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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the 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.
11

Robust Torque Control for Automated Gear Shifting in Heavy Duty Vehicles / Robust Momentreglering vid Automatiserad Växling i Tunga Fordon

Abrahamsson, Henrik, Carlson, Peter January 2008 (has links)
In an automated manual transmission it is desired to have zero torque in the transmission when disengaging a gear. This minimizes the oscillations in the driveline which increases the comfort and makes the speed synchronization easier. The automated manual transmission system in a Scania truck, called Opticruise, uses engine torque control to achieve zero torque in the transmission.In this thesis different control strategies for engine torque control are proposed in order to minimize the oscillations in the driveline and increase the comfort during a gear shift. A model of the driveline is developed in order to evaluate the control strategies. The main focus was to develop controllers that are easy to implement and that are robust enough to be used in different driveline configurations. This means that model dependent control strategies are not considered.A control strategy with a combination of a feedback from the speed difference between the output shaft speed and the wheel speed, and a feedforward with a linear ramp, showed very good performance in both simulations and tests in trucks. The amplitude of the oscillations in the output shaft speed after neutralengagement are halved compared to the results from the existing method in Scania trucks. The new concept is also more robust against initial conditions and time delay estimations.
12

Jackknife stability of articulated tractor semitrailer vehicles with high-output brakes and jackknife detection on low coefficient surfaces

Dunn, Ashley L. 14 October 2003 (has links)
No description available.
13

Modeling and Validation of a Heavy Truck Model with Electronic Stability Control

McNaull, Patrick James 25 September 2009 (has links)
No description available.
14

Etude du flux de soubassement sur la dynamique du sillage d'un corps non profilé à culot droit : Application du contrôle actif pour la réduction de traînée de véhicule industriel

Szmigiel, Mathieu 05 May 2017 (has links)
Cette thèse CIFRE est le fruit d’une collaboration entre Renault Trucks et le LMFA dans la perspective d’une évaluation de la pertinence du contrôle actif pour la réduction de traînée de véhicule industriel. Les deux principaux objectifs de ces travaux expérimentaux consistent à l’analyse de l’influence de l’écoulement de soubassement sur la dynamique du sillage et l’étude d’une stratégie de contrôle d’écoulement combinant des volets déflecteurs (positionnés sur les bords supérieurs et latéraux du culot) à des actionneurs de type jets pulsés dans l’optique d’une réduction de la traînée aérodynamique d’un corps non profilé à culot droit. Le développement du sillage pour différentes vitesses de soubassement évoluant de 10% à plus de 80% de la vitesse de l’écoulement infini amont est étudié sur une maquette simplifiée de véhicule poids lourd à l’échelle 1/43e. Des mesures de pression au culot permettent d’identifier quatre classes d’écoulement associées à des structures de sillage différentes mises en évidence par des mesures PIV 2D-3C. Le sillage de la première classe d’écoulement obtenu pour les très faibles vitesses de soubassement ressemble au sillage derrière une marche 3D. Pour des vitesses de soubassement plus élevées, l’écoulement de soubassement décolle au niveau du sol et impacte soit le culot ou soit la couche de cisaillement supérieure favorisant le développement des instabilités de type Kelvin-Helmoltz dans ce dernier cas. Enfin, la dernière classe est caractérisée par un sillage comparable à celui d’un corps d’Ahmed. L’ajout de volets déflecteurs à l’arrière du culot engendre une augmentation de la pression au culot pour l’ensemble des classes d’écoulement. Cette augmentation réside principalement dans l’effet de vectorisation de l’écoulement. Un système de contrôle actif est intégré sur une maquette 1/8e géométriquement identique à celle à l’échelle 1/43e et équipée de volets déflecteurs. Deux angles de volet supérieur sont testés afin d’obtenir en moyenne (i) un écoulement naturel attaché à la paroi du volet et (ii) un écoulement naturel détaché du volet. Par rapport au cas sans contrôle actif, des gains sur la traînée sont obtenus pour une certaine gamme de fréquence d’actionnement uniquement dans le cas (ii). Ces gains sont obtenus suite au recollement de l’écoulement sur le volet. Enfin, la robustesse des gains sur la pression au culot est testée avec succès en mettant la maquette en dérapage pour simuler un vent de travers. / This PhD thesis was realized in the scope of a collaboration with Renault Trucks and the LMFA in view of an evaluation of the relevance of active flow control for the drag reduction industrial vehicle. The two main objectives of this experimental work are to analyze the impact of the underbody flow on the wake dynamics and to study a flow control strategy combining inclined flaps (located on the upper and lateral edges of the rear base) with pulsed jet actuators for reducing the aerodynamic drag of a square-back bluff body. The wake development for several underbody velocities ranging from 10% to more than 80% of the free-stream velocity is studied on a simplified truck model at scale 1 :43. Rear base pressure measurements lead to the identification of four flow classes associated with different wake structures highlighted by 2D-3C PIV measurements. The wake of the first flow class obtained for very low underbody velocities looks like that of the wake of a 3D backward facing step. For higher underbody velocities, the underbody flow is separated from the ground impaging either the rear base or the upper shear layer triggering Kelvin-Helmoltz instabilities for this last case. Finally, the fourth class is characterized by a wake comparable to that of the Ahmed body. The implementation of inclined flaps at the rear base increases the base pressure for all classes. This increase is mainly due to the vectoring effect of the flow. An active control system is integrated to a 1 :8 scale model geometrically identical to that of the 1 :43 scale model with flaps. Two upper flap angles are tested to have (i) a natural flow attached to the flap and (ii) a natural flow detached from the flap. In comparison to the case without active flow control, drag reductions are obtained only for a specific range of actuation frequencies only in case (ii). These gains are associated with the reattachment of the flow on the flap. Finally, the robustness of the pressure gains is successfully tested in crosswind conditions.
15

