Dissertations / Theses: 'Wheel'

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Corominas, Hife Kensell Kyle. "Four Wheel Steering : Comparison with two wheel steering." Thesis, KTH, Skolan för teknikvetenskap (SCI), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-153632.

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What are the differences between two wheel steering and four wheel steering? The aim of this project is to compare these two in terms of advantages gained from four wheel steering. A simulation is conducted on ADAMS Cars platform based on the RCV (Research Concept Vehicle) model, developed at KTH in Stockholm.

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Minda, Aditi. "The Wheel." Digital Commons at Loyola Marymount University and Loyola Law School, 2011. https://digitalcommons.lmu.edu/etd/70.

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Morini, Matteo. "Solar Wheel." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2021.

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L'elaborato tratta una particolare ruota solare prodotta da Marand, usata per le competizioni automobilistiche solari. Dopo un'introduzione, che spiega chi è Marand, in cosa consiste la ruota a grandi linee e gli aspetti generali di cui tenere conto, segue una descrizione dei componenti principali che formano la ruota ed infine la procedura per smontarla/montarla.

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Silva, Seth F. "Applied System Identification for a Four Wheel Reaction Wheel Platform." DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/328.

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Applied System Identification for a Four Wheel Reaction Wheel Platform By Seth Franklyn Silva At the California Polytechnic State University, San Luis Obispo there is a four-wheel reaction wheel pyramidal simulator platform supported by an air-bearing. This simulator has the current capability to measure the wheel speeds and angular velocity of the platform, and with these measurements, the system identification process was used to obtain the mass properties of this simulator. A handling algorithm was developed to allow wireless data acquisition and command to the spacecraft simulator from a “ground” computer allowing the simulator to be free of induced torques due to wiring. The system identification algorithm using a least squares estimation scheme was tested on this simulator and compared to theoretical analysis. The resultant principle inertia about the z-axis from the experimental analysis was 3.5 percent off the theoretical, while the other inertias had an error of up to 187 percent. The error is explained as noise attributed to noise in the measurement, averaging inconsistencies, low bandwidth, and derivation of accelerations from measured data.

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LEJDEBY, ANGELICA, and KARL HERNEBRANT. "Omni wheel robot." Thesis, KTH, Maskinkonstruktion (Inst.), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-191520.

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This project is about building a three wheeled robot car with Omni wheels. Omni wheels can make a robot drive sideways without rotating first. They can make a robot rotate at the same time as it goes straight ahead. An Omni wheel robot can for example be good choice for a tracking robot, though it can drive more effective than a robot car with regular wheels. The thing that speaks against Omni wheels is that it has more friction and it takes more power to rotate the wheels. This robot car is an obstacles avoiding robot that should with help of Ultrasonic sensors and IR-sensors be able to drive around in a room without crashing in to objects or walls. With the help of Omni wheels the robot should drive without rotating much which makes it more effective than a robot car with regular wheels.
Det här projektet handlar om att bygga en trehjulig robotbil med Omnihjul. Omnihjul kan göra det möjligt för en robot att köra i sidled utan att först rotera. De kan också möjliggöra för en robot att rotera samtidigt som den kör rakt fram i en rak linje. En Omnihjulrobot kan till exempel vara ett bra val som spårningsrobot. För att den kan köra mer effektivt än en robotbil med vanliga hjul. Det som talar mot Omnihjul är att de har mer friktion och det krävs mer kraft för att rotera hjulen. Den här robotbilen är en hinderundvikande robot som med hjälp av Ultraljudssensorer och IR-sensorer ska kunna köra runt i ett rum utan att krasha in i objekt eller väggar. Med hjälp av Omnihjul ska roboten kunna köra utan att rotera mycket, vilket gör den mer effektiv än en robotbil med vanliga hjul.

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Logan, Jeffery Jay. "Control and Sensor Development on a Four-Wheel Pyramidal Reaction Wheel Platform." DigitalCommons@CalPoly, 2008. https://digitalcommons.calpoly.edu/theses/27.

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The Pyramidal Reaction Wheel Platform, or PRWP, is used to simulate three-axis controls in a torque free space-like environment. The primary purpose of the system will be to evaluate the effects of conjoining sensors to maximize pointing accuracy. Furthermore, the system will incorporate a star tracker in conjunction with a Simulated Star Field (SSF) to better estimate the PRWP orientation. For the sake of this document, however, the goal is to implement a gyroscope, wheel rate sensors, and a make-shift accelerometer—to the PRWP—and integrate a controls algorithm such that three-axis controls are achieved for the PRWP. Three sensors were either better integrated into the system or added altogether. Tachometers were created as a form of hardware circuitry to measure each wheel rate with an accuracy of approximately 2.5 Hz (nearly 15 radians per second). The TAC board circuitry converted each motors encoder output into a speed by use of a frequency to voltage converter. Additionally, although three gyroscopes had been implemented previously, the system was better incorporated into the model such that it was directly transformed via a ROBOSTIX ADC converter before being relayed to SIMULINK via a Bluetooth link. The MEMS gyroscopes allowed for very accurate rate measurements—with a minimum resolution of approximately 0.25 radians per second. Finally, a makeshift accelerometer was incorporated into the system for the purpose of system identification. The accelerometer was incorporated into the system by utilizing a discrete time derivative of the gyroscope readings. However, thankfully a system of two accelerometers can be later utilized to achieve an accuracy of approximately 6 degrees per second-second in the x-axis and 2-3 degrees per second-second in the y- and z-axes. A controls test was performed where the starting location was qo=[0, 0, sqrt(2)/2, sqrt(2)/2] and the target location was qc=[0, 0, 0, 1]. At 80 seconds, the pointing accuracy was 70 degrees around the target and the system was unable to settle during the 80 second trial. The inaccuracy was because of the low frequency of operation of the system—1 Hz. Additionally, the platform reacts slowly to sensor readings and commands. The coupling of these issues causes the pointing accuracy to high. Furthermore, through experimental testing, the maximum wheel rate was found to be approximately 6400 RPM at a duty cycle of 50% at an 8000Hz PWM application due to the Pololu MD01B design limitations: low voltage range (up to 16V), low limit current limiter (5A), and high susceptibility to overheating for large currents.

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Baker, Brittany S. M. Massachusetts Institute of Technology. "Reconfigurable wheels : re-inventing the wheel for the next generation of planetary rovers." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/71459.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2012.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 84-85).
Experiences with Spirit and Opportunity, the twin Mars Exploration Rovers, showed that one of the major issues that needs to be addressed in order to expand the exploration capabilities of planetary rovers is that of wheel traction. The relationships governing how much traction a wheel can produce are highly dependent on both the shape of the wheel and terrain properties. These relationships are complex and not yet fully understood. The amount of power required to drive a wheel is also dependent on its shape and the terrain properties. Wheel sizes that tend to maximize traction also tend to require more power. In the past, it has always been a challenge to find the right balance between designing a rover wheel with high traction capabilities and low power requirements. More recently, researchers invented the idea of a reconfigurable wheel which would have the ability to change its shape to adapt to the type of terrain it was on. In challenging terrain environments, the wheel could configure to a size that would maximize traction. In less challenging terrain environments, the wheel could configure to a size that would minimize power. Theoretical simulation showed that the use of reconfigurable wheels could improve tractive performance and some initial prototyping and experimental testing corroborated those findings. The purpose of this project was to extend that prototyping and experimenting. Four reconfigurable wheels were designed, built, and integrated onto an actual rover platform. A control methodology whereby the wheels could autonomously reconfigure was also designed, implemented, and demonstrated. The rover was then tested in a simulated Martian environment to assess the effectiveness of the reconfigurable wheels. During the tests, the power consumption and the distance traveled by the rover were both measured and recorded. In all tests, the wheels were able to successfully reconfigure and the rover continued to advance forward; but as was expected, the reconfigurable wheel system consumed more power than a non-reconfigurable wheel system. In the end, the results showed that if maximizing vehicle traction was weighed more heavily than minimizing power consumption, the use of reconfigurable wheels yielded a net gain in performance.
by Brittany Baker.
S.M.

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Telliskivi, Tanel. "Wheel-rail Interaction Analysis." Doctoral thesis, KTH, Machine Design, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3532.

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A general approach to numerically simulating wear in rollingand sliding contacts is presented in this thesis. A simulationscheme is developed that calculates the wear at a detailedlevel. The removal of material follows Archards wear law,which states that the reduction of volume is linearlyproportional to the sliding distance, the normal load and thewear coefficient. The target application is the wheel-railcontact.

