Cette thèse étudie le problème du pilotage d'un système de direction découplé dans un véhicule. L'idée est de contrôler les deux sous-systèmes (système de restitution et système de braquage) constituant la direction de manière à : fournir au conducteur, par l'intermédiaire du volant, des sensations de conduite lui permettant d'appréhender le comportement dynamique de son véhicule ; procurer au conducteur une direction répondant à certains critères de confort ; permettre l'amélioration du comportement dynamique du véhicule en jouant sur la dynamique du système de direction. L'étude présente un modèle de référence décrivant le comportement souhaité d'un système de direction une fois implanté dans un véhicule. Ce modèle est construit de manière à prendre en compte l'influence des efforts extérieurs issus du contact pneus/sol, ceux-ci étant représentatifs du comportement dynamique du véhicule<br />Deux méthodes de commande sont proposées afin de reproduire le comportement du modèle de référence sur un système de direction découplée. Des essais sur prototype ont été réalisés et des résultats expérimentaux sont proposés.

The automotive industry is currently undergoing a paradigm shift. One such example in the next generation steering is the Steer-by-Wire (SbW) technology. SbW comes with a lot of advantages but one of the big challenges is to provide the driver with a realistic steering feel. More precisely, steering feel can be defined as the relationships between the steering wheel torque, the steering wheel angle and the dynamics of the vehicle. Accordingly, the first contribution of this work will be to present transfer functions between these quantities that resemble those observed in traditional steering systems. The steering feel/feedback is then achieved by an electric motor which can be controlled by different control strategies. In this thesis three different control strategies are investigated. The first straightforward strategy is called open loop since there is no feedback controller in the system. The second strategy is torque feedback control and the third strategy is angle feedback control. All three systems are evaluated in terms of reference tracking, stability, robustness and sensitivity. Here reference tracking is defined as tracking a desired transfer function. The desired transfer function is denoted as the reference generator. When fulfilling the requirements the analysis shows that the torque feedback system has a better reference tracking than the other evaluated systems. It is also concluded that the open loop system has a compromised reference tracking compared to the torque and angle feedback systems. Since the SbW technology is still an undergoing area of research within the automotive sector this work can be used as a basis for choice of control strategy for steering feedback systems and also as a guideline for future hardware choices.

