In most mine clearing or earth moving equipment such as bulldozers, the working tool is a blade. The blade geometry and operating conditions, such as cutting speed, cutting angle, and cutting depth, have a great effect on overall machine productivity. Most of the published experimental studies confirm these effects. However experimental studies are expensive and their results are highly dependant on the accuracy of measurement devices and the reliability of experimental procedures employed. Numerical techniques have recently shown more promise especially with the current increase in computational power and development of more sophisticated material models. However in order to simulate the soil-tool interface process accurately, careful selection of the appropriate material model for the soil and the interface is required. This should, ideally, be based on a reasonable number of material parameters that have direct physical meaning. In this study a review of the available constitu tive models for soil (particularly sand) and soil-tool interface was carried out. This review study concluded by selecting the so called hypoplastic model as the most appropriate to simulate the sandy soil behavior over a wide range of stresses. Some modifications were carried out on this selected hypoplastic model to optimize it for simulation of the soil-tool interaction process, which is characterized by monotonic loading and high deformation. The modified model was verified numerically and then implemented into the finite element method via an ABAQUS user defined subroutine UMAT. Then the implemented model was verified through analysis of some benchmark problems and results were compared with results from different classical failure criteria. The finite element analysis revealed the high performance of the hypoplastic model in simulating sand behaviour. Finally an analysis of various factors affecting soil-tool interaction was carried out in both two-dimensions and three-dimensions. Results revealed the significant effect of both geometry and operating conditions on blade cutting forces and confirmed the ability of the finite element method to analyze the soil-tool interaction process.

The phrase “miner” is comparatively non-specific as mining is seen as a multi-disciplinary industry that includes several diverse professions and trades (Donoghue, 2004). One of the functions within mining is the operation of earth moving equipment (EME) such as haul trucks, dozers, excavators and graders. EME are generally used to shift large amounts of earth, dig foundations and landscape areas. In this study whole-body vibration (WBV) and noise exposure of earth moving equipment (EME) operators were assessed, at an opencast coalmine in South Africa. The aim was to evaluate and quantify the levels of exposure in different EME types, as well as to compare old with new EME, in order to estimate if machine hours contribute to higher noise and vibration levels. WBV and noise levels of the Production and Rehabilitation operations were compared, to determine whether different activities led to different exposures. Internationally accepted standardised methods, ISO 2631-1 for WBV and SANS 10083:2012 for noise were followed and correctly calibrated instrumentation was used. WBV measurements were conducted with a tri-axial seat pad accelerometer (SVAN 958) and personal noise dosimeters (Casella 35 X) were used for noise measurements. Measurements were taken over a period of four months. With regards to the European Union (EU) limit (1.15 m/s2) and the EU action limit (0.5 m/s2) it was noted that operators of EME within the Production operation were not exposed to WBV levels above the EU limit, but 77% of these operators were exposed to WBV levels above the EU action limit. It was also evident that 45% of operators’ vibration exposure levels were within the Health Guidance Caution Zone (HGCZ) of 0.45 – 0.90 m/s2. Within the Rehabilitation operation, 9% of operators were exposed to WBV levels above the EU limit and 55% above the EU action limit. Furthermore 50% was within the HGCZ. With regards to the noise Occupational exposure limit (OEL) of 85 dB(A) as stated by the Mine Health and Safety Regulations (MHSR) it was noted that 27% of operators within the Production operation were exposed to noise levels above the limit and for operators within the Rehabilitation operation 14% were reported to be exposed at or above the limit. Statistically significant difference in noise exposure was found between the Production operation and Rehabilitation operation. Results indicated that the majority of EME operators were exposed to high noise levels, in some cases exceeding the 85 dB(A) OEL. A significant positive correlation was found between noise exposure levels and machine hours. Thus higher noise levels were observed as machine operating hours increased. It was found that operators were exposed predominantly to vibration and noise levels below the limits. However the Dozer group within the Production and Rehabilitation operations in some cases exceeded the vibration and noise legal limit. High exposure