Dissertations / Theses on the topic 'Chassis Control'

This thesis develops a method to integrate several automotive intelligent chassis systems, such as Anti-lock Brake System, Traction Control System, Direct Yaw Control and Active Rear Wheel Steering, using evolutionary approaches. The Integrated Vehicle Control System (IVCS) combines and supervises all controllable systems in the vehicle, optimising the over all performance and minimising the energy consumption. The IVCS is able to improve the driving safety avoiding and preventing critical or unstable situations. Furthermore, if a critical or unstable configuration is reached, the integrated system should be able to recover a stable condition. The control structure proposed in this work has as main characteristics the modularity, extensibility and flexibility, fitting the requirements of a 'plug-and-play' philosophy. The investigation is divided into four steps: Vehicle Modelling, Soft-Computing, Behaviour Based Control, and Integrated Vehicle Control System. Several mathematical vehicle models, which are applied to designing and developing the control systems, are presented. MATLAB, SIMULINK and ADAMS are used as tools to implement and simulate those models. A methodology for learning and optimisation is presented. This methodology is based on Evolutionary Algorithms, integrating the Genetic Leaming Automata, CARLA and Fuzzy Logic System. The Behaviour Based Control is introduced as the main approach to designing the controllers and coordinators. The methodology previously described is used to learn the behaviours and optimise their performance, and the same technique is applied to coordinators. Several comparisons with other controllers are also carried out. From this an Integrated Vehicle Control System is designed, developed and implemented under a virtual environment. A range of manoeuvres is carried out in order to investigate its performance under diverse conditions. The leaming and optimisation method proposed in this thesis shows effective performance being able to learn all the controller and coordinator structures. The proposed approach for IVCS also demonstrates good performance, and is well suited to a 'plug-and-play' philosophy. This research provides a foundation for the implementation of the designed controllers and coordinators in a prototype vehicle.

Le contrôle global du châssis a fait récemment l'objet d'une attention particulière. Cela serait motivé surtout par l’approche des véhicules entièrement autonomes. Ces véhicules, en particulier le niveau 5 d’automatisation SAE (J3016), devraient remplacer le conducteur humain dans presque toutes les situations. Le véhicule automatisé devrait être capable de gérer en harmonie des situations couplées où sont intégrés le contrôle longitudinal, latéral et éventuellement vertical. Pour ce faire, le véhicule dispose de plusieurs systèmes intégrés par axe de contrôle. En effet, les équipementiers automobiles et les nouveaux acteurs de l'industrie automobile proposent continuellement de nouvelles solutions pour satisfaire des performances bien spécifiques. Le constructeur automobile doit quant à lui coordonner différents sous-systèmes provenant de différentes parties prenantes afin de garantir une expérience de conduite fiable et confortable. Jusqu'à présent, les constructeurs automobiles privilégiaient des solutions simples consistant à ajouter une couche de coordination en aval des sous-systèmes concurrents afin de limiter les potentiels conflits. La plupart des stratégies adoptées consistent à prioriser un système par rapport à un autre en fonction de certains scénarios conflictuels prévisibles. Les véhicules autonomes ont besoin de sous-systèmes supplémentaires pour fonctionner en toute sécurité. Ainsi, les interactions entre les sous-systèmes s'amplifieront au point de devenir imprévisibles. Cette thèse met l'accent sur l'approche de coordination qui devrait être adoptée par les véhicules du futur. En particulier, la couche de coordination est déplacée en amont des sous-systèmes autonomes pour assurer une distribution de commande optimale. Cette couche agit comme un superviseur basé sur des algorithmes d'allocation optimale du contrôle. La synthèse des correcteurs repose sur les théories du contrôle robuste permettant de faire face aux changements environnementaux et aux incertitudes paramétriques et dynamiques du véhicule. Les résultats ont d’abord montré que même en ce qui concerne les véhicules actuels, l’approche en amont peut offrir des avantages supplémentaires pour ce qui est de la résolution de problèmes à objectifs multiples. En outre, l’approche en amont permet de coordonner les sous-systèmes des véhicules présentant une sur-actionnement plus élevé. La tolérance aux pannes peut être assurée entre des systèmes de châssis complètement différents, et des objectifs qualitatifs, s'ils sont rigoureusement formalisés, peuvent être satisfaits. Plus les sous-systèmes seront nombreux à l'avenir, plus l'approche en amont deviendrait pertinente pour le contrôle du mouvement des véhicules. Nous espérons que les avantages conséquents présentés dans cette thèse grâce à une approche de coordination en amont optimale encourageraient les constructeurs automobiles et leurs équipementiers à opter pour des solutions plus ouvertes, à proposer ensemble les normalisations nécessaires et accélérer ainsi le développement des véhicules autonomes
A large interest has been given recently to global chassis control. One of the main reasons for this would be the approach of fully autonomous vehicles. These vehicles, especially the SAE (J3016) level 5 of automation, are expected to replace the human driver in all situations. The automated vehicle should be able to manage coupled situations in harmony where longitudinal control, lateral control, and eventually vertical control are involved. To do so, the vehicle has more than one embedded system per control axis. Equipment suppliers and new entering automotive actors are continually proposing new solutions to satisfy a specific performance required from future passenger cars. Consequently, the car manufacturer has to coordinate different subsystems coming from different stakeholders to ensure a safe and comfortable driving experience. Until these days, car manufactures favoured simple solutions consisting on adding a coordination layer downstream the competing subsystems in order to mitigate eventual conflicts. Most of strategies adopted consist on prioritizing one system over another depending on predictable conflicting scenarios. Autonomous vehicles need additional subsystems to operate safely. Interactions between these subsystems will increase to the point of becoming unpredictable. This thesis focus on the coordination approach that should be adopted by future vehicles. Particularly, the coordination layer is moved upstream the standalone subsystems to ensure an optimal control distribution. This layer acts as a supervisor depending on optimization-based control allocation algorithms. The control synthesis is based on robust control theories to face environmental changes and the vehicle’s parameters and dynamics uncertainties. Results showed first that even regarding today’s vehicles, the upstream approach can offer additional advantages when it comes to multiple objectives problems solving. In addition, the upstream approach is able to coordinate subsystems of vehicles with a higher over-actuation. Fault-tolerance can be ensured between completely different chassis systems, and qualitative objectives, if rigorously formalized, can be satisfied. The more numerous subsystems will get in the future, the more relevant the upstream approach would become to vehicle motion control. We expect that the important benefits shown in this thesis thanks to an optimal upstream coordination approach would encourage car manufacturers and equipment to switch towards more open solutions, propose together the necessary standardizations, and accelerate the autonomous vehicles development

