Oblikovanje sustava komisioniranja s vertikalnim podiznim modulima

U početku rada dani su opis, definicija i podjela vertikalnih podiznih modula, njihov razvoj kroz povijest, glavne značajke i osnovni načini primjene. U nastavku slijedi pregled glavnih dijelova VLM-a, način izvršavanja funkcije, te okvirni dimenzijski i ostali tehnički podaci. Zatim su definirani benefiti i mane vertikalnih podiznih modula, kao i osnovni podaci o održavanju i instalaciji. Navedene su primjene vertikalnih podiznih modula u sustavima rukovanja materijalom, a kraj prvog dijela rada opisuje primjenu vertikalnih podiznih modula u sustavima skladištenja u Republici Hrvatskoj. U drugom dijelu rada prezentirani su razvijeni modeli protoka za sustave komisioniranja vertikalnim podiznim modulima i dostupan programski paket za oblikovanje sustava komisioniranja s vertikalnim podiznim modulima. U završnom dijelu rada dani su rezultati testiranja programa na različitim slučajevima uz variranje ulaznih parametar

Difference and similarity in perception between Green Supply Chain Management in food industry and Green Supply Chain Management in generally in Croatian companies

Nowadays, the increase in greenhouse gas (GHG) emissions in the atmosphere is currently one of the most serious environmental treats. Due to GHG emissions we will be witnesses of climate change which will cause damaging impacts in the next few decades [1]. These will primarily affect the natural and human systems [2]. At the same time these emissions are also a limiting factor for the economic growth of some countries, especially those in the transition process [3]. One of the reasons for that is the protocol, adopted in 2012 at Doha 2012 UN Climate Change Conference COP18 CMP8, at which the industrial world agreed to reduce the emissions of greenhouse gases approximately 18% below 1990 levels by 2013-2020 [4]. In the meantime, also due to the climate change and the increase in environmental awareness all over the world, the concept of Green Supply Chain Management appeared. It is often defined as integrating environmental thinking into supply chain management [5].Within that concept many greening elements aimed at the reduction of materials, energy, waste, pollution and emissions, or promoting the usage of recyclable materials and renewable energy sources, are introduced in various segments of supply chains. The proof lies in number of examples from industry, as well as in significant interest of academic community that could be seen through research papers, doctoral thesis and research projects.[...

Green supply chain management in Croatian companies

The scope of this paper is to present current state and trends of Green Supply Chain Management (GSCM) in Croatian companies. Due to the need for reduction of GHG emissions related to the climate change, many standards, directives, concepts, methods and models dealing with sustainability have appeared. The first part of the paper consists of an overview of GSCM where the greening diagram of GSCM is presented. The second part of the paper presents the survey which has been carried out in the Croatian business sector in view of current state and trends, barriers and drivers of the GSCM implementation. According to the results of the survey, barriers and drivers of the GSCM implementation are ranked by its significance and are compared with similar surveys carried out in the European Union (EU) and the United States of America (USA). New categorization of the drivers of the GSCM implementation is presented using the factor analysis

Condition Monitoring of Rotary Machinery Using Industrial IOT Framework: Step to Smart Maintenance

Modern maintenance strategies, such as predictive and prescriptive maintenance, which derived from the concept of Industry and Maintenance 4.0, involve the application of the Industrial Internet of Things (IIoT) to connect maintenance objects enabling data collection and analysis that can help make better decisions on maintenance activities. Data collection is the initial step and the foundation of any modern Predictive or Prescriptive maintenance strategy because it collects data that can then be analysed to provide useful information about the state of maintenance objects. Condition monitoring of rotary equipment is one of the most popular maintenance methods because it can distinguish machine state between multiple fault types. The topic of this paper is the presentation of an automated system for data collection, processing and interpretation of rotary equipment state that is based on IIoT framework consisting of an IIoT accelerometer, edge and fog devices, web API and database. Additionally, ISO 10816-1 guidance has been followed to develop module for evaluation of vibration severity. The collected data is also visualized in a dashboard in a near-real time and shown to maintenance engineering, which is crucial for pattern monitoring. The developed system was launched in laboratory conditions using rotating equipment failure simulator to test the logic of data collection and processing. A proposed system has shown that it is capable of automated periodic data collection and processing from remote places which is achieved using Node RED programming environment and MQTT communication protocol that enables reliable, lightweight, and secure data transmission

