Motorsport has become a multidisciplinary sport in which skilled engineers and strategists play as big a part in the team’s success as the athlete driving the car. In Formula One it is common practice for teams to have dedicated resources on the track that are supported by a second team back at the home base who analyses telemetry data and performs simulations to refine the racing strategy. Optimal control calculations are typically used to optimise vehicle setup parameters (such as ride height and heave spring stiffness) and driver inputs (such as braking and steering) specific to each track. Traditionally this approach has been employed by minimising time over a single lap. Although this is useful in qualifying simulations, there is an unexplored element of optimising a vehicle’s "race pace". Drivers complete qualifying laps using minimal fuel with new tyres to get the best possible lap time but this performance cannot be sustained throughout the whole race. Drivers need to manage their tyres so that they do not wear prematurely and have a detrimental effect on their performance. This work places an emphasis on tyre modelling and in particular how optimal control can be used to optimise a tyre management strategy. A model has been presented that reduces grip as a function of tyre wear. This ensures that the qualifying pace cannot be sustained indefinitely. A thermodynamic model consisting of two states (surface and carcass temperature) is used to calculate tyre wear, which ultimately dictates how much grip can be provided by each tyre. The objective function for the optimal control problem is to minimise time over multiple laps and the absolute tyre wear (in mm tread) is constrained to a predefined limit. This ensures that the consequences of pushing the car to its limits are considered: overheating temperatures and accelerated wear will be detrimental to racing performance. The optimal control solver needs to manage the tyre temperatures carefully over a racing distance. It has been shown that lap times degrade more severely as the tyres reach the end of their life. At some point in the race this drop off in performance will render the car uncompetitive and strategists can use this model to evaluate the performance of different tyre compounds at each track and to strategically plan pit stops during a race. / Dissertation (MEng (Electronic Engineering))--University of Pretoria, 2020. / Electrical, Electronic and Computer Engineering / MEng (Electronic Engineering) / Unrestricted

The accumulation of microplastics (MPs) are a growing concern for the environment, the maximum contributor to the MP pollution is tyre wear particles or TWPs. TWPs can accumulate in the environment and remain there for long periods of time and hence have the ability to disrupt ecosystems. With nearly 6,000,000 tons of TWPs being emitted each year globally there is a need to study theiroccurrence and fate in terms of why and how these particles get created and where they end up in the environment. The occurrence and fate of tyre wear particles (TWPs) were investigated, and a model was created in Python to simulate the flow of TWPs in a stormwater system at a test site on Highway E18 in Sweden. In the literature review it was found that the generation of TWPs is highly dependent on annual average daily traffic and the type of the road; it is also dependent on the driving behaviour such as acceleration, making unnecessary turns and the use of studded tyres in the winter. The TWPs are generally transported via stormwater but wind also plays a crucial role in transporting TWPs which are of a smaller size than 10 µm. Although the common notion is that the TWPs get washed into rivers,the literature review also suggests that most TWPs get trapped in soil that is covered with vegetation. Three processes were simulated in the developed model, namely transport, hetero-aggregation and settling. The results clearly show that a rainfall with an intensity of 40 mm during 15 min providesminimum settling in the stormwater system, and a 10 mm rainfall with a duration of more than 30 hasmaximum settling. Hetero-aggregation and settling is directly dependent on particle size and hence larger particle sizes have a higher probability of attaching to another particle or to settle in the pipes or wells of the stormwater system. It was also observed that the flow patterns such as depth, discharge and velocity of flow largely affect the settling and hetero-aggregation in the stormwater system. Most particles remain unaffected in short duration and high intensity rainfalls; the opposite is true for the longer duration and lower intensity rainfalls. Using the model, a stormwater system can be designed to trap or to flush out TWPs from the system. Also, the concentration of TWPs in the sinks can be known using the model that is created in this study