levels within the Dozer group can be attributed to the fact that these EME types mostly perform activities in uneven areas and the tracks on which these Dozers move also contribute to higher vibration levels due to a lack of a suspension. Controls should be implemented as far as is reasonably practicable to ensure that operators are not exposed above recommended or permissible levels for each hazard. Continuous improvement of the maintenance plan for all EME and regularly grading and maintaining travelling ways are some of the controls that will contribute to lower vibration and noise levels. Operators exposed to high noise levels should use hearing protective devices as an early on preventative measure to reduce noise exposure levels. / MSc (Occupational Hygiene), North-West University, Potchefstroom Campus, 2014

The phrase “miner” is comparatively non-specific as mining is seen as a multi-disciplinary industry that includes several diverse professions and trades (Donoghue, 2004). One of the functions within mining is the operation of earth moving equipment (EME) such as haul trucks, dozers, excavators and graders. EME are generally used to shift large amounts of earth, dig foundations and landscape areas. In this study whole-body vibration (WBV) and noise exposure of earth moving equipment (EME) operators were assessed, at an opencast coalmine in South Africa. The aim was to evaluate and quantify the levels of exposure in different EME types, as well as to compare old with new EME, in order to estimate if machine hours contribute to higher noise and vibration levels. WBV and noise levels of the Production and Rehabilitation operations were compared, to determine whether different activities led to different exposures. Internationally accepted standardised methods, ISO 2631-1 for WBV and SANS 10083:2012 for noise were followed and correctly calibrated instrumentation was used. WBV measurements were conducted with a tri-axial seat pad accelerometer (SVAN 958) and personal noise dosimeters (Casella 35 X) were used for noise measurements. Measurements were taken over a period of four months. With regards to the European Union (EU) limit (1.15 m/s2) and the EU action limit (0.5 m/s2) it was noted that operators of EME within the Production operation were not exposed to WBV levels above the EU limit, but 77% of these operators were exposed to WBV levels above the EU action limit. It was also evident that 45% of operators’ vibration exposure levels were within the Health Guidance Caution Zone (HGCZ) of 0.45 – 0.90 m/s2. Within the Rehabilitation operation, 9% of operators were exposed to WBV levels above the EU limit and 55% above the EU action limit. Furthermore 50% was within the HGCZ. With regards to the noise Occupational exposure limit (OEL) of 85 dB(A) as stated by the Mine Health and Safety Regulations (MHSR) it was noted that 27% of operators within the Production operation were exposed to noise levels above the limit and for operators within the Rehabilitation operation 14% were reported to be exposed at or above the limit. Statistically significant difference in noise exposure was found between the Production operation and Rehabilitation operation. Results indicated that the majority of EME operators were exposed to high noise levels, in some cases exceeding the 85 dB(A) OEL. A significant positive correlation was found between noise exposure levels and machine hours. Thus higher noise levels were observed as machine operating hours increased. It was found that operators were exposed predominantly to vibration and noise levels below the limits. However the Dozer group within the Production and Rehabilitation operations in some cases exceeded the vibration and noise legal limit. High exposure levels within the Dozer group can be attributed to the fact that these EME types mostly perform activities in uneven areas and the tracks on which these Dozers move also contribute to higher vibration levels due to a lack of a suspension. Controls should be implemented as far as is reasonably practicable to ensure that operators are not exposed above recommended or permissible levels for each hazard. Continuous improvement of the maintenance plan for all EME and regularly grading and maintaining travelling ways are some of the controls that will contribute to lower vibration and noise levels. Operators exposed to high noise levels should use hearing protective devices as an early on preventative measure to reduce noise exposure levels. / MSc (Occupational Hygiene), North-West University, Potchefstroom Campus, 2014

Diploma thesis deals with a design of a tractor earthmoving tipper and a stress analysis of its bath body. The first part contains an overview of similar construction solutions and a summary of related legislative requirements. Next part is followed up by a description of the tipper and its load conditions. The main part is focused on a stress analysis itself. Achieved results are evaluated at the end of this thesis. A partial technical documentation is also part of this work. This thesis was created in cooperation with company ZDT Nové Veselí.