Fuel Consumption and Emissions of Turnpike Doubles in the Canadian Prairie Region

Baumgartner, Thomas Peter 06 April 2011 (has links)
This research analyzes fuel consumption and emissions of Turnpike double trailer combinations (Turnpikes) on a regional network in the Canadian Prairies. The research: (1) establishes current benchmarks for fuel consumption of Turnpikes and five-axle tractor semitrailers (3-S2s) with van trailers; (2) develops fuel consumption models for these vehicle types; (3) establishes an understanding of current operating characteristics of Turnpikes in the region; and (4) estimates their system-wide effects in terms of fuel consumption and emissions in Manitoba by applying the developed models. Canadian Prairie region-based carriers revealed an increase in Turnpike travel (from 2007-2009) of 44 percent after the twinning of the Trans-Canada Highway between Winnipeg and Regina in 2007 was completed. Turnpikes can save one third of fuel consumed when compared to 3-S2s; have higher fuel consumption in the winter months; and their use in 2009 reduced fuel consumption and CO2 emissions by five percent compared to 3-S2s.
16

Fuel Consumption and Emissions of Turnpike Doubles in the Canadian Prairie Region

Baumgartner, Thomas Peter 06 April 2011 (has links)
This research analyzes fuel consumption and emissions of Turnpike double trailer combinations (Turnpikes) on a regional network in the Canadian Prairies. The research: (1) establishes current benchmarks for fuel consumption of Turnpikes and five-axle tractor semitrailers (3-S2s) with van trailers; (2) develops fuel consumption models for these vehicle types; (3) establishes an understanding of current operating characteristics of Turnpikes in the region; and (4) estimates their system-wide effects in terms of fuel consumption and emissions in Manitoba by applying the developed models. Canadian Prairie region-based carriers revealed an increase in Turnpike travel (from 2007-2009) of 44 percent after the twinning of the Trans-Canada Highway between Winnipeg and Regina in 2007 was completed. Turnpikes can save one third of fuel consumed when compared to 3-S2s; have higher fuel consumption in the winter months; and their use in 2009 reduced fuel consumption and CO2 emissions by five percent compared to 3-S2s.
17

Vehicle thermal management control systems / Systèmes de contrôle pour la gestion thermique d'un vehicule