The tyre is an essential part of a road vehicle. It is in the contact between road and tyre that the forces that create the possibility for the driver to control the vehicle are generated. Tyres, however, wear down, which leads to both unhealthy wear particles and disposal of old tyres, both of which are harmful to the environment. If one could learn more about what causes wear, it might be possible to reduce tyre wear, which would be beneficial from both an economic and an ecological point of view. The aim of this thesis work is to develop a tyre model that can simulate tyre wear and take temperature, pressure and vehicle settings into account. Based on tyre brush theory, a tyre wear model has been developed which includes a thermal model, a pressure model and a friction model. Simulations and analysis of different cases has been performed. From the results, one can conclude the following: the tyre temperature and inflation pressure change with the distance the vehicle travels at the beginning and later become steady; higher external temperature will decrease tyre wear rate since the inflation pressure increases with the external temperature and the sliding friction decreases; higher vehicle speed leads to a higher tyre wear rate; the tyre temperature increases with increasing vehicle speed; the amount of tyre wear increases linearly with the normal load on the tyre; the tyre wear increases with the slip ratio exponentially due to both the siding distance and the sliding friction increasing with the slip ratio; the tyre wear increases exponentially with the slip angle. The complete model can estimate the tyre wear with different vehicle settings and external factors. More experiments are needed in the future to validate the complete model. In addition, since the heat transfer coefficient is changeable with temperature, the thermal model can be improved by introducing dynamic heat transfer coefficients. The Savkoor friction model used in the report can also be improved by tuning its parameters using more experimental data.

The main current challenges of the mining industry include aspects such leveraging the mine productivity, controlling costs and reducing environmental impacts. In most surface mining operations, overburden removal requires haulage over short distances. A comparison of different haulage options for short distances with respect to energy efficiency in open-pit mining is a key aspect for decision making, but only a limited number of recent research efforts have considered energy efficiency as a control variable in mining projects. Loading and haulage have an energy source that is highly dependent on fossil fuels. In addition, the equipment involved in these operations use tyres as an important input. There are many studies relating the fuel consumption and tyre wear to several performance indicators, but a methodology that identifies and prioritizes higher-impact variables under each specific operating condition is not available. This research proposes new methods using alternative equipment simulations for fuel consumption and tyre wear management. Such methods include multiple regression analysis, stochastic simulation and specialized software routines in order to identify and control operational performance variables related to diesel consumption, tyre wear and selection of new alternatives equipments. Considering alternative scenarios of equipment models, the results of the proposed method include a 14% reduction in specific fuel consumption and a 16% increase in productivity. Regarding the fuel management method, the reduction of diesel consumption reached 10%. For the tyre wear management method, the results indicated a potential to save up to 8.9 t of tyre rubber in only one quarter. / Na atualidade, a indústria de mineração possui como principal desafio alavancar sua produtividade, controlar custos e reduzir impactos ambientais. Muitas operações de mineração exigem transporte em pequenas distâncias. A comparação de diferentes opções de transporte em distâncias curtas considerando a eficiência energética é uma necessidade de operações de lavra a céu aberto, mas existem poucos estudos recentes que priorizam esta variável em projetos de mineração. As operações de carga e transporte são amplamente dependentes de combustíveis fósseis. Essas operações também necessitam de pneus como um importante insumo. Existem alguns trabalhos que relacionam o consumo de combustíveis e o desgaste dos pneus a variáveis operacionais, mas uma metodologia que identifique as variáveis de maior impacto frente a condições específicas ainda não está disponível. O presente trabalho fornece novos métodos de simulação para equipamentos alternativos, consumo de combustíveis e gestão do desgaste de pneus. Análises de regressão linear múltipla, simulações e ferramentas de desenho de mina permitem identificar e controlar variáveis ligadas ao consumo de combustíveis, desgaste de pneus e seleção de equipamentos. Os estudos envolvendo equipamentos alternativos alcançaram uma redução de 14% no consumo de diesel e um aumento de 16% na produtividade. Com relação às técnicas de gestão do consumo de combustível aplicada aos caminhões observou-se uma redução de 10%. Considerando o sistema de gestão de desgaste de pneus, a aplicação do método proposto possui um potencial de evitar o descarte de 8,9 t de borracha para pneus em apenas um trimestre.

