This dissertation proposes an Intelligent Energy Management Agent (IEMA) for parallel hybrid vehicles. A key concept adopted in the development of an IEMA is based on the premise that driving environment would affect fuel consumption and pollutant emissions, as well as the operating modes of the vehicle and the driver behavior do. IEMA incorporates a driving situation identification component whose role is to assess the driving environment, the driving style of the driver, and the operating mode (and trend) of the vehicle using long and short term statistical features of the drive cycle. This information is subsequently used by the torque distribution and charge sustenance components of IEMA to determine the power split strategy, which is shown to lead to improved fuel economy and reduced emissions.

A novel torque control algorithm, which adopts a two-phase excitation, is proposed to improve the performance of the Switched Reluctance Motor (SRM) drive. By exciting two adjacent phases instead of single phase, the changing rate and the magnitude of the phase currents are much reduced. Therefore the existing problems caused by the single-phase excitation such as large torque ripple during commutation, increased audible noise and fatigue of the rotor shaft are mitigated. The electromagnetic torque is efficiently distributed to each phase by the proposed Torque Distribution Function (TDF) that also compensates the effects of mutual coupling. To describe the effects of mutual coupling between phases, a set of voltage and torque equations is newly derived for the two-phase excitation. Parameters of the SRM are obtained by Finite Element Analysis (FEA) and verified by measurements. It is shown that the mutual inductance of two adjacent phases partly contributes to generate the electromagnetic torque and introduces coupling between two adjacent phases in the current or flux linkage control loop, which has been neglected in the single-phase excitation. The dynamics of the current or flux linkage loop are coupled and nonlinear due to the mutual inductance between two adjacent phases and the time varying nature of inductance. Each phase current or flux linkage needs to be controlled precisely to achieve the required performance. A feedback linearizing current controller is proposed to linearize and decouple current control loop along with a gain scheduling scheme to maintain performance of the current control loop regardless of rotor position as well as a feedback linearizing flux linkage controller. Finally, to reduce current or flux linkage ripple, a unipolar switching strategy is proposed. The unipolar switching strategy effectively doubles the switching frequency without increasing the actual switching frequency of the switches. This contributes to the mitigation of current or flux linkage ripple and hence to the reduction of the torque ripple. / Ph. D.

This study describes the development of the Propulsion Supervisory Controller for an independent axle All-Wheel Drive Electric Vehicle, using a model-based approach. The vehicle has a main rear motor and a smaller front motor. Features like power moding, transmission range selection and torque architecture are discussed. For the torque architecture, different torque distribution strategies are explored in detail. Initially, a comparison of torque distribution strategies considering positive torques only, is used to assess the impact on the vehicle's energy consumption. Firstly, an optimal strategy with and without power-rate penalties is explored, which distributes the torque request to minimize the losses in both drive-units. Secondly, a fixed-ratio strategy is considered where both axles contribute with a predetermined torque ratio to meet the total torque demand. Thirdly, a torque-assist approach is examined, wherein only the rear motor contributes to the torque demand till it is operating at instantaneous maximum torque, after which the front motor starts contributing. Similar evaluations are then performed including regenerative braking or negative torque domain. Additionally, the performance of the penalized optimal strategy (PO) for positive torques is evaluated when combined with the torque assist regenerative braking strategy, where the front motor is primarily used for regenerative braking. The performance of PO combined with the ideal regenerative braking strategy is also assessed. This study aims to provide an overview of the controller development approach and an insight of the feasibility of deploying sophisticated computational algorithms for enhanced efficiency on it. / Master of Science / This study focuses on the development of a propulsion controller for a modified all-electric 2023 Cadillac LYRIQ. The Sport Utility Vehicle (SUV) is equipped with a main rear motor and a smaller front motor. Functional features such as the power-up and power-down sequence and vehicle range selection are discussed along with performance features like torque control. The objective is to enable safe vehicle functionality and enhance the vehicle's powertrain efficiency through the development of software for its Propulsion Supervisory Controller (PSC). The study initially evaluates various strategies for distributing torque during forward acceleration. Three primary strategies are analyzed: an optimal approach aimed at minimizing overall energy losses, a fixed-ratio strategy where torque ratios are predetermined to meet the total demand, and a torque-assist method where the front motor provides torque only after the rear motor reaches its instantaneous maximum torque, triggered by the accelerator pedal input exceeding a threshold. Similarly, these strategies are examined within the context of regenerative braking to assess their impact on range. Finally, the penalized optimal torque distribution strategy is combined with a torque assist regenerative braking strategy as well as a strategy that adheres to the ideal braking distribution. This study provides an overview of the vehicle controller development and demonstrates the feasibility and benefits of employing advanced computational algorithms in the propulsion controller to achieve enhanced efficiency and an improved range in electric vehicles.

