June 2009

Potential of state-feedback control for machine tools drives

MM (Modern Machinery) Science Journal, June 2009
L. Novotny1, P. Strakos1, J. Vesely1, A. Dietmair2,
1Research Center of Manufacturing Technology, CTU in Prague, Czech Republic,2SW, Universität Stuttgart, Germany
Abstract

This paper describes basic principle of the state feedback control technique and its potential for the feed drive control in the machine tool domain. It evaluates the quality of the state control and compares it with the traditional cascade control. The emphasis is put on an estimation of the state variables using an FEM model of the feed drive mechanical structure and machine frame.

Keywords: Machine tools, drives and control, state – feedback control, state estimation
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Computer modelling of suction cups used for window cleaning robot and automatic handling of glass sheets

MM (Modern Machinery) Science Journal, June 2009
Fr. Novotny, M. Horak
Department of Glass Producing Machines and Robotics, Technical University of Liberec, Czech Republic
Abstract

Optimizing vacuum grippers of robots for glass sheets handling and developing robots for glass cleaning, it is necessary to solve a number of problems calling for a similar approach to a solution. This paper analyzes deformation behaviour of vacuum gripping elements of vacuum grippers. The extent of deformation safety of an individual suction cup is monitored depending on the vacuum level and loading character. A computer model was suggested and filtered out allowing contact area changes to be observed depending on a friction model and vacuum level.

Keywords: vacuum robot gripper, suction cup, window cleaning robot, mobile platform
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Contribution to the production flexibility solution

MM (Modern Machinery) Science Journal, June 2009
D. Kumicakova, I. Kuric
Department of Automation and Production Systems, University of Zilina, Slovak Republic
Abstract

Production (manufacturing) flexibility is one of the dominant requirements of the present engineering industry. Automated assembly systems have a special position because of their technical and technological complexity. At the present the problem of determination of existing or planned assembly systems flexibility is elaborating at the many research workplaces. The attention is focused on to elaborating of the base methodical steps for determination of a relative similarity of objects group (assembly parts and assembly grippers) with suitable statistical methods utilisation. The dichotomous parameters were defined for the objects similarity valuation.

Keywords: flexibility, automation, assembly gripper, similarity, clusters analysis
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Effects of microstructure and chemical composition on strength and impact toughness of tin bronzes

MM (Modern Machinery) Science Journal, June 2009
J. Audy
Edith Cowan University, School of Enterprise and Technology, Bunbury, Australia
Abstract

The present study is concerned with examining metallurgical features and their significance on strength and impact toughness of tin bronzes, with particular reference to bells. It has embraced a number of interrelated aspects – alloy types – composition, constitution and properties, fabrication technology, service life and effects of environmental/working conditions on strength and impact toughness of bell materials from Gothic, Modern and Recent Eras. The results are discussed in terms of qualitative assessment of microstructural features of these different cast tin bronzes examined in destructive tests.

Keywords: Tin Bronzes, Microstructure, Chemical Composition, Strength and Impact Toughness
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