The construction equipment industry is developing at a fast pace, increasing the expectation on the next-generation machines. Wheel loaders and backhoe loaders are part of this evolution and all subsystems in those machines need to be developed to meet the high demands in energy eciency and productivity. One of the most important parts of the wheel loader is the loading unit. This is traditionally designed using highly experienced engineers and CAD software. To simplify the early stages of this process was an optimization tool developed to generate a design outlay. The optimization will minimize the mass of the linkage since unnecessary weight will lower the eciency. The minimum can be found by moving the joints and adjusting the shape of the device. The optimization will also include constraints to assure the correct performance of the linkage. Since there are a high number of design variables, a gradient-based optimization method was used. A finite element solver was also implemented to calculate the forces and stresses in the linkage. The linkages studied in this report are one from a typical wheel loader and one from a backhoe loader. Since these machines are extremely versatile, and used formany diferent tasks, two sets of constraints are compiled. One of the constraint sets yields a linkage suitable for machines only equipped with bucket, while the other results in an all-round linkage suitable for most tools and applications. The optimized linkages are compared to existing devices. The results show that there are some improvements possible and that the software could be used to help designers. However, the optimization problem is hard to solve due to non-smooth constraints functions and numerical instabilities. This issue could be overcome by diferent means, like using automatic diferentiation, a non-gradient based optimization method, decreasing the number of constraints or decreasing the number of design variables. / Utvecklingen av anlaggningsmaskiner sker i snabb takt och detta ökar förväntningarna på framtidens maskiner. En stor andel av alla anläggningsmaskiner är hjullastare och traktorgrävare och alla delsystem på dessa maskiner måste följa med i utvecklingen. En av de viktigaste delarna pa en hjullastare ar lastaggregatet. Det designas traditionellt med hjälp av CAD mjukvara och mycket erfarna konstruktörer. För att underlätta denna process har en optimeringsrutin utvecklats, som generarar ett designförslag. Optimeringen minskar länkagets massa genom att fytta lagringspositioner och ändra delarnas dimensioner. Detta ökar efektiviteten hos maskinen eftersom den slipper köra runt på onödig vikt. Optimeringen innehåller även villkor för att säkerställa god prestanda hos det optimerade aggregatet. Eftersom det ingår väldigt många designvariabler i optimeringen används en gradientbaserad metod. En finita element approximation används for att beräkna krafter och spänningar i länkaget. De länkage som undersöks i detta projekt är ett typsikt hjullastaraggregat och ett typiskt traktorgrävaraggregat. Eftersom dessa maskiner ar väldigt mångsidiga sammanställdes två olika uppsättningar av villkor. Den ena uppsättningen används för att optimera ett aggregat som endast ska användas med skopa, medan den andra uppsättningen används för att ta fram ett mer mångsidigt aggregat avsätt for att kunna klara av de flesta situationer och verktyg. De optimerade lastaggregaten är jämförda med produktionsaggregat och det visar sig att vissa förbättringar är möjliga. Slutsattsen är att optimeringsrutinen kan bli ett bra hjälpmedel for konstruktörer men att den behöver lite mer veriering. Villkorsfunktionen som optimeringen måste lösa är inte helt slät vilket är ett problem för en gradientbaserade metod och dessutom finns vissa numeriska instabiliteter. Dessa svårigheter kan undkommas pa olika sätt, t.ex. genom att använda automatisk derivering,byta optimeringsalgoritm, minska antalet villkor eller minska antalet variabler.

In this thesis a model is developed for calculating the loads on the wetclutches in apowershift transmission. This thesis was done at Volvo CE in Eskilstuna and is focusedon their 4-speed countershaft transmissions. The goal of the project is to be able tocalculate the loads automatically during the transmission tests and thus acquire increasedknowledge about what occurs during operation.The model was developed by first generating a number of concepts and then evalu-ating them to decide which one should be developed further. The chosen concept wasthen developed further and implemented into the test equipment as a calculation script.The chosen loads to model were the energy absorbed in each clutch, the coefficient offriction (COF) and the slip distance. The COF was later found to give too unreliableresults to be used in any other way than as a benchmark for how well the model wasconfigured and to see any large changes in COF.The model was validated by calculating the energy absorbed in a HTE-200 seriestransmission and comparing it to a reference calculation model. It was seen that theresults from the new model are very close to the reference result. The energy lostcalculated by the new model will be equal to 94 % of the energy lost calculated by thereference model, but only when measuring the inertia phase. The energy lost is equalto 135 % when the torque phase is included. The increasing difference is believed tobe because of an error in the reference model that means it does not cover the torquephase.

