Uređaj za kalanje odrezaka trupaca za potpalu

Osnovna ideja ovog rada je bila izrada konstrukcijskog rješenja niskobudžetnog poluautomatskog uređaja za kalanje već narezanih trupaca. Prvenstveno, potreba za uređajem dolazi iz manjih kućanstva u manjim naseljenim mjestima zbog dinamike života u manje naseljenim mjestima, ekološke prihvatljivosti energenata i cijene energenata. Poluautomatski rad bi operateru olakšao rad uštedivši mu vrijeme i energiju. Kroz analizu tržišta je dobiven uvid u razne izvedbe već postojećih cjepača, od primitivnih do složenih mehaniziranih sustava. Nakon provedene analize tržišta izrađena je evaluacija iste te su definirane smjernice za razvoj ovisno o zahtjevima iz teksta zadatka završnog rada. Tijekom konceptualne faze bile su uzete u obzir sve smjernice i zahtjevi te je izabran završni modificirani koncept. Konačno, prilikom detaljiranja odabranog koncepta proveden je orijentacijski proračun pojedinih vitalnih komponenti/sustava te je izrađena tehnička dokumentacija

Firewood splitting device

Osnovna ideja ovog rada je bila izrada konstrukcijskog rješenja niskobudžetnog poluautomatskog uređaja za kalanje već narezanih trupaca. Prvenstveno, potreba za uređajem dolazi iz manjih kućanstva u manjim naseljenim mjestima zbog dinamike života u manje naseljenim mjestima, ekološke prihvatljivosti energenata i cijene energenata. Poluautomatski rad bi operateru olakšao rad uštedivši mu vrijeme i energiju. Kroz analizu tržišta je dobiven uvid u razne izvedbe već postojećih cjepača, od primitivnih do složenih mehaniziranih sustava. Nakon provedene analize tržišta izrađena je evaluacija iste te su definirane smjernice za razvoj ovisno o zahtjevima iz teksta zadatka završnog rada. Tijekom konceptualne faze bile su uzete u obzir sve smjernice i zahtjevi te je izabran završni modificirani koncept. Konačno, prilikom detaljiranja odabranog koncepta proveden je orijentacijski proračun pojedinih vitalnih komponenti/sustava te je izrađena tehnička dokumentacija.The basic idea of this paper was to create a design solution of a low-budget semi-automatic firewood splitting device for already trimmed logs. Primarily, the need for the device comes from smaller households in less populated areas because of the dynamics of living in less populated places, ecologically acceptable energy sources and energy prices. Semi-automatic work would make the whole operation easier by saving people’s time and energy. Through the market analysis, insights have been gained on the various performances of already existing piles, from primitive to complex mechanized systems. After the conducted market analysis, the evaluation was done, and the development guidelines defined, depending on the requirements of the default task. During the conceptual design, all the guidelines and requirements were considered, and the final modified concept was chosen. Finally, in the detailing of the chosen concept, the orientational estimation for each vital component / system was done and technical documentation was developed

Design of a Wireless Drone Recharging Station and a Special Robot End Effector for Installation on a Power Line

Drone autonomous operations near power lines are growing steadily and require innovative techniques to keep them on air. This paper presents a novel electromechanical recharging station that can be mounted on energized AC power line to charge the drone battery wirelessly without a need to modify the electrical infrastructure. The work shows a thorough analysis of the electrical and mechanical core components to build a flexible, lightweight and efficient recharging station that can be attached to a robotic arm. The work also discusses the recharging station design and its special robot end effector that mechanically couples the station with an aerial manipulator. Finally, the recharging station has been tested in the lab and in a real power line setup to validate its design and efficiency. The total achieved mass is 2300 grams with a harvesting efficiency of 77% at 250 A primary current

Modelling of high cyclic fatigue behaviour of sinter steel by considering microstructural effects