Sermeno Mena, Salvador 16 June 2015 (has links)
Les systèmes de refroidissement des véhicules continuent à se développer et devenir de plus en plus complexes. Ceci introduit des nouveaux problèmes dus aux interactions des composants et les perturbations du système. Avec la montée des prix des carburants; les développeurs et les compagnies cherchent à améliorer la consommation en respectant les normes d’émission. Une partie de l’énergie produite par le moteur est utilisé par les composants du circuit de refroidissement. L’utilisation d’auxiliaires électriques est une manière de réduire ces pertes parasites, mais ce n’est pas la seule solution. Des études récents proposent que un control plus adaptes des composants peux réduire la consommation de carburant. Actuellement, le groupe Volvo en essayant d’améliorer la performance du système de refroidissement des camions a installe des nouveaux composants pour la gestion thermique du moteur. Néanmoins, des problèmes ont été identifie lors d’essais véhicule. Une meilleure compréhension du système et de l’implémentation de composants est nécessaire pour limiter les effets non voulus. Le système de refroidissement d’un poids lourd a été étudié grâce à l’outil Bond Graph. Puis des nouvelles stratégies de control sont introduites : commande prédictive, commande par platitude, commande sans model et commande avec model réduit. Ces méthodes ont été implémentées dans une plateforme de simulation sur Matlab/Simulink. Les gains de consommation obtenue à partir de simulations sont entre 0.5 et 0.9%. Une analyse structurelle de l’architecture actuelle est présentée. D’après les conclusions de cette analyse, des propositions pour la modification de l’architecture du circuit sont évalués. / The increasing complexity of engine cooling systems results in added interactions and disturbances to the performance. Besides, non-propulsion loads (fan, water pump…) draw a significant percentage of the engine’s power thus lowering the vehicle’s fuel efficiency. Recent studies have shown that by controlling components the efficiency can be improved by adjusting fan speed according to cooling needs, coolant flow, and oil flow. Currently, the Volvo group in order to optimize the performance of their truck’s cooling systems had installed new thermal management components. However, problems were found while testing control strategies and a better understanding of the interaction between components is required to prevent this from happening again. In this work, the bond graph approach has been applied for the study of the cooling system of a Heavy duty vehicle and has enabled subsystem interactions to be identified. Based on a simplified model issued from the bond graph, several control strategies have been built. These controllers are based on different control approaches: model predictive control, flatness control, model free control and model free control with reduced order model. These controllers were implemented in a simulation platform in the Matlab/Simulink environment. Results of the implementation of the new advanced control strategies are given. Fuel economy gains ranged between 0.5 and 0.9 %. A structural analysis of the current architecture is also proposed aiming at the optimization of the system. Given the insights from the analysis, an assessment of new concepts for the cooling system architecture is proposed.
18

Development of a Heavy Truck Vehicle Dynamics Model using Trucksim and Model Based Design of ABS and ESC Controllers in Simulink

Rao, Shreesha Yogish 11 July 2013 (has links)
No description available.
19

Sharing Sales and Service Networks with Competitors : A Multiple-case Study in the Heavy Truck Industry / Att dela sälj- och servicenätverk med konkurrenter

