Abstract

In the last decades, vehicles have evolved from mechanical machines to sophisticated hardware and software (HW/SW) dominated systems. This digital paradigm shift can be explained with the rise of Advanced Driver Assistance Systems (ADAS), as well as applications of highly automated driving. However, such features require a nearly exponential amount of additional SW functionalities. To support the performance demands of such applications, powerful multi and many-processor HW platforms have been employed, exhibiting a trend toward more integrated architectures. Yet, as a consequence, the design and validation, as well as safety assessment of the digital in-vehicle infrastructure of modern cars has become immensely complex.Several techniques arose to bridge this gap, e.g., system engineering strategies, and model-based design and validation methods. In this thesis, it is proposed to augment such traditional approaches with purely simulation-driven techniques to improve and accelerate overall system design. Firstly, the utilization of driving simulators is suggested to conduct virtual road tests in an early application design stage. Furthermore, virtual prototyping is proposed to perform system exploration and extend the simulation scope of ADAS to the embedded HW/SW implementation.However, the main research contributions of the thesis are two techniques that enable efficient full-vehicle modeling. Firstly, multi-scale simulation, an approach to integrate submodels of a top-level simulation system on different design abstractions. Its main benefit is providing a tunable resolution for models, thus enabling a trade-off between the execution performance and the required simulation accuracy. Secondly, multi-domain co-simulation is proposed, a standardized method to interconnect and jointly utilize multiple vehicular simulation ecosystems. This approach addresses the multi-disciplinary nature of vehicles, requiring specialized simulators that are best suited to implement a formalism representing an individual domain.Putting all aforementioned concepts in practice, a comprehensive fully virtual ADAS prototyping ecosystem is presented in this thesis. The proposed framework assembly covers various phases of the ADAS development flow, such as model-based design, virtual system integration, virtual system testing and verification, as well as application refinement. To highlight its potentials, a multitude of ADAS applications are rapidly prototyped via the proposed system. Lastly, insights into application and system-level analyses are presented, while simulation performance evaluation is provided to highlight the acceleration potential of the virtual ecosystems.

Abstract

Formula SAE (FSAE) vehicle systems are very complex. Understanding how subsystems effect the overall vehicle is essential for making design trade-offs. FSAE is a competitive environment. Teams need to have reliable and high performing vehicles to do well in competition. The Virginia Tech (VT) FSAE team has produced a prototype electric powertrain (EPT) vehicle, VTM16e, and will take their first EPT vehicle, VTM17e, to competition in 2017. The use of model-based design (MBD) for an EPT FSAE vehicle is investigated through this thesis. The goal of the research is to build the framework of a full vehicle simulation to take knowledge gained from the VTM16e prototype vehicle, and apply it to the VTM17e competition vehicle. A top-down, bottom-up approach is taken to build a full vehicle model of an EPT FSAE vehicle. A full vehicle simulation is built with subsystems to establish an overall structure and subsystem interactions. Individual subsystems are then focused on for testing and validation. Breaking the vehicle down into subsystems allows the overall model to be incrementally improved. The battery subsystem is focused on in this thesis. Extensive testing is performed on the batteries to characterize their performance. Computer models are generated from empirical data through parameter estimation techniques. Validation of the battery models is performed and the resulting model is incorporated into the overall vehicle model. Performance limits of the vehicle are determined through model exploration, and design modifications to increase the reliability and performance for the VTM17e vehicle are proposed. Master of Science