Careful attention is paid to stress properties in the normaldirection of the contact. A Winkler method is used to calculatethe normal pressure. The model is calibrated either withresults from Finite Element simulations (which can include aplastic material model) or a linear-elastic contact model. Thetangential tractions and the sliding distances are calculatedusing a method that incorporates the effect of rigid bodymotion and tangential deformations in the contact zone.Kalkers Fastsim code is used to validate the tangentialcalculation method. Results of three different sorts ofexperiments (full-scale, pin-on-disc and disc-on-disc) wereused to establish the wear and friction coefficients underdifferent operating conditions.

The experimental results show that the sliding velocity andcontact pressure in the contact situation strongly influencethe wear coefficient. For the disc-on-disc simulation, therewas good agreement between experimental results and thesimulation in terms of wear and rolling friction underdifferent operating conditions. Good agreement was alsoobtained in regard to form change of the rollers. In thefull-scale simulations, a two-point contact was analysed wherethe differences between the contacts on rail-head to wheeltread and rail edge to wheel flange can be attributed primarilyto the relative velocity differences in regard to bothmagnitude and direction. Good qualitative agreement was foundbetween the simulated wear rate and the full-scale test resultsat different contact conditions.

Keywords:railway rail, disc-on-disc, pin-on-disc,Archard, wear simulation, Winkler, rolling, sliding

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Navas, Medrano Samuel. "Autonomous Wheel Loader Simulator." Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-38053.

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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.

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Gerasimoff, Steven (Steven A. ). "Open wheel racecar steering." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/112590.

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Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.
Cataloged from PDF version of thesis.
Includes bibliographical references (page 36).
The steering system of a rear wheel drive open wheel racecar is the only directional control the driver possesses while driving. Steering linkages must be carefully designed to allow cars to navigate turns without exhausting the driver. Motorsports vehicles are designed to make tight turns while maximizing tire grip to maintain higher velocities in corners. Steering geometry must be optimized not only for car performance, but also to maximize driver comfort and improve the "feel" of the vehicle. In competitive motorsports, the steering system is critical to vehicle performance: an incorrectly designed system can at best cost a few fractions of a second on the track, and at worst cause severe driver injury. In the Formula SAE competition, student teams are tasked with designing and manufacturing all subsystems of a racecar for an annual competition while balancing safety, cost, and performance. This thesis will introduce fundamentals of steering system design, and will document in detail the design, analysis, manufacture, and testing of the 2017 MIT FSAE steering system.
by Steven Gerasimoff.
S.B.

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Gräsberg, Pontus, and Bill Lavebratt. "Reaction Wheel Stabilized Stick." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-264481.

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Control theory can be used to make an unstable system stable. This thesis seeks to do this, where the system is a two DOF inverted pendulum with reaction wheels for stabilisation. The thesis also seeks to answer what is most important for making it stabilize for a longer period of time. It was decided that a state space controller was to be used with various sensors measuring the states. To be able to design a functioning demonstrator, a mathematical model of the system dynamics was developed. In the end the demonstrator proved to function as desired, being able to balance indefinitely. It was found that it is absolutely necessary to either give the controller a perfect set point or to implement an automatic set point.
Reglerteknik kan användas för att göra ostabila system stabila. Målet med detta projekt var att göra detta med ett system i form av en inverterad pendel med två frihetsgrader som balanseras med hjälp av två svänghjul. Projektet söker att besvara frågan om vad som är de viktigaste faktorerna för att få systemet att vara stabilt över en längre tid. En tillståndsåterkoppling användes som regulator vilket innebar att flera olika sensorer behövdes för att mäta de olika tillstånden. För att kunna konstruera en fungerande prototyp utvecklades en matematisk modell av systemet vilken användes för simulering av systemet. Till slut konstruerades en fungerade prototyp som till synes kunde balansera över oöverskådlig tid. En av de faktorer som visade sig påverka huruvida systemet uppnår stabilitet över längre tid var hur bra referenspunkt som gavs till regulatorn, det vill säga det tillstånd som regulatorn reglerar systemet mot. Det visade sig vara möjligt att implementera en självjusterande referenspunkt som gjorde systemet stabilt över tid.

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Hwang, Choal Hee. "The wheel of rebirth." The Ohio State University, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=osu1327603492.

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Hamnholm, Löfgren Teodor. "Wheel Brake Noise Analysis." Thesis, Linköpings universitet, Reglerteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-138011.

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The scope of this thesis is to investigate methods of recording, processing and analysing sound data from wheel brake testing in dynamometers with focus on detecting and measuring squeal. The desired outcome is a method that Scania can use to record and analyse brake sound. A literature study was made to find relevant methodologies and tools proposed in papers, books and industry standards. These methods were tried and evaluated by recording and analysing real sound data and other signals from one of Scanias dynamometers. The resulting method includes directions on what hardware to use, how to set it up and an algorithm that computes a spectral limit based on normal sound data. This limit is then used as reference when evaluating other recordings. To increase signal to noise ratio, an adaptive filter is proposed to attenuate background noise in the recordings, in particular from the dynamometer and ventilation system. The conclusion is that it is possible to find squeal using spectral limits based on normal data. The performance of the algorithm is a compromise between being very effective but rather complex, or slightly less effective but also less complex. Its performance is also highly dependent on how squeal is defined. A very narrow definition will only find certain types of squeal while a more broad definition will find more squeal, but also potentially mislabel some recordings.

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Fields, Travis D. "The development and optimization of a teleoperated four-wheel drive/four-wheel steer vehicle." abstract and full text PDF (UNR users only), 2009. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1472952.

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Jones, Emil. "All purpose physics wheel class." Thesis, University of Kalmar, School of Communication and Design, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hik:diva-902.

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Detta arbete beskriver hur processen för att skapa en generell hjulklass har gått till. Klassen skall skapas med hjälp av fysikmotorn Bullet. Den generella hjulklassen skall användas som en komponent i Craft Animations fordonssimuleringar. Det finns stöd för 3 olika former av hjulupphängning. Oberoende hjul medkollisionskroppar, Länkade hjul med kollisionskroppar samt Hjul med strålföljning. Rapporten visar hur konstruktionen av dessa hjulupphängningar går till. Slutligen görs en sammanställning där de olika teknikerna diskuteras och jämförs.

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Yeung, Nai Chi Psychology Faculty of Science UNSW. "Stereotype threat behind the wheel." Awarded by:University of New South Wales. School of Psychology, 2006. http://handle.unsw.edu.au/1959.4/26242.

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Stereotype threat refers to the pressure that individuals feel when they are at risk of confirming a demeaning stereotype about themselves. Research has found that stereotype threat impairs performance on cognitive-based tasks by inducing mental interference (e.g., Schmader & Johns, 2003). This thesis hypothesised that this finding would generalise to driving and that drivers who are better able to inhibit cognitive interference (i.e., with better inhibitory ability) would be less susceptible to the disruptive effect of stereotype threat than drivers who are less able (i.e., with poorer inhibitory ability). A series of three experiments conducted in a driving simulator tested the predictions using the gender stereotype of driving skills and investigated the interpretation of the results. The experiments revealed that stereotype threat exerted both a facilitative and debilitative influence on driving performance, as indicated by different performance measures. The facilitative effect diminished when drivers experienced increased mental demands or when they were assessed by an unexpected performance measure, while the debilitative effect was more likely observed among drivers who received negative feedback than drivers who received positive feedback. Moreover, the results supported the prediction that inhibitory ability would moderate the detrimental impact of stereotype threat as the performance of drivers with poorer inhibitory ability was impeded more than that of drivers with better inhibitory ability. Regarding the processes underlying the present findings, the experiments provided suggestive evidence that stereotype threat elicits cognitive interference and simultaneously motivates drivers to concentrate on particular performance areas in an attempt to refute the stereotype. In combination, these processes appear to be at least partly responsible for the performance deficits and boosts observed.

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Barlow, N. "High-rate grinding wheel design." Thesis, Liverpool John Moores University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380664.

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Kienhöfer, Frank Werner. "Heavy vehicle wheel slip control." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609594.

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Beller, Philip. "FLUX : Rethinking two-wheel mobility." Thesis, Umeå universitet, Designhögskolan vid Umeå universitet, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-171771.