Event-based vision offers high dynamic range, time resolution and lower latency than conventional frame-based vision sensors. These attributes are useful in varying light condition and fast motion. However, there are no neural network models and training protocols optimized for object detection with event data, and conventional artificial neural networks for frame-based data are not directly suitable for that task. Spiking neural networks are natural candidates but further work is required to develop an efficient object detection architecture and end-to-end training protocol. For example, object detection in varying light conditions is identified as a challenging problem for the automation of construction equipment such as earth-moving machines, aiming to increase the safety of operators and make repetitive processes less tedious. This work focuses on the development and evaluation of a neural network for object detection with data from an event-based sensor. Furthermore, the strengths and weaknesses of an event-based vision solution are discussed in relation to the known challenges described in former works on automation of earth-moving machines. A solution for object detection with event data is implemented as a modified YOLOv3 network with spiking convolutional layers trained with a backpropagation algorithm adapted for spiking neural networks. The performance is evaluated on the N-Caltech101 dataset with classes for airplanes and motorbikes, resulting in a mAP of 95.8% for the combined network and 98.8% for the original YOLOv3 network with the same architecture. The solution is investigated as a proof of concept and suggestions for further work is described based on a recurrent spiking neural network.

The construction industry has lagged behind other industries in productivity growth rate. Earth-moving sites, and other practices where dumpers are used, are no exceptions. Such projects lack convenient and accurate solutions for utilization mapping and tracking of mass flows, which both currently and mainly rely on manual activity tracking. This study intends to provide insights of how autonomous systems for activity tracking of dumpers can contribute to the productivity at earthmoving sites. Autonomous systems available on the market are not implementable to dumper fleets of various manufacturers and model year, whereas this study examines the possibilities of using activity recognition by machine learning for a system based on smartphones mounted in the driver’s cabin. Three machine learning algorithms (naive Bayes, random forest and feed-forward backpropagation neural network) are trained and tested on data collected by smartphone sensors. Conclusions are that machine learning models, and particularly the neural network and random forest algorithms, trained on data from a standard smartphone, are able to estimate a dumper’s activities at a high degree of certainty. Finally, a market analysis is presented, identifying the innovation opportunity for a potential end-product as high. / Byggnadsbranschen har halkat efter andra branscher i produktivitetsökning. Markarbetesprojekt och andra arbeten där dumprar används är inga undantag. Sådana projekt saknar användarvänliga system för att kartlägga maskinutnyttjande och massaflöde. Nuvarande lösningar bygger framförallt på manuellt arbete. Denna studie syftar skapa kännedom kring hur autonoma system för aktivitetsspårning av dumprar kan öka produktiviteten på markarbetesprojekt. Befintliga autonoma lösningar är inte implementerbara på maskinparker med olika fabrikat eller äldre årsmodeller. Denna studie undersöker möjligheten att applicera aktivitetsigenkänning genom maskininlärning baserad på smartphones placerade i förarhytten för en sådan autonom lösning. Tre maskininlärningsalgoritmer (naive Bayes, random forest och backpropagation neuralt nätverk) tränas och testas på data från sensorer tillgängliga i vanliga smartphones. Studiens slutsatser är att maskininlärningsmodeller, i synnerhet neuralt nätverk och random forest-algoritmerna, tränade på data från vanliga smartphones, till hög grad kan känna igen en dumpers aktiviteter. Avslutningsvis presenteras en marknadsanalys som bedömer innovationsmöjligheten för en eventuell slutprodukt som hög.

Digital transformation has become a hot topic both amongst practitioners and researchers. However, a vast majority of industries are struggling with collecting the benefits from digital transformation, and the Swedish earth-moving industry is no exception. Identity is seldomly further explored, although it is often mentioned as a factor to consider in digital transformation. Furthermore, the role of the employees is central, yet often underestimated. Thus, this study revolves around heavy equipment operators and their professional identity in digital transformation. Hence, the purpose of this study is to investigate how the professional identity of the heavy equipment operators affects digital transformation of the earth-moving industry. To fulfill the purpose, this study aims to use a combination of previous theories regarding professional identity. This to explain current and anticipate future supportive and resistive behaviors towards digital transformation. The findings are based on an exploratory case study of heavy equipment operators and an extensive literature review of prior research of professional identity. The findings showcase that heavy equipment operators' professional identity is mainly rooted in their prior socialization and similar values of impacting their surroundings. Furthermore, this study found that concerns of not