Tehnologija metalurgije praha ima brojne prednosti nad klasičnom metalurgijom. No, kod proizvodnje dijelova tehnologijom metalurgije praha zbog postupka koji se sastoji od tlačenja praškastog materijala u kalupu koji se nakon toga zagrijava na odgovarajuću temperaturu u nekom vremenskom intervalu, u gotovom proizvodu dolazi do pojave zaostale poroznosti. Stoga je ovom diplomskom radu razmatran utjecaj mikrostrukture sinteriranog čelika na njegovo zamorno ponašanje u uvjetima visokocikličkog zamora. U radu je razmatran sinterirani čelik Astaloy Mo+0,2C. Detaljno je objašnjena metodologija numeričkog modeliranja zamora materijala i konstitutivnog ponašanja heterogenih materijala. Na temelju metalografskih ispitivanja je određen reprezentativni volumenski element (RVE) koji statistički predstavlja ponašanje mikrostrukture heterogenog materijala. Nadalje, određene su linearno-elastične karakteristike feritne matrice sinteriranog čelika primjenom homogenizacije na prethodno definiranom RVEu, koje su poslužile kao temelj prilikom procjene visokocikličkog zamora. Numeričke simulacije su provedene u programsku paketu Abaqus. Nakon određivanja linearno elastičnog ponašanja, određene su zamorne karakteristike feritne matrice Astaloya Mo+0,2C uz eksplicitno razmatranje mikrostrukture materijala. Kod određivanja zamornih karakteristika feritne matrice u uvjetima visokocikličkog zamora, razmatrana su dva slučaja: bez razmatranja utjecaja srednjeg naprezanja i s razmatranjem utjecaja srednjeg naprezanja prema Goodmanu. Numeričke simulacije zamornog ponašanja provedene su u programskom paketu fe-safe. Nažalost, eksperimentalna ispitivanja mehaničkih karakteristika Astaloya Mo+0,2C nisu u potpunosti provedena zbog posljedica uzrokovanih pandemijom koronavirusa Covid-19. Zbog toga nije bila moguća validacija rezultata numeričkih simulacija, a materijalne karakteristike materijala nužne za provedbu numeričkih analiza su preuzete iz literature.Powder metallurgy technology has numerous advantages over classical metallurgy. However, in the production of parts by powder metallurgy technology due to a process consisting of pressing the powdered material in a mold which is then heated to the appropriate temperature in a certain time interval, residual porosity occurs in the finished product. Therefore, this master's thesis discusses the influence of the microstructure of sintered steel on its fatigue behavior under conditions of high-cyclic fatigue. The material considered is sintered steel Astaloy Mo+0.2C. The methodology of numerical modeling of material fatigue and the constitutive behavior of heterogeneous materials is explained in detail. Based on the metallographic testing, a representative volume element (RVE) was determined, which statistically represents the microstructural behavior of the heterogeneous material. Furthermore, the linear-elastic characteristics of the sintered steel ferrite matrix were determined using homogenization on a predefined RVE, which served as a basis in the assessment of high-cyclic fatigue. Numerical simulations were performed in the software package Abaqus. After determining the linear elastic behavior, the fatigue characteristics of the Astaloy Mo+0.2C ferrite matrix were determined by explicit consideration of the material microstructure. During determination the fatigue characteristics of the ferrite matrix under conditions of high-cyclic fatigue, two cases were considered: without the influence of medium stress and with consideration of the influence of medium stress according to Goodman. Numerical simulations of fatigue behavior were performed in the software package fe-safe. Unfortunately, experimental study of the mechanical properties of Astaloy Mo+0.2C has not been fully performed due to the consequences caused by the Covid-19 coronavirus pandemic. Therefore, it was not possible to validate the results of numerical simulations, while the material characteristics necessary for the conduction of numerical analyzes were taken from the literature

