Causal Tracking Control of a Non-Minimum Phase HIL Transmission Test System

The automotive industry has long relied on testing powertrain components in real vehicles, which causes the development process to be slow and expensive. Therefore, hardware in the loop (HIL) testing techniques are increasingly being adopted to develop electronic control units (ECU) for engine and other components of a vehicle. In this thesis, HIL testing system is developed to provide a laboratory testing environment for continuously variable transmissions (CVTs). Two induction motors were utilized to emulate a real engine and vehicle. The engine and vehicle models, running in real-time, provide reference torque and speed signals for input and output dynamometers, respectively. To design torque and speed tracking controllers, linear models of the motor and drive systems were firstly identified from the test results. Feedforward controllers were then designed according to the inverse dynamics of the identified models. Because of the existence of unstable zeros in the model, design effort was focused on the stability and causality of the inverse process. Digital preview filters were formulated to approximate the stable inverse of unstable zeros as part of the feedforward controller. Normally, future information of input trajectory is required when implementing the digital preview filters, which makes the feedforward controller non-causal. Since the engine and vehicle model require current information to calculate the next output and no future value can be provided in advance, the application of non-causal digital controllers was limited. A novel method is proposed here to apply non-causal digital controllers causally. Robustness of the controllers is also considered when the two motors are coupled and the gear ratio between them was changed. The proposed coupled control method was tested and verified experimentally by using a manual gearbox before recommending its use for a CVT testing. A multifrequency test signal as well as simulation results of a whole vehicle model were used as torque and speed demand signals in the experiments. A HIL testing case was also presented. Frequency and time domain results showed the effectiveness of the method under both testing procedures to fully compensate for the dynamics of both actuators.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Characterisation of the electric drive of EV: on-road versus off-road method

For system design, analysis of global performance and energy management of electric vehicles (EVs), it is common to use the efficiency map of electric traction drive. The characterisation of the efficiency map with high accuracy is then an important issue. In this study, an on-road method and an off-road method are compared experimentally to determine the efficiency map of electric drive of EVs. The off-road method requires a dedicated experimental test bed, which is expensive and time consuming. The on-road method is achieved directly in-vehicle. Experimental data, recorded during an on-road driving cycle, are used to determine the efficiency map using non-intrusive measurements from global positioning system antenna, voltage and current sensors. A versatile experimental setup is used to compare both methods on the same platform. A maximal efficiency difference of 6% is achieved in most of the torque–speed plane. It is shown that, in an energetic point of view, both methods yield similar results. © The Institution of Engineering and Technology 201

DESIGN OF AN ANTI-JERK CONTROLLER FOR BOTH LOCKED AND SLIPPING TORQUE CONVERTER CONDITIONS IN A VEHICLE

With the advancement in the automotive technologies, the customer scrutiny on the ride comfort of automobiles has come to light. Vehicle drivability is one of the important aspects that defines the ride comfort for a vehicle. Drivability of a vehicle is a qualitative measure and may differ from person to person, however, researches have come up to highlight a few parameters that can categorize the drivability performance of a vehicle into good or bad for a majority of the targeted audience. One of those parameters include shuffle, which is defined as the longitudinal oscillations that occurs in the drivetrain when a sudden demand for torque rise or drop is made. Another such parameter is the sluggishness in the delivery of torque at wheels against the requested torque by the driver. This can exist due to the shift in the dynamics during the drivetrain operation from locked torque converter clutch to slipping torque converter clutch. This work addresses both the drivability related issues, namely, shuffle and torque lag mentioned in the preceding para. Initially, the shuffle oscillations generated in a vehicle are analyzed when subjected to a sudden positive to positive driver torque tip-in request. Further, a pre-compensator and feedback controller based control scheme is designed to damp those shuffle oscillations while keeping the torque delivery response fast. This control approach shapes the actuator torque (i.e., an engine or an e-motor) in such a way that the desired response is achieved. Next, the problem of sluggish torque response at wheels due to slipping of the torque converter clutch is addressed. Initially, a model-based feedforward and feedback controller is developed to control the actuator torque such that when the torque converter slips, an extra compensatory torque from the actuator is applied. This compensation torque ensures that the torque response at the turbine and succeeding driveline components up till the wheels is maintained as desired. However, the actuator has some physical limitations in terms of the maximum magnitude and rate of the torque delivery. So, at some instances, the torque request generated by the controller may not be feasible for the actuator to follow. This problem is addressed when another controller, based on model predictive control approach, is proposed. This controller is based on the approach that continuously updates the controller of the torque delivery of the actuator. The controller solves an optimisation problem over the defined constraints of the actuator and plant, and further finds the most feasible response for the actuator to follow within its defined operating range. Later, A comparison between the two controllers showed model predictive controller to be 15.3% better in terms of the propeller shaft torque response than the feedforward and feedback controller, for the problem under discussion

Development of a Simulation based Powertrain Design Framework for Evaluation of Transient Soot Emissions from Diesel Engine Vehicles.

