A new algorithm to measure the straightness of a machine tool and that of a machined work is proposed. This makes it possible to investigate the correlation of the two. The case of an engine lathe is used as an example. The measurement is performed by sensing the relative displacement between the objective and the tool post which carries two sensors and is fed with steps of distance. The machine tool characteristics have the most important effect on the machined work. The method can be extensively applied to measuring the cylindricity.
BackgroundLeukoaraiosis is defined as extracellular space caused mainly by atherosclerotic or demyelinated changes in the brain tissue and is commonly found in the brains of healthy older people. A significant association between leukoaraiosis and traffic crashes was reported in our previous study; however, the reason for this is still unclear.MethodThis paper presents a comprehensive evaluation of driving performance in ordinary older drivers with leukoaraiosis. First, the degree of leukoaraiosis was examined in 33 participants, who underwent an actual-vehicle driving examination on a standard driving course, and a driver skill rating was also collected while the driver carried out a paced auditory serial addition test, which is a calculating task given verbally. At the same time, a steering entropy method was used to estimate steering operation performance.ResultsThe experimental results indicated that a normal older driver with leukoaraiosis was readily affected by external disturbances and made more operation errors and steered less smoothly than one without leukoaraiosis during driving; at the same time, their steering skill significantly deteriorated.ConclusionsLeukoaraiosis worsens the driving performance of older drivers because of their increased vulnerability to distraction.
Investigations were made on self-excited chatter of the work which is held at one end on a lathe machine. Analysis was carried out by a two-degrees-of-freedom system. It was verified that introduction of the multiple regenerative effect governs the finite amplitude of the vibration after it is excited. It was also shown that behavior of the work displacement rotating around the origin during the vibration could be explained by taking into account a resistive force which is inversely proportional to the cutting speed and is proportional to the velocity of the vibration. Phase difference of the vibration occurring for each turn of the work was measured by making use of a microcomputer system. Correlation of the pattern left on the work with the phase difference and with the multiple regenerative effect was studied. A slight change of the vibration frequency varies the pattern even though the phase difference is kept constant. This was also demonstrated by a simulation which generated the pattern of surface shape.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.