No description available.

Our society is heavily and intrinsically dependent on energy transformation and usage. In a world scenario where resources are being depleted while their demand is increasing, it is crucial to optimize every process. During the last decade the concept of energy efficiency has become a leitmotif in several fields and has directly influenced our everyday life: from light bulbs to airplane turbines, there has been a general shift from pure performance to better efficiency. In this vein, we focus on the mobility and tractive efficiency of off-road vehicles. These vehicles are adopted in military, agriculture, construction, exploration, recreation, and mining applications and are intended to operate on soft, deformable terrain. The performance of off-road vehicles is deeply influenced by the tire-soil interaction mechanism. Soft soil can drastically reduce the traction performance of tires up to the point of making motion impossible. In this study, a tire model able to predict the performance of rigid wheels and flexible tires is developed. The model follows a semi-empirical approach for steady-state conditions and predicts basic features, such as the drawbar pull, the driving torque and the lateral force, as well as complex behaviors, such as the slip-sinkage phenomenon and the multi-pass effect. The tractive efficiency of different tire-soil configurations is simulated and discussed. To investigate the handling and the traction efficiency, the tire model is implemented into a four-wheel vehicle model. Several tire geometries, vehicle configurations (FWD, RWD, AWD), soil types, and terrain profiles are considered to evaluate the performance under different simulation scenarios. The simulation environment represents an effective tool to realistically analyze the impact of tire parameters (size, inflation pressure) and torque distribution on the energy efficiency. It is verified that larger tires and decreased inflation pressure generally provide better traction and energy efficiency (under steady-state working conditions). The torque distribution strategy between the axles deeply affects the traction and the efficiency: the two variables can't clearly be maximized at the same time and a trade-off has to be found. / Ph. D.

The work presented in this thesis aims to make contribution to the understanding and application of six-legged statically stable walking machines in both theoretical and practical levels. In this thesis five pieces of work, performed with and for the three-joint six-legged Robot-EA308, are presented: 1) Standard gaits, which include the well-known wave gaits, are defined and a stability analysis, in the sense of static stable walking, is performed on an analytical level. Various definitions are given / theorems are stated and proved. 2) A free gait generation algorithm with reinforcement learning is developed. Its facilities of stability improvement, smooth speed changes, and adaptation in case of a rear-leg deficiency with learning of five-legged walking are experimented in real-time on the Robot-EA308. 3) Trajectory optimization and controller design is performed for the protraction movement of a three-joint leg. The trajectory generated by the controller is demonstrated with the Robot-EA308. 4) The full kinematic-dynamic formulation of a three-joint six-legged robot is performed with the joint-torques being the primary variables. It is demonstrated that the proposed torque distribution scheme, rather than the conventional force distribution, results in an efficient distribution of required forces and moments to the supporting legs. 5) An analysis of energy efficiency is performed for wave gaits. The established strategies for determination of gait parameters for an efficient walk are justified using the Robot-EA308.

No description available.

