Modelling of assembly sequences using hypergraph and directed graph

Rad se bavi problemom modeliranja tehnološkog procesa montaže proizvoda s posebnim naglaskom na sekvence kod povezivanja dijelova i cjelina. U radu se predstavljaju najvažniji parametri modeliranja sekvenci montaže, uključujući osnove heuristčkog postupka kojim bi se trebalo pojednostavniti pronalaženje racionalne varijante. Predložena metoda određivanja sekvenci montaže dijelova i cjelina strojeva primjenom hipergrafova i usmjerenih grafova sastoji se od: izbora glavnog osnovnog dijela i osnovnih dijelova pojedinih jedinica montaže, bilježenja strukture konstrukcije jedinice montaže u obliku usmjerenog hipergrafa i minimiziranja broja njegovih rubova do oblika digrafa, bilježenja matrice strukture konstrukcije jedinice montaže u obliku matrice stanja i matrice grafa, izbora ekstremne putanje u digrafu. Važan element rada je detaljni algoritam određivanja sekvenci montaže primjenom matrice hipergrafa i usmjerenog grafa, matrice stanja i grafa koji je primijenjen na računalnom softveru "Msassembly".The work concerns the problem of modelling technological process of product assembly, with particular stress on the sequences of connecting its parts and units. The work presents the most important parameters of modelling assembly sequences, including the bases of heuristic proceeding which has to simplify finding its rational variation. Suggested method of determining the sequences of assembly of parts and units of machines using hypergraphs and directed graphs consists of: selection of the main base part and base parts of particular assembly units, recording of construction structure of assembly unit in the form of directed hypergraph and minimization of the number of its edges to the form of digraph, matrix recording of construction structure of assembly unit in the form of state matrix and graph matrix, the selection of extreme path in digraph. An important element of the work is a detailed algorithm of determination of assembly sequences using the matrix of hypergraph and directed graph, state matrix and the graph which was implemented to computer software "Msassembly"

No Clamp Robotic Assembly with Use of Point Cloud Data from Low-Cost Triangulation Scanner

The paper shows the clamp-less assembly idea as a very important one in the modern assembly. Assembly equipment such as clamps represent a significant group of industrial equipment in manufacturing plants whose number can be effectively reduced. The article presents the concept of using industrial robot equipped with a triangulation scanner in the assembly process in order to minimize the number of clamps that hold the units in a particular position in space. It also shows how the system searches for objects in the point cloud based on multi-step processing algorithm proposed in this work, then picks them up, transports and positions them in the right assembly locations with the use of industrial robot manipulator. The accuracy of the positioning of parts was also examined as well as the impact of the number of iterations of the algorithm searching the models in the point cloud on the accuracy of determining the position of the objects. The tests show that presented system is suitable for assembly of various items as plastic packaging and palletizing of products. Such kind of system is the basis for modern, fully flexible assembly systems

Assembly Sequence Planning Using Artificial Neural Networks for Mechanical Parts Based on Selected Criteria

The proposed model of the neural network describes the task of planning the assembly sequence on the basis of predicting the optimal assembly time of mechanical parts. In the proposed neural approach, the k-means clustering algorithm is used. In order to find the most effective network, 10,000 network models were made using various training methods, including the steepest descent method, the conjugate gradients method, and Broyden–Fletcher–Goldfarb–Shanno algorithm. Changes to network parameters also included the following activation functions: linear, logistic, tanh, exponential, and sine. The simulation results suggest that the neural predictor would be used as a predictor for the assembly sequence planning system. This paper discusses a new modeling scheme known as artificial neural networks, taking into account selected criteria for the evaluation of assembly sequences based on data that can be automatically downloaded from CAx systems

Selection of methods used for analyzing the standard time needed to complete the assembly process by means of a fuzzy analytic hierarchy process

This paper is a review of four main methods of analyzing the standard time needed to complete a given job: chronometric analysis, working-day activity study (working-day photo), work sampling observations, and analysis of basic motions. Thanks to the application of FAHP (Fuzzy Analytic Hierarchy Process) method, the values of weighted coefficients were obtained which describe the importance of selecting the criteria of the choice of methods used to analyze the standard time in the assembly process. In the summary paragraph of this paper, the results of analyzing the criteria are discussed

Ergonomic solutions to support forced static positions at work

The article analyzes the available ergonomic constructions used for the support of the musculoskeletal system during static, prolonged work performed in forced positions. Possible evaluation methods are presented as well as ergonomic considerations of work performed in inclined positions, where there is no possibility of influencing the working plane. As a result of the presented work, a set of criteria has been proposed and the requirements for methods which can be used to evaluate the technical constructions supporting the worker during tasks performed in forced and static positions

Selection of an industrial robot for assembly jobs using multi-criteria decision making methods