A Controller Area Network (CAN) is a multi-master serial data communication bus designed primarily for the automotive industry. It is reliable and cost-effective and features error detection and fault confinement capabilities. CAN has been widely used in other applications, such as onboard trains, ships, construction vehicles, and aircraft. CAN has even been applied within the industrial automation segment in a range of devices such as programmable controllers, industrial robots, digital and analog I/O modules, sensors, etc. Despite its robustness and other positive features, the CAN bus has limitations in form of limited maximum data rate and maximum bus length. Also the CAN network topology is rigidly fixed which is a severe limiting factor in some of its application cases, therefore several industrial actors are evaluating alternatives to CAN. Ethernet is one of the potential candidates to replace CAN. It is a widespread and well knowntechnology, easily accessible, and many off-the-shelf solutions are available. It can support extended networks and offers wide possibilities in terms of network topology thanks to active switches. It features very high bandwidth, which has increased systematically from 10 Mbps to 100 Gbps year after year, always preserving backward compatibility to the maximum possible extent. The purpose of this thesis project is to investigate the possibility of replacing the CAN bus with Ethernet according to the following requirements: Standard off-the-shelf components and software stacks No modification of the network node application software, i.e. messages formatted accordingto CAN protocols must be transferred by means of Ethernet. A main issue is that CAN is time deterministic; it is always possible to predict the maximum latency in a message transfer. On the other hand Ethernet is still considered unreliable for time-critical applications, although the advent of Ethernet switches has minimized this non-deterministic behavior. A unique approach to this issue is offered as a result of the work done by Time Critical Networks, a newly started Swedish company. Their tool makes it possible to calculate the maximum forwarding time of a frame in an Ethernet network. This tool may make it possible to validate the use of Ethernet for time-critical applications. CPAC Systems, a company in the Volvo group which develops and manufactures steer-by-wire systems based on the CAN technology, wishes to verify whether Ethernet could now be considered as a solution to complement or replace CAN, thus overcoming CAN’s limitations. This verification is the goal of this master thesis project. The work was carried out through three different phase: First we performed a theoretical evaluation by modeling the Ethernet network using Time Critical Network’s tools. Next we verified the results by implementing the modeled CAN/Ethernet network that was previously modeled. Finally, we validated the solution by directly testing the modeled CAN/Ethernet in combination with CPAC System’s steer-by-wire technology. The results obtained show that Ethernet in combination with Time Critical Network’s modeling tool, when it comes to time-determinism, can be a complement and/or an alternative to the CAN bus. / En Controller Area Network (CAN) är en multi-master seriell datakommunikation buss utformad främst för fordonsindustrin. Den är pålitlig och kostnadseffektiv och har feldetektering och fel förmåga instängdhet. CAN har ofta används i andra tillämpningar, som ombord på tåg, fartyg, fordonkonstruktion, och flygplan. CAN har även använts inom industriautomation segmentet i en radapparater som programmerbara styrsystem, industrirobotar, digitala och analoga I/O-moduler, sensorer, etc. Trots sin robusthet och andra positiva egenskaper har CAN-bus begränsningar i form av begränsad maximal datahastighet och maximal buss längd. Även CAN nätverkstopologin är fast förankrade vilket är en svår begränsande faktor i några av dess tillämpning fall därför flera industriella aktörer utvärderar alternativ till CAN. Ethernet är en av de potentiella sökande för att ersätta CAN. Det är en utbredd och väl känd teknik, lättillgänglig, och många off-the-shelf lösningar finns tillgängliga. Det kan stödja utökade nätverk och erbjuder stora möjligheter när det gäller nätverkstopologin tack vare aktiv växlar. Den har mycket hög bandbredd, vilket har ökat systematiskt från 10 Mbps till 100 Gbps år efter år, alltid bevara bakåtkompatibilitet i största möjliga utsträckning. Syftet med detta examensarbete är att undersöka möjligheten att ersätta CAN-bussen med Ethernet i enlighet med följande krav: Standard off-the-shelf komponenter och stackar programvara Inga ändringar av nätverket nod programvara, formaterade dvs meddelanden enligt CAN protokollmåste överföras med hjälp av Ethernet. En viktig fråga är att CAN är dags deterministisk, det är alltid möjligt att förutse den maximala fördröjning i ett överfört meddelande. Å andra sidan Ethernet är fortfarande betraktas som otillförlitliga för tidskritiska applikationer, även om tillkomsten av Ethernet-switchar har minimeratdenna icke-deterministiska beteendeEn unik inställning till denna fråga är erbjuds som ett resultat av det arbete som tidskritiska Networks, ett nystartat svenskt företag. Deras verktyg gör det möjligt att beräkna den maximal avidarebefordran tid för en ram i ett Ethernet-nätverk. Detta verktyg kan göra det möjligt att valideraanvändningen av Ethernet för tidskritiska applikationer. CPAC Systems, ett bolag inom Volvokoncernen som utvecklar och tillverkar styr-by-wire-system baserade på CAN-tekniken, vill kontrollera om Ethernet nu kan betraktas som en lösning för att komplettera eller ersätta kan således övervinna CAN: s begränsningar. Denna kontroll är målet för detta examensarbete. Arbetet genomfördes genom tre olika fas: Först utförs en teoretisk utvärdering av modellering Ethernet-nätverk med hjälp av tidskritiska Networks verktyg. Nästa vi verifierat resultat genom att genomföra de modellerade CAN / Ethernet-nätverk som tidigare modellerats. Slutligen, validerade vi lösningen genom att direkt testa de modellerade CAN / Ethernet i kombination med CPAC Systems steer-by-wire-teknik. De resultat som erhållits visar att Ethernet i kombination med tidskritiska Networksmodelleringsverktyg, när det gäller tid-determinism, kan vara ett komplement och / eller ett alternativtill CAN-bussen.