PI/PID Controller Relay Experiment Auto-Tuning with Extended Kalman Filter and Second-Order Generalized Integrator as Parameter Estimators

This paper presents a method for the estimation of key parameters of limit cycle oscillations (amplitude and frequency) during a relay experiment used for automatic tuning of proportional-integral (PI) and proportional-integral-derivative (PID) feedback controllers. The limit cycle parameter estimator is based on the first-order extended Kalman filter (EKF) for resonance frequency estimation, to which a second-order generalized integrator (SOGI) is cascaded for the purpose of limit cycle amplitude estimation. Based on thus-obtained parameters of the limit cycle oscillations, the ultimate gain and the ultimate period of the limit cycle oscillations are estimated. These are subsequently used for the tuning of PI and PID controller according to Takahashi modifications of Ziegler-Nichols tuning rules. The proposed PI and PID controller auto-tuning method is verified by means of simulations and experimentally on the heat and air-flow experimental setup for the case of air temperature feedback control. The results have shown that the proposed auto-tuning system based on relay control experiment for the heat and air-flow process PI/PID temperature control can capture the ultimate gain and period parameters fairly quickly in simulations and in experiments. Subsequent controller tuning according to Takahashi modifications of Ziegler-Nichols rules using thus-obtained ultimate point parameters can provide favourable closed-loop load disturbance rejection, particularly in the case of PID controller

PI/PID Controller Relay Experiment Auto-Tuning with Extended Kalman Filter and Second-Order Generalized Integrator as Parameter Estimators

This paper presents a method for the estimation of key parameters of limit cycle oscillations (amplitude and frequency) during a relay experiment used for automatic tuning of proportional-integral (PI) and proportional-integral-derivative (PID) feedback controllers. The limit cycle parameter estimator is based on the first-order extended Kalman filter (EKF) for resonance frequency estimation, to which a second-order generalized integrator (SOGI) is cascaded for the purpose of limit cycle amplitude estimation. Based on thus-obtained parameters of the limit cycle oscillations, the ultimate gain and the ultimate period of the limit cycle oscillations are estimated. These are subsequently used for the tuning of PI and PID controller according to Takahashi modifications of Ziegler-Nichols tuning rules. The proposed PI and PID controller auto-tuning method is verified by means of simulations and experimentally on the heat and air-flow experimental setup for the case of air temperature feedback control. The results have shown that the proposed auto-tuning system based on relay control experiment for the heat and air-flow process PI/PID temperature control can capture the ultimate gain and period parameters fairly quickly in simulations and in experiments. Subsequent controller tuning according to Takahashi modifications of Ziegler-Nichols rules using thus-obtained ultimate point parameters can provide favourable closed-loop load disturbance rejection, particularly in the case of PID controller

Identification of Inability States of Rotating Machinery Subsystems Using Industrial IoT and Convolutional Neural Network – Initial Research

Rotating parts can be found in almost all operational equipment in the industry and are of great importance for proper operation. However, reliability theory explains that every industrial system can change its state when failure happens. Predictive maintenance as one of the latest maintenance strategy emerged from the Maintenance 4.0 concept. Nowadays, this concept can include Industrial Internet of Things (IIoT) devices to connect industrial assets thus enable data collection and analysis that can help make better decisions about maintenance activity. Robust data acquisition system is a prerequisite for any modern predictive maintenance task as it provides necessary data for further analysis and health assessment of the industry asset. Fault diagnosis is an important task in the maintenance of industrial rotating subsystems, considering that early state change diagnosis and fault identification can prevent system failure. Vibration analysis in theory and practice is considered a correct technique for early detection of state changes and failure diagnostics of rotating subsystems. The identified technical state should be considered in a context of the ability and different inability states. Therefore, early different inability states identification is the next step in the rotary machinery diagnostics procedure. Most of the existing techniques for fault diagnosis of rotating subsystems that use vibrations involve the step of extracting features from the raw signal. Considering that the features that describe the behavior of the rotary subsystem can differ significantly depending on the type of equipment, such an approach usually requires an expert in the field of signal processing and rotary subsystems who can define the necessary features. Recently, the emergence of machine deep learning and its application in maintenance promises to provide highly efficient fault diagnostics while simultaneously reducing the need for expert knowledge and human labour. This paper presents authors aim to use self-developed IIoT system built as an IIoT accelerometer as the edge device, web API and database with convolutional neural network as deep learning-based data-driven fault diagnosis to detect and identify different inability states of rotating subsystems. Large dataset for two different rotational speed is collected using IIOT system and multiple convolutional neural network models are trained and tested to examine possibility of using IIOT for inability state prediction