ENGBLOM, ALEXANDER, LUNDQUIST, EMMA January 2018 (has links)
In the heavy truck industry, sales and service networks play an important role. Investments in network infrastructure are costly, and to be profitable, there is a critical service volume to fulfil. This is especially challenging in new markets, where service demand is low and uncertain. A possible solution is to share sales and service networks with competitors. Simultaneous cooperation and competition, co-opetition, is a complex and contradictory phenomenon that has been previously researched, but with focus on cooperation in input activities like R&D. This thesis investigates co-opetition in output activities, in sales and services, by analysing how heavy truck companies could form competitor partnerships in sales and service networks. This is done by a literature review and a multiple case study. From the analysis, a framework for assessing and designing potential competitor partnerships is presented. The framework consists of seven factors that are significant for competitor partnership success in sales and service networks; cultural fit, noncompeting products, compatible goals, excess network capacity, dedicated salespersons, high commitment, and patient implementation. This thesis contributes to science by research on co-opetition research in output activities, and by a discussion on the meaning of competition, success and partnerships. / I tunga lastbilsbranschen spelar sälj- och servicenätverk en viktig roll. Investeringar i nätverken är dyra, och för att vara lönsamma krävs en viss servicevolym. Det är särskilt utmanande på nya marknader, där efterfrågan är låg och obestämd. En möjlig lösning är att dela sälj- och servicenätverk med konkurrenter. Simultant samarbete och konkurrens, så kallad co-opetition, är ett komplext och motsägande fenomen, som tidigare forskats på med fokus på samarbete inom utveckling. Denna uppsats undersöker co-opetition inom sälj, genom att titta på hur tunga lastbilsföretag kan ingå partnerskap inom sälj- och servicenätverk tillsammans med konkurrenter. Detta görs genom en litteraturgenomgång samt en flerfallstudie. Utifrån vår analys presenteras ett ramverk för att bedöma och utforma potentiella partnerskap med konkurrenter. Ramverket består av sju viktiga faktorer för framgångsrika partnerskap inom sälj- och servicenätverk tillsammans med konkurrenter; kulturell passform (cultural fit), icke-konkurrerande produkter, kompatibla mål, överbliven kapacitet i nätverket, dedikerade säljare, högt engagemang och tålmodig implementering. Uppsatsen bidrar till forskning inom co-opetition inom sälj och med diskussion kring begreppen konkurrens, framgång och partnerskap.
20

Placement of Controls in Construction Equipment Using Operators´Sitting Postures : Process and Recommendations

Jalkebo, Charlotte January 2014 (has links)
An ergonomically designed work environment may decrease work related musculoskeletal disorders, lead to less sick leaves and increase production time for operators and companies all around the world. Volvo Construction Equipment wants to deepen the knowledge and investigate more carefully how operators are actually sitting whilst operating the machines, how this affects placement of controls and furthermore optimize controls placements accordingly. The purpose is to enhance their product development process by suggesting guidelines for control placement with improved ergonomics based on operators’ sitting postures. The goal is to deliver a process which identifies and transfers sitting postures to RAMSIS and uses them for control placement recommendations in the cab and operator environments. Delimitations concerns: physical ergonomics, 80% usability of the resulted process on the machine types, and the level of detail for controls and their placements. Research, analysis, interviews, test driving of machines, video recordings of operators and the ergonomic software RAMSIS has served as base for analysis. The analysis led to (i) the conclusion that sitting postures affect optimal ergonomic placement of controls, though not ISO-standards, (ii) the conclusion that RAMSIS heavy truck postures does not seem to correspond to Volvo CE’s operators’ sitting postures and (iii) and to an advanced engineering project process suitable for all machine types and applicable in the product development process. The result can also be used for other machines than construction equipment. The resulted process consists of three independent sub-processes with step by step explanations and recommendations of; (i) what information that needs to be gathered, (ii) how to identify and transfer sitting postures into RAMSIS, (iii) how to use RAMSIS to create e design aid for recommended control placement. The thesis also contains additional enhancements to Volvo CE’s product development process with focus on ergonomics. A conclusion is that the use of motion capture could not be verified to work for Volvo Construction Equipment, though it was verified that if motion capture works, the process works. Another conclusion is that the suggested body landmarks not could be verified that they are all needed for this purpose except for those needed for control placement. Though they are based on previous sitting posture identification in vehicles and only those that also occur in RAMSIS are recommended, and therefore they can be used. This thesis also questions the most important parameters for interior vehicle design (hip- and eye locations) and suggests that shoulder locations are just as important. The thesis concluded five parameters for control categorization, and added seven categories in addition to those mentioned in the ISO-standards. Other contradictions and loopholes in the ISO-standards were identified, highlighted and discussed. Suggestions for improving the ergonomic analyses in RAMSIS can also be found in this report. More future research mentioned is more details on control placement as well as research regarding sitting postures are suggested. If the resulted process is delimited to concern upper body postures, other methods for posture identification may be used.

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