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This project has investigated how to reshape two-wheel mobility in a more functional driven way, without losing the thrill of riding a motorcycle. The intitial cue was offered by the current rise of electric powertrains in the market. The opportunity of finding new spaces in the existing motorcycle architecture that could increase it's functionality and safety served as inspiration for this project. By achieving these steps this project wishes to envision a product that can attract new audiences whilst making two-wheel mobility more accessible. The process involved a variety of techniques that range from concept creation to 3D visualisation. During the ideation phase digital and analogue sketching techniques were combined after benchmarking existing products and visualising through animations possible solutions. In a later step the design was refined using digital painting in addition to polygon modelling. It has been helpful to evaluate the product in VR through various steps of the process, this provided a better understanding of the volumes and enabled a more accurate design of certain components. The result of the project is Flux. Combining unusual materials, like silicone, with a new layout offered the possibility of creating a simple yet advanced solution that provides various benefits to riding in everyday life. These benefits range from an enhanced cargo capability to an easier way to swap or recharge the batteries. In addition, it features some seamlessly integrated technology improvements that are vowed to make riding safer, without compromising on the experience.

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Korhonen, Daniel. "Wheel alignment method feasibility study." Thesis, KTH, Fordonsdynamik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-280555.

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Throughout the history of motor vehicles, the tyres have always been consideredas one of the most important components of the vehicle due to their interactionwith the road. One important aspect is the wheel alignment, with the purposeto adjust the static wheel angles that are essential for many reasons, such assafety and fuel consumption for instance. Despite the numerous methods forwheel angle measurements, there seems to be no existing technical solutionbased on computer vision, that is suitable for residential use, regarding bothcost and size of the equipment. The study aims to investigate the feasibility ofsuch a system.The proposed system is based on planar fiducial markers called ArUco.From images or video frames of the marker, the pose of the marker can beestimated. Thus, by placing such markers on the ground, on the wheel andon the vehicle, the estimated pose of the markers can be used to measure andcalculate the wheel alignment parameters. Only toe and camber angles aremeasured within the scope of this thesis, even if the system has the potential tomeasure other wheel alignment parameters as well.After camera calibration, simplified ArUco marker tests were done by measuringthe known displacement and inclination of a marker with respect to areference marker. The mean absolute error was 030400 and 0:024mm for theinclination angle and displacement, respectively. Furthermore, the toe and camberangles of a vehicle were measured and compared to reference measurementsperformed with a commercial wheel alignment system, giving mean absoluteerrors of 0520 and 0280 for the camber and toe angles, respectively. Despitethe relatively large errors for the toe and camber angle measurements, theresults from the initial inclination and displacement tests show the potential ofthe system. In addition, several error sources and suggestions for improvementcan be identified.As a conclusion, the proposed system can be considered a working firstprototype, which after improvement and optimisation has the potential tobecome a feasible alternative, especially for residential use and for mobileworkshops due to the low cost, size and usability of the system.
Inom fordonstekniken har däcken alltid betraktats som en av fordonets viktigastekomponenter på grund av deras interaktion med vägen. En viktig aspektär hjulinställning, med syftet att justera de statiska hjulvinklarna som är viktigaav många anledningar, som exempelvis säkerhet och bränsleförbrukning.Trots flera metoder för mätning av hjulvinklar verkar det inte finnas någonbefintlig teknisk lösning baserad på datorseende, som är lämplig för privat brukbåde gällande kostnad och storlek på utrustningen. Syftet med studien är attundersöka genomförbarheten för ett sådant system.Det föreslagna systemet är baserat på plana ArUco-markörer. Från bildereller bildrutor i en video av markören kan dess läge uppskattas. Genom attplacera sådana markörer på marken, på hjulet och på fordonet, kan såledesmarkörernas uppskattade lägen användas för att mäta och beräkna hjulvinklarna.Endast toe- och cambervinklar mäts inom ramen för detta examensarbete, ävenom systemet också kan mäta andra hjulvinklar.Efter kamerakalibrering utfördes enkla ArUco-markörtester genom att mätaden kända förskjutningen och vinkeln av en markör i förhållande till en referensmarkör.De genomsnittliga absoluta felen var 030400 och 0:024mm förvinkeln respektive förskjutningen. Vidare mättes toe- och cambervinklar påett fordon och jämfördes med referensmätningar utförda med ett kommersiellthjulinställningssystem. De genomsnittliga absoluta felen var 0520 och 0280för camber- respektive toevinkeln. Trots de relativt stora felen i mätningarnaav toe- och cambervinklar visar resultaten från de första testerna systemetspotential. Dessutom kan flera felkällor och förslag till förbättringar identifieras.Som en slutsats kan det föreslagna systemet betraktas som en fungerandeförsta prototyp, som efter förbättring och optimering har potential att bli ettmöjligt alternativ, särskilt för hemmabruk och för mobila verkstäder på grundav låga kostnader, systemets ringa storlek och användbarhet.

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Eriksson, Kathryn O. "Red lustrous wheel-made ware /." Jonsered : Paul Åströms Förlag, 1993. http://catalogue.bnf.fr/ark:/12148/cb36210492b.

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Bengtsson, Erik. "Concept Development of Stroller Wheel." Thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH, Industriell produktutveckling, produktion och design, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-44610.

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Gharib, Alireza. "FOUR SIMULTANEOUSLY STEERABLE WHEEL ROBOT." OpenSIUC, 2019. https://opensiuc.lib.siu.edu/theses/2500.

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Our whole purpose from this research is to come up with the best design of a robot which is capable of carrying the load and follow the most reliable and most efficient path in order to get to its destination. Previous research [1]is already done for a three and two wheel robot, however, we need a design which satisfies our specific requirement for higher reliability and ability to carry load in manufacturing environments or on different planets.

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Villella, Matthew G. "Nonlinear Modeling and Control of Automobiles with Dynamic Wheel-Road Friction and Wheel Torque Inputs." Thesis, Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/5198.

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This thesis presents a new nonlinear automobile dynamical model and investigates the possibility of automobile dynamic control with wheel torque utilizing this model. The model has been developed from first principles by applying classical mechanics. Inputs to the model are the four independent wheel torques, while the steer angles at each wheel are specified as independent time-varying signals. In this way, consideration of a variety of steering system architectures, including rear-wheel steer, is possible, and steering introduces time-varying structure into the vehicle model. The frictional contact at the wheel-road interface is modeled by use of the LuGre dynamic friction model. Extensions to the existing two-dimensional LuGre friction model are derived and the steady-state of the friction model is compared to existing static friction models. Simulation results are presented to validate the model mathematics and to explore automobile behavior in a variety of scenarios. Vehicle control with wheel torque is explored using the theory of input-output linearization for multi-input multi-output systems. System relative degree is analyzed and use of steady-state LuGre friction in a control design model is shown to give rise to relative degree singularities when no wheel slip occurs. Dynamic LuGre friction does not cause such singularities, but instead has an ill-defined nature under the same no-slip condition. A method for treating this ill-defined condition is developed, leading to the potential for the system to have relative degree. Longitudinal velocity control and combined longitudinal and angular vehicle velocity control are demonstrated in simulation using input-output linearization, and are shown to produce improved vehicle response as compared to the open-loop behavior of the automobile. Robustness of the longitudinal velocity control to friction model parameter variation is explored and little impact to the controller's ability to track the desired trajectory is observed.

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Westbom, Daniel, and Petter Frejinger. "Yaw control using rear wheel steering." Thesis, Linköping University, Department of Electrical Engineering, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-1463.

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The purpose of this project is to continue the work on a vehicle model developed in ADAMS/Car and applied with the concept of ACM (Autonomous Corner Module). The project is divided up in two parts. The objective of the first part is to setup a co-simulation environment between ADAMS/Car and MATLAB/Simulink, and evaluate the vehicle model. In the second part a yaw controller is developed using only the rear wheel steering possibilities. The controller will be evaluated when it is applied on the vehicle model.

The approach is to develop two models, one simpler in MATLAB/Simulink and one more complex in ADAMS/Car, and verify that they show similar behavior. The models will then be linearized and the control design will be based on the most appropriate linear model. Most of the work has been developing and evaluating the two vehicle models in ADAMS/Car and MATLAB/Simulink.

The result was a working co-simulation environment where an evaluation of two different controllers was made. Due to linearization of the ADAMS model was nsuccessful, the controllers were based on the simpler linear Simulink model. Both controllers show similar results. Tests on the ADAMS model showed that it is hard to control both the yaw rate and body slip only by rear wheel steering.

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Torstensson, Martin, and Hans Pettersen. "Optimization of front Wheel Arch Liner." Thesis, Linköping University, Department of Mechanical Engineering, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-5957.

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About ten years ago Volvo Cars could see that car manufactures began to introduce rear wheel arch liners made of non-woven fabrics or some kind of laminate which are mostly common today. Volvo Cars have also seen that competitors now are beginning to develop the front wheel arch liners more and more and expect a development equal to the one for the rear wheel arch liners. This is why we are set to optimize the front wheel arch liner.