The main current challenges of the mining industry include aspects such leveraging the mine productivity, controlling costs and reducing environmental impacts. In most surface mining operations, overburden removal requires haulage over short distances. A comparison of different haulage options for short distances with respect to energy efficiency in open-pit mining is a key aspect for decision making, but only a limited number of recent research efforts have considered energy efficiency as a control variable in mining projects. Loading and haulage have an energy source that is highly dependent on fossil fuels. In addition, the equipment involved in these operations use tyres as an important input. There are many studies relating the fuel consumption and tyre wear to several performance indicators, but a methodology that identifies and prioritizes higher-impact variables under each specific operating condition is not available. This research proposes new methods using alternative equipment simulations for fuel consumption and tyre wear management. Such methods include multiple regression analysis, stochastic simulation and specialized software routines in order to identify and control operational performance variables related to diesel consumption, tyre wear and selection of new alternatives equipments. Considering alternative scenarios of equipment models, the results of the proposed method include a 14% reduction in specific fuel consumption and a 16% increase in productivity. Regarding the fuel management method, the reduction of diesel consumption reached 10%. For the tyre wear management method, the results indicated a potential to save up to 8.9 t of tyre rubber in only one quarter. / Na atualidade, a indústria de mineração possui como principal desafio alavancar sua produtividade, controlar custos e reduzir impactos ambientais. Muitas operações de mineração exigem transporte em pequenas distâncias. A comparação de diferentes opções de transporte em distâncias curtas considerando a eficiência energética é uma necessidade de operações de lavra a céu aberto, mas existem poucos estudos recentes que priorizam esta variável em projetos de mineração. As operações de carga e transporte são amplamente dependentes de combustíveis fósseis. Essas operações também necessitam de pneus como um importante insumo. Existem alguns trabalhos que relacionam o consumo de combustíveis e o desgaste dos pneus a variáveis operacionais, mas uma metodologia que identifique as variáveis de maior impacto frente a condições específicas ainda não está disponível. O presente trabalho fornece novos métodos de simulação para equipamentos alternativos, consumo de combustíveis e gestão do desgaste de pneus. Análises de regressão linear múltipla, simulações e ferramentas de desenho de mina permitem identificar e controlar variáveis ligadas ao consumo de combustíveis, desgaste de pneus e seleção de equipamentos. Os estudos envolvendo equipamentos alternativos alcançaram uma redução de 14% no consumo de diesel e um aumento de 16% na produtividade. Com relação às técnicas de gestão do consumo de combustível aplicada aos caminhões observou-se uma redução de 10%. Considerando o sistema de gestão de desgaste de pneus, a aplicação do método proposto possui um potencial de evitar o descarte de 8,9 t de borracha para pneus em apenas um trimestre.

Driving with tyres not appropriate for the actual conditions can not only lead to accidents related to the tyres, but also cause detrimental effects on the environment via emission of rubber particles if the driving conditions are causing an unexpectedly high amount of tread wear. Estimating tyre performance in an online setting is therefore of interest, and the feasibility to estimate friction performance, velocity performance, and tread wear utilizing available information from the automotive grade sensors is investigated in this thesis. For the friction performance, a trend analysis is performed to investigate the correlation between tyre stiffness and friction potential. Given that there is a correlation, a model is derived based on the trend having a stiffness parameter as an input in order to predict the friction performance. Tendencies for a linear trend is shown, and a linear regression model is fitted to data and is evaluated by calculating a model fit and studying the residuals. Having a model fit of $80\%$, the precision of the expected values stemming from the proposed model is concluded to be fairly low, but still enough to roughly indicate the friction performance in winter conditions. A tread wear model that can estimate the amount of abrasive wear is also derived, and the proposed model only utilizes available information from the automotive grade sensors. Due to the model having a parameter that is assumed to be highly tyre specific, only a relative wear difference can be calculated. The model is evaluated in a simulation environment by its ability to indicate if a tyre is under the influence of a higher wear caused by a higher ambient temperature. The results indicates that the model is insufficient in an online setting and cannot accurately describe the phenomena of softer tyres having a larger amount of wear caused by a high ambient temperature compared to stiffer tyres. Lastly, a double lane change test (ISO 3888-2) is conducted to determine the critical velocity for cornering manoeuvres, which defines the velocity performance. The test was executed for six different sets of tyres, two of each type (winter, all-season, and summer). The approach to estimate the velocity performance in an online setting is analogue to that of the friction performance, and a trend analysis is performed to investigate the correlation between longitudinal tyre stiffness and the critical velocity. The results are rather unexpected and shows no substantial differences in velocity performance, even though the tyre-road grip felt distinctively worse for the softer tyres according to the driver. It is concluded that the bias stemming from the professional driver's skills might have distorted the results, and that another approach might need to be considered in order to estimate this performance.