Firewood splitting device

Osnovna ideja ovog rada je bila izrada konstrukcijskog rješenja niskobudžetnog poluautomatskog uređaja za kalanje već narezanih trupaca. Prvenstveno, potreba za uređajem dolazi iz manjih kućanstva u manjim naseljenim mjestima zbog dinamike života u manje naseljenim mjestima, ekološke prihvatljivosti energenata i cijene energenata. Poluautomatski rad bi operateru olakšao rad uštedivši mu vrijeme i energiju. Kroz analizu tržišta je dobiven uvid u razne izvedbe već postojećih cjepača, od primitivnih do složenih mehaniziranih sustava. Nakon provedene analize tržišta izrađena je evaluacija iste te su definirane smjernice za razvoj ovisno o zahtjevima iz teksta zadatka završnog rada. Tijekom konceptualne faze bile su uzete u obzir sve smjernice i zahtjevi te je izabran završni modificirani koncept. Konačno, prilikom detaljiranja odabranog koncepta proveden je orijentacijski proračun pojedinih vitalnih komponenti/sustava te je izrađena tehnička dokumentacija.The basic idea of this paper was to create a design solution of a low-budget semi-automatic firewood splitting device for already trimmed logs. Primarily, the need for the device comes from smaller households in less populated areas because of the dynamics of living in less populated places, ecologically acceptable energy sources and energy prices. Semi-automatic work would make the whole operation easier by saving people’s time and energy. Through the market analysis, insights have been gained on the various performances of already existing piles, from primitive to complex mechanized systems. After the conducted market analysis, the evaluation was done, and the development guidelines defined, depending on the requirements of the default task. During the conceptual design, all the guidelines and requirements were considered, and the final modified concept was chosen. Finally, in the detailing of the chosen concept, the orientational estimation for each vital component / system was done and technical documentation was developed

Modelling of high cyclic fatigue behaviour of sinter steel by considering microstructural effects

Tehnologija metalurgije praha ima brojne prednosti nad klasičnom metalurgijom. No, kod proizvodnje dijelova tehnologijom metalurgije praha zbog postupka koji se sastoji od tlačenja praškastog materijala u kalupu koji se nakon toga zagrijava na odgovarajuću temperaturu u nekom vremenskom intervalu, u gotovom proizvodu dolazi do pojave zaostale poroznosti. Stoga je ovom diplomskom radu razmatran utjecaj mikrostrukture sinteriranog čelika na njegovo zamorno ponašanje u uvjetima visokocikličkog zamora. U radu je razmatran sinterirani čelik Astaloy Mo+0,2C. Detaljno je objašnjena metodologija numeričkog modeliranja zamora materijala i konstitutivnog ponašanja heterogenih materijala. Na temelju metalografskih ispitivanja je određen reprezentativni volumenski element (RVE) koji statistički predstavlja ponašanje mikrostrukture heterogenog materijala. Nadalje, određene su linearno-elastične karakteristike feritne matrice sinteriranog čelika primjenom homogenizacije na prethodno definiranom RVEu, koje su poslužile kao temelj prilikom procjene visokocikličkog zamora. Numeričke simulacije su provedene u programsku paketu Abaqus. Nakon određivanja linearno elastičnog ponašanja, određene su zamorne karakteristike feritne matrice Astaloya Mo+0,2C uz eksplicitno razmatranje mikrostrukture materijala. Kod određivanja zamornih karakteristika feritne matrice u uvjetima visokocikličkog zamora, razmatrana su dva slučaja: bez razmatranja utjecaja srednjeg naprezanja i s razmatranjem utjecaja srednjeg naprezanja prema Goodmanu. Numeričke simulacije zamornog ponašanja provedene su u programskom paketu fe-safe. Nažalost, eksperimentalna ispitivanja mehaničkih karakteristika Astaloya Mo+0,2C nisu u potpunosti provedena zbog posljedica uzrokovanih pandemijom koronavirusa Covid-19. Zbog toga nije bila moguća validacija rezultata numeričkih simulacija, a materijalne karakteristike materijala nužne za provedbu numeričkih analiza su preuzete iz literature.Powder metallurgy technology has numerous advantages over classical metallurgy. However, in the production of parts by powder metallurgy technology due to a process consisting of pressing the powdered material in a mold which is then heated to the appropriate temperature in a certain time interval, residual porosity occurs in the finished product. Therefore, this master's thesis discusses the influence of the microstructure of sintered steel on its fatigue behavior under conditions of high-cyclic fatigue. The material considered is sintered steel Astaloy Mo+0.2C. The methodology of numerical modeling of material fatigue and the constitutive behavior of heterogeneous materials is explained in detail. Based on the metallographic testing, a representative volume element (RVE) was determined, which statistically represents the microstructural behavior of the heterogeneous material. Furthermore, the linear-elastic characteristics of the sintered steel ferrite matrix were determined using homogenization on a predefined RVE, which served as a basis in the assessment of high-cyclic fatigue. Numerical simulations were performed in the software package Abaqus. After determining the linear elastic behavior, the fatigue characteristics of the Astaloy Mo+0.2C ferrite matrix were determined by explicit consideration of the material microstructure. During determination the fatigue characteristics of the ferrite matrix under conditions of high-cyclic fatigue, two cases were considered: without the influence of medium stress and with consideration of the influence of medium stress according to Goodman. Numerical simulations of fatigue behavior were performed in the software package fe-safe. Unfortunately, experimental study of the mechanical properties of Astaloy Mo+0.2C has not been fully performed due to the consequences caused by the Covid-19 coronavirus pandemic. Therefore, it was not possible to validate the results of numerical simulations, while the material characteristics necessary for the conduction of numerical analyzes were taken from the literature