This thesis investigates the principle of co-ordination of chassis subsystems by proposing a new control structure for co-ordinating active steering technologies and a brake based directional stability controller. A non-linear vehicle handling model was developed for this study using the Mattab and Simulink tools. This consists of a 4 degree of freedom (d. o. f) lumped-parameter model that includes longitudinal, lateral, yaw and roll motions with quasi-static longitudinal load transfer effects including non-linear suspension and tyre descriptions. The non-linear vehicle dynamics are discussed for the whole operating regime and two specific driving tasks are identified, steerability and stability. In the context of the vehicle states these are yaw rate control and side slip angle bounding respectively. Linear active steering controllers for front, rear and four wheel steering are designed and evaluated in the context of the vehicle handling problem throughout the non-linear operating regime to assist the driver in the two driving tasks previously defined. It is shown through the analysis of the vehicle dynamics in the Chapter 3 that linear controllers can be used to significantly improve the handling behaviour of a non-linear vehicle when only one active input is considered, however when controlling two active inputs, non-linear multivariable approach is required to deal with the strongly coupled nature of the vehicle handling with respect to front and rear steering inputs. A brake based stability system that reflects the state of the art is implemented. The work then proposes a novel co-ordination controller structure for coordination of an active steering controllers and a brake based stability controller for improving to vehicle handling control. The controller was assessed both in steady state and transient tests selected to simulate real world driving manoeuvres over the whole non-linear vehicle handling regime. The co-ordination controller is found to lead to a trade-off between stability and limit cornering performance. The proposed structure improves vehicle stability and reduces interactions in the longitudinal vehicle motion. A detailed discussion of the implications of a coordinated control approach showing it to be a powerful tool providing, the interactions can be conveniently related vehicle handling task and that an appropriate measure of vehicle performance is available. The limitations of the approach are discussed. The most significant limitations being a) the difficulty in proving the optimalty of a heuristic control structure, b) the difficult in assessing the controller behaviour and its interaction with a real driver and c) the likely complexity of the rule base for coordinating more than 2 or 3 systems or describing more complex interactions than were observed here.

Le Contrôle Global du Châssis (CGC) est une tâche cruciale dans les véhicules intelligents. Il consiste à assister le conducteur par l'intermédiaire de plusieurs fonctionnalités automatisées, notamment à des fins de sécurité active et de confort. Etant donné que les dynamiques de ces fonctionnalités sont interconnectées, les performances attendues sont parfois contradictoires. Par conséquent, le CGC consiste à coordonner les différents systèmes ADAS « Advanced Driving Assistance Systems » afin de créer des synergies entre les dynamiques interconnectées pour améliorer les performances globales du véhicule. Plusieurs stratégies de coordination puissantes ont déjà été développées, soit dans le monde académique, soit dans le monde industriel pour gérer ces interconnexions. Du fait que les besoins en matière de sécurité active augmentent d'un côté et que la technologie pouvant être intégrée dans les véhicules évolue, une intense activité de recherche et développement est toujours en cours dans le domaine du contrôle global du châssis. Cette thèse analyse différentes interconnexions dynamiques et développe des nouvelles stratégies CGC dans lesquelles le braquage actif avant, le freinage différentiel actif et les suspensions actives sont coordonnés - tous ensemble ou partiellement afin d'améliorer les performances globales du véhicule, à savoir l'évitement du renversement, la stabilité latérale, le confort de conduite (manœuvrabilité) et confort des passagers. Plusieurs architectures multicouches formées par trois couches hiérarchiques sont proposées. La couche inférieure représente les actionneurs implémentés dans le véhicule qui génèrent leurs entrées de commande en fonction des ordres envoyés depuis la couche intermédiaire. La couche intermédiaire est la couche de contrôle qui est chargée de générer les entrées de contrôle qui minimisent les erreurs entre les variables d'état souhaitées et réelles du véhicule, à savoir les mouvements de lacet, de dérapage, de roulis, de tangage et de soulèvement, quelle que soit la situation de conduite. La couche supérieure est la couche de prise de décision. Elle surveille instantanément la dynamique du véhicule selon différents critères, puis génère des paramètres de pondération pour adapter les performances des contrôleurs en fonction des conditions de conduite, c'est-à-dire pour améliorer la manœuvrabilité, la stabilité latérale, l'évitement du renversement et le confort de conduite du véhicule. Les architectures proposées se diffèrent dans les couches de contrôle et de décision en fonction des actionneurs intégrés proposés. Par exemple, les couches de décisions se diffèrent par les critères qui surveillent la dynamique du véhicule et la manière dont la décision est prise (logique floue ou relations explicites). Les couches de contrôle se diffèrent par leurs structures, où des contrôleurs centralisés et décentralisés sont développés. Dans l'architecture centralisée, un seul contrôleur optimal MEMS Multi-Entrées-Multi-Sorties génère les entrées de commande optimales basées sur la technique de commande LPV/H∞. Dans l'architecture décentralisée, les contrôleurs sont découplés. La technique STSM (Super-Twisting Sliding Mode) est appliquée pour déduire chaque entrée de commande. Les architectures proposées sont testées et validées sur le simulateur professionnel SCANeR Studio et sur un modèle complexe non linéaire du véhicule. La simulation montre que toutes les architectures sont pertinentes pour le contrôle global du châssis. Celle centralisée est optimale, complexe et garantit la stabilité globale, tandis que celle décentralisée ne garantit pas la stabilité globale, mais elle est intuitive, simple et robuste
Global Chassis Control (GCC) is crucial task in intelligent vehicles. It consists of assisting the driver by several automated functionalities especially for active safety and comfort purposes. Due to the fact that the dynamics of these functionalities are interconnected, thus the awaited performances are sometimes contradictory. Hence, the main task in GCC field is to coordinate the different Advanced Driving Assistance Systems (ADAS) to create synergies between the interconnected dynamics in order to improve the overall vehicle performance. Several powerful coordination strategies have already been developed either in the academic world or in the industrial one to manage these interconnections. Because the active safety needs are increasing from one side, and the technology that can be embedded into vehicles is evolving, an intense research and development is still involved in the field of global chassis control. This thesis analyzes di_erent dynamics interconnections and develops new several GCC strategies where the Active Front Steering, Active Differential Braking, and the Active Suspensions are coordinated - all together or partially - to improve the vehicle overall performance i.e. the rollover avoidance, the lateral stability, the driving comfort (maneuverability), and the ride comfort. Several multilayer architectures formed by three hierarchical layers are proposed. The lower layer represents the actuators implemented into the vehicle which generate their control inputs based on the orders sent from the middle layer. The middle layer is the control layer which is responsible to generate the control inputs that minimize the errors between the desired and actual vehicle state variables i.e. the yaw, side-slip, roll, pitch, and heave motions, regardless of the driving situation. The higher layer is the decision making layer. It instantly monitors the vehicle dynamics by di_erent criteria, then, it generates weighting parameters to adapt the controllers performances according to the driving conditions i.e. to improve the vehicle's maneuverability, lateral stability, rollover avoidance, and ride comfort. The proposed architectures di_er in the control and decision layers depending on the proposed embedded actuators. For instance, the decision layers di_er in the monitored criteria and the way the decision is taken (fuzzy logic or explicit relations). The control layers di_er in structure, where centralized and decentralized controllers are developed. In the centralized architecture, one single Multi-Input-Multi-Output optimal controller generates the optimal control inputs based on the Linear Parameter Varying (LPV)/H-infinity control technique. In the decentralized architecture, the controllers are decoupled, where the Super-Twisting Sliding Mode (STSM) technique is applied to derive each control input apart. The proposed architectures are tested and validated on the professional simulator « SCANeR Studio » and on a Full vehicle nonlinear complex model. Simulation shows that all architectures are relevant to the global chassis control. The centralized one is optimal, complex and overall stability is guaranteed, while the decentralized one does not guarantee the overall stability, but it is intuitive, simple, and robust