For development of mechanical products such as car parts, a discursive method is most suitable to follow. For example systematical concept development which we have used in our work.

From a technical point of view, our results shows that the penta laminate used for the wheel arch liner on Mercedes Benz S-class is by far the best material. Unfortunately it is rather expensive which of course affects its result in a negative way when cost is taken in to consideration. When including cost, the solid plastic is actually rather economical.

After assessment of the result in total we are however convinced that Volvo Cars should concentrate on further research of penta laminate and open negotiations with different suppliers regarding a material of this kind.

Regarding the geometry, the tests and studies that Volvo Cars have performed earlier on splash shields clearly shows the usage of the part and further research done by our selves does not point at any problems with a splash shield integrated in the wheel arch liner.

För ungefär tio år sedan kunde Volvo Cars se att biltillverkare började introducera bakre hjulhus tillverkade av ”non-woven” fibrer eller någon form av laminat vilket idag är högst vanligt. Volvo Cars har också sett att konkurrenter nu börjar utveckla främre hjulhus mer och mer och räknar med en utveckling liknande den för bakre hjulhus. Detta är anledningen till att vi har fått uppgiften att optimera det främre hjulhuset.

För utveckling av mekaniska produkter så som bildelar, är en diskursiv metod mest lämpad att följa. Till exempel systematisk konceptutveckling som vi har valt att använda i vårt arbete.

Sett ur ett tekniskt perspektiv, visar våra resultat att pentalaminatet som används för hjulhusen på Mercedes Benz S-klass, är det överlägset bästa materialet. Tyvärr ar det ganska dyrt vilket naturligtvis påverkar dess resultat negativt när hänsyn tas till kostnader. När vi även ser till kostnaderna, är faktiskt den rena plasten mycket ekonomisk. Efter bedömning av det totala resultatet, är vi helt övertygade om att Volvo Cars borde koncentrera sig på fortsatta undersökningar av pentalaminat och inleda förhandlingar med olika underleverantörer angående material av denna typ.

Angående geometrin, visar Volvo Cars’ sedan tidigare genomförda tester och studier att en splash shield fyller en viktig funktion och vidare undersökningar genomförda av oss själva pekar inte på några problem med en i hjulhuset integrerad splash shield.

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27

Karlsson, Jan. "Analyzes of a wheel loader usage." Thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-11240.

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The wheel loader is a very versatile machine hence the layout of the machine and the software has to be a compromise of all the possible application. If the machine could detect the application and adapt the software settings to optimize the machine for the current application more application unique settings would be possible. To make the application identification cost efficient and possible to implement over the whole product range a minimum of added product cost is preferred. Therefore only using existing sensors of a wheel loader and using a software algorithm for the identification is suggested. In the following chapters three common applications are described from a generic point of view. The identification can be divided into different sections days, series, cycles and phases. The declaration of the phases is meant to be consistent regardless of application, however some phases may not be present in some application, 18 phases are identified to cover all application. Algorithms are developed to identify three different applications, bucket, pallet, timber and two different material classes. It is stated that it is possible to differentiate at least two different material classes with the suggested algorithms.

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28

Jenkins, Anne Elizabeth. "Operating the potter's wheel shaping faith /." Theological Research Exchange Network (TREN), 2006. http://www.tren.com/search.cfm?p068-0569.

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29

Berg, Johan. "Better design of wheel-loaded decks." Thesis, KTH, Marina system, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-119766.

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This study treats the design of secondary structures for wheel-loaded decks. It concludes that significant savings in structural weight, overall cost and environmental impact can be obtained by an improved design. The rules of three classification societies are examined and their principle differences are discussed. Weight and cost optimal solutions of rule-based design are identified for a deck of a typical short-sea RoRo-vessel. The rule-optimal designs are assessed and further improved on the basis of FEcalculations and the economic and environmental benefits associated with the best solutions are approximated.

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30

Kunz, Jacob Andrew. "Probabilistic modeling of microgrinding wheel topography." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/49118.

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This work addresses the advanced probabilistic modeling of the stochastic nature of microgrinding in the machining of high-aspect ratio, ceramic micro-features. The heightened sensitivity of such high-fidelity workpieces to excessive grit cutting force drives a need for improved stochastic modeling. Statistical propagation is used to generate a comprehensive analytic probabilistic model for static wheel topography. Numerical simulation and measurement of microgrinding wheels show the model accurately predicts the stochastic nature of the topography when exact wheel specifications are known. Investigation into the statistical scale affects associated microgrinding wheels shows that the decreasing number of abrasives in the wheel increases the relative statistical variability in the wheel topography although variability in the wheel concentration number dominates the source of variance. An in situ microgrinding wheel measurement technique is developed to aid in the calibration of the process model to improve on the inaccuracy caused by wheel specification error. A probabilistic model is generated for straight traverse and infeed microgrinding dynamic wheel topography. Infeed microgrinding was shown to provide a method of measuring individual grit cutting forces with constant undeformed chip thickness within the grind zone. Measurements of the dynamic wheel topography in infeed microgrinding verified the accuracy of the probabilistic model.

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31

Zhu, Yi. "Adhesion in the wheel-rail contact." Doctoral thesis, KTH, Tribologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-133342.

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To attract more customers and compete with other modes of transportation, railway transport needs to ensure safety, punctuality, high comfort, and low cost; wheel–rail adhesion, i.e., the transmitted tangential force in the longitudinal direction during driving and braking, plays an important role in all these aspects. Adhesion needs to be kept at a certain level for railway operation and maintenance. However, wheel−rail contact is an open system contact. Different contaminants can present between the wheel and rail surfaces, forming a third-body layer that affects the adhesion. Prediction of wheel–rail adhesion is important for railway operations and research into vehicle dynamics; however, this prediction is difficult because of the presence of contaminants. This thesis deals with wheel–rail adhesion from a tribological perspective. The five appended papers discuss wheel–rail adhesion in terms of dry conditions, lubricated conditions, leaf contamination, iron oxides, and environmental conditions. The research methodologies used are numerical modelling, scaled laboratory experiments, and field tests. The research objective is to understand the mechanisms of the adhesion loss phenomenon. A numerical model was developed to predict wheel–rail adhesion based on real measured 3D surfaces. Computer simulation indicates that surface topography has a larger impact on lubricated than on dry contacts. Plastic deformation in asperities is found to be very important in the model. Ball-on-disc tests indicate that water can give an extremely low adhesion coefficient on smooth surfaces, possibly due to surface oxidation. Investigation of lubricated contacts at low speed indicates that oil reduces the adhesion coefficient by carrying a normal load, while adhesion loss due to water depends on the surface topography, water temperature, and surface oxidation. A field investigation indicates that leaves reduce the friction coefficient because of the chemical reaction between leaves and bulk materials. The thickness of the surface oxide layer was found to be an essential factor determining adhesion reduction. Pin-on-disc experiments found a transition in the friction coefficient with regard to the relative humidity, due to a trade-off between the water molecule film and the hematite on the surface.

QC 20131031

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Garcia, Hector, and Emma Smith. "Wheel Induced Vibrations on Heavy Vehicles." Thesis, KTH, Skolan för teknikvetenskap (SCI), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-153927.

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Some of the most significant comfort disturbances in heavy vehicles can often be related to the wheels. In those cases, the vibration of the vehicle is excited by for example force variations within the tire, ovality of the tire or imbalance in the wheel. The disturbances are dependent on vehicle speed and are often perceived as most unpleasant at cruising speed on a motorway, at around 90 km/h. Truck manufacturers want to increase the robustness against this type of disturbance, since this results in an improved operator comfort. But it also makes it possible to lower the requirements on the suppliers of tires and rims, and thereby there is a financial gain for both customer and manufacturer. The aim with this project is to increase the understanding of wheel induced vibrations. In order to achieve this a literature survey has been performed on the subject. Furthermore, the phenomenon has been studied analytically by using a quarter car model which includes a brush tire model. The model is scripted in MATLAB. Simulations have been performed to analyse the effect on the chassis when forces excited by mass imbalance and radial run out are introduced. When looking at the second harmonic radial run out imperfection the unsprung mass, i.e the wheel, starts to bounce during the settling time. Also when comparing two different weights of a mass imbalance the power increase of the vibration in the sprung mass is much larger than the power increase of the unsprung mass at the specific frequency. This implies that the excitation frequency, the wheel rotation frequency in this case, is a harmonic repetition of the sprung mass undamped natural frequency. To avoid this phenomenon the undamped natural frequency of the sprung mass must change either by adding a damper or by changing the weight or the spring stiffness. The simulation is run with a damper although without it the power increase would be much larger.