Firewood splitting device

Osnovna ideja ovog rada je bila izrada konstrukcijskog rješenja niskobudžetnog poluautomatskog uređaja za kalanje već narezanih trupaca. Prvenstveno, potreba za uređajem dolazi iz manjih kućanstva u manjim naseljenim mjestima zbog dinamike života u manje naseljenim mjestima, ekološke prihvatljivosti energenata i cijene energenata. Poluautomatski rad bi operateru olakšao rad uštedivši mu vrijeme i energiju. Kroz analizu tržišta je dobiven uvid u razne izvedbe već postojećih cjepača, od primitivnih do složenih mehaniziranih sustava. Nakon provedene analize tržišta izrađena je evaluacija iste te su definirane smjernice za razvoj ovisno o zahtjevima iz teksta zadatka završnog rada. Tijekom konceptualne faze bile su uzete u obzir sve smjernice i zahtjevi te je izabran završni modificirani koncept. Konačno, prilikom detaljiranja odabranog koncepta proveden je orijentacijski proračun pojedinih vitalnih komponenti/sustava te je izrađena tehnička dokumentacija.The basic idea of this paper was to create a design solution of a low-budget semi-automatic firewood splitting device for already trimmed logs. Primarily, the need for the device comes from smaller households in less populated areas because of the dynamics of living in less populated places, ecologically acceptable energy sources and energy prices. Semi-automatic work would make the whole operation easier by saving people’s time and energy. Through the market analysis, insights have been gained on the various performances of already existing piles, from primitive to complex mechanized systems. After the conducted market analysis, the evaluation was done, and the development guidelines defined, depending on the requirements of the default task. During the conceptual design, all the guidelines and requirements were considered, and the final modified concept was chosen. Finally, in the detailing of the chosen concept, the orientational estimation for each vital component / system was done and technical documentation was developed

Modelling of high cyclic fatigue behaviour of sinter steel by considering microstructural effects