This thesis performed on master level covers an assignment given by the cab division at Volvo Construction Equipment (Eskilstuna, Sweden). The thesis has been carried out by Josefin Hult during the period 2014-01-23 to 2014-05-30 at Mälardalen University. Volvo Construction Equipment manufactures products including wheel loaders, backhoe loaders and articulated haulers. The assignment involves developing the standard door for larger wheel loaders. The current door has a welded frame surrounding the glass that is considered outdated and not cost effective. Volvo Construction Equipment wishes that the door was made in glass in a greater extent. The aim of the assignment has been to generate concepts regarding a glass door that fulfills given requirements. Three research questions have been stated and answered during the process. The product development process has consisted of three phases: information gathering, concept development process and development of detailed concept. For example, field studies and benchmarking have been performed to gather information about competitors’ products and the manufacturing and assembling of the current door. Concepts for handrails, sealant and overall door design have been generated in an iterative process. All components of the door have been developed into a detailed concept during the last phase of the process. The process has resulted in a frameless glass door. The concept suggestion consists of; a tempered sheet of glass, a clip list (sealant) that covers the edges of the glass, two different handrails, inner and outer handles, a gas spring, components to attach handrails against the glass, a cover and a lock mechanism. The major conclusion that is drawn is that it is fully possible to develop a door made in glass in a greater extent than the current door. Many competitors have machines where the door is made in glass in a large extent. This makes it believable that the glass door also will be perceived as timely and more modern and clear. Recommendations have been developed if there is interest in further development. The recommendations include, among others, development of handrail and test of prototype to ensure that all requirements are fulfilled. Figures are produced by the author if not stated otherwise.

Idag är det möjligt att modellera de hydrauliska och mekaniska systemen hos en hjullastare. Det går även i viss omfattning att simulera omgivningen samt de förarkommandon som krävs för utförandet av en önskad uppgift. Däremot är det enda sättet att få reda på hur en förare kommer att uppleva maskinen, dess körbarhet, att bygga en fungerande prototyp och be en förare att testa den. Syftet med det här examensarbetet var att hitta en korrelation mellan förarens bedömningar och mätdata insamlade från en hjullastare under körning. Resultaten är sedan tänkta att användas i framtida simuleringar. Olika hjullastare testades av en grupp provförare och deras subjektiva bedömningar såväl som mätdata från hjullastarna samlades in. Slutsatsen är att det går till en viss del att förutsäga körbarheten från insamlade data om förarens körstil är känd. Då förarnas körstil skiljer väldigt mycket är det är inte möjligt att dra allmänna slutsatser om körbarheten. / Today it is possible to model all hydraulic and mechanical systems of a wheel loader. To an extent the surrounding environment and the operator input required for a desired operation can also be simulated. However the only way to determine how an operator will perceive the handling qualities, the operability, of the wheel loader is to assemble a working prototype and ask an operator to try it out. The purpose of this Master thesis was to find some correlation between the drivers’ opinions and data recorded from the machines during operation. The results are intended to be used in future simulations. Different machines were tested by a group of drivers and their subjective impressions, as well as measurements from the machines were collected. The findings from the analysis are that the operability can be determined to a certain extent if the driver’s behaviour is known. Because of the differences in the way the drivers operate the machine it has not been possible to draw any general conclusions.

