Towards a Model-Based Multi-Layered Approach to Describe Traffic Scenarios on a Technical Level

Abstract

Highly automated vehicles are increasingly gaining the public’s attention. To achieve broad acceptance for the deployment of such vehicles, it is necessary to ensure their functionality and safety. One approach that has become popular in research is the scenario-based approach. However, manual testing of such complex systems is impractical and time-consuming. Using simulations to run and evaluate such scenarios appears to be the most viable approach. This, in turn, raises new challenges, especially in modeling the scenarios to be tested simulatively and incorporating the system under test as part of these. Since existing solutions do not solve these challenges satisfactorily—due to the strict separation of scenario and simulation model, among other reasons—this work addresses the need for a standardized, holistic, and extensible approach for modeling traffic scenarios to be executed simulatively. Requirements for such an approach are identified with focus on its application in simulation- and scenario-based verification and validation. Based on these, a model-based multi-layered approach is proposed. The foundations of this are then implemented utilizing a Meta Object Facility based heavyweight extension of the Unified Modeling Language metamodel. The resulting metamodel is used to demonstrate the applicability of the proposed approach by modeling a maritime traffic scenario.

Ad hoc HLA simulation model derived from a model-based traffic scenario

“…This is due to the fact that the simulation content and flow must be tailored to the SuT and its current development status. 17 In addition, scenario-based test runs often consider extreme and rarely occurring situations, which may require unusual and arbitrary behaviors or parameter combinations. These can also vary from scenario to scenario.…”

“…The resulting potentially problematic areas are shown in Figure 3. Since the set of possible scenario content has to represent the possible contents of a simulation run one-to-one in order to maintain compatibility and utilize the full potential of the simulation system, 17 there is a certain interdependence between the simulation and scenario models. This interdependence means that when one model is modified, the other model must also be adapted.…”

“…A possible solution to this problem was presented in a previously published work. 17 The core idea is that the simulation models are generated based on the scenario models without the need for manual adjustments. Thus, the interdependence would be resolved or, strictly speaking, obscured for the simulation developers and users.…”

“…As already touched upon in section 4, this work aims to explore how to implement the technical foundation for a realization of a previously published conceptual work. 17 The presented approach is that the simulation model are generated directly based on the scenario model. This would resolve or, strictly speaking, obscure the interdependency for the simulation system developers and users.…”

“…16 Running tests in a simulated virtual environment brings several advantages, including the ability to be able to be used during development, to be executed faster than real-time, and not to expose people and equipment to any risk. 17 Especially the use of simulation for validation of subsystems as early as during the development stages can lead to early and cost-efficient detection of errors. 17 In order to obtain meaningful results from simulative tests, an additional systematic approach is required.…”