Tehnologija metalurgije praha ima brojne prednosti nad klasičnom metalurgijom. No, kod proizvodnje dijelova tehnologijom metalurgije praha zbog postupka koji se sastoji od tlačenja praškastog materijala u kalupu koji se nakon toga zagrijava na odgovarajuću temperaturu u nekom vremenskom intervalu, u gotovom proizvodu dolazi do pojave zaostale poroznosti. Stoga je ovom diplomskom radu razmatran utjecaj mikrostrukture sinteriranog čelika na njegovo zamorno ponašanje u uvjetima visokocikličkog zamora. U radu je razmatran sinterirani čelik Astaloy Mo+0,2C. Detaljno je objašnjena metodologija numeričkog modeliranja zamora materijala i konstitutivnog ponašanja heterogenih materijala. Na temelju metalografskih ispitivanja je određen reprezentativni volumenski element (RVE) koji statistički predstavlja ponašanje mikrostrukture heterogenog materijala. Nadalje, određene su linearno-elastične karakteristike feritne matrice sinteriranog čelika primjenom homogenizacije na prethodno definiranom RVEu, koje su poslužile kao temelj prilikom procjene visokocikličkog zamora. Numeričke simulacije su provedene u programsku paketu Abaqus. Nakon određivanja linearno elastičnog ponašanja, određene su zamorne karakteristike feritne matrice Astaloya Mo+0,2C uz eksplicitno razmatranje mikrostrukture materijala. Kod određivanja zamornih karakteristika feritne matrice u uvjetima visokocikličkog zamora, razmatrana su dva slučaja: bez razmatranja utjecaja srednjeg naprezanja i s razmatranjem utjecaja srednjeg naprezanja prema Goodmanu. Numeričke simulacije zamornog ponašanja provedene su u programskom paketu fe-safe. Nažalost, eksperimentalna ispitivanja mehaničkih karakteristika Astaloya Mo+0,2C nisu u potpunosti provedena zbog posljedica uzrokovanih pandemijom koronavirusa Covid-19. Zbog toga nije bila moguća validacija rezultata numeričkih simulacija, a materijalne karakteristike materijala nužne za provedbu numeričkih analiza su preuzete iz literature.Powder metallurgy technology has numerous advantages over classical metallurgy. However, in the production of parts by powder metallurgy technology due to a process consisting of pressing the powdered material in a mold which is then heated to the appropriate temperature in a certain time interval, residual porosity occurs in the finished product. Therefore, this master's thesis discusses the influence of the microstructure of sintered steel on its fatigue behavior under conditions of high-cyclic fatigue. The material considered is sintered steel Astaloy Mo+0.2C. The methodology of numerical modeling of material fatigue and the constitutive behavior of heterogeneous materials is explained in detail. Based on the metallographic testing, a representative volume element (RVE) was determined, which statistically represents the microstructural behavior of the heterogeneous material. Furthermore, the linear-elastic characteristics of the sintered steel ferrite matrix were determined using homogenization on a predefined RVE, which served as a basis in the assessment of high-cyclic fatigue. Numerical simulations were performed in the software package Abaqus. After determining the linear elastic behavior, the fatigue characteristics of the Astaloy Mo+0.2C ferrite matrix were determined by explicit consideration of the material microstructure. During determination the fatigue characteristics of the ferrite matrix under conditions of high-cyclic fatigue, two cases were considered: without the influence of medium stress and with consideration of the influence of medium stress according to Goodman. Numerical simulations of fatigue behavior were performed in the software package fe-safe. Unfortunately, experimental study of the mechanical properties of Astaloy Mo+0.2C has not been fully performed due to the consequences caused by the Covid-19 coronavirus pandemic. Therefore, it was not possible to validate the results of numerical simulations, while the material characteristics necessary for the conduction of numerical analyzes were taken from the literature

Direct Drive Brush-Shaped Tool with Torque Sensing Capability for Compliant Robotic Vine Suckering

In this paper, we present a direct drive brush-shaped tool developed for the use of robotic vine suckering. Direct drive design philosophy allows for precise and high bandwidth control of the torque exerted by the brush. Besides limiting the torque exerted onto the plant, this kind of design philosophy allows the brush to be used as a torque sensor. High bandwidth torque feedback from the tool is used to enable a position controlled robot arm to perform the suckering task without knowing the exact position and shape of the trunk of the vine. An experiment was conducted to investigate the dependency of the applied torque on the overlap between the brush and the obstacle. The results of the experiment indicate a quadratic relationship between torque and overlap. This quadratic function is estimated and used for compliant trunk shape following. A trunk shape following experiment demonstrates the utility of the presented tool to be used as a sensor for compliant robot arm control. The shape of the trunk is estimated by tracking the motion of the robot arm during the experiment

Object Localization by Construction of an Asymmetric Isobody of The Magnetic Gradient Tensor Contraction Using Two Identical Permanent Magnets

This paper deals with predictive maintenance of infrastructure objects, focusing on the inspection of bridges. To achieve this goal, unmanned aerial vehicles place measuring units for data collection at different points of the bridge. This work deals with the question of how these measuring units can be found and removed by them later. For this purpose, a magnetic localization method based on the STAR method is presented. In contrast to the STAR method, which only detects the center of a magnetic target, a modified version called SRIOD is implemented here, where the orientation of the magnetic target can also be detected. This is essential information if the unmanned aerial vehicle is to grab the measuring unit with a robotic arm. In this regard, two identical permanent magnets are integrated into the measuring unit, whose gradient tensor contraction of the magnetic flux density distribution has a directed asymmetric surface when considering the contours of constant values. This creates a magnetic invisible reference plane that can be detected with a magnetic gradiometer. The method is verified both in simulation and experimentally in a laboratory setup. </p