Moderne Kraftfahrzeuge werden mit einer Vielzahl von Fahrerassistenzsystemen ausgestattet um die Sicherheit, die Traktion, die Energieeffzienz, die Agilität und den Komfort noch weiter zu verbessern. Diese Ziele können zu einem Großteil mit einer aktiven Drehmomentverteilung, auch Torque Vectoring genannt, erreicht werden. Dafür sind jedoch Getriebesysteme erforderlich, welche unabhängig vom Fahrzustand und vom Antriebsmoment eine nahezu beliebige Drehmomentverteilung ermöglichen. In der vorliegenden Arbeit werden zunächst Grundlagen zu Getriebesystemen, insbesondere zu Planetengetrieben, und zur Fahrzeugdynamik erläutert. Anschließend wird der Stand der Technik anhand einer Systematik zur Einteilung von aktiven Differenzialgetrieben dargelegt sowie einige Vor- und Nachteile aufgezeigt. Das folgende Kapitel stellt ein Verfahren zur Ermittlung der mechanischen Belastung des aktiven Differenzialgetriebes für beliebige Fahrzeuge und Strecken vor. Damit erfolgt eine Bewertung der bisher bekannten Systeme hinsichtlich Gesamtwirkungsgrad, konstruktiver Aufwand und regelungstechnische Eigenschaften. Im Anschluss wird ein Verfahren zur rechnergestützten Synthese neuer Getriebesysteme beschrieben. Abschließend werden die positiven Auswirkungen der aktiven Drehmomentverteilung auf die Fahrdynamik herausgestellt. Das Ergebnis der Arbeit zeigt drei neue Getriebestrukturen, welche anhand der deffinierten Vergleichskriterien besser sind als alle bekannten Systeme. / Actual passenger cars are equipped with a lot of driver assistant systems to increase safety, traction, efficiency, agility and comfort. These aims can be achieved by a controlled transmission of the engine torque to each driven wheel (active torque distribution, Torque Vectoring). Therefore special gear systems are necessary. In this document firstly the basics on gear systems (planetary gears) and vehicle dynamics are explained. Furthermore the state of the art is shown based on a classification of active differentials and the advantages and disadvantages are envinced. The next chapter describes a method for determining the mechanic load of the active differential for any car and road track. This is used for an evaluation of every differential gear system in view of efficiency, mechanic effort and control properties. The result reveals significant differences between the gear structures. Subsequent a method for a computer synthesis of new gear systems is developped and applied to the demands of a front driven vehicle application. The last chapter points out the positive effects of an active torque distribution on the driving dynamics. As a result of this work three new gear structures are shown which are much better than all existing gear systems in terms of the evaluation properties.