The usage of a robotic simulator hasprovidedthe advantages of the efficientdevelopment and testing of robotics applications, saving time and resources and making easier publics demonstrations. This thesis project consists on the simulation of a wheel loader at an industrial environment inthe cycle of material handling. For the development of the Project have been used the Robot Operating System (ROS) and Gazebo frameworks which allows to reproduce the 3D map of the work site as well as the robotic wheel loaderand simulate it in a realistic way. The developed softwarealsoprovidesthemechanism to drive the wheel loader throughthereproduced terrain, to controlthe movement of the different articulated joints of the robot, to recompile information of the environmentthroughdifferent sensors (Laser, Odometry, GPS, IMU, etc) and to provide of a waypoint routes to the robot. Furthermore the simulator will be able to reproduce and integrate an asphalt plant modelto the scenario. Allowing an interaction with the wheel loader, this will transport gravel from the piles of the terrain to the pocket of the asphalt plant.

Volvo Construction Equipment is investigating the potential of hybrid wheel loaders. To determine if this new hybrid wheel loader concept is preferable from an environmental point of view to the latest G- series Volvo wheel loader, a comparative life cycle assessment (LCA) has been performed  on the Volvo L150G wheel loader and a hybrid wheel loader concept. The complete machines have been studied throughout their life cycle: raw material extraction, material processing, manufacturing processes, transportation, use phase, and end of life. In order to quantitatively assess the environmental impact of all lifecycle stages, five different environmental indicators have been used: global warming potential, abiotic resource depletion potential, acidification potential, eutrophication potential and ozone depletion potential. In addition, a sensitivity analysis and two weighting methods are used to interpret the results. The results show that a hybrid wheel loader concept reduces environmental impacts significantly compared to a conventional L150G, except the impact category ADP (element). Moreover, the use phase has by far the greatest impact within the life cycle, for most impact categories (90% of the total life cycle impact). A sensitivity analysis on use phase with impacts also showed the limitations for use in China. / Volvo Construction Equipment undersöker potentialen av hybrid hjullastare. För att avgöra om ett hybrid hjullastare koncept har fördelar ur miljösynpunkt jämfört med en G-serien Volvo hjullastare har en jämförande livscykelanalys (LCA) utförts på Volvo L150G hjullastare och ett hybrid hjullastarkoncept. De kompletta maskinerna har studerats under hela deras livscykel: utvinning av råmaterial, materialbearbetning, tillverkningsprocesser, transport, användningsfas och slutet av skrotningsfasen. För att kvantitativt kunna bedöma miljökonsekvenserna av alla livscykelnskeden har fem olika miljöindikatorer använts: global uppvärmningspotential, abiotiska resursutarmningspotential, försurningspotential, övergödningspotential och ozonnedbrytingspotential. En känslighetsanalys och två viktningsmetoder har tillämpats för att tolka resultaten. Resultaten visar att ett hybrid hjullastarkoncept minskar miljöpåverkan avsevärt jämfört med en konventionell L150G, förutom påverkan från kategorin resursutarmningspotential. Dessutom har användningsprocessen i särklass störst påverkan inom livscykeln för de flesta effekt kategorier (90% av den totala livscykelpåverkan). En känslighetsanalys på användningsprocessen och dess effekter visade också på begränsningar för användning i Kina.

Welded structures susceptible to weld deformations require sequent processing to allow for mounting of precision components. This thesis includes a case study of the rear axle mount on a Volvo L220 wheel loader. A product development process was deployed in order to explore and evaluate alternative mounting methods such that manufacturing cost due to sequent processing could be decreased. Analysis of the frame variations showed any new concepts has to accommodate variations of up to $\delta z=-1.24\pm3.5$ mm. The product development process found two potential concept philosophies; transferring concepts which improves upon the current concept by transferring the processing away from the frame onto smaller components that are cheaper to process, and absorbing concepts that avoids sequent processing by absorbing the frame variations altogether. The transferring concept "Custom Plate" was selected for further development. The concept is based on the principals of reverse engineering by manufacturing a custom plate from a 3D surface map of the deformed mounting surface, placed between the frame and rear axle bridge, matching the surface geometry of both entities. The concept showed no apparent critical strength issues when simulated in CATIA V5. However, the economical gain of the concept is slim and depends heavily what spaces can be allocated for additional processing machinery. Suggestions for further development of the concept are given along with a discussion of improvements outside of the system boundary of the project, such as simulation of welds and welding sequence, and collection, storing, analysis, and visualisation of data.