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33

Yang, Sichao. "In-wheel motors for electric vehicles." Thesis, University of Newcastle upon Tyne, 2017. http://hdl.handle.net/10443/4054.

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The in-wheel motor technology as the source of traction for electric vehicles has been researched recently because it is compact and ease-to-integrate. The motor is housed in the wheel. Since the room for the motor is tightly defined by the size of the wheel and there is no gearing system, the motor must have a high torque density to drive the vehicle directly and a high efficiency to keep cool. The existing motor uses a surface-mounted magnet topology. To make it more cost-competitive, the magnet material needs to be reduced while maintaining the torque performance at the rated operating condition. It is the motive of this Ph.D. research. The thesis starts with a brief introduction on the background of the electric vehicle. Then the major challenges of the in-wheel motor technology are summarised. With the derived specifications, an induction machine and a switched reluctance machine are then simulated and analysed. Still, the permanent magnet synchronous machine is proved to have the highest torque density. Change from surface-mounted to interior topology, six new magnet topologies are investigated. The V-shaped interior magnet topology shows superior torque-to-magnet-mass ratio and is easy-to-manufacture. It gives 96% torque while using 56% of the magnet mass compared to the existing motor due to the assist from the additional reluctance torque and the lower magnetic circuit reluctance. The key to use less magnet mass while avoiding the demagnetisation is the front iron shielding effect. The analytical explanation on the better resistance to demagnetisation in the V-shaped motor is provided. The magnet loss mechanism is discussed for proper segmentation. Detailed design adjustments are made to compromise between the torque-to-magnet-mass ratio and the manufactural practicality. Issues regarding to lower mechanical rigidity occurred in initial assembly of the prototype and solutions are proposed. Followed by successful assembly, experimental tests were conducted and results show good agreement with the simulation. A specific form of torque ripple is found in the V-shaped motor and occurs generally in all fractional-slot concentrated-winding machines with saliency. It is explained by an analytical model. This model is also extended to explain the generally lower reluctance torque in vi fractional-slot concentrated-winding machines. Potential design improvements are suggested and simulated for future versions.

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Fagrell, William. "Optimization of a cutter wheel bearing." Thesis, Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-79051.

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This Master's thesis project was provided by Epiroc Rock Drills AB and conducted at Camatec Industriteknik AB in Karlstad, Sweden. The project is centered around the cutter wheel in the mechanical rock excavator Mobile Miner 40V. This cutter wheel is equipped with cutter discs that grind rock into debris as the wheel rotates and thrusts forward. The internal system consisting of a bearing constellation and the components in its vicinity has experienced a certain degree of wear in the form of scuffing and this was detected on the surfaces of some of the components in the system. The reasons for this occurrence are unknown and per the request of the thesis provider, this was to be determined. The thesis provider also requested a new Finite Element Analysis (FEA) model of the system along with feasible load cases that can be applied to said model. The project was deemed extensive and was therefore decided to be conducted by two students. This thesis covers the determination of the load cases as well as the optimization of the current design of the system inside the cutter wheel. During the pre-study, relevant background data was obtained for the cutter wheel and the internal system. Methods and models considered to potentially be useful were also gathered. The system in question was divided into two separate models; one consisted of a tribo-system with two components in sliding contact and the other consisted of the bearing constellation along with the outer-most section of the cutter wheel. The purpose of the first model was to use it to determine the contact pressure between the tribo-surfaces and by doing so, be able to determine the expected lubrication regime for the oil in the tribo-system. A material selection process was also conducted on the tribo-surface that had experienced the most severe surface damage. Additionally, minor reconstructions were made with the purpose of optimizing the system. The purpose of the second model was to apply the calculated load cases to the cutter disc attachments located on the outer-most section of the cutter wheel and then determine the contact pressures that develop on the bearing roller elements. The results of the thesis work consist of five potential material options, two reconstructions and 60 different load cases for the FEA model. With the load cases, the largest contact pressures on the bearing roller elements was determined. In addition, the cause of the severe surface damage that had occurred in the system is believed to have been identified. Further work on the project work is believed to be required. Future work of interest are determining load cases that incorporate multiple cutter discs simultaneously in contact with the rock, reconstruction solutions for the oil inlet and outlet pipes, a more thorough materials selection process and a criterion for the expected lubrication regime in the tribo-system based on tests performed with materials that are more identical to the ones in this project.
Detta examensarbete tillhandahölls av Epiroc Rock Drills AB och genomfördes hos Camatec Industriteknik i Karlstad, Sverige. Projektet är centrerat kring cutterhjulet i maskinen Mobile Miner 40V som är avsedd för mekanisk bergavverkning. Cutterhjulet är utrustat med cutter discar som maler berget till mindre flisor genom att hjulet roterar och trycks framåt. Det inre systemet bestående av en lagring med närliggande komponenter har utsatts för en viss grad av nötning i form av scuffing och detta upptäcktes på ytorna hos vissa av komponenterna i systemet. De bakomliggande anledningarna för denna förekomst är okända och utifrån begäran från projektgivaren skulle dessa anledningar fastställas. Projektgivaren eftersökte även en ny FEM-modell av systemet tillsammans med rimliga lastfall som ska kunna appliceras på modellen i fråga. Projektet ansågs tämligen omfattande och det bedömdes därför att två studenter krävdes för att genomföra arbetet. Denna uppsats behandlar framtagningen av lastfallen såväl som optimeringen av den nuvarande designen av systemet inuti cutterhjulet. Under förstudien hämtades relevant bakgrundsdata för cutterhjulet och det interna systemet. Metoder och teorier som ansågs vara potentiellt användbara samlades även in. Systemet i fråga delades in i två separata modeller; en bestod av ett tribo-system bestående av två tribo-ytor i glidande kontakt och den andra bestod av lagringen tillsammans med den yttersta sektionen hos cutterhjulet. Syftet med den förstnämnda modellen var att använda den för att bestämma kontakttrycket mellan tribo-ytorna, och genom detta kunna fastställa den förväntade smörjningsregimen hos oljan i tribo-systemet. En materialvalsprocess utfördes även för tribo-ytan som hade utsatts för den mest allvarliga skadan. Även smärre omkonstruktioner utfördes med syftet att optimera systemet. Syftet hos den andra modellen var att kunna applicera de beräknade lastfallen på cutter discarnas infästningar som återfinns i den yttersta sektionen hos cutterhjulet och sedan bestämma kontakttrycken som uppstår på rullarna i lagren. Resultaten från arbetet består av fem potentiella materialval, två konstruktionsändringar och 60 olika lastfall för FEM-modellen. Genom att applicera lastfallen bestämdes de största kontakttrycken på lagrens rullar. Utöver detta anses det att anledningen för den allvarliga ytskadan som hade skett i systemet har identifierats. Det anses att fortsatt arbete krävs för projektet. Kompletterande arbete som anses vara av intresse är lastfall som inkluderar flera cutter discar i ingrepp samtidigt med berget, konstruktionslösningar för tillförsel och bortförsel av oljan, en mer djupgående materialvalsprocess och ett kriterium för förväntad smörjningsregim hos tribo-systemet baserat på tester utförda med material som är mer identiska med dem som förekommer i projektet.

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35

Yu, Xu. "Tank-to-Wheel Energy Breakdown Analysis." Thesis, KTH, Fordonsdynamik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-280559.