The evolution of electronics in the vehicle industry has introduced the possibility for more X-by-wire systems in future vehicles. However, the use of steer-by-wire systems has not yet been widelyimplemented. This opens up an opportunity to explore strategies around the potential use of such asystem.The purpose of the project was to evaluate how to design a variable steering ratio which would give asuitable ratio in all speeds. This would, in turn, make it possible to reduce the need for large steeringwheel angles. Additionally, steering wheel designs which can be implemented with a steer-by-wiresystems are discussed and what possibilities there are to move certain interfaces to the steering wheel.The evaluation process consisted of driving a real car with a constant steering ratio in normal trafficand later modelling a variable steering ratio and testing it in a simulator. This was to get data on howlarge steering wheel angles that are needed in different driving scenarios to then be able to design asuitable variable steering ratio. The tests conducted on normal roads in a real car has shown that thedriver utilises the whole steering range (full lock-lock distance) at speeds below 30 km/h and about±10° on the steering wheel at high speeds. The tests conducted in the simulator show that the variablesteering ratio presented in this report decreases the workload on the driver most of all at speeds below30 km/h.The variable steering ratio presented has been compared with a fixed steering ratio in the simulatorand the tests show that the variable steering ratio works similar to the fixed steering ratio in the samescenarios. The variable steering ratio also decreases the need for a steering wheel angle greater than±180°.

Yes / An analysis is presented to determine the best selection criteria for the properties of a steering shaft to be used as a back-up apparatus for a steer-by-wire (SBW) system during system failure. The properties of interest are the steering-shaft stiffness and its damping coefficient. A mathematical model representing the failed state of an SBW system is derived, and a set of experiments to validate the model is presented. Once the model had been validated, further predictions of the car¿s handling behaviour for a range of steering-shaft properties and different road speeds were completed by simulations in MATLAB/Simulink. A minimum stiffness which did not cause the car to become unstable owing to overshoot was determined, and the minimum acceptable damping coefficient value was derived. It is concluded that the suggested stiffness and damping coefficient values increased the steering ratio, and the results of further investigations are presented, which confirm that the vehicle is safe to be driven in the event of SBW system failure if the recommended shaft properties are used.

Yes / The fundamentals and preliminary analyses of an innovative future technology referred to as `semi-active steering' (SAS) are presented in this article. The proposed steering system configuration is similar to a conventional electrical power-assisted steering with the replacement of the rigid steering shaft with a low stiffness resilient shaft (LSRS), the presence of which allows `active control¿ to be performed on vehicles similar to the concept of full steer-by-wire (SBW). But, unlike SBW, the LSRS is an integral part of the system characteristics. The advantages of the semi-active system in comparison with SBWand other conventional systems are demonstrated. A mathematical model to predict the mechanical properties of the LSRS has been developed, and experiments were conducted on a medium-sized car fitted with an LSRS to verify that vehicle stability and drivability can be ensured in the event of active system failure. The results have indicated that the vehicle was stable and safe to be driven at low speeds, and is predicted to be driveable and safe at higher speeds. It is concluded that an SAS system of this type has the potential to improve the safety of SBW systems.

<p>The purpose of this master thesis project has been to analyze and document the Sirius 2001 Concept Car. In addition, it has also been a goal to get the car in a usable state by implementing new software on the on board computers. </p><p>The car is a Tiger Cat E1 that is modified with four wheel steering and an advanced X-by-Wire system. The computers in the X-by-Wire system consist of six TTP PowerNodes that communicate with each other over a redundant, fault tolerant TTP/C communications bus. The computers are connected to a number of sensors and actuators to be able to control the car. </p><p>This project has contributed to the car in several ways. A complete documentation of the systems implemented in the car is one. Another is a programmers manual which significantly lowers the threshold when working with the car. Last but not least is the modifications in hardware and software, which have made the car usable and show some of the possibilities with the system. </p><p>The results show that the Sirius 2001 Concept Car is a suitable platform for research in car dynamics and fault tolerant systems. The work has also shown that the TTP/C communication model works well in an application like this.</p>