Automation Systems Design and Laboratory Prototyping Aimed at Mature Petroleum Drilling Rig Retrofitting

This paper presents a control system design methodology for the drill-string rotary drive and draw-works hoist system aimed at mature drilling rig retrofitting. The rotary drive is equipped with an active damping speed control system featuring a proportional-integral speed controller readily available within modern controlled electrical drives, extended with drill-string back-spinning prevention scheme for the case of stuck tool. The draw-works hoist system features a tool normal force (Weight-on-Bit) controller with tool longitudinal speed (Rate-of-Penetration) limiting functionality. The design of proposed control systems has been based on suitable control-oriented process models and damping optimum criterion which guarantees a desired level of closed-loop system damping. The proposed drilling control systems have been verified on a downscaled laboratory experimental setup, which represents a necessary pre-requirement before these systems are tested in the field

UTJECAJ POSTRNIH USJEVA NA PRINOS I KOMPONENTE PRINOSA U EKOLOŠKOM UZGOJU KUKURUZA

The second crop use in organic agriculture is a known method of maintaining the soil tilth, soil protection against environmental deterioration, soil nutrients conservation and even the weed control. The nitrogen conservation from previous leguminose crop is even more important, especially in the organic agriculture where use of N-fertilizers is the strictly forbiden, and second crops can be used as a catch crops for nutrients in rotation prior to the crops with the high N requirement. The choice of the proper second crop has, however, been insufficiently investigated, especially for agri-environmental conditions of the Panonian agricultural area in Croatia. The second crop experiment was established in Valpovo, Croatia, in the eutric brown soil type, during the years 2005 and 2006. The aim of the experiment was to investigate the effects of different second crops and their combinations on maize (Zea mais L.) yield and yield components in organic agriculture after soybean (Glycine max L.) in crop rotation. The experimental design was set up as a CRBD in four repetitions, with soybean as a previous crop in crop rotation. The six second crop treatments were: O – Control, without second crop; WW – winter wheat (Triticum aestivum L.) second crop; RY – rye (Secale cereale L.) second crop; FP – fodder pea (Pisum arvense L.) second crop; WP – mixture of the WW and FP; and RP – mixture of RY and FP. The WW treatment had the highest second crop dry mass, whereas FP had the lowest dry mass. The highest plant density was recorded for FP, and it was higher than the RP plant density, which also had the lowest plant height. The achieved maize yields were the highest for RY, but they were not significanlty different from the O, RP, and WW treatments. However, the yield achieved by RY treatment was significantly higher than the yields recorded for WP and FP treatments. The absolute mass and hectolitre mass did not show any statistical differences among treatments.Upotreba postrnih usjeva u ekološkoj/organskoj poljoprivredi je priznata metoda za održavanje ugorenosti tla, zaštite tla protiv vremenskih neprilika, konzervacije hraniva u tlu te čak i borbe protiv korova. Konzervacija dušika od prethodnog leguminoznog usjeva je čak važnija funkcija, posebice u ekološkoj poljoprivredi gdje je upotreba mineralnih dušičnih gnojiva izrijekom zabranjena, te postrni usjevi mogu poslužiti za čuvanje dušika od ispiranja iz tla za sljedeći usjev u plodoredu s visokim zahtjevima za dušikom. Nažalost, izbor postrnih usjeva nije dostatno istražen, posebice za agroekološke uvjete u Hrvatskoj. Stoga je postavljen pokus u Valpovu, Republika Hrvatska, na eutričnom smeđem tlu, tijekom 2005. i 2006. godine, s ciljem da se istraže učinci različitih postrnih usjeva i njihovih kombinacija na komponente prinosa i prinos kukuruza (Zea mais L.) u ekološkoj (organskoj) poljoprivredi, a u plodoredu iza predusjeva soje (Glycine max L.). Pokus je postavljen kao potpuno slučajan blok raspored u četiri repeticije, sa šest tretmana postrnih usjeva: CT – kontrola, bez postrnih usjeva; WW – ozima pšenica (Triticum aestivum L.); RY – ozima raž (Secale cereale L.); FP – stočni grašak (Pisum arvense L.); WP – mješavina WW i FP; te RP – mješavina RY i FP. WW tretman imao je najveću masu postrnih usjeva, dok je FP imao najmanju masu postrnih usjeva. Najgušći sklop zabilježen je na FP tretmanu, značajno viši nego sklop na RP tretmanu, koji je također imao i najnižu visinu stabljika usjeva kukuruza. Ostvareni prinosi kukuruza bili su najviši na RY tretmanu, no nisu bili signifi-kantno različiti od O, RP i WW tretmana. Ipak, prinos zabilježen na RY tretmanu bio je signifikantno viši od prinosa na WP i FP tretma-nima. Apsolutna i hektolitarska masa nije se statistički razlikovala između tretmana

