A novel electromechanical brake (EMB) based on the eddy current principle is proposed for application in electrical vehicles. The proposed solution is a feasible replacement for the current conventional hydraulic brake (CHB) systems. Unlike CHBs eddy current brakes (ECBs) use eddy currents and their interaction with an externally applied magnetic field to generate braking torque. Due to their pure electrically controllable and contact free nature, ECBs have multiple advantages over the current CHB systems, such as faster response, reduced weight and number of components, ease of implementing various controllers (e.g., anti-lock braking), and reduced noise levels. However, the torque generated by a typical ECB at low speeds is insufficient to effectively and completely stop a moving vehicle. Therefore, an ECB is commonly used as an assistive brake to the CHB system in heavy vehicles, i.e. trains and trucks In order to overcome this shortcoming, the use of AC magnetic fields is proposed to realize a stand-alone ECB system in which sufficient braking torque can be generated at low speeds. To this end, eddy currents are modeled analytically using the governing Maxwell’s equations with the consideration of time varying field application. The analytical model was validated using finite element analysis. Results show that the braking torque increases with the application of a time varying field. Various forms of time varying fields have been studied. It was found that the frequency-modulated applied field in triangular waveform results in the highest braking torque. Next, the design was optimized to maximize the braking torque and an optimum configuration was obtained using multiple pole projection areas (PPAs). Optimization results show that the braking torque significantly increases with the introduction of additional PPAs to the configuration, and the braking torque generation for an optimum four-PPA ECB configuration exceeds the braking requirements for current passenger vehicles. For control purposes, a dynamic model for a novel stand-alone ECB system using AC fields for automotive applications has been successfully designed and evaluated. Also, a model-based predictive controller has been developed for the optimum ECB configuration. Finally an experimental test-bed has been designed for experimentation of both DC and AC field application on ECB. / Graduate

With the advent of autonomous driving, concepts like road trains or platoons are becoming more popular. In these arrangements, vehicles travel at separations of only 5 to 10m between them. These short inter-vehicle distances allow compacting vehicle flows resulting in increased throughput on highways. In addition, there are also fuel/energy savings as the magnitude of aerodynamic resistance acting on vehicles is reduced. These benefits increase when reducing inter-vehicle separations to below 5m. However, it becomes extremely difficult to guarantee safety, especially, when braking in an emergency. The longitudinal and lateral control systems developed so far aim to achieve string stability in the cruise scenario, i.e., to prevent that small variations at the lead magnify towards the trail. Unfortunately, this has no relevance during emergency braking, since control systems incur saturation, i.e., the condition where computed output brake forces exceed those that can be applied by actuators. This is because all vehicles have to apply their maximum brake forces in order to minimize the stopping distance of the platoon and reach a complete standstill. As a result, emergency braking requires special attention and needs to be designed and verified independent of the cruise scenario. Braking in an emergency is mainly characterized by the problem of heterogeneous deceleration capabilities of vehicles, e.g., due to their type and/or loading conditions. As a result, a deceleration rate possible by one vehicle may not be achievable by its immediately leading or following vehicles. Not addressing this heterogeneity leads to inter-vehicle collisions. Moreover, transitions in the road profile increase the complexity of such brake maneuvers. Particularly, when there is a transition from a flat road to a steep downhill, an already saturated brake controller cannot counteract the effect of the downhill slope. Hence, its deceleration magnitude will be reduced, potentially leading to intra-platoon crashes that would otherwise not occur on a flat road. In this work, we first analyze the problem of emergency braking in platoons operating at inter-vehicle separations below 5m and under idealized conditions (i.e., flat road, instantaneous deceleration, etc.). For this case, we propose a cyber-physical approach based on exploiting space buffers that are present in the separations between vehicles, and compare it with straightforward schemes (such as Least Platoon Length and Least Stopping Distance) in terms of achieved aerodynamic benefits, overall platoon length, and stopping distance. We then consider realistic conditions (in particular, changing road profiles as mentioned before) and investigate how to design a brake-by-wire controller present at each vehicle that accounts for this. We further extend our proposed cyber-physical approach by adding cooperative behavior. In particular, if an individual vehicle is unable to track its assigned deceleration, it coordinates with all others to avoid inter-vehicle collisions, for which we propose a vehicle-to-vehicle (V2V) communication strategy. Finally, we present a detailed evaluation of the proposed cyber-physical approach based on high-fidelity vehicle models in Matlab/Simulink. Even though more work is needed towards a real-life implementation, our simulation results demonstrate benefits by the proposed approach and, especially, its feasibility.

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Model-Driven Development is a development approach which is being used frequently in the automotive context in order to design models. EAST-ADL is an architectural language which models systems according to their architectural features, whereas Simulink is a tool environment which models systems according to their behavior. In this thesis work, we propose a set of transformation rules that take into consideration the EAST-ADL architectural model details and the behavioral specifications in Simulink, and generate a formal model, which can be verified UPPAAL model checker. Moreover, we implement these proposed transformation rules in a tool that automates them. The transformation rules proposed in this thesis work would be implemented for every EAST-ADL file with Simulink behavior specifications, generated by the MetaEdit+ tool. Properties like timing constraints, triggering and hierarchy in both EAST-ADL and Simulink have been considered by the transformation rules. Finally, the Brake-by-Wire case study is used to validate the tool and assess the mapping of the elements.