268 research outputs found

    Reliability Assessment of a Packaging Automatic Machine by Accelerated Life Testing Approach

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    Industrial competitiveness in innovation, the time of the market introduction of new machines and the level of reliability requested implies that the strategies for the development of products must be more and more efficient. In particular, researchers and practitioners are looking for methods to evaluate the reliability, as cheap as possible, knowing that systems are more and more reliable. This paper presents a reliability assessment procedure applied to a mechanical component of an automatic machine for packaging using the accelerated test approach. The general log-linear (GLL) model is combined based on a relationship between a number strains, in particular mechanical and time based. The complete Accelerated Life Testing - ALT approach is presented by using Weibull distribution and Maximum Likelihood verifying method. A test plan is proposed to estimate the unknown parameters of accelerated life models. Using the proposed ALT model, the reliability function of the component is evaluated and then compared with data from the field collected by customers referring to 8 years of real work on a fleet of automatic packaging machines. The results confirm that the assessment method through ALT is effective for lifetime prediction with shorter test times, and for the same reason it can improve the design process of automatic packaging machines

    A Supporting Decision Tool for the Integrated Planning of a Logistic Network

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    none4Design, management and control of a logistic distribution system are very critical issues in supply chain management. They involve a large number of interdependent decisions, such as the determination of the best location and capacity of a distribution center (DC), a production plant, a wholesaler etc., the allocation of customer demand to suppliers, e.g. regional DC (RDC), the adoption of a transportation mode, e.g. rail and truck, the vehicles routing adopting/not adopting a groupage strategy. This chapter presents an original and automatic supporting decisions platform for the integration of strategic (long-term), tactical (mid-term) and operational (short-term) decisions in the design, management and control of a logistic network including up to four operating levels: sources (production plants), central distribution centers (CDCs), RDCs, and customers. A case study is illustrated and obtained results discussed in presence of different problem settings and operating hypotheses.openMANZINI R.; BORTOLINI M.; GAMBERI M.; MONTECCHI M.MANZINI R.; BORTOLINI M.; GAMBERI M.; MONTECCHI M

    Automatic assessment of the ergonomic risk for manual manufacturing and assembly activities through optical motion capture technology

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    Abstract Safeguard the operator health is nowadays a hot topic for most of the companies whose production process relies on manual manufacturing and assembly activities. European legislations, national regulations and international standards force the companies to assess the risk of musculoskeletal disorders of operators while they are performing manual tasks. Furthermore, international corporates typically require their partners to adopt and implement particular indices and procedures to assess the ergonomic risks specific of their industrial sector. The expertise and time required by the ergonomic assessment activity compels the companies to huge financial, human and technological investments. An original Motion Analysis System (MAS) is developed to facilitate the evaluation of most of the ergonomic indices traditionally adopted by manufacturing firms. The MAS exploits a network of marker-less depth cameras to track and record the operator movements and postures during the performed tasks. The big volume of data provided by this motion capture technology is employed by the MAS to automatically and quantitatively assesses the risk of musculoskeletal disorders over the entire task duration and for each body part. The developed hardware/software architecture is tested and validated with a real industrial case study of a car manufacturer which adopts the European Assembly Worksheet (EAWS) to assess the ergonomic risk of its assembly line operators. The results suggest how the MAS is a powerful architecture compared to other motion capture solutions. Indeed, this technology accurately assesses the operator movements and his joint absolute position in the assembly station 3D layout. Finally, the MAS automatically and quantitatively fill out the different EAWS sections, traditionally evaluated through time- and resource-consuming activities

    Integration of single and dual command operations in non-traditional warehouse design

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    Abstract Non-traditional warehouses rise as effective solutions to shorten the travelled distances to store and retrieve unit loads, adding aisles crossing the parallel racks. Multiple warehouse configurations are proposed by the literature discussing the enhancements toward standard layouts. In previous contributions, the authors introduced the diagonal cross-aisle model, concluding about its positive impact on the handling performances under single command operations. This paper extends the previous works, integrating dual command operations, through an original analytic model supporting the design of non-traditional warehouses with a couple of symmetric straight diagonal cross-aisles and random storage assignment strategy. The closed-form expressions to compute the expected cycle travel distances are provided, optimising the aisle position. An industrial case study applies the model, getting distance savings ranging from 11 to 17%, compared to standard layout and further considering the loss of storage space due to the presence of the additional aisles

