cross-connect operation for twin screw ships; improved performance propulsors; advanced power plant types, such as COGAS or cruise engines; use of energy storage techniques to improve ship service generator performance; electrical load reductions; improved performance ship service generators; hull drag reductions; crew size reductions; design margin reduction; reduced performance requirement (such as top speed); and habitability standard reductions. The overall results can be effected by reductions in range requirements as well. Mission duration was held constant at 45 days throughout the study. The results of the study indicate that the combination of these various possible improvements may reduce the fuel used to be as low as one-third of the current levels. Weight reductions are very effective for achieving significant fuel savings.
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