Papers by Keyword: Measurement

Abstract: The paper aims to present some studies on the influence of mechanical braking systems with shoes on separately excited DC motors, intended to change the regime speeds. The researches were carried out by braking a 5 W DC motor with a maximum speed of 700 rpm, intended for special drives, with the help of a polyamide half-shoe brake, when measuring the variation of some process parameters: speed of the motor under the braking conditions, the temperature inside the shoe and the electrical parameters of the motor - voltage, current, power and energy consumed.

Abstract: Proposed a method for measuring parameters of micro-surface machine parts optoelectronic and computer facilities, based on the computation of two-dimensional settings of the autocorrelation function, based on the binary image of the investigated microrelief using kvazioptimalnogo correlation algorithm. Found to be the most informative characterization of the studied surfaces, micro precision components reliably distinguished from each other with a given probability, is the average amplitude of the variable component of the autocorrelation function. Shows the results of determining the parameters of microrelief surface of runner blade GTM using quasi-optimal correlation algorithms.

Abstract: Measurement of industrial parts is very important for current production. There are many different methods (contact and non – contact) for part ́s control. Every of those methods have some advantages and disadvantages. The biggest problem was found in measurement of very small parts or complex parts which have some inaccessible places. The solution was implementation of X-ray technology into the measuring process. It is called computed tomography or metrotomography (connecting metrology and tomography). This technology finds application in many different fields, especially in the automotive industry. The result of the method is cloud of points or generated STL models which are suitable for use in other software for evaluation. However, there is still question of the method accuracy and accuracy of the generated STL models. This paper is dealing with scanning of plastic part with X-ray technology, generating of STL models by different methods and their accuracy evaluation.

Abstract: Aerodynamics is a relatively young scientific discipline, which started developing in the 50´s of last century. There are known several methods for calculating and measuring of the aerodynamic variables – in-situ measurements, wind tunnel measurements, CFD simulations and calculations according to national standards. Each method has its advantages and disadvantages. Nowadays a large focus is on experimental verifying the findings achieved with calculations help and CFD simulations. One of the verification possibilities are measurements in wind tunnels. The submitted paper deals with construction and using of the wind tunnel by the Slovak University of Technology in Bratislava. This device was put into operation after experimental verification in 2012, so this wind tunnel is one of the newest of its kind in Europe. The concept of the construction of individual structural elements and the wind tunnel parts has been designed in collaboration with the Aeronautical Research and Test Institute (Czech Republic) and was based on previous made analysis of aerodynamic tunnels. Its structure was designed and realized by Konštrukta Industry (Slovak Republic). We could it characterized as atmospheric boundary layer wind tunnel with open test section. It is unique with two test sections – front and back measuring space, where the front measuring space is used for uniform flow and the back measuring space is used for turbulent flow. That is why it is not only usable in the civil engineering sector (buildings, bridges, chimneys etc.), but also in city urbanism (pedestrian wind comfort and wind safety, dispersion of air pollutants), aircraft and automotive industries.

Abstract: This article is oriented toward the heat-moisture behaviour of the wooden construction sheeting. The behaviour of building envelope is evaluated according to the heat transfer coefficient and foremost from the view of the condensed vapour amount inside the building envelope structure. For exemplary building envelope will be elaborated model calculations and then they will be compared. The results have shown that diffusion-open structure has the best characteristics concerning the heat-humidity behaviour and ecology of wooden constructions.

Abstract: The machining accuracy of parts depends greatly on the positioning accuracy and repeated positioning accuracy of the machine tools, which can be affected by the transmission backlash. Therefore, it is of great importance to measure and compensate the transmission reverse clearance of NC machine tools at regular intervals. This paper mainly studies how to eliminate the reverse clearance of NC machine tools.

Abstract: As part of moving towards a sustainable production of diesel engines for heavy vehicle applications, the ability to predict casting defects has become ever so important. In order to model the solidification process for cast components correctly, it is of essence to know how the material will actually behave. To produce sound castings, often of complex geometry, the industry relies on various simulation software for the prediction and avoidance of defects. Thermophysical properties, such as density, play an important part in these simulations.Previous measurements of how the volume of liquid grey iron changes with temperature has been made with a conventional dilatometer. Measurements have also been made in the austenitic range, then on iron-carbon-silicon alloys with a carbon content lower than 1.5 wt%. Based on these measurements the density variations during solidification were calculated. The scope for this paper is to model the volume changes during solidification with the control volume finite difference method, using data from the density measurements.

Abstract: Buckling Restrained Braces (BRB’s) have become common in seismic frames in earthquake areas. If a BRB performs as desired the steel core may yield but it is not easy to know the degree of yielding, or how much of the BRB earthquake life has been used up. To determine whether such a brace should remain as is, or whether it needs to be replaced, an inexpensive and simple measuring device that reports the deformations undergone is required. This paper discusses a study undertaken to develop such a device. Firstly, a literature study was undertaken and candidate devices were selected. Using Subjective Quantitative Analysis (SQA) and specific performance objectives the most appropriate of these was chosen. This device was then constructed and tested in a controlled environment. This mechanical device performed well through various stimulated earthquake cycles and events, is cheap, simple to install, and small. It provides cumulative and maximum displacement estimations and will be beneficial to the industry in post-event decision making.

Abstract: This report discusses how a transmission error curve is derived by a coordinate measuring machine, and the result by a coordinate measuring machine is compared with the result by a transmission error measuring machine. A vibration based on a gear pair engagement in fishing reel occurs when a handle of the reel rotates. When this vibration is large, an angler feels uncomfortable. In author’s previous reports, it is known that a rotational feeling depends on the transmission error curve. The result indicates that the rotational feeling can be improved if the accuracy of a tooth flank is improved. In order to reduce the transmission error, the error should be measured in high accuracy. In this research, a measurement method for evaluating the rotational feeling was reported using a face gear pair via a coordinate measuring machine and a transmission error measuring machine. As a result, it was confirmed that the result of measurement by the coordinate measuring machine agrees very well with the result of measurement by the transmission error measuring machine.

Abstract: According to problems in manufacturing and measuring process of cycloidal gear used in RV reducer, the profile coordinates of cycloidal gear captured by three coordinates measuring instrument Surveying and mapping do not coincide with the designed tooth profile coordinates in theory, it is difficult to precisely capture the addendum and dedendum of each cycloidal gear teeth, furthermore, the captured addendum and dedendum do not coincide with the actual tooth items. For these problems, this paper introduced a method can accurately calculating the manufacturing error of cycloidal gear.Based on the captured coordinate points of cycloidal gear tooth profile, firstly, find out 39 approximate addendums by calculating and comparing the radial radius of all points, divide the whole scanning points into 39 profile points groups by the 39 approximate addendums, with each group include a whole single tooth profile. Then, in each profile points group, interpolate the spline and precisely calculate the addendums and dedendums by fitting and recalculating radial radius.Set up the coordinate system of surveying and mapping profile by the 39 addendums. calibrate the coordinate system of surveying and mapping profile with the new coordinate system through coordinate transformation, calculate the radial runout error at top and root of tooth profile, pitch error, adjacent pitch error and accumulated pitch error as well as other manufacturing errors of the cycloidial gear at last.Through experiment, this process solve the problem in measuring process of cycloidal gear that the captured point by three coordinates measuring instrument could not be directly used for calculating the errors items.