Coordinates Of Contact Points Research Articles

Determination of contact points between workpiece and fixture elements as a tool for augmented reality in fixture design

Fixtures play a significant role in ensuring the quality of products in manufacturing engineering. The paper considers fork-type parts that have a complex spatial configuration and needs to be machined by drilling-milling-boring equipment in one setup. In fixture design, it is necessary to provide wide tool accessibility, and therefore the choice of locating surfaces of the workpiece is an important step. The mathematical approach for determining the coordinates of contact points between the workpiece and the locating and clamping elements fixtures in the coordinate system is developed in this paper. The geometric parameters of the workpiece are taken into account in determining the coordinates. It allows to apply the proposed approach for parts of another standard size, but the same design and technological features. The technology of augmented reality is an effective tool at the design stage of fixtures and allows to visualize the developed fixture configurations. This approach has been successfully applied for such parts as levers, connecting rods, flat parts.

Automatic Grasping of Objects by a Manipulator Equipped with a Multifinger Hand

We consider the problem of controlling a manipulator during the operation of the automatic grasping of a noncooperative object. The manipulator is equipped with a gripper in the form of a multifinger hand. The solution of the problem includes the planning and execution stages. When planning, the coordinates of contact points on the surface of the object, along with the coordinates of the manipulator and the fingers of the hand at the instant of a grasping are determined. When executing, the manipulator and the hand move from the initial position into the planned position.

Some features of the design and technological preparation of the production of spur gears with spatially modified teeth

Abstract The article presents the method of calculating the source data for the design and technological preparation of the production of cylindrical wheels with spatially modified gear rims. The dependences obtained allow us to determine the coordinates of contact points on the lateral surface of a spatially modified tooth. The data obtained in this way can be used to construct three-dimensional models of products with spatially modified gear rims, determining the geometry of the cutting part of the tool, determining the trajectory of the relative movement of the tool and the work-piece and controlling products with gear rims with spatial geometry.

Image analysis of axisymmetric droplets in wetting experiments: A new tool for the study of 3D droplet geometry and droplet shape reconstruction

A new software tool is developed for droplet image analysis for the study of wetting of solid substrates. The tool extracts information exclusively from images and does not require the use of any properties of the system. Moreover, its applicability covers both axisymmetric and non-axisymmetric droplets. The developed software processes independently droplet images taken from side and top perspectives. Processing of side-view images is made by polynomial fitting to the droplet shape and provides important 2D geometrical features such as contact angles, length, height, contact point coordinates and contour outline. The analysis of top-view images is achieved through active contours (snakes) and yields droplet dimensions, centroid position and contour outline. The combination of synchronized side and top images provides the reconstruction of the droplet 3D shape by means of slices of circular arc shape, which allows estimation of droplet volume and of the distribution of contact angles along its perimeter. The above is an important feature that has not been delivered by other software tools. Experimental results to support the applicability of the new tool are presented for two distinct substrates having different surface properties (glass and Teflon).

Tool Path Generation for Turbine Blades Machining With Twin Tool

Blades are essential parts used in thermal and nuclear power generation. Its machining precision is a vital factor that influences the efficiency and life of those industries. Blades are thin-walled parts, which could easily deform under cutting forces, and hence deteriorate the machining precision. In our previous work, a milling process with twin tool for blade is proposed, in which two tools are assigned to machine the basin and dorsal surfaces simultaneously. It is expected that the cutting forces acted on the basin and dorsal surfaces can be counteracted to reduce the deformation of the blade. In this study, a method of twin-tool paths generation is developed. The tool center points and tool axis vectors are generated with consideration of the cutting forces balance, the machine tool kinematics, the surface geometric precision, and the same number of tool paths on basin and dorsal surfaces. Virtual machining, finite element analysis, and trial cutting are carried out and verified that the method which is used for generating the twin-tool paths is successful. The basin and dorsal surfaces have the same number of tool paths and tool contact point coordinates, which guarantees that the two surfaces can be completely machined and can be machined and finished simultaneously. Furthermore, the cutting forces acted on the basin and dorsal surfaces can achieve the balance along the twin-tool paths. Therefore, the deformation of a blade caused by cutting force is obviously reduced compared with a conventional machining process with a single tool.

Determination of Motion Parameters for Rod Toothed Gears with Skew Axes

В работе рассматриваются приближенные передачи. Данная работа посвящена определению параметров движения зубчато-поводковой передачи на скрещивающихся осях. Разработка защищена патентом РФ. В статье обоснована актуальность синтеза новых видов зацепления с упрощенной геометрией контактирующих тел. Представлено расположение систем координат, использованных для получения функции положения передачи, состоящей из двух колес и неподвижного звена (стойки). Для передач на скрещивающихся осях получены координаты точек контакта на поверхностях поводков и рассчитаны ошибки функции положения при пересопряжении. Функция положения получена применением метода матричного преобразования систем координат и равенства радиусов-векторов и ортов нормалей в точке контакта. Данная передача может быть актуальна в машиностроении, приборостроении и других отраслях народного хозяйства. На ее основе могут быть синтезированы как редукторы, так и мультипликаторы. Она обладает высокой технологичностью (для ее изготовления не требуется специального оборудования), а функция перемещения близка к линейной. Данная статья характеризует влияние изменения передаточного отношения на качественные характеристики передачи. Определены минимальные допустимые передаточные отношения для различных чисел поводков ведущего колеса. Значения минимальных допустимых передаточных отношений существенно меньше, чем для конических зубчато-поводковых передач на пересекающихся ортогональных осях. Зацепление происходит без выхода точки контакта на кромку поводка. Для решения полученной системы уравнений применялись численные методы программного пакета MathCAD. В дальнейшем автором предполагается рассмотреть возможные погрешности монтажа и изготовления зубчато-поводковой передачи (такие, как погрешность шага, несоосность и т. д.) с целью оценки их влияния на качественные характеристики зацепления для всех типов взаимного расположения осей.

The effect of geometrical parameters of hypoid and spiroid gears on its quality characteristics

The orthogonal hypoid and spiroid gears are here considered. The point of tangency of the pitch cones is presumed to be simultaneously the calculation contact point of the teeth surfaces. Analytical relationships for the geometrical parameters and important quality characteristics depending on the contact point coordinates are given. These analytical relationships show that there is a possibility of varying the independent geometrical parameters within permissible limits. Because of this, it is shown that a pair of pitch cones with the best quality characteristics may be found.