This dissertation presents the development of a modeling and simulation framework for diesel engine vehicles to enable soot emissions as a constraint in powertrain design and control. To this end, numerically efficient models for predicting temporallyresolved transient soot emissions are identified in the form of a third-order dual-input single-output (DISO) Volterra series from transient soot data recorded by integrating real-time (RT) vehicle level models in Engine-in-the-loop (EIL) experiments. It is shown that the prediction accuracy of transient soot significantly improves over the steady-state maps, while the model remains computationally efficient for systemslevel work. The evaluation of powertrain design also requires a systematic procedure for dealing with the issue that drivers potentially adapt their driving styles to a given design. In order to evaluate the implications of different powertrain design changes on transient soot production it is essential to compare these design changes on a consistent basis. This problem is explored in the context of longitudinal motion of a vehicle following a standard drive-cycle repeatedly. This dissertation develops a proportional-derivative (PD) type iterative learning based algorithm to synthesize driver actuator inputs that seek to minimize soot emissions using the Volterra series based transient soot models. The solution is compared to the one obtained using linear programming. Results show that about 19% reduction in total soot can be achieved for the powertrain design considered in about 40 iterations. The two contributions of this dissertation: development of computationally efficient system level transient soot models and the synthesis of driver inputs via iterative learning for reducing soot, both contribute to improving the art of modeling and simulation for diesel powertrain design and control.Ph.D.Mechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/86386/1/ahlawatr_1.pd

Approche systémique pour la modélisation, la gestion de l'énergie et l'aide au dimensionnement des véhicules hybrides thermiques-électriques

The Hybrid Electric Vehicle is a complex system made up of several sources and the arrangement of its transmission can appeal to several components. The possibility of having different sizes of the battery compared to the combustion engine, coupled with the various possible topologies, represent as many degrees of freedom that can be exploited for its energy optimization. The first chapter of this paper exposes this diversity by presenting the different common classifications of hybrid electric vehicles. Apart from a few applications that are intended to increase the dynamic performance of the vehicle (speed and acceleration), the goal of hybridization is mainly the reduction of energy consumption and emissions of pollutants. It is the energy target that is considered in this work. To achieve this goal, optimizations are needed on different plans. For a given use, the energy performance of the hybrid vehicle depends on three strongly interdependent aspects which are i) topology (series, parallel, dual) ii) the sizing of components iii) energy management strategy to share the instantaneous power demand. To understand these different dimensions and their coupling, a systemic approach based on modelling was implemented with the Electric and Hybrid Vehicle team members. This approach has led to the development of a simulation tool, VEHLIB, that allowed to capitalizing different modelling works. This tool, which is presented in the second chapter, has then been used to serve the objectives of the energy management optimization and support the optimal design of hybrid vehicles. Under the MEGEVH network[1] , an opening towards the Energetic Macroscopic Representation (EMR, developed by the L2EP) showed the undeniable contribution of the EMR to the systematic synthesis of complex systems' control. Chapter III, dedicated to energy management, presents a State of the art of the methods developed these past ten years, and our contribution in this area. The latter was initially in the use and improvement of the rule based methods. Then two theses under my supervision proposed the optimization of the energy management in terms of fuel consumption. All these works relied on an approach using modeling, as well as experimentation on a test bench in an emulated vehicle configuration (Hardware In the Loop - HIL - simulation). Was also highlighted for the hybrid electric vehicles the problem of the relative size of the battery and electrical machines compared to the size of the combustion engine. Indeed, for a given dynamic specifications, several sizing may qualify. A help to the optimal sizing procedure has been implemented in the team and has been the subject of work described in Chapter 4. Theoretically, the general definition of hybrid vehicles is not limited to thermal - electric version which was the subject of the majority of our contributions so far. Other possibilities for association of sources (fuel cell, supercapacitors, flywheel, ...) are being considered and are the subject of recent work. We can speak in this case of multi-source vehicle. Either at topology level or at the level of the energy management and components' sizing, research is still needed to try to generalize the concepts already developed for the hybrid electric vehicle. The use of structuring formalisms like the EMR would help to understand the growing complexity and achieve the articulation between the different levels of control, local and global. On these different dimensions, perspectives and opportunities are detailed in the last chapter of this report.Le véhicule hybride est un système complexe constitué de plusieurs sources et dont l'agencement de sa transmission peut faire appel à plusieurs composants. La possibilité d'avoir des dimensionnements différents de la batterie par rapport au moteur thermique, couplée aux diverses topologies possibles, représentent autant de degrés de liberté qui peuvent être exploités pour son optimisation énergétique. Le premier chapitre de ce mémoire expose cette diversité en présentant les différentes classifications usuelles des Îhicules hybrides. Mises à part quelques applications qui visent à augmenter les performances dynamiques des Îhicules (vitesse et accélération), l'objectif de l'hybridation est principalement la réduction de la consommation énergétique et des émissions de polluants. C'est l'objectif énergétique qu'on considère dans ces travaux. Afin d'atteindre cet objectif, des optimisations sont nécessaires sur différents plans. Pour un usage donné, les performances énergétiques du Îhicule hybride dépendent de trois aspects fortement interdépendants qui sont i) la topologie (série, parallèle, mixte) ii) le dimensionnement des composants iii) la stratégie de gestion de l'énergie entre les différentes sources. Pour appréhender ces différentes dimensions et leur couplage, une approche systémique s'appuyant sur la modélisation a été mise en place avec les membres de l'équipe Véhicules électriques et hybrides du LTE. Cette approche a abouti au développement d'un outil de simulation, VEHLIB, qui a permis de capitaliser les différents travaux de modélisation. Cet outil, présenté dans le deuxième chapitre, a été utilisé ensuite pour servir les objectifs d'optimisation de la gestion de l'énergie et d'aide au dimensionnement optimal des Îhicules hybrides. Dans le cadre du réseau MEGEVH , une ouverture vers la Représentation Energétique Macroscopique (REM, développée au L2EP) a permis de démontrer l'apport incontestable de la REM pour la synthèse systématique de la commande des systèmes. Le chapitre III, consacré à la gestion de l'énergie, présente un état de l'art des méthodes développées ces dix dernières années, ainsi que notre contribution dans ce domaine. Cette dernière a consisté dans un premier temps en l'utilisation et l'amélioration des méthodes à base de règles expertes. Ensuite deux thèses ont proposé l'optimisation de la gestion de l'énergie de point de vue de la consommation de carburant. Tous ces travaux se sont appuyés sur une démarche utilisant la modélisation, ainsi que l'expérimentation sur banc d'essai à l'échelle 1 dans une configuration de Îhicule émulé (Hardware In the Loop - HIL - simulation). Il s'est posé également, pour le Îhicule hybride, le problème de la taille relative de la batterie et des machines électriques vis-à-vis de la taille du moteur thermique. En effet, pour un cahier des charges dynamique donné, plusieurs dimensionnements peuvent être admissibles. Une procédure d'aide au dimensionnement optimal a été mise en oeuvre dans l'équipe et a fait l'objet de travaux exposés dans le chapitre 4. En théorie, la définition générale du Îhicule hybride ne se limite pas à la version thermique - électrique qui a fait l'objet de la plus part de nos contributions jusqu'ici. D'autres possibilités d'association de sources (Pile à combustible, supercondensateurs, volent d'inertie, ...) sont envisagées et font l'objet de travaux récents. On peut parler dans ce cas de Îhicule multi-sources. Tant au niveau des topologies, qu'au niveau de la gestion de l'énergie et du dimensionnement, des travaux de recherches sont encore nécessaires pour tenter de généraliser les concepts déjà développés pour le Îhicule hybride thermique-électrique. L'utilisation de formalismes structurants à l'image de la REM permettrait d'appréhender la complexité croissante et de réaliser l'articulation entre les différents niveaux de commande, locale et globale. Sur ces différentes dimensions, des ouvertures et des perspectives sont détaillées dans le dernier chapitre de ce mémoire