having the skills required by the changes as a resistive behavior are likely to become more prominent in the future. This is because although digital technologies lower the maneuvering skills, they require other skills. Also, digital technologies are often appreciated although they are often adopted in a reactive way which slows down digital transformation of the earth-moving industry. Furthermore, this study shows that there are multiple aspects of professional identity to consider and provides a comprehensive understanding of the interdependencies amongst the elements in professional identity. / Digital transformation har blivit ett aktuellt ämne både bland företagare och forskare. En stor majoritet av företag och branscher kämpar dock med att framgångsrikt gå igenom en digital transformation, där den svenska maskinentreprenadbranschen inte är ett undantag. Identitet utforskas sällan vidare trots att det ofta nämns som en faktor att beakta vid digital transformation. Samtidigt är individernas roll central i en förändring, men ofta underskattad. Således kretsar denna studie kring maskinförare och deras yrkesidentitet i en digital transformation. Syftet med denna studie är att undersöka hur yrkesidentiteten hos maskinförare påverkar den digitala transformationen av maskinentreprenadbranschen. För att uppnå syftet ämnar denna studie till att först kombinera tidigare teorier kring yrkesidentitet till ett ramverk. Därefter använda ramverket till att förklara nuvarande och förutse framtida stödjande och hindrande beteenden mot digital transformation. Resultaten är baserade på en fallstudie av maskinförare och en omfattande litteraturstudie av tidigare forskning om yrkesidentitet. Resultaten visar att maskinförares yrkesidentitet huvudsakligen härstammar från deras tidigare socialisering och att de även har liknande värderingar av att påverka deras omgivning. Denna studie visade att oro för att inte ha de färdigheter som krävs av förändringarna sannolikt kommer bli mer framträdande i framtiden. Detta beror på att även om digital teknik sänker kraven för manövrering så kräver de andra typer av färdigheter. Vidare så uppskattas digital teknik oftast, men de antas på ett reaktivt sätt som saktar ner digital transformation av maskinentreprenadbranschen. Avslutningsvis visar denna studie att det finns flera aspekter av yrkesidentitet att överväga och ger en omfattande förståelse för det ömsesidiga beroendet mellan elementen i yrkesidentitet.

Indiana University-Purdue University Indianapolis (IUPUI) / In this thesis, an explicit time integration code which integrates multibody dynamics and the discrete element method is used for modelling the excavation and moving operation of cohesive soft soil (such as mud and snow) by bulldozers. A soft cohesive soil material model (that includes normal and tangential inter-particle force models) is used that can account for soil compressibility, plasticity, fracture, friction, viscosity and gain in cohesive strength due to compression. In addition, a time relaxation sub-model for the soil plastic deformation and cohesive strength is added in order to account for loss in soil cohesive strength and reduced bulk density due to tension or removal of the compression. This is essential in earth moving applications since the soil that is dug typically becomes loose soil that has lower shear strength and lower bulk density (larger volume) than compacted soil. If the model does not account for loss of soil shear strength then the dug soil pile in front of the blade of a bulldozer will have an artificially high shear strength. A penalty technique is used to impose joint and normal contact constraints. An asperity-based friction model is used to model contact and joint friction. A Cartesian Eulerian grid contact search algorithm is used to allow fast contact detection between particles. A recursive bounding box contact search algorithm is used to allow fast contact detection between the particles and polygonal contact surfaces. A multibody dynamics bulldozer model is created which includes the chassis/body, C-frame, blade, wheels and hydraulic actuators. The components are modelled as rigid bodies and are connected using revolute and prismatic joints. Rotary actuators along with PD (Proportional-Derivative) controllers are used to drive the wheels. Linear actuators along with PD controllers are used to drive the hydraulic actuators. Polygonal contact surfaces are defined for the tires and blade to model the interaction between the soil and the bulldozer. Simulations of a bulldozer performing typical shallow digging operations in a cohesive soil are presented. The simulation of a rear wheel drive bulldozer shows that, it has a limited digging capacity compared to the 4-wheel drive bulldozer. The effect of the relaxation parameter can be easily observed from the variation in the Bulldozer's velocity. The higher the relaxation parameter, the higher is the bulldozer's velocity while it is crossing over the soil patch. For the low penetration depth run the bulldozer takes less time compared to high penetration depth. Also higher magnitudes of torques at front and rear wheels can be observed in case of high penetration depth. The model is used to predict the wheel torque, wheel speed, vehicle speed and actuator forces during shallow digging operations on three types of soils and at two blade penetration depths. The model presented can be used to predict the motion, loads and required actuators forces and to improve the design of the various bulldozer components such as the blade, tires, engine and hydraulic actuators.

