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The Global ETD Search service is a free service for researchers
to find electronic theses and dissertations. This service is
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Networked Digital Library of Theses and Dissertations.
Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
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Showing 1 to 5 of 5 (0.016 seconds)Spelling suggestions: "subject:"anytime"" "subject:"andtime""
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A study of a robust and accurate framework for Minimum-time optimal control of high-performance cars: from coaching professional drivers to autonomous racing.Pagot, Edoardo 27 January 2023 (has links)
In motorsport, simulating road vehicles driving at the limit of handling is a valuable tool to study and optimize their overall performance during the design and set-up phases. Along with Quasi-Steady-State optimization, optimal control (OC) is the most utilized technique to simulate the control and states of a vehicle during minimum-time maneuvers and has been used for offline lap-time optimization for more than twenty years now. Since the first applications of optimal control in this field, it has been clear that the solution of the minimum-time optimization does not represent a model of the human driver but instead substitutes him/her. However, the common points or divergences between the minimum-time strategy of human race drivers and the OC one are still unclear. Moreover, it seems that in the literature there is no agreement about what vehicle models must be used, and in general the choice of one model or the other is not clearly justified. Finally, thanks to the rise in popularity of autonomous driving and racing, optimal control has been used as path planner for automated vehicles: %nonetheless, the application of free-trajectory real-time nonlinear optimal control in Model Predictive Control (MPC) schemes, where the optimal controls are directly fed to the vehicle, is still an unexplored topic. nonetheless, the application of free-trajectory real-time nonlinear optimal control in Model Predictive Control (MPC) schemes, where the optimal controls are computed from a single optimization and directly fed to the vehicle, is a topic still open for exploration. The first aim of this thesis is to provide an objective comparison of several vehicle, tire, powertrain and road models to be used in minimum-time OC. In the first part of this work we thus detail several models of the vehicle and its subsystems. We then solve minimum-time OC problems on a series of test tracks adopting most of the model combinations and discuss the differences in the solutions. We then draw conclusions on the best model combinations to obtain realistic and reliable minimum-time maneuvers. The second part of the thesis aims to prove that the solutions of minimum-time OC problems are indeed different from the driving behavior of professional drivers, but they can be employed to coach the human driver and improve his/her racing performance. After modeling a high-performance vehicle manufactured by Ferrari, we again use optimal control to compute minimum-time maneuvers on two different tracks. A professional racer driving is then coached in following the OC strategy on the Ferrari driving simulator, and we objectively prove that the driver can outperform his previous lap times.
In the third and last part of the thesis, we aim to prove that free-trajectory real-time optimal control is a valid alternative to hierarchical MPC frameworks based on high-level path planning and low-level path tracing. We first develop a novel kineto-dynamic vehicle model able to satisfy the trade-off between computational lightness and accuracy in representing the vehicle's pure and combined dynamics. Then, by solving a minimum-time OC in real-time, we are able to autonomously drive a real scaled vehicle around a track at the limits of tire adherence.
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The effect of the tempo of music on concentration in a simulated driving experienceVenter, Henriette 02 1900 (has links)
Performing multiple tasks simultaneously is proposed to have an influence on the
amount of mental resources available for attending to incoming stimuli’s.
Concentration is presumed to be divided between focussing on driving (incoming
visual information) while attending to incoming auditory information. The study aimed
to investigate the influence of the tempo of music on concentration and driving ability
by means of simulation. Concentration was measured by driving errors (DE)
whereas driving ability was measured by lap-times (LT) and elicited behaviour. Four
treatment conditions were utilised; that is a no-music (NM) control condition, low
tempo music (LTM)-, medium tempo music (MTM)- and high tempo music (HTM)
treatment conditions. Results found that the tempo of music does not have an
influence on concentration; however, significant results were obtained indicating that
the tempo of music does have an influence on driving behaviour. / Psychology / M.A. Soc. Sc. (Psychology)
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Optimal control and stability of four-wheeled vehiclesMasouleh, Mehdi Imani January 2017 (has links)
Two vehicular optimal control problems are visited. The first relates to the minimum lap time problem, which is of interest in racing and the second the minimum fuel problem, which is of great importance in commercial road vehicles. Historically, minimum lap time problems were considered impractical due to their slow solution times compared with the quasi-steady static (QSS) simulations. However, with increasing computational power and advancement of numerical algorithms, such problems have become an invaluable tool for the racing teams. To keep the solution times reasonable, much attention still has to be paid to the problem formulation. The suspension of a Formula One car is modelled using classical mechanics and a meta-model is proposed to enable its incorporation in the optimal control problem. The interactions between the aerodynamics and the suspension are thereby studied and various related parameters are optimised. Aerodynamics plays a crucial role in the performance of Formula One cars. The influence of a locally applied perturbation to the aerodynamic balance is investigated to determine if a compromise made in design can actually lead to lap time improvements. Various issues related to minimum lap time calculations are then discussed. With the danger of climate change and the pressing need to reduce emissions, improvements in fuel consumption are presently needed more than ever. A methodology is developed for fuel performance optimisation of a hybrid vehicle equipped with an undersized engine, battery and a flywheel. Rather than using the widely used driving cycles, a three-dimensional route is chosen and the optimal driving and power management strategy is found with respect to a time of arrival constraint. The benefits of a multi-storage configuration are thereby demonstrated. Finally, the nonlinear stability of a vehicle model described by rational vector fields is investigated using region of attraction (RoA) analysis. With the aid of sum-of-squares programming techniques, Lyapunov functions are found whose level sets act as an under-approximation to the RoA. The influence of different vehicle parameters and driving conditions on the RoA is studied.
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The effect of the tempo of music on concentration in a simulated driving experienceVenter, Henriette 02 1900 (has links)
Performing multiple tasks simultaneously is proposed to have an influence on the
amount of mental resources available for attending to incoming stimuli’s.
Concentration is presumed to be divided between focussing on driving (incoming
visual information) while attending to incoming auditory information. The study aimed
to investigate the influence of the tempo of music on concentration and driving ability
by means of simulation. Concentration was measured by driving errors (DE)
whereas driving ability was measured by lap-times (LT) and elicited behaviour. Four
treatment conditions were utilised; that is a no-music (NM) control condition, low
tempo music (LTM)-, medium tempo music (MTM)- and high tempo music (HTM)
treatment conditions. Results found that the tempo of music does not have an
influence on concentration; however, significant results were obtained indicating that
the tempo of music does have an influence on driving behaviour. / Psychology / M.A. Soc. Sc. (Psychology)
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Däckmodellering och prestandaanalys för Formula StudentOlsson, Hugo January 2024 (has links)
Arbetets syfte var att göra ett motiverat val av däck till bilen som KTH Formula Student planerar att utveckla till 2025. Detta gjordes genom att använda däckdata från FSAE TTC och utifrån den modellera alla däck med däckmodellen Magic Formula TNO MFTyre/MF-Swift 6.1. Denna modell innehåller variationer i däcktryck, camber och vertikal last. Därefter simulerades varvtid vid olika grenar som skidpad, autocross och endurance för att jämföra alla däcks prestanda. Dessutom kunde flera andra värden värda att jämföras beräknas utifrån däckmodellen och datan från FSAE TTC. Dessa var hållbarhet, däcktemperatur, däckens massa, sidkraftskoefficient, camberkänslighet och däckens fjäderkonstant. Alla dessa värden jämfördes till sist där varvtid och hållbarhet prioriterades. Tre däck fanns kvar i slutet vilka rekommenderades.
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