Degradation of dissimilar metal welds in the piping systems of power plants is recognized as a significant ageing factor. Hence, close scientific attention is paid to various degradation mechanisms concerned with dissimilar metal welds, as well as to welding metallurgy. However, the process of dissimilar metal weld refurbishment consisting of the weld groove machining and subsequent repair welding is based on obsolete methods. Particularly, the machining stage has to rely on conventional portable machining or, more often, on manual grinding. Neither of these methods is adequate, especially when it comes to the special environment of the nuclear power plants. In this article, a novel design of an automatic orbital milling system intended for machining degraded welds in piping systems is presented. The system incorporates an orbital milling head designed to enable machining within the limited space, combined with a microcontroller-based control system providing full control over the geometry of the weld groove. Thus, the degraded dissimilar metal weld is removed, and simultaneously, the weld groove of desired geometry is prepared rapidly and flexibly, without the need for customized profile cutters, being the main contribution of the proposed design. The system prototype was verified by implementation in the Bohunice V2 nuclear power plant.
This paper presents the collision-free operation of a robotic arm mounted on a mobile robotic unit, using the MS Windows Kinect 3D optical system. The 3D optical system is used for measuring distances and aiding the collision-free manipulation of objects by means of the robotic arm installed on the mobile robotic system (MRS). Attaching of the optical system directly to the robotic arm, essentially, ensures the autonomy of the overall system. The MRS is capable of recognizing the predefined objects in the three-dimensional space as well as automatically approaching and manipulating them using the robotic arm. The aim of this article is to present the algorithms used in the MRS to guarantee the collision-free operation of the system. The novelty of our approach lies in the a priori collision avoidance strategy instead of solving collision states as they occur. In addition, the article presents the problem of the localization of the objects in the robot's surrounding. For this purpose, the balls randomly placed on the floor were localized by the MRS, estimating their real coordinates. Instead of using the standard RGB color space, we propose to utilize the HSV color space in order to enhance the process of objects recognition since the HSV color space provides the more consistent results in the case of varying intensity of the ambient light.
AbstraktPríspevok sa zaoberá bezkolíznou manipuláciou ramena mobilného robota s využitím 3D optického kamerového systému MS Windows Kinect. 3D optický systém slúži pre potreby merania vzdialeností a následnou bezkolíznou manipuláciou s nimi na použitom mobilnom robotickom systéme (MRS), zaujímave je jeho konštrukčné umiestnenie priamo na ramene robota pre zachovanie autómnosti celého systemu. MRS je technologický mobilný robotický demonštrátor, kompletne vyvinutý na našom pracovisku a jeho úlohou je oboznámiť študentov a odbornú verejnosť s možnosťami súčasnej mobilnej robotiky. MRS dokáže rozpoznávať v priestore vopred zadefinované objekty priblížiť sa autonómne k nim a za pomoci robotického ramena bezkolízie aj s nimi
The paper deals with the problem of object recognition for the needs of mobile robotic systems (MRS). The emphasis was placed on the segmentation of an in-depth image and noise filtration. MS Kinect was used to evaluate the potential of object location taking advantage of the indepth image. This tool, being an affordable alternative to expensive devices based on 3D laser scanning, was deployed in series of experiments focused on object location in its field of vision. In our case, balls with fixed diameter were used as objects for 3D location.
AbstraktPríspevok sa zaoberá problémom rozoznávania objektov pre potreby mobilnej robotiky a bol vypracovaný s dôrazom na hĺbkový obraz pri segmentácii a filtrácii rušivých informácií. Pre posúdenie potenciálu hľadania objektu na hĺbkovom obrázku bol použitý MS Kinect, nakoľko je to lacná alternatíva k drahým laserovým 3D snímačom. Za pomoci neho boli vykonane experimenty orientované na vyhľadávanie objektov v jeho zornom poli. V konkrétnom prípade riešeného v tomto príspevku sa jedná o loptičky s pevne stanoveným priemerom.
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