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In early design phase for new hybrid electric vehicle (HEV) powertrains, simulation isused for the estimation of vehicle fuel consumption. For hybrid electric powertrains,fuel consumption is highly related to powertrain efficiency. While powertrainefficiency of hybrid electric powertrain is not a linear product of efficiencies ofcomponents, it has to be analysed as a sequence of energy conversions includingcomponent losses and energy interaction among components.This thesis is aimed at studying the energy losses and flows and present them in theform of Sankey diagram, later, an adaptive energy management system is developedbased on current rule-based control strategy. The first part involves developing energycalculation block in GT-SUITE corresponding to the vehicle model, calculating allthe energy losses and flows and presenting them in Sankey diagram. The secondpart involves optimizing energy management system control parameters according todifferent representative driving cycles. The third part involves developing adaptiveenergy management system by deploying optimal control parameter based on drivingpattern recognition with the help of SVM (support vector machine).In conclusion, a sturctured way to generate the Sankey diagram has been successfullygenerated and it turns out to be an effective tool to study HEV powertrain efficiencyand fuel economy. In addition, the combination of driving pattern recognition andoptimized control parameters also show a significant potential improvement in fuelconsumption.
Under den tidiga utvecklingsfasen av nya elektrifieradedrivlinor for hybridapplikationer (HEV) används simulering för uppskattning avfordonets bränsleförbrukning. För dess drivlinor är bränsleförbrukningen i hög gradkopplad till drivlinans verkningsgrad. Även om drivlinans verkningsgrad inte ären linjär prokukt av komponenternas verkningsgrad behöve rden analyseras somen sekvens av energiomvandlingar, inklusive förluster och energipåverkan mellankomponenter.Detta examensarbete syftar till att undersöka energiförluster och flöden samtpresentera dessa i form av sankey diagram. Senare utvecklas ett anpassningsbartenergihanteringssystem baserat på nuvarande regelbaserad kontrollstrategi. Deninledande delen involverar utvecklandet av energianalys i GT-SUITE som motsvararfordonsmodellen, beräkningar av totala energiförluster och flöden samt presentationav dessa i ett sankey diagram. Den andra delen innefattar optimering avenergihanteringssystems kontrollparametrar enligt olika representativa körcykler.Den tredje delen involverar utveckling av anpassningsbara energihanteringssystemgenom användning av optimala kontrollparameterar baserad på detektering avkörbeteende med hjälp av SVM ( stödvektormaskin).Slutligen, ett strukturerat sätt att generera sankey diagrammet har med framgånggenererats och visat sig vara ett effektivt verktyg för studier av HEV drivlinorseffektivitet och bränsleekonomi. Dessutom visar kombinationen av detektering avkörbeteende och optimerade kontrollparametrar på en markant potentiell förbättringi bränsleförbrukning.

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36

Xie, Kebin. "Dimensioning of a cutter wheel bearings." Thesis, Karlstads universitet, Institutionen för ingenjörsvetenskap och fysik (from 2013), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-80154.

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Mobile Miner 40V is a machine used for rock excavation and developed by Epiroc. This machine is equipped with a large cutter wheel to perform the excavation. After a test run, some surfaces associated with bearings within the cutter wheel were found to be damaged due to scuffing - severe sliding wear. There is a static load applied to the surfaces due to gravity. However, the reason for this damaged issue was believed that there is a large dynamic load applied to the surfaces during the excavation. This dynamic load was not found in a previous FE model used to verify safety issues. Therefore, a new FE model that is more in line with reality, and a failure analysis were required. Additionally, a feasibility study for a cutter wheel with a larger dimension was also needed since a larger cutter wheel is desirable. Firstly, wear mechanisms were reviewed, and some theories were chosen to analyze the damaged issue. Since it was unknown whether the surfaces were well-lubricated or not, both cases were investigated. The Archard wear equation was used to analyze the poor-lubricated situation, while the lubrication number and the Reynolds equation were used to analyze the well-lubricated case. Secondly, contact mechanisms between the surfaces were also investigated. The investigation of the contact mechanisms involved several theories, such as the Hertzian contact theory and the impact load factor. Besides these theoretical analyses, a numerical analysis was performed. Lastly, a new FE model was established in Ansys. Both the cutter wheel which was subjected to scuffing(existing cutter wheel), and the cutter wheel with a larger dimension(larger cutter wheel) were analyzed by the use of the new FE model. The maximum and minimum wear rates obtained by the Archard wear equation are approximately 1.9・10-2mm3/m and 4.8・10-3mm3/m, which are considered as a completely unacceptable level in engineering applications. The maximum and minimum critical loads obtained by the Reynold equation are approximately 1.8kN and 24.8kN, which both are larger than the static load applied to the surfaces. The maximum and minimum critical mean contact pressures obtained by the lubrication number are approximately 65MPa and 240MPa, which both are larger than the mean contact pressure generated by the static load. No evidence shows that there is a large dynamic load applied to the surfaces during the excavation. The largest possible contact pressure on the bearings in the existing cutter wheel is very close to the limit of severely damaged. The largest possible contact pressure on the bearings in the larger cutter wheel is believed to exceed the limit of severely damaged. The previous assumption that the surfaces were damaged due to a large dynamic load was wrong. The obtained results support that the surfaces were only subjected to a static load and were damaged due to inadequate lubrication. The existing cutter wheel is operated safely with the current load cases. However, the forward thrust force is suggested to decrease when the cutting angle is large. There is a high risk if the larger cutter wheel is operated with the current load cases.

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Hägglund, Jonathan, and Oscar Möller. "Conceptual Designs of Weight Optimized Wheel." Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-34287.

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Escenda Engineering AB is a Gothenburg located engineering consultancy company. They mainly work towards the automotive industry and are a supplier for Polestar Performance AB, which develops high-performance Volvo cars. This thesis is based on an older Bachelor Thesis where a topology optimized, or weight-optimized, wheel was developed for Polestar Performance’s Volvo S60 and V60. The main goal with this thesis is to further develop the obtained results from this wheel. The work-methods that has been chosen for this thesis is the early parts of Fredy Olsson and parts of the design method that is presented by SVID (Stiftelsen Svensk Industridesign, The foundation of Swedish industry design). In this thesis, great importance has been given to research regarding the different manufacturing methods on which the authors believe could be relevant if a wheel of this kind would be manufactured. The thesis will also give an account for various conceptual designs followed by a final conceptual design and end with a critical review regarding the whole project.

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Galas, Radovan. "Friction Modification within Wheel-Rail Contact." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-367508.

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Předložená disertační práce se zabývá experimentálním studiem modifikátorů tření a maziv pro temeno kolejnice, které jsou aplikovány do kontaktu kola a kolejnice za účelem optimalizace adheze a redukce hluku. Hlavním cílem práce bylo objasnit vliv aplikovaného množství a složení těchto látek na adhezi v kontaktu. Hlavní pozornost byla věnována zejména potencionálním hrozbám souvisejících s kriticky nízkou adhezí, která může nastat po aplikaci těchto látek. Experimentální studium probíhalo v laboratorních i reálných podmínkách, konkrétně v tramvajovém provozu. V případě laboratorních experimentů byl využit komerční tribometr a dvoudiskové zařízení umožňující simulovat průjezd vozidla traťovým obloukem. Kromě samotné adheze bylo při experimentech sledováno také opotřebení a míra hluku. Výsledky ukázaly, že maziva pro temeno kolejnice jsou schopna poskytovat požadované třecí vlastnosti, nicméně jejich chování je silně závislé na aplikovaném množství. V případě předávkování kontaktu dochází ke kriticky nízkým hodnotám adheze, které vedou k výraznému prodloužení brzdné dráhy. V případě modifikátorů tření bylo ukázáno, že chování těchto látek je výrazně ovlivněno odpařováním základního média. Výsledky také ukázaly, že nadměrné množství částic pro modifikaci tření může způsobit kriticky nízké hodnoty adheze. U obou výše zmíněných typů produktů byl prokázán pozitivní vliv na míru opotřebení a míru poškození povrchu, zatímco významná redukce hluku byla dosažena pouze v případech, kdy došlo ke značnému poklesu adheze. V závěru této práce jsou uvedena doporučení pro další výzkumné aktivity v této oblasti.

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Inglot, Agnieszka, and Oskar Franzén. "PREVENTION OF WHEEL WEAR, A CASE STUDY : Developing a functioning wheel profile for rail-mounted transportation trolley." Thesis, Högskolan i Skövde, Institutionen för ingenjörsvetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-17695.

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This bachelor’s degree project aimed to improve the wheel profile of a rail mounted trolley and determine the cause of wheel failure. The proceedings of this project where modelled after an approach for solving wear problems with an emphasis on designing for sustainability. A case study and root cause analysis (RCA) was performed and the flanged wheels were deemed insufficient for the given heavy-haul system. Possible areas of wheel profile improvement were identified and further researched with multiple literature reviews. Throughout the projects duration several limitations were introduced that reduced the concept testing to exclusively theoretical prediction models. Archard’s model was implemented to predict wear and operating time for the proposed material and wheel tread profile concepts. The wheel flange dimensions were chosen based on recommendations from wheel and rail interference handbooks among other sources. The final wheel and rail profile suggestion improved operating time by approximately 300% and wear resistance by 50% compared to its predecessor. This result was achieved by applying the same theoretical prediction model to both current and suggested profiles. The findings of this project are meant to aid SCA among others in similar cases and additionally highlight the value of product improvement from a technological, sociological, and environmental perspective.

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Norin, Gustav. "Detecting External Forces on an Autonomous Lawnmowing Robot with Inertial, Wheel Speed and Wheel Motor Current Measurements." Thesis, Linköpings universitet, Reglerteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-137434.