An object-oriented modelling method for evolving the hybrid vehicle design space in a systems engineering environment

A combination of environmental awareness, consumer demands and pressure from legislators has led automotive manufacturers to seek for more environmentally friendly alternatives while still meeting the quality, performance and price demands of their customers. This has led to many complex powertrain designs being developed in order to produce vehicles with reduced carbon emissions. In particular, within the last decade most of the major automotive manufactures have either developed or announced plans to develop one or more hybrid vehicle models. This means that to be competitive and o er the best HEV solutions to customers, manufacturers have to assess a multitude of complex design choices in the most e cient way possible. Even though the automotive industry is adept at dealing with the many complexities of modern vehicle development; the magnitude of design choices, the cross coupling of multiple domains, the evolving technologies and the relative lack of experience with respect to conventional vehicle development compounds the complexities within the HEV design space. In order to meet the needs of e cient and exible HEV powertrain modelling within this design space, a parallel is drawn with the development of complex software systems. This parallel is both from a programmatic viewpoint where object-oriented techniques can be used for physical model development with new equation oriented modelling environments, and from a systems methodology perspective where the development approach encourages incremental development in order to minimize risk. This Thesis proposes a modelling method that makes use of these new tools to apply OOM principles to the design and development of HEV powertrain models. Furthermore, it is argued that together with an appropriate systems engineering approach within which the model development activities will occur, the proposed method can provide a more exible and manageable manner of exploring the HEV design space.The exibility of the modelling method is shown by means of two separate case studies, where a hierarchical library of extendable and replaceable models is developed in order to model the di erent powertrains. Ultimately the proposed method leads to an intuitive manner of developing a complex system model through abstraction and incremental development of the abstracted subsystems. Having said this, the correct management of such an e ort within the automotive industry is key for ensuring the reusability of models through enforced procedures for structuring, maintaining, controlling, documenting and protecting the model development. Further, in order to integrate the new methodology into the existing systems and practices it is imperative to develop an e cient means of sharing information between all stakeholders involved. In this respect it is proposed that together with an overall systems modelling activity for tracking stakeholder involvement and providing a central point for sharing data, CAE methods can be employed in order to automate the integration of data.EThOS - Electronic Theses Online ServiceGBUnited Kingdo