This thesis investigates the principle of integration of vehicle dynamics control systems by proposing a novel control architecture to integrate the brake-based electronic stability control (ESC), active front steering (AFS), normal suspension force control (NFC) and variable torque distribution (VTD). A nonlinear 14 degree of freedom passive vehicle dynamics model was developed in Matlab/Simulink and validated against commercially available vehicle dynamics software CarSim. Dynamics of the four active vehicle control systems were developed. Fuzzy logic and PID control strategies were employed considering their robustness and effectiveness in controlling nonlinear systems. Effectiveness of active systems in extending the vehicle operating range against the passive ones was investigated. From the research, it was observed that AFS is effective in improving the stability at lower lateral acceleration (latac) region with less interference to the longitudinal vehicle dynamics. But its ability diminishes at higher latac regions due to tyre lateral force saturation. Both ESC and VTD are found to be effective in stabilising the vehicle over the entire operating region. But the intrusive nature of ESC promotes VTD as a preferred stability control mechanism at the medium latac range. But ESC stands out in improving stability at limits where safety is of paramount importance. NFC is observed to improve the ability to generate the tyre forces across the entire operating range. Based on this analysis, a novel rule based integrated chassis control (ICC) strategy is proposed. It uses a latac based stability criterion to assign the authority to control the stability and ensures the smooth transition of the control authority amongst the three systems, AFS, VTD and ESC respectively. The ICC also optimises the utilisation of NFC to improve the vehicle handling performance further, across the entire operating regions. The results of the simulation are found to prove that the integrated control strategy improves vehicle stability across the entire vehicle operating region.

This is the report of a master thesis in light weight design of a component in a system that harnesses wind power with a kite. The thesis is a degree project in Naval Architecture at KTH with the course code SD271X. The design work is mostly of a structural nature, but systems engineering, and conceptual design is also a major part of thestudy. The first part introduces the problem where the client, SkySails Power GmbH, is looking to design a new control pod for a system that carries 3 times the load as a previous design. The thesis is limited to the design of the load bearing chassis of the pod, but because at the time the other sub systems or components have not yetbeen designed, the study includes concept design of the entire pod system. The flight pattern and load cases of the kite are studied to get the right understanding of the forces that affect the system. The goal is to design achassis that is as affordable, light weight, and as strong as needed for the task.The requirements of the design problem are decided by the master student and the client together after a prestudy was made but they had minor changes further along the design process. It is a real life, organic iterative design process that has a goal from the start to use the opportunity of an outsider to reconsider the design of akey component of the client’s product.The result is a chassis design that is cheaper to produce and weighs less than if the old chassis would be linearly scaled up with the loads. This design has the same concept as the last but with a couple of modifications concerning some attachments to the rest of the system. The requirement of maintaining all previous functionsis achieved. A significant part of the thesis was to determine the boundaries between the areas of where FEM modelling is applicable and where hand calculations estimations are necessary. The results from this work will be used to build a prototype of the chassis, test it in a tensile testing machine, and finally integrate it into theentire system and flown.
I en värld som hotas av klimatförändringar på grund av utsläppen av fossila bränslen i atmosfären, men där människorna som befolkar den har ett stort behov av energi för sin livsstil finns det ett behov av alternativa källor och metoder till att utvinna den. Ett relativt nytt och hållbart sätt till detta är kite-baserad vindkraft. Mananvänder sig av en skärm eller drake, lite som en fallskärm fast i större storlek, som är kopplad med en vajer till en bas-station där vajern rullas upp på en trumma. Skärmen fungerar som en vinge och skapar ett lyft när den flyger i kors-vind och rullar ut vajern på trumman som fungerar samtidigt som en elektrisk generator. Alternativtlåter man skärmen ha ett konstant avstånd och har bas-stationen installerad på ett fartyg och använder lyftet från skärmen till att driva fram fartyget.Ett av företagen som arbetar med att få denna teknik lönsammare än konventionell vindkraft i vissa väder och geografiska lägen är SkySails som gav i uppdrag som examensarbete att utveckla en ny modell av chassit till styrenheten till sitt kite-system. Styrenhetens ligger mellan skärmen och vajern och har som huvudfunktion attstyra draken som görs med en mindre elektrisk motor och ett tandat bälte. Dessutom innehåller styrenheten mycket elektronik och sensorer vilket gör utvecklingen till ett komplext problem. Studentens två huvuduppgifter var göra en konceptuell utvecklingsstudie av hela styrenheten och att utveckla ett chassi, till ett stadie att dengår att tillverka från ritningar, för det mest framgångsrika konceptet. Chassit måste tåla hela skärmens laster och kosta och väga så lite som möjligt.Designprocessen var iterativ med ett systemingenjörsmässigt angreppssätt. Första delen av tiden ägnades åt att studera den befintliga styrenheten och lära sig om hela kite-teknologin. Sedan sattes tydligare och mätbara mål och specifikationer tillsammans med uppdragsgivaren. Därefter började den kreativa fasen och skissa fram bådekonventionella och okonventionella koncept för hela styrenheten. De tre mest lovande koncepten utvärderades mot de tidigare satta kriterierna så kvantifierbart som möjligt och det visade sig att det koncept som hade används var fortfarande det bästa. Sista fasen av arbetet var att sätta gränssnittet för chassit i detta koncept ochdesigna chassit så lätt som möjligt.Resultatet blev ett liknande chassi jämfört med vad det var innan men med en vikt som var lägre än om det förra chassit hade ökat sin vikt lika mycket som lastökningen. Kostnaden för chassitillverkningen gick ner i absoluta termen på grund av byte av material och tillverkningsmetod. Av detta kan man påstå att examensarbetet varframgångsrikt och nådde sina mål. Däremot måste en prototyp tillverkas testas i för att fastställa att modellerna som tog fram designen motsvarar verkligheten. Dessutom måste de andra komponenterna tillverkas i för att hela styrenheten kunna testas så som den är avsedd att användas. Chassit och styrenheten är bara ett steg på vägentill en hållbarare värld men metoderna som användes kan återanvändas.