    Corrigendum: Corrigendum to 'Learning manual assembly through real-time motion capture for operator training with augmented reality"

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    Abstract The authors regret that The authors would like to apologise for any inconvenience caused

    real time assistance to manual assembly through depth camera and visual feedback

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    Abstract The current fourth industrial revolution significantly impacts on production processes. The personalized production paradigm enables customers to order unique products. The operators assemble an enormous component variety adapting their process from product to product with limited learning opportunities. Digital technologies are increasingly adopted in production processes to improve performance and quality. Considering this framework, this research proposes a hardware/software architecture to assist in real-time operators involved in manual assembly processes. A depth camera captures human motions in relation with the workstation environment whereas a visual feedback guides the operator through consecutive assembly tasks. An industrial case study validates the architecture

    Optimal Operations Management of Hybrid Energy Systems Through Short-Term Atmospheric and Demand Forecasts

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    Abstract The complexity of systems for energy production through renewable energy sources (RESs) is constantly increasing considering the integration of multiple modules, e.g. different RES sources, energy storage in batteries and connection to national grid for energy trade purpose. This significant complexity could represent a threat but also an opportunity if adequately managed. Aim of this paper is to propose two different approaches to manage the hourly electricity flows between the different components of a hybrid energy system (HES) fueled by PV modules and a wind turbine, equipped with a battery storage system (BES) to satisfy the demand of a user load with the opportunity to sell and purchase the electricity to/from the national grid. The first approach is a heuristic algorithm (HA) which defines robust but constant dispatching criteria of the energy flows between the HES components considering just the current value of energy production and demand with the aim of minimizing the electricity purchased by the grid. On the contrary, the second approach is a mixed integer linear programing (MILP) model which defines the optimal value of the energy flows to maximize the net profit of the HES operations determined by the electricity sales revenues minus the energy purchase costs. The developed MILP leverages the short-term forecast of the atmospheric conditions and user demand as well it considers variable energy sale and purchase pricing in the different daily hours. Both these approaches have been tested and validated through a case study of a residential building in which multiple households live located in the suburban area of Munich (Germany). The obtained results highlight how the MILP outperforms HA considering the net profit achievable weekly due to electricity trade with the grid. In particular, the MILP improve the HA economic performance of the HES operation management of 18% on average over the different months of the year

    GEOSTAR, an observatory for deep sea geophysical and oceanographic researches: characteristics, first scientific mission and future activity

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    GEOSTAR (GEophysical and Oceanographic STation for Abyssal Research) is a project funded by in the 4th Framework Programme of the European Commission, with the aim of developing an innovative deep sea benthic observatory capable of carrying out long-term (up to 1 year) scientific observations at abyssal depths. The configuration of the observatory, conceived to be a node of monitoring networks, is made up of two main subsystems: the Bottom Station, which in addition to the acquisition and power systems and all the sensors also hosts the communications systems; and the Mobile Docker, a dedicated tool for surface-assisted deployment and recovery. At present the Bottom Station is equipped with a triaxial broad-band seismometer, two magnetometers (fluxgate and scalar), CTD, transmissometer, ADCP, but it can easily host other sensors for different experiments. The first phase of the project, started in November 1995, was concluded with the demonstration mission in Adriatic Sea at shallow water depth (42 m) in August - September 1998. Some preliminary results of this first scientific experiment are presented and discussed. The second phase, started in 1999, will end with a long-term deep sea scientific mission, scheduled during 2000 for 6-8 months at 3400 m.w.d. in the southern Tyrrhenian bathyal plain.Published491-4973A. Ambiente MarinoN/A or not JCRrestricte
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