The paper proposes three multi-criteria decision-making (MCDM) methods for the selection of an industrial robot for a universal, flexible assembly station, taking into consideration the technical and performance parameters of the robot. Fuzzy versions of AHP and TOPSIS methods as well as SMART were chosen from the variety of MCDM methods as they represent different attitudes to analysis. In order to minimise the impact of the method applied on the final decision, a list of results of the analyses has been developed and a final classification has been made based on decision makers’ preferences concerning selected parameters of the robo

Selection of methods used for analyzing the standard time needed to complete the assembly process by means of a fuzzy analytic hierarchy process

This paper is a review of four main methods of analyzing the standard time needed to complete a given job: chronometric analysis, working-day activity study (working-day photo), work sampling observations, and analysis of basic motions. Thanks to the application of FAHP (Fuzzy Analytic Hierarchy Process) method, the values of weighted coefficients were obtained which describe the importance of selecting the criteria of the choice of methods used to analyze the standard time in the assembly process. In the summary paragraph of this paper, the results of analyzing the criteria are discussed

Wpływ cyfryzacji i przemysłu 4.0 na usprawnianie procesów produkcyjnych oraz ergonomię pracy

Terms such as Industry 4.0, Logistics 4.0, smart factory, smart logistics as well as digitalization can nowadays be regarded as keywords in both scientific and economic practice. What is taking place at the moment is the beginning of the fourth industrial revolution, which is driven by rapid technological advancements, especially visible in the field of digital transformation, autonomous machines or fully automated warehouses. Strong competition on the domestic and foreign market and growing customer expectations suggest that manufacturing companies should not only increase production on a constant basis, but they should find also a way to personalize it, which means manufacturing short series of products designed to meet the needs of specific customers, but also personalizing human work itself. In this system, or a kind of set-up, the role of the human and the consequent workload associated with a given job change. Technology is increasingly replacing not only physical human work, but also human beings as decision-makers. It is giving rise to completely new situations, in which it is necessary to search for new forms of cooperation between human beings and the technological/ environmental ones. This kind of production is the ultimate goal of the fourth industrial revolution. The purpose of this paper is to analyze the impact of digitalization and Industry 4.0 on the optimization of production processes, supply chain and human work. The authors discuss the concept of Industry 4.0, hence the fourth industrial revolution concerning system integration and networking. They present the assumptions of Logistics 4.0 and include adaptive, resource-efficient and user-friendly approaches, concepts. The authors also discuss the application of Lean management in the concept of Industry 4.0, and the ergonomic inclinations of the individual pillars of Industry 4.0. The conclusion summarizes the considerations on the impact of digitalization and Industry 4.0 on the improvement of production processes and work ergonomics.Pojęcia takie jak: Przemysł 4.0, Logistyka 4.0, smart factory, smart logistics oraz digitalizacja są aktualnie słowami kluczowymi zarówno w nauce, jak i w praktyce gospodarczej. Obecnie ma miejsce czwarta rewolucja przemysłowa, której początki obserwujemy i która jest napędzania przez gwałtowny rozwój technologiczny, szczególnie w zakresie transformacji cyfrowej, autonomicznych maszyn czy w pełni automatycznych magazynów. Silna konkurencja na rynku krajowym i zagranicznym i rosnące oczekiwania klientów sprawiają, że nie tylko należy nieustannie zwiększać produkcję, ale także znaleźć sposób na jej personalizację, czyli wytwarzanie krótkich serii wyrobów zaprojektowanych pod kątem potrzeb danego klienta, lecz i samej pracy człowieka. W tym systemie lub rodzaju konfiguracji rola człowieka, a co za tym idzie – obciążenie pracą związane z danym stanowiskiem, zmieniają się. Technologia coraz częściej zastępuje nie tylko pracę fizyczną człowieka, ale także samych ludzi jako decydentów. Daje początek zupełnie nowym sytuacjom, w których konieczne jest poszukiwanie nowych form współpracy między ludźmi a technologią i środowiskiem. To właśnie taka produkcja ma być efektem czwartej rewolucji przemysłowej. Celem artykułu jest przedstawienie wpływu digitalizacji i Przemysłu 4.0 na optymalizację procesu produkcji, łańcucha dostaw i pracy ludzkiej. Autorzy omawiają koncepcję Przemysłu 4.0, a więc czwartej rewolucji przemysłowej, dotyczącej integracji systemów i tworzenia sieci; przedstawiają założenia Logistyki 4.0 – podejścia, koncepcje adaptacyjne, zasobooszczędne i przyjazne dla użytkownika. Autorzy prezentują także zastosowania lean management w koncepcji Przemysłu 4.0 oraz ergonomiczne inklinacje poszczególnych filarów Przemysł 4.0. Zakończenie zawiera podsumowanie rozważań dotyczących wpływu cyfryzacji i Przemysłu 4.0 na usprawnianie procesów produkcyjnych oraz ergonomię pracy