This paper shows an electrohydraulic control system to stabilize the chassis of a mobile machine driving across an off-road ground profile. The active hydraulic suspension system is based on new electronics, SW- and control architectures and the use of state of the art industrial components. The paper shows, that the static and dynamic performance of the system is dominated by the servo valve, which represents the central component of the system.

The thesis project is performed at ÅF Industry at their chassis department in Trollhättan, where their focus lay at chassis and body functions for the automotive industry. There are many functions in a car now a day, the act and function names for those functions have a huge variety between automotive brands. ÅF want a catalogue, with a collection of functions and what they do, how they act, pros and cons, and in- & output, with focus on steering, propulsion, and suspension actuators.    Through benchmarking, all functions have been collected in a list of functions for five different automotive brands. Another student from Karlstad University, worked parallel with a similar thesis, focusing on braking actuators. Some information passed through our theses to help each other during the benchmark. From the benchmark, five datasheets were made, to add to the catalogue. Out of those five functions one had to pass the elimination matrix to be tested and evaluated.   In this thesis, the function to be tested were Drive Profile with focus on suspension. The function was tested in a Saab 9-5 Aero equipped with an VBOX 3i at NEVS test track. Test method for the test was ISO 3888-2 severe lane-change, obstacle avoidance. The result for the test was that Sport profile was stiffer than Comfort and Intelligent, and therefore recovered the roll rate much quicker in hard cornering. The profile to choose, while entry a hard cornering is the Sport profile because of the fast roll rate recovery, also the steering torque felt way better for the driver with the Sport profile activated.     It is concluded that it is a problem with all variety of function names. Especial for customer who wants to compare cars when he/she is going to buy a new car.

This thesis describes an investigation into vehicle handling control using active differentials in the rear axle of a motor vehicle. Such devices are able to transfer torque between the rear wheels and have traditionally been used to improve traction whilst minimising the impact on vehicle handling. However, the capacity to generate a lateral torque difference across an axle also gives them the potential to be used for yaw moment control. In order to generate a rigorous assessment of this potential, the investigation is carried out in three distinct phases. Firstly, an analysis of the scope for modifying vehicle handling given unrestricted control over torque transfer between the rear wheels is carded out in the simulation environment. For this purpose an idealised yaw sideslip controller is developed. This is used to show that an ideal active differential can have significant yaw moment authority in terms of generating both understeer and oversteer and that this can be used to actively modify a vehicle's handling balance and apply stability control at the limits of adhesion. In the second phase, the capabilities of two types of contemporary active differential, the torque vectoring differential (TVD) and active limited slip differential (ALSID), are then assessed against the ideal differential and against a brake based yaw moment controller. TVDs are found to be able to offer very similar performance to both their ideal counterpart and to the brake based system. They Gan also deliver this performance with a fraction of the energy loss that is observed in the brakes, thus making TVDs a viable proposition for applying continuous yaw control below the limits of adhesion. ALSDs, on the other hand do not offer equivalent functionality to an ideal active differential but are still shown to be very effective stability control devices. In the third phase, the ALSID results are validated on a prototype vehicle where it is shown that they do indeed offer substantial stability improvements both on high and low-P surfaces. However in order to deliver such benefits and be practical for implementation, it is also shown that significant redevelopment of the idealised controller is required. Finally, with the ALSID operating alongside a commercial brake based stability control system, it is proven that substantial reductions in brake intervention can be achieved without significant controller integration.