Many industries are today facing the possibilities and challenges arising with an increasingly digitalised world. One such is the scantily studied industry of earth-moving contractors that today stands in front of an increasing amount of digital technologies, which may have the possibility to assist firms in their earthwork operations. However, there are indications that many firms tend to experience difficulties to beneficially adopt or see the potential of utilising these digital technologies. Hence, many firms tend to undertake an adoption approach that is associated with high client dependency and a less beneficial unsustainable subordinated position within the industry’s value chain. The purpose of this study has thus been to explore how the technological, organisational and external elements affect earth-moving contractors’ opportunity to adopt and utilise digital technologies in their operations. Moreover, the study has aimed to contribute with the understanding and knowledge of how the adoption of digital technology can be used to strengthen Swedish contractors’ position in the earth-moving industry’s value chain and in the end, aid the country’s sociotechnical development. The findings of the study are based on an explorative multiple case study approach and extensive review of literature. The results suggest that the extent to which adoption and utilisation of digital technologies differs among different earth-moving firms. Three of the five studied companies are considered as digital forerunners which have been able to leverage digital technologies to increase efficiency in their operations. In the case of two of these firms, the adoption of digital technology has enabled them to transform their whole businesses and partake in an increased and more beneficial role within the value chain. Further, the analysis of the findings indicates that the difference in adoption is affected by several factors related to a continuous interaction between (1) the internal aspects of the organisations, (2) the external context of the firms and (3) if the technical features of the digital technologies are perceived as compatible and beneficial for, the current business process and strategy. The thesis contributes to academia with explorative findings within a scarcely studied industry in general and, regarding digital technology adoption in particular. Additionally, the study provides examples of the previously unrecognised industry-dynamic phenomena of value chain integration by earth-moving contractors. These findings could have implications for the whole construction sector in Sweden. Lastly, the study exemplifies opportunities and barriers crucial for the adoption and implementation of digital technologies within smaller project-based organisations. / Många branscher och industrier idag står inför utmaningarna och möjligheterna som uppstår i en allt mer digitaliserad värld. Ett tydligt exempel är maskinentreprenadsbranschen som idag ställs inför valet att införa nya och alltmer avancerade digitala verktyg som har möjlighet att främja deras operativa verksamheter. Dock finns indikationer att många företag har svårigheter att tillämpa och anamma dessa verktyg på ett gynnsamt sätt och är beroende av deras kunders agerande för aktivering av dessa. Studiens syfte har således varit att undersöka hur relationen mellan teknologiska, organisatoriska och externa faktorer påverkar maskinentreprenörernas möjligheter att aktivera och nyttja digitala teknologier i deras operativa verksamheter. Vidare har studien varit ämnad åt att bidra till en ökad förståelse och kunskap för hur digitala teknologier kan användas för att stärka maskinentreprenörernas position i värdekedjan för att slutändan främja Sveriges sociotekniska samhällsutveckling. Rapportens resultat bygger på en explorativ flerfallsstudie samt en gedigen litteratursökning. Resultaten visar på skillnader i hur digitala tekniker har tillämpats och används bland olika maskinentreprenörer. Tre av studiens fem fallföretag är digitalt framstående och har strategiskt tillämpat digital teknik som gett upphov till kraftig effektivitetsökning. Två av dessa företag har dessutom lyckats med en gynnsam ompositionering i värdekedjan som dessa befinner sig i, som ett resultat av anammandet av ny digital teknik. Vidare påvisar studiens analys av resultaten att möjligheten för aktivering av digitala teknologiska innovationer påverkas av ett kontinuerligt förändrande samspel mellan (1) maskinentreprenörernas organisatoriska egenskaper, (2) externa omständigheter samt (3) huruvida den digitala teknologins tekniska attribut uppfattas som kompatibla och fördelaktiga med nuvarande affärsverksamhet och strategi. Rapporten bidrar akademiskt med värdefull och explorativ empiri till en industri med en bristande mängd av forskning generellt, och i synnerhet gällande utnyttjandet samt tillämpandet av nya digitala teknologier. Dessutom bidrar studien med exempel och insikter om ett industridynamiskt fenomen, som tidigare ej uppmärksammats, i form av maskinentreprenörers förmåga att förflytta sig i värdekedjan. Dessa strukturella förändringar kan få konsekvenser för den svenska byggindustrin. Slutligen exemplifierar studien avgörande möjligheter och barriärer för införandet av digitala teknologier i mindre projektbaserade organisationer.