EKONOMSKA ODRŽIVOST PRIMJENE POSTRNIH USJEVA U EKOLOŠKOM UZGOJU KUKURUZA

Although organic crop production has numerous advantages, concerns about economic sustainability, both environmental and financial, make farmers reluctant to convert their conventional production into the organic production. Certain agricultural methods, such as second crop use, can alleviate some problems regarding soil tilth, erosion prevention, nutrients availability and weed control, thus contributing toward more sustainable crop production. Also, the added value crop growth, such as maize (Zea mais L.) hybrid\u27s parental line production, with lower yields but higher prices, can contribute to sustainability of organic production. In order to test the hypothesis that the use of second crops can contribute toward the sustainability of organically grown maize after soybean (Glycine max L.) as a previous crop in the crop rotation, the experimental site was established in Valpovo, Croatia, in the eutric brown soil type, during the years 2005 and 2006. The experimental design was set up as a CRBD in four repetitions, with six second crop treatments: CT – Control, without second crop; WW – winter wheat (Triticum aestivum L.) second crop; RY – rye (Secale cereale L.) second crop; FP – fodder pea (Pisum arvense L.) second crop; WP – mixture of WW and FP; and RP – mixture of RY and FP. In order to assess the soil surface protection and evaluate the weed suppression, the second crop coverage had been recorded. Regarding the economic sustainability, the second crop use depending costs were analysed in relation to the extra produced maize yield. The RY treatment had the highest profitability, followed by WW, RP and O. The WP and FP revealed lower relative profitability than O, thus presenting the evidence of sustainability risk of these treatments.Premda ekološka poljoprivreda ima brojnih prednosti, zabrinutost zbog održivosti, i ekološke i ekonomske, farmere često odvraća od prijelaza s konvencionalne proizvodnje na ekološku. Intenzifikacijom plodoreda uporabom postrnih usjeva, mogu ukloniti neke probleme vezane za ugorenost tla, prevenciju erozije, dostupnost hraniva i suzbijanje korova, doprinoseći na taj način održivosti proizvodnje usjeva. Također, uzgoj usjeva s dodatnom vrijednošću, kao što su roditeljske linije za proizvodnju hibrida kukuruza (Zea mais L.), s nižim prinosima ali višom cijenom, može pridonijeti održivosti (profitabilnosti) ekološke proizvodnje. U namjeri da se potvrdi hipoteza da postrni usjevi mogu doprinijeti održivosti ekološkog uzgoja kukuruza u dvopoljnom plodoredu sa sojom (Glycine max L.) kao prethodnim usjevom, postavljeno je pokušalište u Valpovu, Hrvatska, na eutričnom smeđem tlu, tijekom 2005. i 2006. godine. Pokus je postavljen kao potpuno slučajan blok raspored u četiri ponavljanja, sa šest tretmana postrnih usjeva: CT – kontrola, bez postrnih usjeva; WW – ozima pšenica (Triticum aestivum L.); RY – ozima raž (Secale cereale L.); FP – stočni grašak (Pisum arvense L.); WP – smjesa WW i FP; te RP – smjesa RY i FP. U cilju određivanja zaštite površine tla i evaluacije suzbijanja korova, zabilježena je pokrivenost postrnim usjevima. Glede isplativosti, analizirani su relativni troškovi upotrebe postrnih usjeva u odnosu na dodatno proizvedeni urod kukuruza. RY tretman je zabilježio najvišu profitabilnost, a pratili su ga tretmani WW, RP i O. Tretmani WP i FP pokazali su se manje profitabilni od O, time pružajući dokaze o rizičnoj održivosti ovih tretmana