The contact between the tire and the road is the key enabler of vehicle acceleration, deceleration and steering. However, under the circumstances of sudden changes to the road conditions, the driver`s ability to maintain control of the vehicle maybe at risk. In many cases, this requires intervention from the chassis control systems onboard the vehicle. Although these systems perform well in a variety of situations, their performance can be improved if a real-time estimate of the tire-road contact parameters (ranging from kinematic conditions of the tire to its dynamic properties) are available. At the present stage of development, tire-road contact parameters are indirectly estimated using observers based on vehicle dynamics measurements (acceleration, yaw and roll rates, suspension deflections, etc). Although these methods present a relatively accurate solution, they rely heavily on tire and vehicle kinematic formulations and break down in case of abrupt changes in the measured quantities. To address this problem, researchers have been developing certain sensor based advanced tire concepts for direct measurement of the tire-road contact parameters. Thus the new terms "Intelligent Tire" and "Smart Tire", which mean online tire monitoring are thus enjoying increasing popularity among automotive manufacturers and formed the motivation for this thesis to explore the possibility of developing an intelligent tire system. The development of the so called "intelligent tire/ smart tire system" is expected to spur the development of a new generation of vehicle control system with modified control strategies, leveraging information directly coming from the interface between the tire and the road, and in turn significantly reducing the risk of accidents. The specific contributions of this thesis include the following: - Development of an intelligent tire system, with a special attention to development of measurement and sensor feature extraction methodologies of acceleration signals coming from sensors fixed to the tire innerliner - Design of an integrated vehicle state estimator for application to global chassis control - Development of a model-based tire-road friction estimation algorithm - Development of an intelligent tire based adaptive wheel slip controller for anti-lock brake system (ABS) - Development of a piezoelectric vibration energy harvesting system with an adaptive frequency tuning mechanism for intelligent tires
Master of Science

Goal of this semestral thesis is development of chassis electronic stability control ESP. Thesis analyze kinematic model of chassis, design of dynamic model, which is used for simulation of designed systems. Final system will be used in Formule Student monopost.

Active anti-roll bars have recently found greater acceptance among premium car manufacturers and optimal application of this technology has emerged as an important field of research. This thesis investigates the potential of implementing active anti-roll bars in a passenger vehicle with the purpose of increasing customer value. For active anti-roll bars, customer value is defined in terms of vehicle’s ride comfort and handling performance. The objective with this thesis is to demonstrate this value through development of a control algorithm that can reflect the potential improvement in ride comfort and handling. A vehicle with passive anti-roll bars is simulated for different manoeuvres to identify the potential and establish a reference for the development of a control algorithm and for the performance of active anti-roll bars. While ride is evaluated using single-sided cosine wave and single-sided ramps, handling is evaluated using standardized constant radius, frequency response and sine with dwell manoeuvres.The control strategy developed implements a combination of sliding mode control, feed forward and PI-controllers. Simulations with active anti-roll bars showed significant improvement in ride and handling performance in comparison to passive anti-roll bars. In ride comfort, the biggest benefit was seen in the ability to increase roll damping and isolating low frequency road excitations. For handling, most significant benefits are through the system’s ability of changing the understeer behaviour of the vehicle and improving the handling stability in transient manoeuvres. Improvement in the roll reduction capability during steady state cornering is also substantial. In conclusion, active anti-roll bars are undoubtedly capable of improving both ride comfort and handling performance of a vehicle. Although the trade-off between ride and handling performance is significantly less, balance in requirements is critical to utilise the full potential of active anti-roll bars. With a more comprehensive control strategy, they also enable the vehicle to exhibit different driving characteristics without the need for changing any additional hardware.

Le transport routier évolue considérablement vers l’électrification dans le monde entier. Un marché pour les solutions de mobilité légère électrifiée a émergé. Les dispositifs à transmission intégrale joue un rôle important dans cette nouvelle tendance. Cette technologie offre de nouvelles opportunités et pose de nouveaux défis dans le contrôle de châssis globale « Global Chassis Control (GCC) » qui a récemment atteint des niveaux remarquables. Cette étude présente une approche de supervision pour le contrôle vertical, longi-tudinal et latéral dans les véhicules électriques légers. Le système de contrôle développé repose sur la méthode CRONE qui peut assurer la robustesse du degré de stabilité contre les variations paramétriques du système. Pour la dynamique verticale, diverses solutions de contrôle sont développées pour les suspensions automobiles afin d’améliorer le confort des passagers et la tenue de route. Pour la dynamique longitudinale, une étude de la fonction ABS est réalisée pour l’amélioration du système de freinage, tenant en compte l’effet de la dynamique verticale. Ensuite, une combinaison de contrôle ABS et de contrôle de suspension est présentée dans le but de réduire l’effet de détérioration de la dynamique vertical. Enfin, les travaux portent sur le dé-veloppement du contrôle latéral de la stabilité du véhicule, où l’effet de la dynamique verticale du véhicule est analysé. Les résultats obtenus permet-tent de vérifier l’efficacité des stratégies de contrôle conçues pour améliorer le confort, la maniabilité et la sécurité du véhicule. En outre, la bonne com-préhension de l’influence de la dynamique verticale, ainsi que le rôle clé de la suspension contrôlée sur les autres dynamiques du véhicule, ouvrira de nouveaux horizons pour le développement de nouvelles stratégies pour le contrôle global du châssis des véhicules électriques légers
Road transportation is shifting significantly toward electrification around the globe. A market for light electric mobility solutions had emerged where all-in-wheel devices are expected to play an important role in this new trend. This technology offers new opportunities and raises new challenges in Global Chassis Control (GCC) that rises, recently, to remarkable levels. This study is based on a supervision control approach for vertical, longitudinal, and lateral control in light electric vehicles. The developed control system designs rely on the CRONE method which can ensure the robustness of the stability degree against the system parametric variations. For vertical dynamics, various control solu-tions are developed for automotive suspensions to improve passenger comfort and road holding. For longitudinal dynamics, a study for the ABS function is done for braking system enhancement while considering the effect of the vertical dynamics. Then, a combination of ABS control and suspension control is presented in the sense of reducing the deterioration effect of vertical dynamics. Finally, the work is concerned by the development of vehicle lateral stability control, where the effect of the vehicle vertical dynamics was analyzed. The obtained results verify the effectiveness of the designed control strategies in enhancing the vehicle comfort, handling, and safety. Moreover, the well understanding of the influence of the vertical dynamics, as well as the key role of the controlled suspension on other vehicle dynamics, will open up new prospects to the development of new strategies for global chassis control of light electric vehicle