Moderne Kraftfahrzeuge werden mit einer Vielzahl von Fahrerassistenzsystemen ausgestattet um die Sicherheit, die Traktion, die Energieeffzienz, die Agilität und den Komfort noch weiter zu verbessern. Diese Ziele können zu einem Großteil mit einer aktiven Drehmomentverteilung, auch Torque Vectoring genannt, erreicht werden. Dafür sind jedoch Getriebesysteme erforderlich, welche unabhängig vom Fahrzustand und vom Antriebsmoment eine nahezu beliebige Drehmomentverteilung ermöglichen. In der vorliegenden Arbeit werden zunächst Grundlagen zu Getriebesystemen, insbesondere zu Planetengetrieben, und zur Fahrzeugdynamik erläutert. Anschließend wird der Stand der Technik anhand einer Systematik zur Einteilung von aktiven Differenzialgetrieben dargelegt sowie einige Vor- und Nachteile aufgezeigt. Das folgende Kapitel stellt ein Verfahren zur Ermittlung der mechanischen Belastung des aktiven Differenzialgetriebes für beliebige Fahrzeuge und Strecken vor. Damit erfolgt eine Bewertung der bisher bekannten Systeme hinsichtlich Gesamtwirkungsgrad, konstruktiver Aufwand und regelungstechnische Eigenschaften. Im Anschluss wird ein Verfahren zur rechnergestützten Synthese neuer Getriebesysteme beschrieben. Abschließend werden die positiven Auswirkungen der aktiven Drehmomentverteilung auf die Fahrdynamik herausgestellt. Das Ergebnis der Arbeit zeigt drei neue Getriebestrukturen, welche anhand der deffinierten Vergleichskriterien besser sind als alle bekannten Systeme.:1 Einleitung 2 Grundlagen 2.1 Getriebesysteme 2.2 Fahrdynamik 3 Stand der Technik 3.1 Getriebesysteme 3.2 Fahrdynamikregelung 4 Analyse bekannter Getriebesysteme 4.1 Zeitlicher Verlauf fahrdynamischer Größen 4.2 Systematische Analyse von Planetengetrieben 4.3 Deffinition der Vergleichskriterien 4.4 Differenziallose Systeme 4.5 Differenzialsysteme 4.6 Elektromotorische Systeme 4.7 Sonderbauformen 4.8 Vergleich bekannter Systeme 5 Synthese neuer Getriebestrukturen 5.1 Anforderungen an aktive Differenzialgetriebe 5.2 Manuelle Struktursynthese 5.3 Rechnergestützte Struktursynthese 5.4 Ergebnisse der Struktursynthese 6 Auswirkung von aktiver Drehmomentverteilung auf die Fahrdynamik 6.1 Komplexe Fahrdynamiksimulation 6.2 Steigerung der Traktion 6.3 Steigerung der Agilität 6.4 Steigerung der Fahrstabilität 6.5 Steigerung des Fahrkomforts 6.6 Verringerung des Kraftstoffverbrauches Zusammenfassung und Ausblick Literaturverzeichnis / Actual passenger cars are equipped with a lot of driver assistant systems to increase safety, traction, efficiency, agility and comfort. These aims can be achieved by a controlled transmission of the engine torque to each driven wheel (active torque distribution, Torque Vectoring). Therefore special gear systems are necessary. In this document firstly the basics on gear systems (planetary gears) and vehicle dynamics are explained. Furthermore the state of the art is shown based on a classification of active differentials and the advantages and disadvantages are envinced. The next chapter describes a method for determining the mechanic load of the active differential for any car and road track. This is used for an evaluation of every differential gear system in view of efficiency, mechanic effort and control properties. The result reveals significant differences between the gear structures. Subsequent a method for a computer synthesis of new gear systems is developped and applied to the demands of a front driven vehicle application. The last chapter points out the positive effects of an active torque distribution on the driving dynamics. As a result of this work three new gear structures are shown which are much better than all existing gear systems in terms of the evaluation properties.:1 Einleitung 2 Grundlagen 2.1 Getriebesysteme 2.2 Fahrdynamik 3 Stand der Technik 3.1 Getriebesysteme 3.2 Fahrdynamikregelung 4 Analyse bekannter Getriebesysteme 4.1 Zeitlicher Verlauf fahrdynamischer Größen 4.2 Systematische Analyse von Planetengetrieben 4.3 Deffinition der Vergleichskriterien 4.4 Differenziallose Systeme 4.5 Differenzialsysteme 4.6 Elektromotorische Systeme 4.7 Sonderbauformen 4.8 Vergleich bekannter Systeme 5 Synthese neuer Getriebestrukturen 5.1 Anforderungen an aktive Differenzialgetriebe 5.2 Manuelle Struktursynthese 5.3 Rechnergestützte Struktursynthese 5.4 Ergebnisse der Struktursynthese 6 Auswirkung von aktiver Drehmomentverteilung auf die Fahrdynamik 6.1 Komplexe Fahrdynamiksimulation 6.2 Steigerung der Traktion 6.3 Steigerung der Agilität 6.4 Steigerung der Fahrstabilität 6.5 Steigerung des Fahrkomforts 6.6 Verringerung des Kraftstoffverbrauches Zusammenfassung und Ausblick Literaturverzeichnis