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An autonomous lawn mowing robot moves around randomly within an area enclosed by a magnetic wire and makes decision based on sensor information. To ensure human and animal safety it is essential that the robotic lawn mower can detect and stop if, for instance, it is being lifted by a human. This thesis takes a look at how on-board sensors could be used to detect a few critical events, here called fault cases. Data such as acceleration, angular velocity and motor currents are recorded and then used to develop three methods for detection briefly de-scribed below. The Odometry method uses constraints on valid movement of the robotic lawnmower and a fault case is detected if estimated velocity in global coordinates violates these constraints. The pitch angle relationship estimates the relation between electrical currents needed to drive the robotic lawn mower at a certain speed in certain pitch angle. When the electrical currents corresponding to a certain pitch angle according to the relation deviates from measured currents a fault case would be detected. The frequency method is based on the idea that disturbances on signals caused by uneven ground should decrease when the robotic lawn mower is lifted or held. The method would then detect this damping of disturbances by examining frequency content. The best method is the pitch angle relationship while the other two proposed methods have potential but would need higher sampling frequencies and additional signals to fully perform satisfactorily. With additional information such as position of the robotic lawn mower the estimation of the global velocities could be significantly improved which in turn would improve the odometry method and serve as a complement to the current pitch angle relation. The frequency methods would also be valid if the sampling frequencies were much higher, some-thing that might not be as cost efficient as needed to make the method profitable.

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Flensén, Martin, and Lucht Kristian Benterås. "Prognostisering av utrustningar på Volvo Wheel Loaders." Thesis, Jönköping University, JTH, Industrial Engineering and Management, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-16.

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Volvo in Arvika produces wheel loaders, and the production is based on forecasts. When a machine is ordered, the customer can choose what type of equipment he or she wants, and these equipments are also made forecasts on. This is made by giving each equipment an estimated procentual usage that shows how many of the machines that will use this option. Today two people are working with the forecasts, planer A in Eskilstuna and planer B in Arvika. Planer A makes a forecast based on the historical outcome and planer B then makes adjustments of this based on how many options that are ordered. Volvo in Arvika is having problems with the accuracy of the forecasts and because of this they have got too much in stock. But how big are the forecast deviations, what is the cause of it, in what or which places does the process lack? What can be made to make more accurate forecasts, how can you get a more affective process with less work made? To answer these questions we surveyed the process and analyzed it to find strong and week spots. We found that Planer A has a lack of information about how the forecast influence the stock in Arvika, that she gets pour feedback from production, that Planer B is the only one with knowledge about the forecast work in Arvika. We also made a benchmarking with the factory in Braås to see how they differ. Just like in Arvika there are two people working with the forecasts, but in Braås both of them are located close to the production and they share the options equal. They are also able to fill in for each other if someone would be sick.

To see how much the forecast differ from market demand, we have analyzed forecast data from nine different options for eight months. It turned out that the automatic calculated forecasts are a bit high and that planner B lower them.

Our conclusion is that the forecasts should be made only in Arvika, and not as it is today when half of it is made in Eskilstuna. There should also be documents and routines on how the work shall be done. This is to make it easier for people that will do the same job in the future.

Volvo Wheel Loaders (WLO) i Arvika tillverkar hjullastare och gör detta mot prognos. Till hjullastarna finns olika utrustningar som kunden kan välja mellan och även dessa gör Volvo prognoser på. Detta görs genom att de uppskattar hur många procent av maskinerna som kommer använda varje utrustning och lägger in det i ett program. Idag arbetar två personer med prognoserna, planerare A på huvudkontoret i Eskilstuna och planerare B på plats i Arvika. Planerare A gör först prognosen med avseende på historiskt utfall, sedan justerar planerare B dessa gentemot bl.a. orderingång. WLO har problem med träffsäkerheten i sina utrustningsprognoser och detta har medfört höga lagernivåer och därmed bundet kapital. Hur stora är prognosavvikelserna, vad är det som gör att prognoserna blir fel, på vilket eller vilka ställen i processen är det som bristerna uppstår? Vad kan de göra för att få bättre prognoser, hur kan man effektivisera processen så att det blir mindre arbete? För att svara på dessa frågor började vi med att kartlägga prognostiseringsprocessen och sedan analysera den för att få fram svagheter och styrkor. Här fann vi t ex att planerare A inte har någon kunskap om hur prognoserna påverkar lagret i Arvika och att hon får för dålig feedback från produktion, att planerare B är ensam kunnig om prognosarbetet vilket leder till problem när han är sjuk eller borta av andra skäl.

Sedan gjorde vi även en processjämförelse med Volvo Braås för att se hur de skiljer sig åt. I Braås är det två personer som tar fram prognoserna och de arbetar med hälften av utrustningsnumren var. Båda sitter nära produktion och är även väl insatta i varandras arbete om någon av dem skulle vara borta.

För att få fram hur prognoserna avviker från utfallet har vi gått igenom prognoshistorik för nio olika typer av utrustningar och sedan gjort beräkningar på det materialet. Det visade sig att prognoserna som automatiskt beräknas ofta ligger för högt och att planerare B sänker dessa.

Vi har kommit fram till att allt arbetet med prognoserna borde ske på plats i Arvika och inte som i nuläget när hälften görs i Eskilstuna. Man bör även införa rutiner på hur arbetet med prognoserna ska gå till och göra dokument på detta så att det är lättare för personer som ska ta över eller måste sätta sig in hur det fungerar.

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Klomp, Matthijs. "Passenger car all-wheel drive systems analysis." Thesis, University West, Department of Technology, Mathematics and Computer Science, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-742.

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Karlsson, Johan, and Maria Nordin. "Energieffektivisering på GETRAG All Wheel Drive AB." Thesis, Linköping University, Department of Management and Engineering, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-8324.

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En ökad kostnadseffektivitet i svenska företag är viktigt för att dessa ska kunna bibehålla sin internationella konkurrenskraft. Då el- och andra energipriser förutsägs stiga i framtiden ökar även företagens energikostnader. Genom energieffektivisering kan företag minska sina kostnader utan att förlora konkurrenskraft.

Detta arbete har utförts på GETRAG All Wheel Drive AB i Köping och syftar till att kartlägga företagets energianvändning och därigenom lokalisera potentiella möjligheter till energieffektivisering av företagets olika processer. Kartläggningen har haft särskilt fokus på elenergianvändningen då denna står för den största kostnaden bland energislagen. Hänsyn har endast tagits till möjliga besparingar och ingen investeringskostnad för effektiviseringsåtgärderna har beräknats.

Kartläggningen har genomförts genom mätningar av elanvändningen på produktionsnivå i kronhjulstillverkningen samt insamling av övergripande mätdata över elanvändningen för övriga stöd- och produktionsprocesser. Dessa mätvärden användes för att identifiera de processer som har störst möjlighet till energieffektivisering.

Resultatet visar på att stora möjligheter till effektiviseringsåtgärder finns på GETRAG. Åtgärdsförslagen delas in i tre alternativ utifrån hur stora investeringar som uppskattningsvis krävs. De åtgärder som föreslås är minskad belysning, minskad tomgång, minskad ventilation, konvertering av icke elspecifika processer till uppvärmning med fjärrvärme samt laststyrning.

För Alternativ 1 som endast kräver ett fåtal små investeringar finns en besparingspotential på ungefär 1,8 Mkr vilket motsvarar en minskning av elanvändningen med 7 %. Följande Alternativ 2 ger en besparing på 4,4 Mkr och minskar elanvändningen med 21 % men kräver dock något större investeringar. Slutligen ger Alternativ 3 genom relativt stora investeringar en besparingspotential på 5,8 Mkr samt en minskad elanvändning med 25 %.

Increased cost efficiency is of great importance for Swedish companies to maintain their ability to compete on an international market. Electricity as well as other energy prices are predicted to rise rapidly during forthcoming years leading to increasing energy costs. Through energy efficiency measures companies are able to reduce their costs while maintaining their competitiveness.

This study is a masters thesis performed for GETRAG All Wheel Drive AB in Köping at the Institute of Technology in Linköping. The purpose of the thesis is to make a survey of the energy usage in the plant and by doing so locating potential possibilities to energy efficiency measures. The survey is mainly focusing on electricity usage due to electricity being the major energy cost. Consideration has only been taken to possible energy savings and no investment costs have been calculated.

The survey has been carried out through a number of measurements of the electricity usage in machines used in the manufacturing of crown wheels. A comprehensive data collection has also been made, presenting the energy usage of the support and the production processes. The data was used to identify processes with the largest possibilities of energy efficiency measures.

The conclusion of the survey is that there are great opportunities for energy efficiency measures at GETRAG AWD AB. The measures have been divided into three different categories on the basis of estimated investment costs. The suggested measures are reduced lighting, reduced idling losses, reduced ventilation, load control and conversion for non electricity specific processes into heating by district heating.