In zunehmendem Maße werden Kraftfahrzeuge mit Sensoren zur Erfassung des Fahrzeugniveaus, also der Lage des Fahrzeugs relativ zur Straßenoberfläche in Richtung der Fahrzeughochachse, ausgestattet. Informationen zum Fahrzeugniveau werden beispielsweise für die automatische Leuchtweitenregulierung für Gasentladungsscheinwerfer und Fahrwerkregelsysteme benötigt. Mit dem Ziel der Vermeidung wesentlicher Nachteile üblicher Seriensensoren mit Kugelgelenken wurde von der ZF Lemförder Fahrwerktechnik GmbH & Co. KG in Zusammenarbeit mit der Volkswagen AG und der Technischen Universität Dresden ein Fahrzeugniveausensor prototypisch in ein Gummi-Metall-Lager eines Fahrwerklenkers integriert. In diesem mechatronischen System wird mit anisotropen magnetoresistiven (AMR) Sensoren, welche in den Lagerkern integriert sind, die Richtung des Magnetfeldes eines auf der Innenseite der äußeren Lagerhülse angeordneten Perma¬nentmagnetrings gemessen. Ein spezielles Design von Mechanik und Magnetfeld erlaubt die Messung der Lagertorsion als Maß für den vertikalen Radweg des entsprechenden Rades weitgehend unabhängig von kardanischen und translatorischen Lagerverformungen. Diese Dissertation stellt eine Zusammenfassung wesentlicher Inhalte dieses Projektes dar. Einleitend wird die Eignung von Messgröße und Sensorprinzip für die Messung des Fahrzeugniveaus anhand der Anforderungen an Fahrzeugniveausensoren diskutiert und ein optimierter mechanischer Aufbau des Sensorlagers vorgestellt. Den wissenschaftlichen Schwerpunkt dieser Dissertation bildet das Design des Magnetfeldes des erforderlichen Permanentmagneten. Auf der Basis geeigneter Ansätze erfolgt unter Anwendung der Theorie magnetischer Felder die Herleitung eines Feldverlaufs, der ein Optimum hinsichtlich der Unempfindlichkeit gegenüber der sensorischen Erfassung störender Lagerverformungen, der erreichbaren Feldstärke am Sensor, der Signallinearität und der Herstellbarkeit des Permanentmagnetrings darstellt. Zu den weiteren Themen dieser Arbeit zählen die Erörterung der verwendeten Sensorelektronik einschließlich der wesentlichen Software¬algorithmen sowie die Diskussion der experimentell ermittelten Eigenschaften eines Prototyps des Sensorlagers und dessen Komponenten
In motor vehicles, information on the position of the vehicle in direction of the vehicle height axis in relation to the road surface is increasingly provided by sensors. This positional information is required for the automatic headlight range control of gaseous discharge headlights and chassis control systems. In cooperation with Volkswagen AG and University of Technology Dresden, ZF Lemförder Fahrwerktechnik GmbH & Co. KG integrated a vehicle height sensor as a prototype in a rubber mount of an axle link with the aim of avoiding the disadvantages of standard sensors using ball joints. In this mechatronic system, the direction of the magnetic field of a permanent magnetic ring placed on the inside of the outer bearing case is measured by anisotropic magnetoresistive (AMR) sensors integrated in the centre of the bearing. The vertical movement of the relevant wheel is measured via the torsion of the rubber mount. The mechanics and the magnetic field were designed in order to get measurements that are not affected by rotational and linear rubber mount distortions. This thesis works summarizes the key points of this project. The reader will be first introduced to advantages and disadvantages of the measuring quantity and the sensor principle used for measuring the positioning of the vehicle concerning the requirements of vehicle height sensors. In addition, an optimized construction of the sensor rubber mount will be described. The main focus of this work is the design of the magnetic field of the required permanent magnet. While considering adequate approaches, the magnetic field of this magnet is formulated from the theory of magnetic fields. The presented magnetic field is an optimisation in terms of the insensitivity of sensoric measurements towards interferic rubber mount distortions, the field force that can be accomplished at the sensor, the linearity of the signal and the producibility of the permanent magnet ring. Further topics that are addressed in this thesis are the discussion of the used sensor electronic including essential software algorithms and the discussion of the experimentally derived characteristics of the prototype of the sensor rubber mount and its components

In zunehmendem Maße werden Kraftfahrzeuge mit Sensoren zur Erfassung des Fahrzeugniveaus, also der Lage des Fahrzeugs relativ zur Straßenoberfläche in Richtung der Fahrzeughochachse, ausgestattet. Informationen zum Fahrzeugniveau werden beispielsweise für die automatische Leuchtweitenregulierung für Gasentladungsscheinwerfer und Fahrwerkregelsysteme benötigt. Mit dem Ziel der Vermeidung wesentlicher Nachteile üblicher Seriensensoren mit Kugelgelenken wurde von der ZF Lemförder Fahrwerktechnik GmbH & Co. KG in Zusammenarbeit mit der Volkswagen AG und der Technischen Universität Dresden ein Fahrzeugniveausensor prototypisch in ein Gummi-Metall-Lager eines Fahrwerklenkers integriert. In diesem mechatronischen System wird mit anisotropen magnetoresistiven (AMR) Sensoren, welche in den Lagerkern integriert sind, die Richtung des Magnetfeldes eines auf der Innenseite der äußeren Lagerhülse angeordneten Perma¬nentmagnetrings gemessen. Ein spezielles Design von Mechanik und Magnetfeld erlaubt die Messung der Lagertorsion als Maß für den vertikalen Radweg des entsprechenden Rades weitgehend unabhängig von kardanischen und translatorischen Lagerverformungen. Diese Dissertation stellt eine Zusammenfassung wesentlicher Inhalte dieses Projektes dar. Einleitend wird die Eignung von Messgröße und Sensorprinzip für die Messung des Fahrzeugniveaus anhand der Anforderungen an Fahrzeugniveausensoren diskutiert und ein optimierter mechanischer Aufbau des Sensorlagers vorgestellt. Den wissenschaftlichen Schwerpunkt dieser Dissertation bildet das Design des Magnetfeldes des erforderlichen Permanentmagneten. Auf der Basis geeigneter Ansätze erfolgt unter Anwendung der Theorie magnetischer Felder die Herleitung eines Feldverlaufs, der ein Optimum hinsichtlich der Unempfindlichkeit gegenüber der sensorischen Erfassung störender Lagerverformungen, der erreichbaren Feldstärke am Sensor, der Signallinearität und der Herstellbarkeit des Permanentmagnetrings darstellt. Zu den weiteren Themen dieser Arbeit zählen die Erörterung der verwendeten Sensorelektronik einschließlich der wesentlichen Software¬algorithmen sowie die Diskussion der experimentell ermittelten Eigenschaften eines Prototyps des Sensorlagers und dessen Komponenten.
In motor vehicles, information on the position of the vehicle in direction of the vehicle height axis in relation to the road surface is increasingly provided by sensors. This positional information is required for the automatic headlight range control of gaseous discharge headlights and chassis control systems. In cooperation with Volkswagen AG and University of Technology Dresden, ZF Lemförder Fahrwerktechnik GmbH & Co. KG integrated a vehicle height sensor as a prototype in a rubber mount of an axle link with the aim of avoiding the disadvantages of standard sensors using ball joints. In this mechatronic system, the direction of the magnetic field of a permanent magnetic ring placed on the inside of the outer bearing case is measured by anisotropic magnetoresistive (AMR) sensors integrated in the centre of the bearing. The vertical movement of the relevant wheel is measured via the torsion of the rubber mount. The mechanics and the magnetic field were designed in order to get measurements that are not affected by rotational and linear rubber mount distortions. This thesis works summarizes the key points of this project. The reader will be first introduced to advantages and disadvantages of the measuring quantity and the sensor principle used for measuring the positioning of the vehicle concerning the requirements of vehicle height sensors. In addition, an optimized construction of the sensor rubber mount will be described. The main focus of this work is the design of the magnetic field of the required permanent magnet. While considering adequate approaches, the magnetic field of this magnet is formulated from the theory of magnetic fields. The presented magnetic field is an optimisation in terms of the insensitivity of sensoric measurements towards interferic rubber mount distortions, the field force that can be accomplished at the sensor, the linearity of the signal and the producibility of the permanent magnet ring. Further topics that are addressed in this thesis are the discussion of the used sensor electronic including essential software algorithms and the discussion of the experimentally derived characteristics of the prototype of the sensor rubber mount and its components.