Tyre wear is a vital problem in vehicles, especially in articulated vehicles because of their heavier axle loads. Tyre wear can not only do harm to vehicle dynamics but also cause tyre particle emissions. Therefore, solutions that can minimise tyre wear are where this thesis work focuses. The suspension design is one of the main factors affecting tyre wear. This thesis considers different kinds of semi-active (such as ADD, SH-2 and GH-2) and active suspensions (\(H_\infty\) control) and compares them with a passive suspension with regards to tyre wear. Driving comfort and road holding are considered as well. The simulation starts by running a IPG/TruckMaker model on a route introducing a certain road roughness profile, and outputs lateral slip angles, which together with vehicle parameters and route data are input into a Simulink model. Then, based on the static vertical load on each axles of the articulated vehicle, three different quarter car models corresponding to the axles with various suspension systems are built in Simulink. Simulation results show that the active suspension (\(H_\infty\) control approach) works best in minimising tyre wear, reducing tyre wear by 1-10\% compared to the passive suspension when the vehicle is driving on road profile Class C (country road). Meanwhile, several control strategies of \(H_\infty\) control are applied in order to result in overall good vehicle performance considering comfort and road holding. Semi-active suspensions also work well in reducing tyre wear, but the amount of tyre wear reduction is lower than that of the \(H_\infty\) controllers. / Däckslitage är ett viktigt problem för fordon, särskilt för tunga ledade fordon på grund av deras högre axellaster. Däckets slitage påverkar inte bara fordonets dynamik utan orsakar också utsläpp av däckpartiklar. Olika lösningar behöver utvecklas som kan minimera däckslitage och det är fokus för detta examensarbete. Hjulupphängningens konstruktion är en viktig faktor som påverkar däckslitaget. Detta arbete studerar olika typer av semiaktiva (såsom ADD, SH-2 och GH-2) och aktiva fjädringssystem (\(H_\infty\) reglering) och jämför dem med ett passivt fjädringssystem när det gäller däckslitage, samtidigt som även körkomfort och väghållning beaktas. Simuleringarna inleds med att en IPG/TruckMaker fordonsmodell kör längs en sträcka med en viss typ av vägojämnhet. Simuleringarna resulterar i avdriftsvinklar för fordonet som tillsammans med fordonsparametrar och ruttinformation skapar indata till en Simulink-modell. Därefter, baserat på den statiska vertikala belastningen på varje axel i det ledade fordonet, skapas tre olika kvartsbilsmodeller i Simulink som motsvarar axlarna med deras olika hjulupphängningssystem.Simuleringsresultaten visar att den aktiva fjädringen (\(H_\infty\)) fungerar bäst när det gäller att minimera däckslitage, där slitaget minskar med 1-10\% jämfört med den passiva fjädringen när fordonet kör på vägprofil klass C (landsväg). Samtidigt tillämpas flera olika \(H_\infty\) reglerstrategier för att åstadkomma överlag goda fordonsprestanda även med avseende på komfort och väghållning. Semiaktiva fjädringssystem fungerar också bra för att minska däckslitaget, men minskningen av slitaget är lägre än den för den aktiva \(H_\infty\) fjädringen.