The purpose of this master thesis project has been to analyze and document the Sirius 2001 Concept Car. In addition, it has also been a goal to get the car in a usable state by implementing new software on the on board computers. The car is a Tiger Cat E1 that is modified with four wheel steering and an advanced X-by-Wire system. The computers in the X-by-Wire system consist of six TTP PowerNodes that communicate with each other over a redundant, fault tolerant TTP/C communications bus. The computers are connected to a number of sensors and actuators to be able to control the car. This project has contributed to the car in several ways. A complete documentation of the systems implemented in the car is one. Another is a programmers manual which significantly lowers the threshold when working with the car. Last but not least is the modifications in hardware and software, which have made the car usable and show some of the possibilities with the system. The results show that the Sirius 2001 Concept Car is a suitable platform for research in car dynamics and fault tolerant systems. The work has also shown that the TTP/C communication model works well in an application like this.

Simulation tools have progressed largely and in modern times they are commonly usedby engineers to design and simulate machines or part of machines before building and deploying them in the field. The field of Hardware-in-the-loop (HIL) is gaining significant interest among companies as they strive to enhance product safety and reliability simul-taneously reducing testing costs and accelerated development speed. This study presents the Real Time simulation improvements effectuated to the Steer and Brake by wire system on an underground face drill rig. These improvements in the model are validated with a comparison between simulated environment and real test data from the machine using a cosimulation between Matlab&amp;Simulink with AMESim. At the end, this improved model is prepared to be compatible with an Hardware-in-the-loop application that requires an adequate computational time.

<div>Due to recent advances in sensor technology and the exponential increase in computation power of electronic control units (ECUs) along with their increasing affordability, active safety and vehicle automation have become major trends in the commercial vehicle industry. New regulations for increased safety are also a major driver behind the industry's increased interest in that topic. As a result, being a crucial part of vehicle automation, steering systems had to be adapted to enable Active Steering. Consequently, commercial vehicle steering designers introduced the concept of torque and angle overlay using an electric motor in series with the conventional hydraulic steering system. However, despite the fact that these systems are becoming more prevalent in the market, they still suffer from inefficiencies intrinsic to the conventional hydraulic steering system still being used. These inefficiencies are a result of</div><div>flow metering losses due to the use of control valves to regulate the pump flow output, as well as inside the steering gear with the use control valves to build assistance pressure.</div><div><br></div><div><div>In this research project, we investigate the potential use of the proven pump Displacement Control (DC) technology in steering on-highway commercial vehicles. DC pumps have been shown to signicantly improve system efficiency as they allow the removal of control valves typically used to regulate </div><div>ow [1]. Instead, the displacement of the pump can be directly controlled to vary the pump's flow rate and direction,</div><div>and thus eliminating throttling losses. The DC technology has been successfully used in a steer-by-wire conguration for an articulated frame steering vehicle and has been shown to signicantly improve efficiency and productivity, as well as result in a reduction in fuel consumption [2].</div></div><div><br></div><div><div>In this work, we propose a steer-by-wire system, using DC pump technology, for on-highway commercial vehicles, and present the dierent possible congurations in which it can be implemented. Moreover, the benets and drawbacks of the steer-by-wire system are researched and identied. Subsequently, the system is designed and validated in simulation, on laboratory test setup, as well as on a test vehicle to prove its feasibility.</div></div><div><br></div><div><div>Chief among the drawbacks of the steer-by-wire system is potential failures that can lead to the complete loss of the steering function of the vehicle. As a result, different possible fail-safe mechanisms are researched from which the most suitable ones are proposed to allow the steer-by-wire system to fail safely. Moreover, two of the proposed fail-safe mechanism are implemented onto the test vehicle to prove and validate their feasibility.</div></div><div><br></div><div><div>Furthermore, an alternative way of using displacement controlled pumps for active steering is be proposed. For this concept, we investigate the possibility of actively controlling the driver's steering effort by varying the pump displacement while maintaining the mechanical link between the steering wheel and the road wheels. If successful, this method will allow for a more efficient way of providing steering assistance as it does away with the conventional control valves used to build pressure and regulate pump flow, and thus eliminating throttling losses. This method has also the advantage of having an intrinsic fail-safe mechanism with manual steering being always possible should the hydraulic or electric systems fail.</div></div>