On constate de plus en plus fréquemment la présence de systèmes électroniques dans les véhicules fabriqués aujourd’hui. Leur implantation et leur commercialisation sont dictées par la nécessité pour les constructeurs automobiles de fournir à leur clientèle un produit permettant d’avoir des performances au sommet du segment du véhicule, accompagnées par une sécurité et un confort accrus. C’est en raison de ce besoin que des systèmes pour contrôler le comportement latéral ont vu le jour. Dans cette thèse différentes stratégies de commande ont été envisagées afin de pouvoir asservir les dynamiques latérales du véhicule : des contrôleurs asservissant la dynamique de lacet et celle de roulis y sont présentés. Les actionneurs retenus sont ceux associés aux braquages des roues, au freinage ainsi qu’aux efforts des suspensions. Dans une première partie, une analyse utilisant un seul actionneur à la fois pour piloter la dynamique latérale est effectuée. Suite à ces résultats, des stratégies pilotant plusieurs actionneurs en même temps ont été développées. Vue la nécessité de garantir des performances très contraignantes tout en assurant la robustesse des contrôleurs et en prenant en compte l’évolution du comportement dynamique du véhicule, les méthodologies de commande utilisées ont été choisies parmi celles typiques de la commande robuste, à savoir l’approche H-infini/LPV, complétées par des techniques de réduction d’ordre. Les résultats obtenus nous ont permis de conclure que les méthodologies choisies sont bien adaptées à notre problématique. Nous avons aussi pu fournir des conclusions vis-à-vis des performances et des contraintes industrielles lors de l’utilisation des différentes architectures de commande pour piloter plusieurs actionneurs
Vehicles equipped with electronics systems are today commonly manufactured. The use and the commercialisation of these systems come from the necessity of the car manufacturers to give to their clients a product capable to have good driving performance together with good safety and comfort. To answer to this customer requirement, it is therefore necessary to put these systems in the new cars. In this thesis different control strategies are proposed to control the lateral dynamics of the vehicle: controllers with good performances for the yaw and roll dynamics are proposed. The proposed actuators are front steering, rear steering, brake pressure repartition and active suspensions. The thesis is divided in two parts. In the first one control laws are proposed using only one of the previous actuators to control the lateral dynamics. In the second part some strategies with two or more actuators are considered. Our control laws are obliged to guarantee good driving performances and robustness while considering the evolution of the vehicle’s dynamics. Therefore we have decided to use typical robust control methodologies like H-infinity/LPV ones completed with order reduction methods. The results obtained allow concluding that the chosen methodology is well adapted to our problem. With these results we can also give some indication about the control architecture to guarantee a good compromise between driving performances and industrialisation criteria in the case of control with two or more actuators

Les systèmes de sécurité active du véhicule de distribution sont utilisés pour réduire la survenue de situations accidentogènes ou aider le conducteur dans de telles situations pour éviter l'accident. Dans cette étude, nous nous intéressons à la prévention des accidents liés à la perte de contrôle du véhicule par le conducteur. Une partie de ces accidents peut être prévenue par l'utilisation de systèmes de sécurité active de type ESP, qui résout les problèmes d'instabilité du véhicule de type "porteur" en lacet et en roulis. Nous étudions la possibilité d'améliorer les performances de tels systèmes en combinant les actions de freins aux actions d'autres actionneurs disponibles sur le véhicule de distribution, tels que les directions actives avant et arrière. Le véhicule de distribution considéré dans notre cas est sur-actionné car le nombre d'actionneur dépasse le nombre de degrés de liberté contrôlés par ces actionneurs. Nous appliquons deux types de commande adaptés au contrôle des systèmes sur-actionnés: le premier est basé sur la structure hiérarchisée (connu sous le nom de structure avec "allocation de contrôle") et le deuxième est basé sur la structure non-hiérarchisée par "commande prédictive à base de modèle". Dans ce travail, nous adaptons ces deux approches à la problématique du contrôle du véhicule poids lourd de type "porteur". Le développement de la commande passe par la modélisation de la dynamique du véhicule, la validation des modèles et l'analyse de sa stabilité. Les résultats de simulation de prestations ISO, reproduisant des situations réelles et déstabilisantes pour le véhicule, sur le modèle représentatif du comportement réel du véhicule poids lourd démontrent l'efficacité de la commande développée et permettent d'évaluer le gain d'utilisation des actions combinées des actionneurs du véhicule par rapport au schéma classique. Ils permettent en outre de porter un jugement sur les deux types de commandes mises en œuvre.