Tyre wear is a significant problem on today's road vehicles, particularly for heavy trucks. As the tyre wears, microplastics is released in the air causing long term health issues and environmental pollution. With the introduction of automated vehicles there is a big potential to improve tyre wear of heavy trucks. In this direction, this thesis investigates the fundamentals of motion planning for minimising the lateral tyre wear in cornering for automated articulated vehicles. The trade-off between journey time and tyre wear is analysed. For the simulations, firstly an articulated vehicle model is used from the literature and validated with IPG/TruckMaker. Secondly, a sensitivity analysis is conducted on the articulated vehicle on a couple of parameters. The front cornering stiffness, hitch point, trailer mass and trailer centre of gravity position where the parameters influence on tyre wear is analysed. The results showed that moving the hitch point forward decreases the total tyre wear, increasing mass of the trailer increases tyre wear while the front cornering stiffness and centre of gravity position of the trailer did low to no difference to the total tyre wear. Then, an optimal control problem was configured to investigate the motion planning of an articulated vehicle. Then, the motion planning system is configured to find an optimal feasible trajectory with respect to dynamic and path constraints for the articulated vehicle to minimise lateral wear at a predefined path for fixed journey times. Four case different configurations of the problem are investigated to study the influence of driving style, lateral manoeuvrability allowance, vehicle acceleration capabilities and of the number of steering axles on the tractor. The results showed that motion planning can be used for minimising lateral tyre wear. The case study with largest impact on tyre wear was driving style, where the tyre wear showed significant difference between slow driving and aggressive driving. The second case study showed that wider lateral allowance led to less tyre wear and increasing the acceleration capabilities also decreases lateral tyre wear. The additional steering axle on the truck decreased tyre wear at higher velocities but for lower velocities the difference was negligible. / Däckslitage är ett signifikant problem både ur ett miljöperspektiv och ur ett ekonomiskt perspektiv. Väldigt lite fokus läggs på utsläpp från däck när olika utsläppskällor diskuteras. När transportsamhället rör sig mot automation finns det stora möjligheter att utnyttja automatiserade fordon för att minska däckslitage. Det här examensarbetet undersöker möjligheterna att minimera däckslitage genom ruttplanering för automatiserade lastbilar med en artikulationspunkt. Ett optimeringsproblem formuleras och definieras med två målfunktioner för att undersöka hur det laterala däckslitaget i kurvor kan minimeras utan att förlänga restiden. Ruttplaneringens uppgift är att finna den mest optimala rutten med hänsyn till den fördefinierade vägen, fordonets dynamiska begränsningar och vägens begränsningar. Fyra delstudier genomförs, där körstil, vägbredd, maximal tillåten acceleration och påverkan av en ytterligare styrande axel undersökes. För att genomföra simuleringarna implementeras en bilmodell från litteraturen. Bilmodellen jämförs sedan med ett program för att validera dess noggrannhet och robusthet. Sedan görs en känslighetsanalys med hänsyn till däckslitage på några fordonsparametrar, nämligen artikuleringspunkten, framaxelns kurvstyvhet, placering av släpets tyngdpunkt och släpets vikt. Resultatet påvisade att ruttplanering är en bra metod för att minimera däckslitage, resultatet visade att körstil var en viktig faktor till däckslitage, där aggressiv körstil resulterade i mer slitage. Sedan visades det att vägbredd också hade en stor påverkan, där bredare vägar gav upphov till mindre slitage, och smalare vägar gav upphov till mer slitage. Vid högre tillåtna acclerationsnivåer blev däckslitaget lägre men högre vid lägre accelerationsgränser. När två styrbara axlar styrbara används så påvisades mindre däckslitage mot samma restid som när en axel är styrbar. Sist så visade känslighetsanalysen en stor skillnad på totalt däckslitage i relation till placering av artikuleringspunkten. Högre släpvikt gav också mer slitage medan placering av släpets tyngdpunkt och framaxelns kurvstyvhet gav upphov till låg ändring i totalt däckslitage.