This thesis was commissioned by Volvo Construction Equipment (Volvo CE) to redesign the front axle casing of their L90 wheel loader to be more in line with their larger wheel loaders. The current L90 front axle casing consists of two parts bolted together in the middle. However, the current assembly process is cumbersome, and as such, Volvo CE wants to determine if a one-piece front axle casing can be implemented into their L90 wheel loaders. Volvo CE’s larger wheel loaders such as the L120 currently have a one-piece design for the front axle casing and can serve as template. This thesis aimed to determine if it was possible to create a one-piece axle casing for the L90 and provide an example of how it would look like. Additionally, the suggested design would need to meet all of Volvo CE’s performance requirements and be on par with the current L90 front axle casing.  The methodology used to develop the redesigned axle casing consisted of performing different finite element analyses (FEA) in Ansys Mechanical to evaluate the casing’s performance. The analysis was preformed using Volvo CE’s guideline and performance criteria in order to determine what areas in the redesigned axle required further adjustment. Additionally, the redesigned casing would be compared against the current L90 casing. This would determine if the redesigned axle could be realistically implemented into a L90 wheel loader.  Applying this methodology led to three different iterations of the axle casing design. Each design iteration following the first one led to improvements in the casing’s mechanical performance. The third and final iteration was able to meet all of Volvo CE’s static and fatigue requirements. The stresses for the redesigned axle casing are, on average, 13% lower than that of the current axle casing at key points around the casing’s ribs. However, the tolerances required to manufacture the redesigned axle casing where slightly higher than the current L90 casing. Nevertheless, the tolerances required to manufacture redesigned axle can be realistically met by a foundry. This thesis was able to provide a plausible redesign that can be implemented in Volvo CE’s current line of L90 wheel loaders.

In this study we investigate the propagation of uncertainties in the input forces through a mechanical system. The system of interest was a wheel loader, but the methodology developed can be applied to any multibody systems. The modeling technique implemented focused on efficiently modeling stochastic systems for which the equations of motion are not available. The analysis targeted the reaction forces in joints of interest. The modeling approach developed in this thesis builds a foundation for determining the uncertainties in a Caterpillar 980G II wheel loader. The study begins with constructing a simple multibody deterministic system. This simple mechanism is modeled using differential algebraic equations in Matlab. Next, the model is compared with the CAD model constructed in ProMechanica. The stochastic model of the simple mechanism is then developed using a Monte Carlo approach and a Linear/Quadratic transformation method. The Collocation Method was developed for the simple case study for both Matlab and ProMechanica models. Thus, after the Collocation Method was validated on the simple case study, the method was applied to the full 980G II wheel loader in the CAD model in ProMechanica. This study developed and implemented an efficient computational method to propagate computational method to propagate uncertainties through "black-box" models of mechanical systems. The method was also proved to be reliable and easier to implement than traditional methods. / Master of Science

This paper presents an active component damage reducing control approach for driving manoeuvres of a wheel loader. For this purpose, the front and rear axle loads will be manipulated by force pulses induced into the machine chassis via the lifting cylinders of the function drive. The associated control approach is based on the principles of Reinforcement Learning. The essential advantage of such methods against linear control approaches is that no descriptive system properties are required, but the algorithm automatically determines the system behaviour. Due to the high number of necessary training runs, the algorithm is designed and taught using a validated wheel loader simulation model. After over 850 training runs, an optimal strategy for damping the axle loads could not yet be determined. In spite of the unprecedented convergence, initial improvements of the damage values have already been achieved on tracks that deviate from the training track. Some of these results show a 4.9 % lower component damage compared to a machine setting with no damping system. The results and limits of this strategy are discussed due to a comparison with other scientific active vibration damping approaches. Currently, a linear control method (P-PI-controller) has a higher damage reduction potential, but it is expected that further training runs and another learning algorithm could make the reinforcement learning approach even more effective. Coupling the linear control method with the selflearning approach shows the highest potential for the axle damage reduction.