In Alternative 1 where only a few minor investments are needed a potential saving of approximately 1.8 million SEK is calculated. This corresponds to an electricity usage reduction by 7 %. The following, Alternative 2, generates a saving of 4.4 million SEK and the electricity usage is reduced by 21 %. Finally, Alternative 3, results in a saving of 5.8 million SEK and a decreased electricity usage by 25 %.

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Hag, Johan. "Wheel Corner Modules : Technology and Concept Analysis." Thesis, KTH, Farkost och flyg, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-89892.

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The wheel corner module represents a new technology for controlling the motion of avehicle. It is based on a modular design around the geometric boundaries of a conventionalwheel. The typical WCM consists of a wheel containing an electrical in-wheel propulsion motor, a friction brake, a steering system and a suspension system. Generally, the braking,steering and suspension systems are controlled by means of electrical actuators. The WCMis designed to easily, by means of bolted connections and a power connector, attach toa vehicle platform constructed for the specic purpose. All functions are controlled viaan electrical system, connecting the steering column to the module. A WCM vehicle cancontain two or four wheel corner modules.The purpose of this thesis is to serve as an introduction to wheel corner module technology.The technology itself, as well as advantages and disadvantages related to wheelcorner modules are discussed. An analysis of a variety of wheel corner module concepts iscarried out. In addition, simulations are conducted in order to estimate how an increasedunsprung mass aects the ride comfort and handling performance of a vehicle.Longitudinal translation over two types of road disturbance proles, a curb and a bump,is simulated. A quarter car model as well as a full car model is utilized. The obtainedresults indicate that handling performance is deteriorated in connection to an increase dunsprung mass. The RMS value of the tire force uctuation increases with up to 18%,when 20 kg is added to each of the rear wheels of the full car model. Ride comfort is deteriorated or enhanced in connection to an increased unsprung mass, depending on the disturbance frequency of the road. When subjected to a road disturbance frequency below the eigenfrequency of the unsprung mass, ride comfort deterioration is indicated. The RMS vertical acceleration of the sprung mass increases with up to 6%, in terms of the full car model. When subjected to a road disturbance frequency above the eigenfrequency ofthe unsprung mass, decreased RMS vertical acceleration of up to 25% is noted, indicatinga signicantly enhanced ride comfort. Implementation of wheel corner module technology enables improved handling performance,safety and ride comfort compared to conventional vehicle technology. Further development, e.g. in terms of in-wheel motors and alternative power sources, is however required. In addition, major investments related to manufacturing equipment andtechnology is regarded as a signicant obstacle in terms of serial production.

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Bihagen, Jennifer, and David Johnsson. "Productivity in construction production for wheel excavators." Thesis, Linköpings universitet, Kommunikations- och transportsystem, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-142878.

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Byggbranschen har en låg produktivitetsutveckling i jämförelse med andra industribranscher. Den låga produktivitetsnivån medför stora kostnader för byggföretagen. För att vända trenden krävs det en kartläggning av nuvarande produktivitet för att sedan kunna genomföra en förändring. Ett nytt verktyg för att mäta produktivitet för maskiner ska införas hos Skanska AB och i denna studie utförs mätningen på grävmaskiner på hjul i ett vägprojekt. Mätningen går till så att en produktivitetsmätare placeras på en grävmaskin. Mätaren registrerar rörelse och skickar data till en server som sedan gör om indata till rapporter. Studien har tre syften: det första är att kartlägga normalläget av rörelse för grävmaskiner på hjul, det andra är att ta reda på varför grävmaskinerna inte utnyttjas till högre grad och det sista är hur produktivitetsmätning av grävmaskiner kan minska graden av stillastående inom byggproduktion. De metoder som använts är objektiv mätning, intervjuer och dagböcker. Normalläget av rörelse identifieras till 7273% för grävmaskinerna i projektet som studien utförts vid. Detta är alltså ett stillestånd på 2728%. Målet är 0% stillestånd men ett riktvärde att uppnå är 2025%. Det finns olika typer av stillestånd, de som är planerade och de som är oplanerade. Det som är mest intressant i denna studie är de oplanerade. De vanligaste orsakerna till oplanerade stillestånd uppges vara brister i planeringen, oväntade fel såsom maskinhaveri och sjukdom. Anledningar till planerade stillestånd är ledighet, möten och raster. För att förbättra produktiviteten, minska slöseri och stillestånd av arbetstid för grävmaskiner kan de värden som fås från produktivitetsmätarna användas som en punkt i veckomöten där orsaker bakom data diskuteras. Det blir då en naturlig del av mötet att prata om produktiviteten.

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PRASANTH, NANDANAVANAM MANO. "Hauler Detection for an Autonomous Wheel Loader." Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-26405.

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In this thesis work, we evaluate an object recognition system for an autonomous wheel loader, to detect objects in its vicinity, in particular an articulated hauler truck, by using an interest point extraction method that explicitly considers object borders information, combined with a feature descriptor known as Normal Aligned Radial Features (NARF) in 3D point cloud data. The object recognition technique relies on extraction of NARF from range images (computed from point clouds) for both model(hauler) and the scene. The technique used is robust feature matching where the extracted model features are mapped on to the scene containing the model and then seeking for a best transformation that aligns the model with respect to the scene. In this context we conducted several experiments with many number of 3D scans obtained from the laser scanner mounted on the top of an autonomous wheel loader to analyze the accuracy of the object recognition system. Finally we demonstrated the results, as the system is able to recognize the hauler from any view point. vii

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Müller, Steffen. "Linearized wheel-rail dynamics : stability and corrugation /." Düsseldorf : VDI-Verl, 1998. http://www.gbv.de/dms/bs/toc/265578795.pdf.

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Nilsson, Tomas. "Optimal Predictive Control of Wheel Loader Transmissions." Doctoral thesis, Linköpings universitet, Fordonssystem, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-112722.

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The transmissions of present heavy wheel loaders are in general based on torque converters. The characteristics of this component suits these machines, especially in that it enables thrust from zero vehicle speed without risk of stalling the engine, without active control. Unfortunately, the component also causes losses which might become large compared to the transmitted power. One approach for mitigating these losses is to switch to a continuously variable transmission. Changing to such a system greatly increases the possibility, and the need, for actively selecting the engine speed, and here a conflict emerges. A low engine speed is desired for high efficiency but a high speed is required for high power. Heavy wheel loaders often operate according to a common repeating pattern known as the short loading cycle. This cycle is extremely transient, which makes the choice of engine operating point both important and difficult. At the same time, the repeating pattern in the operation enables a rough prediction of the future operation. One way to use the uncertain prediction is to use optimization techniques for selecting the best control actions. This requires a method for detecting the operational pattern and producing a prediction from this, to formulate a manageable optimization problem, and for solving this, and finally to actually control the machine according to the optimization results. This problem is treated in the four papers that are included in this dissertation. The first paper describes a method for automatically detecting when the machine is operating according to any of several predefined patterns. The detector uses events and automata descriptions of the cycles, which makes the method simple yet powerful. In the evaluations over 90% of the actual cycles are detected and correctly identified. The detector also enables a quick analysis of large datasets. In several of the following papers this is used to condense measured data sequences into statistical cycles for the control optimization. In the second paper dynamic programming and Pontryagin’s maximum principle is applied to a simplified system consisting of a diesel engine and a generator. Methods are developed based on the maximum principle analysis, for finding the fuel optimal trajectories at output power steps, and the simplicity of the system enables a deeper analysis of these solutions. The methods are used to examine and visualize the mechanisms behind the solutions at power transients, and the models form the basis for the models in the following papers. The third paper describes two different concepts for implementing dynamic programming based optimal control of a hydrostatic transmission. In this system one load component forms a stochastic state constraint, and the concepts present two different strategies for handling this constraint. The controller concepts are evaluated through simulations, in terms of implementability, robustness against uncertainties in the prediction and fuel savings. The fourth paper describes the implementation and testing of a predictive controller, based on stochastic dynamic programming, for the engine and generator in a diesel electric powertrain. The controller is evaluated through both simulations and field tests, with several drivers, at a realistic work site, thus including all relevant disturbances and uncertainties. The evaluations indicate a ∼ 5% fuel benefit of utilizing a cycle prediction in the controller.

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Smith, Lindsey. "Rolling contact fatigue in wheel-rail contact." Thesis, University of Newcastle Upon Tyne, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.438385.

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Abdul-Wahab, Fazlil-Ilahi bin. "The tractive performance of cage wheel lugs." Thesis, University of Newcastle Upon Tyne, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315586.

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Dissertations / Theses on the topic 'Wheel'

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