碩士
國立臺灣科技大學
機械工程系
104
Electric Bus is usually re-assembled by conventional engine bus. In addition to environmental damage, there is not a lot of studies on four-wheel steering and drive control. This study will do the integrated chassis control of the electric bus, consider four-wheel steering ,drive control and braking system, to establish a reasonable mathematical model of the electric bus. The study include the comparison between the electric bus model and TruckSim® software model and optimal control on electric bus, in order to improve the performance , motion control and stability of electric bus.

碩士
國立雲林科技大學
電機工程系碩士班
90
The aim of this thesis is the implementation of a special-purpose service robot which has the ability to move among rough terrain. For path tracking, controllers are installed such that the robot can trace a prescribed path. Meanwhile, wireless transmission modules such as the RS-232 and the GSM are installed in order to control the mobile robot remotely. For outdoor self-localization, GPS module is also used.

Dissertação de mestrado integrado em Engenharia Eletrónica Industrial e Computadores (área de especialização em Sistemas Embebidos e Computadores)
There is an expected increase in the demand for Advanced Driver-Assistance Systems (ADAS) over the next decade, incited by regulatory and consumer interest in safety applications that protect drivers and reduce accidents [1]. Even though ADAS applications are still beginning, both the OEMs and their suppliers are realizing that they could become one of the essential characteristics differentiating the various automotive brands, consequently, one of their most important revenue sources. Furthermore, the technologies used in ADAS could be used in the future to create fully autonomous vehicles, which are now becoming a major focus of research and development. There are three main sensor solutions used in ADAS. Firstly, there are optical sensors and camera based-solutions. These are the most versatile and cost-efficient solutions. However, they are easily affected by poor weather and other environmental hazards. Furthermore, they require complex software algorithms to recognize objects [1]. The second solution incorporates short and long range Radars for determining the distance, speed, and direction of objects. These sensors work better than the others in adverse weather conditions. Nonetheless there is typically a compromise between the measurement range and angle [1]. The last type of solution involves using LiDAR systems, which use laser pulses to scan the surroundings and generate a complete and precise three-dimensional image of the environment. The LiDAR is less sensitive to light and weather conditions than optical systems and provides the location of the surrounding objects directly. Due to the ever-growing use of ADAS, there is a need to develop a more advanced LiDAR sensor. To answer that need and to overcome some of the limitations of the current LiDAR sensors, the Chassis Systems Control of the Bosch Group is developing an automotive LiDAR, and the current Master’s thesis is integrated in the project. In this Master’s thesis, an Acquisition System for Bosch’s LiDAR sensor was developed. For measuring the Time-of-Flight of the laser pulses of the LiDAR, to do so multiple TDC Peripherals were developed in an FPGA platform. The measurement precision of the developed Acquisition System varies between 232.17 ps and 188.66 ps, with an average precision of 207.47 ps.
É expectável que nas próximas décadas exista um aumento na procura das ADAS, potenciado pelos interesses dos reguladores e dos consumidores em aplicações que protejam o condutor e reduzam o número de acidentes. Tanto os OEMs, como os seus fornecedores aperceberam-se que, apesar das ADAS ainda estarem numa fase inicial, podem-se tornar uma característica diferenciadora entre as diversas marcas de automóveis, e por isso, uma das suas principais fontes de rendimento. Além disso, as tecnologias usadas nas ADAS poderão vir a ser utilizadas para criar veículos autónomos, os quais se estão a revelar como um dos principais focos da pesquisa e desenvolvimento. Existem três principais soluções de sensores usadas nas ADAS. Primeiro, existem as soluções baseadas em sensores óticos, que são as soluções mais versáteis e económicas. No entanto, este tipo de soluções é facilmente afetado pelo mau tempo e outros fatores ambientais. Para além do facto de necessitarem o uso de algoritmos complexos para reconhecerem objectos. A segunda solução incorpora o uso de RADARs de longo e curto alcance, com o objetivo de determinar a distância, velocidade e direção dos objetos. Estes sensores são pouco afetados por condições meteorológicas adversas. Porém, existe um compromisso entre o alcance e o ângulo de medição do sensor. A última solução envolve o uso de sistemas de LiDAR. Estes sistemas usam pulsos de laser para examinar meio-envolvente, de modo a gerar uma imagem tridimensional completa do mesmo. O LiDAR é menos sensível à luz e às condições meteorológicas e consegue fornecer diretamente a localização dos objetos à sua volta. Devido à crescente utilização das ADAS, existe a necessidade de desenvolver sensores LiDAR mais avançados. Para suprir essa necessidade e para ultrapassar algumas das limitações dos sensores atuais, a divisão Chassis Systems Control, do grupo Bosch, está atualmente a desenvolver uma solução de um sensor LiDAR para a indústria automóvel, projeto onde se insere esta dissertação. Nesta dissertação foi desenvolvido um Sistema de Aquisição para o sensor LiDAR. Este sistema mede o TOF dos pulsos de laser usado pelo LiDAR. Para isso, vários periféricos de TDC foram desenvolvidos numa FPGA. A precisão de medição do sistema varia entre os 232.17 ps e os 188.66 ps, com um valor médio de 207.47 ps.
This work is supported by European Structural and Investment Funds in the FEDER component, through the Operational Competitiveness and Internationalization Programme (COMPETE 2020) [Project nº 037902; Funding Reference: POCI-01-0247-FEDER-037902].

The diploma thesis, which deals with the usage of tractors with tracked chassis in the agricultural primary production, presents in a literature overview the design of the chassis of wheeled tractors, which is supplemented with front axle suspension systems. Main theoretical part of the overview describes the construction of the tracked chassis. There are mentioned and described all units of significant producers of tracked tractors. Further, the work describes the design of suspension of tracked tractors and the possibility of control of the tracked chassis. The theoretical part ends with a chapter focusing on semi-tracked tractors. Practical part shows the methodology and results of the measuring by use of the tracked tractors in the agricultural company annual production, focused on the utilization of each Tractor-set. Thesis is completed by characteristic of the general agriculture company with the analysis of the investments and costs.